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powerpc: Allow emulating optional FPU instructions on CPUs with an FPU

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The e5500 has an FPU, but lacks the optional fsqrt instruction.  This
instruction gets emulated in the kernel, but the emulation uses stale data,
from the last switch out, and does not return the result of the operation
immediately.  Fix both of these conditions by saving and restoring the FPRs
around the emulation point.

MFC after:	1 week
MFC with:	r345829
This commit is contained in:
Justin Hibbits 2019-04-03 04:01:08 +00:00
parent b0fefb25c5
commit 62c7ea1f1d
3 changed files with 10 additions and 5 deletions
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4
sys/powerpc/include/trap.h
View File

@ -152,10 +152,10 @@
#ifndef LOCORE
struct trapframe;
struct pcb;
struct thread;
extern int (*hmi_handler)(struct trapframe *);
void trap(struct trapframe *);
int ppc_instr_emulate(struct trapframe *, struct pcb *);
int ppc_instr_emulate(struct trapframe *, struct thread *);
#endif
#endif /* _POWERPC_TRAP_H_ */

9
sys/powerpc/powerpc/exec_machdep.c
View File

@ -1081,8 +1081,9 @@ emulate_mtspr(int spr, int reg, struct trapframe *frame){
#define XFX 0xFC0007FF
int
ppc_instr_emulate(struct trapframe *frame, struct pcb *pcb)
ppc_instr_emulate(struct trapframe *frame, struct thread *td)
{
struct pcb *pcb;
uint32_t instr;
int reg, sig;
int rs, spr;
@ -1109,12 +1110,16 @@ ppc_instr_emulate(struct trapframe *frame, struct pcb *pcb)
return (0);
}
pcb = td->td_pcb;
#ifdef FPU_EMU
if (!(pcb->pcb_flags & PCB_FPREGS)) {
bzero(&pcb->pcb_fpu, sizeof(pcb->pcb_fpu));
pcb->pcb_flags |= PCB_FPREGS;
}
} else if (pcb->pcb_flags & PCB_FPU)
save_fpu(td);
sig = fpu_emulate(frame, &pcb->pcb_fpu);
if ((sig == 0 || sig == SIGFPE) && pcb->pcb_flags & PCB_FPU)
enable_fpu(td);
#endif
if (sig == SIGILL) {
if (pcb->pcb_lastill != frame->srr0) {

2
sys/powerpc/powerpc/trap.c
View File

@ -363,7 +363,7 @@ trap(struct trapframe *frame)
sig = SIGTRAP;
ucode = TRAP_BRKPT;
} else {
sig = ppc_instr_emulate(frame, td->td_pcb);
sig = ppc_instr_emulate(frame, td);
if (sig == SIGILL) {
if (frame->srr1 & EXC_PGM_PRIV)
ucode = ILL_PRVOPC;