lkml.org 
[lkml]   [2009]   [Dec]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:x86/urgent] x86, compress: Force i386 instructions for the decompressor
    Commit-ID:  17a2a9b57a9a7d2fd8f97df951b5e63e0bd56ef5
    Gitweb: http://git.kernel.org/tip/17a2a9b57a9a7d2fd8f97df951b5e63e0bd56ef5
    Author: H. Peter Anvin <hpa@zytor.com>
    AuthorDate: Fri, 25 Dec 2009 15:40:38 -0800
    Committer: H. Peter Anvin <hpa@zytor.com>
    CommitDate: Fri, 25 Dec 2009 15:40:38 -0800

    x86, compress: Force i386 instructions for the decompressor

    Recently, some distros have started shipping versions of gcc which
    default to -march=i686. This breaks building kernels for pre-i686
    machines, even if they have been selected in Kconfig, due to the
    generation of CMOV instructions.

    There isn't enough benefit to try to preserve the generation of these
    instructions even when selected, so simply force -march=i386 for the
    decompressor when building a 32-bit kernel.

    Reported-and-tested-by: Chris Rankin <rankincj@yahoo.com>
    Signed-off-by: H. Peter Anvin <hpa@zytor.com>
    LKML-Reference: <219280.97558.qm@web52907.mail.re2.yahoo.com>
    ---
    arch/x86/boot/compressed/Makefile | 1 +
    1 files changed, 1 insertions(+), 0 deletions(-)

    diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
    index f8ed065..f25bbd3 100644
    --- a/arch/x86/boot/compressed/Makefile
    +++ b/arch/x86/boot/compressed/Makefile
    @@ -9,6 +9,7 @@ targets := vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinu
    KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
    KBUILD_CFLAGS += -fno-strict-aliasing -fPIC
    KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
    +cflags-$(CONFIG_X86_32) := -march=i386
    cflags-$(CONFIG_X86_64) := -mcmodel=small
    KBUILD_CFLAGS += $(cflags-y)
    KBUILD_CFLAGS += $(call cc-option,-ffreestanding)

    \
     
     \ /
      Last update: 2009-12-26 01:51    [W:0.022 / U:151.668 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site