kasan: rename kasan_zero_page to kasan_early_shadow_page

With tag based KASAN mode the early shadow value is 0xff and not 0x00, so
this patch renames kasan_zero_(page|pte|pmd|pud|p4d) to
kasan_early_shadow_(page|pte|pmd|pud|p4d) to avoid confusion.

Link: http://lkml.kernel.org/r/3fed313280ebf4f88645f5b89ccbc066d320e177.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
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>

Author: xairy

arch/arm64/mm/kasan_init.c

@@ -47,8 +47,9 @@ static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node,
 				      bool early)
 {
 	if (pmd_none(READ_ONCE(*pmdp))) {
-		phys_addr_t pte_phys = early ? __pa_symbol(kasan_zero_pte)
-					     : kasan_alloc_zeroed_page(node);
+		phys_addr_t pte_phys = early ?
+				__pa_symbol(kasan_early_shadow_pte)
+					: kasan_alloc_zeroed_page(node);
 		__pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
 	}
 
@@ -60,8 +61,9 @@ static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node,
 				      bool early)
 {
 	if (pud_none(READ_ONCE(*pudp))) {
-		phys_addr_t pmd_phys = early ? __pa_symbol(kasan_zero_pmd)
-					     : kasan_alloc_zeroed_page(node);
+		phys_addr_t pmd_phys = early ?
+				__pa_symbol(kasan_early_shadow_pmd)
+					: kasan_alloc_zeroed_page(node);
 		__pud_populate(pudp, pmd_phys, PMD_TYPE_TABLE);
 	}
 
@@ -72,8 +74,9 @@ static pud_t *__init kasan_pud_offset(pgd_t *pgdp, unsigned long addr, int node,
 				      bool early)
 {
 	if (pgd_none(READ_ONCE(*pgdp))) {
-		phys_addr_t pud_phys = early ? __pa_symbol(kasan_zero_pud)
-					     : kasan_alloc_zeroed_page(node);
+		phys_addr_t pud_phys = early ?
+				__pa_symbol(kasan_early_shadow_pud)
+					: kasan_alloc_zeroed_page(node);
 		__pgd_populate(pgdp, pud_phys, PMD_TYPE_TABLE);
 	}
 
@@ -87,8 +90,9 @@ static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
 	pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);
 
 	do {
-		phys_addr_t page_phys = early ? __pa_symbol(kasan_zero_page)
-					      : kasan_alloc_zeroed_page(node);
+		phys_addr_t page_phys = early ?
+				__pa_symbol(kasan_early_shadow_page)
+					: kasan_alloc_zeroed_page(node);
 		next = addr + PAGE_SIZE;
 		set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
 	} while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
@@ -205,14 +209,14 @@ void __init kasan_init(void)
 	kasan_map_populate(kimg_shadow_start, kimg_shadow_end,
 			   early_pfn_to_nid(virt_to_pfn(lm_alias(_text))));
 
-	kasan_populate_zero_shadow((void *)KASAN_SHADOW_START,
-				   (void *)mod_shadow_start);
-	kasan_populate_zero_shadow((void *)kimg_shadow_end,
-				   kasan_mem_to_shadow((void *)PAGE_OFFSET));
+	kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
+				    (void *)mod_shadow_start);
+	kasan_populate_early_shadow((void *)kimg_shadow_end,
+				    kasan_mem_to_shadow((void *)PAGE_OFFSET));
 
 	if (kimg_shadow_start > mod_shadow_end)
-		kasan_populate_zero_shadow((void *)mod_shadow_end,
-					   (void *)kimg_shadow_start);
+		kasan_populate_early_shadow((void *)mod_shadow_end,
+					    (void *)kimg_shadow_start);
 
 	for_each_memblock(memory, reg) {
 		void *start = (void *)__phys_to_virt(reg->base);
@@ -227,14 +231,15 @@ void __init kasan_init(void)
 	}
 
 	/*
-	 * KAsan may reuse the contents of kasan_zero_pte directly, so we
-	 * should make sure that it maps the zero page read-only.
+	 * KAsan may reuse the contents of kasan_early_shadow_pte directly,
+	 * so we should make sure that it maps the zero page read-only.
 	 */
 	for (i = 0; i < PTRS_PER_PTE; i++)
-		set_pte(&kasan_zero_pte[i],
-			pfn_pte(sym_to_pfn(kasan_zero_page), PAGE_KERNEL_RO));
+		set_pte(&kasan_early_shadow_pte[i],
+			pfn_pte(sym_to_pfn(kasan_early_shadow_page),
+				PAGE_KERNEL_RO));
 
-	memset(kasan_zero_page, 0, PAGE_SIZE);
+	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 	cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 
 	/* At this point kasan is fully initialized. Enable error messages */

arch/s390/mm/dump_pagetables.c

@@ -111,11 +111,12 @@ static void note_page(struct seq_file *m, struct pg_state *st,
 }
 
 #ifdef CONFIG_KASAN
-static void note_kasan_zero_page(struct seq_file *m, struct pg_state *st)
+static void note_kasan_early_shadow_page(struct seq_file *m,
+						struct pg_state *st)
 {
 	unsigned int prot;
 
-	prot = pte_val(*kasan_zero_pte) &
+	prot = pte_val(*kasan_early_shadow_pte) &
 		(_PAGE_PROTECT | _PAGE_INVALID | _PAGE_NOEXEC);
 	note_page(m, st, prot, 4);
 }
@@ -154,8 +155,8 @@ static void walk_pmd_level(struct seq_file *m, struct pg_state *st,
 	int i;
 
 #ifdef CONFIG_KASAN
-	if ((pud_val(*pud) & PAGE_MASK) == __pa(kasan_zero_pmd)) {
-		note_kasan_zero_page(m, st);
+	if ((pud_val(*pud) & PAGE_MASK) == __pa(kasan_early_shadow_pmd)) {
+		note_kasan_early_shadow_page(m, st);
 		return;
 	}
 #endif
@@ -185,8 +186,8 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st,
 	int i;
 
 #ifdef CONFIG_KASAN
-	if ((p4d_val(*p4d) & PAGE_MASK) == __pa(kasan_zero_pud)) {
-		note_kasan_zero_page(m, st);
+	if ((p4d_val(*p4d) & PAGE_MASK) == __pa(kasan_early_shadow_pud)) {
+		note_kasan_early_shadow_page(m, st);
 		return;
 	}
 #endif
@@ -215,8 +216,8 @@ static void walk_p4d_level(struct seq_file *m, struct pg_state *st,
 	int i;
 
 #ifdef CONFIG_KASAN
-	if ((pgd_val(*pgd) & PAGE_MASK) == __pa(kasan_zero_p4d)) {
-		note_kasan_zero_page(m, st);
+	if ((pgd_val(*pgd) & PAGE_MASK) == __pa(kasan_early_shadow_p4d)) {
+		note_kasan_early_shadow_page(m, st);
 		return;
 	}
 #endif

arch/s390/mm/kasan_init.c

@@ -107,7 +107,8 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
 			if (mode == POPULATE_ZERO_SHADOW &&
 			    IS_ALIGNED(address, PGDIR_SIZE) &&
 			    end - address >= PGDIR_SIZE) {
-				pgd_populate(&init_mm, pg_dir, kasan_zero_p4d);
+				pgd_populate(&init_mm, pg_dir,
+						kasan_early_shadow_p4d);
 				address = (address + PGDIR_SIZE) & PGDIR_MASK;
 				continue;
 			}
@@ -120,7 +121,8 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
 			if (mode == POPULATE_ZERO_SHADOW &&
 			    IS_ALIGNED(address, P4D_SIZE) &&
 			    end - address >= P4D_SIZE) {
-				p4d_populate(&init_mm, p4_dir, kasan_zero_pud);
+				p4d_populate(&init_mm, p4_dir,
+						kasan_early_shadow_pud);
 				address = (address + P4D_SIZE) & P4D_MASK;
 				continue;
 			}
@@ -133,7 +135,8 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
 			if (mode == POPULATE_ZERO_SHADOW &&
 			    IS_ALIGNED(address, PUD_SIZE) &&
 			    end - address >= PUD_SIZE) {
-				pud_populate(&init_mm, pu_dir, kasan_zero_pmd);
+				pud_populate(&init_mm, pu_dir,
+						kasan_early_shadow_pmd);
 				address = (address + PUD_SIZE) & PUD_MASK;
 				continue;
 			}
@@ -146,7 +149,8 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
 			if (mode == POPULATE_ZERO_SHADOW &&
 			    IS_ALIGNED(address, PMD_SIZE) &&
 			    end - address >= PMD_SIZE) {
-				pmd_populate(&init_mm, pm_dir, kasan_zero_pte);
+				pmd_populate(&init_mm, pm_dir,
+						kasan_early_shadow_pte);
 				address = (address + PMD_SIZE) & PMD_MASK;
 				continue;
 			}
@@ -188,7 +192,7 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
 				pte_val(*pt_dir) = __pa(page) | pgt_prot;
 				break;
 			case POPULATE_ZERO_SHADOW:
-				page = kasan_zero_page;
+				page = kasan_early_shadow_page;
 				pte_val(*pt_dir) = __pa(page) | pgt_prot_zero;
 				break;
 			}
@@ -256,14 +260,14 @@ void __init kasan_early_init(void)
 	unsigned long vmax;
 	unsigned long pgt_prot = pgprot_val(PAGE_KERNEL_RO);
 	pte_t pte_z;
-	pmd_t pmd_z = __pmd(__pa(kasan_zero_pte) | _SEGMENT_ENTRY);
-	pud_t pud_z = __pud(__pa(kasan_zero_pmd) | _REGION3_ENTRY);
-	p4d_t p4d_z = __p4d(__pa(kasan_zero_pud) | _REGION2_ENTRY);
+	pmd_t pmd_z = __pmd(__pa(kasan_early_shadow_pte) | _SEGMENT_ENTRY);
+	pud_t pud_z = __pud(__pa(kasan_early_shadow_pmd) | _REGION3_ENTRY);
+	p4d_t p4d_z = __p4d(__pa(kasan_early_shadow_pud) | _REGION2_ENTRY);
 
 	kasan_early_detect_facilities();
 	if (!has_nx)
 		pgt_prot &= ~_PAGE_NOEXEC;
-	pte_z = __pte(__pa(kasan_zero_page) | pgt_prot);
+	pte_z = __pte(__pa(kasan_early_shadow_page) | pgt_prot);
 
 	memsize = get_mem_detect_end();
 	if (!memsize)
@@ -292,10 +296,13 @@ void __init kasan_early_init(void)
 	}
 
 	/* init kasan zero shadow */
-	crst_table_init((unsigned long *)kasan_zero_p4d, p4d_val(p4d_z));
-	crst_table_init((unsigned long *)kasan_zero_pud, pud_val(pud_z));
-	crst_table_init((unsigned long *)kasan_zero_pmd, pmd_val(pmd_z));
-	memset64((u64 *)kasan_zero_pte, pte_val(pte_z), PTRS_PER_PTE);
+	crst_table_init((unsigned long *)kasan_early_shadow_p4d,
+				p4d_val(p4d_z));
+	crst_table_init((unsigned long *)kasan_early_shadow_pud,
+				pud_val(pud_z));
+	crst_table_init((unsigned long *)kasan_early_shadow_pmd,
+				pmd_val(pmd_z));
+	memset64((u64 *)kasan_early_shadow_pte, pte_val(pte_z), PTRS_PER_PTE);
 
 	shadow_alloc_size = memsize >> KASAN_SHADOW_SCALE_SHIFT;
 	pgalloc_low = round_up((unsigned long)_end, _SEGMENT_SIZE);

arch/x86/mm/dump_pagetables.c

@@ -377,18 +377,19 @@ static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr,
 
 /*
  * This is an optimization for KASAN=y case. Since all kasan page tables
- * eventually point to the kasan_zero_page we could call note_page()
+ * eventually point to the kasan_early_shadow_page we could call note_page()
  * right away without walking through lower level page tables. This saves
  * us dozens of seconds (minutes for 5-level config) while checking for
  * W+X mapping or reading kernel_page_tables debugfs file.
  */
 static inline bool kasan_page_table(struct seq_file *m, struct pg_state *st,
 				void *pt)
 {
-	if (__pa(pt) == __pa(kasan_zero_pmd) ||
-	    (pgtable_l5_enabled() && __pa(pt) == __pa(kasan_zero_p4d)) ||
-	    __pa(pt) == __pa(kasan_zero_pud)) {
-		pgprotval_t prot = pte_flags(kasan_zero_pte[0]);
+	if (__pa(pt) == __pa(kasan_early_shadow_pmd) ||
+	    (pgtable_l5_enabled() &&
+			__pa(pt) == __pa(kasan_early_shadow_p4d)) ||
+	    __pa(pt) == __pa(kasan_early_shadow_pud)) {
+		pgprotval_t prot = pte_flags(kasan_early_shadow_pte[0]);
 		note_page(m, st, __pgprot(prot), 0, 5);
 		return true;
 	}

arch/x86/mm/kasan_init_64.c

@@ -211,7 +211,8 @@ static void __init kasan_early_p4d_populate(pgd_t *pgd,
 	unsigned long next;
 
 	if (pgd_none(*pgd)) {
-		pgd_entry = __pgd(_KERNPG_TABLE | __pa_nodebug(kasan_zero_p4d));
+		pgd_entry = __pgd(_KERNPG_TABLE |
+					__pa_nodebug(kasan_early_shadow_p4d));
 		set_pgd(pgd, pgd_entry);
 	}
 
@@ -222,7 +223,8 @@ static void __init kasan_early_p4d_populate(pgd_t *pgd,
 		if (!p4d_none(*p4d))
 			continue;
 
-		p4d_entry = __p4d(_KERNPG_TABLE | __pa_nodebug(kasan_zero_pud));
+		p4d_entry = __p4d(_KERNPG_TABLE |
+					__pa_nodebug(kasan_early_shadow_pud));
 		set_p4d(p4d, p4d_entry);
 	} while (p4d++, addr = next, addr != end && p4d_none(*p4d));
 }
@@ -261,10 +263,11 @@ static struct notifier_block kasan_die_notifier = {
 void __init kasan_early_init(void)
 {
 	int i;
-	pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL | _PAGE_ENC;
-	pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE;
-	pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE;
-	p4dval_t p4d_val = __pa_nodebug(kasan_zero_pud) | _KERNPG_TABLE;
+	pteval_t pte_val = __pa_nodebug(kasan_early_shadow_page) |
+				__PAGE_KERNEL | _PAGE_ENC;
+	pmdval_t pmd_val = __pa_nodebug(kasan_early_shadow_pte) | _KERNPG_TABLE;
+	pudval_t pud_val = __pa_nodebug(kasan_early_shadow_pmd) | _KERNPG_TABLE;
+	p4dval_t p4d_val = __pa_nodebug(kasan_early_shadow_pud) | _KERNPG_TABLE;
 
 	/* Mask out unsupported __PAGE_KERNEL bits: */
 	pte_val &= __default_kernel_pte_mask;
@@ -273,16 +276,16 @@ void __init kasan_early_init(void)
 	p4d_val &= __default_kernel_pte_mask;
 
 	for (i = 0; i < PTRS_PER_PTE; i++)
-		kasan_zero_pte[i] = __pte(pte_val);
+		kasan_early_shadow_pte[i] = __pte(pte_val);
 
 	for (i = 0; i < PTRS_PER_PMD; i++)
-		kasan_zero_pmd[i] = __pmd(pmd_val);
+		kasan_early_shadow_pmd[i] = __pmd(pmd_val);
 
 	for (i = 0; i < PTRS_PER_PUD; i++)
-		kasan_zero_pud[i] = __pud(pud_val);
+		kasan_early_shadow_pud[i] = __pud(pud_val);
 
 	for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++)
-		kasan_zero_p4d[i] = __p4d(p4d_val);
+		kasan_early_shadow_p4d[i] = __p4d(p4d_val);
 
 	kasan_map_early_shadow(early_top_pgt);
 	kasan_map_early_shadow(init_top_pgt);
@@ -326,7 +329,7 @@ void __init kasan_init(void)
 
 	clear_pgds(KASAN_SHADOW_START & PGDIR_MASK, KASAN_SHADOW_END);
 
-	kasan_populate_zero_shadow((void *)(KASAN_SHADOW_START & PGDIR_MASK),
+	kasan_populate_early_shadow((void *)(KASAN_SHADOW_START & PGDIR_MASK),
 			kasan_mem_to_shadow((void *)PAGE_OFFSET));
 
 	for (i = 0; i < E820_MAX_ENTRIES; i++) {
@@ -338,50 +341,50 @@ void __init kasan_init(void)
 
 	shadow_cpu_entry_begin = (void *)CPU_ENTRY_AREA_BASE;
 	shadow_cpu_entry_begin = kasan_mem_to_shadow(shadow_cpu_entry_begin);
-	shadow_cpu_entry_begin = (void *)round_down((unsigned long)shadow_cpu_entry_begin,
-						PAGE_SIZE);
+	shadow_cpu_entry_begin = (void *)round_down(
+			(unsigned long)shadow_cpu_entry_begin, PAGE_SIZE);
 
 	shadow_cpu_entry_end = (void *)(CPU_ENTRY_AREA_BASE +
 					CPU_ENTRY_AREA_MAP_SIZE);
 	shadow_cpu_entry_end = kasan_mem_to_shadow(shadow_cpu_entry_end);
-	shadow_cpu_entry_end = (void *)round_up((unsigned long)shadow_cpu_entry_end,
-					PAGE_SIZE);
+	shadow_cpu_entry_end = (void *)round_up(
+			(unsigned long)shadow_cpu_entry_end, PAGE_SIZE);
 
-	kasan_populate_zero_shadow(
+	kasan_populate_early_shadow(
 		kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
 		shadow_cpu_entry_begin);
 
 	kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
 			      (unsigned long)shadow_cpu_entry_end, 0);
 
-	kasan_populate_zero_shadow(shadow_cpu_entry_end,
-				kasan_mem_to_shadow((void *)__START_KERNEL_map));
+	kasan_populate_early_shadow(shadow_cpu_entry_end,
+			kasan_mem_to_shadow((void *)__START_KERNEL_map));
 
 	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);
+	kasan_populate_early_shadow(kasan_mem_to_shadow((void *)MODULES_END),
+					(void *)KASAN_SHADOW_END);
 
 	load_cr3(init_top_pgt);
 	__flush_tlb_all();
 
 	/*
-	 * kasan_zero_page has been used as early shadow memory, thus it may
-	 * contain some garbage. Now we can clear and write protect it, since
-	 * after the TLB flush no one should write to it.
+	 * kasan_early_shadow_page has been used as early shadow memory, thus
+	 * it may contain some garbage. Now we can clear and write protect it,
+	 * since after the TLB flush no one should write to it.
 	 */
-	memset(kasan_zero_page, 0, PAGE_SIZE);
+	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 	for (i = 0; i < PTRS_PER_PTE; i++) {
 		pte_t pte;
 		pgprot_t prot;
 
 		prot = __pgprot(__PAGE_KERNEL_RO | _PAGE_ENC);
 		pgprot_val(prot) &= __default_kernel_pte_mask;
 
-		pte = __pte(__pa(kasan_zero_page) | pgprot_val(prot));
-		set_pte(&kasan_zero_pte[i], pte);
+		pte = __pte(__pa(kasan_early_shadow_page) | pgprot_val(prot));
+		set_pte(&kasan_early_shadow_pte[i], pte);
 	}
 	/* Flush TLBs again to be sure that write protection applied. */
 	__flush_tlb_all();