[Bug-fix for "[BUG?][2.6.25-mm1] sleeping during IRQ disabled"]
This patch does:
- enable interrupts before calling schedule() as same as others, ex. x86
- enable interrupts during ia64_do_signal() and ia64_sync_krbs()
- do_notify_resume_user() is still called with interrupts disabled, since
we can take short path of fsys_mode if-statement quickly.
- pfm_handle_work() is also called with interrupts disabled, since
it can deal interrupt mask within itself.
- fix/add some comments/notes
Reported-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
---
arch/ia64/kernel/entry.S | 14 ++++++++++----
arch/ia64/kernel/process.c | 25 +++++++++++++++++++++----
2 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index e49ad8c..ef6b031 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1156,6 +1156,9 @@ skip_rbs_switch:
* r31 = current->thread_info->flags
* On exit:
* p6 = TRUE if work-pending-check needs to be redone
+ *
+ * Interrupts are disabled on entry, reenabled depend on work, and
+ * disabled on exit.
*/
.work_pending_syscall:
add r2=-8,r2
@@ -1170,8 +1173,8 @@ skip_rbs_switch:
(pKStk) dep r21=-1,r0,PREEMPT_ACTIVE_BIT,1
;;
(pKStk) st4 [r20]=r21
- ssm psr.i // enable interrupts
#endif
+ ssm psr.i // enable interrupts
br.call.spnt.many rp=schedule
.ret9: cmp.eq p6,p0=r0,r0 // p6 <- 1
rsm psr.i // disable interrupts
@@ -1234,9 +1237,12 @@ GLOBAL_ENTRY(ia64_invoke_schedule_tail)
END(ia64_invoke_schedule_tail)
/*
- * Setup stack and call do_notify_resume_user(). Note that pSys and pNonSys need to
- * be set up by the caller. We declare 8 input registers so the system call
- * args get preserved, in case we need to restart a system call.
+ * Setup stack and call do_notify_resume_user(), keeping interrupts
+ * disabled.
+ *
+ * Note that pSys and pNonSys need to be set up by the caller.
+ * We declare 8 input registers so the system call args get preserved,
+ * in case we need to restart a system call.
*/
ENTRY(notify_resume_user)
.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 58dcfac..a3a34b4 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -167,11 +167,18 @@ void tsk_clear_notify_resume(struct task_struct *tsk)
clear_ti_thread_flag(task_thread_info(tsk), TIF_NOTIFY_RESUME);
}
+/*
+ * do_notify_resume_user():
+ * Called from notify_resume_user at entry.S, with interrupts disabled.
+ */
void
-do_notify_resume_user (sigset_t *unused, struct sigscratch *scr, long in_syscall)
+do_notify_resume_user(sigset_t *unused, struct sigscratch *scr, long in_syscall)
{
if (fsys_mode(current, &scr->pt)) {
- /* defer signal-handling etc. until we return to privilege-level 0. */
+ /*
+ * defer signal-handling etc. until we return to
+ * privilege-level 0.
+ */
if (!ia64_psr(&scr->pt)->lp)
ia64_psr(&scr->pt)->lp = 1;
return;
@@ -179,16 +186,26 @@ do_notify_resume_user (sigset_t *unused, struct sigscratch *scr, long in_syscall
#ifdef CONFIG_PERFMON
if (current->thread.pfm_needs_checking)
+ /*
+ * Note: pfm_handle_work() allow us to call it with interrupts
+ * disabled, and may enable interrupts within the function.
+ */
pfm_handle_work();
#endif
/* deal with pending signal delivery */
- if (test_thread_flag(TIF_SIGPENDING))
+ if (test_thread_flag(TIF_SIGPENDING)) {
+ local_irq_enable(); /* force interrupt enable */
ia64_do_signal(scr, in_syscall);
+ }
/* copy user rbs to kernel rbs */
- if (unlikely(test_thread_flag(TIF_RESTORE_RSE)))
+ if (unlikely(test_thread_flag(TIF_RESTORE_RSE))) {
+ local_irq_enable(); /* force interrupt enable */
ia64_sync_krbs();
+ }
+
+ local_irq_disable(); /* force interrupt disable */
}
static int pal_halt = 1;
--
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