diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index b8624d53c379..228cf0b295db 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -124,7 +124,7 @@ struct _lowcore {
/* Address space pointer. */
__u32 kernel_asce; /* 0x02ac */
__u32 user_asce; /* 0x02b0 */
- __u8 pad_0x02b4[0x02b8-0x02b4]; /* 0x02b4 */
+ __u32 current_pid; /* 0x02b4 */
/* SMP info area */
__u32 cpu_nr; /* 0x02b8 */
@@ -255,7 +255,7 @@ struct _lowcore {
/* Address space pointer. */
__u64 kernel_asce; /* 0x0310 */
__u64 user_asce; /* 0x0318 */
- __u8 pad_0x0320[0x0328-0x0320]; /* 0x0320 */
+ __u64 current_pid; /* 0x0320 */
/* SMP info area */
__u32 cpu_nr; /* 0x0328 */
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 2c79b6416271..1300c3025334 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -84,6 +84,7 @@ struct thread_struct {
struct per_event per_event; /* Cause of the last PER trap */
/* pfault_wait is used to block the process on a pfault event */
unsigned long pfault_wait;
+ struct list_head list;
};
typedef struct thread_struct thread_struct;
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index ef4555611013..edfbd17d7082 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -124,6 +124,7 @@ int main(void)
DEFINE(__LC_LAST_UPDATE_TIMER, offsetof(struct _lowcore, last_update_timer));
DEFINE(__LC_LAST_UPDATE_CLOCK, offsetof(struct _lowcore, last_update_clock));
DEFINE(__LC_CURRENT, offsetof(struct _lowcore, current_task));
+ DEFINE(__LC_CURRENT_PID, offsetof(struct _lowcore, current_pid));
DEFINE(__LC_THREAD_INFO, offsetof(struct _lowcore, thread_info));
DEFINE(__LC_KERNEL_STACK, offsetof(struct _lowcore, kernel_stack));
DEFINE(__LC_ASYNC_STACK, offsetof(struct _lowcore, async_stack));
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 1b67fc6ebdc2..0476174dfff5 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -212,6 +212,7 @@ __switch_to:
lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4
lm %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
st %r3,__LC_CURRENT # store task struct of next
+ mvc __LC_CURRENT_PID(4,%r0),__TASK_pid(%r3) # store pid of next
st %r5,__LC_THREAD_INFO # store thread info of next
ahi %r5,STACK_SIZE # end of kernel stack of next
st %r5,__LC_KERNEL_STACK # store end of kernel stack
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 9fd864563499..d61967e2eab0 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -220,6 +220,7 @@ __switch_to:
lctl %c4,%c4,__TASK_pid(%r3) # load pid to control reg. 4
lmg %r6,%r15,__SF_GPRS(%r15) # load gprs of next task
stg %r3,__LC_CURRENT # store task struct of next
+ mvc __LC_CURRENT_PID+4(4,%r0),__TASK_pid(%r3) # store pid of next
stg %r5,__LC_THREAD_INFO # store thread info of next
aghi %r5,STACK_SIZE # end of kernel stack of next
stg %r5,__LC_KERNEL_STACK # store end of kernel stack
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 177745c520ca..1ca656478326 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -466,7 +466,7 @@ typedef struct {
int pfault_init(void)
{
pfault_refbk_t refbk =
- { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48,
+ { 0x258, 0, 5, 2, __LC_CURRENT_PID, 1ULL << 48, 1ULL << 48,
__PF_RES_FIELD };
int rc;
@@ -498,11 +498,15 @@ void pfault_fini(void)
: : "a" (&refbk), "m" (refbk) : "cc");
}
+static DEFINE_SPINLOCK(pfault_lock);
+static LIST_HEAD(pfault_list);
+
static void pfault_interrupt(unsigned int ext_int_code,
unsigned int param32, unsigned long param64)
{
struct task_struct *tsk;
__u16 subcode;
+ pid_t pid;
/*
* Get the external interruption subcode & pfault
@@ -514,44 +518,79 @@ static void pfault_interrupt(unsigned int ext_int_code,
if ((subcode & 0xff00) != __SUBCODE_MASK)
return;
kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++;
-
- /*
- * Get the token (= address of the task structure of the affected task).
- */
-#ifdef CONFIG_64BIT
- tsk = (struct task_struct *) param64;
-#else
- tsk = (struct task_struct *) param32;
-#endif
-
+ if (subcode & 0x0080) {
+ /* Get the token (= pid of the affected task). */
+ pid = sizeof(void *) == 4 ? param32 : param64;
+ rcu_read_lock();
+ tsk = find_task_by_pid_ns(pid, &init_pid_ns);
+ if (tsk)
+ get_task_struct(tsk);
+ rcu_read_unlock();
+ if (!tsk)
+ return;
+ } else {
+ tsk = current;
+ }
+ spin_lock(&pfault_lock);
if (subcode & 0x0080) {
/* signal bit is set -> a page has been swapped in by VM */
- if (xchg(&tsk->thread.pfault_wait, -1) != 0) {
+ if (tsk->thread.pfault_wait == 1) {
/* Initial interrupt was faster than the completion
* interrupt. pfault_wait is valid. Set pfault_wait
* back to zero and wake up the process. This can
* safely be done because the task is still sleeping
* and can't produce new pfaults. */
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
+ * interrupt doesn't put the task to sleep. */
+ tsk->thread.pfault_wait = -1;
}
+ put_task_struct(tsk);
} else {
/* signal bit not set -> a real page is missing. */
- get_task_struct(tsk);
- set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- if (xchg(&tsk->thread.pfault_wait, 1) != 0) {
+ if (tsk->thread.pfault_wait == -1) {
/* Completion interrupt was faster than the initial
- * interrupt (swapped in a -1 for pfault_wait). Set
- * pfault_wait back to zero and exit. This can be
- * done safely because tsk is running in kernel
- * mode and can't produce new pfaults. */
+ * interrupt (pfault_wait == -1). Set pfault_wait
+ * back to zero and exit. */
tsk->thread.pfault_wait = 0;
- set_task_state(tsk, TASK_RUNNING);
- put_task_struct(tsk);
- } else
+ } else {
+ /* Initial interrupt arrived before completion
+ * interrupt. Let the task sleep. */
+ tsk->thread.pfault_wait = 1;
+ list_add(&tsk->thread.list, &pfault_list);
+ set_task_state(tsk, TASK_UNINTERRUPTIBLE);
set_tsk_need_resched(tsk);
+ }
}
+ spin_unlock(&pfault_lock);
+}
+
+static int __cpuinit pfault_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ struct thread_struct *thread, *next;
+ struct task_struct *tsk;
+
+ switch (action) {
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ spin_lock_irq(&pfault_lock);
+ list_for_each_entry_safe(thread, next, &pfault_list, list) {
+ thread->pfault_wait = 0;
+ list_del(&thread->list);
+ tsk = container_of(thread, struct task_struct, thread);
+ wake_up_process(tsk);
+ }
+ spin_unlock_irq(&pfault_lock);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
}
static int __init pfault_irq_init(void)
@@ -568,8 +607,10 @@ static int __init pfault_irq_init(void)
pfault_disable = 1;
return rc;
}
- if (pfault_init() == 0)
+ if (pfault_init() == 0) {
+ hotcpu_notifier(pfault_cpu_notify, 0);
return 0;
+ }
/* Tough luck, no pfault. */
pfault_disable = 1;