diff options
Diffstat (limited to 'sys/amd64')
| -rw-r--r-- | sys/amd64/amd64/fpu.c | 34 | ||||
| -rw-r--r-- | sys/amd64/amd64/trap.c | 4 |
2 files changed, 21 insertions, 17 deletions
diff --git a/sys/amd64/amd64/fpu.c b/sys/amd64/amd64/fpu.c index fef47a0..5c61859 100644 --- a/sys/amd64/amd64/fpu.c +++ b/sys/amd64/amd64/fpu.c @@ -362,7 +362,7 @@ fpuexit(struct thread *td) stop_emulating(); fpusave(curpcb->pcb_save); start_emulating(); - PCPU_SET(fpcurthread, 0); + PCPU_SET(fpcurthread, NULL); } critical_exit(); } @@ -603,33 +603,37 @@ fputrap_sse(void) } /* - * Implement device not available (DNA) exception + * Device Not Available (DNA, #NM) exception handler. * - * It would be better to switch FP context here (if curthread != fpcurthread) - * and not necessarily for every context switch, but it is too hard to - * access foreign pcb's. + * It would be better to switch FP context here (if curthread != + * fpcurthread) and not necessarily for every context switch, but it + * is too hard to access foreign pcb's. */ - -static int err_count = 0; - void fpudna(void) { + /* + * This handler is entered with interrupts enabled, so context + * switches may occur before critical_enter() is executed. If + * a context switch occurs, then when we regain control, our + * state will have been completely restored. The CPU may + * change underneath us, but the only part of our context that + * lives in the CPU is CR0.TS and that will be "restored" by + * setting it on the new CPU. + */ critical_enter(); + if (PCPU_GET(fpcurthread) == curthread) { - printf("fpudna: fpcurthread == curthread %d times\n", - ++err_count); + printf("fpudna: fpcurthread == curthread\n"); stop_emulating(); critical_exit(); return; } if (PCPU_GET(fpcurthread) != NULL) { - printf("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n", - PCPU_GET(fpcurthread), - PCPU_GET(fpcurthread)->td_proc->p_pid, - curthread, curthread->td_proc->p_pid); - panic("fpudna"); + panic("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n", + PCPU_GET(fpcurthread), PCPU_GET(fpcurthread)->td_tid, + curthread, curthread->td_tid); } stop_emulating(); /* diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c index a57f42e..a181554 100644 --- a/sys/amd64/amd64/trap.c +++ b/sys/amd64/amd64/trap.c @@ -450,8 +450,8 @@ trap(struct trapframe *frame) case T_XMMFLT: /* SIMD floating-point exception */ case T_FPOPFLT: /* FPU operand fetch fault */ /* - * XXXKIB for now disable any FPU traps in kernel - * handler registration seems to be overkill + * For now, supporting kernel handler + * registration for FPU traps is overkill. */ trap_fatal(frame, 0); goto out; |
