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Commit 06325190 authored by Jan Beulich's avatar Jan Beulich Committed by H. Peter Anvin
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x86, hash: Fix build failure with older binutils 



Just like for other ISA extension instruction uses we should check
whether the assembler actually supports them. The fallback here simply
is to encode an instruction  with fixed operands (%eax and %ecx).

[ hpa: tagging for -stable as a build fix ]

Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/530F0996020000780011FBE7@nat28.tlf.novell.com


Cc: Francesco Fusco <ffusco@redhat.com>
Cc: Thomas Graf <tgraf@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> # v3.14
parent dcb99fd9

arch/x86/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTI 


# does binutils support specific instructions?

asinstr := $(call as-instr,fxsaveq (%rax),-DCONFIG_AS_FXSAVEQ=1)

asinstr += $(call as-instr,crc32l %eax$(comma)%eax,-DCONFIG_AS_CRC32=1)

avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)

avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)

arch/x86/lib/hash.c

+4 −0
Original line number Diff line number Diff line
@@ -39,7 +39,11 @@ 


static inline u32 crc32_u32(u32 crc, u32 val)

{

#ifdef CONFIG_AS_CRC32

	asm ("crc32l %1,%0\n" : "+r" (crc) : "rm" (val));

#else

	asm (".byte 0xf2, 0x0f, 0x38, 0xf1, 0xc1" : "+a" (crc) : "c" (val));

#endif

	return crc;

}