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.sid...@intel.com>
---
Documentation/kernel-parameters.txt | 4 +++-
arch/x86/kernel/xsave.c | 17 ++++++++++++-----
2 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index b21bcbd..e0edd14 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1835,8 +1835,10 @@ bytes respectively. Such letter suffixes can also be
entirely omitted.
enabling legacy floating-point and sse state.
eagerfpu= [X86]
- on enable eager fpu restore (default for xsaveopt)
+ on enable eager fpu restore
off disable eager fpu restore
+ auto selects the default scheme, which automatically
+ enables eagerfpu restore for xsaveopt.
nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
wfi(ARM) instruction doesn't work correctly and not to
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index a447a7c..f9dfaba 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -507,13 +507,15 @@ 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);
@@ -556,8 +558,9 @@ 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);
@@ -597,6 +600,10 @@ 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;
--
1.7.6.5
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