All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH v2 1/3] x86/hash: fix build failure with older binutils
@ 2014-02-27  8:47 Jan Beulich
  2014-02-27  9:26 ` Daniel Borkmann
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Jan Beulich @ 2014-02-27  8:47 UTC (permalink / raw)
  To: mingo, tglx, Jan Beulich, hpa
  Cc: davem, dborkman, ffusco, tgraf, linux-kernel

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).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Francesco Fusco <ffusco@redhat.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Thomas Graf <tgraf@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
---
 arch/x86/Makefile   |    1 +
 arch/x86/lib/hash.c |    4 ++++
 2 files changed, 5 insertions(+)

--- 3.14-rc4-x86-hash-crc32.orig/arch/x86/Makefile
+++ 3.14-rc4-x86-hash-crc32/arch/x86/Makefile
@@ -152,6 +152,7 @@ cfi-sections := $(call as-instr,.cfi_sec
 
 # 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)
 
--- 3.14-rc4-x86-hash-crc32.orig/arch/x86/lib/hash.c
+++ 3.14-rc4-x86-hash-crc32/arch/x86/lib/hash.c
@@ -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;
 }
 




^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2014-03-19 23:54 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-02-27  8:47 [PATCH v2 1/3] x86/hash: fix build failure with older binutils Jan Beulich
2014-02-27  9:26 ` Daniel Borkmann
2014-03-19 23:48 ` [tip:x86/hash] x86, hash: Fix " tip-bot for Jan Beulich
2014-03-19 23:54 ` tip-bot for Jan Beulich

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.