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authorAndrey Ryabinin <ryabinin.a.a@gmail.com>2015-10-12 18:52:58 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2015-10-12 17:46:36 +0100
commit39d114ddc68223022c12ae3a1573912bc4b585e5 (patch)
tree738d0566a0b66a8fec44b04fa1480f258e00a248 /arch/arm64/Makefile
parentfd2203dd3556f6553231fa026060793e67a25ce6 (diff)
downloadlinux-39d114ddc68223022c12ae3a1573912bc4b585e5.tar.gz
arm64: add KASAN support
This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/Makefile')
-rw-r--r--arch/arm64/Makefile7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index f9914d7c1bb0..f41c6761ec36 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -55,6 +55,13 @@ else
TEXT_OFFSET := 0x00080000
endif
+# KASAN_SHADOW_OFFSET = VA_START + (1 << (VA_BITS - 3)) - (1 << 61)
+# in 32-bit arithmetic
+KASAN_SHADOW_OFFSET := $(shell printf "0x%08x00000000\n" $$(( \
+ (0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 32))) \
+ + (1 << ($(CONFIG_ARM64_VA_BITS) - 32 - 3)) \
+ - (1 << (64 - 32 - 3)) )) )
+
export TEXT_OFFSET GZFLAGS
core-y += arch/arm64/kernel/ arch/arm64/mm/