arch/all-pc/boot/grub2-aros/grub-core/gdb/i386/idt.c

   1 /* idt.c - routines for constructing IDT fot the GDB stub */
   2 /*
   3  *  Copyright (C) 2006  Lubomir Kundrak
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #include <grub/machine/memory.h>
  21 #include <grub/misc.h>
  22 #include <grub/cpu/gdb.h>
  23 #include <grub/gdb.h>
  24
  25 static struct grub_cpu_interrupt_gate grub_gdb_idt[GRUB_GDB_LAST_TRAP + 1]
  26   __attribute__ ((aligned(16)));
  27
  28 /* Sets up a gate descriptor in the IDT table.  */
  29 static void
  30 grub_idt_gate (struct grub_cpu_interrupt_gate *gate, void (*offset) (void),
  31                grub_uint16_t selector, grub_uint8_t type, grub_uint8_t dpl)
  32 {
  33   gate->offset_lo = (int) offset & 0xffff;
  34   gate->selector = selector & 0xffff;
  35   gate->unused = 0;
  36   gate->gate = (type & 0x1f) | ((dpl & 0x3) << 5) | 0x80;
  37   gate->offset_hi = ((int) offset >> 16) & 0xffff;
  38 }
  39
  40 static struct grub_cpu_idt_descriptor grub_gdb_orig_idt_desc
  41   __attribute__ ((aligned(16)));
  42 static struct grub_cpu_idt_descriptor grub_gdb_idt_desc
  43   __attribute__ ((aligned(16)));
  44
  45 /* Set up interrupt and trap handler descriptors in IDT.  */
  46 void
  47 grub_gdb_idtinit (void)
  48 {
  49   int i;
  50   grub_uint16_t seg;
  51
  52   asm volatile ("xorl %%eax, %%eax\n"
  53                 "mov %%cs, %%ax\n" :"=a" (seg));
  54
  55   for (i = 0; i <= GRUB_GDB_LAST_TRAP; i++)
  56     {
  57       grub_idt_gate (&grub_gdb_idt[i],
  58                      grub_gdb_trapvec[i], seg,
  59                      GRUB_CPU_TRAP_GATE, 0);
  60     }
  61
  62   grub_gdb_idt_desc.base = (grub_addr_t) grub_gdb_idt;
  63   grub_gdb_idt_desc.limit = sizeof (grub_gdb_idt) - 1;
  64   asm volatile ("sidt %0" : : "m" (grub_gdb_orig_idt_desc));
  65   asm volatile ("lidt %0" : : "m" (grub_gdb_idt_desc));
  66 }
  67
  68 void
  69 grub_gdb_idtrestore (void)
  70 {
  71   asm volatile ("lidt %0" : : "m" (grub_gdb_orig_idt_desc));
  72 }
  73
  74 void
  75 grub_gdb_breakpoint (void)
  76 {
  77   asm volatile ("int $3");
  78 }