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Commit 3633c730 authored by Hidetoshi Seto's avatar Hidetoshi Seto Committed by Tony Luck
Browse files

[IA64] fix interrupt masking for pending works on kernel leave 



[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: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent f13ae30e

arch/ia64/kernel/entry.S

+10 −4
Original line number Diff line number Diff line
@@ -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)

arch/ia64/kernel/process.c

+21 −4
Original line number Diff line number Diff line
@@ -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)

{

	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;
@@ -179,18 +186,28 @@ 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;

static int can_do_pal_halt = 1;