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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/lib
parentfd2203dd3556f6553231fa026060793e67a25ce6 (diff)
downloadblackbird-op-linux-39d114ddc68223022c12ae3a1573912bc4b585e5.tar.gz
blackbird-op-linux-39d114ddc68223022c12ae3a1573912bc4b585e5.zip
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/lib')
-rw-r--r--arch/arm64/lib/memcpy.S3
-rw-r--r--arch/arm64/lib/memmove.S7
-rw-r--r--arch/arm64/lib/memset.S3
3 files changed, 11 insertions, 2 deletions
diff --git a/arch/arm64/lib/memcpy.S b/arch/arm64/lib/memcpy.S
index 36a6a62cf263..67613937711f 100644
--- a/arch/arm64/lib/memcpy.S
+++ b/arch/arm64/lib/memcpy.S
@@ -68,7 +68,10 @@
stp \ptr, \regB, [\regC], \val
.endm
+ .weak memcpy
+ENTRY(__memcpy)
ENTRY(memcpy)
#include "copy_template.S"
ret
ENDPIPROC(memcpy)
+ENDPROC(__memcpy)
diff --git a/arch/arm64/lib/memmove.S b/arch/arm64/lib/memmove.S
index 68e2f2035e23..a5a4459013b1 100644
--- a/arch/arm64/lib/memmove.S
+++ b/arch/arm64/lib/memmove.S
@@ -57,12 +57,14 @@ C_h .req x12
D_l .req x13
D_h .req x14
+ .weak memmove
+ENTRY(__memmove)
ENTRY(memmove)
cmp dstin, src
- b.lo memcpy
+ b.lo __memcpy
add tmp1, src, count
cmp dstin, tmp1
- b.hs memcpy /* No overlap. */
+ b.hs __memcpy /* No overlap. */
add dst, dstin, count
add src, src, count
@@ -195,3 +197,4 @@ ENTRY(memmove)
b.ne .Ltail63
ret
ENDPIPROC(memmove)
+ENDPROC(__memmove)
diff --git a/arch/arm64/lib/memset.S b/arch/arm64/lib/memset.S
index 29f405f08792..f2670a9f218c 100644
--- a/arch/arm64/lib/memset.S
+++ b/arch/arm64/lib/memset.S
@@ -54,6 +54,8 @@ dst .req x8
tmp3w .req w9
tmp3 .req x9
+ .weak memset
+ENTRY(__memset)
ENTRY(memset)
mov dst, dstin /* Preserve return value. */
and A_lw, val, #255
@@ -214,3 +216,4 @@ ENTRY(memset)
b.ne .Ltail_maybe_long
ret
ENDPIPROC(memset)
+ENDPROC(__memset)
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