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authorDave Hansen <dave.hansen@linux.intel.com>2015-09-02 16:31:29 -0700
committerIngo Molnar <mingo@kernel.org>2015-09-14 12:21:59 +0200
commit633d54c47a5bedfb42f10e6a63eeeebd35abdb4c (patch)
tree45237ce470657344893177c898ef7e9b831c6d7c /arch/x86/kernel/fpu
parentee9ae257eb17d3426ee9ab91449a3aa443298b36 (diff)
x86/fpu: Add xfeature_enabled() helper instead of test_bit()
We currently use test_bit() in a few places to see if an xfeature is enabled. It ends up being a bit ugly because 'xfeatures_mask' is a u64 and test_bit wants an 'unsigned long' so it requires a cast. The *_bit() functions are also techincally atomic, which we have no need for here. So, remove the test_bit()s and replace with the new xfeature_enabled() helper. This also provides a central place to add a comment about the future need to support 'system xstates'. 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/20150902233129.B1534F86@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/fpu')
-rw-r--r--arch/x86/kernel/fpu/xstate.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 61ec60bcbb63..ba6b6e0baf88 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -226,6 +226,16 @@ static void __init print_xstate_features(void)
}
/*
+ * Note that in the future we will likely need a pair of
+ * functions here: one for user xstates and the other for
+ * system xstates. For now, they are the same.
+ */
+static int xfeature_enabled(enum xfeature xfeature)
+{
+ return !!(xfeatures_mask & (1UL << xfeature));
+}
+
+/*
* This function sets up offsets and sizes of all extended states in
* xsave area. This supports both standard format and compacted format
* of the xsave aread.
@@ -245,7 +255,7 @@ static void __init setup_xstate_comp(void)
if (!cpu_has_xsaves) {
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
- if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
+ if (xfeature_enabled(i)) {
xstate_comp_offsets[i] = xstate_offsets[i];
xstate_comp_sizes[i] = xstate_sizes[i];
}
@@ -257,7 +267,7 @@ static void __init setup_xstate_comp(void)
FXSAVE_SIZE + XSAVE_HDR_SIZE;
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
- if (test_bit(i, (unsigned long *)&xfeatures_mask))
+ if (xfeature_enabled(i))
xstate_comp_sizes[i] = xstate_sizes[i];
else
xstate_comp_sizes[i] = 0;
@@ -319,7 +329,7 @@ static unsigned int __init calculate_xstate_size(void)
calculated_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
for (i = FIRST_EXTENDED_XFEATURE; i < 64; i++) {
- if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
+ if (xfeature_enabled(i)) {
cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
calculated_xstate_size += eax;
}