kernel-hacking-2024-linux-steffo/arch/x86_64/kernel/irq.c

/*
 *	linux/arch/x86_64/kernel/irq.c
 *
 *	Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 * This file contains the lowest level x86_64-specific interrupt
 * entry and irq statistics code. All the remaining irq logic is
 * done by the generic kernel/irq/ code and in the
 * x86_64-specific irq controller code. (e.g. i8259.c and
 * io_apic.c.)
 */

#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/io_apic.h>
#include <asm/idle.h>

atomic_t irq_err_count;

#ifdef CONFIG_DEBUG_STACKOVERFLOW
/*
 * Probabilistic stack overflow check:
 *
 * Only check the stack in process context, because everything else
 * runs on the big interrupt stacks. Checking reliably is too expensive,
 * so we just check from interrupts.
 */
static inline void stack_overflow_check(struct pt_regs *regs)
{
	u64 curbase = (u64) current->thread_info;
	static unsigned long warned = -60*HZ;

	if (regs->rsp >= curbase && regs->rsp <= curbase + THREAD_SIZE &&
	    regs->rsp <  curbase + sizeof(struct thread_info) + 128 &&
	    time_after(jiffies, warned + 60*HZ)) {
		printk("do_IRQ: %s near stack overflow (cur:%Lx,rsp:%lx)\n",
		       current->comm, curbase, regs->rsp);
		show_stack(NULL,NULL);
		warned = jiffies;
	}
}
#endif

/*
 * Generic, controller-independent functions:
 */

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, "-%s", handle_irq_name(irq_desc[i].handle_irq));

		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 ", cpu_pda(j)->__nmi_count);
		seq_putc(p, '\n');
		seq_printf(p, "LOC: ");
		for_each_online_cpu(j)
			seq_printf(p, "%10u ", cpu_pda(j)->apic_timer_irqs);
		seq_putc(p, '\n');
		seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
	}
	return 0;
}

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */
asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
{	
	/* high bit used in ret_from_ code  */
	unsigned vector = ~regs->orig_rax;
	unsigned irq;

	exit_idle();
	irq_enter();
	irq = __get_cpu_var(vector_irq)[vector];

	if (unlikely(irq >= NR_IRQS)) {
		printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
					__FUNCTION__, irq);
		BUG();
	}

#ifdef CONFIG_DEBUG_STACKOVERFLOW
	stack_overflow_check(regs);
#endif
	generic_handle_irq(irq, regs);
	irq_exit();

	return 1;
}

#ifdef CONFIG_HOTPLUG_CPU
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);
	}

	/* That doesn't seem sufficient.  Give it 1ms. */
	local_irq_enable();
	mdelay(1);
	local_irq_disable();
}
#endif

extern void call_softirq(void);

asmlinkage void do_softirq(void)
{
 	__u32 pending;
 	unsigned long flags;

 	if (in_interrupt())
 		return;

 	local_irq_save(flags);
 	pending = local_softirq_pending();
 	/* Switch to interrupt stack */
 	if (pending) {
		call_softirq();
		WARN_ON_ONCE(softirq_count());
	}
 	local_irq_restore(flags);
}
EXPORT_SYMBOL(do_softirq);