kasan: group vmalloc code

This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.

Group all vmalloc-related function declarations in include/linux/kasan.h,
and their implementations in mm/kasan/common.c.

No functional changes.

Link: https://lkml.kernel.org/r/80a6fdd29b039962843bd6cf22ce2643a7c8904e.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <[email protected]>
Signed-off-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Marco Elver <[email protected]>
Reviewed-by: Alexander Potapenko <[email protected]>
Tested-by: Vincenzo Frascino <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Branislav Rankov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Evgenii Stepanov <[email protected]>
Cc: Kevin Brodsky <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

include/linux/kasan.h

@@ -75,19 +75,6 @@ struct kasan_cache {
 	int free_meta_offset;
 };
 
-/*
- * These functions provide a special case to support backing module
- * allocations with real shadow memory. With KASAN vmalloc, the special
- * case is unnecessary, as the work is handled in the generic case.
- */
-#ifndef CONFIG_KASAN_VMALLOC
-int kasan_module_alloc(void *addr, size_t size);
-void kasan_free_shadow(const struct vm_struct *vm);
-#else
-static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
-static inline void kasan_free_shadow(const struct vm_struct *vm) {}
-#endif
-
 int kasan_add_zero_shadow(void *start, unsigned long size);
 void kasan_remove_zero_shadow(void *start, unsigned long size);
 
@@ -156,9 +143,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
 	return false;
 }
 
-static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
-static inline void kasan_free_shadow(const struct vm_struct *vm) {}
-
 static inline int kasan_add_zero_shadow(void *start, unsigned long size)
 {
 	return 0;
@@ -211,13 +195,16 @@ static inline void *kasan_reset_tag(const void *addr)
 #endif /* CONFIG_KASAN_SW_TAGS */
 
 #ifdef CONFIG_KASAN_VMALLOC
+
 int kasan_populate_vmalloc(unsigned long addr, unsigned long size);
 void kasan_poison_vmalloc(const void *start, unsigned long size);
 void kasan_unpoison_vmalloc(const void *start, unsigned long size);
 void kasan_release_vmalloc(unsigned long start, unsigned long end,
 			   unsigned long free_region_start,
 			   unsigned long free_region_end);
-#else
+
+#else /* CONFIG_KASAN_VMALLOC */
+
 static inline int kasan_populate_vmalloc(unsigned long start,
 					unsigned long size)
 {
@@ -232,7 +219,25 @@ static inline void kasan_release_vmalloc(unsigned long start,
 					 unsigned long end,
 					 unsigned long free_region_start,
 					 unsigned long free_region_end) {}
-#endif
+
+#endif /* CONFIG_KASAN_VMALLOC */
+
+#if defined(CONFIG_KASAN) && !defined(CONFIG_KASAN_VMALLOC)
+
+/*
+ * These functions provide a special case to support backing module
+ * allocations with real shadow memory. With KASAN vmalloc, the special
+ * case is unnecessary, as the work is handled in the generic case.
+ */
+int kasan_module_alloc(void *addr, size_t size);
+void kasan_free_shadow(const struct vm_struct *vm);
+
+#else /* CONFIG_KASAN && !CONFIG_KASAN_VMALLOC */
+
+static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
+static inline void kasan_free_shadow(const struct vm_struct *vm) {}
+
+#endif /* CONFIG_KASAN && !CONFIG_KASAN_VMALLOC */
 
 #ifdef CONFIG_KASAN_INLINE
 void kasan_non_canonical_hook(unsigned long addr);

mm/kasan/common.c

@@ -536,44 +536,6 @@ void kasan_kfree_large(void *ptr, unsigned long ip)
 	/* The object will be poisoned by page_alloc. */
 }
 
-#ifndef CONFIG_KASAN_VMALLOC
-int kasan_module_alloc(void *addr, size_t size)
-{
-	void *ret;
-	size_t scaled_size;
-	size_t shadow_size;
-	unsigned long shadow_start;
-
-	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
-	scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
-	shadow_size = round_up(scaled_size, PAGE_SIZE);
-
-	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
-		return -EINVAL;
-
-	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
-			shadow_start + shadow_size,
-			GFP_KERNEL,
-			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
-			__builtin_return_address(0));
-
-	if (ret) {
-		__memset(ret, KASAN_SHADOW_INIT, shadow_size);
-		find_vm_area(addr)->flags |= VM_KASAN;
-		kmemleak_ignore(ret);
-		return 0;
-	}
-
-	return -ENOMEM;
-}
-
-void kasan_free_shadow(const struct vm_struct *vm)
-{
-	if (vm->flags & VM_KASAN)
-		vfree(kasan_mem_to_shadow(vm->addr));
-}
-#endif
-
 #ifdef CONFIG_MEMORY_HOTPLUG
 static bool shadow_mapped(unsigned long addr)
 {
@@ -685,6 +647,7 @@ core_initcall(kasan_memhotplug_init);
 #endif
 
 #ifdef CONFIG_KASAN_VMALLOC
+
 static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
 				      void *unused)
 {
@@ -923,4 +886,43 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
 				       (unsigned long)shadow_end);
 	}
 }
+
+#else /* CONFIG_KASAN_VMALLOC */
+
+int kasan_module_alloc(void *addr, size_t size)
+{
+	void *ret;
+	size_t scaled_size;
+	size_t shadow_size;
+	unsigned long shadow_start;
+
+	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
+	scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
+	shadow_size = round_up(scaled_size, PAGE_SIZE);
+
+	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
+		return -EINVAL;
+
+	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
+			shadow_start + shadow_size,
+			GFP_KERNEL,
+			PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
+			__builtin_return_address(0));
+
+	if (ret) {
+		__memset(ret, KASAN_SHADOW_INIT, shadow_size);
+		find_vm_area(addr)->flags |= VM_KASAN;
+		kmemleak_ignore(ret);
+		return 0;
+	}
+
+	return -ENOMEM;
+}
+
+void kasan_free_shadow(const struct vm_struct *vm)
+{
+	if (vm->flags & VM_KASAN)
+		vfree(kasan_mem_to_shadow(vm->addr));
+}
+
 #endif