On 10/08/2015 07:07 PM, Andrey Ryabinin wrote:

2015-10-08 18:11 GMT+03:00 Catalin Marinas [off-list ref]:

quoted

On Thu, Oct 08, 2015 at 02:09:26PM +0200, Ard Biesheuvel wrote:

quoted

On 8 October 2015 at 13:23, Andrey Ryabinin [off-list ref] wrote:

quoted

On 10/08/2015 02:11 PM, Mark Rutland wrote:

quoted

On Thu, Oct 08, 2015 at 01:36:09PM +0300, Andrey Ryabinin wrote:

quoted

2015-10-07 13:04 GMT+03:00 Catalin Marinas [off-list ref]:

quoted

On Thu, Sep 17, 2015 at 12:38:06PM +0300, Andrey Ryabinin wrote:

quoted

As usual patches available in git
      git://github.com/aryabinin/linux.git kasan/arm64v6

Changes since v5:
 - Rebase on top of 4.3-rc1
 - Fixed EFI boot.
 - Updated Doc/features/KASAN.

I tried to merge these patches (apart from the x86 one which is already
merged) but it still doesn't boot on Juno as an EFI application.

4.3-rc1 was ok and 4.3-rc4 is not. Break caused by 0ce3cc008ec04
("arm64/efi: Fix boot crash by not padding between EFI_MEMORY_RUNTIME
regions")
It introduced sort() call in efi_get_virtmap().
sort() is generic kernel function and it's instrumented, so we crash
when KASAN tries to access shadow in sort().

I believe this is solved by Ard's stub isolation series [1,2], which
will build a stub-specific copy of sort() and various other functions
(see the arm-deps in [2]).

So long as the stub is not built with ASAN, that should work.

Thanks, this should help, as we already build the stub without ASAN instrumentation.

Indeed. I did not mention instrumentation in the commit log for those
patches, but obviously, something like KASAN instrumentation cannot be
tolerated in the stub since it makes assumptions about the memory
layout

I'll review your latest EFI stub isolation patches and try Kasan again
on top (most likely tomorrow).

You'd better wait for v7, because kasan patches will need some adjustment.
Since stub is isolated,  we need to handle memcpy vs __memcpy stuff the same
way as we do in x86. Now we also need to #undef memset/memcpy/memmove in ARM64
(just like this was done for x86).

Hm, I was wrong, we don't need that.

I thought the EFI stub isolation patches create a copy of mem*() functions in the stub,
but they are just create aliases with __efistub_ prefix.

We only need to create some more aliases for KASAN.
The following patch on top of the EFI stub isolation series works for me.


Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
---
 arch/arm64/kernel/image.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index e083af0..6eb8fee 100644
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h

@@ -80,6 +80,12 @@ __efistub_strcmp		= __pi_strcmp;
 __efistub_strncmp		= __pi_strncmp;
 __efistub___flush_dcache_area	= __pi___flush_dcache_area;
 
+#ifdef CONFIG_KASAN
+__efistub___memcpy		= __pi_memcpy;
+__efistub___memmove		= __pi_memmove;
+__efistub___memset		= __pi_memset;
+#endif
+
 __efistub__text			= _text;
 __efistub__end			= _end;
 __efistub__edata		= _edata;

-- 
2.4.9