diff options
| -rw-r--r-- | Documentation/x86/x86_64/mm.txt | 2 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/Makefile | 3 | ||||
| -rw-r--r-- | arch/x86/mm/kasan_init_64.c | 101 |
4 files changed, 83 insertions, 24 deletions
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index b0798e281aa6..3448e675b462 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -34,7 +34,7 @@ ff92000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space ffd2000000000000 - ffd3ffffffffffff (=49 bits) hole ffd4000000000000 - ffd5ffffffffffff (=49 bits) virtual memory map (512TB) ... unused hole ... -ffd8000000000000 - fff7ffffffffffff (=53 bits) kasan shadow memory (8PB) +ffdf000000000000 - fffffc0000000000 (=53 bits) kasan shadow memory (8PB) ... unused hole ... ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks ... unused hole ... diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 971feac13506..32779beb56e2 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -302,7 +302,6 @@ config ARCH_SUPPORTS_DEBUG_PAGEALLOC config KASAN_SHADOW_OFFSET hex depends on KASAN - default 0xdff8000000000000 if X86_5LEVEL default 0xdffffc0000000000 config HAVE_INTEL_TXT diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index fd0a7895b63f..a97a6b611531 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -24,7 +24,8 @@ endif KASAN_SANITIZE_head$(BITS).o := n KASAN_SANITIZE_dumpstack.o := n KASAN_SANITIZE_dumpstack_$(BITS).o := n -KASAN_SANITIZE_stacktrace.o := n +KASAN_SANITIZE_stacktrace.o := n +KASAN_SANITIZE_paravirt.o := n OBJECT_FILES_NON_STANDARD_head_$(BITS).o := y OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index bc84b73684b7..fe5760db7b19 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -15,6 +15,8 @@ extern struct range pfn_mapped[E820_MAX_ENTRIES]; +static p4d_t tmp_p4d_table[PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE); + static int __init map_range(struct range *range) { unsigned long start; @@ -30,8 +32,10 @@ static void __init clear_pgds(unsigned long start, unsigned long end) { pgd_t *pgd; + /* See comment in kasan_init() */ + unsigned long pgd_end = end & PGDIR_MASK; - for (; start < end; start += PGDIR_SIZE) { + for (; start < pgd_end; start += PGDIR_SIZE) { pgd = pgd_offset_k(start); /* * With folded p4d, pgd_clear() is nop, use p4d_clear() @@ -42,29 +46,61 @@ static void __init clear_pgds(unsigned long start, else pgd_clear(pgd); } + + pgd = pgd_offset_k(start); + for (; start < end; start += P4D_SIZE) + p4d_clear(p4d_offset(pgd, start)); +} + +static inline p4d_t *early_p4d_offset(pgd_t *pgd, unsigned long addr) +{ + unsigned long p4d; + + if (!IS_ENABLED(CONFIG_X86_5LEVEL)) + return (p4d_t *)pgd; + + p4d = __pa_nodebug(pgd_val(*pgd)) & PTE_PFN_MASK; + p4d += __START_KERNEL_map - phys_base; + return (p4d_t *)p4d + p4d_index(addr); +} + +static void __init kasan_early_p4d_populate(pgd_t *pgd, + unsigned long addr, + unsigned long end) +{ + pgd_t pgd_entry; + p4d_t *p4d, p4d_entry; + unsigned long next; + + if (pgd_none(*pgd)) { + pgd_entry = __pgd(_KERNPG_TABLE | __pa_nodebug(kasan_zero_p4d)); + set_pgd(pgd, pgd_entry); + } + + p4d = early_p4d_offset(pgd, addr); + do { + next = p4d_addr_end(addr, end); + + if (!p4d_none(*p4d)) + continue; + + p4d_entry = __p4d(_KERNPG_TABLE | __pa_nodebug(kasan_zero_pud)); + set_p4d(p4d, p4d_entry); + } while (p4d++, addr = next, addr != end && p4d_none(*p4d)); } static void __init kasan_map_early_shadow(pgd_t *pgd) { - int i; - unsigned long start = KASAN_SHADOW_START; + /* See comment in kasan_init() */ + unsigned long addr = KASAN_SHADOW_START & PGDIR_MASK; unsigned long end = KASAN_SHADOW_END; + unsigned long next; - for (i = pgd_index(start); start < end; i++) { - switch (CONFIG_PGTABLE_LEVELS) { - case 4: - pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud) | - _KERNPG_TABLE); - break; - case 5: - pgd[i] = __pgd(__pa_nodebug(kasan_zero_p4d) | - _KERNPG_TABLE); - break; - default: - BUILD_BUG(); - } - start += PGDIR_SIZE; - } + pgd += pgd_index(addr); + do { + next = pgd_addr_end(addr, end); + kasan_early_p4d_populate(pgd, addr, next); + } while (pgd++, addr = next, addr != end); } #ifdef CONFIG_KASAN_INLINE @@ -101,7 +137,7 @@ void __init kasan_early_init(void) for (i = 0; i < PTRS_PER_PUD; i++) kasan_zero_pud[i] = __pud(pud_val); - for (i = 0; CONFIG_PGTABLE_LEVELS >= 5 && i < PTRS_PER_P4D; i++) + for (i = 0; IS_ENABLED(CONFIG_X86_5LEVEL) && i < PTRS_PER_P4D; i++) kasan_zero_p4d[i] = __p4d(p4d_val); kasan_map_early_shadow(early_top_pgt); @@ -117,12 +153,35 @@ void __init kasan_init(void) #endif memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt)); + + /* + * We use the same shadow offset for 4- and 5-level paging to + * facilitate boot-time switching between paging modes. + * As result in 5-level paging mode KASAN_SHADOW_START and + * KASAN_SHADOW_END are not aligned to PGD boundary. + * + * KASAN_SHADOW_START doesn't share PGD with anything else. + * We claim whole PGD entry to make things easier. + * + * KASAN_SHADOW_END lands in the last PGD entry and it collides with + * bunch of things like kernel code, modules, EFI mapping, etc. + * We need to take extra steps to not overwrite them. + */ + if (IS_ENABLED(CONFIG_X86_5LEVEL)) { + void *ptr; + + ptr = (void *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END)); + memcpy(tmp_p4d_table, (void *)ptr, sizeof(tmp_p4d_table)); + set_pgd(&early_top_pgt[pgd_index(KASAN_SHADOW_END)], + __pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE)); + } + load_cr3(early_top_pgt); __flush_tlb_all(); - clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); + clear_pgds(KASAN_SHADOW_START & PGDIR_MASK, KASAN_SHADOW_END); - kasan_populate_zero_shadow((void *)KASAN_SHADOW_START, + kasan_populate_zero_shadow((void *)(KASAN_SHADOW_START & PGDIR_MASK), kasan_mem_to_shadow((void *)PAGE_OFFSET)); for (i = 0; i < E820_MAX_ENTRIES; i++) { |