Commit affc3f07 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

kasan: define KASAN_MEMORY_PER_SHADOW_PAGE 

Define KASAN_MEMORY_PER_SHADOW_PAGE as (KASAN_GRANULE_SIZE << PAGE_SHIFT),
which is the same as (KASAN_GRANULE_SIZE * PAGE_SIZE) for software modes
that use shadow memory, and use it across KASAN code to simplify it.

Link: https://lkml.kernel.org/r/8329391cfe14b5cffd3decf3b5c535b6ce21eef6.1606161801.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Tested-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bb359dbc

mm/kasan/init.c

+4 −6
Original line number Diff line number Diff line
@@ -441,9 +441,8 @@ void kasan_remove_zero_shadow(void *start, unsigned long size) 
	addr = (unsigned long)kasan_mem_to_shadow(start);

	end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);



	if (WARN_ON((unsigned long)start %

			(KASAN_GRANULE_SIZE * PAGE_SIZE)) ||

	    WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))

	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||

	    WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))

		return;



	for (; addr < end; addr = next) {
@@ -476,9 +475,8 @@ int kasan_add_zero_shadow(void *start, unsigned long size) 
	shadow_start = kasan_mem_to_shadow(start);

	shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);



	if (WARN_ON((unsigned long)start %

			(KASAN_GRANULE_SIZE * PAGE_SIZE)) ||

	    WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))

	if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||

	    WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))

		return -EINVAL;



	ret = kasan_populate_early_shadow(shadow_start, shadow_end);

mm/kasan/kasan.h

+2 −0
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 
#define KASAN_GRANULE_SIZE	(1UL << KASAN_SHADOW_SCALE_SHIFT)

#define KASAN_GRANULE_MASK	(KASAN_GRANULE_SIZE - 1)



#define KASAN_MEMORY_PER_SHADOW_PAGE	(KASAN_GRANULE_SIZE << PAGE_SHIFT)



#define KASAN_TAG_KERNEL	0xFF /* native kernel pointers tag */

#define KASAN_TAG_INVALID	0xFE /* inaccessible memory tag */

#define KASAN_TAG_MAX		0xFD /* maximum value for random tags */

mm/kasan/shadow.c

+7 −9
Original line number Diff line number Diff line
@@ -161,7 +161,7 @@ static int __meminit kasan_mem_notifier(struct notifier_block *nb, 
	shadow_end = shadow_start + shadow_size;



	if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||

		WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT)))

		WARN_ON(start_kaddr % KASAN_MEMORY_PER_SHADOW_PAGE))

		return NOTIFY_BAD;



	switch (action) {
@@ -432,22 +432,20 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end, 
	unsigned long region_start, region_end;

	unsigned long size;



	region_start = ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE);

	region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE);

	region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE);

	region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE);



	free_region_start = ALIGN(free_region_start,

				  PAGE_SIZE * KASAN_GRANULE_SIZE);

	free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE);



	if (start != region_start &&

	    free_region_start < region_start)

		region_start -= PAGE_SIZE * KASAN_GRANULE_SIZE;

		region_start -= KASAN_MEMORY_PER_SHADOW_PAGE;



	free_region_end = ALIGN_DOWN(free_region_end,

				     PAGE_SIZE * KASAN_GRANULE_SIZE);

	free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE);



	if (end != region_end &&

	    free_region_end > region_end)

		region_end += PAGE_SIZE * KASAN_GRANULE_SIZE;

		region_end += KASAN_MEMORY_PER_SHADOW_PAGE;



	shadow_start = kasan_mem_to_shadow((void *)region_start);

	shadow_end = kasan_mem_to_shadow((void *)region_end);