Memory protection keys enable applications to protect its address space from inadvertent access from or corruption by itself.
These patches along with the pte-bit freeing patch series enables the protection key feature on powerpc; 4k and 64k hashpage kernels.
Will send the documentation and selftest patches separately
All patches can be found at -- https://github.com/rampai/memorykeys.git memkey.v10
The overall idea: ----------------- A process allocates a key and associates it with an address range within its address space. The process then can dynamically set read/write permissions on the key without involving the kernel. Any code that violates the permissions of the address space; as defined by its associated key, will receive a segmentation fault.
This patch series enables the feature on PPC64 HPTE platform.
ISA3.0 section 5.7.13 describes the detailed specifications.
Highlevel view of the design: --------------------------- When an application associates a key with a address address range, program the key in the Linux PTE. When the MMU detects a page fault, allocate a hash page and program the key into HPTE. And finally when the MMU detects a key violation; due to invalid application access, invoke the registered signal handler and provide the violated key number.
Testing: ------- This patch series has passed all the protection key tests available in the selftest directory.The tests are updated to work on both x86 and powerpc. The selftests have passed on x86 and powerpc hardware.
History: ------- version v10: (1) key-fault in page-fault handler is handled as normal fault and not as a bad fault. (2) changed device tree scanning to unflattened device tree. (3) fixed a bug in the logic that detected the total number of available pkeys. (4) dropped two patches. (i) sysfs interface (ii) sys_pkey_modif() syscall
version v9: (1) used jump-labels to optimize code -- Balbir (2) fixed a register initialization bug noted by Balbir (3) fixed inappropriate use of paca to pass siginfo and keys to signal handler (4) Cleanup of comment style not to be right justified -- mpe (5) restructured the patches to depend on the availability of VM_PKEY_BIT4 in include/linux/mm.h (6) Incorporated comments from Dave Hansen towards changes to selftest and got them tested on x86.
version v8: (1) Contents of the AMR register withdrawn from the siginfo structure. Applications can always read the AMR register. (2) AMR/IAMR/UAMOR are now available through ptrace system call. -- thanks to Thiago (3) code changes to handle legacy power cpus that do not support execute-disable. (4) incorporates many code improvement suggestions.
version v7: (1) refers to device tree property to enable protection keys. (2) adds 4K PTE support. (3) fixes a couple of bugs noticed by Thiago (4) decouples this patch series from arch- independent code. This patch series can now stand by itself, with one kludge patch(2). version v7: (1) refers to device tree property to enable protection keys. (2) adds 4K PTE support. (3) fixes a couple of bugs noticed by Thiago (4) decouples this patch series from arch- independent code. This patch series can now stand by itself, with one kludge patch(2).
version v6: (1) selftest changes are broken down into 20 incremental patches. (2) A separate key allocation mask that includes PKEY_DISABLE_EXECUTE is added for powerpc (3) pkey feature is enabled for 64K HPT case only. RPT and 4k HPT is disabled. (4) Documentation is updated to better capture the semantics. (5) introduced arch_pkeys_enabled() to find if an arch enables pkeys. Correspond- ing change the logic that displays key value in smaps. (6) code rearranged in many places based on comments from Dave Hansen, Balbir, Anshuman. (7) fixed one bug where a bogus key could be associated successfully in pkey_mprotect().
version v5: (1) reverted back to the old design -- store the key in the pte, instead of bypassing it. The v4 design slowed down the hash page path. (2) detects key violation when kernel is told to access user pages. (3) further refined the patches into smaller consumable units (4) page faults handlers captures the fault- ing key from the pte instead of the vma. This closes a race between where the key update in the vma and a key fault caused by the key programmed in the pte. (5) a key created with access-denied should also set it up to deny write. Fixed it. (6) protection-key number is displayed in smaps the x86 way.
version v4: (1) patches no more depend on the pte bits to program the hpte -- comment by Balbir (2) documentation updates (3) fixed a bug in the selftest. (4) unlike x86, powerpc lets signal handler change key permission bits; the change will persist across signal handler boundaries. Earlier we allowed the signal handler to modify a field in the siginfo structure which would than be used by the kernel to program the key protection register (AMR) -- resolves a issue raised by Ben. "Calls to sys_swapcontext with a made-up context will end up with a crap AMR if done by code who didn't know about that register". (5) these changes enable protection keys on 4k-page kernel aswell.
version v3: (1) split the patches into smaller consumable patches. (2) added the ability to disable execute permission on a key at creation. (3) rename calc_pte_to_hpte_pkey_bits() to pte_to_hpte_pkey_bits() -- suggested by Anshuman (4) some code optimization and clarity in do_page_fault() (5) A bug fix while invalidating a hpte slot in __hash_page_4K() -- noticed by Aneesh
version v2: (1) documentation and selftest added. (2) fixed a bug in 4k hpte backed 64k pte where page invalidation was not done correctly, and initialization of second-part-of-the-pte was not done correctly if the pte was not yet Hashed with a hpte. -- Reported by Aneesh. (3) Fixed ABI breakage caused in siginfo structure. -- Reported by Anshuman.
version v1: Initial version
Ram Pai (26): mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS is enabled mm, powerpc, x86: introduce an additional vma bit for powerpc pkey powerpc: initial pkey plumbing powerpc: track allocation status of all pkeys powerpc: helper function to read,write AMR,IAMR,UAMOR registers powerpc: helper functions to initialize AMR, IAMR and UAMOR registers powerpc: cleanup AMR, IAMR when a key is allocated or freed powerpc: implementation for arch_set_user_pkey_access() powerpc: ability to create execute-disabled pkeys powerpc: store and restore the pkey state across context switches powerpc: introduce execute-only pkey powerpc: ability to associate pkey to a vma powerpc: implementation for arch_override_mprotect_pkey() powerpc: map vma key-protection bits to pte key bits. powerpc: Program HPTE key protection bits powerpc: helper to validate key-access permissions of a pte powerpc: check key protection for user page access powerpc: implementation for arch_vma_access_permitted() powerpc: Handle exceptions caused by pkey violation powerpc: introduce get_mm_addr_key() helper powerpc: Deliver SEGV signal on pkey violation powerpc: Enable pkey subsystem powerpc: sys_pkey_alloc() and sys_pkey_free() system calls powerpc: sys_pkey_mprotect() system call mm, x86 : introduce arch_pkeys_enabled() mm: display pkey in smaps if arch_pkeys_enabled() is true
Thiago Jung Bauermann (1): powerpc/ptrace: Add memory protection key regset
arch/powerpc/Kconfig | 15 + arch/powerpc/include/asm/book3s/64/mmu-hash.h | 5 + arch/powerpc/include/asm/book3s/64/mmu.h | 10 + arch/powerpc/include/asm/book3s/64/pgtable.h | 48 +++- arch/powerpc/include/asm/bug.h | 1 + arch/powerpc/include/asm/cputable.h | 16 +- arch/powerpc/include/asm/mman.h | 13 +- arch/powerpc/include/asm/mmu.h | 9 + arch/powerpc/include/asm/mmu_context.h | 22 ++ arch/powerpc/include/asm/pkeys.h | 229 ++++++++++++ arch/powerpc/include/asm/processor.h | 5 + arch/powerpc/include/asm/reg.h | 1 - arch/powerpc/include/asm/systbl.h | 3 + arch/powerpc/include/asm/unistd.h | 6 +- arch/powerpc/include/uapi/asm/elf.h | 1 + arch/powerpc/include/uapi/asm/mman.h | 6 + arch/powerpc/include/uapi/asm/unistd.h | 3 + arch/powerpc/kernel/exceptions-64s.S | 2 +- arch/powerpc/kernel/process.c | 7 + arch/powerpc/kernel/ptrace.c | 66 ++++ arch/powerpc/kernel/traps.c | 19 +- arch/powerpc/mm/Makefile | 1 + arch/powerpc/mm/fault.c | 49 +++- arch/powerpc/mm/hash_utils_64.c | 26 ++ arch/powerpc/mm/mmu_context_book3s64.c | 2 + arch/powerpc/mm/pkeys.c | 469 +++++++++++++++++++++++++ arch/x86/include/asm/pkeys.h | 1 + arch/x86/kernel/fpu/xstate.c | 5 + arch/x86/kernel/setup.c | 8 - fs/proc/task_mmu.c | 16 +- include/linux/mm.h | 12 +- include/linux/pkeys.h | 5 + include/uapi/linux/elf.h | 1 + 33 files changed, 1040 insertions(+), 42 deletions(-) create mode 100644 arch/powerpc/include/asm/pkeys.h create mode 100644 arch/powerpc/mm/pkeys.c
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VM_PKEY_BITx are defined only if CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS is enabled. Powerpc also needs these bits. Hence lets define the VM_PKEY_BITx bits for any architecture that enables CONFIG_ARCH_HAS_PKEYS.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- fs/proc/task_mmu.c | 4 ++-- include/linux/mm.h | 9 +++++---- 2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 339e4c1..b139617 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -674,13 +674,13 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) [ilog2(VM_MERGEABLE)] = "mg", [ilog2(VM_UFFD_MISSING)]= "um", [ilog2(VM_UFFD_WP)] = "uw", -#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +#ifdef CONFIG_ARCH_HAS_PKEYS /* These come out via ProtectionKey: */ [ilog2(VM_PKEY_BIT0)] = "", [ilog2(VM_PKEY_BIT1)] = "", [ilog2(VM_PKEY_BIT2)] = "", [ilog2(VM_PKEY_BIT3)] = "", -#endif +#endif /* CONFIG_ARCH_HAS_PKEYS */ }; size_t i;
diff --git a/include/linux/mm.h b/include/linux/mm.h index ea818ff..01381d3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -228,15 +228,16 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *, #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
-#if defined(CONFIG_X86) -# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ -#if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) +#ifdef CONFIG_ARCH_HAS_PKEYS # define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0 # define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */ # define VM_PKEY_BIT1 VM_HIGH_ARCH_1 # define VM_PKEY_BIT2 VM_HIGH_ARCH_2 # define VM_PKEY_BIT3 VM_HIGH_ARCH_3 -#endif +#endif /* CONFIG_ARCH_HAS_PKEYS */ + +#if defined(CONFIG_X86) +# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ #elif defined(CONFIG_PPC) # define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */ #elif defined(CONFIG_PARISC)
Ram Pai linuxram@us.ibm.com writes:
VM_PKEY_BITx are defined only if CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS is enabled. Powerpc also needs these bits. Hence lets define the VM_PKEY_BITx bits for any architecture that enables CONFIG_ARCH_HAS_PKEYS.
Reviewed-by: Aneesh Kumar K.V aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Ram Pai linuxram@us.ibm.com
fs/proc/task_mmu.c | 4 ++-- include/linux/mm.h | 9 +++++---- 2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 339e4c1..b139617 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -674,13 +674,13 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) [ilog2(VM_MERGEABLE)] = "mg", [ilog2(VM_UFFD_MISSING)]= "um", [ilog2(VM_UFFD_WP)] = "uw", -#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +#ifdef CONFIG_ARCH_HAS_PKEYS /* These come out via ProtectionKey: */ [ilog2(VM_PKEY_BIT0)] = "", [ilog2(VM_PKEY_BIT1)] = "", [ilog2(VM_PKEY_BIT2)] = "", [ilog2(VM_PKEY_BIT3)] = "", -#endif +#endif /* CONFIG_ARCH_HAS_PKEYS */ }; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index ea818ff..01381d3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -228,15 +228,16 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *, #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ -#if defined(CONFIG_X86) -# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ -#if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) +#ifdef CONFIG_ARCH_HAS_PKEYS # define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0 # define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */ # define VM_PKEY_BIT1 VM_HIGH_ARCH_1 # define VM_PKEY_BIT2 VM_HIGH_ARCH_2 # define VM_PKEY_BIT3 VM_HIGH_ARCH_3 -#endif +#endif /* CONFIG_ARCH_HAS_PKEYS */
+#if defined(CONFIG_X86) +# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ #elif defined(CONFIG_PPC) # define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */
#elif defined(CONFIG_PARISC)
1.7.1
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Andrew,
Please apply the following two patches to your tree.
[PATCH v10 01/27] mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS is enabled [PATCH v10 02/27] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey
I have not heard any complaints on these changes. Dave Hansen had comments/suggestions in the initial revisions, which have been incorporated.
Michael Ellermen has accepted the rest of the powerpc related patches in this series.
Thanks, RP
On Thu, Jan 18, 2018 at 05:50:22PM -0800, Ram Pai wrote:
VM_PKEY_BITx are defined only if CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS is enabled. Powerpc also needs these bits. Hence lets define the VM_PKEY_BITx bits for any architecture that enables CONFIG_ARCH_HAS_PKEYS.
Signed-off-by: Ram Pai linuxram@us.ibm.com
fs/proc/task_mmu.c | 4 ++-- include/linux/mm.h | 9 +++++---- 2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 339e4c1..b139617 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -674,13 +674,13 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) [ilog2(VM_MERGEABLE)] = "mg", [ilog2(VM_UFFD_MISSING)]= "um", [ilog2(VM_UFFD_WP)] = "uw", -#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +#ifdef CONFIG_ARCH_HAS_PKEYS /* These come out via ProtectionKey: */ [ilog2(VM_PKEY_BIT0)] = "", [ilog2(VM_PKEY_BIT1)] = "", [ilog2(VM_PKEY_BIT2)] = "", [ilog2(VM_PKEY_BIT3)] = "", -#endif +#endif /* CONFIG_ARCH_HAS_PKEYS */ }; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index ea818ff..01381d3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -228,15 +228,16 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *, #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ -#if defined(CONFIG_X86) -# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ -#if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) +#ifdef CONFIG_ARCH_HAS_PKEYS # define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0 # define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */ # define VM_PKEY_BIT1 VM_HIGH_ARCH_1 # define VM_PKEY_BIT2 VM_HIGH_ARCH_2 # define VM_PKEY_BIT3 VM_HIGH_ARCH_3 -#endif +#endif /* CONFIG_ARCH_HAS_PKEYS */
+#if defined(CONFIG_X86) +# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ #elif defined(CONFIG_PPC) # define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */
#elif defined(CONFIG_PARISC)
1.7.1
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Currently only 4bits are allocated in the vma flags to hold 16 keys. This is sufficient for x86. PowerPC supports 32 keys, which needs 5bits. This patch allocates an additional bit.
Acked-by: Balbir Singh bsingharora@gmail.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- fs/proc/task_mmu.c | 1 + include/linux/mm.h | 3 ++- 2 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index b139617..0edd4da 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -680,6 +680,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) [ilog2(VM_PKEY_BIT1)] = "", [ilog2(VM_PKEY_BIT2)] = "", [ilog2(VM_PKEY_BIT3)] = "", + [ilog2(VM_PKEY_BIT4)] = "", #endif /* CONFIG_ARCH_HAS_PKEYS */ }; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index 01381d3..ebcb997 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -231,9 +231,10 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *, #ifdef CONFIG_ARCH_HAS_PKEYS # define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0 # define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */ -# define VM_PKEY_BIT1 VM_HIGH_ARCH_1 +# define VM_PKEY_BIT1 VM_HIGH_ARCH_1 /* on x86 and 5-bit value on ppc64 */ # define VM_PKEY_BIT2 VM_HIGH_ARCH_2 # define VM_PKEY_BIT3 VM_HIGH_ARCH_3 +# define VM_PKEY_BIT4 VM_HIGH_ARCH_4 #endif /* CONFIG_ARCH_HAS_PKEYS */
#if defined(CONFIG_X86)
Basic plumbing to initialize the pkey system. Nothing is enabled yet. A later patch will enable it once all the infrastructure is in place.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/Kconfig | 15 +++++++++ arch/powerpc/include/asm/mmu_context.h | 1 + arch/powerpc/include/asm/pkeys.h | 55 ++++++++++++++++++++++++++++++++ arch/powerpc/mm/Makefile | 1 + arch/powerpc/mm/hash_utils_64.c | 1 + arch/powerpc/mm/pkeys.c | 33 +++++++++++++++++++ 6 files changed, 106 insertions(+), 0 deletions(-) create mode 100644 arch/powerpc/include/asm/pkeys.h create mode 100644 arch/powerpc/mm/pkeys.c
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index c51e6ce..c9660a1 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -867,6 +867,21 @@ config SECCOMP
If unsure, say Y. Only embedded should say N here.
+config PPC_MEM_KEYS + prompt "PowerPC Memory Protection Keys" + def_bool y + depends on PPC_BOOK3S_64 + select ARCH_USES_HIGH_VMA_FLAGS + select ARCH_HAS_PKEYS + help + Memory Protection Keys provides a mechanism for enforcing + page-based protections, but without requiring modification of the + page tables when an application changes protection domains. + + For details, see Documentation/vm/protection-keys.txt + + If unsure, say y. + endmenu
config ISA_DMA_API diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 6177d43..fb5e6a3 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -192,5 +192,6 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, /* by default, allow everything */ return true; } + #endif /* __KERNEL__ */ #endif /* __ASM_POWERPC_MMU_CONTEXT_H */ diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h new file mode 100644 index 0000000..1280b35 --- /dev/null +++ b/arch/powerpc/include/asm/pkeys.h @@ -0,0 +1,55 @@ +/* + * PowerPC Memory Protection Keys management + * Copyright (c) 2017, IBM Corporation. + * Author: Ram Pai linuxram@us.ibm.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#ifndef _ASM_POWERPC_KEYS_H +#define _ASM_POWERPC_KEYS_H + +#include <linux/jump_label.h> + +DECLARE_STATIC_KEY_TRUE(pkey_disabled); +#define ARCH_VM_PKEY_FLAGS 0 + +static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) +{ + return false; +} + +static inline int mm_pkey_alloc(struct mm_struct *mm) +{ + return -1; +} + +static inline int mm_pkey_free(struct mm_struct *mm, int pkey) +{ + return -EINVAL; +} + +/* + * Try to dedicate one of the protection keys to be used as an + * execute-only protection key. + */ +static inline int execute_only_pkey(struct mm_struct *mm) +{ + return 0; +} + +static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, + int prot, int pkey) +{ + return 0; +} + +static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, + unsigned long init_val) +{ + return 0; +} +#endif /*_ASM_POWERPC_KEYS_H */ diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile index 76a6b05..181166d 100644 --- a/arch/powerpc/mm/Makefile +++ b/arch/powerpc/mm/Makefile @@ -44,3 +44,4 @@ obj-$(CONFIG_PPC_COPRO_BASE) += copro_fault.o obj-$(CONFIG_SPAPR_TCE_IOMMU) += mmu_context_iommu.o obj-$(CONFIG_PPC_PTDUMP) += dump_linuxpagetables.o obj-$(CONFIG_PPC_HTDUMP) += dump_hashpagetable.o +obj-$(CONFIG_PPC_MEM_KEYS) += pkeys.o diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 0c802de..8bd841a 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -36,6 +36,7 @@ #include <linux/memblock.h> #include <linux/context_tracking.h> #include <linux/libfdt.h> +#include <linux/pkeys.h>
#include <asm/debugfs.h> #include <asm/processor.h> diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c new file mode 100644 index 0000000..de7dc48 --- /dev/null +++ b/arch/powerpc/mm/pkeys.c @@ -0,0 +1,33 @@ +/* + * PowerPC Memory Protection Keys management + * Copyright (c) 2017, IBM Corporation. + * Author: Ram Pai linuxram@us.ibm.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/pkeys.h> + +DEFINE_STATIC_KEY_TRUE(pkey_disabled); +bool pkey_execute_disable_supported; + +int pkey_initialize(void) +{ + /* + * Disable the pkey system till everything is in place. A subsequent + * patch will enable it. + */ + static_branch_enable(&pkey_disabled); + + /* + * Disable execute_disable support for now. A subsequent patch will + * enable it. + */ + pkey_execute_disable_supported = false; + return 0; +} + +arch_initcall(pkey_initialize);
On Fri, 2018-01-19 at 01:50:24 UTC, Ram Pai wrote:
Basic plumbing to initialize the pkey system. Nothing is enabled yet. A later patch will enable it once all the infrastructure is in place.
Signed-off-by: Ram Pai linuxram@us.ibm.com
Patches 3-27 applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/92e3da3cf193fd27996909956c12a2
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Total 32 keys are available on power7 and above. However pkey 0,1 are reserved. So effectively we have 30 pkeys.
On 4K kernels, we do not have 5 bits in the PTE to represent all the keys; we only have 3bits.Two of those keys are reserved; pkey 0 and pkey 1. So effectively we have 6 pkeys.
This patch keeps track of reserved keys, allocated keys and keys that are currently free.
Also it adds skeletal functions and macros, that the architecture-independent code expects to be available.
Reviewed-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/book3s/64/mmu.h | 9 +++ arch/powerpc/include/asm/mmu_context.h | 4 + arch/powerpc/include/asm/pkeys.h | 90 ++++++++++++++++++++++++++++- arch/powerpc/mm/mmu_context_book3s64.c | 2 + arch/powerpc/mm/pkeys.c | 40 +++++++++++++ 5 files changed, 141 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h index c9448e1..37ef23c 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu.h +++ b/arch/powerpc/include/asm/book3s/64/mmu.h @@ -108,6 +108,15 @@ struct patb_entry { #ifdef CONFIG_SPAPR_TCE_IOMMU struct list_head iommu_group_mem_list; #endif + +#ifdef CONFIG_PPC_MEM_KEYS + /* + * Each bit represents one protection key. + * bit set -> key allocated + * bit unset -> key available for allocation + */ + u32 pkey_allocation_map; +#endif } mm_context_t;
/* diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index fb5e6a3..7d0f2d0 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -193,5 +193,9 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, return true; }
+#ifndef CONFIG_PPC_MEM_KEYS +#define pkey_mm_init(mm) +#endif /* CONFIG_PPC_MEM_KEYS */ + #endif /* __KERNEL__ */ #endif /* __ASM_POWERPC_MMU_CONTEXT_H */ diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 1280b35..1e8cef2 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -15,21 +15,101 @@ #include <linux/jump_label.h>
DECLARE_STATIC_KEY_TRUE(pkey_disabled); -#define ARCH_VM_PKEY_FLAGS 0 +extern int pkeys_total; /* total pkeys as per device tree */ +extern u32 initial_allocation_mask; /* bits set for reserved keys */ + +/* + * powerpc needs VM_PKEY_BIT* bit to enable pkey system. + * Without them, at least compilation needs to succeed. + */ +#ifndef VM_PKEY_BIT0 +#define VM_PKEY_SHIFT 0 +#define VM_PKEY_BIT0 0 +#define VM_PKEY_BIT1 0 +#define VM_PKEY_BIT2 0 +#define VM_PKEY_BIT3 0 +#endif + +/* + * powerpc needs an additional vma bit to support 32 keys. Till the additional + * vma bit lands in include/linux/mm.h we can only support 16 keys. + */ +#ifndef VM_PKEY_BIT4 +#define VM_PKEY_BIT4 0 +#endif + +#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \ + VM_PKEY_BIT3 | VM_PKEY_BIT4) + +#define arch_max_pkey() pkeys_total + +#define pkey_alloc_mask(pkey) (0x1 << pkey) + +#define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map) + +#define __mm_pkey_allocated(mm, pkey) { \ + mm_pkey_allocation_map(mm) |= pkey_alloc_mask(pkey); \ +} + +#define __mm_pkey_free(mm, pkey) { \ + mm_pkey_allocation_map(mm) &= ~pkey_alloc_mask(pkey); \ +} + +#define __mm_pkey_is_allocated(mm, pkey) \ + (mm_pkey_allocation_map(mm) & pkey_alloc_mask(pkey)) + +#define __mm_pkey_is_reserved(pkey) (initial_allocation_mask & \ + pkey_alloc_mask(pkey))
static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) { - return false; + /* A reserved key is never considered as 'explicitly allocated' */ + return ((pkey < arch_max_pkey()) && + !__mm_pkey_is_reserved(pkey) && + __mm_pkey_is_allocated(mm, pkey)); }
+/* + * Returns a positive, 5-bit key on success, or -1 on failure. + * Relies on the mmap_sem to protect against concurrency in mm_pkey_alloc() and + * mm_pkey_free(). + */ static inline int mm_pkey_alloc(struct mm_struct *mm) { - return -1; + /* + * Note: this is the one and only place we make sure that the pkey is + * valid as far as the hardware is concerned. The rest of the kernel + * trusts that only good, valid pkeys come out of here. + */ + u32 all_pkeys_mask = (u32)(~(0x0)); + int ret; + + if (static_branch_likely(&pkey_disabled)) + return -1; + + /* + * Are we out of pkeys? We must handle this specially because ffz() + * behavior is undefined if there are no zeros. + */ + if (mm_pkey_allocation_map(mm) == all_pkeys_mask) + return -1; + + ret = ffz((u32)mm_pkey_allocation_map(mm)); + __mm_pkey_allocated(mm, ret); + return ret; }
static inline int mm_pkey_free(struct mm_struct *mm, int pkey) { - return -EINVAL; + if (static_branch_likely(&pkey_disabled)) + return -1; + + if (!mm_pkey_is_allocated(mm, pkey)) + return -EINVAL; + + __mm_pkey_free(mm, pkey); + + return 0; }
/* @@ -52,4 +132,6 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, { return 0; } + +extern void pkey_mm_init(struct mm_struct *mm); #endif /*_ASM_POWERPC_KEYS_H */ diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c index 59c0766..929d9ef 100644 --- a/arch/powerpc/mm/mmu_context_book3s64.c +++ b/arch/powerpc/mm/mmu_context_book3s64.c @@ -16,6 +16,7 @@ #include <linux/string.h> #include <linux/types.h> #include <linux/mm.h> +#include <linux/pkeys.h> #include <linux/spinlock.h> #include <linux/idr.h> #include <linux/export.h> @@ -118,6 +119,7 @@ static int hash__init_new_context(struct mm_struct *mm)
subpage_prot_init_new_context(mm);
+ pkey_mm_init(mm); return index; }
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index de7dc48..e2f3992 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -13,21 +13,61 @@
DEFINE_STATIC_KEY_TRUE(pkey_disabled); bool pkey_execute_disable_supported; +int pkeys_total; /* Total pkeys as per device tree */ +u32 initial_allocation_mask; /* Bits set for reserved keys */
int pkey_initialize(void) { + int os_reserved, i; + /* * Disable the pkey system till everything is in place. A subsequent * patch will enable it. */ static_branch_enable(&pkey_disabled);
+ /* Lets assume 32 keys */ + pkeys_total = 32; + + /* + * Adjust the upper limit, based on the number of bits supported by + * arch-neutral code. + */ + pkeys_total = min_t(int, pkeys_total, + (ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT)); + /* * Disable execute_disable support for now. A subsequent patch will * enable it. */ pkey_execute_disable_supported = false; + +#ifdef CONFIG_PPC_4K_PAGES + /* + * The OS can manage only 8 pkeys due to its inability to represent them + * in the Linux 4K PTE. + */ + os_reserved = pkeys_total - 8; +#else + os_reserved = 0; +#endif + /* + * Bits are in LE format. NOTE: 1, 0 are reserved. + * key 0 is the default key, which allows read/write/execute. + * key 1 is recommended not to be used. PowerISA(3.0) page 1015, + * programming note. + */ + initial_allocation_mask = ~0x0; + for (i = 2; i < (pkeys_total - os_reserved); i++) + initial_allocation_mask &= ~(0x1 << i); return 0; }
arch_initcall(pkey_initialize); + +void pkey_mm_init(struct mm_struct *mm) +{ + if (static_branch_likely(&pkey_disabled)) + return; + mm_pkey_allocation_map(mm) = initial_allocation_mask; +}
Implements helper functions to read and write the key related registers; AMR, IAMR, UAMOR.
AMR register tracks the read,write permission of a key IAMR register tracks the execute permission of a key UAMOR register enables and disables a key
Acked-by: Balbir Singh bsingharora@gmail.com Reviewed-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/mm/pkeys.c | 36 ++++++++++++++++++++++++++++++++++++ 1 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index e2f3992..6e8df6e 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -71,3 +71,39 @@ void pkey_mm_init(struct mm_struct *mm) return; mm_pkey_allocation_map(mm) = initial_allocation_mask; } + +static inline u64 read_amr(void) +{ + return mfspr(SPRN_AMR); +} + +static inline void write_amr(u64 value) +{ + mtspr(SPRN_AMR, value); +} + +static inline u64 read_iamr(void) +{ + if (!likely(pkey_execute_disable_supported)) + return 0x0UL; + + return mfspr(SPRN_IAMR); +} + +static inline void write_iamr(u64 value) +{ + if (!likely(pkey_execute_disable_supported)) + return; + + mtspr(SPRN_IAMR, value); +} + +static inline u64 read_uamor(void) +{ + return mfspr(SPRN_UAMOR); +} + +static inline void write_uamor(u64 value) +{ + mtspr(SPRN_UAMOR, value); +}
Introduce helper functions that can initialize the bits in the AMR, IAMR and UAMOR register; the bits that correspond to the given pkey.
Reviewed-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/mm/pkeys.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 47 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 6e8df6e..e1dc45b 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -16,6 +16,10 @@ int pkeys_total; /* Total pkeys as per device tree */ u32 initial_allocation_mask; /* Bits set for reserved keys */
+#define AMR_BITS_PER_PKEY 2 +#define PKEY_REG_BITS (sizeof(u64)*8) +#define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey+1) * AMR_BITS_PER_PKEY)) + int pkey_initialize(void) { int os_reserved, i; @@ -107,3 +111,46 @@ static inline void write_uamor(u64 value) { mtspr(SPRN_UAMOR, value); } + +static inline void init_amr(int pkey, u8 init_bits) +{ + u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey)); + u64 old_amr = read_amr() & ~((u64)(0x3ul) << pkeyshift(pkey)); + + write_amr(old_amr | new_amr_bits); +} + +static inline void init_iamr(int pkey, u8 init_bits) +{ + u64 new_iamr_bits = (((u64)init_bits & 0x1UL) << pkeyshift(pkey)); + u64 old_iamr = read_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey)); + + write_iamr(old_iamr | new_iamr_bits); +} + +static void pkey_status_change(int pkey, bool enable) +{ + u64 old_uamor; + + /* Reset the AMR and IAMR bits for this key */ + init_amr(pkey, 0x0); + init_iamr(pkey, 0x0); + + /* Enable/disable key */ + old_uamor = read_uamor(); + if (enable) + old_uamor |= (0x3ul << pkeyshift(pkey)); + else + old_uamor &= ~(0x3ul << pkeyshift(pkey)); + write_uamor(old_uamor); +} + +void __arch_activate_pkey(int pkey) +{ + pkey_status_change(pkey, true); +} + +void __arch_deactivate_pkey(int pkey) +{ + pkey_status_change(pkey, false); +}
Cleanup the bits corresponding to a key in the AMR, and IAMR register, when the key is newly allocated/activated or is freed. We dont want some residual bits cause the hardware enforce unintended behavior when the key is activated or freed.
Reviewed-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/pkeys.h | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 1e8cef2..9964b46 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -69,6 +69,8 @@ static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) __mm_pkey_is_allocated(mm, pkey)); }
+extern void __arch_activate_pkey(int pkey); +extern void __arch_deactivate_pkey(int pkey); /* * Returns a positive, 5-bit key on success, or -1 on failure. * Relies on the mmap_sem to protect against concurrency in mm_pkey_alloc() and @@ -96,6 +98,12 @@ static inline int mm_pkey_alloc(struct mm_struct *mm)
ret = ffz((u32)mm_pkey_allocation_map(mm)); __mm_pkey_allocated(mm, ret); + + /* + * Enable the key in the hardware + */ + if (ret > 0) + __arch_activate_pkey(ret); return ret; }
@@ -107,6 +115,10 @@ static inline int mm_pkey_free(struct mm_struct *mm, int pkey) if (!mm_pkey_is_allocated(mm, pkey)) return -EINVAL;
+ /* + * Disable the key in the hardware + */ + __arch_deactivate_pkey(pkey); __mm_pkey_free(mm, pkey);
return 0;
This patch provides the detailed implementation for a user to allocate a key and enable it in the hardware.
It provides the plumbing, but it cannot be used till the system call is implemented. The next patch will do so.
Reviewed-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/pkeys.h | 6 ++++- arch/powerpc/mm/pkeys.c | 40 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 9964b46..2500a90 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -139,10 +139,14 @@ static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, return 0; }
+extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, + unsigned long init_val); static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) { - return 0; + if (static_branch_likely(&pkey_disabled)) + return -EINVAL; + return __arch_set_user_pkey_access(tsk, pkey, init_val); }
extern void pkey_mm_init(struct mm_struct *mm); diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index e1dc45b..eca04cd 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -9,6 +9,7 @@ * (at your option) any later version. */
+#include <asm/mman.h> #include <linux/pkeys.h>
DEFINE_STATIC_KEY_TRUE(pkey_disabled); @@ -17,6 +18,9 @@ u32 initial_allocation_mask; /* Bits set for reserved keys */
#define AMR_BITS_PER_PKEY 2 +#define AMR_RD_BIT 0x1UL +#define AMR_WR_BIT 0x2UL +#define IAMR_EX_BIT 0x1UL #define PKEY_REG_BITS (sizeof(u64)*8) #define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey+1) * AMR_BITS_PER_PKEY))
@@ -112,6 +116,20 @@ static inline void write_uamor(u64 value) mtspr(SPRN_UAMOR, value); }
+static bool is_pkey_enabled(int pkey) +{ + u64 uamor = read_uamor(); + u64 pkey_bits = 0x3ul << pkeyshift(pkey); + u64 uamor_pkey_bits = (uamor & pkey_bits); + + /* + * Both the bits in UAMOR corresponding to the key should be set or + * reset. + */ + WARN_ON(uamor_pkey_bits && (uamor_pkey_bits != pkey_bits)); + return !!(uamor_pkey_bits); +} + static inline void init_amr(int pkey, u8 init_bits) { u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey)); @@ -154,3 +172,25 @@ void __arch_deactivate_pkey(int pkey) { pkey_status_change(pkey, false); } + +/* + * Set the access rights in AMR IAMR and UAMOR registers for @pkey to that + * specified in @init_val. + */ +int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, + unsigned long init_val) +{ + u64 new_amr_bits = 0x0ul; + + if (!is_pkey_enabled(pkey)) + return -EINVAL; + + /* Set the bits we need in AMR: */ + if (init_val & PKEY_DISABLE_ACCESS) + new_amr_bits |= AMR_RD_BIT | AMR_WR_BIT; + else if (init_val & PKEY_DISABLE_WRITE) + new_amr_bits |= AMR_WR_BIT; + + init_amr(pkey, new_amr_bits); + return 0; +}
powerpc has hardware support to disable execute on a pkey. This patch enables the ability to create execute-disabled keys.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/uapi/asm/mman.h | 6 ++++++ arch/powerpc/mm/pkeys.c | 16 ++++++++++++++++ 2 files changed, 22 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/uapi/asm/mman.h b/arch/powerpc/include/uapi/asm/mman.h index e63bc37..65065ce 100644 --- a/arch/powerpc/include/uapi/asm/mman.h +++ b/arch/powerpc/include/uapi/asm/mman.h @@ -30,4 +30,10 @@ #define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */ #define MAP_HUGETLB 0x40000 /* create a huge page mapping */
+/* Override any generic PKEY permission defines */ +#define PKEY_DISABLE_EXECUTE 0x4 +#undef PKEY_ACCESS_MASK +#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\ + PKEY_DISABLE_WRITE |\ + PKEY_DISABLE_EXECUTE) #endif /* _UAPI_ASM_POWERPC_MMAN_H */ diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index eca04cd..39e9814 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -29,6 +29,14 @@ int pkey_initialize(void) int os_reserved, i;
/* + * We define PKEY_DISABLE_EXECUTE in addition to the arch-neutral + * generic defines for PKEY_DISABLE_ACCESS and PKEY_DISABLE_WRITE. + * Ensure that the bits a distinct. + */ + BUILD_BUG_ON(PKEY_DISABLE_EXECUTE & + (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)); + + /* * Disable the pkey system till everything is in place. A subsequent * patch will enable it. */ @@ -181,10 +189,18 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) { u64 new_amr_bits = 0x0ul; + u64 new_iamr_bits = 0x0ul;
if (!is_pkey_enabled(pkey)) return -EINVAL;
+ if (init_val & PKEY_DISABLE_EXECUTE) { + if (!pkey_execute_disable_supported) + return -EINVAL; + new_iamr_bits |= IAMR_EX_BIT; + } + init_iamr(pkey, new_iamr_bits); + /* Set the bits we need in AMR: */ if (init_val & PKEY_DISABLE_ACCESS) new_amr_bits |= AMR_RD_BIT | AMR_WR_BIT;
Store and restore the AMR, IAMR and UAMOR register state of the task before scheduling out and after scheduling in, respectively.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/mmu_context.h | 3 ++ arch/powerpc/include/asm/pkeys.h | 4 ++ arch/powerpc/include/asm/processor.h | 5 +++ arch/powerpc/kernel/process.c | 7 ++++ arch/powerpc/mm/pkeys.c | 52 +++++++++++++++++++++++++++++++- 5 files changed, 70 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 7d0f2d0..4d69223 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -195,6 +195,9 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
#ifndef CONFIG_PPC_MEM_KEYS #define pkey_mm_init(mm) +#define thread_pkey_regs_save(thread) +#define thread_pkey_regs_restore(new_thread, old_thread) +#define thread_pkey_regs_init(thread) #endif /* CONFIG_PPC_MEM_KEYS */
#endif /* __KERNEL__ */ diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 2500a90..3def5af 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -150,4 +150,8 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, }
extern void pkey_mm_init(struct mm_struct *mm); +extern void thread_pkey_regs_save(struct thread_struct *thread); +extern void thread_pkey_regs_restore(struct thread_struct *new_thread, + struct thread_struct *old_thread); +extern void thread_pkey_regs_init(struct thread_struct *thread); #endif /*_ASM_POWERPC_KEYS_H */ diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index bdab3b7..01299cd 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -309,6 +309,11 @@ struct thread_struct { struct thread_vr_state ckvr_state; /* Checkpointed VR state */ unsigned long ckvrsave; /* Checkpointed VRSAVE */ #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ +#ifdef CONFIG_PPC_MEM_KEYS + unsigned long amr; + unsigned long iamr; + unsigned long uamor; +#endif #ifdef CONFIG_KVM_BOOK3S_32_HANDLER void* kvm_shadow_vcpu; /* KVM internal data */ #endif /* CONFIG_KVM_BOOK3S_32_HANDLER */ diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 5acb5a1..6447f80 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -42,6 +42,7 @@ #include <linux/hw_breakpoint.h> #include <linux/uaccess.h> #include <linux/elf-randomize.h> +#include <linux/pkeys.h>
#include <asm/pgtable.h> #include <asm/io.h> @@ -1102,6 +1103,8 @@ static inline void save_sprs(struct thread_struct *t) t->tar = mfspr(SPRN_TAR); } #endif + + thread_pkey_regs_save(t); }
static inline void restore_sprs(struct thread_struct *old_thread, @@ -1141,6 +1144,8 @@ static inline void restore_sprs(struct thread_struct *old_thread, old_thread->tidr != new_thread->tidr) mtspr(SPRN_TIDR, new_thread->tidr); #endif + + thread_pkey_regs_restore(new_thread, old_thread); }
#ifdef CONFIG_PPC_BOOK3S_64 @@ -1865,6 +1870,8 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp) current->thread.tm_tfiar = 0; current->thread.load_tm = 0; #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ + + thread_pkey_regs_init(¤t->thread); } EXPORT_SYMBOL(start_thread);
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 39e9814..7dfcf2d 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -16,6 +16,8 @@ bool pkey_execute_disable_supported; int pkeys_total; /* Total pkeys as per device tree */ u32 initial_allocation_mask; /* Bits set for reserved keys */ +u64 pkey_amr_uamor_mask; /* Bits in AMR/UMOR not to be touched */ +u64 pkey_iamr_mask; /* Bits in AMR not to be touched */
#define AMR_BITS_PER_PKEY 2 #define AMR_RD_BIT 0x1UL @@ -74,8 +76,16 @@ int pkey_initialize(void) * programming note. */ initial_allocation_mask = ~0x0; - for (i = 2; i < (pkeys_total - os_reserved); i++) + + /* register mask is in BE format */ + pkey_amr_uamor_mask = ~0x0ul; + pkey_iamr_mask = ~0x0ul; + + for (i = 2; i < (pkeys_total - os_reserved); i++) { initial_allocation_mask &= ~(0x1 << i); + pkey_amr_uamor_mask &= ~(0x3ul << pkeyshift(i)); + pkey_iamr_mask &= ~(0x1ul << pkeyshift(i)); + } return 0; }
@@ -210,3 +220,43 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, init_amr(pkey, new_amr_bits); return 0; } + +void thread_pkey_regs_save(struct thread_struct *thread) +{ + if (static_branch_likely(&pkey_disabled)) + return; + + /* + * TODO: Skip saving registers if @thread hasn't used any keys yet. + */ + thread->amr = read_amr(); + thread->iamr = read_iamr(); + thread->uamor = read_uamor(); +} + +void thread_pkey_regs_restore(struct thread_struct *new_thread, + struct thread_struct *old_thread) +{ + if (static_branch_likely(&pkey_disabled)) + return; + + /* + * TODO: Just set UAMOR to zero if @new_thread hasn't used any keys yet. + */ + if (old_thread->amr != new_thread->amr) + write_amr(new_thread->amr); + if (old_thread->iamr != new_thread->iamr) + write_iamr(new_thread->iamr); + if (old_thread->uamor != new_thread->uamor) + write_uamor(new_thread->uamor); +} + +void thread_pkey_regs_init(struct thread_struct *thread) +{ + if (static_branch_likely(&pkey_disabled)) + return; + + write_amr(read_amr() & pkey_amr_uamor_mask); + write_iamr(read_iamr() & pkey_iamr_mask); + write_uamor(read_uamor() & pkey_amr_uamor_mask); +}
This patch provides the implementation of execute-only pkey. The architecture-independent layer expects the arch-dependent layer, to support the ability to create and enable a special key which has execute-only permission.
Acked-by: Balbir Singh bsingharora@gmail.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/book3s/64/mmu.h | 1 + arch/powerpc/include/asm/pkeys.h | 6 +++- arch/powerpc/mm/pkeys.c | 58 ++++++++++++++++++++++++++++++ 3 files changed, 64 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h index 37ef23c..0abeb0e 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu.h +++ b/arch/powerpc/include/asm/book3s/64/mmu.h @@ -116,6 +116,7 @@ struct patb_entry { * bit unset -> key available for allocation */ u32 pkey_allocation_map; + s16 execute_only_pkey; /* key holding execute-only protection */ #endif } mm_context_t;
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 3def5af..2b5bb35 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -128,9 +128,13 @@ static inline int mm_pkey_free(struct mm_struct *mm, int pkey) * Try to dedicate one of the protection keys to be used as an * execute-only protection key. */ +extern int __execute_only_pkey(struct mm_struct *mm); static inline int execute_only_pkey(struct mm_struct *mm) { - return 0; + if (static_branch_likely(&pkey_disabled)) + return -1; + + return __execute_only_pkey(mm); }
static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 7dfcf2d..b466a2c 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -96,6 +96,8 @@ void pkey_mm_init(struct mm_struct *mm) if (static_branch_likely(&pkey_disabled)) return; mm_pkey_allocation_map(mm) = initial_allocation_mask; + /* -1 means unallocated or invalid */ + mm->context.execute_only_pkey = -1; }
static inline u64 read_amr(void) @@ -260,3 +262,59 @@ void thread_pkey_regs_init(struct thread_struct *thread) write_iamr(read_iamr() & pkey_iamr_mask); write_uamor(read_uamor() & pkey_amr_uamor_mask); } + +static inline bool pkey_allows_readwrite(int pkey) +{ + int pkey_shift = pkeyshift(pkey); + + if (!is_pkey_enabled(pkey)) + return true; + + return !(read_amr() & ((AMR_RD_BIT|AMR_WR_BIT) << pkey_shift)); +} + +int __execute_only_pkey(struct mm_struct *mm) +{ + bool need_to_set_mm_pkey = false; + int execute_only_pkey = mm->context.execute_only_pkey; + int ret; + + /* Do we need to assign a pkey for mm's execute-only maps? */ + if (execute_only_pkey == -1) { + /* Go allocate one to use, which might fail */ + execute_only_pkey = mm_pkey_alloc(mm); + if (execute_only_pkey < 0) + return -1; + need_to_set_mm_pkey = true; + } + + /* + * We do not want to go through the relatively costly dance to set AMR + * if we do not need to. Check it first and assume that if the + * execute-only pkey is readwrite-disabled than we do not have to set it + * ourselves. + */ + if (!need_to_set_mm_pkey && !pkey_allows_readwrite(execute_only_pkey)) + return execute_only_pkey; + + /* + * Set up AMR so that it denies access for everything other than + * execution. + */ + ret = __arch_set_user_pkey_access(current, execute_only_pkey, + PKEY_DISABLE_ACCESS | + PKEY_DISABLE_WRITE); + /* + * If the AMR-set operation failed somehow, just return 0 and + * effectively disable execute-only support. + */ + if (ret) { + mm_pkey_free(mm, execute_only_pkey); + return -1; + } + + /* We got one, store it and use it from here on out */ + if (need_to_set_mm_pkey) + mm->context.execute_only_pkey = execute_only_pkey; + return execute_only_pkey; +}
arch-independent code expects the arch to map a pkey into the vma's protection bit setting. The patch provides that ability.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/mman.h | 7 ++++++- arch/powerpc/include/asm/pkeys.h | 11 +++++++++++ arch/powerpc/mm/pkeys.c | 8 ++++++++ 3 files changed, 25 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h index 30922f6..2999478 100644 --- a/arch/powerpc/include/asm/mman.h +++ b/arch/powerpc/include/asm/mman.h @@ -13,6 +13,7 @@
#include <asm/cputable.h> #include <linux/mm.h> +#include <linux/pkeys.h> #include <asm/cpu_has_feature.h>
/* @@ -22,7 +23,11 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, unsigned long pkey) { - return (prot & PROT_SAO) ? VM_SAO : 0; +#ifdef CONFIG_PPC_MEM_KEYS + return (((prot & PROT_SAO) ? VM_SAO : 0) | pkey_to_vmflag_bits(pkey)); +#else + return ((prot & PROT_SAO) ? VM_SAO : 0); +#endif } #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 2b5bb35..c7cc433 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -41,6 +41,17 @@ #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \ VM_PKEY_BIT3 | VM_PKEY_BIT4)
+/* Override any generic PKEY permission defines */ +#define PKEY_DISABLE_EXECUTE 0x4 +#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS | \ + PKEY_DISABLE_WRITE | \ + PKEY_DISABLE_EXECUTE) + +static inline u64 pkey_to_vmflag_bits(u16 pkey) +{ + return (((u64)pkey << VM_PKEY_SHIFT) & ARCH_VM_PKEY_FLAGS); +} + #define arch_max_pkey() pkeys_total
#define pkey_alloc_mask(pkey) (0x1 << pkey) diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index b466a2c..ee31ab5 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -39,6 +39,14 @@ int pkey_initialize(void) (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
/* + * pkey_to_vmflag_bits() assumes that the pkey bits are contiguous + * in the vmaflag. Make sure that is really the case. + */ + BUILD_BUG_ON(__builtin_clzl(ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT) + + __builtin_popcountl(ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT) + != (sizeof(u64) * BITS_PER_BYTE)); + + /* * Disable the pkey system till everything is in place. A subsequent * patch will enable it. */
arch independent code calls arch_override_mprotect_pkey() to return a pkey that best matches the requested protection.
This patch provides the implementation.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/mmu_context.h | 5 ++++ arch/powerpc/include/asm/pkeys.h | 21 +++++++++++++++++- arch/powerpc/mm/pkeys.c | 36 ++++++++++++++++++++++++++++++++ 3 files changed, 61 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 4d69223..3ba571d 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -198,6 +198,11 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, #define thread_pkey_regs_save(thread) #define thread_pkey_regs_restore(new_thread, old_thread) #define thread_pkey_regs_init(thread) + +static inline int vma_pkey(struct vm_area_struct *vma) +{ + return 0; +} #endif /* CONFIG_PPC_MEM_KEYS */
#endif /* __KERNEL__ */ diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index c7cc433..0a643b8 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -52,6 +52,13 @@ static inline u64 pkey_to_vmflag_bits(u16 pkey) return (((u64)pkey << VM_PKEY_SHIFT) & ARCH_VM_PKEY_FLAGS); }
+static inline int vma_pkey(struct vm_area_struct *vma) +{ + if (static_branch_likely(&pkey_disabled)) + return 0; + return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT; +} + #define arch_max_pkey() pkeys_total
#define pkey_alloc_mask(pkey) (0x1 << pkey) @@ -148,10 +155,22 @@ static inline int execute_only_pkey(struct mm_struct *mm) return __execute_only_pkey(mm); }
+extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma, + int prot, int pkey); static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey) { - return 0; + if (static_branch_likely(&pkey_disabled)) + return 0; + + /* + * Is this an mprotect_pkey() call? If so, never override the value that + * came from the user. + */ + if (pkey != -1) + return pkey; + + return __arch_override_mprotect_pkey(vma, prot, pkey); }
extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index ee31ab5..7630c2f 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -326,3 +326,39 @@ int __execute_only_pkey(struct mm_struct *mm) mm->context.execute_only_pkey = execute_only_pkey; return execute_only_pkey; } + +static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma) +{ + /* Do this check first since the vm_flags should be hot */ + if ((vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) != VM_EXEC) + return false; + + return (vma_pkey(vma) == vma->vm_mm->context.execute_only_pkey); +} + +/* + * This should only be called for *plain* mprotect calls. + */ +int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, + int pkey) +{ + /* + * If the currently associated pkey is execute-only, but the requested + * protection requires read or write, move it back to the default pkey. + */ + if (vma_is_pkey_exec_only(vma) && (prot & (PROT_READ | PROT_WRITE))) + return 0; + + /* + * The requested protection is execute-only. Hence let's use an + * execute-only pkey. + */ + if (prot == PROT_EXEC) { + pkey = execute_only_pkey(vma->vm_mm); + if (pkey > 0) + return pkey; + } + + /* Nothing to override. */ + return vma_pkey(vma); +}
Map the key protection bits of the vma to the pkey bits in the PTE.
The PTE bits used for pkey are 3,4,5,6 and 57. The first four bits are the same four bits that were freed up initially in this patch series. remember? :-) Without those four bits this patch wouldn't be possible.
BUT, on 4k kernel, bit 3, and 4 could not be freed up. remember? Hence we have to be satisfied with 5, 6 and 7.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/book3s/64/pgtable.h | 25 ++++++++++++++++++++++++- arch/powerpc/include/asm/mman.h | 6 ++++++ arch/powerpc/include/asm/pkeys.h | 12 ++++++++++++ 3 files changed, 42 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 4469781..e1a8bb6 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -39,6 +39,7 @@ #define _RPAGE_RSV2 0x0800000000000000UL #define _RPAGE_RSV3 0x0400000000000000UL #define _RPAGE_RSV4 0x0200000000000000UL +#define _RPAGE_RSV5 0x00040UL
#define _PAGE_PTE 0x4000000000000000UL /* distinguishes PTEs from pointers */ #define _PAGE_PRESENT 0x8000000000000000UL /* pte contains a translation */ @@ -58,6 +59,25 @@ /* Max physical address bit as per radix table */ #define _RPAGE_PA_MAX 57
+#ifdef CONFIG_PPC_MEM_KEYS +#ifdef CONFIG_PPC_64K_PAGES +#define H_PTE_PKEY_BIT0 _RPAGE_RSV1 +#define H_PTE_PKEY_BIT1 _RPAGE_RSV2 +#else /* CONFIG_PPC_64K_PAGES */ +#define H_PTE_PKEY_BIT0 0 /* _RPAGE_RSV1 is not available */ +#define H_PTE_PKEY_BIT1 0 /* _RPAGE_RSV2 is not available */ +#endif /* CONFIG_PPC_64K_PAGES */ +#define H_PTE_PKEY_BIT2 _RPAGE_RSV3 +#define H_PTE_PKEY_BIT3 _RPAGE_RSV4 +#define H_PTE_PKEY_BIT4 _RPAGE_RSV5 +#else /* CONFIG_PPC_MEM_KEYS */ +#define H_PTE_PKEY_BIT0 0 +#define H_PTE_PKEY_BIT1 0 +#define H_PTE_PKEY_BIT2 0 +#define H_PTE_PKEY_BIT3 0 +#define H_PTE_PKEY_BIT4 0 +#endif /* CONFIG_PPC_MEM_KEYS */ + /* * Max physical address bit we will use for now. * @@ -121,13 +141,16 @@ #define _PAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \ _PAGE_ACCESSED | _PAGE_SPECIAL | _PAGE_PTE | \ _PAGE_SOFT_DIRTY) + +#define H_PTE_PKEY (H_PTE_PKEY_BIT0 | H_PTE_PKEY_BIT1 | H_PTE_PKEY_BIT2 | \ + H_PTE_PKEY_BIT3 | H_PTE_PKEY_BIT4) /* * Mask of bits returned by pte_pgprot() */ #define PAGE_PROT_BITS (_PAGE_SAO | _PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT | \ H_PAGE_4K_PFN | _PAGE_PRIVILEGED | _PAGE_ACCESSED | \ _PAGE_READ | _PAGE_WRITE | _PAGE_DIRTY | _PAGE_EXEC | \ - _PAGE_SOFT_DIRTY) + _PAGE_SOFT_DIRTY | H_PTE_PKEY) /* * We define 2 sets of base prot bits, one for basic pages (ie, * cacheable kernel and user pages) and one for non cacheable diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h index 2999478..07e3f54 100644 --- a/arch/powerpc/include/asm/mman.h +++ b/arch/powerpc/include/asm/mman.h @@ -33,7 +33,13 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags) { +#ifdef CONFIG_PPC_MEM_KEYS + return (vm_flags & VM_SAO) ? + __pgprot(_PAGE_SAO | vmflag_to_pte_pkey_bits(vm_flags)) : + __pgprot(0 | vmflag_to_pte_pkey_bits(vm_flags)); +#else return (vm_flags & VM_SAO) ? __pgprot(_PAGE_SAO) : __pgprot(0); +#endif } #define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 0a643b8..f65dedd 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -52,6 +52,18 @@ static inline u64 pkey_to_vmflag_bits(u16 pkey) return (((u64)pkey << VM_PKEY_SHIFT) & ARCH_VM_PKEY_FLAGS); }
+static inline u64 vmflag_to_pte_pkey_bits(u64 vm_flags) +{ + if (static_branch_likely(&pkey_disabled)) + return 0x0UL; + + return (((vm_flags & VM_PKEY_BIT0) ? H_PTE_PKEY_BIT4 : 0x0UL) | + ((vm_flags & VM_PKEY_BIT1) ? H_PTE_PKEY_BIT3 : 0x0UL) | + ((vm_flags & VM_PKEY_BIT2) ? H_PTE_PKEY_BIT2 : 0x0UL) | + ((vm_flags & VM_PKEY_BIT3) ? H_PTE_PKEY_BIT1 : 0x0UL) | + ((vm_flags & VM_PKEY_BIT4) ? H_PTE_PKEY_BIT0 : 0x0UL)); +} + static inline int vma_pkey(struct vm_area_struct *vma) { if (static_branch_likely(&pkey_disabled))
Map the PTE protection key bits to the HPTE key protection bits, while creating HPTE entries.
Acked-by: Balbir Singh bsingharora@gmail.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/book3s/64/mmu-hash.h | 5 +++++ arch/powerpc/include/asm/mmu_context.h | 6 ++++++ arch/powerpc/include/asm/pkeys.h | 9 +++++++++ arch/powerpc/mm/hash_utils_64.c | 1 + 4 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h index e91e115..50ed64f 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h @@ -90,6 +90,8 @@ #define HPTE_R_PP0 ASM_CONST(0x8000000000000000) #define HPTE_R_TS ASM_CONST(0x4000000000000000) #define HPTE_R_KEY_HI ASM_CONST(0x3000000000000000) +#define HPTE_R_KEY_BIT0 ASM_CONST(0x2000000000000000) +#define HPTE_R_KEY_BIT1 ASM_CONST(0x1000000000000000) #define HPTE_R_RPN_SHIFT 12 #define HPTE_R_RPN ASM_CONST(0x0ffffffffffff000) #define HPTE_R_RPN_3_0 ASM_CONST(0x01fffffffffff000) @@ -104,6 +106,9 @@ #define HPTE_R_C ASM_CONST(0x0000000000000080) #define HPTE_R_R ASM_CONST(0x0000000000000100) #define HPTE_R_KEY_LO ASM_CONST(0x0000000000000e00) +#define HPTE_R_KEY_BIT2 ASM_CONST(0x0000000000000800) +#define HPTE_R_KEY_BIT3 ASM_CONST(0x0000000000000400) +#define HPTE_R_KEY_BIT4 ASM_CONST(0x0000000000000200) #define HPTE_R_KEY (HPTE_R_KEY_LO | HPTE_R_KEY_HI)
#define HPTE_V_1TB_SEG ASM_CONST(0x4000000000000000) diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 3ba571d..209f127 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -203,6 +203,12 @@ static inline int vma_pkey(struct vm_area_struct *vma) { return 0; } + +static inline u64 pte_to_hpte_pkey_bits(u64 pteflags) +{ + return 0x0UL; +} + #endif /* CONFIG_PPC_MEM_KEYS */
#endif /* __KERNEL__ */ diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index f65dedd..523d66c 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -73,6 +73,15 @@ static inline int vma_pkey(struct vm_area_struct *vma)
#define arch_max_pkey() pkeys_total
+static inline u64 pte_to_hpte_pkey_bits(u64 pteflags) +{ + return (((pteflags & H_PTE_PKEY_BIT0) ? HPTE_R_KEY_BIT0 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT1) ? HPTE_R_KEY_BIT1 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT2) ? HPTE_R_KEY_BIT2 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT3) ? HPTE_R_KEY_BIT3 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL)); +} + #define pkey_alloc_mask(pkey) (0x1 << pkey)
#define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map) diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 8bd841a..dc0f76e 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -233,6 +233,7 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags) */ rflags |= HPTE_R_M;
+ rflags |= pte_to_hpte_pkey_bits(pteflags); return rflags; }
helper function that checks if the read/write/execute is allowed on the pte.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/book3s/64/pgtable.h | 4 +++ arch/powerpc/include/asm/pkeys.h | 9 ++++++++ arch/powerpc/mm/pkeys.c | 28 ++++++++++++++++++++++++++ 3 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index e1a8bb6..e785c68 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -462,6 +462,10 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 1); }
+#ifdef CONFIG_PPC_MEM_KEYS +extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute); +#endif /* CONFIG_PPC_MEM_KEYS */ + #define __HAVE_ARCH_PTEP_GET_AND_CLEAR static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 523d66c..7c45a40 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -82,6 +82,15 @@ static inline u64 pte_to_hpte_pkey_bits(u64 pteflags) ((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL)); }
+static inline u16 pte_to_pkey_bits(u64 pteflags) +{ + return (((pteflags & H_PTE_PKEY_BIT0) ? 0x10 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT1) ? 0x8 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT2) ? 0x4 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT3) ? 0x2 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT4) ? 0x1 : 0x0UL)); +} + #define pkey_alloc_mask(pkey) (0x1 << pkey)
#define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map) diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 7630c2f..0e044ea 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -362,3 +362,31 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, /* Nothing to override. */ return vma_pkey(vma); } + +static bool pkey_access_permitted(int pkey, bool write, bool execute) +{ + int pkey_shift; + u64 amr; + + if (!pkey) + return true; + + if (!is_pkey_enabled(pkey)) + return true; + + pkey_shift = pkeyshift(pkey); + if (execute && !(read_iamr() & (IAMR_EX_BIT << pkey_shift))) + return true; + + amr = read_amr(); /* Delay reading amr until absolutely needed */ + return ((!write && !(amr & (AMR_RD_BIT << pkey_shift))) || + (write && !(amr & (AMR_WR_BIT << pkey_shift)))); +} + +bool arch_pte_access_permitted(u64 pte, bool write, bool execute) +{ + if (static_branch_likely(&pkey_disabled)) + return true; + + return pkey_access_permitted(pte_to_pkey_bits(pte), write, execute); +}
Make sure that the kernel does not access user pages without checking their key-protection.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/book3s/64/pgtable.h | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index e785c68..3d8186e 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -464,6 +464,25 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
#ifdef CONFIG_PPC_MEM_KEYS extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute); + +#define pte_access_permitted(pte, write) \ + (pte_present(pte) && \ + ((!(write) || pte_write(pte)) && \ + arch_pte_access_permitted(pte_val(pte), !!write, 0))) + +/* + * We store key in pmd/pud for huge pages. Need to check for key protection. + */ +#define pmd_access_permitted(pmd, write) \ + (pmd_present(pmd) && \ + ((!(write) || pmd_write(pmd)) && \ + arch_pte_access_permitted(pmd_val(pmd), !!write, 0))) + +#define pud_access_permitted(pud, write) \ + (pud_present(pud) && \ + ((!(write) || pud_write(pud)) && \ + arch_pte_access_permitted(pud_val(pud), !!write, 0))) + #endif /* CONFIG_PPC_MEM_KEYS */
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
This patch provides the implementation for arch_vma_access_permitted(). Returns true if the requested access is allowed by pkey associated with the vma.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/mmu_context.h | 5 +++- arch/powerpc/mm/pkeys.c | 34 ++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 209f127..cd2bd73 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -186,6 +186,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, { }
+#ifdef CONFIG_PPC_MEM_KEYS +bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write, + bool execute, bool foreign); +#else /* CONFIG_PPC_MEM_KEYS */ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write, bool execute, bool foreign) { @@ -193,7 +197,6 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, return true; }
-#ifndef CONFIG_PPC_MEM_KEYS #define pkey_mm_init(mm) #define thread_pkey_regs_save(thread) #define thread_pkey_regs_restore(new_thread, old_thread) diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 0e044ea..0701aa3 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -390,3 +390,37 @@ bool arch_pte_access_permitted(u64 pte, bool write, bool execute)
return pkey_access_permitted(pte_to_pkey_bits(pte), write, execute); } + +/* + * We only want to enforce protection keys on the current thread because we + * effectively have no access to AMR/IAMR for other threads or any way to tell + * which AMR/IAMR in a threaded process we could use. + * + * So do not enforce things if the VMA is not from the current mm, or if we are + * in a kernel thread. + */ +static inline bool vma_is_foreign(struct vm_area_struct *vma) +{ + if (!current->mm) + return true; + + /* if it is not our ->mm, it has to be foreign */ + if (current->mm != vma->vm_mm) + return true; + + return false; +} + +bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write, + bool execute, bool foreign) +{ + if (static_branch_likely(&pkey_disabled)) + return true; + /* + * Do not enforce our key-permissions on a foreign vma. + */ + if (foreign || vma_is_foreign(vma)) + return true; + + return pkey_access_permitted(vma_pkey(vma), write, execute); +}
Handle Data and Instruction exceptions caused by memory protection-key.
The CPU will detect the key fault if the HPTE is already programmed with the key.
However if the HPTE is not hashed, a key fault will not be detected by the hardware. The software will detect pkey violation in such a case.
Signed-off-by: Ram Pai linuxram@us.ibm.com Signed-off-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com --- arch/powerpc/include/asm/reg.h | 1 - arch/powerpc/kernel/exceptions-64s.S | 2 +- arch/powerpc/mm/fault.c | 22 ++++++++++++++++++++++ 3 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index b779f3c..ffc9990 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -312,7 +312,6 @@ DSISR_BAD_EXT_CTRL) #define DSISR_BAD_FAULT_64S (DSISR_BAD_FAULT_32S | \ DSISR_ATTR_CONFLICT | \ - DSISR_KEYFAULT | \ DSISR_UNSUPP_MMU | \ DSISR_PRTABLE_FAULT | \ DSISR_ICSWX_NO_CT | \ diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index e441b46..804e804 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1521,7 +1521,7 @@ USE_TEXT_SECTION() .balign IFETCH_ALIGN_BYTES do_hash_page: #ifdef CONFIG_PPC_BOOK3S_64 - lis r0,(DSISR_BAD_FAULT_64S|DSISR_DABRMATCH)@h + lis r0,(DSISR_BAD_FAULT_64S | DSISR_DABRMATCH | DSISR_KEYFAULT)@h ori r0,r0,DSISR_BAD_FAULT_64S@l and. r0,r4,r0 /* weird error? */ bne- handle_page_fault /* if not, try to insert a HPTE */ diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 4797d08..943a91e 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -427,6 +427,11 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+ if (error_code & DSISR_KEYFAULT) { + _exception(SIGSEGV, regs, SEGV_PKUERR, address); + return 0; + } + /* * We want to do this outside mmap_sem, because reading code around nip * can result in fault, which will cause a deadlock when called with @@ -498,6 +503,23 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, * the fault. */ fault = handle_mm_fault(vma, address, flags); + +#ifdef CONFIG_PPC_MEM_KEYS + /* + * if the HPTE is not hashed, hardware will not detect + * a key fault. Lets check if we failed because of a + * software detected key fault. + */ + if (unlikely(fault & VM_FAULT_SIGSEGV) && + !arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, + is_exec, 0)) { + int pkey = vma_pkey(vma); + + if (likely(pkey)) + return __bad_area(regs, address, SEGV_PKUERR); + } +#endif /* CONFIG_PPC_MEM_KEYS */ + major |= fault & VM_FAULT_MAJOR;
/*
get_mm_addr_key() helper returns the pkey associated with an address corresponding to a given mm_struct.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/mmu.h | 9 +++++++++ arch/powerpc/mm/hash_utils_64.c | 24 ++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h index 6364f5c..bb38312 100644 --- a/arch/powerpc/include/asm/mmu.h +++ b/arch/powerpc/include/asm/mmu.h @@ -260,6 +260,15 @@ static inline bool early_radix_enabled(void) } #endif
+#ifdef CONFIG_PPC_MEM_KEYS +extern u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address); +#else +static inline u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address) +{ + return 0; +} +#endif /* CONFIG_PPC_MEM_KEYS */ + #endif /* !__ASSEMBLY__ */
/* The kernel use the constants below to index in the page sizes array. diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index dc0f76e..1e1c03b 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -1573,6 +1573,30 @@ void hash_preload(struct mm_struct *mm, unsigned long ea, local_irq_restore(flags); }
+#ifdef CONFIG_PPC_MEM_KEYS +/* + * Return the protection key associated with the given address and the + * mm_struct. + */ +u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address) +{ + pte_t *ptep; + u16 pkey = 0; + unsigned long flags; + + if (!mm || !mm->pgd) + return 0; + + local_irq_save(flags); + ptep = find_linux_pte(mm->pgd, address, NULL, NULL); + if (ptep) + pkey = pte_to_pkey_bits(pte_val(READ_ONCE(*ptep))); + local_irq_restore(flags); + + return pkey; +} +#endif /* CONFIG_PPC_MEM_KEYS */ + #ifdef CONFIG_PPC_TRANSACTIONAL_MEM static inline void tm_flush_hash_page(int local) {
The value of the pkey, whose protection got violated, is made available in si_pkey field of the siginfo structure.
Signed-off-by: Ram Pai linuxram@us.ibm.com Signed-off-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com --- arch/powerpc/include/asm/bug.h | 1 + arch/powerpc/kernel/traps.c | 12 +++++++++++- arch/powerpc/mm/fault.c | 39 +++++++++++++++++++++++++++------------ 3 files changed, 39 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index 3c04249..97c3847 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -133,6 +133,7 @@ extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long); extern void bad_page_fault(struct pt_regs *, unsigned long, int); extern void _exception(int, struct pt_regs *, int, unsigned long); +extern void _exception_pkey(int, struct pt_regs *, int, unsigned long, int); extern void die(const char *, struct pt_regs *, long); extern bool die_will_crash(void);
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index f3eb61b..3753498 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -20,6 +20,7 @@ #include <linux/sched/debug.h> #include <linux/kernel.h> #include <linux/mm.h> +#include <linux/pkeys.h> #include <linux/stddef.h> #include <linux/unistd.h> #include <linux/ptrace.h> @@ -266,7 +267,9 @@ void user_single_step_siginfo(struct task_struct *tsk, info->si_addr = (void __user *)regs->nip; }
-void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr) + +void _exception_pkey(int signr, struct pt_regs *regs, int code, + unsigned long addr, int key) { siginfo_t info; const char fmt32[] = KERN_INFO "%s[%d]: unhandled signal %d " \ @@ -293,9 +296,16 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr) info.si_signo = signr; info.si_code = code; info.si_addr = (void __user *) addr; + info.si_pkey = key; + force_sig_info(signr, &info, current); }
+void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr) +{ + _exception_pkey(signr, regs, code, addr, 0); +} + void system_reset_exception(struct pt_regs *regs) { /* diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 943a91e..65f8b04 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -107,7 +107,8 @@ static bool store_updates_sp(struct pt_regs *regs) */
static int -__bad_area_nosemaphore(struct pt_regs *regs, unsigned long address, int si_code) +__bad_area_nosemaphore(struct pt_regs *regs, unsigned long address, int si_code, + int pkey) { /* * If we are in kernel mode, bail out with a SEGV, this will @@ -117,17 +118,18 @@ static bool store_updates_sp(struct pt_regs *regs) if (!user_mode(regs)) return SIGSEGV;
- _exception(SIGSEGV, regs, si_code, address); + _exception_pkey(SIGSEGV, regs, si_code, address, pkey);
return 0; }
static noinline int bad_area_nosemaphore(struct pt_regs *regs, unsigned long address) { - return __bad_area_nosemaphore(regs, address, SEGV_MAPERR); + return __bad_area_nosemaphore(regs, address, SEGV_MAPERR, 0); }
-static int __bad_area(struct pt_regs *regs, unsigned long address, int si_code) +static int __bad_area(struct pt_regs *regs, unsigned long address, int si_code, + int pkey) { struct mm_struct *mm = current->mm;
@@ -137,12 +139,18 @@ static int __bad_area(struct pt_regs *regs, unsigned long address, int si_code) */ up_read(&mm->mmap_sem);
- return __bad_area_nosemaphore(regs, address, si_code); + return __bad_area_nosemaphore(regs, address, si_code, pkey); }
static noinline int bad_area(struct pt_regs *regs, unsigned long address) { - return __bad_area(regs, address, SEGV_MAPERR); + return __bad_area(regs, address, SEGV_MAPERR, 0); +} + +static int bad_key_fault_exception(struct pt_regs *regs, unsigned long address, + int pkey) +{ + return __bad_area_nosemaphore(regs, address, SEGV_PKUERR, pkey); }
static int do_sigbus(struct pt_regs *regs, unsigned long address, @@ -427,10 +435,9 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
- if (error_code & DSISR_KEYFAULT) { - _exception(SIGSEGV, regs, SEGV_PKUERR, address); - return 0; - } + if (error_code & DSISR_KEYFAULT) + return bad_key_fault_exception(regs, address, + get_mm_addr_key(mm, address));
/* * We want to do this outside mmap_sem, because reading code around nip @@ -513,10 +520,18 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, if (unlikely(fault & VM_FAULT_SIGSEGV) && !arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, is_exec, 0)) { + /* + * The PGD-PDT...PMD-PTE tree may not have been fully setup. + * Hence we cannot walk the tree to locate the PTE, to locate + * the key. Hence let's use vma_pkey() to get the key; instead + * of get_mm_addr_key(). + */ int pkey = vma_pkey(vma);
- if (likely(pkey)) - return __bad_area(regs, address, SEGV_PKUERR); + if (likely(pkey)) { + up_read(&mm->mmap_sem); + return bad_key_fault_exception(regs, address, pkey); + } } #endif /* CONFIG_PPC_MEM_KEYS */
From: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com
The AMR/IAMR/UAMOR are part of the program context. Allow it to be accessed via ptrace and through core files.
Signed-off-by: Ram Pai linuxram@us.ibm.com Signed-off-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com --- arch/powerpc/include/asm/pkeys.h | 5 +++ arch/powerpc/include/uapi/asm/elf.h | 1 + arch/powerpc/kernel/ptrace.c | 66 +++++++++++++++++++++++++++++++++++ arch/powerpc/kernel/traps.c | 7 ++++ include/uapi/linux/elf.h | 1 + 5 files changed, 80 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 7c45a40..0c480b2 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -213,6 +213,11 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, return __arch_set_user_pkey_access(tsk, pkey, init_val); }
+static inline bool arch_pkeys_enabled(void) +{ + return !static_branch_likely(&pkey_disabled); +} + extern void pkey_mm_init(struct mm_struct *mm); extern void thread_pkey_regs_save(struct thread_struct *thread); extern void thread_pkey_regs_restore(struct thread_struct *new_thread, diff --git a/arch/powerpc/include/uapi/asm/elf.h b/arch/powerpc/include/uapi/asm/elf.h index 5f201d4..860c592 100644 --- a/arch/powerpc/include/uapi/asm/elf.h +++ b/arch/powerpc/include/uapi/asm/elf.h @@ -97,6 +97,7 @@ #define ELF_NTMSPRREG 3 /* include tfhar, tfiar, texasr */ #define ELF_NEBB 3 /* includes ebbrr, ebbhr, bescr */ #define ELF_NPMU 5 /* includes siar, sdar, sier, mmcr2, mmcr0 */ +#define ELF_NPKEY 3 /* includes amr, iamr, uamor */
typedef unsigned long elf_greg_t64; typedef elf_greg_t64 elf_gregset_t64[ELF_NGREG]; diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index f52ad5b..3718a04 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -35,6 +35,7 @@ #include <linux/context_tracking.h>
#include <linux/uaccess.h> +#include <linux/pkeys.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/switch_to.h> @@ -1775,6 +1776,61 @@ static int pmu_set(struct task_struct *target, return ret; } #endif + +#ifdef CONFIG_PPC_MEM_KEYS +static int pkey_active(struct task_struct *target, + const struct user_regset *regset) +{ + if (!arch_pkeys_enabled()) + return -ENODEV; + + return regset->n; +} + +static int pkey_get(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + void *kbuf, void __user *ubuf) +{ + BUILD_BUG_ON(TSO(amr) + sizeof(unsigned long) != TSO(iamr)); + BUILD_BUG_ON(TSO(iamr) + sizeof(unsigned long) != TSO(uamor)); + + if (!arch_pkeys_enabled()) + return -ENODEV; + + return user_regset_copyout(&pos, &count, &kbuf, &ubuf, + &target->thread.amr, 0, + ELF_NPKEY * sizeof(unsigned long)); +} + +static int pkey_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + u64 new_amr; + int ret; + + if (!arch_pkeys_enabled()) + return -ENODEV; + + /* Only the AMR can be set from userspace */ + if (pos != 0 || count != sizeof(new_amr)) + return -EINVAL; + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + &new_amr, 0, sizeof(new_amr)); + if (ret) + return ret; + + /* UAMOR determines which bits of the AMR can be set from userspace. */ + target->thread.amr = (new_amr & target->thread.uamor) | + (target->thread.amr & ~target->thread.uamor); + + return 0; +} +#endif /* CONFIG_PPC_MEM_KEYS */ + /* * These are our native regset flavors. */ @@ -1809,6 +1865,9 @@ enum powerpc_regset { REGSET_EBB, /* EBB registers */ REGSET_PMR, /* Performance Monitor Registers */ #endif +#ifdef CONFIG_PPC_MEM_KEYS + REGSET_PKEY, /* AMR register */ +#endif };
static const struct user_regset native_regsets[] = { @@ -1914,6 +1973,13 @@ enum powerpc_regset { .active = pmu_active, .get = pmu_get, .set = pmu_set }, #endif +#ifdef CONFIG_PPC_MEM_KEYS + [REGSET_PKEY] = { + .core_note_type = NT_PPC_PKEY, .n = ELF_NPKEY, + .size = sizeof(u64), .align = sizeof(u64), + .active = pkey_active, .get = pkey_get, .set = pkey_set + }, +#endif };
static const struct user_regset_view user_ppc_native_view = { diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 3753498..c42ca5b 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -292,6 +292,13 @@ void _exception_pkey(int signr, struct pt_regs *regs, int code, local_irq_enable();
current->thread.trap_nr = code; + + /* + * Save all the pkey registers AMR/IAMR/UAMOR. Eg: Core dumps need + * to capture the content, if the task gets killed. + */ + thread_pkey_regs_save(¤t->thread); + memset(&info, 0, sizeof(info)); info.si_signo = signr; info.si_code = code; diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index bb68369..3bf73fb 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -396,6 +396,7 @@ #define NT_PPC_TM_CTAR 0x10d /* TM checkpointed Target Address Register */ #define NT_PPC_TM_CPPR 0x10e /* TM checkpointed Program Priority Register */ #define NT_PPC_TM_CDSCR 0x10f /* TM checkpointed Data Stream Control Register */ +#define NT_PPC_PKEY 0x110 /* Memory Protection Keys registers */ #define NT_386_TLS 0x200 /* i386 TLS slots (struct user_desc) */ #define NT_386_IOPERM 0x201 /* x86 io permission bitmap (1=deny) */ #define NT_X86_XSTATE 0x202 /* x86 extended state using xsave */
PAPR defines 'ibm,processor-storage-keys' property. It exports two values. The first value holds the number of data-access keys and the second holds the number of instruction-access keys. Due to a bug in the firmware, instruction-access keys is always reported as zero. However any key can be configured to disable data-access and/or disable execution-access. The inavailablity of the second value is not a big handicap, though it could have been used to determine if the platform supported disable-execution-access.
Non-PAPR platforms do not define this property in the device tree yet. Fortunately power8 is the only released Non-PAPR platform that is supported. Here, we hardcode the number of supported pkey to 32, by consulting the PowerISA3.0
This patch calculates the number of keys supported by the platform. Also it determines the platform support for read/write/execution access support for pkeys.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/cputable.h | 16 ++++++--- arch/powerpc/include/asm/pkeys.h | 3 ++ arch/powerpc/mm/pkeys.c | 61 +++++++++++++++++++++++++++++----- 3 files changed, 65 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h index 0546663..5b54337 100644 --- a/arch/powerpc/include/asm/cputable.h +++ b/arch/powerpc/include/asm/cputable.h @@ -207,7 +207,7 @@ enum { #define CPU_FTR_STCX_CHECKS_ADDRESS LONG_ASM_CONST(0x0004000000000000) #define CPU_FTR_POPCNTB LONG_ASM_CONST(0x0008000000000000) #define CPU_FTR_POPCNTD LONG_ASM_CONST(0x0010000000000000) -/* Free LONG_ASM_CONST(0x0020000000000000) */ +#define CPU_FTR_PKEY LONG_ASM_CONST(0x0020000000000000) #define CPU_FTR_VMX_COPY LONG_ASM_CONST(0x0040000000000000) #define CPU_FTR_TM LONG_ASM_CONST(0x0080000000000000) #define CPU_FTR_CFAR LONG_ASM_CONST(0x0100000000000000) @@ -215,6 +215,7 @@ enum { #define CPU_FTR_DAWR LONG_ASM_CONST(0x0400000000000000) #define CPU_FTR_DABRX LONG_ASM_CONST(0x0800000000000000) #define CPU_FTR_PMAO_BUG LONG_ASM_CONST(0x1000000000000000) +#define CPU_FTR_PKEY_EXECUTE LONG_ASM_CONST(0x2000000000000000) #define CPU_FTR_POWER9_DD1 LONG_ASM_CONST(0x4000000000000000) #define CPU_FTR_POWER9_DD2_1 LONG_ASM_CONST(0x8000000000000000)
@@ -437,7 +438,8 @@ enum { CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ CPU_FTR_MMCRA | CPU_FTR_SMT | \ CPU_FTR_COHERENT_ICACHE | CPU_FTR_PURR | \ - CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_DABRX) + CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_DABRX | \ + CPU_FTR_PKEY) #define CPU_FTRS_POWER6 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ CPU_FTR_MMCRA | CPU_FTR_SMT | \ @@ -445,7 +447,7 @@ enum { CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \ CPU_FTR_DSCR | CPU_FTR_UNALIGNED_LD_STD | \ CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_CFAR | \ - CPU_FTR_DABRX) + CPU_FTR_DABRX | CPU_FTR_PKEY) #define CPU_FTRS_POWER7 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | CPU_FTR_ARCH_206 |\ CPU_FTR_MMCRA | CPU_FTR_SMT | \ @@ -454,7 +456,7 @@ enum { CPU_FTR_DSCR | CPU_FTR_SAO | CPU_FTR_ASYM_SMT | \ CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \ CPU_FTR_CFAR | CPU_FTR_HVMODE | \ - CPU_FTR_VMX_COPY | CPU_FTR_HAS_PPR | CPU_FTR_DABRX) + CPU_FTR_VMX_COPY | CPU_FTR_HAS_PPR | CPU_FTR_DABRX | CPU_FTR_PKEY) #define CPU_FTRS_POWER8 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | CPU_FTR_ARCH_206 |\ CPU_FTR_MMCRA | CPU_FTR_SMT | \ @@ -464,7 +466,8 @@ enum { CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \ CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \ CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_DAWR | \ - CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP) + CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP | CPU_FTR_PKEY |\ + CPU_FTR_PKEY_EXECUTE) #define CPU_FTRS_POWER8E (CPU_FTRS_POWER8 | CPU_FTR_PMAO_BUG) #define CPU_FTRS_POWER8_DD1 (CPU_FTRS_POWER8 & ~CPU_FTR_DBELL) #define CPU_FTRS_POWER9 (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ @@ -476,7 +479,8 @@ enum { CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \ CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \ CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_DAWR | \ - CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP | CPU_FTR_ARCH_300) + CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | \ + CPU_FTR_PKEY | CPU_FTR_PKEY_EXECUTE) #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \ (~CPU_FTR_SAO)) #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9 diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 0c480b2..92b6776 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -13,6 +13,7 @@ #define _ASM_POWERPC_KEYS_H
#include <linux/jump_label.h> +#include <asm/firmware.h>
DECLARE_STATIC_KEY_TRUE(pkey_disabled); extern int pkeys_total; /* total pkeys as per device tree */ @@ -219,6 +220,8 @@ static inline bool arch_pkeys_enabled(void) }
extern void pkey_mm_init(struct mm_struct *mm); +extern bool arch_supports_pkeys(int cap); +extern unsigned int arch_usable_pkeys(void); extern void thread_pkey_regs_save(struct thread_struct *thread); extern void thread_pkey_regs_restore(struct thread_struct *new_thread, struct thread_struct *old_thread); diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 0701aa3..66a1091 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -10,11 +10,14 @@ */
#include <asm/mman.h> +#include <asm/setup.h> #include <linux/pkeys.h> +#include <linux/of_device.h>
DEFINE_STATIC_KEY_TRUE(pkey_disabled); bool pkey_execute_disable_supported; int pkeys_total; /* Total pkeys as per device tree */ +bool pkeys_devtree_defined; /* pkey property exported by device tree */ u32 initial_allocation_mask; /* Bits set for reserved keys */ u64 pkey_amr_uamor_mask; /* Bits in AMR/UMOR not to be touched */ u64 pkey_iamr_mask; /* Bits in AMR not to be touched */ @@ -26,6 +29,35 @@ #define PKEY_REG_BITS (sizeof(u64)*8) #define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey+1) * AMR_BITS_PER_PKEY))
+static void scan_pkey_feature(void) +{ + u32 vals[2]; + struct device_node *cpu; + + cpu = of_find_node_by_type(NULL, "cpu"); + if (!cpu) + return; + + if (of_property_read_u32_array(cpu, + "ibm,processor-storage-keys", vals, 2)) + return; + + /* + * Since any pkey can be used for data or execute, we will just treat + * all keys as equal and track them as one entity. + */ + pkeys_total = be32_to_cpu(vals[0]); + pkeys_devtree_defined = true; +} + +static inline bool pkey_mmu_enabled(void) +{ + if (firmware_has_feature(FW_FEATURE_LPAR)) + return pkeys_total; + else + return cpu_has_feature(CPU_FTR_PKEY); +} + int pkey_initialize(void) { int os_reserved, i; @@ -46,14 +78,17 @@ int pkey_initialize(void) __builtin_popcountl(ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT) != (sizeof(u64) * BITS_PER_BYTE));
+ /* scan the device tree for pkey feature */ + scan_pkey_feature(); + /* - * Disable the pkey system till everything is in place. A subsequent - * patch will enable it. + * Let's assume 32 pkeys on P8 bare metal, if its not defined by device + * tree. We make this exception since skiboot forgot to expose this + * property on power8. */ - static_branch_enable(&pkey_disabled); - - /* Lets assume 32 keys */ - pkeys_total = 32; + if (!pkeys_devtree_defined && !firmware_has_feature(FW_FEATURE_LPAR) && + cpu_has_feature(CPU_FTRS_POWER8)) + pkeys_total = 32;
/* * Adjust the upper limit, based on the number of bits supported by @@ -62,11 +97,19 @@ int pkey_initialize(void) pkeys_total = min_t(int, pkeys_total, (ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT));
+ if (!pkey_mmu_enabled() || radix_enabled() || !pkeys_total) + static_branch_enable(&pkey_disabled); + else + static_branch_disable(&pkey_disabled); + + if (static_branch_likely(&pkey_disabled)) + return 0; + /* - * Disable execute_disable support for now. A subsequent patch will - * enable it. + * The device tree cannot be relied on for execute_disable support. + * Hence we depend on CPU FTR. */ - pkey_execute_disable_supported = false; + pkey_execute_disable_supported = cpu_has_feature(CPU_FTR_PKEY_EXECUTE);
#ifdef CONFIG_PPC_4K_PAGES /*
Finally this patch provides the ability for a process to allocate and free a protection key.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/systbl.h | 2 ++ arch/powerpc/include/asm/unistd.h | 4 +--- arch/powerpc/include/uapi/asm/unistd.h | 2 ++ 3 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h index 449912f..dea4a95 100644 --- a/arch/powerpc/include/asm/systbl.h +++ b/arch/powerpc/include/asm/systbl.h @@ -389,3 +389,5 @@ COMPAT_SYS_SPU(pwritev2) SYSCALL(kexec_file_load) SYSCALL(statx) +SYSCALL(pkey_alloc) +SYSCALL(pkey_free) diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h index 9ba11db..e0273bc 100644 --- a/arch/powerpc/include/asm/unistd.h +++ b/arch/powerpc/include/asm/unistd.h @@ -12,13 +12,11 @@ #include <uapi/asm/unistd.h>
-#define NR_syscalls 384 +#define NR_syscalls 386
#define __NR__exit __NR_exit
#define __IGNORE_pkey_mprotect -#define __IGNORE_pkey_alloc -#define __IGNORE_pkey_free
#ifndef __ASSEMBLY__
diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h index df8684f..5db4385 100644 --- a/arch/powerpc/include/uapi/asm/unistd.h +++ b/arch/powerpc/include/uapi/asm/unistd.h @@ -395,5 +395,7 @@ #define __NR_pwritev2 381 #define __NR_kexec_file_load 382 #define __NR_statx 383 +#define __NR_pkey_alloc 384 +#define __NR_pkey_free 385
#endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */
Patch provides the ability for a process to associate a pkey with a address range.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/systbl.h | 1 + arch/powerpc/include/asm/unistd.h | 4 +--- arch/powerpc/include/uapi/asm/unistd.h | 1 + 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h index dea4a95..d61f9c9 100644 --- a/arch/powerpc/include/asm/systbl.h +++ b/arch/powerpc/include/asm/systbl.h @@ -391,3 +391,4 @@ SYSCALL(statx) SYSCALL(pkey_alloc) SYSCALL(pkey_free) +SYSCALL(pkey_mprotect) diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h index e0273bc..daf1ba9 100644 --- a/arch/powerpc/include/asm/unistd.h +++ b/arch/powerpc/include/asm/unistd.h @@ -12,12 +12,10 @@ #include <uapi/asm/unistd.h>
-#define NR_syscalls 386 +#define NR_syscalls 387
#define __NR__exit __NR_exit
-#define __IGNORE_pkey_mprotect - #ifndef __ASSEMBLY__
#include <linux/types.h> diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h index 5db4385..389c36f 100644 --- a/arch/powerpc/include/uapi/asm/unistd.h +++ b/arch/powerpc/include/uapi/asm/unistd.h @@ -397,5 +397,6 @@ #define __NR_statx 383 #define __NR_pkey_alloc 384 #define __NR_pkey_free 385 +#define __NR_pkey_mprotect 386
#endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */
Arch neutral code needs to know if the architecture supports protection keys to display protection key in smaps. Hence introducing arch_pkeys_enabled().
This patch also provides x86 implementation for arch_pkeys_enabled().
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/x86/include/asm/pkeys.h | 1 + arch/x86/kernel/fpu/xstate.c | 5 +++++ include/linux/pkeys.h | 5 +++++ 3 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h index a0ba1ff..f6c287b 100644 --- a/arch/x86/include/asm/pkeys.h +++ b/arch/x86/include/asm/pkeys.h @@ -6,6 +6,7 @@
extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val); +extern bool arch_pkeys_enabled(void);
/* * Try to dedicate one of the protection keys to be used as an diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 87a57b7..4f566e9 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -945,6 +945,11 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
return 0; } + +bool arch_pkeys_enabled(void) +{ + return boot_cpu_has(X86_FEATURE_OSPKE); +} #endif /* ! CONFIG_ARCH_HAS_PKEYS */
/* diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h index 0794ca7..3ca2e44 100644 --- a/include/linux/pkeys.h +++ b/include/linux/pkeys.h @@ -35,6 +35,11 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, return 0; }
+static inline bool arch_pkeys_enabled(void) +{ + return false; +} + static inline void copy_init_pkru_to_fpregs(void) { }
Currently the architecture specific code is expected to display the protection keys in smap for a given vma. This can lead to redundant code and possibly to divergent formats in which the key gets displayed.
This patch changes the implementation. It displays the pkey only if the architecture support pkeys.
x86 arch_show_smap() function is not needed anymore. Delete it.
Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/x86/kernel/setup.c | 8 -------- fs/proc/task_mmu.c | 11 ++++++----- 2 files changed, 6 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 8af2e8d..ddf945a 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1326,11 +1326,3 @@ static int __init register_kernel_offset_dumper(void) return 0; } __initcall(register_kernel_offset_dumper); - -void arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{ - if (!boot_cpu_has(X86_FEATURE_OSPKE)) - return; - - seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma)); -} diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 0edd4da..4b39a94 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -18,6 +18,7 @@ #include <linux/page_idle.h> #include <linux/shmem_fs.h> #include <linux/uaccess.h> +#include <linux/pkeys.h>
#include <asm/elf.h> #include <asm/tlb.h> @@ -728,10 +729,6 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, } #endif /* HUGETLB_PAGE */
-void __weak arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{ -} - static int show_smap(struct seq_file *m, void *v, int is_pid) { struct proc_maps_private *priv = m->private; @@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));
if (!rollup_mode) { - arch_show_smap(m, vma); +#ifdef CONFIG_ARCH_HAS_PKEYS + if (arch_pkeys_enabled()) + seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma)); +#endif show_smap_vma_flags(m, vma); } + m_cache_vma(m, vma); return ret; }
Ram Pai linuxram@us.ibm.com writes:
Currently the architecture specific code is expected to display the protection keys in smap for a given vma. This can lead to redundant code and possibly to divergent formats in which the key gets displayed.
This patch changes the implementation. It displays the pkey only if the architecture support pkeys.
x86 arch_show_smap() function is not needed anymore. Delete it.
Signed-off-by: Ram Pai linuxram@us.ibm.com
arch/x86/kernel/setup.c | 8 -------- fs/proc/task_mmu.c | 11 ++++++----- 2 files changed, 6 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 8af2e8d..ddf945a 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1326,11 +1326,3 @@ static int __init register_kernel_offset_dumper(void) return 0; } __initcall(register_kernel_offset_dumper);
-void arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{
- if (!boot_cpu_has(X86_FEATURE_OSPKE))
return;
- seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
-} diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 0edd4da..4b39a94 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -18,6 +18,7 @@ #include <linux/page_idle.h> #include <linux/shmem_fs.h> #include <linux/uaccess.h> +#include <linux/pkeys.h> #include <asm/elf.h> #include <asm/tlb.h> @@ -728,10 +729,6 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, } #endif /* HUGETLB_PAGE */ -void __weak arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{ -}
static int show_smap(struct seq_file *m, void *v, int is_pid) { struct proc_maps_private *priv = m->private; @@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) (unsigned long)(mss->pss >> (10 + PSS_SHIFT))); if (!rollup_mode) {
arch_show_smap(m, vma);
+#ifdef CONFIG_ARCH_HAS_PKEYS
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
+#endif
Would it be worth it making vma_pkey a noop on architectures that don't support protection keys so that we don't need the #ifdef here?
Eric
show_smap_vma_flags(m, vma);
}
- m_cache_vma(m, vma); return ret;
}
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On Fri, Jan 19, 2018 at 10:09:41AM -0600, Eric W. Biederman wrote:
Ram Pai linuxram@us.ibm.com writes:
Currently the architecture specific code is expected to display the protection keys in smap for a given vma. This can lead to redundant code and possibly to divergent formats in which the key gets displayed.
This patch changes the implementation. It displays the pkey only if the architecture support pkeys.
x86 arch_show_smap() function is not needed anymore. Delete it.
Signed-off-by: Ram Pai linuxram@us.ibm.com
arch/x86/kernel/setup.c | 8 -------- fs/proc/task_mmu.c | 11 ++++++----- 2 files changed, 6 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 8af2e8d..ddf945a 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1326,11 +1326,3 @@ static int __init register_kernel_offset_dumper(void) return 0; } __initcall(register_kernel_offset_dumper);
-void arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{
- if (!boot_cpu_has(X86_FEATURE_OSPKE))
return;
- seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
-} diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 0edd4da..4b39a94 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -18,6 +18,7 @@ #include <linux/page_idle.h> #include <linux/shmem_fs.h> #include <linux/uaccess.h> +#include <linux/pkeys.h> #include <asm/elf.h> #include <asm/tlb.h> @@ -728,10 +729,6 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, } #endif /* HUGETLB_PAGE */ -void __weak arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{ -}
static int show_smap(struct seq_file *m, void *v, int is_pid) { struct proc_maps_private *priv = m->private; @@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) (unsigned long)(mss->pss >> (10 + PSS_SHIFT))); if (!rollup_mode) {
arch_show_smap(m, vma);
+#ifdef CONFIG_ARCH_HAS_PKEYS
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
+#endif
Would it be worth it making vma_pkey a noop on architectures that don't support protection keys so that we don't need the #ifdef here?
You mean something like this? #define vma_pkey(vma) It will lead to compilation error.
I can make it #define vma_pkey(vma) 0
and that will work and get rid of the #ifdef
RP
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Ram Pai linuxram@us.ibm.com writes:
On Fri, Jan 19, 2018 at 10:09:41AM -0600, Eric W. Biederman wrote:
Ram Pai linuxram@us.ibm.com writes:
Currently the architecture specific code is expected to display the protection keys in smap for a given vma. This can lead to redundant code and possibly to divergent formats in which the key gets displayed.
This patch changes the implementation. It displays the pkey only if the architecture support pkeys.
x86 arch_show_smap() function is not needed anymore. Delete it.
Signed-off-by: Ram Pai linuxram@us.ibm.com
arch/x86/kernel/setup.c | 8 -------- fs/proc/task_mmu.c | 11 ++++++----- 2 files changed, 6 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 8af2e8d..ddf945a 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1326,11 +1326,3 @@ static int __init register_kernel_offset_dumper(void) return 0; } __initcall(register_kernel_offset_dumper);
-void arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{
- if (!boot_cpu_has(X86_FEATURE_OSPKE))
return;
- seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
-} diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 0edd4da..4b39a94 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -18,6 +18,7 @@ #include <linux/page_idle.h> #include <linux/shmem_fs.h> #include <linux/uaccess.h> +#include <linux/pkeys.h> #include <asm/elf.h> #include <asm/tlb.h> @@ -728,10 +729,6 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, } #endif /* HUGETLB_PAGE */ -void __weak arch_show_smap(struct seq_file *m, struct vm_area_struct *vma) -{ -}
static int show_smap(struct seq_file *m, void *v, int is_pid) { struct proc_maps_private *priv = m->private; @@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) (unsigned long)(mss->pss >> (10 + PSS_SHIFT))); if (!rollup_mode) {
arch_show_smap(m, vma);
+#ifdef CONFIG_ARCH_HAS_PKEYS
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
+#endif
Would it be worth it making vma_pkey a noop on architectures that don't support protection keys so that we don't need the #ifdef here?
You mean something like this? #define vma_pkey(vma) It will lead to compilation error.
I can make it #define vma_pkey(vma) 0
and that will work and get rid of the #ifdef
Yes the second is what I was thinking.
I don't know if it is worth it but #ifdefs can be problematic as the result in code not being compile tested.
Eric
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On Thu 18-01-18 17:50:48, Ram Pai wrote: [...]
@@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) (unsigned long)(mss->pss >> (10 + PSS_SHIFT))); if (!rollup_mode) {
arch_show_smap(m, vma);
+#ifdef CONFIG_ARCH_HAS_PKEYS
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
+#endif show_smap_vma_flags(m, vma); }
Why do you need to add ifdef here? The previous patch should make arch_pkeys_enabled == F when CONFIG_ARCH_HAS_PKEYS=n. Btw. could you merge those two patches into one. It is usually much easier to review a new helper function if it is added along with a user.
m_cache_vma(m, vma); return ret; } -- 1.7.1
On Tue, Jan 30, 2018 at 01:16:11PM +0100, Michal Hocko wrote:
On Thu 18-01-18 17:50:48, Ram Pai wrote: [...]
@@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) (unsigned long)(mss->pss >> (10 + PSS_SHIFT))); if (!rollup_mode) {
arch_show_smap(m, vma);
+#ifdef CONFIG_ARCH_HAS_PKEYS
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
+#endif show_smap_vma_flags(m, vma); }
Why do you need to add ifdef here? The previous patch should make arch_pkeys_enabled == F when CONFIG_ARCH_HAS_PKEYS=n.
You are right. it need not be wrapped in CONFIG_ARCH_HAS_PKEYS. I had to do it because vma_pkey(vma) is not defined in some architectures.
I will provide a generic vma_pkey() definition for architectures that do not support PKEYS.
Btw. could you merge those two patches into one. It is usually much easier to review a new helper function if it is added along with a user.
ok.
Thanks, RP
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