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/* memrw.c - command to read / write physical memory */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 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/env.h>
#include <grub/i18n.h>
#include <grub/lockdown.h>
GRUB_MOD_LICENSE ("GPLv3+");
static grub_extcmd_t cmd_read_byte, cmd_read_word, cmd_read_dword;
static grub_command_t cmd_write_byte, cmd_write_word, cmd_write_dword;
static const struct grub_arg_option options[] =
{
{0, 'v', 0, N_("Save read value into variable VARNAME."),
N_("VARNAME"), ARG_TYPE_STRING},
{0, 0, 0, 0, 0, 0}
};
static grub_err_t
grub_cmd_read (grub_extcmd_context_t ctxt, int argc, char **argv)
{
grub_addr_t addr;
grub_uint32_t value = 0;
char buf[sizeof ("XXXXXXXX")];
if (argc != 1)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
addr = grub_strtoul (argv[0], 0, 0);
switch (ctxt->extcmd->cmd->name[sizeof ("read_") - 1])
{
case 'd':
value = *((volatile grub_uint32_t *) addr);
break;
case 'w':
value = *((volatile grub_uint16_t *) addr);
break;
case 'b':
value = *((volatile grub_uint8_t *) addr);
break;
}
if (ctxt->state[0].set)
{
grub_snprintf (buf, sizeof (buf), "%x", value);
grub_env_set (ctxt->state[0].arg, buf);
}
else
grub_printf ("0x%x\n", value);
return 0;
}
static grub_err_t
grub_cmd_write (grub_command_t cmd, int argc, char **argv)
{
grub_addr_t addr;
grub_uint32_t value;
grub_uint32_t mask = 0xffffffff;
if (argc != 2 && argc != 3)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two arguments expected"));
addr = grub_strtoul (argv[0], 0, 0);
value = grub_strtoul (argv[1], 0, 0);
if (argc == 3)
mask = grub_strtoul (argv[2], 0, 0);
value &= mask;
switch (cmd->name[sizeof ("write_") - 1])
{
case 'd':
if (mask != 0xffffffff)
*((volatile grub_uint32_t *) addr)
= (*((volatile grub_uint32_t *) addr) & ~mask) | value;
else
*((volatile grub_uint32_t *) addr) = value;
break;
case 'w':
if ((mask & 0xffff) != 0xffff)
*((volatile grub_uint16_t *) addr)
= (*((volatile grub_uint16_t *) addr) & ~mask) | value;
else
*((volatile grub_uint16_t *) addr) = value;
break;
case 'b':
if ((mask & 0xff) != 0xff)
*((volatile grub_uint8_t *) addr)
= (*((volatile grub_uint8_t *) addr) & ~mask) | value;
else
*((volatile grub_uint8_t *) addr) = value;
break;
}
return 0;
}
GRUB_MOD_INIT(memrw)
{
cmd_read_byte =
grub_register_extcmd ("read_byte", grub_cmd_read, 0,
N_("ADDR"), N_("Read 8-bit value from ADDR."),
options);
cmd_read_word =
grub_register_extcmd ("read_word", grub_cmd_read, 0,
N_("ADDR"), N_("Read 16-bit value from ADDR."),
options);
cmd_read_dword =
grub_register_extcmd ("read_dword", grub_cmd_read, 0,
N_("ADDR"), N_("Read 32-bit value from ADDR."),
options);
cmd_write_byte =
grub_register_command_lockdown ("write_byte", grub_cmd_write,
N_("ADDR VALUE [MASK]"),
N_("Write 8-bit VALUE to ADDR."));
cmd_write_word =
grub_register_command_lockdown ("write_word", grub_cmd_write,
N_("ADDR VALUE [MASK]"),
N_("Write 16-bit VALUE to ADDR."));
cmd_write_dword =
grub_register_command_lockdown ("write_dword", grub_cmd_write,
N_("ADDR VALUE [MASK]"),
N_("Write 32-bit VALUE to ADDR."));
}
GRUB_MOD_FINI(memrw)
{
grub_unregister_extcmd (cmd_read_byte);
grub_unregister_extcmd (cmd_read_word);
grub_unregister_extcmd (cmd_read_dword);
grub_unregister_command (cmd_write_byte);
grub_unregister_command (cmd_write_word);
grub_unregister_command (cmd_write_dword);
}
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