99 lines
2.3 KiB
C
99 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2020, Linaro Limited
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*/
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#define LOG_CATEGORY LOGC_EFI
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#include <common.h>
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#include <env.h>
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#include <malloc.h>
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#include <dm.h>
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#include <fs.h>
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#include <efi_load_initrd.h>
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#include <efi_loader.h>
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#include <efi_variable.h>
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/**
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* efi_create_current_boot_var() - Return Boot#### name were #### is replaced by
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* the value of BootCurrent
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*
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* @var_name: variable name
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* @var_name_size: size of var_name
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*
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* Return: Status code
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*/
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static efi_status_t efi_create_current_boot_var(u16 var_name[],
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size_t var_name_size)
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{
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efi_uintn_t boot_current_size;
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efi_status_t ret;
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u16 boot_current;
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u16 *pos;
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boot_current_size = sizeof(boot_current);
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ret = efi_get_variable_int(L"BootCurrent",
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&efi_global_variable_guid, NULL,
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&boot_current_size, &boot_current, NULL);
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if (ret != EFI_SUCCESS)
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goto out;
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pos = efi_create_indexed_name(var_name, var_name_size, "Boot",
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boot_current);
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if (!pos) {
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ret = EFI_OUT_OF_RESOURCES;
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goto out;
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}
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out:
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return ret;
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}
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/**
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* efi_get_dp_from_boot() - Retrieve and return a device path from an EFI
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* Boot### variable.
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* A boot option may contain an array of device paths.
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* We use a VenMedia() with a specific GUID to identify
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* the usage of the array members. This function is
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* used to extract a specific device path
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*
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* @guid: vendor GUID of the VenMedia() device path node identifying the
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* device path
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*
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* Return: device path or NULL. Caller must free the returned value
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*/
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struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid)
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{
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struct efi_device_path *file_path = NULL;
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struct efi_device_path *tmp = NULL;
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struct efi_load_option lo;
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void *var_value = NULL;
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efi_uintn_t size;
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efi_status_t ret;
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u16 var_name[16];
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ret = efi_create_current_boot_var(var_name, sizeof(var_name));
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if (ret != EFI_SUCCESS)
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return NULL;
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var_value = efi_get_var(var_name, &efi_global_variable_guid, &size);
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if (!var_value)
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return NULL;
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ret = efi_deserialize_load_option(&lo, var_value, &size);
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if (ret != EFI_SUCCESS)
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goto out;
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tmp = efi_dp_from_lo(&lo, &size, guid);
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if (!tmp)
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goto out;
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/* efi_dp_dup will just return NULL if efi_dp_next is NULL */
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file_path = efi_dp_dup(efi_dp_next(tmp));
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out:
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efi_free_pool(tmp);
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free(var_value);
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return file_path;
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}
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