diff options
Diffstat (limited to 'grub-core/commands/memrw.c')
| -rw-r--r-- | grub-core/commands/memrw.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/grub-core/commands/memrw.c b/grub-core/commands/memrw.c new file mode 100644 index 0000000..d401a6d --- /dev/null +++ b/grub-core/commands/memrw.c @@ -0,0 +1,158 @@ +/* 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); +} |