From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Subject: x86/mm/kasan: don't use vmemmap_populate() to initialize shadow 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@xxxxxxxxxx Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Steven Sistare <steven.sistare@xxxxxxxxxx> Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Cc: Bob Picco <bob.picco@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx> Cc: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Sam Ravnborg <sam@xxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/Kconfig | 2 arch/x86/mm/kasan_init_64.c | 143 ++++++++++++++++++++++++++++++++-- 2 files changed, 137 insertions(+), 8 deletions(-) diff -puN arch/x86/Kconfig~x86-mm-kasan-dont-use-vmemmap_populate-to-initialize-shadow arch/x86/Kconfig --- a/arch/x86/Kconfig~x86-mm-kasan-dont-use-vmemmap_populate-to-initialize-shadow +++ a/arch/x86/Kconfig @@ -110,7 +110,7 @@ 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_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT diff -puN arch/x86/mm/kasan_init_64.c~x86-mm-kasan-dont-use-vmemmap_populate-to-initialize-shadow arch/x86/mm/kasan_init_64.c --- a/arch/x86/mm/kasan_init_64.c~x86-mm-kasan-dont-use-vmemmap_populate-to-initialize-shadow +++ a/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); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
