From df7997ab1ca82ae3c37a2f5eb98613fc24527f95 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 26 May 2011 09:48:23 +0200 Subject: [PATCH] [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 +- drivers/s390/block/dasd_diag.c | 4 ++-- drivers/s390/char/sclp.c | 6 +++--- drivers/s390/kvm/kvm_virtio.c | 2 +- 6 files changed, 32 insertions(+), 7 deletions(-) diff --git a/arch/s390/include/asm/s390_ext.h b/arch/s390/include/asm/s390_ext.h index 080876d5f196..85b2154b899f 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 185029919c4d..87b5c532abf1 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 e46ba2927424..6e922b50efa4 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; diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c index 85dddb1e4126..5e8e82db1886 100644 --- a/drivers/s390/block/dasd_diag.c +++ b/drivers/s390/block/dasd_diag.c @@ -642,7 +642,7 @@ dasd_diag_init(void) } ASCEBC(dasd_diag_discipline.ebcname, 4); - ctl_set_bit(0, 9); + service_subclass_irq_register(); register_external_interrupt(0x2603, dasd_ext_handler); dasd_diag_discipline_pointer = &dasd_diag_discipline; return 0; @@ -652,7 +652,7 @@ static void __exit dasd_diag_cleanup(void) { unregister_external_interrupt(0x2603, dasd_ext_handler); - ctl_clear_bit(0, 9); + service_subclass_irq_unregister(); dasd_diag_discipline_pointer = NULL; } diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c index b76c61f82485..b37b98cbbd00 100644 --- a/drivers/s390/char/sclp.c +++ b/drivers/s390/char/sclp.c @@ -885,12 +885,12 @@ sclp_check_interface(void) spin_unlock_irqrestore(&sclp_lock, flags); /* Enable service-signal interruption - needs to happen * with IRQs enabled. */ - ctl_set_bit(0, 9); + service_subclass_irq_register(); /* Wait for signal from interrupt or timeout */ sclp_sync_wait(); /* Disable service-signal interruption - needs to happen * with IRQs enabled. */ - ctl_clear_bit(0,9); + service_subclass_irq_unregister(); spin_lock_irqsave(&sclp_lock, flags); del_timer(&sclp_request_timer); if (sclp_init_req.status == SCLP_REQ_DONE && @@ -1070,7 +1070,7 @@ sclp_init(void) spin_unlock_irqrestore(&sclp_lock, flags); /* Enable service-signal external interruption - needs to happen with * IRQs enabled. */ - ctl_set_bit(0, 9); + service_subclass_irq_register(); sclp_init_mask(1); return 0; diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c index 607998f0b7d8..724b5923b6e2 100644 --- a/drivers/s390/kvm/kvm_virtio.c +++ b/drivers/s390/kvm/kvm_virtio.c @@ -441,7 +441,7 @@ static int __init kvm_devices_init(void) INIT_WORK(&hotplug_work, hotplug_devices); - ctl_set_bit(0, 9); + service_subclass_irq_register(); register_external_interrupt(0x2603, kvm_extint_handler); scan_devices();