x86, xsave: Disable xsave in i387 emulation mode
authorRobert Richter <robert.richter@amd.com>
Wed, 21 Jul 2010 17:03:57 +0000 (19:03 +0200)
committerH. Peter Anvin <hpa@linux.intel.com>
Thu, 12 Aug 2010 21:16:54 +0000 (14:16 -0700)
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

index 1f11f5ce668f93aadff67c425fae359da6efc6a8..2605c50b11d3a0e7708b0761f93eee9fe91295e4 100644 (file)
@@ -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;
        }