[RFC PATCH V1 6/8] kasan: Allow arch to overrride kasan shadow offsets

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Some archs may want to provide kasan shadow memory as a constant
offset from the address. Such arch even though cannot use inline kasan
support, they can work with outofline kasan support.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 include/linux/kasan.h | 3 +++
 mm/kasan/kasan.h      | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 5486d777b706..e458ca64cdaf 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -15,11 +15,14 @@ struct vm_struct;
 #include <asm/kasan.h>
 #include <linux/sched.h>
 
+#ifndef kasan_mem_to_shadow
 static inline void *kasan_mem_to_shadow(const void *addr)
 {
 	return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT)
 		+ KASAN_SHADOW_OFFSET;
 }
+#define kasan_mem_to_shadow kasan_mem_to_shadow
+#endif
 
 /* Enable reporting bugs after kasan_disable_current() */
 static inline void kasan_enable_current(void)
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index deb547d5a916..c0686f2b1224 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -57,11 +57,14 @@ struct kasan_global {
 void kasan_report_error(struct kasan_access_info *info);
 void kasan_report_user_access(struct kasan_access_info *info);
 
+#ifndef kasan_shadow_to_mem
 static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
 {
 	return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
 		<< KASAN_SHADOW_SCALE_SHIFT);
 }
+#define kasan_shadow_to_mem kasan_shadow_to_mem
+#endif
 
 static inline bool kasan_report_enabled(void)
 {
-- 
2.5.0