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| author | Andrey Ryabinin <ryabinin.a.a@gmail.com> | 2015-10-12 18:52:58 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-10-12 19:46:36 +0300 |
| commit | 39d114ddc68223022c12ae3a1573912bc4b585e5 (patch) | |
| tree | 738d0566a0b66a8fec44b04fa1480f258e00a248 /arch/arm64/lib | |
| parent | fd2203dd3556f6553231fa026060793e67a25ce6 (diff) | |
| download | linux-39d114ddc68223022c12ae3a1573912bc4b585e5.tar.xz | |
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.S | 3 | ||||
| -rw-r--r-- | arch/arm64/lib/memmove.S | 7 | ||||
| -rw-r--r-- | arch/arm64/lib/memset.S | 3 |
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) |