This is a note to let you know that I've just added the patch titled
x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x86-mm-kasan-don-t-use-vmemmap_populate-to-initialize-shadow.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 2aeb07365bcd489620f71390a7d2031cd4dfb83e Mon Sep 17 00:00:00 2001
From: Andrey Ryabinin aryabinin@virtuozzo.com Date: Wed, 15 Nov 2017 17:36:35 -0800 Subject: x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
From: Andrey Ryabinin aryabinin@virtuozzo.com
commit 2aeb07365bcd489620f71390a7d2031cd4dfb83e upstream.
[ Note, this is a Git cherry-pick of the following commit:
d17a1d97dc20: ("x86/mm/kasan: don't use vmemmap_populate() to initialize shadow")
... for easier x86 PTI code testing and back-porting. ]
The KASAN shadow is currently mapped using vmemmap_populate() since that provides a semi-convenient way to map pages into init_top_pgt. However, since that no longer zeroes the mapped pages, it is not suitable for KASAN, which requires zeroed shadow memory.
Add kasan_populate_shadow() interface and use it instead of vmemmap_populate(). Besides, this allows us to take advantage of gigantic pages and use them to populate the shadow, which should save us some memory wasted on page tables and reduce TLB pressure.
Link: http://lkml.kernel.org/r/20171103185147.2688-2-pasha.tatashin@oracle.com Signed-off-by: Andrey Ryabinin aryabinin@virtuozzo.com Signed-off-by: Pavel Tatashin pasha.tatashin@oracle.com Cc: Andy Lutomirski luto@kernel.org Cc: Steven Sistare steven.sistare@oracle.com Cc: Daniel Jordan daniel.m.jordan@oracle.com Cc: Bob Picco bob.picco@oracle.com Cc: Michal Hocko mhocko@suse.com Cc: Alexander Potapenko glider@google.com Cc: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: Catalin Marinas catalin.marinas@arm.com Cc: Christian Borntraeger borntraeger@de.ibm.com Cc: David S. Miller davem@davemloft.net Cc: Dmitry Vyukov dvyukov@google.com Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@redhat.com Cc: Mark Rutland mark.rutland@arm.com Cc: Matthew Wilcox willy@infradead.org Cc: Mel Gorman mgorman@techsingularity.net Cc: Michal Hocko mhocko@kernel.org Cc: Sam Ravnborg sam@ravnborg.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Will Deacon will.deacon@arm.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/Kconfig | 2 arch/x86/mm/kasan_init_64.c | 143 +++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 137 insertions(+), 8 deletions(-)
--- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -108,7 +108,7 @@ config X86 select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE select HAVE_ARCH_JUMP_LABEL - select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP + select HAVE_ARCH_KASAN if X86_64 select HAVE_ARCH_KGDB select HAVE_ARCH_KMEMCHECK select HAVE_ARCH_MMAP_RND_BITS if MMU --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -4,12 +4,14 @@ #include <linux/bootmem.h> #include <linux/kasan.h> #include <linux/kdebug.h> +#include <linux/memblock.h> #include <linux/mm.h> #include <linux/sched.h> #include <linux/sched/task.h> #include <linux/vmalloc.h>
#include <asm/e820/types.h> +#include <asm/pgalloc.h> #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/pgtable.h> @@ -18,7 +20,134 @@ extern struct range pfn_mapped[E820_MAX_
static p4d_t tmp_p4d_table[PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);
-static int __init map_range(struct range *range) +static __init void *early_alloc(size_t size, int nid) +{ + return memblock_virt_alloc_try_nid_nopanic(size, size, + __pa(MAX_DMA_ADDRESS), BOOTMEM_ALLOC_ACCESSIBLE, nid); +} + +static void __init kasan_populate_pmd(pmd_t *pmd, unsigned long addr, + unsigned long end, int nid) +{ + pte_t *pte; + + if (pmd_none(*pmd)) { + void *p; + + if (boot_cpu_has(X86_FEATURE_PSE) && + ((end - addr) == PMD_SIZE) && + IS_ALIGNED(addr, PMD_SIZE)) { + p = early_alloc(PMD_SIZE, nid); + if (p && pmd_set_huge(pmd, __pa(p), PAGE_KERNEL)) + return; + else if (p) + memblock_free(__pa(p), PMD_SIZE); + } + + p = early_alloc(PAGE_SIZE, nid); + pmd_populate_kernel(&init_mm, pmd, p); + } + + pte = pte_offset_kernel(pmd, addr); + do { + pte_t entry; + void *p; + + if (!pte_none(*pte)) + continue; + + p = early_alloc(PAGE_SIZE, nid); + entry = pfn_pte(PFN_DOWN(__pa(p)), PAGE_KERNEL); + set_pte_at(&init_mm, addr, pte, entry); + } while (pte++, addr += PAGE_SIZE, addr != end); +} + +static void __init kasan_populate_pud(pud_t *pud, unsigned long addr, + unsigned long end, int nid) +{ + pmd_t *pmd; + unsigned long next; + + if (pud_none(*pud)) { + void *p; + + if (boot_cpu_has(X86_FEATURE_GBPAGES) && + ((end - addr) == PUD_SIZE) && + IS_ALIGNED(addr, PUD_SIZE)) { + p = early_alloc(PUD_SIZE, nid); + if (p && pud_set_huge(pud, __pa(p), PAGE_KERNEL)) + return; + else if (p) + memblock_free(__pa(p), PUD_SIZE); + } + + p = early_alloc(PAGE_SIZE, nid); + pud_populate(&init_mm, pud, p); + } + + pmd = pmd_offset(pud, addr); + do { + next = pmd_addr_end(addr, end); + if (!pmd_large(*pmd)) + kasan_populate_pmd(pmd, addr, next, nid); + } while (pmd++, addr = next, addr != end); +} + +static void __init kasan_populate_p4d(p4d_t *p4d, unsigned long addr, + unsigned long end, int nid) +{ + pud_t *pud; + unsigned long next; + + if (p4d_none(*p4d)) { + void *p = early_alloc(PAGE_SIZE, nid); + + p4d_populate(&init_mm, p4d, p); + } + + pud = pud_offset(p4d, addr); + do { + next = pud_addr_end(addr, end); + if (!pud_large(*pud)) + kasan_populate_pud(pud, addr, next, nid); + } while (pud++, addr = next, addr != end); +} + +static void __init kasan_populate_pgd(pgd_t *pgd, unsigned long addr, + unsigned long end, int nid) +{ + void *p; + p4d_t *p4d; + unsigned long next; + + if (pgd_none(*pgd)) { + p = early_alloc(PAGE_SIZE, nid); + pgd_populate(&init_mm, pgd, p); + } + + p4d = p4d_offset(pgd, addr); + do { + next = p4d_addr_end(addr, end); + kasan_populate_p4d(p4d, addr, next, nid); + } while (p4d++, addr = next, addr != end); +} + +static void __init kasan_populate_shadow(unsigned long addr, unsigned long end, + int nid) +{ + pgd_t *pgd; + unsigned long next; + + addr = addr & PAGE_MASK; + end = round_up(end, PAGE_SIZE); + pgd = pgd_offset_k(addr); + do { + next = pgd_addr_end(addr, end); + kasan_populate_pgd(pgd, addr, next, nid); + } while (pgd++, addr = next, addr != end); +} + +static void __init map_range(struct range *range) { unsigned long start; unsigned long end; @@ -26,7 +155,7 @@ static int __init map_range(struct range start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start)); end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end));
- return vmemmap_populate(start, end, NUMA_NO_NODE); + kasan_populate_shadow(start, end, early_pfn_to_nid(range->start)); }
static void __init clear_pgds(unsigned long start, @@ -189,16 +318,16 @@ void __init kasan_init(void) if (pfn_mapped[i].end == 0) break;
- if (map_range(&pfn_mapped[i])) - panic("kasan: unable to allocate shadow!"); + map_range(&pfn_mapped[i]); } + kasan_populate_zero_shadow( kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), kasan_mem_to_shadow((void *)__START_KERNEL_map));
- vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext), - (unsigned long)kasan_mem_to_shadow(_end), - NUMA_NO_NODE); + kasan_populate_shadow((unsigned long)kasan_mem_to_shadow(_stext), + (unsigned long)kasan_mem_to_shadow(_end), + early_pfn_to_nid(__pa(_stext)));
kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), (void *)KASAN_SHADOW_END);
Patches currently in stable-queue which might be from aryabinin@virtuozzo.com are
queue-4.14/x86-kasan-use-the-same-shadow-offset-for-4-and-5-level-paging.patch queue-4.14/x86-kasan-64-teach-kasan-about-the-cpu_entry_area.patch queue-4.14/x86-mm-kasan-don-t-use-vmemmap_populate-to-initialize-shadow.patch