[PATCH] ARM: add workaround for ambiguous C99 stdint.h types
Ard Biesheuvel
ard.biesheuvel at linaro.org
Thu Aug 15 08:45:46 EDT 2013
The C99 types uintXX_t that are usually defined in 'stdint.h' are not as
unambiguous on ARM as you would expect. For the types below, there is a
difference on ARM between GCC built for bare metal ARM, GCC built for glibc
and the kernel itself, which results in build errors if you try to build with
-ffreestanding and include 'stdint.h' (such as when you include 'arm_neon.h'
in order to use NEON intrinsics)
As the typedefs for these types in 'stdint.h' are based on builtin defines
supplied by GCC, we can tweak these to align with the kernel's idea of those
types, so 'linux/types.h' and 'stdint.h' can be safely included from the same
source file (provided that -ffreestanding is used).
int32_t uint32_t uintptr_t
bare metal GCC long unsigned long unsigned long
glibc GCC int unsigned int unsigned int
kernel int unsigned int unsigned long
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Acked-by: Nicolas Pitre <nico at linaro.org>
---
Hello Russell,
Would you please consider merging this patch?
It allows NEON intrinsics code to access kernel data structures (that typically
depend on linux/types.h), avoiding the need for messy workarounds. No other
kernel code uses these macros, so nothing else should be affected.
Regards,
Ard.
arch/arm/include/asm/types.h | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
create mode 100644 arch/arm/include/asm/types.h
diff --git a/arch/arm/include/asm/types.h b/arch/arm/include/asm/types.h
new file mode 100644
index 0000000..c4f0bca
--- /dev/null
+++ b/arch/arm/include/asm/types.h
@@ -0,0 +1,40 @@
+#ifndef _ASM_TYPES_H
+#define _ASM_TYPES_H
+
+#include <asm-generic/int-ll64.h>
+
+/*
+ * The C99 types uintXX_t that are usually defined in 'stdint.h' are not as
+ * unambiguous on ARM as you would expect. For the types below, there is a
+ * difference on ARM between GCC built for bare metal ARM, GCC built for glibc
+ * and the kernel itself, which results in build errors if you try to build with
+ * -ffreestanding and include 'stdint.h' (such as when you include 'arm_neon.h'
+ * in order to use NEON intrinsics)
+ *
+ * As the typedefs for these types in 'stdint.h' are based on builtin defines
+ * supplied by GCC, we can tweak these to align with the kernel's idea of those
+ * types, so 'linux/types.h' and 'stdint.h' can be safely included from the same
+ * source file (provided that -ffreestanding is used).
+ *
+ * int32_t uint32_t uintptr_t
+ * bare metal GCC long unsigned long unsigned long
+ * glibc GCC int unsigned int unsigned int
+ * kernel int unsigned int unsigned long
+ */
+
+#ifdef __INT32_TYPE__
+#undef __INT32_TYPE__
+#define __INT32_TYPE__ int
+#endif
+
+#ifdef __UINT32_TYPE__
+#undef __UINT32_TYPE__
+#define __UINT32_TYPE__ unsigned int
+#endif
+
+#ifdef __UINTPTR_TYPE__
+#undef __UINTPTR_TYPE__
+#define __UINTPTR_TYPE__ unsigned long
+#endif
+
+#endif /* _ASM_TYPES_H */
--
1.8.1.2
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