From: Russell King rmk+kernel@armlinux.org.uk
[ Upstream commit 747ffc2fcf969eff9309d7f2d1d61cb8b9e1bb40 ]
Consolidate the user access assembly code to asm/uaccess-asm.h. This moves the csdb, check_uaccess, uaccess_mask_range_ptr, uaccess_enable, uaccess_disable, uaccess_save, uaccess_restore macros, and creates two new ones for exception entry and exit - uaccess_entry and uaccess_exit.
This makes the uaccess_save and uaccess_restore macros private to asm/uaccess-asm.h.
Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/include/asm/assembler.h | 75 +------------------- arch/arm/include/asm/uaccess-asm.h | 106 +++++++++++++++++++++++++++++ arch/arm/kernel/entry-armv.S | 11 +-- arch/arm/kernel/entry-header.S | 9 +-- 4 files changed, 112 insertions(+), 89 deletions(-) create mode 100644 arch/arm/include/asm/uaccess-asm.h
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 99929122dad7..3546d294d55f 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -18,11 +18,11 @@ #endif
#include <asm/ptrace.h> -#include <asm/domain.h> #include <asm/opcodes-virt.h> #include <asm/asm-offsets.h> #include <asm/page.h> #include <asm/thread_info.h> +#include <asm/uaccess-asm.h>
#define IOMEM(x) (x)
@@ -446,79 +446,6 @@ THUMB( orr \reg , \reg , #PSR_T_BIT ) .size \name , . - \name .endm
- .macro csdb -#ifdef CONFIG_THUMB2_KERNEL - .inst.w 0xf3af8014 -#else - .inst 0xe320f014 -#endif - .endm - - .macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req -#ifndef CONFIG_CPU_USE_DOMAINS - adds \tmp, \addr, #\size - 1 - sbcscc \tmp, \tmp, \limit - bcs \bad -#ifdef CONFIG_CPU_SPECTRE - movcs \addr, #0 - csdb -#endif -#endif - .endm - - .macro uaccess_mask_range_ptr, addr:req, size:req, limit:req, tmp:req -#ifdef CONFIG_CPU_SPECTRE - sub \tmp, \limit, #1 - subs \tmp, \tmp, \addr @ tmp = limit - 1 - addr - addhs \tmp, \tmp, #1 @ if (tmp >= 0) { - subshs \tmp, \tmp, \size @ tmp = limit - (addr + size) } - movlo \addr, #0 @ if (tmp < 0) addr = NULL - csdb -#endif - .endm - - .macro uaccess_disable, tmp, isb=1 -#ifdef CONFIG_CPU_SW_DOMAIN_PAN - /* - * Whenever we re-enter userspace, the domains should always be - * set appropriately. - */ - mov \tmp, #DACR_UACCESS_DISABLE - mcr p15, 0, \tmp, c3, c0, 0 @ Set domain register - .if \isb - instr_sync - .endif -#endif - .endm - - .macro uaccess_enable, tmp, isb=1 -#ifdef CONFIG_CPU_SW_DOMAIN_PAN - /* - * Whenever we re-enter userspace, the domains should always be - * set appropriately. - */ - mov \tmp, #DACR_UACCESS_ENABLE - mcr p15, 0, \tmp, c3, c0, 0 - .if \isb - instr_sync - .endif -#endif - .endm - - .macro uaccess_save, tmp -#ifdef CONFIG_CPU_SW_DOMAIN_PAN - mrc p15, 0, \tmp, c3, c0, 0 - str \tmp, [sp, #SVC_DACR] -#endif - .endm - - .macro uaccess_restore -#ifdef CONFIG_CPU_SW_DOMAIN_PAN - ldr r0, [sp, #SVC_DACR] - mcr p15, 0, r0, c3, c0, 0 -#endif - .endm - .irp c,,eq,ne,cs,cc,mi,pl,vs,vc,hi,ls,ge,lt,gt,le,hs,lo .macro ret\c, reg #if __LINUX_ARM_ARCH__ < 6 diff --git a/arch/arm/include/asm/uaccess-asm.h b/arch/arm/include/asm/uaccess-asm.h new file mode 100644 index 000000000000..d475e3e8145d --- /dev/null +++ b/arch/arm/include/asm/uaccess-asm.h @@ -0,0 +1,106 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __ASM_UACCESS_ASM_H__ +#define __ASM_UACCESS_ASM_H__ + +#include <asm/asm-offsets.h> +#include <asm/domain.h> +#include <asm/memory.h> +#include <asm/thread_info.h> + + .macro csdb +#ifdef CONFIG_THUMB2_KERNEL + .inst.w 0xf3af8014 +#else + .inst 0xe320f014 +#endif + .endm + + .macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req +#ifndef CONFIG_CPU_USE_DOMAINS + adds \tmp, \addr, #\size - 1 + sbcscc \tmp, \tmp, \limit + bcs \bad +#ifdef CONFIG_CPU_SPECTRE + movcs \addr, #0 + csdb +#endif +#endif + .endm + + .macro uaccess_mask_range_ptr, addr:req, size:req, limit:req, tmp:req +#ifdef CONFIG_CPU_SPECTRE + sub \tmp, \limit, #1 + subs \tmp, \tmp, \addr @ tmp = limit - 1 - addr + addhs \tmp, \tmp, #1 @ if (tmp >= 0) { + subshs \tmp, \tmp, \size @ tmp = limit - (addr + size) } + movlo \addr, #0 @ if (tmp < 0) addr = NULL + csdb +#endif + .endm + + .macro uaccess_disable, tmp, isb=1 +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* + * Whenever we re-enter userspace, the domains should always be + * set appropriately. + */ + mov \tmp, #DACR_UACCESS_DISABLE + mcr p15, 0, \tmp, c3, c0, 0 @ Set domain register + .if \isb + instr_sync + .endif +#endif + .endm + + .macro uaccess_enable, tmp, isb=1 +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* + * Whenever we re-enter userspace, the domains should always be + * set appropriately. + */ + mov \tmp, #DACR_UACCESS_ENABLE + mcr p15, 0, \tmp, c3, c0, 0 + .if \isb + instr_sync + .endif +#endif + .endm + + .macro uaccess_save, tmp +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + mrc p15, 0, \tmp, c3, c0, 0 + str \tmp, [sp, #SVC_DACR] +#endif + .endm + + .macro uaccess_restore +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + ldr r0, [sp, #SVC_DACR] + mcr p15, 0, r0, c3, c0, 0 +#endif + .endm + + /* + * Save the address limit on entry to a privileged exception and + * if using PAN, save and disable usermode access. + */ + .macro uaccess_entry, tsk, tmp0, tmp1, tmp2, disable + ldr \tmp0, [\tsk, #TI_ADDR_LIMIT] + mov \tmp1, #TASK_SIZE + str \tmp1, [\tsk, #TI_ADDR_LIMIT] + str \tmp0, [sp, #SVC_ADDR_LIMIT] + uaccess_save \tmp0 + .if \disable + uaccess_disable \tmp0 + .endif + .endm + + /* Restore the user access state previously saved by uaccess_entry */ + .macro uaccess_exit, tsk, tmp0, tmp1 + ldr \tmp1, [sp, #SVC_ADDR_LIMIT] + uaccess_restore + str \tmp1, [\tsk, #TI_ADDR_LIMIT] + .endm + +#endif /* __ASM_UACCESS_ASM_H__ */ diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 77f54830554c..55a47df04773 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -27,6 +27,7 @@ #include <asm/unistd.h> #include <asm/tls.h> #include <asm/system_info.h> +#include <asm/uaccess-asm.h>
#include "entry-header.S" #include <asm/entry-macro-multi.S> @@ -179,15 +180,7 @@ ENDPROC(__und_invalid) stmia r7, {r2 - r6}
get_thread_info tsk - ldr r0, [tsk, #TI_ADDR_LIMIT] - mov r1, #TASK_SIZE - str r1, [tsk, #TI_ADDR_LIMIT] - str r0, [sp, #SVC_ADDR_LIMIT] - - uaccess_save r0 - .if \uaccess - uaccess_disable r0 - .endif + uaccess_entry tsk, r0, r1, r2, \uaccess
.if \trace #ifdef CONFIG_TRACE_IRQFLAGS diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 32051ec5b33f..40db0f9188b6 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -6,6 +6,7 @@ #include <asm/asm-offsets.h> #include <asm/errno.h> #include <asm/thread_info.h> +#include <asm/uaccess-asm.h> #include <asm/v7m.h>
@ Bad Abort numbers @@ -217,9 +218,7 @@ blne trace_hardirqs_off #endif .endif - ldr r1, [sp, #SVC_ADDR_LIMIT] - uaccess_restore - str r1, [tsk, #TI_ADDR_LIMIT] + uaccess_exit tsk, r0, r1
#ifndef CONFIG_THUMB2_KERNEL @ ARM mode SVC restore @@ -263,9 +262,7 @@ @ on the stack remains correct). @ .macro svc_exit_via_fiq - ldr r1, [sp, #SVC_ADDR_LIMIT] - uaccess_restore - str r1, [tsk, #TI_ADDR_LIMIT] + uaccess_exit tsk, r0, r1 #ifndef CONFIG_THUMB2_KERNEL @ ARM mode restore mov r0, sp