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Subject[PATCH 08/15] x86, fpu: remove xfeature_nr
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From: Dave Hansen <dave.hansen@linux.intel.com>

xfeature_nr ended up being initialized too late for me to
use it in the "xsave size sanity check" patch which is
later in the series. I tried to move around its initialization
but realized that it was just as easy to get rid of it.

We only have 9 XFEATURES. Instead of dynamically calculating
and storing the last feature, just use the compile-time max:
XFEATURES_NR_MAX. Note that even with 'xfeatures_nr' we can
had "holes" in the xfeatures_mask that we had to deal with.

We also change a 'leaf' variable to be a plain 'i'. Although
it is used to grab a cpuid leaf in this one loop, all of the
other loops just use an 'i' and I find it much more obvious
to keep the naming consistent across all the similar loops.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
---

b/arch/x86/kernel/fpu/xstate.c | 24 ++++++++----------------
1 file changed, 8 insertions(+), 16 deletions(-)

diff -puN arch/x86/kernel/fpu/xstate.c~kill-xfeatures_nr arch/x86/kernel/fpu/xstate.c
--- a/arch/x86/kernel/fpu/xstate.c~kill-xfeatures_nr 2015-08-31 15:17:34.593891409 -0700
+++ b/arch/x86/kernel/fpu/xstate.c 2015-08-31 15:17:34.596891547 -0700
@@ -35,9 +35,6 @@ static unsigned int xstate_offsets[XFEAT
static unsigned int xstate_sizes[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1};
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.
@@ -190,23 +187,18 @@ void fpu__init_cpu_xstate(void)
/*
* Record the offsets and sizes of various xstates contained
* in the XSAVE state memory layout.
- *
- * ( Note that certain features might be non-present, for them
- * we'll have 0 offset and 0 size. )
*/
static void __init setup_xstate_features(void)
{
- u32 eax, ebx, ecx, edx, leaf;
-
- xfeatures_nr = fls64(xfeatures_mask);
+ u32 eax, ebx, ecx, edx, i;

- for (leaf = FIRST_EXTENDED_XFEATURE; leaf < xfeatures_nr; leaf++) {
- cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
+ for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
+ cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);

- xstate_offsets[leaf] = ebx;
- xstate_sizes[leaf] = eax;
+ xstate_offsets[i] = ebx;
+ xstate_sizes[i] = eax;

- printk(KERN_INFO "x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n", leaf, ebx, leaf, eax);
+ printk(KERN_INFO "x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n", i, ebx, i, eax);
}
}

@@ -252,7 +244,7 @@ static void __init setup_xstate_comp(voi
xstate_comp_offsets[1] = offsetof(struct fxregs_state, xmm_space);

if (!cpu_has_xsaves) {
- for (i = FIRST_EXTENDED_XFEATURE; i < xfeatures_nr; i++) {
+ for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
xstate_comp_offsets[i] = xstate_offsets[i];
xstate_comp_sizes[i] = xstate_sizes[i];
@@ -264,7 +256,7 @@ static void __init setup_xstate_comp(voi
xstate_comp_offsets[FIRST_EXTENDED_XFEATURE] =
FXSAVE_SIZE + XSAVE_HDR_SIZE;

- for (i = FIRST_EXTENDED_XFEATURE; i < xfeatures_nr; i++) {
+ for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
if (test_bit(i, (unsigned long *)&xfeatures_mask))
xstate_comp_sizes[i] = xstate_sizes[i];
else
_

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