[mirror_ubuntu-zesty-kernel.git] / arch / x86 / kernel / irq_64.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 <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/smp.h>
#include <asm/io_apic.h>
#include <asm/idle.h>
#include <asm/apic.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);

int sysctl_panic_on_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)
{
#ifdef CONFIG_DEBUG_STACKOVERFLOW
	struct orig_ist *oist;
	u64 irq_stack_top, irq_stack_bottom;
	u64 estack_top, estack_bottom;
	u64 curbase = (u64)task_stack_page(current);

	if (user_mode_vm(regs))
		return;

	if (regs->sp >= curbase + sizeof(struct thread_info) +
				  sizeof(struct pt_regs) + 128 &&
	    regs->sp <= curbase + THREAD_SIZE)
		return;

	irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack);
	irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
		return;

	oist = &__get_cpu_var(orig_ist);
	estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ;
	estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
		return;

	WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n",
		current->comm, curbase, regs->sp,
		irq_stack_top, irq_stack_bottom,
		estack_top, estack_bottom);

	if (sysctl_panic_on_stackoverflow)
		panic("low stack detected by irq handler - check messages\n");
#endif
}

bool handle_irq(unsigned irq, struct pt_regs *regs)
{
	struct irq_desc *desc;

	stack_overflow_check(regs);

	desc = irq_to_desc(irq);
	if (unlikely(!desc))
		return false;

	generic_handle_irq_desc(irq, desc);
	return true;
}


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);
}
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
	3	*
	4	* This file contains the lowest level x86_64-specific interrupt
	5	* entry and irq statistics code. All the remaining irq logic is
	6	* done by the generic kernel/irq/ code and in the
	7	* x86_64-specific irq controller code. (e.g. i8259.c and
	8	* io_apic.c.)
	9	*/
	10
	11	#include <linux/kernel_stat.h>
	12	#include <linux/interrupt.h>
	13	#include <linux/seq_file.h>
	14	#include <linux/module.h>
76e4f660	15	#include <linux/delay.h>
bcbc4f20	16	#include <linux/ftrace.h>
5f66b2a0 JSR	17	#include <linux/uaccess.h>
5f66b2a0 JSR	18	#include <linux/smp.h>
1da177e4	19	#include <asm/io_apic.h>
95833c83	20	#include <asm/idle.h>
3819cd48	21	#include <asm/apic.h>
1da177e4	22
1b437c8c BG	23	DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
	24	EXPORT_PER_CPU_SYMBOL(irq_stat);
	25
d650a514 BG	26	DEFINE_PER_CPU(struct pt_regs *, irq_regs);
	27	EXPORT_PER_CPU_SYMBOL(irq_regs);
	28
55af7796 MH	29	int sysctl_panic_on_stackoverflow;
55af7796 MH	30
4961f10e ES	31	/*
	32	* Probabilistic stack overflow check:
	33	*
	34	* Only check the stack in process context, because everything else
	35	* runs on the big interrupt stacks. Checking reliably is too expensive,
	36	* so we just check from interrupts.
	37	*/
	38	static inline void stack_overflow_check(struct pt_regs *regs)
	39	{
f377fa12	40	#ifdef CONFIG_DEBUG_STACKOVERFLOW
37fe6a42 MH	41	struct orig_ist *oist;
	42	u64 irq_stack_top, irq_stack_bottom;
	43	u64 estack_top, estack_bottom;
c9f4f06d	44	u64 curbase = (u64)task_stack_page(current);
f377fa12	45
69682b62 MH	46	if (user_mode_vm(regs))
	47	return;
	48
467e6b7a MH	49	if (regs->sp >= curbase + sizeof(struct thread_info) +
	50	sizeof(struct pt_regs) + 128 &&
	51	regs->sp <= curbase + THREAD_SIZE)
37fe6a42 MH	52	return;
	53
	54	irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack);
	55	irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
	56	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
	57	return;
	58
	59	oist = &__get_cpu_var(orig_ist);
	60	estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ;
	61	estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
	62	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
	63	return;
f377fa12	64
37fe6a42 MH	65	WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n",
	66	current->comm, curbase, regs->sp,
	67	irq_stack_top, irq_stack_bottom,
	68	estack_top, estack_bottom);
55af7796 MH	69
	70	if (sysctl_panic_on_stackoverflow)
	71	panic("low stack detected by irq handler - check messages\n");
4961f10e	72	#endif
f377fa12	73	}
4961f10e	74
9b2b76a3 JF	75	bool handle_irq(unsigned irq, struct pt_regs *regs)
	76	{
	77	struct irq_desc *desc;
	78
	79	stack_overflow_check(regs);
	80
	81	desc = irq_to_desc(irq);
	82	if (unlikely(!desc))
	83	return false;
	84
	85	generic_handle_irq_desc(irq, desc);
	86	return true;
	87	}
	88
ed6b676c AK	89
	90	extern void call_softirq(void);
	91
	92	asmlinkage void do_softirq(void)
	93	{
5f66b2a0 JSR	94	__u32 pending;
5f66b2a0 JSR	95	unsigned long flags;
ed6b676c	96
5f66b2a0 JSR	97	if (in_interrupt())
5f66b2a0 JSR	98	return;
ed6b676c	99
5f66b2a0 JSR	100	local_irq_save(flags);
	101	pending = local_softirq_pending();
	102	/* Switch to interrupt stack */
	103	if (pending) {
ed6b676c	104	call_softirq();
2601e64d IM	105	WARN_ON_ONCE(softirq_count());
2601e64d IM	106	}
5f66b2a0	107	local_irq_restore(flags);
ed6b676c	108	}