[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20150831222054.94E0616D@viggo.jf.intel.com>
Date: Mon, 31 Aug 2015 15:20:54 -0700
From: Dave Hansen <dave@...1.net>
To: dave@...1.net
Cc: dave.hansen@...ux.intel.com, mingo@...hat.com, x86@...nel.org,
bp@...en8.de, fenghua.yu@...el.com, tim.c.chen@...ux.intel.com,
linux-kernel@...r.kernel.org
Subject: [PATCH 09/15] x86, fpu: add helper xfeature_enabled() instead of test_bit()
From: Dave Hansen <dave.hansen@...ux.intel.com>
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@...ux.intel.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: x86@...nel.org
Cc: Borislav Petkov <bp@...en8.de>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>
Cc: linux-kernel@...r.kernel.org
---
b/arch/x86/kernel/fpu/xstate.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff -puN arch/x86/kernel/fpu/xstate.c~use-xfeature_enabled arch/x86/kernel/fpu/xstate.c
--- a/arch/x86/kernel/fpu/xstate.c~use-xfeature_enabled 2015-08-31 15:17:35.008910377 -0700
+++ b/arch/x86/kernel/fpu/xstate.c 2015-08-31 15:17:35.011910514 -0700
@@ -226,6 +226,16 @@ static void __init print_xstate_features
}
/*
+ * 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(voi
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(voi
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_xst
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;
}
_
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists