diff options
Diffstat (limited to 'sys/i386/i386/vm_machdep.c')
| -rw-r--r-- | sys/i386/i386/vm_machdep.c | 59 |
1 files changed, 42 insertions, 17 deletions
diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c index 502de6e7f38f..471128e1713d 100644 --- a/sys/i386/i386/vm_machdep.c +++ b/sys/i386/i386/vm_machdep.c @@ -167,13 +167,15 @@ cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) return; } - /* Ensure that td1's pcb is up to date. */ - if (td1 == curthread) + /* Ensure that td1's pcb is up to date for user processes. */ + if ((td2->td_pflags & TDP_KTHREAD) == 0) { + MPASS(td1 == curthread); td1->td_pcb->pcb_gs = rgs(); - critical_enter(); - if (PCPU_GET(fpcurthread) == td1) - npxsave(td1->td_pcb->pcb_save); - critical_exit(); + critical_enter(); + if (PCPU_GET(fpcurthread) == td1) + npxsave(td1->td_pcb->pcb_save); + critical_exit(); + } /* Point the pcb to the top of the stack */ pcb2 = get_pcb_td(td2); @@ -184,8 +186,19 @@ cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) /* Properly initialize pcb_save */ pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); - bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2), - cpu_max_ext_state_size); + + /* Kernel processes start with clean NPX and segment bases. */ + if ((td2->td_pflags & TDP_KTHREAD) != 0) { + pcb2->pcb_gs = _udatasel; + set_fsbase(td2, 0); + set_gsbase(td2, 0); + pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE | + PCB_KERNNPX | PCB_KERNNPX_THR); + } else { + MPASS((pcb2->pcb_flags & (PCB_KERNNPX | PCB_KERNNPX_THR)) == 0); + bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2), + cpu_max_ext_state_size); + } /* Point mdproc and then copy over td1's contents */ mdp2 = &p2->p_md; @@ -428,13 +441,15 @@ cpu_copy_thread(struct thread *td, struct thread *td0) /* Point the pcb to the top of the stack. */ pcb2 = td->td_pcb; - /* Ensure that td0's pcb is up to date. */ - if (td0 == curthread) + /* Ensure that td0's pcb is up to date for user threads. */ + if ((td->td_pflags & TDP_KTHREAD) == 0) { + MPASS(td0 == curthread); td0->td_pcb->pcb_gs = rgs(); - critical_enter(); - if (PCPU_GET(fpcurthread) == td0) - npxsave(td0->td_pcb->pcb_save); - critical_exit(); + critical_enter(); + if (PCPU_GET(fpcurthread) == td0) + npxsave(td0->td_pcb->pcb_save); + critical_exit(); + } /* * Copy the upcall pcb. This loads kernel regs. @@ -442,10 +457,20 @@ cpu_copy_thread(struct thread *td, struct thread *td0) * values here. */ bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); - pcb2->pcb_flags &= ~PCB_KERNNPX; pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); - bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save, - cpu_max_ext_state_size); + + /* Kernel threads start with clean NPX and segment bases. */ + if ((td->td_pflags & TDP_KTHREAD) != 0) { + pcb2->pcb_gs = _udatasel; + set_fsbase(td, 0); + set_gsbase(td, 0); + pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE | + PCB_KERNNPX | PCB_KERNNPX_THR); + } else { + MPASS((pcb2->pcb_flags & (PCB_KERNNPX | PCB_KERNNPX_THR)) == 0); + bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save, + cpu_max_ext_state_size); + } /* * Create a new fresh stack for the new thread. |