| /* |
| * linux/arch/i386/kernel/irq.c |
| * |
| * 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 <asm/uaccess.h> |
| #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> |
| |
| DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp; |
| EXPORT_PER_CPU_SYMBOL(irq_stat); |
| |
| #ifndef CONFIG_X86_LOCAL_APIC |
| /* |
| * '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("unexpected IRQ trap at vector %02x\n", 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 |
| |
| /* |
| * These should really be __section__(".bss.page_aligned") as well, but |
| * gcc's 3.0 and earlier don't handle that correctly. |
| */ |
| static char softirq_stack[NR_CPUS * THREAD_SIZE] |
| __attribute__((__aligned__(THREAD_SIZE))); |
| |
| static char hardirq_stack[NR_CPUS * THREAD_SIZE] |
| __attribute__((__aligned__(THREAD_SIZE))); |
| |
| /* |
| * 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); |
| } |
| |
| EXPORT_SYMBOL(do_softirq); |
| #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 |
| |