[04/60] kasan: shadow declarations only for software modes

Commit Message

Andrew Morton Dec. 22, 2020, 8 p.m. UTC

From: Andrey Konovalov <[e-mail]>
Subject: kasan: shadow declarations only for software modes

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

Group shadow-related KASAN function declarations and only define them for
the two existing software modes.

No functional changes for software modes.

Link: https://lkml.kernel.org/r/e8[e-mail]
Signed-off-by: Andrey Konovalov <[e-mail]>
Signed-off-by: Vincenzo Frascino <[e-mail]>
Signed-off-by: Valdis Kletnieks <[e-mail]>
Reviewed-by: Marco Elver <[e-mail]>
Reviewed-by: Alexander Potapenko <[e-mail]>
Tested-by: Vincenzo Frascino <[e-mail]>
Cc: Andrey Ryabinin <[e-mail]>
Cc: Branislav Rankov <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Dmitry Vyukov <[e-mail]>
Cc: Evgenii Stepanov <[e-mail]>
Cc: Kevin Brodsky <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Will Deacon <[e-mail]>
[[e-mail]: fix build issue with asmlinkage]
  Link: https://lkml.kernel.org/r/35126.1606402815@turing-police
  Link: https://lore.kernel.org/linux-arm-kernel/24105.1606397102@turing-police/
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/kasan.h |   48 ++++++++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 16 deletions(-)

Patch

--- a/include/linux/kasan.h~kasan-shadow-declarations-only-for-software-modes
+++ a/include/linux/kasan.h
@@ -11,7 +11,7 @@  struct task_struct;
 
 #ifdef CONFIG_KASAN
 
-#include <linux/pgtable.h>
+#include <linux/linkage.h>
 #include <asm/kasan.h>
 
 /* kasan_data struct is used in KUnit tests for KASAN expected failures */
@@ -20,6 +20,20 @@  struct kunit_kasan_expectation {
 	bool report_found;
 };
 
+#endif
+
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+
+#include <linux/pgtable.h>
+
+/* Software KASAN implementations use shadow memory. */
+
+#ifdef CONFIG_KASAN_SW_TAGS
+#define KASAN_SHADOW_INIT 0xFF
+#else
+#define KASAN_SHADOW_INIT 0
+#endif
+
 extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
 extern pte_t kasan_early_shadow_pte[PTRS_PER_PTE];
 extern pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD];
@@ -35,6 +49,23 @@  static inline void *kasan_mem_to_shadow(
 		+ KASAN_SHADOW_OFFSET;
 }
 
+int kasan_add_zero_shadow(void *start, unsigned long size);
+void kasan_remove_zero_shadow(void *start, unsigned long size);
+
+#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+static inline int kasan_add_zero_shadow(void *start, unsigned long size)
+{
+	return 0;
+}
+static inline void kasan_remove_zero_shadow(void *start,
+					unsigned long size)
+{}
+
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+#ifdef CONFIG_KASAN
+
 /* Enable reporting bugs after kasan_disable_current() */
 extern void kasan_enable_current(void);
 
@@ -75,9 +106,6 @@  struct kasan_cache {
 	int free_meta_offset;
 };
 
-int kasan_add_zero_shadow(void *start, unsigned long size);
-void kasan_remove_zero_shadow(void *start, unsigned long size);
-
 size_t __ksize(const void *);
 static inline void kasan_unpoison_slab(const void *ptr)
 {
@@ -143,14 +171,6 @@  static inline bool kasan_slab_free(struc
 	return false;
 }
 
-static inline int kasan_add_zero_shadow(void *start, unsigned long size)
-{
-	return 0;
-}
-static inline void kasan_remove_zero_shadow(void *start,
-					unsigned long size)
-{}
-
 static inline void kasan_unpoison_slab(const void *ptr) { }
 static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
@@ -158,8 +178,6 @@  static inline size_t kasan_metadata_size
 
 #ifdef CONFIG_KASAN_GENERIC
 
-#define KASAN_SHADOW_INIT 0
-
 void kasan_cache_shrink(struct kmem_cache *cache);
 void kasan_cache_shutdown(struct kmem_cache *cache);
 void kasan_record_aux_stack(void *ptr);
@@ -174,8 +192,6 @@  static inline void kasan_record_aux_stac
 
 #ifdef CONFIG_KASAN_SW_TAGS
 
-#define KASAN_SHADOW_INIT 0xFF
-
 void kasan_init_tags(void);
 
 void *kasan_reset_tag(const void *addr);