u-boot/lib/efi_loader/efi_bootmgr.c
Heinrich Schuchardt 0e18f584de efi_loader: LoadImage: always allocate new pages
If we want to properly unload images in Exit() the memory should always be
allocated in the same way. As we allocate memory when reading from file we
should do the same when the original image is in memory.

A further patch will be needed to free the memory when Exit() is called.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2019-02-16 15:42:20 +01:00

204 lines
4.8 KiB
C

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