diff options
Diffstat (limited to 'arch/x86/kernel/irq_32.c')
-rw-r--r-- | arch/x86/kernel/irq_32.c | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c new file mode 100644 index 000000000000..e173b763f148 --- /dev/null +++ b/arch/x86/kernel/irq_32.c @@ -0,0 +1,339 @@ +/* + * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar + * + * This file contains the lowest level x86-specific interrupt + * entry, irq-stacks and irq statistics code. All the remaining + * irq logic is done by the generic kernel/irq/ code and + * by the x86-specific irq controller code. (e.g. i8259.c and + * io_apic.c.) + */ + +#include <linux/module.h> +#include <linux/seq_file.h> +#include <linux/interrupt.h> +#include <linux/kernel_stat.h> +#include <linux/notifier.h> +#include <linux/cpu.h> +#include <linux/delay.h> + +#include <asm/apic.h> +#include <asm/uaccess.h> + +DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat); +EXPORT_PER_CPU_SYMBOL(irq_stat); + +DEFINE_PER_CPU(struct pt_regs *, irq_regs); +EXPORT_PER_CPU_SYMBOL(irq_regs); + +/* + * 'what should we do if we get a hw irq event on an illegal vector'. + * each architecture has to answer this themselves. + */ +void ack_bad_irq(unsigned int irq) +{ + printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq); + +#ifdef CONFIG_X86_LOCAL_APIC + /* + * Currently unexpected vectors happen only on SMP and APIC. + * We _must_ ack these because every local APIC has only N + * irq slots per priority level, and a 'hanging, unacked' IRQ + * holds up an irq slot - in excessive cases (when multiple + * unexpected vectors occur) that might lock up the APIC + * completely. + * But only ack when the APIC is enabled -AK + */ + if (cpu_has_apic) + ack_APIC_irq(); +#endif +} + +#ifdef CONFIG_4KSTACKS +/* + * per-CPU IRQ handling contexts (thread information and stack) + */ +union irq_ctx { + struct thread_info tinfo; + u32 stack[THREAD_SIZE/sizeof(u32)]; +}; + +static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly; +static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly; +#endif + +/* + * do_IRQ handles all normal device IRQ's (the special + * SMP cross-CPU interrupts have their own specific + * handlers). + */ +fastcall unsigned int do_IRQ(struct pt_regs *regs) +{ + struct pt_regs *old_regs; + /* high bit used in ret_from_ code */ + int irq = ~regs->orig_eax; + struct irq_desc *desc = irq_desc + irq; +#ifdef CONFIG_4KSTACKS + union irq_ctx *curctx, *irqctx; + u32 *isp; +#endif + + if (unlikely((unsigned)irq >= NR_IRQS)) { + printk(KERN_EMERG "%s: cannot handle IRQ %d\n", + __FUNCTION__, irq); + BUG(); + } + + old_regs = set_irq_regs(regs); + irq_enter(); +#ifdef CONFIG_DEBUG_STACKOVERFLOW + /* Debugging check for stack overflow: is there less than 1KB free? */ + { + long esp; + + __asm__ __volatile__("andl %%esp,%0" : + "=r" (esp) : "0" (THREAD_SIZE - 1)); + if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) { + printk("do_IRQ: stack overflow: %ld\n", + esp - sizeof(struct thread_info)); + dump_stack(); + } + } +#endif + +#ifdef CONFIG_4KSTACKS + + curctx = (union irq_ctx *) current_thread_info(); + irqctx = hardirq_ctx[smp_processor_id()]; + + /* + * this is where we switch to the IRQ stack. However, if we are + * already using the IRQ stack (because we interrupted a hardirq + * handler) we can't do that and just have to keep using the + * current stack (which is the irq stack already after all) + */ + if (curctx != irqctx) { + int arg1, arg2, ebx; + + /* build the stack frame on the IRQ stack */ + isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); + irqctx->tinfo.task = curctx->tinfo.task; + irqctx->tinfo.previous_esp = current_stack_pointer; + + /* + * Copy the softirq bits in preempt_count so that the + * softirq checks work in the hardirq context. + */ + irqctx->tinfo.preempt_count = + (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) | + (curctx->tinfo.preempt_count & SOFTIRQ_MASK); + + asm volatile( + " xchgl %%ebx,%%esp \n" + " call *%%edi \n" + " movl %%ebx,%%esp \n" + : "=a" (arg1), "=d" (arg2), "=b" (ebx) + : "0" (irq), "1" (desc), "2" (isp), + "D" (desc->handle_irq) + : "memory", "cc" + ); + } else +#endif + desc->handle_irq(irq, desc); + + irq_exit(); + set_irq_regs(old_regs); + return 1; +} + +#ifdef CONFIG_4KSTACKS + +static char softirq_stack[NR_CPUS * THREAD_SIZE] + __attribute__((__section__(".bss.page_aligned"))); + +static char hardirq_stack[NR_CPUS * THREAD_SIZE] + __attribute__((__section__(".bss.page_aligned"))); + +/* + * allocate per-cpu stacks for hardirq and for softirq processing + */ +void irq_ctx_init(int cpu) +{ + union irq_ctx *irqctx; + + if (hardirq_ctx[cpu]) + return; + + irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE]; + irqctx->tinfo.task = NULL; + irqctx->tinfo.exec_domain = NULL; + irqctx->tinfo.cpu = cpu; + irqctx->tinfo.preempt_count = HARDIRQ_OFFSET; + irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); + + hardirq_ctx[cpu] = irqctx; + + irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE]; + irqctx->tinfo.task = NULL; + irqctx->tinfo.exec_domain = NULL; + irqctx->tinfo.cpu = cpu; + irqctx->tinfo.preempt_count = 0; + irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); + + softirq_ctx[cpu] = irqctx; + + printk("CPU %u irqstacks, hard=%p soft=%p\n", + cpu,hardirq_ctx[cpu],softirq_ctx[cpu]); +} + +void irq_ctx_exit(int cpu) +{ + hardirq_ctx[cpu] = NULL; +} + +extern asmlinkage void __do_softirq(void); + +asmlinkage void do_softirq(void) +{ + unsigned long flags; + struct thread_info *curctx; + union irq_ctx *irqctx; + u32 *isp; + + if (in_interrupt()) + return; + + local_irq_save(flags); + + if (local_softirq_pending()) { + curctx = current_thread_info(); + irqctx = softirq_ctx[smp_processor_id()]; + irqctx->tinfo.task = curctx->task; + irqctx->tinfo.previous_esp = current_stack_pointer; + + /* build the stack frame on the softirq stack */ + isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); + + asm volatile( + " xchgl %%ebx,%%esp \n" + " call __do_softirq \n" + " movl %%ebx,%%esp \n" + : "=b"(isp) + : "0"(isp) + : "memory", "cc", "edx", "ecx", "eax" + ); + /* + * Shouldnt happen, we returned above if in_interrupt(): + */ + WARN_ON_ONCE(softirq_count()); + } + + local_irq_restore(flags); +} +#endif + +/* + * Interrupt statistics: + */ + +atomic_t irq_err_count; + +/* + * /proc/interrupts printing: + */ + +int show_interrupts(struct seq_file *p, void *v) +{ + int i = *(loff_t *) v, j; + struct irqaction * action; + unsigned long flags; + + if (i == 0) { + seq_printf(p, " "); + for_each_online_cpu(j) + seq_printf(p, "CPU%-8d",j); + seq_putc(p, '\n'); + } + + if (i < NR_IRQS) { + spin_lock_irqsave(&irq_desc[i].lock, flags); + action = irq_desc[i].action; + if (!action) + goto skip; + seq_printf(p, "%3d: ",i); +#ifndef CONFIG_SMP + seq_printf(p, "%10u ", kstat_irqs(i)); +#else + for_each_online_cpu(j) + seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]); +#endif + seq_printf(p, " %8s", irq_desc[i].chip->name); + seq_printf(p, "-%-8s", irq_desc[i].name); + seq_printf(p, " %s", action->name); + + for (action=action->next; action; action = action->next) + seq_printf(p, ", %s", action->name); + + seq_putc(p, '\n'); +skip: + spin_unlock_irqrestore(&irq_desc[i].lock, flags); + } else if (i == NR_IRQS) { + seq_printf(p, "NMI: "); + for_each_online_cpu(j) + seq_printf(p, "%10u ", nmi_count(j)); + seq_putc(p, '\n'); +#ifdef CONFIG_X86_LOCAL_APIC + seq_printf(p, "LOC: "); + for_each_online_cpu(j) + seq_printf(p, "%10u ", + per_cpu(irq_stat,j).apic_timer_irqs); + seq_putc(p, '\n'); +#endif + seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count)); +#if defined(CONFIG_X86_IO_APIC) + seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count)); +#endif + } + return 0; +} + +#ifdef CONFIG_HOTPLUG_CPU +#include <mach_apic.h> + +void fixup_irqs(cpumask_t map) +{ + unsigned int irq; + static int warned; + + for (irq = 0; irq < NR_IRQS; irq++) { + cpumask_t mask; + if (irq == 2) + continue; + + cpus_and(mask, irq_desc[irq].affinity, map); + if (any_online_cpu(mask) == NR_CPUS) { + printk("Breaking affinity for irq %i\n", irq); + mask = map; + } + if (irq_desc[irq].chip->set_affinity) + irq_desc[irq].chip->set_affinity(irq, mask); + else if (irq_desc[irq].action && !(warned++)) + printk("Cannot set affinity for irq %i\n", irq); + } + +#if 0 + barrier(); + /* Ingo Molnar says: "after the IO-APIC masks have been redirected + [note the nop - the interrupt-enable boundary on x86 is two + instructions from sti] - to flush out pending hardirqs and + IPIs. After this point nothing is supposed to reach this CPU." */ + __asm__ __volatile__("sti; nop; cli"); + barrier(); +#else + /* That doesn't seem sufficient. Give it 1ms. */ + local_irq_enable(); + mdelay(1); + local_irq_disable(); +#endif +} +#endif + |