Commit 9b2b76a3 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
Browse files

x86: add handle_irq() to allow interrupt injection 



Xen uses a different interrupt path, so introduce handle_irq() to
allow interrupts to be inserted into the normal interrupt path.  This
is handled slightly differently on 32 and 64-bit.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent cc6c5006

arch/x86/include/asm/irq.h

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ extern void fixup_irqs(void); 
extern unsigned int do_IRQ(struct pt_regs *regs);

extern void init_IRQ(void);

extern void native_init_IRQ(void);

extern bool handle_irq(unsigned irq, struct pt_regs *regs);



/* Interrupt vector management */

extern DECLARE_BITMAP(used_vectors, NR_VECTORS);

arch/x86/kernel/irq_32.c

+21 −13
Original line number Diff line number Diff line
@@ -191,6 +191,26 @@ static inline int 
execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; }

#endif



bool handle_irq(unsigned irq, struct pt_regs *regs)

{

	struct irq_desc *desc;

	int overflow;



	overflow = check_stack_overflow();



	desc = irq_to_desc(irq);

	if (unlikely(!desc))

		return false;



	if (!execute_on_irq_stack(overflow, desc, irq)) {

		if (unlikely(overflow))

			print_stack_overflow();

		desc->handle_irq(irq, desc);

	}



	return true;

}



/*

 * do_IRQ handles all normal device IRQ's (the special

 * SMP cross-CPU interrupts have their own specific
@@ -200,31 +220,19 @@ unsigned int do_IRQ(struct pt_regs *regs) 
{

	struct pt_regs *old_regs;

	/* high bit used in ret_from_ code */

	int overflow;

	unsigned vector = ~regs->orig_ax;

	struct irq_desc *desc;

	unsigned irq;





	old_regs = set_irq_regs(regs);

	irq_enter();

	irq = __get_cpu_var(vector_irq)[vector];



	overflow = check_stack_overflow();



	desc = irq_to_desc(irq);

	if (unlikely(!desc)) {

	if (!handle_irq(irq, regs)) {

		printk(KERN_EMERG "%s: cannot handle IRQ %d vector %#x cpu %d\n",

					__func__, irq, vector, smp_processor_id());

		BUG();

	}



	if (!execute_on_irq_stack(overflow, desc, irq)) {

		if (unlikely(overflow))

			print_stack_overflow();

		desc->handle_irq(irq, desc);

	}



	irq_exit();

	set_irq_regs(old_regs);

	return 1;

arch/x86/kernel/irq_64.c

+16 −7
Original line number Diff line number Diff line
@@ -48,6 +48,20 @@ static inline void stack_overflow_check(struct pt_regs *regs) 
#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;

}



/*

 * do_IRQ handles all normal device IRQ's (the special

 * SMP cross-CPU interrupts have their own specific
@@ -56,7 +70,6 @@ static inline void stack_overflow_check(struct pt_regs *regs) 
asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs)

{

	struct pt_regs *old_regs = set_irq_regs(regs);

	struct irq_desc *desc;



	/* high bit used in ret_from_ code  */

	unsigned vector = ~regs->orig_ax;
@@ -64,14 +77,10 @@ asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs) 


	exit_idle();

	irq_enter();

	irq = __get_cpu_var(vector_irq)[vector];



	stack_overflow_check(regs);

	irq = __get_cpu_var(vector_irq)[vector];



	desc = irq_to_desc(irq);

	if (likely(desc))

		generic_handle_irq_desc(irq, desc);

	else {

	if (!handle_irq(irq, regs)) {

		if (!disable_apic)

			ack_APIC_irq();

CRA Git | Maintained and supported by SUSTech CRA and CCSE