/* * Firmware Interface Table support. * * Copyright (C) 2012 Google Inc. * * 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 <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "fit.h" /* FIXME: This code assumes it is being executed on a little endian machine. */ #define FIT_POINTER_LOCATION 0xffffffc0 #define FIT_TABLE_LOWEST_ADDRESS ((uint32_t)(-(16 << 20))) #define FIT_ENTRY_CHECKSUM_VALID 0x80 #define FIT_TYPE_HEADER 0x0 #define FIT_HEADER_VERSION 0x0100 #define FIT_HEADER_ADDRESS "_FIT_ " #define FIT_TYPE_MICROCODE 0x1 #define FIT_MICROCODE_VERSION 0x0100 struct fit_entry { uint64_t address; uint32_t size_reserved; uint16_t version; uint8_t type_checksum_valid; uint8_t checksum; } __attribute__ ((packed)); struct fit_table { struct fit_entry header; struct fit_entry entries[]; } __attribute__ ((packed)); struct microcode_header { uint32_t version; uint32_t revision; uint32_t date; uint32_t processor_signature; uint32_t checksum; uint32_t loader_revision; uint32_t processor_flags; uint32_t data_size; uint32_t total_size; uint8_t reserved[12]; } __attribute__ ((packed)); struct microcode_entry { int offset; int size; }; static inline void *rom_buffer_pointer(struct buffer *buffer, int offset) { return &buffer->data[offset]; } static inline int fit_entry_size_bytes(struct fit_entry *entry) { return (entry->size_reserved & 0xffffff) << 4; } static inline void fit_entry_update_size(struct fit_entry *entry, int size_bytes) { /* Size is multiples of 16 bytes. */ entry->size_reserved = (size_bytes >> 4) & 0xffffff; } static inline void fit_entry_add_size(struct fit_entry *entry, int size_bytes) { int size = fit_entry_size_bytes(entry); size += size_bytes; fit_entry_update_size(entry, size); } static inline int fit_entry_type(struct fit_entry *entry) { return entry->type_checksum_valid & ~FIT_ENTRY_CHECKSUM_VALID; } /* * Get an offset from a host pointer. This function assumes the ROM is located * in the host address space at [4G - romsize -> 4G). It also assume all * pointers have values within this address range. */ static inline int ptr_to_offset(fit_offset_converter_t helper, const struct buffer *region, uint32_t host_ptr) { return helper(region, -host_ptr); } /* * Get a pointer from an offset. This function assumes the ROM is located * in the host address space at [4G - romsize -> 4G). It also assume all * pointers have values within this address range. */ static inline uint32_t offset_to_ptr(fit_offset_converter_t helper, const struct buffer *region, int offset) { return -helper(region, offset); } static struct fit_table *locate_fit_table(fit_offset_converter_t offset_helper, struct buffer *buffer) { struct fit_table *table; uint32_t *fit_pointer; fit_pointer = rom_buffer_pointer(buffer, ptr_to_offset(offset_helper, buffer, FIT_POINTER_LOCATION)); /* Ensure pointer is below 4GiB and within 16MiB of 4GiB */ if (fit_pointer[1] != 0 || fit_pointer[0] < FIT_TABLE_LOWEST_ADDRESS) return NULL; table = rom_buffer_pointer(buffer, ptr_to_offset(offset_helper, buffer, *fit_pointer)); /* Check that the address field has the proper signature. */ if (strncmp((const char *)&table->header.address, FIT_HEADER_ADDRESS, sizeof(table->header.address))) return NULL; if (table->header.version != FIT_HEADER_VERSION) return NULL; if (fit_entry_type(&table->header) != FIT_TYPE_HEADER) return NULL; /* Assume that the FIT table only contains the header */ if (fit_entry_size_bytes(&table->header) != sizeof(struct fit_entry)) return NULL; return table; } static void update_fit_checksum(struct fit_table *fit) { int size_bytes; uint8_t *buffer; uint8_t result; int i; fit->header.checksum = 0; size_bytes = fit_entry_size_bytes(&fit->header); result = 0; buffer = (void *)fit; for (i = 0; i < size_bytes; i++) result += buffer[i]; fit->header.checksum = -result; } static void add_microcodde_entries(struct fit_table *fit, const struct cbfs_image *image, int num_mcus, struct microcode_entry *mcus, fit_offset_converter_t offset_helper) { int i; for (i = 0; i < num_mcus; i++) { struct fit_entry *entry = &fit->entries[i]; struct microcode_entry *mcu = &mcus[i]; entry->address = offset_to_ptr(offset_helper, &image->buffer, mcu->offset); fit_entry_update_size(entry, mcu->size); entry->version = FIT_MICROCODE_VERSION; entry->type_checksum_valid = FIT_TYPE_MICROCODE; entry->checksum = 0; fit_entry_add_size(&fit->header, sizeof(struct fit_entry)); } } static int fit_header(void *ptr, uint32_t *current_offset, uint32_t *file_length) { struct buffer buf; struct cbfs_file header; buf.data = ptr; buf.size = sizeof(header); cbfs_file_get_header(&buf, &header); *current_offset = header.offset; *file_length = header.len; return 0; } static int parse_microcode_blob(struct cbfs_image *image, struct cbfs_file *mcode_file, struct microcode_entry *mcus, int *total_mcus) { int num_mcus; uint32_t current_offset; uint32_t file_length; fit_header(mcode_file, ¤t_offset, &file_length); current_offset += (int)((char *)mcode_file - image->buffer.data); num_mcus = 0; while (file_length > sizeof(struct microcode_header)) { const struct microcode_header *mcu_header; mcu_header = rom_buffer_pointer(&image->buffer, current_offset); /* Quickly sanity check a prospective microcode update. */ if (mcu_header->total_size < sizeof(*mcu_header)) break; /* FIXME: Should the checksum be validated? */ mcus[num_mcus].offset = current_offset; mcus[num_mcus].size = mcu_header->total_size; /* Proceed to next payload. */ current_offset += mcus[num_mcus].size; file_length -= mcus[num_mcus].size; num_mcus++; /* Reached limit of FIT entries. */ if (num_mcus == *total_mcus) break; if (file_length < sizeof(struct microcode_header)) break; } /* Update how many microcode updates we found. */ *total_mcus = num_mcus; return 0; } int fit_update_table(struct buffer *bootblock, struct cbfs_image *image, const char *microcode_blob_name, int empty_entries, fit_offset_converter_t offset_fn) { struct fit_table *fit; struct cbfs_file *mcode_file; struct microcode_entry *mcus; int ret = 0; // struct rom_image image = { .rom = rom, .size = romsize, }; fit = locate_fit_table(offset_fn, bootblock); if (!fit) { ERROR("FIT not found.\n"); return 1; } mcode_file = cbfs_get_entry(image, microcode_blob_name); if (!mcode_file) { ERROR("File '%s' not found in CBFS.\n", microcode_blob_name); return 1; } mcus = malloc(sizeof(*mcus) * empty_entries); if (!mcus) { ERROR("Couldn't allocate memory for microcode update entries.\n"); return 1; } if (parse_microcode_blob(image, mcode_file, mcus, &empty_entries)) { ERROR("Couldn't parse microcode blob.\n"); ret = 1; goto out; } add_microcodde_entries(fit, image, empty_entries, mcus, offset_fn); update_fit_checksum(fit); out: free(mcus); return ret; }