4.1-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alexander Popov <alpo...@ptsecurity.com> commit 5d5aa3cfca5cf74cd928daf3674642e6004328d1 upstream. Currently KASAN shadow region page tables created without respect of physical offset (phys_base). This causes kernel halt when phys_base is not zero. So let's initialize KASAN shadow region page tables in kasan_early_init() using __pa_nodebug() which considers phys_base. This patch also separates x86_64_start_kernel() from KASAN low level details by moving kasan_map_early_shadow(init_level4_pgt) into kasan_early_init(). Remove the comment before clear_bss() which stopped bringing much profit to the code readability. Otherwise describing all the new order dependencies would be too verbose. Signed-off-by: Alexander Popov <alpo...@ptsecurity.com> Signed-off-by: Andrey Ryabinin <a.ryabi...@samsung.com> Cc: Alexander Potapenko <gli...@google.com> Cc: Andrey Konovalov <adech...@gmail.com> Cc: Borislav Petkov <b...@alien8.de> Cc: Dmitry Vyukov <dvyu...@google.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/1435828178-10975-3-git-send-email-a.ryabi...@samsung.com Signed-off-by: Ingo Molnar <mi...@kernel.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/x86/include/asm/kasan.h | 8 ++------ arch/x86/kernel/head64.c | 7 ++----- arch/x86/kernel/head_64.S | 29 ----------------------------- arch/x86/mm/kasan_init_64.c | 36 ++++++++++++++++++++++++++++++++++-- 4 files changed, 38 insertions(+), 42 deletions(-) --- a/arch/x86/include/asm/kasan.h +++ b/arch/x86/include/asm/kasan.h @@ -14,15 +14,11 @@ #ifndef __ASSEMBLY__ -extern pte_t kasan_zero_pte[]; -extern pte_t kasan_zero_pmd[]; -extern pte_t kasan_zero_pud[]; - #ifdef CONFIG_KASAN -void __init kasan_map_early_shadow(pgd_t *pgd); +void __init kasan_early_init(void); void __init kasan_init(void); #else -static inline void kasan_map_early_shadow(pgd_t *pgd) { } +static inline void kasan_early_init(void) { } static inline void kasan_init(void) { } #endif --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -161,13 +161,12 @@ asmlinkage __visible void __init x86_64_ /* Kill off the identity-map trampoline */ reset_early_page_tables(); - kasan_map_early_shadow(early_level4_pgt); - - /* clear bss before set_intr_gate with early_idt_handler */ clear_bss(); clear_page(init_level4_pgt); + kasan_early_init(); + for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) set_intr_gate(i, early_idt_handler_array[i]); load_idt((const struct desc_ptr *)&idt_descr); @@ -182,8 +181,6 @@ asmlinkage __visible void __init x86_64_ /* set init_level4_pgt kernel high mapping*/ init_level4_pgt[511] = early_level4_pgt[511]; - kasan_map_early_shadow(init_level4_pgt); - x86_64_start_reservations(real_mode_data); } --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -516,38 +516,9 @@ ENTRY(phys_base) /* This must match the first entry in level2_kernel_pgt */ .quad 0x0000000000000000 -#ifdef CONFIG_KASAN -#define FILL(VAL, COUNT) \ - .rept (COUNT) ; \ - .quad (VAL) ; \ - .endr - -NEXT_PAGE(kasan_zero_pte) - FILL(kasan_zero_page - __START_KERNEL_map + _KERNPG_TABLE, 512) -NEXT_PAGE(kasan_zero_pmd) - FILL(kasan_zero_pte - __START_KERNEL_map + _KERNPG_TABLE, 512) -NEXT_PAGE(kasan_zero_pud) - FILL(kasan_zero_pmd - __START_KERNEL_map + _KERNPG_TABLE, 512) - -#undef FILL -#endif - - #include "../../x86/xen/xen-head.S" __PAGE_ALIGNED_BSS NEXT_PAGE(empty_zero_page) .skip PAGE_SIZE -#ifdef CONFIG_KASAN -/* - * This page used as early shadow. We don't use empty_zero_page - * at early stages, stack instrumentation could write some garbage - * to this page. - * Latter we reuse it as zero shadow for large ranges of memory - * that allowed to access, but not instrumented by kasan - * (vmalloc/vmemmap ...). - */ -NEXT_PAGE(kasan_zero_page) - .skip PAGE_SIZE -#endif --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -11,7 +11,19 @@ extern pgd_t early_level4_pgt[PTRS_PER_PGD]; extern struct range pfn_mapped[E820_X_MAX]; -extern unsigned char kasan_zero_page[PAGE_SIZE]; +static pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; +static pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; +static pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; + +/* + * This page used as early shadow. We don't use empty_zero_page + * at early stages, stack instrumentation could write some garbage + * to this page. + * Latter we reuse it as zero shadow for large ranges of memory + * that allowed to access, but not instrumented by kasan + * (vmalloc/vmemmap ...). + */ +static unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; static int __init map_range(struct range *range) { @@ -36,7 +48,7 @@ static void __init clear_pgds(unsigned l pgd_clear(pgd_offset_k(start)); } -void __init kasan_map_early_shadow(pgd_t *pgd) +static void __init kasan_map_early_shadow(pgd_t *pgd) { int i; unsigned long start = KASAN_SHADOW_START; @@ -166,6 +178,26 @@ static struct notifier_block kasan_die_n }; #endif +void __init kasan_early_init(void) +{ + int i; + pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL; + pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE; + pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE; + + for (i = 0; i < PTRS_PER_PTE; i++) + kasan_zero_pte[i] = __pte(pte_val); + + for (i = 0; i < PTRS_PER_PMD; i++) + kasan_zero_pmd[i] = __pmd(pmd_val); + + for (i = 0; i < PTRS_PER_PUD; i++) + kasan_zero_pud[i] = __pud(pud_val); + + kasan_map_early_shadow(early_level4_pgt); + kasan_map_early_shadow(init_level4_pgt); +} + void __init kasan_init(void) { int i; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
