Thread (4 messages) 4 messages, 2 authors, 2018-11-27

[PATCH v2 1/2] arm64: add workaround for ambiguous C99 stdint.h types

From: Ard Biesheuvel <hidden>
Date: 2018-11-27 08:18:09
Also in: linux-block

On Tue, 27 Nov 2018 at 06:28, Jackie Liu [off-list ref] wrote:
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]
OK, I remember now :-)

So this is the reason you had two separate source files in the
previous revision.

Could we maybe deal with this differently? Could we add a header

arch/arm64/include/asm/neon-intrinsics.h

that includes <arm_neon.h> after setting the preprocessor overrides
below? And reference that header from your code?

That way, we don't have to override asm/types.h for everyone.


quoted hunk ↗ jump to hunk
Signed-off-by: Jackie Liu <redacted>
---
 arch/arm64/include/uapi/asm/types.h | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 arch/arm64/include/uapi/asm/types.h
diff --git a/arch/arm64/include/uapi/asm/types.h b/arch/arm64/include/uapi/asm/types.h
new file mode 100644
index 0000000..0016780
--- /dev/null
+++ b/arch/arm64/include/uapi/asm/types.h
@@ -0,0 +1,26 @@
+#ifndef _UAPI_ASM_TYPES_H
+#define _UAPI_ASM_TYPES_H
+
+#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.
+ */
+
+#ifdef __INT64_TYPE__
+#undef __INT64_TYPE__
+#define __INT64_TYPE__         __signed__ long long
+#endif
+
+#ifdef __UINT64_TYPE__
+#undef __UINT64_TYPE__
+#define __UINT64_TYPE__                unsigned long long
+#endif
+
+#endif /* _UAPI_ASM_TYPES_H */
--
2.7.4


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