Messages in this thread | | | Date | Wed, 9 Oct 2019 17:58:47 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 1/6] x86/fpu/xstate: Fix small issues before adding supervisor xstates |
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On Wed, Sep 25, 2019 at 08:10:17AM -0700, Yu-cheng Yu wrote: > In response to earlier comments, fix small issues before introducing XSAVES > supervisor states: > - Add spaces around '*'. > - Fix comments of xfeature_is_supervisor(). > - Replace ((u64)1 << 63) with XCOMP_BV_COMPACTED_FORMAT. > > No functional changes from this patch. > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> > Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> > Reviewed-by: Tony Luck <tony.luck@intel.com> > --- > arch/x86/kernel/fpu/xstate.c | 15 ++++++--------- > 1 file changed, 6 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c > index e5cb67d67c03..b793fc2156b9 100644 > --- a/arch/x86/kernel/fpu/xstate.c > +++ b/arch/x86/kernel/fpu/xstate.c > @@ -60,7 +60,7 @@ u64 xfeatures_mask __read_mostly; > > static unsigned int xstate_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; > static unsigned int xstate_sizes[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1}; > -static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8]; > +static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask) * 8]; > > /* > * The XSAVE area of kernel can be in standard or compacted format; > @@ -110,12 +110,8 @@ EXPORT_SYMBOL_GPL(cpu_has_xfeatures); > static int xfeature_is_supervisor(int xfeature_nr) > { > /* > - * We currently do not support supervisor states, but if > - * we did, we could find out like this. > - * > - * SDM says: If state component 'i' is a user state component, > - * ECX[0] return 0; if state component i is a supervisor > - * state component, ECX[0] returns 1. > + * Extended State Enumeration Sub-leaves (EAX = 0DH, ECX = n, n > 1) > + * returns ECX[0] set to (1) for a supervisor state.
"... and cleared (0) for a user state."
I believe it is is clearer this way.
> */ > u32 eax, ebx, ecx, edx; >
Since you're touching this function: make it return bool as it is used in boolean context only and have it return simply:
return ecx & 1;
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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