diff options
| author | Yu-cheng Yu <yu-cheng.yu@intel.com> | 2016-07-11 09:18:57 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-07-11 16:44:01 +0200 |
| commit | b8be15d588060a03569ac85dc4a0247460988f5b (patch) | |
| tree | 1865d79291d95d28703879e73e963b764b46571b /arch/x86/kernel/fpu | |
| parent | 35ac2d7ba787eb4b7418a5a6f5919c25e10a780a (diff) | |
x86/fpu/xstate: Re-enable XSAVES
We did not handle XSAVES instructions correctly. There were issues in
converting between standard and compacted format when interfacing with
user-space. These issues have been corrected.
Add a WARN_ONCE() to make it clear that XSAVES supervisor states are not
yet implemented.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <h.peter.anvin@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468253937-40008-5-git-send-email-fenghua.yu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/fpu')
| -rw-r--r-- | arch/x86/kernel/fpu/init.c | 15 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 9 |
2 files changed, 9 insertions, 15 deletions
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 60f3839c5bfa..93982aebb398 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -230,21 +230,6 @@ static void __init fpu__init_system_xstate_size_legacy(void) } fpu_user_xstate_size = fpu_kernel_xstate_size; - - /* - * Quirk: we don't yet handle the XSAVES* instructions - * correctly, as we don't correctly convert between - * standard and compacted format when interfacing - * with user-space - so disable it for now. - * - * The difference is small: with recent CPUs the - * compacted format is only marginally smaller than - * the standard FPU state format. - * - * ( This is easy to backport while we are fixing - * XSAVES* support. ) - */ - setup_clear_cpu_cap(X86_FEATURE_XSAVES); } /* diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 4fb8dd7697c5..3169bcaf9391 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -221,6 +221,15 @@ void fpu__init_cpu_xstate(void) { if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask) return; + /* + * Make it clear that XSAVES supervisor states are not yet + * implemented should anyone expect it to work by changing + * bits in XFEATURE_MASK_* macros and XCR0. + */ + WARN_ONCE((xfeatures_mask & XFEATURE_MASK_SUPERVISOR), + "x86/fpu: XSAVES supervisor states are not yet implemented.\n"); + + xfeatures_mask &= ~XFEATURE_MASK_SUPERVISOR; cr4_set_bits(X86_CR4_OSXSAVE); xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask); |