irq.h

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#ifndef _ASM_IRQ_H
#define _ASM_IRQ_H

/**
*

 *      linux/include/asm/irq.h
 *
 *      (C) 1992, 1993 Linus Torvalds


*/

#include <linux/segment.h>
#include <linux/linkage.h>

extern void disable_irq(unsigned int);
extern void enable_irq(unsigned int);

#define __STR(x) #x
#define STR(x) __STR(x)
 
#define SAVE_ALL \
        "cld\n\t" \
        "push %gs\n\t" \
        "push %fs\n\t" \
        "push %es\n\t" \
        "push %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" \
        "mov %dx,%ds\n\t" \
        "mov %dx,%es\n\t" \
        "movl $" STR(USER_DS) ",%edx\n\t" \
        "mov %dx,%fs\n\t"   \
        "movl $0,%edx\n\t"  \
        "movl %edx,%db7\n\t"

/**
*

 * SAVE_MOST/RESTORE_MOST is used for the faster version of IRQ handlers,
 * installed by using the SA_INTERRUPT flag. These kinds of IRQ's don't
 * call the routines that do signal handling etc on return, and can have
 * more relaxed register-saving etc. They are also atomic, and are thus
 * suited for small, fast interrupts like the serial lines or the harddisk
 * drivers, which don't actually need signal handling etc.
 *
 * Also note that we actually save only those registers that are used in
 * C subroutines (%eax, %edx and %ecx), so if you do something weird,
 * you're on your own. The only segments that are saved (not counting the
 * automatic stack and code segment handling) are %ds and %es, and they
 * point to kernel space. No messing around with %fs here.


*/
#define SAVE_MOST \
        "cld\n\t" \
        "push %es\n\t" \
        "push %ds\n\t" \
        "pushl %eax\n\t" \
        "pushl %edx\n\t" \
        "pushl %ecx\n\t" \
        "movl $" STR(KERNEL_DS) ",%edx\n\t" \
        "mov %dx,%ds\n\t" \
        "mov %dx,%es\n\t"

#define RESTORE_MOST \
        "popl %ecx\n\t" \
        "popl %edx\n\t" \
        "popl %eax\n\t" \
        "pop %ds\n\t" \
        "pop %es\n\t" \
        "iret"

/**
*

 * The "inb" instructions are not needed, but seem to change the timings
 * a bit - without them it seems that the harddisk driver won't work on
 * all hardware. Arghh.


*/
#define ACK_FIRST(mask) \
        "inb $0x21,%al\n\t" \
        "jmp 1f\n" \
        "1:\tjmp 1f\n" \
        "1:\torb $" #mask ",_cache_21\n\t" \
        "movb _cache_21,%al\n\t" \
        "outb %al,$0x21\n\t" \
        "jmp 1f\n" \
        "1:\tjmp 1f\n" \
        "1:\tmovb $0x20,%al\n\t" \
        "outb %al,$0x20\n\t"

#define ACK_SECOND(mask) \
        "inb $0xA1,%al\n\t" \
        "jmp 1f\n" \
        "1:\tjmp 1f\n" \
        "1:\torb $" #mask ",_cache_A1\n\t" \
        "movb _cache_A1,%al\n\t" \
        "outb %al,$0xA1\n\t" \
        "jmp 1f\n" \
        "1:\tjmp 1f\n" \
        "1:\tmovb $0x20,%al\n\t" \
        "outb %al,$0xA0\n\t" \
        "jmp 1f\n" \
        "1:\tjmp 1f\n" \
        "1:\toutb %al,$0x20\n\t"

#define UNBLK_FIRST(mask) \
        "inb $0x21,%al\n\t" \
        "jmp 1f\n" \
        "1:\tjmp 1f\n" \
        "1:\tandb $~(" #mask "),_cache_21\n\t" \
        "movb _cache_21,%al\n\t" \
        "outb %al,$0x21\n\t"

#define UNBLK_SECOND(mask) \
        "inb $0xA1,%al\n\t" \
        "jmp 1f\n" \
        "1:\tjmp 1f\n" \
        "1:\tandb $~(" #mask "),_cache_A1\n\t" \
        "movb _cache_A1,%al\n\t" \
        "outb %al,$0xA1\n\t"

#define IRQ_NAME2(nr) nr##_interrupt(void)
#define IRQ_NAME(nr) IRQ_NAME2(IRQ##nr)
#define FAST_IRQ_NAME(nr) IRQ_NAME2(fast_IRQ##nr)
#define BAD_IRQ_NAME(nr) IRQ_NAME2(bad_IRQ##nr)
        
#define BUILD_IRQ(chip,nr,mask) \
asmlinkage void IRQ_NAME(nr); \
asmlinkage void FAST_IRQ_NAME(nr); \
asmlinkage void BAD_IRQ_NAME(nr); \
__asm__( \
"\n.align 4\n" \
"_IRQ" #nr "_interrupt:\n\t" \
        "pushl $-"#nr"-2\n\t" \
        SAVE_ALL \
        ACK_##chip(mask) \
        "incl _intr_count\n\t"\
        "sti\n\t" \
        "movl %esp,%ebx\n\t" \
        "pushl %ebx\n\t" \
        "pushl $" #nr "\n\t" \
        "call _do_IRQ\n\t" \
        "addl $8,%esp\n\t" \
        "cli\n\t" \
        UNBLK_##chip(mask) \
        "decl _intr_count\n\t" \
        "jmp ret_from_sys_call\n" \
"\n.align 4\n" \
"_fast_IRQ" #nr "_interrupt:\n\t" \
        SAVE_MOST \
        ACK_##chip(mask) \
        "incl _intr_count\n\t" \
        "pushl $" #nr "\n\t" \
        "call _do_fast_IRQ\n\t" \
        "addl $4,%esp\n\t" \
        "cli\n\t" \
        UNBLK_##chip(mask) \
        "decl _intr_count\n\t" \
        RESTORE_MOST \
"\n\n.align 4\n" \
"_bad_IRQ" #nr "_interrupt:\n\t" \
        SAVE_MOST \
        ACK_##chip(mask) \
        RESTORE_MOST);

#endif

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