grub/grub-core/commands/i386/pc/halt.c

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/* halt.c - command to halt the computer. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2007,2009 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/dl.h>
#include <grub/misc.h>
#include <grub/extcmd.h>
#include <grub/i18n.h>
#include <grub/machine/int.h>
#include <grub/acpi.h>
static const struct grub_arg_option options[] =
{
{"no-apm", 'n', 0, N_("Do not use APM to halt the computer."), 0, 0},
{0, 0, 0, 0, 0, 0}
};
static inline void __attribute__ ((noreturn))
stop (void)
{
while (1)
{
asm volatile ("hlt");
}
}
/*
* Halt the system, using APM if possible. If NO_APM is true, don't use
* APM even if it is available.
*/
void
grub_halt (int no_apm)
{
struct grub_bios_int_registers regs;
grub_acpi_halt ();
if (no_apm)
stop ();
/* detect APM */
regs.eax = 0x5300;
regs.ebx = 0;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x15, &regs);
if (regs.flags & GRUB_CPU_INT_FLAGS_CARRY)
stop ();
/* disconnect APM first */
regs.eax = 0x5304;
regs.ebx = 0;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x15, &regs);
/* connect APM */
regs.eax = 0x5301;
regs.ebx = 0;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x15, &regs);
if (regs.flags & GRUB_CPU_INT_FLAGS_CARRY)
stop ();
/* set APM protocol level - 1.1 or bust. (this covers APM 1.2 also) */
regs.eax = 0x530E;
regs.ebx = 0;
regs.ecx = 0x0101;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x15, &regs);
if (regs.flags & GRUB_CPU_INT_FLAGS_CARRY)
stop ();
/* set the power state to off */
regs.eax = 0x5307;
regs.ebx = 1;
regs.ecx = 3;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x15, &regs);
/* shouldn't reach here */
stop ();
}
static grub_err_t
grub_cmd_halt (grub_extcmd_context_t ctxt,
int argc __attribute__ ((unused)),
char **args __attribute__ ((unused)))
{
struct grub_arg_list *state = ctxt->state;
int no_apm = 0;
if (state[0].set)
no_apm = 1;
grub_halt (no_apm);
return 0;
}
static grub_extcmd_t cmd;
GRUB_MOD_INIT(halt)
{
cmd = grub_register_extcmd ("halt", grub_cmd_halt, 0, "[-n]",
N_("Halt the system, if possible using APM."),
options);
}
GRUB_MOD_FINI(halt)
{
grub_unregister_extcmd (cmd);
}