* [PATCH] arm64: lse: Fix LSE atomics with LLVM
@ 2020-02-18 16:49 Vincenzo Frascino
2020-02-18 16:54 ` Will Deacon
0 siblings, 1 reply; 7+ messages in thread
From: Vincenzo Frascino @ 2020-02-18 16:49 UTC (permalink / raw)
To: linux-arm-kernel, clang-built-linux
Cc: amit.kachhap, catalin.marinas, will.deacon
The introduction of the commit e0d5896bd356cd broke the compilation of
the kernel when the selected compiler is clang and it is used in
combination with "-no-integrated-as".
This happens because __LSE_PREAMBLE is defined as ".arch armv8-a+lse"
and this overrides the version of the architecture passed via -march
command line to the gas compiler.
The issue was noticed during the development of pauth on arm64 and an
error example is reported below:
$ aarch64-none-linux-gnu-as -EL -I ./arch/arm64/include
-I ./arch/arm64/include/generated
-I ./include -I ./include
-I ./arch/arm64/include/uapi
-I ./arch/arm64/include/generated/uapi
-I ./include/uapi -I ./include/generated/uapi
-I ./init -I ./init
-march=armv8.3-a -o init/do_mounts.o
/tmp/do_mounts-d7992a.s
/tmp/do_mounts-d7992a.s: Assembler messages:
/tmp/do_mounts-d7992a.s:1959: Error: selected processor does not support `autiasp'
/tmp/do_mounts-d7992a.s:2021: Error: selected processor does not support `paciasp'
/tmp/do_mounts-d7992a.s:2157: Error: selected processor does not support `autiasp'
/tmp/do_mounts-d7992a.s:2175: Error: selected processor does not support `paciasp'
/tmp/do_mounts-d7992a.s:2494: Error: selected processor does not support `autiasp'
Fix the issue replacing ".arch armv8-a+lse" with ".arch_extension lse" that does
not override the command line parameter.
Fixes: e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated assembler")
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reported-by: Amit Kachhap <Amit.Kachhap@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
arch/arm64/include/asm/lse.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/lse.h b/arch/arm64/include/asm/lse.h
index d429f7701c36..5d10051c3e62 100644
--- a/arch/arm64/include/asm/lse.h
+++ b/arch/arm64/include/asm/lse.h
@@ -6,7 +6,7 @@
#ifdef CONFIG_ARM64_LSE_ATOMICS
-#define __LSE_PREAMBLE ".arch armv8-a+lse\n"
+#define __LSE_PREAMBLE ".arch_extension lse\n"
#include <linux/compiler_types.h>
#include <linux/export.h>
--
2.25.0
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^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] arm64: lse: Fix LSE atomics with LLVM
2020-02-18 16:49 [PATCH] arm64: lse: Fix LSE atomics with LLVM Vincenzo Frascino
@ 2020-02-18 16:54 ` Will Deacon
2020-02-18 17:42 ` Vincenzo Frascino
2020-02-18 18:02 ` Sami Tolvanen
0 siblings, 2 replies; 7+ messages in thread
From: Will Deacon @ 2020-02-18 16:54 UTC (permalink / raw)
To: Vincenzo Frascino
Cc: catalin.marinas, will.deacon, clang-built-linux, samitolvanen,
amit.kachhap, linux-arm-kernel
[+Sami]
On Tue, Feb 18, 2020 at 04:49:06PM +0000, Vincenzo Frascino wrote:
> The introduction of the commit e0d5896bd356cd broke the compilation of
> the kernel when the selected compiler is clang and it is used in
> combination with "-no-integrated-as".
Curious, but have you tested this change with the integrated assembler as
well?
> This happens because __LSE_PREAMBLE is defined as ".arch armv8-a+lse"
> and this overrides the version of the architecture passed via -march
> command line to the gas compiler.
>
> The issue was noticed during the development of pauth on arm64 and an
> error example is reported below:
>
> $ aarch64-none-linux-gnu-as -EL -I ./arch/arm64/include
> -I ./arch/arm64/include/generated
> -I ./include -I ./include
> -I ./arch/arm64/include/uapi
> -I ./arch/arm64/include/generated/uapi
> -I ./include/uapi -I ./include/generated/uapi
> -I ./init -I ./init
> -march=armv8.3-a -o init/do_mounts.o
> /tmp/do_mounts-d7992a.s
> /tmp/do_mounts-d7992a.s: Assembler messages:
> /tmp/do_mounts-d7992a.s:1959: Error: selected processor does not support `autiasp'
> /tmp/do_mounts-d7992a.s:2021: Error: selected processor does not support `paciasp'
> /tmp/do_mounts-d7992a.s:2157: Error: selected processor does not support `autiasp'
> /tmp/do_mounts-d7992a.s:2175: Error: selected processor does not support `paciasp'
> /tmp/do_mounts-d7992a.s:2494: Error: selected processor does not support `autiasp'
>
> Fix the issue replacing ".arch armv8-a+lse" with ".arch_extension lse" that does
> not override the command line parameter.
>
> Fixes: e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated assembler")
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Reported-by: Amit Kachhap <Amit.Kachhap@arm.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> ---
> arch/arm64/include/asm/lse.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/lse.h b/arch/arm64/include/asm/lse.h
> index d429f7701c36..5d10051c3e62 100644
> --- a/arch/arm64/include/asm/lse.h
> +++ b/arch/arm64/include/asm/lse.h
> @@ -6,7 +6,7 @@
>
> #ifdef CONFIG_ARM64_LSE_ATOMICS
>
> -#define __LSE_PREAMBLE ".arch armv8-a+lse\n"
> +#define __LSE_PREAMBLE ".arch_extension lse\n"
I'm ok with this, but Sami assumedly changed this for a reason in
e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated
assembler").
Sami?
Will
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] arm64: lse: Fix LSE atomics with LLVM
2020-02-18 16:54 ` Will Deacon
@ 2020-02-18 17:42 ` Vincenzo Frascino
2020-02-18 18:03 ` Sami Tolvanen
2020-02-18 18:02 ` Sami Tolvanen
1 sibling, 1 reply; 7+ messages in thread
From: Vincenzo Frascino @ 2020-02-18 17:42 UTC (permalink / raw)
To: Will Deacon
Cc: catalin.marinas, will.deacon, clang-built-linux, samitolvanen,
amit.kachhap, linux-arm-kernel
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Hi Will,
On 18/02/2020 16:54, Will Deacon wrote:
> [+Sami]
>
Thanks for this, I forgot to add Sami in Cc.
> On Tue, Feb 18, 2020 at 04:49:06PM +0000, Vincenzo Frascino wrote:
>> The introduction of the commit e0d5896bd356cd broke the compilation of
>> the kernel when the selected compiler is clang and it is used in
>> combination with "-no-integrated-as".
>
> Curious, but have you tested this change with the integrated assembler as
> well?
>
The integrated assembler as far as I am aware cannot assemble the kernel for
reasons independent from lse (AS=clang generates a lot of errors). Not sure how
Sami is testing it. I would be happy to learn it myself.
The default option for clang in the kernel Makefile is "-no-integrated-as"
though hence e0d5896bd356cd introduces a regression.
>> This happens because __LSE_PREAMBLE is defined as ".arch armv8-a+lse"
>> and this overrides the version of the architecture passed via -march
>> command line to the gas compiler.
>>
>> The issue was noticed during the development of pauth on arm64 and an
>> error example is reported below:
>>
>> $ aarch64-none-linux-gnu-as -EL -I ./arch/arm64/include
>> -I ./arch/arm64/include/generated
>> -I ./include -I ./include
>> -I ./arch/arm64/include/uapi
>> -I ./arch/arm64/include/generated/uapi
>> -I ./include/uapi -I ./include/generated/uapi
>> -I ./init -I ./init
>> -march=armv8.3-a -o init/do_mounts.o
>> /tmp/do_mounts-d7992a.s
>> /tmp/do_mounts-d7992a.s: Assembler messages:
>> /tmp/do_mounts-d7992a.s:1959: Error: selected processor does not support `autiasp'
>> /tmp/do_mounts-d7992a.s:2021: Error: selected processor does not support `paciasp'
>> /tmp/do_mounts-d7992a.s:2157: Error: selected processor does not support `autiasp'
>> /tmp/do_mounts-d7992a.s:2175: Error: selected processor does not support `paciasp'
>> /tmp/do_mounts-d7992a.s:2494: Error: selected processor does not support `autiasp'
>>
>> Fix the issue replacing ".arch armv8-a+lse" with ".arch_extension lse" that does
>> not override the command line parameter.
>>
>> Fixes: e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated assembler")
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Reported-by: Amit Kachhap <Amit.Kachhap@arm.com>
>> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
>> ---
>> arch/arm64/include/asm/lse.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/include/asm/lse.h b/arch/arm64/include/asm/lse.h
>> index d429f7701c36..5d10051c3e62 100644
>> --- a/arch/arm64/include/asm/lse.h
>> +++ b/arch/arm64/include/asm/lse.h
>> @@ -6,7 +6,7 @@
>>
>> #ifdef CONFIG_ARM64_LSE_ATOMICS
>>
>> -#define __LSE_PREAMBLE ".arch armv8-a+lse\n"
>> +#define __LSE_PREAMBLE ".arch_extension lse\n"
>
> I'm ok with this, but Sami assumedly changed this for a reason in
> e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated
> assembler").
>
> Sami?
>
> Will
>
--
Regards,
Vincenzo
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] arm64: lse: Fix LSE atomics with LLVM
2020-02-18 16:54 ` Will Deacon
2020-02-18 17:42 ` Vincenzo Frascino
@ 2020-02-18 18:02 ` Sami Tolvanen
2020-02-18 18:05 ` Will Deacon
1 sibling, 1 reply; 7+ messages in thread
From: Sami Tolvanen @ 2020-02-18 18:02 UTC (permalink / raw)
To: Will Deacon
Cc: Catalin Marinas, Will Deacon, clang-built-linux, amit.kachhap,
Vincenzo Frascino, linux-arm-kernel
On Tue, Feb 18, 2020 at 8:54 AM Will Deacon <will@kernel.org> wrote:
> > -#define __LSE_PREAMBLE ".arch armv8-a+lse\n"
> > +#define __LSE_PREAMBLE ".arch_extension lse\n"
>
> I'm ok with this, but Sami assumedly changed this for a reason in
> e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated
> assembler").
Correct, I changed this because clang's integrated assembler wasn't
happy with .arch_extension lse at the time. However, it looks like
current versions of clang don't have this problem, so this change
looks good to me.
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Sami
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] arm64: lse: Fix LSE atomics with LLVM
2020-02-18 17:42 ` Vincenzo Frascino
@ 2020-02-18 18:03 ` Sami Tolvanen
0 siblings, 0 replies; 7+ messages in thread
From: Sami Tolvanen @ 2020-02-18 18:03 UTC (permalink / raw)
To: Vincenzo Frascino
Cc: Catalin Marinas, Will Deacon, clang-built-linux, amit.kachhap,
Will Deacon, linux-arm-kernel
On Tue, Feb 18, 2020 at 9:43 AM Vincenzo Frascino
<vincenzo.frascino@arm.com> wrote:
> The integrated assembler as far as I am aware cannot assemble the kernel for
> reasons independent from lse (AS=clang generates a lot of errors). Not sure how
> Sami is testing it. I would be happy to learn it myself.
We use LTO in Android kernels, which flips on Clang's integrated
assembler for inline assembly only.
Sami
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] arm64: lse: Fix LSE atomics with LLVM
2020-02-18 18:02 ` Sami Tolvanen
@ 2020-02-18 18:05 ` Will Deacon
2020-02-18 18:11 ` Vincenzo Frascino
0 siblings, 1 reply; 7+ messages in thread
From: Will Deacon @ 2020-02-18 18:05 UTC (permalink / raw)
To: Sami Tolvanen
Cc: Catalin Marinas, Will Deacon, clang-built-linux, amit.kachhap,
Vincenzo Frascino, linux-arm-kernel
On Tue, Feb 18, 2020 at 10:02:24AM -0800, Sami Tolvanen wrote:
> On Tue, Feb 18, 2020 at 8:54 AM Will Deacon <will@kernel.org> wrote:
> > > -#define __LSE_PREAMBLE ".arch armv8-a+lse\n"
> > > +#define __LSE_PREAMBLE ".arch_extension lse\n"
> >
> > I'm ok with this, but Sami assumedly changed this for a reason in
> > e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated
> > assembler").
>
> Correct, I changed this because clang's integrated assembler wasn't
> happy with .arch_extension lse at the time. However, it looks like
> current versions of clang don't have this problem, so this change
> looks good to me.
>
> Tested-by: Sami Tolvanen <samitolvanen@google.com>
Cheers, I'll queue this with your tag.
Will
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] arm64: lse: Fix LSE atomics with LLVM
2020-02-18 18:05 ` Will Deacon
@ 2020-02-18 18:11 ` Vincenzo Frascino
0 siblings, 0 replies; 7+ messages in thread
From: Vincenzo Frascino @ 2020-02-18 18:11 UTC (permalink / raw)
To: Will Deacon, Sami Tolvanen
Cc: amit.kachhap, clang-built-linux, Will Deacon, linux-arm-kernel,
Catalin Marinas
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Hi Will and Sami,
On 18/02/2020 18:05, Will Deacon wrote:
> On Tue, Feb 18, 2020 at 10:02:24AM -0800, Sami Tolvanen wrote:
>> On Tue, Feb 18, 2020 at 8:54 AM Will Deacon <will@kernel.org> wrote:
>>>> -#define __LSE_PREAMBLE ".arch armv8-a+lse\n"
>>>> +#define __LSE_PREAMBLE ".arch_extension lse\n"
>>>
>>> I'm ok with this, but Sami assumedly changed this for a reason in
>>> e0d5896bd356cd ("arm64: lse: fix LSE atomics with LLVM's integrated
>>> assembler").
>>
>> Correct, I changed this because clang's integrated assembler wasn't
>> happy with .arch_extension lse at the time. However, it looks like
>> current versions of clang don't have this problem, so this change
>> looks good to me.
>>
>> Tested-by: Sami Tolvanen <samitolvanen@google.com>
>
> Cheers, I'll queue this with your tag.
>
> Will
>
Thank you for the quick turn around :)
--
Regards,
Vincenzo
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^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-02-18 18:12 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-18 16:49 [PATCH] arm64: lse: Fix LSE atomics with LLVM Vincenzo Frascino
2020-02-18 16:54 ` Will Deacon
2020-02-18 17:42 ` Vincenzo Frascino
2020-02-18 18:03 ` Sami Tolvanen
2020-02-18 18:02 ` Sami Tolvanen
2020-02-18 18:05 ` Will Deacon
2020-02-18 18:11 ` Vincenzo Frascino
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