Re: [PATCH] x86/asm: fix gcc-5 enqcmds() build failure

From: H. Peter Anvin
Date: Mon Aug 02 2021 - 12:48:46 EST


NAK.

The type of arguments to condition code arguments should be bool.

On August 2, 2021 4:53:42 PM GMT+02:00, Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>From: Arnd Bergmann <arnd@xxxxxxxx>
>
>Building drivers/dma/idxd/submit.o with gcc-5.5 results in a cryptic
>error messages:
>
>arch/x86/include/asm/special_insns.h: Assembler messages:
>arch/x86/include/asm/special_insns.h:286: Error: operand size mismatch for `setz'
>make[5]: *** [scripts/Makefile.build:272: drivers/dma/idxd/submit.o] Error 1
>
>It seems that this happens for 32-bit arguments when the instruction
>expects an 8-bit argument. Change the type of the local variable
>accordingly to get a clean build.
>
>Fixes: 7f5933f81bd8 ("x86/asm: Add an enqcmds() wrapper for the ENQCMDS instruction")
>Fixes: 8e50d392652f ("dmaengine: idxd: Add shared workqueue support") # guessed
>Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
>---
> arch/x86/include/asm/special_insns.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
>index f3fbb84ff8a7..33264839f99e 100644
>--- a/arch/x86/include/asm/special_insns.h
>+++ b/arch/x86/include/asm/special_insns.h
>@@ -275,7 +275,7 @@ static inline int enqcmds(void __iomem *dst, const void *src)
> {
> const struct { char _[64]; } *__src = src;
> struct { char _[64]; } __iomem *__dst = dst;
>- int zf;
>+ u8 zf;
>
> /*
> * ENQCMDS %(rdx), rax

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