On Thu, Mar 10, 2016 at 03:31:43PM +0200, Andy Shevchenko wrote:
> Looks like it lacks that one.
>
> # grep -i fxsr /proc/cpuinfo; echo $?
> 1
Ok, so looking at where the warning comes from:
[ 14.714533] WARNING: CPU: 0 PID: 823 at
arch/x86/include/asm/fpu/internal.h:163 fpu__clear+0x8c/0x160
static inline void copy_kernel_to_fxregs(struct fxregs_state *fx)
{
int err;
if (config_enabled(CONFIG_X86_32)) {
err = check_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
^^^^^^^^^^^^^^^^^
} else {
...
/* Copying from a kernel buffer to FPU registers should never fail: */
WARN_ON_FPU(err);
and the stacktrace is pretty clear:
flush_thread
|-> fpu__clear(&tsk->thread.fpu);
|-> we are eager by default here:
if (!use_eager_fpu() || !static_cpu_has(X86_FEATURE_FPU)) {
/* FPU state will be reallocated lazily at the first use. */
fpu__drop(fpu);
} else {
--> we're in that branch.
copy_init_fpstate_to_fpregs();
|-> copy_kernel_to_fxregs()
I think we should use FRSTOR on quark, i.e., copy_kernel_to_fregs().
Does this untested wild guess even work?
---
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index dea8e76d60c6..bbafe5e8a1a6 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -474,8 +474,11 @@ static inline void copy_init_fpstate_to_fpregs(void)
{
if (use_xsave())
copy_kernel_to_xregs(&init_fpstate.xsave, -1);
- else
+ else if (static_cpu_has(X86_FEATURE_FXSR))
copy_kernel_to_fxregs(&init_fpstate.fxsave);
+ else
+ copy_kernel_to_fregs(&init_fpstate.fsave);
+
}
/*
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
