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- From 71a0a72456b48de972d7ed613b06a22a3aa9057f Mon Sep 17 00:00:00 2001
- From: Yousong Zhou <yszhou4tech@gmail.com>
- Date: Sat, 26 Sep 2015 13:41:43 +0800
- Subject: [PATCH] MIPS: UAPI: Ignore __arch_swab{16,32,64} when using MIPS16
- Some GCC versions (e.g. 4.8.3) can incorrectly inline a function with
- MIPS32 instructions into another function with MIPS16 code [1], causing
- the assembler to genereate incorrect binary code or fail right away
- complaining about unrecognized opcode.
- In the case of __arch_swab{16,32}, when inlined by the compiler with
- flags `-mips32r2 -mips16 -Os', the assembler can fail with the following
- error.
- {standard input}:79: Error: unrecognized opcode `wsbh $2,$2'
- For performance concerns and to workaround the issue already existing in
- older compilers, just ignore these 2 functions when compiling with
- mips16 enabled.
- [1] Inlining nomips16 function into mips16 function can result in
- undefined builtins, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55777
- Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>
- Cc: Maciej W. Rozycki <macro@linux-mips.org>
- Cc: linux-mips@linux-mips.org
- Patchwork: https://patchwork.linux-mips.org/patch/11241/
- Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
- ---
- arch/mips/include/uapi/asm/swab.h | 7 ++++---
- 1 file changed, 4 insertions(+), 3 deletions(-)
- --- a/arch/mips/include/uapi/asm/swab.h
- +++ b/arch/mips/include/uapi/asm/swab.h
- @@ -13,8 +13,9 @@
-
- #define __SWAB_64_THRU_32__
-
- -#if (defined(__mips_isa_rev) && (__mips_isa_rev >= 2)) || \
- - defined(_MIPS_ARCH_LOONGSON3A)
- +#if !defined(__mips16) && \
- + ((defined(__mips_isa_rev) && (__mips_isa_rev >= 2)) || \
- + defined(_MIPS_ARCH_LOONGSON3A))
-
- static inline __attribute_const__ __u16 __arch_swab16(__u16 x)
- {
- @@ -65,5 +66,5 @@ static inline __attribute_const__ __u64
- }
- #define __arch_swab64 __arch_swab64
- #endif /* __mips64 */
- -#endif /* MIPS R2 or newer or Loongson 3A */
- +#endif /* (not __mips16) and (MIPS R2 or newer or Loongson 3A) */
- #endif /* _ASM_SWAB_H */
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