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authorSuresh Siddha <suresh.b.siddha@intel.com>2012-09-10 19:32:32 +0200
committerH. Peter Anvin <hpa@linux.intel.com>2012-09-19 00:52:24 +0200
commite00229819f306b1f86134095347e9187dc346bd1 (patch)
tree58184b30fb2dca0f14c0b2cdc60b958529154893 /arch/x86
parentx86, fpu: enable eagerfpu by default for xsaveopt (diff)
downloadlinux-e00229819f306b1f86134095347e9187dc346bd1.tar.xz
linux-e00229819f306b1f86134095347e9187dc346bd1.zip
x86, fpu: make eagerfpu= boot param tri-state
Add the "eagerfpu=auto" (that selects the default scheme in enabling eagerfpu) which can override compiled-in boot parameters like "eagerfpu=on/off" (that force enable/disable eagerfpu). Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Link: http://lkml.kernel.org/r/1347300665-6209-5-git-send-email-suresh.b.siddha@intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/xsave.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index e99f75439f6d..4e89b3dd408d 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -508,13 +508,15 @@ static void __init setup_init_fpu_buf(void)
xsave_state(init_xstate_buf, -1);
}
-static int disable_eagerfpu;
+static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
static int __init eager_fpu_setup(char *s)
{
if (!strcmp(s, "on"))
- setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
+ eagerfpu = ENABLE;
else if (!strcmp(s, "off"))
- disable_eagerfpu = 1;
+ eagerfpu = DISABLE;
+ else if (!strcmp(s, "auto"))
+ eagerfpu = AUTO;
return 1;
}
__setup("eagerfpu=", eager_fpu_setup);
@@ -557,8 +559,9 @@ static void __init xstate_enable_boot_cpu(void)
prepare_fx_sw_frame();
setup_init_fpu_buf();
- if (cpu_has_xsaveopt && !disable_eagerfpu)
- setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
+ /* Auto enable eagerfpu for xsaveopt */
+ if (cpu_has_xsaveopt && eagerfpu != DISABLE)
+ eagerfpu = ENABLE;
pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n",
pcntxt_mask, xstate_size);
@@ -598,6 +601,10 @@ void __cpuinit eager_fpu_init(void)
clear_used_math();
current_thread_info()->status = 0;
+
+ if (eagerfpu == ENABLE)
+ setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
+
if (!cpu_has_eager_fpu) {
stts();
return;