df7997ab1c
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 <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
131 lines
3 KiB
C
131 lines
3 KiB
C
/*
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* Copyright IBM Corp. 1999,2010
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* Author(s): Holger Smolinski <Holger.Smolinski@de.ibm.com>,
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* Martin Schwidefsky <schwidefsky@de.ibm.com>,
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*/
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#include <linux/kernel_stat.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/ftrace.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <asm/s390_ext.h>
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#include <asm/irq_regs.h>
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#include <asm/cputime.h>
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#include <asm/lowcore.h>
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#include <asm/irq.h>
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#include "entry.h"
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struct ext_int_info {
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struct ext_int_info *next;
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ext_int_handler_t handler;
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__u16 code;
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};
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/*
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* ext_int_hash[index] is the start of the list for all external interrupts
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* that hash to this index. With the current set of external interrupts
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* (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
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* iucv and 0x2603 pfault) this is always the first element.
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*/
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static struct ext_int_info *ext_int_hash[256];
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static inline int ext_hash(__u16 code)
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{
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return (code + (code >> 9)) & 0xff;
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}
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int register_external_interrupt(__u16 code, ext_int_handler_t handler)
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{
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struct ext_int_info *p;
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int index;
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p = kmalloc(sizeof(*p), GFP_ATOMIC);
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if (!p)
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return -ENOMEM;
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p->code = code;
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p->handler = handler;
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index = ext_hash(code);
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p->next = ext_int_hash[index];
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ext_int_hash[index] = p;
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return 0;
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}
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EXPORT_SYMBOL(register_external_interrupt);
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int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
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{
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struct ext_int_info *p, *q;
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int index;
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index = ext_hash(code);
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q = NULL;
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p = ext_int_hash[index];
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while (p) {
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if (p->code == code && p->handler == handler)
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break;
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q = p;
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p = p->next;
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}
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if (!p)
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return -ENOENT;
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if (q)
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q->next = p->next;
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else
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ext_int_hash[index] = p->next;
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kfree(p);
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return 0;
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}
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EXPORT_SYMBOL(unregister_external_interrupt);
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void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
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unsigned int param32, unsigned long param64)
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{
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struct pt_regs *old_regs;
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unsigned short code;
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struct ext_int_info *p;
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int index;
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code = (unsigned short) ext_int_code;
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old_regs = set_irq_regs(regs);
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s390_idle_check(regs, S390_lowcore.int_clock,
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S390_lowcore.async_enter_timer);
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irq_enter();
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if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
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/* Serve timer interrupts first. */
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clock_comparator_work();
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kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
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if (code != 0x1004)
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__get_cpu_var(s390_idle).nohz_delay = 1;
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index = ext_hash(code);
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for (p = ext_int_hash[index]; p; p = p->next) {
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if (likely(p->code == code))
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p->handler(ext_int_code, param32, param64);
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}
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irq_exit();
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set_irq_regs(old_regs);
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}
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static DEFINE_SPINLOCK(sc_irq_lock);
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static int sc_irq_refcount;
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void service_subclass_irq_register(void)
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{
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spin_lock(&sc_irq_lock);
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if (!sc_irq_refcount)
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ctl_set_bit(0, 9);
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sc_irq_refcount++;
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spin_unlock(&sc_irq_lock);
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}
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EXPORT_SYMBOL(service_subclass_irq_register);
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void service_subclass_irq_unregister(void)
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{
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spin_lock(&sc_irq_lock);
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sc_irq_refcount--;
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if (!sc_irq_refcount)
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ctl_clear_bit(0, 9);
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spin_unlock(&sc_irq_lock);
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}
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EXPORT_SYMBOL(service_subclass_irq_unregister);
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