| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #include <boot_device.h> |
| #include <cbfs.h> |
| #include <fmap.h> |
| #include <commonlib/helpers.h> |
| #include <commonlib/region.h> |
| #include <console/console.h> |
| #include <smmstore.h> |
| #include <types.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. |
| */ |
| |
| static enum cb_err lookup_store_region(struct region *region) |
| { |
| if (CONFIG(SMMSTORE_IN_CBFS)) { |
| 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 CB_ERR; |
| } |
| struct region_device rdev; |
| cbfs_file_data(&rdev, &file); |
| *region = *region_device_region(&rdev); |
| } else { |
| if (fmap_locate_area(CONFIG_SMMSTORE_REGION, region)) { |
| printk(BIOS_WARNING, |
| "smm store: Unable to find SMM store FMAP region '%s'\n", |
| CONFIG_SMMSTORE_REGION); |
| return CB_ERR; |
| } |
| } |
| |
| return CB_SUCCESS; |
| } |
| |
| /* |
| * 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) |
| { |
| static struct region_device read_rdev, write_rdev; |
| static struct incoherent_rdev store_irdev; |
| struct region region; |
| const struct region_device *rdev; |
| |
| if (lookup_store_region(®ion) != CB_SUCCESS) |
| return -1; |
| |
| if (boot_device_ro_subregion(®ion, &read_rdev) < 0) |
| return -1; |
| |
| if (boot_device_rw_subregion(®ion, &write_rdev) < 0) |
| return -1; |
| |
| rdev = incoherent_rdev_init(&store_irdev, ®ion, &read_rdev, &write_rdev); |
| |
| if (rdev == NULL) |
| return -1; |
| |
| return rdev_chain(rstore, rdev, 0, region_device_sz(rdev)); |
| } |
| |
| /* |
| * 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; |
| |
| 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; |
| } |
| |
| static enum cb_err scan_end(struct region_device *store) |
| { |
| /* scan for end */ |
| ssize_t end = 0; |
| uint32_t k_sz, v_sz; |
| const ssize_t data_sz = region_device_sz(store); |
| 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 CB_ERR; |
| } |
| |
| /* 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 CB_ERR; |
| } |
| |
| if (rdev_readat(store, &v_sz, end + sizeof(k_sz), sizeof(v_sz)) < 0) { |
| printk(BIOS_WARNING, "failed reading value size\n"); |
| return CB_ERR; |
| } |
| |
| if (v_sz > data_sz) { |
| printk(BIOS_WARNING, "value size out of bounds\n"); |
| return CB_ERR; |
| } |
| |
| end += sizeof(k_sz) + sizeof(v_sz) + k_sz + v_sz + 1; |
| end = ALIGN_UP(end, sizeof(uint32_t)); |
| } |
| |
| printk(BIOS_DEBUG, "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 CB_ERR; |
| } |
| |
| if (rdev_chain(store, store, end, data_sz - end)) |
| return CB_ERR; |
| |
| return CB_SUCCESS; |
| |
| } |
| /* |
| * 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 offset = 0; |
| ssize_t size; |
| uint8_t nul = 0; |
| if (scan_end(&store) != CB_SUCCESS) |
| return -1; |
| |
| printk(BIOS_DEBUG, "used size looks legit\n"); |
| |
| printk(BIOS_DEBUG, "open (%zx, %zx) for writing\n", |
| region_device_offset(&store), region_device_sz(&store)); |
| |
| size = sizeof(key_sz) + sizeof(value_sz) + key_sz + value_sz |
| + sizeof(nul); |
| if (rdev_chain(&store, &store, 0, size)) { |
| printk(BIOS_WARNING, "not enough space for new data\n"); |
| return -1; |
| } |
| |
| if (rdev_writeat(&store, &key_sz, offset, sizeof(key_sz)) |
| != sizeof(key_sz)) { |
| printk(BIOS_WARNING, "failed writing key size\n"); |
| return -1; |
| } |
| offset += sizeof(key_sz); |
| if (rdev_writeat(&store, &value_sz, offset, sizeof(value_sz)) |
| != sizeof(value_sz)) { |
| printk(BIOS_WARNING, "failed writing value size\n"); |
| return -1; |
| } |
| offset += sizeof(value_sz); |
| if (rdev_writeat(&store, key, offset, key_sz) != key_sz) { |
| printk(BIOS_WARNING, "failed writing key data\n"); |
| return -1; |
| } |
| offset += key_sz; |
| if (rdev_writeat(&store, value, offset, value_sz) != value_sz) { |
| printk(BIOS_WARNING, "failed writing value data\n"); |
| return -1; |
| } |
| offset += value_sz; |
| if (rdev_writeat(&store, &nul, offset, sizeof(nul)) != sizeof(nul)) { |
| printk(BIOS_WARNING, "failed writing termination\n"); |
| return -1; |
| } |
| |
| 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; |
| } |