void
fpurestore(void *addr)
{
if (use_xsave)
xrstor((char *)addr, xsave_mask);
else
fxrstor((char *)addr);
}
void
_thread_machdep_restore_float_state(struct _machdep_state *ms)
{
union savefpu *addr = &ms->fpreg;
if (_thread_machdep_osfxsr()) {
fxrstor(&addr->sv_xmm);
fwait();
} else
frstor(&addr->sv_87);
}
PUBLIC void restore_fpu(struct proc *pr)
{
if(!proc_used_fpu(pr)) {
fninit();
pr->p_misc_flags |= MF_FPU_INITIALIZED;
} else {
if(osfxsr_feature) {
fxrstor(pr->p_fpu_state.fpu_save_area_p);
} else {
frstor(pr->p_fpu_state.fpu_save_area_p);
}
}
}
int restore_fpu(struct proc *pr)
{
int failed;
char *state = pr->p_seg.fpu_state;
assert(state);
if(!proc_used_fpu(pr)) {
fninit();
pr->p_misc_flags |= MF_FPU_INITIALIZED;
} else {
if(osfxsr_feature) {
failed = fxrstor(state);
} else {
failed = frstor(state);
}
if (failed) return EINVAL;
}
return OK;
}
/*
* Implement device not available (DNA) exception
*
* If we were the last lwp to use the FPU, we can simply return.
* Otherwise, we save the previous state, if necessary, and restore
* our last saved state.
*/
void
fpudna(struct cpu_info *ci)
{
uint16_t cw;
uint32_t mxcsr;
struct lwp *l, *fl;
struct pcb *pcb;
int s;
if (ci->ci_fpsaving) {
/* Recursive trap. */
x86_enable_intr();
return;
}
/* Lock out IPIs and disable preemption. */
s = splhigh();
x86_enable_intr();
/* Save state on current CPU. */
l = ci->ci_curlwp;
pcb = lwp_getpcb(l);
fl = ci->ci_fpcurlwp;
if (fl != NULL) {
/*
* It seems we can get here on Xen even if we didn't
* switch lwp. In this case do nothing
*/
if (fl == l) {
KASSERT(pcb->pcb_fpcpu == ci);
clts();
splx(s);
return;
}
KASSERT(fl != l);
fpusave_cpu(true);
KASSERT(ci->ci_fpcurlwp == NULL);
}
/* Save our state if on a remote CPU. */
if (pcb->pcb_fpcpu != NULL) {
/* Explicitly disable preemption before dropping spl. */
KPREEMPT_DISABLE(l);
splx(s);
fpusave_lwp(l, true);
KASSERT(pcb->pcb_fpcpu == NULL);
s = splhigh();
KPREEMPT_ENABLE(l);
}
/*
* Restore state on this CPU, or initialize. Ensure that
* the entire update is atomic with respect to FPU-sync IPIs.
*/
clts();
ci->ci_fpcurlwp = l;
pcb->pcb_fpcpu = ci;
if ((l->l_md.md_flags & MDL_USEDFPU) == 0) {
fninit();
cw = pcb->pcb_savefpu.fp_fxsave.fx_fcw;
fldcw(&cw);
mxcsr = pcb->pcb_savefpu.fp_fxsave.fx_mxcsr;
x86_ldmxcsr(&mxcsr);
l->l_md.md_flags |= MDL_USEDFPU;
} else {
/*
* AMD FPU's do not restore FIP, FDP, and FOP on fxrstor,
* leaking other process's execution history. Clear them
* manually.
*/
static const double zero = 0.0;
int status;
/*
* Clear the ES bit in the x87 status word if it is currently
* set, in order to avoid causing a fault in the upcoming load.
*/
fnstsw(&status);
if (status & 0x80)
fnclex();
/*
* Load the dummy variable into the x87 stack. This mangles
* the x87 stack, but we don't care since we're about to call
* fxrstor() anyway.
*/
fldummy(&zero);
fxrstor(&pcb->pcb_savefpu);
}
KASSERT(ci == curcpu());
splx(s);
}