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x86/fpu: Move XSAVE-disabling code to a helper 

When we want to _completely_ disable XSAVE support as far as
the kernel is concerned, we have a big set of feature flags
to clear.  We currently only do this in cases where the user
asks for it to be disabled, but we are about to expand the
places where we do it to handle errors too.

Move the code in to xstate.c, and put it in the xstate.h
header.  We will use it in the next patch too.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: dave@sr71.net
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20150902233124.EA9A70E5@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dave Hansen 2015-09-02 16:31:24 -07:00 committed by Ingo Molnar
parent b081535959
commit 0a26537502
3 changed files with 21 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/fpu/xstate.h
View File

@ -40,6 +40,7 @@ extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask);
void fpu__xstate_clear_all_cpu_caps(void);
void *get_xsave_addr(struct xregs_state *xsave, int xstate);
const void *get_xsave_field_ptr(int xstate_field);

12
arch/x86/kernel/fpu/init.c
View File

@ -354,17 +354,7 @@ static int __init x86_noxsave_setup(char *s)
if (strlen(s))
return 0;
setup_clear_cpu_cap(X86_FEATURE_XSAVE);
setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
setup_clear_cpu_cap(X86_FEATURE_XSAVEC);
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
setup_clear_cpu_cap(X86_FEATURE_AVX);
setup_clear_cpu_cap(X86_FEATURE_AVX2);
setup_clear_cpu_cap(X86_FEATURE_AVX512F);
setup_clear_cpu_cap(X86_FEATURE_AVX512PF);
setup_clear_cpu_cap(X86_FEATURE_AVX512ER);
setup_clear_cpu_cap(X86_FEATURE_AVX512CD);
setup_clear_cpu_cap(X86_FEATURE_MPX);
fpu__xstate_clear_all_cpu_caps();
return 1;
}

19
arch/x86/kernel/fpu/xstate.c
View File

@ -38,6 +38,25 @@ static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
/* The number of supported xfeatures in xfeatures_mask: */
static unsigned int xfeatures_nr;
/*
* Clear all of the X86_FEATURE_* bits that are unavailable
* when the CPU has no XSAVE support.
*/
void fpu__xstate_clear_all_cpu_caps(void)
{
setup_clear_cpu_cap(X86_FEATURE_XSAVE);
setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
setup_clear_cpu_cap(X86_FEATURE_XSAVEC);
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
setup_clear_cpu_cap(X86_FEATURE_AVX);
setup_clear_cpu_cap(X86_FEATURE_AVX2);
setup_clear_cpu_cap(X86_FEATURE_AVX512F);
setup_clear_cpu_cap(X86_FEATURE_AVX512PF);
setup_clear_cpu_cap(X86_FEATURE_AVX512ER);
setup_clear_cpu_cap(X86_FEATURE_AVX512CD);
setup_clear_cpu_cap(X86_FEATURE_MPX);
}
/*
* Return whether the system supports a given xfeature.
*