2015-10-31 09:29:57 +00:00
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From 71a0a72456b48de972d7ed613b06a22a3aa9057f Mon Sep 17 00:00:00 2001
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From: Yousong Zhou <yszhou4tech@gmail.com>
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Date: Sat, 26 Sep 2015 13:41:43 +0800
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Subject: [PATCH] MIPS: UAPI: Ignore __arch_swab{16,32,64} when using MIPS16
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Some GCC versions (e.g. 4.8.3) can incorrectly inline a function with
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MIPS32 instructions into another function with MIPS16 code [1], causing
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the assembler to genereate incorrect binary code or fail right away
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complaining about unrecognized opcode.
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In the case of __arch_swab{16,32}, when inlined by the compiler with
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flags `-mips32r2 -mips16 -Os', the assembler can fail with the following
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error.
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{standard input}:79: Error: unrecognized opcode `wsbh $2,$2'
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For performance concerns and to workaround the issue already existing in
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older compilers, just ignore these 2 functions when compiling with
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mips16 enabled.
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[1] Inlining nomips16 function into mips16 function can result in
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undefined builtins, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55777
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Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>
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Cc: Maciej W. Rozycki <macro@linux-mips.org>
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Cc: linux-mips@linux-mips.org
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Patchwork: https://patchwork.linux-mips.org/patch/11241/
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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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---
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arch/mips/include/uapi/asm/swab.h | 7 ++++---
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1 file changed, 4 insertions(+), 3 deletions(-)
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--- a/arch/mips/include/uapi/asm/swab.h
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+++ b/arch/mips/include/uapi/asm/swab.h
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@@ -13,8 +13,9 @@
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#define __SWAB_64_THRU_32__
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-#if (defined(__mips_isa_rev) && (__mips_isa_rev >= 2)) || \
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- defined(_MIPS_ARCH_LOONGSON3A)
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+#if !defined(__mips16) && \
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+ ((defined(__mips_isa_rev) && (__mips_isa_rev >= 2)) || \
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+ defined(_MIPS_ARCH_LOONGSON3A))
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static inline __attribute_const__ __u16 __arch_swab16(__u16 x)
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{
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2015-11-01 00:04:21 +00:00
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@@ -65,5 +66,5 @@ static inline __attribute_const__ __u64
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2015-10-31 09:29:57 +00:00
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}
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#define __arch_swab64 __arch_swab64
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#endif /* __mips64 */
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-#endif /* MIPS R2 or newer or Loongson 3A */
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+#endif /* (not __mips16) and (MIPS R2 or newer or Loongson 3A) */
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#endif /* _ASM_SWAB_H */
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