Commit 28f7e66f authored Sep 08, 2008 by H. Peter Anvin

x86: prevent binutils from being "smart" and generating NOPLs for us



binutils, contrary to documented behaviour, will generate long NOPs (a
P6-or-higher instruction which is broken on at least some VIA chips,
Virtual PC/Virtual Server, and some versions of Qemu) depending on the
-mtune= option, which is not supposed to change architectural
behaviour.

Pass an explicit override to the assembler, in case ends up passing
the -mtune= parameter to gas (gcc 4.3.0 does not appear to.)

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

parent 43789e21

arch/x86/Makefile_32.cpu

+5 −0

Original line number	Diff line number	Diff line
		@@ -45,3 +45,8 @@ cflags-$(CONFIG_MGEODEGX1) += -march=pentium-mmx
		# cpu entries
		cflags-$(CONFIG_X86_GENERIC) += $(call tune,generic,$(call tune,i686))

		# Bug fix for binutils: this option is required in order to keep
		# binutils from generating NOPL instructions against our will.
		ifneq ($(CONFIG_X86_P6_NOP),y)
		cflags-y += $(call cc-option,-Wa$(comma)-mtune=generic32,)
		endif