diff options
| -rw-r--r-- | src/drivers/smmstore/Kconfig | 32 | ||||
| -rw-r--r-- | src/drivers/smmstore/Makefile.inc | 3 | ||||
| -rw-r--r-- | src/drivers/smmstore/smi.c | 83 | ||||
| -rw-r--r-- | src/drivers/smmstore/store.c | 225 | ||||
| -rw-r--r-- | src/include/smmstore.h | 52 | ||||
| -rw-r--r-- | src/soc/intel/common/block/smm/smihandler.c | 26 |
6 files changed, 421 insertions, 0 deletions
diff --git a/src/drivers/smmstore/Kconfig b/src/drivers/smmstore/Kconfig new file mode 100644 index 0000000000..4bb48f7e08 --- /dev/null +++ b/src/drivers/smmstore/Kconfig @@ -0,0 +1,32 @@ +## +## This file is part of the coreboot project. +## +## Copyright (C) 2018 The Chromium OS Authors. All rights reserved. +## +## 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; version 2 of the License. +## +## 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. +## + +config SMMSTORE + bool "Support for flash based, SMM mediated data store" + default n + depends on BOOT_DEVICE_SUPPORTS_WRITES + select SPI_FLASH_SMM if BOOT_DEVICE_SPI_FLASH_RW_NOMMAP + +if SMMSTORE +config SMMSTORE_REGION + string "fmap region in which SMM store file is kept" + default "RW_LEGACY" if CHROMEOS + default "COREBOOT" + +config SMMSTORE_FILENAME + string "SMM store file name" + default "smm store" + +endif diff --git a/src/drivers/smmstore/Makefile.inc b/src/drivers/smmstore/Makefile.inc new file mode 100644 index 0000000000..1cafe3a3cf --- /dev/null +++ b/src/drivers/smmstore/Makefile.inc @@ -0,0 +1,3 @@ +ramstage-$(CONFIG_SMMSTORE) += store.c + +smm-$(CONFIG_SMMSTORE) += store.c smi.c diff --git a/src/drivers/smmstore/smi.c b/src/drivers/smmstore/smi.c new file mode 100644 index 0000000000..3bcf564e1a --- /dev/null +++ b/src/drivers/smmstore/smi.c @@ -0,0 +1,83 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2018 The Chromium OS Authors. All rights reserved. + * + * 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; version 2 of the License. + * + * 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. + */ + +#include <console/console.h> +#include <smmstore.h> +#include <stddef.h> +#include <stdint.h> + +/* + * Check that the given range is legal. + * + * Legal means: + * - not pointing into SMRAM + * - ...? + * + * returns 0 on success, -1 on failure + */ +static int range_check(void *start, size_t size) +{ + // TODO: fill in + return 0; +} + +/* Param is usually EBX, ret in EAX */ +uint32_t smmstore_exec(uint8_t command, void *param) +{ + uint32_t ret = SMMSTORE_RET_FAILURE; + + switch (command) { + case SMMSTORE_CMD_READ: { + printk(BIOS_DEBUG, "Reading from SMM store\n"); + struct smmstore_params_read *params = param; + + if (range_check(params->buf, params->bufsize) != 0) + break; + + if (smmstore_read_region(params->buf, ¶ms->bufsize) == 0) + ret = SMMSTORE_RET_SUCCESS; + break; + } + + case SMMSTORE_CMD_APPEND: { + printk(BIOS_DEBUG, "Appending into SMM store\n"); + struct smmstore_params_append *params = param; + + if (range_check(params->key, params->keysize) != 0) + break; + if (range_check(params->val, params->valsize) != 0) + break; + + if (smmstore_append_data(params->key, params->keysize, + params->val, params->valsize) == 0) + ret = SMMSTORE_RET_SUCCESS; + break; + } + + case SMMSTORE_CMD_CLEAR: { + if (smmstore_clear_region() == 0) + ret = SMMSTORE_RET_SUCCESS; + break; + } + + default: + printk(BIOS_DEBUG, + "Unknown SMM store command: 0x%02x\n", command); + ret = SMMSTORE_RET_UNSUPPORTED; + break; + } + + return ret; +} diff --git a/src/drivers/smmstore/store.c b/src/drivers/smmstore/store.c new file mode 100644 index 0000000000..67d38ee143 --- /dev/null +++ b/src/drivers/smmstore/store.c @@ -0,0 +1,225 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2018 The Chromium OS Authors. All rights reserved. + * + * 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; version 2 of the License. + * + * 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. + */ + +#include <boot_device.h> +#include <cbfs.h> +#include <commonlib/region.h> +#include <console/console.h> +#include <smmstore.h> +#include <string.h> + +/* + * The region format is still not finalized, but so far it looks like this: + * ( + * uint32le_t key_sz + * uint32le_t value_sz + * uint8_t key[key_sz] + * uint8_t value[value_sz] + * uint8_t active + * align to 4 bytes + * )* + * uint32le_t endmarker = 0xffffffff + * + * active needs to be set to 0x00 for the entry to be valid. This satisfies + * the constraint that entries are either complete or will be ignored, as long + * as flash is written sequentially and into a fully erased block. + * + * Future additions to the format will split the region in half with an active + * block marker to allow safe compaction (ie. write the new data in the unused + * region, mark it active after the write completed). Otherwise a well-timed + * crash/reboot could clear out all variables. + */ + +/* + * Return a region device that points into the store file. + * + * It's the image builder's responsibility to make it block aligned so that + * erase works without destroying other data. + * + * It doesn't cache the location to cope with flash changing underneath (eg + * due to an update) + * + * returns 0 on success, -1 on failure + * outputs the valid store rdev in rstore + */ +static int lookup_store(struct region_device *rstore) +{ + struct cbfsf file; + if (cbfs_locate_file_in_region(&file, + CONFIG_SMMSTORE_REGION, CONFIG_SMMSTORE_FILENAME, NULL) < 0) { + printk(BIOS_WARNING, "smm store: " + "Unable to find SMM store file in region '%s'\n", + CONFIG_SMMSTORE_REGION); + return -1; + } + + cbfs_file_data(rstore, &file); + + return 0; +} + +/* + * Read entire store into user provided buffer + * + * returns 0 on success, -1 on failure + * writes up to `*bufsize` bytes into `buf` and updates `*bufsize` + */ +int smmstore_read_region(void *buf, ssize_t *bufsize) +{ + struct region_device store; + + if (bufsize == NULL) + return -1; + + *bufsize = 0; + if (lookup_store(&store) < 0) { + printk(BIOS_WARNING, "reading region failed\n"); + return -1; + } + + ssize_t tx = min(*bufsize, region_device_sz(&store)); + *bufsize = rdev_readat(&store, buf, 0, tx); + + if (*bufsize < 0) + return -1; + + return 0; +} + +/* + * Append data to region + * + * Returns 0 on success, -1 on failure + */ +int smmstore_append_data(void *key, uint32_t key_sz, + void *value, uint32_t value_sz) +{ + struct region_device store; + + if (lookup_store(&store) < 0) { + printk(BIOS_WARNING, "reading region failed\n"); + return -1; + } + + ssize_t data_sz = region_device_sz(&store); + + /* scan for end */ + ssize_t end = 0; + uint32_t k_sz, v_sz; + while (end < data_sz) { + /* make odd corner cases identifiable, eg. invalid v_sz */ + k_sz = 0; + + if (rdev_readat(&store, &k_sz, end, sizeof(k_sz)) < 0) { + printk(BIOS_WARNING, "failed reading key size\n"); + return -1; + } + + /* found the end */ + if (k_sz == 0xffffffff) + break; + + /* something is fishy here: + * Avoid wrapping (since data_size < MAX_UINT32_T / 2) while + * other problems are covered by the loop condition + */ + if (k_sz > data_sz) { + printk(BIOS_WARNING, "key size out of bounds\n"); + return -1; + } + + if (rdev_readat(&store, &v_sz, end + 4, sizeof(v_sz)) < 0) { + printk(BIOS_WARNING, "failed reading value size\n"); + return -1; + } + + if (v_sz > data_sz) { + printk(BIOS_WARNING, "value size out of bounds\n"); + return -1; + } + + end += 8 + k_sz + v_sz + 1; + end = ALIGN_UP(end, sizeof(uint32_t)); + } + + printk(BIOS_WARNING, "used smm store size might be 0x%zx bytes\n", end); + + if (k_sz != 0xffffffff) { + printk(BIOS_WARNING, + "eof of data marker looks invalid: 0x%x\n", k_sz); + return -1; + } + + printk(BIOS_WARNING, "used size looks legit\n"); + + printk(BIOS_WARNING, "open (%zx, %zx) for writing\n", + region_device_offset(&store), region_device_sz(&store)); + if (boot_device_rw_subregion(&store.region, &store) < 0) { + printk(BIOS_WARNING, "couldn't open store for writing\n"); + return -1; + } + + uint32_t record_sz = 8 + key_sz + value_sz + 1; + if (end + record_sz >= data_sz) { + printk(BIOS_WARNING, "not enough space for new data\n"); + return -1; + } + + if (rdev_writeat(&store, &key_sz, end, 4) != 4) { + printk(BIOS_WARNING, "failed writing key size\n"); + } + end += 4; + if (rdev_writeat(&store, &value_sz, end, 4) != 4) { + printk(BIOS_WARNING, "failed writing value size\n"); + } + end += 4; + if (rdev_writeat(&store, key, end, key_sz) != key_sz) { + printk(BIOS_WARNING, "failed writing key data\n"); + } + end += key_sz; + if (rdev_writeat(&store, value, end, value_sz) != value_sz) { + printk(BIOS_WARNING, "failed writing value data\n"); + } + end += value_sz; + uint8_t nul = 0; + if (rdev_writeat(&store, &nul, end, 1) != 1) { + printk(BIOS_WARNING, "failed writing termination\n"); + } + + return 0; +} + +/* + * Clear region + * + * Returns 0 on success, -1 on failure, including partial erase + */ +int smmstore_clear_region(void) +{ + struct region_device store; + + if (lookup_store(&store) < 0) { + printk(BIOS_WARNING, "smm store: reading region failed\n"); + return -1; + } + + ssize_t res = rdev_eraseat(&store, 0, region_device_sz(&store)); + if (res != region_device_sz(&store)) { + printk(BIOS_WARNING, "smm store: erasing region failed\n"); + return -1; + } + + return 0; +} diff --git a/src/include/smmstore.h b/src/include/smmstore.h new file mode 100644 index 0000000000..685a425dab --- /dev/null +++ b/src/include/smmstore.h @@ -0,0 +1,52 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2018 The Chromium OS Authors. All rights reserved. + * + * 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; version 2 of the License. + * + * 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. + */ + +#ifndef _SMMSTORE_H_ +#define _SMMSTORE_H_ + +#include <stddef.h> +#include <stdint.h> + +#define SMMSTORE_APM_CNT 0xed + +#define SMMSTORE_RET_SUCCESS 0 +#define SMMSTORE_RET_FAILURE 1 +#define SMMSTORE_RET_UNSUPPORTED 2 + +#define SMMSTORE_CMD_CLEAR 1 +#define SMMSTORE_CMD_READ 2 +#define SMMSTORE_CMD_APPEND 3 + +struct smmstore_params_read { + void *buf; + ssize_t bufsize; +}; + +struct smmstore_params_append { + void *key; + size_t keysize; + void *val; + size_t valsize; +}; + +/* SMM responder */ +uint32_t smmstore_exec(uint8_t command, void *param); + +/* implementation */ +int smmstore_read_region(void *buf, ssize_t *bufsize); +int smmstore_append_data(void *key, uint32_t key_sz, + void *value, uint32_t value_sz); +int smmstore_clear_region(void); +#endif diff --git a/src/soc/intel/common/block/smm/smihandler.c b/src/soc/intel/common/block/smm/smihandler.c index e4c13dd4b9..f90ac578e3 100644 --- a/src/soc/intel/common/block/smm/smihandler.c +++ b/src/soc/intel/common/block/smm/smihandler.c @@ -27,6 +27,7 @@ #include <intelblocks/pmclib.h> #include <intelblocks/smihandler.h> #include <intelblocks/uart.h> +#include <smmstore.h> #include <soc/nvs.h> #include <soc/pm.h> #include <soc/gpio.h> @@ -294,6 +295,27 @@ static void southbridge_smi_gsmi( save_state_ops->set_reg(io_smi, RAX, ret); } +static void southbridge_smi_store( + const struct smm_save_state_ops *save_state_ops) +{ + u8 sub_command, ret; + void *io_smi; + uint32_t reg_ebx; + + io_smi = find_save_state(save_state_ops, SMMSTORE_APM_CNT); + if (!io_smi) + return; + /* Command and return value in EAX */ + sub_command = (save_state_ops->get_reg(io_smi, RAX) >> 8) & 0xff; + + /* Parameter buffer in EBX */ + reg_ebx = save_state_ops->get_reg(io_smi, RBX); + + /* drivers/smmstore/smi.c */ + ret = smmstore_exec(sub_command, (void *)reg_ebx); + save_state_ops->set_reg(io_smi, RAX, ret); +} + static void finalize(void) { static int finalize_done; @@ -366,6 +388,10 @@ void smihandler_southbridge_apmc( if (IS_ENABLED(CONFIG_ELOG_GSMI)) southbridge_smi_gsmi(save_state_ops); break; + case SMMSTORE_APM_CNT: + if (IS_ENABLED(CONFIG_SMMSTORE)) + southbridge_smi_store(save_state_ops); + break; case APM_CNT_FINALIZE: finalize(); break; |