On 11/17/2015 05:58 PM, Suzuki K. Poulose wrote:
> On 16/11/15 15:34, Andrey Ryabinin wrote:
>> On 11/16/2015 02:16 PM, Suzuki K. Poulose wrote:
>>> On 13/10/15 09:34, Catalin Marinas wrote:
>>>> On Mon, Oct 12, 2015 at 06:52:56PM +0300, Andrey Ryabinin wrote:
>
>>> Hi,
>>>
>>> I get the following failure with KASAN + 16K_PAGES + 48BIT_VA, with 4.4-rc1:
>>>
>>>
>>> arch/arm64/mm/kasan_init.c: In function ‘kasan_early_init’:
>>> include/linux/compiler.h:484:38: error: call to ‘__compiletime_assert_95’ declared with attribute error: BUILD_BUG_ON failed: !IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)
>>> _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
>>> ^
>
> ...
>
>>
>> Yes, it's really needed, because some code relies on this (e.g. clear_pgs() and kasan_init()).
>> But it should be possible to get rid of this requirement.
>
> And the other important point I missed mentioning was that, my tool chain doesn't
> support KASAN. But still the KASAN support files are still compiled and generates
> the above error. Shouldn't we disable it at build time if we detect that compiler
> doesn't support it ? Something like we do for LSE_ATOMICS.
>
We should either add proper Kconfig dependency for now, or just make it work.
From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Subject: [PATCH] arm64: KASAN depends on !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
On KASAN + 16K_PAGES + 48BIT_VA
arch/arm64/mm/kasan_init.c: In function ‘kasan_early_init’:
include/linux/compiler.h:484:38: error: call to ‘__compiletime_assert_95’ declared with attribute error: BUILD_BUG_ON failed: !IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)
_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
Currently KASAN will not work on 16K_PAGES and 48BIT_VA, so
forbid such configuration to avoid above build failure.
Reported-by: Suzuki K. Poulose <Suzuki.Poulose@xxxxxxx>
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
---
arch/arm64/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9ac16a4..bf7de69 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -49,7 +49,7 @@ config ARM64
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_BITREVERSE
select HAVE_ARCH_JUMP_LABEL
- select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP
+ select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP && !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
select HAVE_ARCH_KGDB
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
--
2.4.10
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