Merge branch 'mm-kasan-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86/kasan changes from Ingo Molnar:
 "These are two KASAN changes that factor out (and generalize) x86
  specific KASAN code from x86 to mm"

* 'mm-kasan-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kasan, mm: Introduce generic kasan_populate_zero_shadow()
  x86/kasan: Define KASAN_SHADOW_OFFSET per architecture

2 files changed, 8 insertions, 118 deletions

diff --git a/arch/x86/include/asm/kasan.h b/arch/x86/include/asm/kasan.h
index 74a2a8dc9908..1410b567ecde 100644
--- a/arch/x86/include/asm/kasan.h
+++ b/arch/x86/include/asm/kasan.h
@@ -1,6 +1,9 @@
 #ifndef _ASM_X86_KASAN_H
 #define _ASM_X86_KASAN_H
 
+#include <linux/const.h>
+#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
+
 /*
  * Compiler uses shadow offset assuming that addresses start
  * from 0. Kernel addresses don't start from 0, so shadow
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index e1840f3db5b5..9ce5da27b136 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -12,20 +12,6 @@
 extern pgd_t early_level4_pgt[PTRS_PER_PGD];
 extern struct range pfn_mapped[E820_X_MAX];
 
-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)
 {
 	unsigned long start;
@@ -62,106 +48,6 @@ static void __init kasan_map_early_shadow(pgd_t *pgd)
 	}
 }
 
-static int __init zero_pte_populate(pmd_t *pmd, unsigned long addr,
-				unsigned long end)
-{
-	pte_t *pte = pte_offset_kernel(pmd, addr);
-
-	while (addr + PAGE_SIZE <= end) {
-		WARN_ON(!pte_none(*pte));
-		set_pte(pte, __pte(__pa_nodebug(kasan_zero_page)
-					| __PAGE_KERNEL_RO));
-		addr += PAGE_SIZE;
-		pte = pte_offset_kernel(pmd, addr);
-	}
-	return 0;
-}
-
-static int __init zero_pmd_populate(pud_t *pud, unsigned long addr,
-				unsigned long end)
-{
-	int ret = 0;
-	pmd_t *pmd = pmd_offset(pud, addr);
-
-	while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) {
-		WARN_ON(!pmd_none(*pmd));
-		set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte)
-					| _KERNPG_TABLE));
-		addr += PMD_SIZE;
-		pmd = pmd_offset(pud, addr);
-	}
-	if (addr < end) {
-		if (pmd_none(*pmd)) {
-			void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
-			if (!p)
-				return -ENOMEM;
-			set_pmd(pmd, __pmd(__pa_nodebug(p) | _KERNPG_TABLE));
-		}
-		ret = zero_pte_populate(pmd, addr, end);
-	}
-	return ret;
-}
-
-
-static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
-				unsigned long end)
-{
-	int ret = 0;
-	pud_t *pud = pud_offset(pgd, addr);
-
-	while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) {
-		WARN_ON(!pud_none(*pud));
-		set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd)
-					| _KERNPG_TABLE));
-		addr += PUD_SIZE;
-		pud = pud_offset(pgd, addr);
-	}
-
-	if (addr < end) {
-		if (pud_none(*pud)) {
-			void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
-			if (!p)
-				return -ENOMEM;
-			set_pud(pud, __pud(__pa_nodebug(p) | _KERNPG_TABLE));
-		}
-		ret = zero_pmd_populate(pud, addr, end);
-	}
-	return ret;
-}
-
-static int __init zero_pgd_populate(unsigned long addr, unsigned long end)
-{
-	int ret = 0;
-	pgd_t *pgd = pgd_offset_k(addr);
-
-	while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) {
-		WARN_ON(!pgd_none(*pgd));
-		set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud)
-					| _KERNPG_TABLE));
-		addr += PGDIR_SIZE;
-		pgd = pgd_offset_k(addr);
-	}
-
-	if (addr < end) {
-		if (pgd_none(*pgd)) {
-			void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
-			if (!p)
-				return -ENOMEM;
-			set_pgd(pgd, __pgd(__pa_nodebug(p) | _KERNPG_TABLE));
-		}
-		ret = zero_pud_populate(pgd, addr, end);
-	}
-	return ret;
-}
-
-
-static void __init populate_zero_shadow(const void *start, const void *end)
-{
-	if (zero_pgd_populate((unsigned long)start, (unsigned long)end))
-		panic("kasan: unable to map zero shadow!");
-}
-
-
 #ifdef CONFIG_KASAN_INLINE
 static int kasan_die_handler(struct notifier_block *self,
 			     unsigned long val,
@@ -213,7 +99,7 @@ void __init kasan_init(void)
 
 	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
 
-	populate_zero_shadow((void *)KASAN_SHADOW_START,
+	kasan_populate_zero_shadow((void *)KASAN_SHADOW_START,
 			kasan_mem_to_shadow((void *)PAGE_OFFSET));
 
 	for (i = 0; i < E820_X_MAX; i++) {
@@ -223,14 +109,15 @@ void __init kasan_init(void)
 		if (map_range(&pfn_mapped[i]))
 			panic("kasan: unable to allocate shadow!");
 	}
-	populate_zero_shadow(kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
-			kasan_mem_to_shadow((void *)__START_KERNEL_map));
+	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);
 
-	populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
+	kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
 			(void *)KASAN_SHADOW_END);
 
 	memset(kasan_zero_page, 0, PAGE_SIZE);