From 71a0a72456b48de972d7ed613b06a22a3aa9057f Mon Sep 17 00:00:00 2001 From: Yousong Zhou 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 Cc: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11241/ Signed-off-by: Ralf Baechle --- 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 */