diff options
| author | James Hogan <james.hogan@imgtec.com> | 2013-07-01 13:44:10 +0100 |
|---|---|---|
| committer | James Hogan <james.hogan@imgtec.com> | 2013-07-02 14:12:08 +0100 |
| commit | f6b30d32d242243a967993789c4cf550d840727e (patch) | |
| tree | 95369d42eb77261e5f31b7908ee97af9e2f6a73e /arch/metag/kernel | |
| parent | 9649814432faa9016952895684120942da0d8481 (diff) | |
metag: kick: add missing irq_enter/exit to kick_handler()
kick_handler() doesn't have an irq_enter/exit pair, but it's used for
handling SMP IPIs which require work to be done in softirqs, which are
invoked from irq_exit() when the hard irq nest count reaches 0.
The scheduler_ipi() callback in the IPI handler calls irq_enter/exit
itself, but this is inside kick_handler()'s spin lock critical section,
so if an invoked softirq issues an IPI the kick_handler() will be
re-entered on the same CPU and will deadlock.
This is easily fixed by adding the missing irq_enter/exit to
kick_handler() so that the hard irq nest count doesn't reach 0 until
after the spin lock has been released.
Ideally the spin lock protected handler list will also be replaced by a
lockless RCU protected list since it is certainly mostly read. That can
be done in a later change though.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/metag/kernel')
| -rw-r--r-- | arch/metag/kernel/kick.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/metag/kernel/kick.c b/arch/metag/kernel/kick.c index 50fcbec98cd2..beb377621322 100644 --- a/arch/metag/kernel/kick.c +++ b/arch/metag/kernel/kick.c @@ -26,6 +26,8 @@ * pass it as an argument. */ #include <linux/export.h> +#include <linux/hardirq.h> +#include <linux/irq.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/types.h> @@ -66,6 +68,7 @@ EXPORT_SYMBOL(kick_unregister_func); TBIRES kick_handler(TBIRES State, int SigNum, int Triggers, int Inst, PTBI pTBI) { + struct pt_regs *old_regs; struct kick_irq_handler *kh; struct list_head *lh; int handled = 0; @@ -79,6 +82,9 @@ kick_handler(TBIRES State, int SigNum, int Triggers, int Inst, PTBI pTBI) trace_hardirqs_off(); + old_regs = set_irq_regs((struct pt_regs *)State.Sig.pCtx); + irq_enter(); + /* * There is no need to disable interrupts here because we * can't nest KICK interrupts in a KICK interrupt handler. @@ -97,5 +103,8 @@ kick_handler(TBIRES State, int SigNum, int Triggers, int Inst, PTBI pTBI) WARN_ON(!handled); + irq_exit(); + set_irq_regs(old_regs); + return tail_end(ret); } |