kasan: Add __HAVE_ARCH_SHADOW_MAP to support arch specific mapping

MIPS, LoongArch and some other architectures have many holes between
different segments and the valid address space (256T available) is
insufficient to map all these segments to kasan shadow memory with the
common formula provided by kasan core. So we need architecture specific
mapping formulas to ensure different segments are mapped individually,
and only limited space lengths of those specific segments are mapped to
shadow.

Therefore, when the incoming address is converted to a shadow, we need
to add a condition to determine whether it is valid.

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 819b6bc8ac0886d8d671a117ac9d9c694baebe95..3df5499f79369df25448c3069f00888d0cbb31f2 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -54,11 +54,13 @@ extern p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D];
 int kasan_populate_early_shadow(const void *shadow_start,
                                const void *shadow_end);
 
+#ifndef __HAVE_ARCH_SHADOW_MAP
 static inline void *kasan_mem_to_shadow(const void *addr)
 {
        return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT)
                + KASAN_SHADOW_OFFSET;
 }
+#endif
 
 int kasan_add_zero_shadow(void *start, unsigned long size);
 void kasan_remove_zero_shadow(void *start, unsigned long size);

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 2e973b36fe0725339c04eda6f10446b8b28244ca..f70e3d7a602e1e816abe7357793fcb16fdfa3f91 100644 (file)
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -291,16 +291,22 @@ struct kasan_stack_ring {
 
 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 
+#ifndef __HAVE_ARCH_SHADOW_MAP
 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);
 }
+#endif
 
 static __always_inline bool addr_has_metadata(const void *addr)
 {
+#ifdef __HAVE_ARCH_SHADOW_MAP
+       return (kasan_mem_to_shadow((void *)addr) != NULL);
+#else
        return (kasan_reset_tag(addr) >=
                kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
+#endif
 }
 
 /**