2021-07-27 14:14:01

by Pavo Banicevic

Subject: [PATCH 2/3] arm: include: asm: unified: mask .syntax unified for clang

From: Ivan Khoronzhuk <[email protected]>

The samples/bpf reuses linux headers, with clang -emit-llvm,
so this w/a is only for samples/bpf (samples/bpf/Makefile CLANG-bpf).

It allows to build samples/bpf for arm on target board.
In another way clang -emit-llvm generates errors like:

<inline asm>:1:1: error: unknown directive
.syntax unified

I have verified it on clang 5, 6, 7, 8, 9, 10
as on native platform as for cross-compiling. This decision is
arguable, but it doesn't have impact on samples/bpf so it's easier
just ignore it for clang, at least for now...

Signed-off-by: Ivan Khoronzhuk <[email protected]>
---
arch/arm/include/asm/unified.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/unified.h b/arch/arm/include/asm/unified.h
index 1e2c3eb04353..8718f313e7c4 100644
--- a/arch/arm/include/asm/unified.h
+++ b/arch/arm/include/asm/unified.h
@@ -11,7 +11,9 @@
#if defined(__ASSEMBLY__)
.syntax unified
#else
-__asm__(".syntax unified");
+
+#ifndef __clang__
+ __asm__(".syntax unified");
#endif

#ifdef CONFIG_CPU_V7M
--
2.32.0

2021-07-27 17:57:50

by Nick Desaulniers

Subject: Re: [PATCH 2/3] arm: include: asm: unified: mask .syntax unified for clang

On Tue, Jul 27, 2021 at 7:12 AM Pavo Banicevic
<[email protected]> wrote:
>
> From: Ivan Khoronzhuk <[email protected]>
>
> The samples/bpf reuses linux headers, with clang -emit-llvm,
> so this w/a is only for samples/bpf (samples/bpf/Makefile CLANG-bpf).
>
> It allows to build samples/bpf for arm on target board.
> In another way clang -emit-llvm generates errors like:
>
> <inline asm>:1:1: error: unknown directive
> .syntax unified
>
> I have verified it on clang 5, 6, 7, 8, 9, 10
> as on native platform as for cross-compiling. This decision is
> arguable, but it doesn't have impact on samples/bpf so it's easier
> just ignore it for clang, at least for now...

Did you test ARCH=arm kernel builds with Clang with this series applied?

>
> Signed-off-by: Ivan Khoronzhuk <[email protected]>
> ---
> arch/arm/include/asm/unified.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/unified.h b/arch/arm/include/asm/unified.h
> index 1e2c3eb04353..8718f313e7c4 100644
> --- a/arch/arm/include/asm/unified.h
> +++ b/arch/arm/include/asm/unified.h
> @@ -11,7 +11,9 @@
> #if defined(__ASSEMBLY__)
> .syntax unified
> #else
> -__asm__(".syntax unified");
> +
> +#ifndef __clang__
> + __asm__(".syntax unified");
> #endif
>
> #ifdef CONFIG_CPU_V7M
> --
> 2.32.0
>


--
Thanks,
~Nick Desaulniers