Commit 9b04c764 authored by Qing Zhang's avatar Qing Zhang Committed by Huacai Chen
Browse files

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: default avatarAndrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: default avatarQing Zhang <zhangqing@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 6ad3df56

include/linux/kasan.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

mm/kasan/kasan.h

+6 −0
Original line number Diff line number Diff line
@@ -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

}



/**