Re: [PATCH v5 1/2] arm64/neon: add workaround for ambiguous C99 stdint.h types
From: Will Deacon <hidden>
Date: 2018-12-03 19:22:52
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On Wed, Nov 28, 2018 at 09:09:00AM +0800, Jackie Liu wrote:
quoted hunk ↗ jump to hunk
In a way similar to ARM commit 09096f6a0ee2 ("ARM: 7822/1: add workaround for ambiguous C99 stdint.h types"), this patch redefines the macros that are used in stdint.h so its definitions of uint64_t and int64_t are compatible with those of the kernel. This patch comes from: https://patchwork.kernel.org/patch/3540001/ Wrote by: Ard Biesheuvel [off-list ref] We mark this file as a private file and don't have to override asm/types.h Reviewed-by: Ard Biesheuvel <redacted> Signed-off-by: Jackie Liu <redacted> --- arch/arm64/include/asm/neon-intrinsics.h | 34 ++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 arch/arm64/include/asm/neon-intrinsics.hdiff --git a/arch/arm64/include/asm/neon-intrinsics.h b/arch/arm64/include/asm/neon-intrinsics.h new file mode 100644 index 0000000..e378766 --- /dev/null +++ b/arch/arm64/include/asm/neon-intrinsics.h@@ -0,0 +1,34 @@ +#ifndef _NEON_INTRINSICS_H +#define _NEON_INTRINSICS_H
We tend to name these with an __ASM_ prefix, so it should be: #ifndef __ASM_NEON_INTRINSICS_H That said, I notice that the commit you refer to for arch/arm/ actually places this stuff under uapi/. Is that needed?
+#include <asm-generic/int-ll64.h> + +/* + * For Aarch64, there is some ambiguity in the definition of the types below + * between the kernel and GCC itself. This is usually not a big deal, but it + * causes trouble when including GCC's version of 'stdint.h' (this is the file + * that gets included when you #include <stdint.h> on a -ffreestanding build). + * As this file also gets included implicitly when including 'arm_neon.h' (the + * NEON intrinsics support header), we need the following to work around the + * issue if we want to use NEON intrinsics in the kernel. + */
Could you elaborate on what the ambiguities / conflicts in the types are please? I think you can also remove the sentence about directly including stdint on a freestanding build, since it doesn't seem relevant to the kernel afaict (we only pull it in via arm_neon.h).
+ +#ifdef __INT64_TYPE__ +#undef __INT64_TYPE__ +#define __INT64_TYPE__ __signed__ long long
Do we need this __signed__ part? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel