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Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull a x86/build change from Ingo Molnar.

This makes the default stack alignment on x86-64 be just 8, allowing for
improved code generation (it can avoid some unnecessary extra alignment
logic and use just pure push/pop sequences) and smaller stack frames.

We can't generally do SSE with 16-byte alignment issues in the kernel anyway.

* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86-64, gcc: Use -mpreferred-stack-boundary=3 if supported
Linus Torvalds před 13 roky
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e2b34e311b
1 změnil soubory, kde provedl 3 přidání a 0 odebrání
  1. 3 0
      arch/x86/Makefile

+ 3 - 0
arch/x86/Makefile

@@ -49,6 +49,9 @@ else
         KBUILD_AFLAGS += -m64
         KBUILD_CFLAGS += -m64
 
+	# Use -mpreferred-stack-boundary=3 if supported.
+	KBUILD_CFLAGS += $(call cc-option,-mno-sse -mpreferred-stack-boundary=3)
+
         # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
         cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
         cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)