From df7997ab1ca82ae3c37a2f5eb98613fc24527f95 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 26 May 2011 09:48:23 +0200 Subject: [S390] irq: fix service signal external interrupt handling Interrupt sources like pfault, sclp, dasd_diag and virtio all use the service signal external interrupt subclass mask in control register 0 to enable and disable the corresponding interrupt. Because no reference counting is implemented each subsystem thinks it is the only user of subclass and sets and clears the bit like it wants. This leads to case that unloading the dasd diag module under z/VM causes both sclp and pfault interrupts to be masked. The result will be locked up system sooner or later. Fix this by introducing a new way to set (register) and clear (unregister) the service signal subclass mask bit in cr0. Also convert all drivers. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/s390_ext.h | 2 ++ arch/s390/kernel/s390_ext.c | 23 +++++++++++++++++++++++ arch/s390/mm/fault.c | 2 +- 3 files changed, 26 insertions(+), 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/include/asm/s390_ext.h b/arch/s390/include/asm/s390_ext.h index 080876d5f19..85b2154b899 100644 --- a/arch/s390/include/asm/s390_ext.h +++ b/arch/s390/include/asm/s390_ext.h @@ -13,5 +13,7 @@ typedef void (*ext_int_handler_t)(unsigned int, unsigned int, unsigned long); int register_external_interrupt(__u16 code, ext_int_handler_t handler); int unregister_external_interrupt(__u16 code, ext_int_handler_t handler); +void service_subclass_irq_register(void); +void service_subclass_irq_unregister(void); #endif /* _S390_EXTINT_H */ diff --git a/arch/s390/kernel/s390_ext.c b/arch/s390/kernel/s390_ext.c index 185029919c4..87b5c532abf 100644 --- a/arch/s390/kernel/s390_ext.c +++ b/arch/s390/kernel/s390_ext.c @@ -106,3 +106,26 @@ void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code, irq_exit(); set_irq_regs(old_regs); } + +static DEFINE_SPINLOCK(sc_irq_lock); +static int sc_irq_refcount; + +void service_subclass_irq_register(void) +{ + spin_lock(&sc_irq_lock); + if (!sc_irq_refcount) + ctl_set_bit(0, 9); + sc_irq_refcount++; + spin_unlock(&sc_irq_lock); +} +EXPORT_SYMBOL(service_subclass_irq_register); + +void service_subclass_irq_unregister(void) +{ + spin_lock(&sc_irq_lock); + sc_irq_refcount--; + if (!sc_irq_refcount) + ctl_clear_bit(0, 9); + spin_unlock(&sc_irq_lock); +} +EXPORT_SYMBOL(service_subclass_irq_unregister); diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index e46ba292742..6e922b50efa 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -613,7 +613,7 @@ static int __init pfault_irq_init(void) rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; if (rc) goto out_pfault; - ctl_set_bit(0, 9); + service_subclass_irq_register(); hotcpu_notifier(pfault_cpu_notify, 0); return 0; -- cgit v1.2.3-18-g5258