diff options
Diffstat (limited to 'host/lib/crossystem.c')
| -rw-r--r-- | host/lib/crossystem.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/host/lib/crossystem.c b/host/lib/crossystem.c index cf7600e4..c5c72cfe 100644 --- a/host/lib/crossystem.c +++ b/host/lib/crossystem.c @@ -16,6 +16,7 @@ #include "crossystem.h" #include "crossystem_vbnv.h" #include "host_common.h" +#include "flashrom.h" #include "subprocess.h" #include "vboot_struct.h" @@ -655,6 +656,107 @@ int VbSetSystemPropertyString(const char* name, const char* value) return -1; } +/** + * Get index of the last valid VBNV entry in an EEPROM. + * + * @param buf Pointer to the beginning of the EEPROM. + * @param buf_sz Size of the EEPROM. + * @param vbnv_size The size of a single VBNV entry for this device. + * + * @return The index of the last valid VBNV entry on success, or -1 on + * failure. + */ +static int vb2_nv_index(const uint8_t *buf, uint32_t buf_sz, int vbnv_size) +{ + int index; + uint8_t blank[VB2_NVDATA_SIZE_V2]; + + /* The size of the buffer should be an even multiple of the + VBNV size. */ + if (buf_sz % vbnv_size != 0) { + VB2_DIE("The VBNV in flash (%u bytes) is not an even multiple " + "of the VBNV size (%u bytes). This is likely a " + "firmware bug.\n", buf_sz, vbnv_size); + } + + memset(blank, 0xff, sizeof(blank)); + for (index = 0; index < buf_sz / vbnv_size; index++) { + if (!memcmp(blank, &buf[index * vbnv_size], vbnv_size)) + break; + } + + if (!index || index == buf_sz / vbnv_size) { + fprintf(stderr, "VBNV is either uninitialized or corrupted.\n"); + return -1; + } + + return index - 1; +} + +#define VBNV_FMAP_REGION "RW_NVRAM" + +int vb2_read_nv_storage_flashrom(struct vb2_context *ctx) +{ + int index; + int vbnv_size = vb2_nv_get_size(ctx); + uint8_t *flash_buf; + uint32_t flash_size; + + if (flashrom_read(FLASHROM_PROGRAMMER_INTERNAL_AP, VBNV_FMAP_REGION, + &flash_buf, &flash_size)) + return -1; + + index = vb2_nv_index(flash_buf, flash_size, vbnv_size); + if (index < 0) { + free(flash_buf); + return -1; + } + + memcpy(ctx->nvdata, &flash_buf[index * vbnv_size], vbnv_size); + free(flash_buf); + return 0; +} + +int vb2_write_nv_storage_flashrom(struct vb2_context *ctx) +{ + int rv = 0; + int current_index; + int next_index; + int vbnv_size = vb2_nv_get_size(ctx); + uint8_t *flash_buf; + uint32_t flash_size; + + if (flashrom_read(FLASHROM_PROGRAMMER_INTERNAL_AP, VBNV_FMAP_REGION, + &flash_buf, &flash_size)) + return -1; + + current_index = vb2_nv_index(flash_buf, flash_size, vbnv_size); + if (current_index < 0) { + rv = -1; + goto exit; + } + + next_index = current_index + 1; + if ((next_index + 1) * vbnv_size == flash_size) { + /* VBNV is full. Erase and write at beginning. */ + memset(flash_buf, 0xff, flash_size); + next_index = 0; + } + + memcpy(&flash_buf[next_index * vbnv_size], ctx->nvdata, vbnv_size); + if (flashrom_write(FLASHROM_PROGRAMMER_INTERNAL_AP, VBNV_FMAP_REGION, + flash_buf, flash_size)) { + rv = -1; + goto exit; + } + + exit: + free(flash_buf); + return rv; +} + +/* TODO(crbug.com/1090803): remove these mosys nvdata functions + (approx. October 2020). */ int vb2_read_nv_storage_mosys(struct vb2_context *ctx) { /* Reserve extra 32 bytes */ |