lkml.org 
[lkml]   [2010]   [Aug]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:x86/fpu] x86, xsave: Disable xsave in i387 emulation mode
    Commit-ID:  1f999ab5a1360afc388868cc0ef9afe8edeef3be
    Gitweb: http://git.kernel.org/tip/1f999ab5a1360afc388868cc0ef9afe8edeef3be
    Author: Robert Richter <robert.richter@amd.com>
    AuthorDate: Wed, 21 Jul 2010 19:03:57 +0200
    Committer: H. Peter Anvin <hpa@linux.intel.com>
    CommitDate: Thu, 12 Aug 2010 14:16:54 -0700

    x86, xsave: Disable xsave in i387 emulation mode

    xsave is broken for (!HAVE_HWFP). This is the case if config
    MATH_EMULATION is enabled, 'no387' kernel parameter is set and xsave
    exists. xsave will not work because x86/math-emu and xsave share the
    same memory. As this case can be treated as corner case we simply
    disable xsave then.

    Signed-off-by: Robert Richter <robert.richter@amd.com>
    LKML-Reference: <1279731838-1522-7-git-send-email-robert.richter@amd.com>
    Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
    ---
    arch/x86/kernel/i387.c | 6 ++++++
    1 files changed, 6 insertions(+), 0 deletions(-)

    diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
    index 1f11f5c..2605c50 100644
    --- a/arch/x86/kernel/i387.c
    +++ b/arch/x86/kernel/i387.c
    @@ -67,6 +67,12 @@ static void __cpuinit init_thread_xstate(void)
    */

    if (!HAVE_HWFP) {
    + /*
    + * Disable xsave as we do not support it if i387
    + * emulation is enabled.
    + */
    + setup_clear_cpu_cap(X86_FEATURE_XSAVE);
    + setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
    xstate_size = sizeof(struct i387_soft_struct);
    return;
    }

    \
     
     \ /
      Last update: 2010-08-13 00:09    [W:0.041 / U:29.744 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site