hw_irq.h

讲述linux的初始化过程

#ifndef _ASM_HW_IRQ_H
#define _ASM_HW_IRQ_H

/*
 *	linux/include/asm/hw_irq.h
 *
 *	(C) 1992, 1993 Linus Torvalds, (C) 1997 Ingo Molnar
 *
 *	moved some of the old arch/i386/kernel/irq.h to here. VY
 *
 *	IRQ/IPI changes taken from work by Thomas Radke
 *	<[e-mail]>
 */

#include <linux/config.h>
#include <asm/irq.h>

/*
 * IDT vectors usable for external interrupt sources start
 * at 0x20:
 */
#define FIRST_EXTERNAL_VECTOR	0x20

#define SYSCALL_VECTOR		0x80

/*
 * Vectors 0x20-0x2f are used for ISA interrupts.
 */

/*
 * Special IRQ vectors used by the SMP architecture, 0xf0-0xff
 *
 *  some of the following vectors are 'rare', they are merged
 *  into a single vector (CALL_FUNCTION_VECTOR) to save vector space.
 *  TLB, reschedule and local APIC vectors are performance-critical.
 *
 *  Vectors 0xf0-0xfa are free (reserved for future Linux use).
 */
#define SPURIOUS_APIC_VECTOR	0xff
#define ERROR_APIC_VECTOR	0xfe
#define INVALIDATE_TLB_VECTOR	0xfd
#define RESCHEDULE_VECTOR	0xfc
#define CALL_FUNCTION_VECTOR	0xfb

/*
 * Local APIC timer IRQ vector is on a different priority level,
 * to work around the 'lost local interrupt if more than 2 IRQ
 * sources per level' errata.
 */
#define LOCAL_TIMER_VECTOR	0xef

/*
 * First APIC vector available to drivers: (vectors 0x30-0xee)
 * we start at 0x31 to spread out vectors evenly between priority
 * levels. (0x80 is the syscall vector)
 */
#define FIRST_DEVICE_VECTOR	0x31
#define FIRST_SYSTEM_VECTOR	0xef

extern int irq_vector[NR_IRQS];
#define IO_APIC_VECTOR(irq)	irq_vector[irq]

/*
 * Various low-level irq details needed by irq.c, process.c,
 * time.c, io_apic.c and smp.c
 *
 * Interrupt entry/exit code at both C and assembly level
 */

extern void mask_irq(unsigned int irq);
extern void unmask_irq(unsigned int irq);
extern void disable_8259A_irq(unsigned int irq);
extern void enable_8259A_irq(unsigned int irq);
extern int i8259A_irq_pending(unsigned int irq);
extern void make_8259A_irq(unsigned int irq);
extern void init_8259A(int aeoi);
extern void FASTCALL(send_IPI_self(int vector));
extern void init_VISWS_APIC_irqs(void);
extern void setup_IO_APIC(void);
extern void disable_IO_APIC(void);
extern void print_IO_APIC(void);
extern int IO_APIC_get_PCI_irq_vector(int bus, int slot, int fn);
extern void send_IPI(int dest, int vector);

extern unsigned long io_apic_irqs;
extern volatile unsigned long irq_err_count;

extern char _stext, _etext;

#define IO_APIC_IRQ(x) (((x) >= 16) || ((1<<(x)) & io_apic_irqs))

#define __STR(x) #x
#define STR(x) __STR(x)

#define SAVE_ALL \
	"cld\n\t" \
	"pushl %es\n\t" \
	"pushl %ds\n\t" \
	"pushl %eax\n\t" \
	"pushl %ebp\n\t" \
	"pushl %edi\n\t" \
	"pushl %esi\n\t" \
	"pushl %edx\n\t" \
	"pushl %ecx\n\t" \
	"pushl %ebx\n\t" \
	"movl $" STR(__KERNEL_DS) ",%edx\n\t" \
	"movl %edx,%ds\n\t" \
	"movl %edx,%es\n\t"

#define IRQ_NAME2(nr) nr##_interrupt(void)
#define IRQ_NAME(nr) IRQ_NAME2(IRQ##nr)

#define GET_CURRENT \
	"movl %esp, %ebx\n\t" \
	"andl $-8192, %ebx\n\t"

/*
 *	SMP has a few special interrupts for IPI messages
 */

	/* there is a second layer of macro just to get the symbolic
	   name for the vector evaluated. This change is for RTLinux */
#define BUILD_SMP_INTERRUPT(x,v) XBUILD_SMP_INTERRUPT(x,v)
#define XBUILD_SMP_INTERRUPT(x,v)\
asmlinkage void x(void); \
asmlinkage void call_##x(void); \
__asm__( \
"\n"__ALIGN_STR"\n" \
SYMBOL_NAME_STR(x) ":\n\t" \
	"pushl $"#v"\n\t" \
	SAVE_ALL \
	SYMBOL_NAME_STR(call_##x)":\n\t" \
	"call "SYMBOL_NAME_STR(smp_##x)"\n\t" \
	"jmp ret_from_intr\n");

#define BUILD_SMP_TIMER_INTERRUPT(x,v) XBUILD_SMP_TIMER_INTERRUPT(x,v)
#define XBUILD_SMP_TIMER_INTERRUPT(x,v) \
asmlinkage void x(struct pt_regs * regs); \
asmlinkage void call_##x(void); \
__asm__( \
"\n"__ALIGN_STR"\n" \
SYMBOL_NAME_STR(x) ":\n\t" \
	"pushl $"#v"\n\t" \
	SAVE_ALL \
	"movl %esp,%eax\n\t" \
	"pushl %eax\n\t" \
	SYMBOL_NAME_STR(call_##x)":\n\t" \
	"call "SYMBOL_NAME_STR(smp_##x)"\n\t" \
	"addl $4,%esp\n\t" \
	"jmp ret_from_intr\n");

#define BUILD_COMMON_IRQ() \
asmlinkage void call_do_IRQ(void); \
__asm__( \
	"\n" __ALIGN_STR"\n" \
	"common_interrupt:\n\t" \
	SAVE_ALL \
	"pushl $ret_from_intr\n\t" \
	SYMBOL_NAME_STR(call_do_IRQ)":\n\t" \
	"jmp "SYMBOL_NAME_STR(do_IRQ));

/* 
 * subtle. orig_eax is used by the signal code to distinct between
 * system calls and interrupted 'random user-space'. Thus we have
 * to put a negative value into orig_eax here. (the problem is that
 * both system calls and IRQs want to have small integer numbers in
 * orig_eax, and the syscall code has won the optimization conflict ;)
 *
 * Subtle as a pigs ear.  VY
 */

#define BUILD_IRQ(nr) \
asmlinkage void IRQ_NAME(nr); \
__asm__( \
"\n"__ALIGN_STR"\n" \
SYMBOL_NAME_STR(IRQ) #nr "_interrupt:\n\t" \
	"pushl $"#nr"-256\n\t" \
	"jmp common_interrupt");

extern unsigned long prof_cpu_mask;
extern unsigned int * prof_buffer;
extern unsigned long prof_len;
extern unsigned long prof_shift;

/*
 * x86 profiling function, SMP safe. We might want to do this in
 * assembly totally?
 */
static inline void x86_do_profile (unsigned long eip)
{
	if (!prof_buffer)
		return;

	/*
	 * Only measure the CPUs specified by /proc/irq/prof_cpu_mask.
	 * (default is all CPUs.)
	 */
	if (!((1<<smp_processor_id()) & prof_cpu_mask))
		return;

	eip -= (unsigned long) &_stext;
	eip >>= prof_shift;
	/*
	 * Don't ignore out-of-bounds EIP values silently,
	 * put them into the last histogram slot, so if
	 * present, they will show up as a sharp peak.
	 */
	if (eip > prof_len-1)
		eip = prof_len-1;
	atomic_inc((atomic_t *)&prof_buffer[eip]);
}

#ifdef CONFIG_SMP /*more of this file should probably be ifdefed SMP */
static inline void hw_resend_irq(struct hw_interrupt_type *h, unsigned int i) {
	if (IO_APIC_IRQ(i))
		send_IPI_self(IO_APIC_VECTOR(i));
}
#else
static inline void hw_resend_irq(struct hw_interrupt_type *h, unsigned int i) {}
#endif

#endif /* _ASM_HW_IRQ_H */