* 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. */
| 796 | * is too hard to access foreign pcb's. |
| 797 | */ |
| 798 | void |
| 799 | fpudna(void) |
| 800 | { |
| 801 | struct thread *td; |
| 802 | |
| 803 | td = curthread; |
| 804 | /* |
| 805 | * This handler is entered with interrupts enabled, so context |
| 806 | * switches may occur before critical_enter() is executed. If |
| 807 | * a context switch occurs, then when we regain control, our |
| 808 | * state will have been completely restored. The CPU may |
| 809 | * change underneath us, but the only part of our context that |
| 810 | * lives in the CPU is CR0.TS and that will be "restored" by |
| 811 | * setting it on the new CPU. |
| 812 | */ |
| 813 | critical_enter(); |
| 814 | |
| 815 | KASSERT((curpcb->pcb_flags & PCB_FPUNOSAVE) == 0, |
| 816 | ("fpudna while in fpu_kern_enter(FPU_KERN_NOCTX)")); |
| 817 | if (__predict_false(PCPU_GET(fpcurthread) == td)) { |
| 818 | /* |
| 819 | * Some virtual machines seems to set %cr0.TS at |
| 820 | * arbitrary moments. Silently clear the TS bit |
| 821 | * regardless of the eager/lazy FPU context switch |
| 822 | * mode. |
| 823 | */ |
| 824 | stop_emulating(); |
| 825 | } else { |
| 826 | if (__predict_false(PCPU_GET(fpcurthread) != NULL)) { |
| 827 | panic( |
| 828 | "fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n", |
| 829 | PCPU_GET(fpcurthread), |
| 830 | PCPU_GET(fpcurthread)->td_tid, td, td->td_tid); |
| 831 | } |
| 832 | restore_fpu_curthread(td); |
| 833 | } |
| 834 | critical_exit(); |
| 835 | } |
| 836 | |
| 837 | void fpu_activate_sw(struct thread *td); /* Called from the context switch */ |
| 838 | void |
no test coverage detected