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![AKASHI Takahiro](/assets/img/avatar_default.png)
In this patch, helper functions for an load option variable (BootXXXX) are added: * efi_deserialize_load_option(): parse a string into load_option data (renamed from parse_load_option and exported) * efi_serialize_load_option(): convert load_option data into a string Those functions will be used to implement efishell command. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Alexander Graf <agraf@suse.de>
205 lines
4.8 KiB
C
205 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* EFI boot manager
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*
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* Copyright (c) 2017 Rob Clark
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*/
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#include <common.h>
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#include <charset.h>
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#include <malloc.h>
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#include <efi_loader.h>
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#include <asm/unaligned.h>
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static const struct efi_boot_services *bs;
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static const struct efi_runtime_services *rs;
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#define LOAD_OPTION_ACTIVE 0x00000001
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#define LOAD_OPTION_FORCE_RECONNECT 0x00000002
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#define LOAD_OPTION_HIDDEN 0x00000008
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/*
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* bootmgr implements the logic of trying to find a payload to boot
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* based on the BootOrder + BootXXXX variables, and then loading it.
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*
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* TODO detecting a special key held (f9?) and displaying a boot menu
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* like you would get on a PC would be clever.
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*
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* TODO if we had a way to write and persist variables after the OS
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* has started, we'd also want to check OsIndications to see if we
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* should do normal or recovery boot.
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*/
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/* Parse serialized data and transform it into efi_load_option structure */
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void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data)
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{
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lo->attributes = get_unaligned_le32(data);
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data += sizeof(u32);
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lo->file_path_length = get_unaligned_le16(data);
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data += sizeof(u16);
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/* FIXME */
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lo->label = (u16 *)data;
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data += (u16_strlen(lo->label) + 1) * sizeof(u16);
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/* FIXME */
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lo->file_path = (struct efi_device_path *)data;
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data += lo->file_path_length;
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lo->optional_data = data;
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}
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/*
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* Serialize efi_load_option structure into byte stream for BootXXXX.
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* Return a size of allocated data.
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*/
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unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
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{
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unsigned long label_len, option_len;
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unsigned long size;
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u8 *p;
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label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);
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option_len = strlen((char *)lo->optional_data);
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/* total size */
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size = sizeof(lo->attributes);
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size += sizeof(lo->file_path_length);
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size += label_len;
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size += lo->file_path_length;
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size += option_len + 1;
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p = malloc(size);
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if (!p)
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return 0;
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/* copy data */
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*data = p;
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memcpy(p, &lo->attributes, sizeof(lo->attributes));
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p += sizeof(lo->attributes);
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memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
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p += sizeof(lo->file_path_length);
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memcpy(p, lo->label, label_len);
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p += label_len;
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memcpy(p, lo->file_path, lo->file_path_length);
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p += lo->file_path_length;
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memcpy(p, lo->optional_data, option_len);
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p += option_len;
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*(char *)p = '\0';
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return size;
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}
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/* free() the result */
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static void *get_var(u16 *name, const efi_guid_t *vendor,
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efi_uintn_t *size)
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{
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efi_guid_t *v = (efi_guid_t *)vendor;
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efi_status_t ret;
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void *buf = NULL;
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*size = 0;
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EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
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if (ret == EFI_BUFFER_TOO_SMALL) {
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buf = malloc(*size);
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EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
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}
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if (ret != EFI_SUCCESS) {
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free(buf);
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*size = 0;
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return NULL;
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}
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return buf;
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}
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/*
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* Attempt to load load-option number 'n', returning device_path and file_path
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* if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
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* and that the specified file to boot exists.
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*/
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static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
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struct efi_device_path **file_path)
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{
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struct efi_load_option lo;
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u16 varname[] = L"Boot0000";
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u16 hexmap[] = L"0123456789ABCDEF";
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void *load_option, *image = NULL;
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efi_uintn_t size;
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varname[4] = hexmap[(n & 0xf000) >> 12];
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varname[5] = hexmap[(n & 0x0f00) >> 8];
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varname[6] = hexmap[(n & 0x00f0) >> 4];
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varname[7] = hexmap[(n & 0x000f) >> 0];
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load_option = get_var(varname, &efi_global_variable_guid, &size);
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if (!load_option)
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return NULL;
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efi_deserialize_load_option(&lo, load_option);
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if (lo.attributes & LOAD_OPTION_ACTIVE) {
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efi_status_t ret;
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debug("%s: trying to load \"%ls\" from %pD\n",
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__func__, lo.label, lo.file_path);
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ret = efi_load_image_from_path(lo.file_path, &image);
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if (ret != EFI_SUCCESS)
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goto error;
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printf("Booting: %ls\n", lo.label);
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efi_dp_split_file_path(lo.file_path, device_path, file_path);
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}
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error:
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free(load_option);
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return image;
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}
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/*
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* Attempt to load, in the order specified by BootOrder EFI variable, the
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* available load-options, finding and returning the first one that can
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* be loaded successfully.
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*/
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void *efi_bootmgr_load(struct efi_device_path **device_path,
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struct efi_device_path **file_path)
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{
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uint16_t *bootorder;
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efi_uintn_t size;
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void *image = NULL;
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int i, num;
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__efi_entry_check();
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bs = systab.boottime;
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rs = systab.runtime;
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bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
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if (!bootorder)
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goto error;
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num = size / sizeof(uint16_t);
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for (i = 0; i < num; i++) {
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debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]);
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image = try_load_entry(bootorder[i], device_path, file_path);
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if (image)
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break;
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}
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free(bootorder);
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error:
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__efi_exit_check();
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return image;
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}
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