diff options
Diffstat (limited to 'arch/s390/mm/fault.c')
| -rw-r--r-- | arch/s390/mm/fault.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 46ef3fd0663b..f2b11ee3fb3a 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -443,6 +443,7 @@ int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) struct pt_regs regs; int access, fault; + /* Emulate a uaccess fault from kernel mode. */ regs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK; if (!irqs_disabled()) regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; @@ -452,12 +453,12 @@ int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) regs.int_parm_long = (uaddr & PAGE_MASK) | 2; access = write ? VM_WRITE : VM_READ; fault = do_exception(®s, access); - if (unlikely(fault)) { - if (fault & VM_FAULT_OOM) - return -EFAULT; - else if (fault & VM_FAULT_SIGBUS) - do_sigbus(®s); - } + /* + * Since the fault happened in kernel mode while performing a uaccess + * all we need to do now is emulating a fixup in case "fault" is not + * zero. + * For the calling uaccess functions this results always in -EFAULT. + */ return fault ? -EFAULT : 0; } @@ -574,6 +575,7 @@ static void pfault_interrupt(struct ext_code ext_code, tsk->thread.pfault_wait = 0; list_del(&tsk->thread.list); wake_up_process(tsk); + put_task_struct(tsk); } else { /* Completion interrupt was faster than initial * interrupt. Set pfault_wait to -1 so the initial @@ -588,14 +590,22 @@ static void pfault_interrupt(struct ext_code ext_code, put_task_struct(tsk); } else { /* signal bit not set -> a real page is missing. */ - if (tsk->thread.pfault_wait == -1) { + if (tsk->thread.pfault_wait == 1) { + /* Already on the list with a reference: put to sleep */ + set_task_state(tsk, TASK_UNINTERRUPTIBLE); + set_tsk_need_resched(tsk); + } else if (tsk->thread.pfault_wait == -1) { /* Completion interrupt was faster than the initial * interrupt (pfault_wait == -1). Set pfault_wait * back to zero and exit. */ tsk->thread.pfault_wait = 0; } else { /* Initial interrupt arrived before completion - * interrupt. Let the task sleep. */ + * interrupt. Let the task sleep. + * An extra task reference is needed since a different + * cpu may set the task state to TASK_RUNNING again + * before the scheduler is reached. */ + get_task_struct(tsk); tsk->thread.pfault_wait = 1; list_add(&tsk->thread.list, &pfault_list); set_task_state(tsk, TASK_UNINTERRUPTIBLE); @@ -620,6 +630,7 @@ static int __cpuinit pfault_cpu_notify(struct notifier_block *self, list_del(&thread->list); tsk = container_of(thread, struct task_struct, thread); wake_up_process(tsk); + put_task_struct(tsk); } spin_unlock_irq(&pfault_lock); break; |