Messages in this thread Patch in this message | | | From | Will Deacon <> | Subject | [PATCH 1/2] alpha: irq: run all handlers with interrupts disabled | Date | Sun, 17 Mar 2013 21:49:55 +0000 |
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Linux has expected that interrupt handlers are executed with local interrupts disabled for a while now, so ensure that this is the case on Alpha even for non-device interrupts such as IPIs.
Without this patch, secondary boot results in the following backtrace:
------------[ cut here ]------------ warning: at kernel/softirq.c:139 __local_bh_enable+0xb8/0xd0() modules linked in: fffffc0000867c70 fffffc0000876618 fffffc0000330628 0000000000000200 fffffc000088e1b0 fffffc0000868000 0000000000000000 0000000000000000 fffffc0000331594 fffffc00008c79a0 fffffc000085fac0 0000000000000001 fffffc00003597e0 0000000000000008 fffffc000031b3b4 0000000000000001 0000000000000001 0000000000000000 fffffc0000315c4c fffffc00008b88f8 fffffc0000856e20 fffffc0000856b00 fffffc0001a060c0 0000000000000007 trace: [<fffffc0000330628>] __local_bh_enable+0xb8/0xd0 [<fffffc0000331594>] irq_enter+0x74/0xa0 [<fffffc00003597e0>] scheduler_ipi+0x50/0x100 [<fffffc000031b3b4>] handle_ipi+0x84/0x260 [<fffffc0000315c4c>] do_entint+0x1ac/0x2e0 [<fffffc0000331620>] irq_exit+0x60/0xa0 [<fffffc00003159e8>] handle_irq+0x98/0x100 [<fffffc0000315d68>] do_entint+0x2c8/0x2e0 [<fffffc0000310d80>] ret_from_sys_call+0x0/0x10 [<fffffc0000365124>] load_balance+0x3e4/0x870 [<fffffc0000312bd4>] cpu_idle+0x24/0x80 [<fffffc0000391bd0>] rcu_eqs_enter_common.isra.38+0x0/0x120 [<fffffc0000312bf0>] cpu_idle+0x40/0x80 [<fffffc0000715030>] rest_init+0xc0/0xe0 [<fffffc000031001c>] _stext+0x1c/0x20
---[ end trace 5bbac1dc3a0ec32e ]---
A similar dump occurs if you try to reboot using magic-sysrq.
Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/alpha/kernel/irq.c | 7 ------- arch/alpha/kernel/irq_alpha.c | 9 ++++++++- 2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c index 2872acc..7b2be25 100644 --- a/arch/alpha/kernel/irq.c +++ b/arch/alpha/kernel/irq.c @@ -117,13 +117,6 @@ handle_irq(int irq) return; } - /* - * From here we must proceed with IPL_MAX. Note that we do not - * explicitly enable interrupts afterwards - some MILO PALcode - * (namely LX164 one) seems to have severe problems with RTI - * at IPL 0. - */ - local_irq_disable(); irq_enter(); generic_handle_irq_desc(irq, desc); irq_exit(); diff --git a/arch/alpha/kernel/irq_alpha.c b/arch/alpha/kernel/irq_alpha.c index 772ddfdb..1216dfb 100644 --- a/arch/alpha/kernel/irq_alpha.c +++ b/arch/alpha/kernel/irq_alpha.c @@ -45,6 +45,14 @@ do_entInt(unsigned long type, unsigned long vector, unsigned long la_ptr, struct pt_regs *regs) { struct pt_regs *old_regs; + + /* + * Disable interrupts during IRQ handling. + * Note that there is no matching local_irq_enable() due to + * severe problems with RTI at IPL0 and some MILO PALcode + * (namely LX164). + */ + local_irq_disable(); switch (type) { case 0: #ifdef CONFIG_SMP @@ -62,7 +70,6 @@ do_entInt(unsigned long type, unsigned long vector, { long cpu; - local_irq_disable(); smp_percpu_timer_interrupt(regs); cpu = smp_processor_id(); if (cpu != boot_cpuid) { -- 1.8.0
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