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/*
* Copyright (c) 2009 Corey Tabaka
* Copyright (c) 2015 Intel Corporation
* Copyright (c) 2016 Travis Geiselbrecht
*
* Use of this source code is governed by a MIT-style
* license that can be found in the LICENSE file or at
* https://opensource.org/licenses/MIT
*/
#include <lk/asm.h>
#include <arch/x86/descriptor.h>
#define NUM_INT 0x31
#define NUM_EXC 0x14
.text
/* interrupt service routine stubs */
_isr:
.set i, 0
.rept NUM_INT
.set isr_stub_start, .
.if i == 8 || (i >= 10 && i <= 14) || i == 17
nop /* error code pushed by exception */
nop /* 2 nops are the same length as push byte */
pushl $i /* interrupt number */
jmp interrupt_common
.else
pushl $0 /* fill in error code in iframe */
pushl $i /* interrupt number */
jmp interrupt_common
.endif
/* figure out the length of a single isr stub (usually 6 or 9 bytes) */
.set isr_stub_len, . - isr_stub_start
.set i, i + 1
.endr
/* annoying, but force AS to use the same (longer) encoding of jmp for all of the stubs */
.fill 256
FUNCTION(interrupt_common)
cld
pushl %gs /* save segment registers */
pushl %fs
pushl %es
pushl %ds
pusha /* save general purpose registers */
movl $DATA_SELECTOR, %eax /* put known good value in segment registers */
movl %eax, %gs
movl %eax, %fs
movl %eax, %es
movl %eax, %ds
movl %esp, %eax /* store pointer to iframe */
pushl %eax
call x86_exception_handler
popl %eax /* drop pointer to iframe */
popa /* restore general purpose registers */
popl %ds /* restore segment registers */
popl %es
popl %fs
popl %gs
addl $8, %esp /* drop exception number and error code */
iret
FUNCTION(setup_idt)
/* setup isr stub descriptors in the idt */
movl $_isr, %esi
movl $_idt, %edi
movl $NUM_INT, %ecx
.Lloop:
movl %esi, %ebx
movw %bx, (%edi) /* low word in IDT(n).low */
shrl $16, %ebx
movw %bx, 6(%edi) /* high word in IDT(n).high */
addl $isr_stub_len, %esi/* index the next ISR stub */
addl $8, %edi /* index the next IDT entry */
loop .Lloop
lidt _idtr
ret
.data
.align 8
.global _idtr
_idtr:
.short _idt_end - _idt - 1 /* IDT limit */
.int _idt
/* interrupt descriptor table (IDT) */
.global _idt
_idt:
.set i, 0
.rept NUM_INT-1
.short 0 /* low 16 bits of ISR offset (_isr#i & 0FFFFh) */
.short CODE_SELECTOR /* selector */
.byte 0
.byte 0x8e /* present, ring 0, 32-bit interrupt gate */
.short 0 /* high 16 bits of ISR offset (_isr#i / 65536) */
.set i, i + 1
.endr
/* syscall int (ring 3) */
_idt30:
.short 0 /* low 16 bits of ISR offset (_isr#i & 0FFFFh) */
.short CODE_SELECTOR /* selector */
.byte 0
.byte 0xee /* present, ring 3, 32-bit interrupt gate */
.short 0 /* high 16 bits of ISR offset (_isr#i / 65536) */
.global _idt_end
_idt_end:
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