diff options
Diffstat (limited to 'src/security/vboot/vboot_loader.c')
| -rw-r--r-- | src/security/vboot/vboot_loader.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/src/security/vboot/vboot_loader.c b/src/security/vboot/vboot_loader.c new file mode 100644 index 0000000000..17ea0a9401 --- /dev/null +++ b/src/security/vboot/vboot_loader.c @@ -0,0 +1,158 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2015 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 <arch/early_variables.h> +#include <cbfs.h> +#include <cbmem.h> +#include <console/console.h> +#include <ec/google/chromeec/ec.h> +#include <rmodule.h> +#include <rules.h> +#include <string.h> +#include <security/vboot/misc.h> +#include <security/vboot/symbols.h> +#include <security/vboot/vboot_common.h> + +/* Ensure vboot configuration is valid: */ +_Static_assert(IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK) + + IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE) == 1, + "vboot must either start in bootblock or romstage (not both!)"); +_Static_assert(!IS_ENABLED(CONFIG_VBOOT_SEPARATE_VERSTAGE) || + IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK), + "stand-alone verstage must start in (i.e. after) bootblock"); +_Static_assert(!IS_ENABLED(CONFIG_VBOOT_RETURN_FROM_VERSTAGE) || + IS_ENABLED(CONFIG_VBOOT_SEPARATE_VERSTAGE), + "return from verstage only makes sense for separate verstages"); + +/* The stage loading code is compiled and entered from multiple stages. The + * helper functions below attempt to provide more clarity on when certain + * code should be called. */ + +static int verification_should_run(void) +{ + if (IS_ENABLED(CONFIG_VBOOT_SEPARATE_VERSTAGE)) + return ENV_VERSTAGE; + else if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE)) + return ENV_ROMSTAGE; + else if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK)) + return ENV_BOOTBLOCK; + else + die("impossible!"); +} + +static int verstage_should_load(void) +{ + if (IS_ENABLED(CONFIG_VBOOT_SEPARATE_VERSTAGE)) + return ENV_BOOTBLOCK; + else + return 0; +} + +static int vboot_executed CAR_GLOBAL; + +int vb2_logic_executed(void) +{ + /* If we are in a stage that would load the verstage or execute the + vboot logic directly, we store the answer in a global. */ + if (verstage_should_load() || verification_should_run()) + return car_get_var(vboot_executed); + + if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK)) { + /* All other stages are "after the bootblock" */ + return !ENV_BOOTBLOCK; + } else if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE)) { + /* Post-RAM stages are "after the romstage" */ +#ifdef __PRE_RAM__ + return 0; +#else + return 1; +#endif + } else { + die("impossible!"); + } +} + +static void vboot_prepare(void) +{ + if (verification_should_run()) { + /* Note: this path is not used for VBOOT_RETURN_FROM_VERSTAGE */ + verstage_main(); + car_set_var(vboot_executed, 1); + vb2_save_recovery_reason_vbnv(); + } else if (verstage_should_load()) { + struct cbfsf file; + struct prog verstage = + PROG_INIT(PROG_VERSTAGE, + CONFIG_CBFS_PREFIX "/verstage"); + + printk(BIOS_DEBUG, "VBOOT: Loading verstage.\n"); + + /* load verstage from RO */ + if (cbfs_boot_locate(&file, prog_name(&verstage), NULL)) + die("failed to load verstage"); + + cbfs_file_data(prog_rdev(&verstage), &file); + + if (cbfs_prog_stage_load(&verstage)) + die("failed to load verstage"); + + /* verify and select a slot */ + prog_run(&verstage); + + /* This is not actually possible to hit this condition at + * runtime, but this provides a hint to the compiler for dead + * code elimination below. */ + if (!IS_ENABLED(CONFIG_VBOOT_RETURN_FROM_VERSTAGE)) + return; + + car_set_var(vboot_executed, 1); + } + + /* + * Fill in vboot cbmem objects before moving to ramstage so all + * downstream users have access to vboot results. This path only + * applies to platforms employing VBOOT_STARTS_IN_ROMSTAGE because + * cbmem comes online prior to vboot verification taking place. For + * other platforms the vboot cbmem objects are initialized when + * cbmem comes online. + */ + if (ENV_ROMSTAGE && IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE)) { + vb2_store_selected_region(); + vboot_fill_handoff(); + } +} + +static int vboot_locate(struct cbfs_props *props) +{ + struct region selected_region; + + /* Don't honor vboot results until the vboot logic has run. */ + if (!vb2_logic_executed()) + return -1; + + if (vb2_get_selected_region(&selected_region)) + return -1; + + props->offset = region_offset(&selected_region); + props->size = region_sz(&selected_region); + + return 0; +} + +const struct cbfs_locator vboot_locator = { + .name = "VBOOT", + .prepare = vboot_prepare, + .locate = vboot_locate, +}; |