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/* idt.c - routines for constructing IDT fot the GDB stub */
/*
* Copyright (C) 2006 Lubomir Kundrak
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <grub/machine/memory.h>
#include <grub/misc.h>
#include <grub/cpu/gdb.h>
#include <grub/gdb.h>
static struct grub_cpu_interrupt_gate grub_gdb_idt[GRUB_GDB_LAST_TRAP + 1]
__attribute__ ((aligned(16)));
/* Sets up a gate descriptor in the IDT table. */
static void
grub_idt_gate (struct grub_cpu_interrupt_gate *gate, void (*offset) (void),
grub_uint16_t selector, grub_uint8_t type, grub_uint8_t dpl)
{
gate->offset_lo = (int) offset & 0xffff;
gate->selector = selector & 0xffff;
gate->unused = 0;
gate->gate = (type & 0x1f) | ((dpl & 0x3) << 5) | 0x80;
gate->offset_hi = ((int) offset >> 16) & 0xffff;
}
static struct grub_cpu_idt_descriptor grub_gdb_orig_idt_desc
__attribute__ ((aligned(16)));
static struct grub_cpu_idt_descriptor grub_gdb_idt_desc
__attribute__ ((aligned(16)));
/* Set up interrupt and trap handler descriptors in IDT. */
void
grub_gdb_idtinit (void)
{
int i;
grub_uint16_t seg;
asm volatile ("xorl %%eax, %%eax\n"
"mov %%cs, %%ax\n" :"=a" (seg));
for (i = 0; i <= GRUB_GDB_LAST_TRAP; i++)
{
grub_idt_gate (&grub_gdb_idt[i],
grub_gdb_trapvec[i], seg,
GRUB_CPU_TRAP_GATE, 0);
}
grub_gdb_idt_desc.base = (grub_addr_t) grub_gdb_idt;
grub_gdb_idt_desc.limit = sizeof (grub_gdb_idt) - 1;
asm volatile ("sidt %0" : : "m" (grub_gdb_orig_idt_desc));
asm volatile ("lidt %0" : : "m" (grub_gdb_idt_desc));
}
void
grub_gdb_idtrestore (void)
{
asm volatile ("lidt %0" : : "m" (grub_gdb_orig_idt_desc));
}
void
grub_gdb_breakpoint (void)
{
asm volatile ("int $3");
}
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