- 根目录:
- drivers
- firmware
- efi
- libstub
- efi-stub-helper.c
/*
* Helper functions used by the EFI stub on multiple
* architectures. This should be #included by the EFI stub
* implementation files.
*
* Copyright 2011 Intel Corporation; author Matt Fleming
*
* This file is part of the Linux kernel, and is made available
* under the terms of the GNU General Public License version 2.
*
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
/*
* Some firmware implementations have problems reading files in one go.
* A read chunk size of 1MB seems to work for most platforms.
*
* Unfortunately, reading files in chunks triggers *other* bugs on some
* platforms, so we provide a way to disable this workaround, which can
* be done by passing "efi=nochunk" on the EFI boot stub command line.
*
* If you experience issues with initrd images being corrupt it's worth
* trying efi=nochunk, but chunking is enabled by default because there
* are far more machines that require the workaround than those that
* break with it enabled.
*/
#define EFI_READ_CHUNK_SIZE (1024 * 1024)
static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
/*
* Allow the platform to override the allocation granularity: this allows
* systems that have the capability to run with a larger page size to deal
* with the allocations for initrd and fdt more efficiently.
*/
#ifndef EFI_ALLOC_ALIGN
#define EFI_ALLOC_ALIGN EFI_PAGE_SIZE
#endif
struct file_info {
efi_file_handle_t *handle;
u64 size;
};
void efi_printk(efi_system_table_t *sys_table_arg, char *str)
{
char *s8;
for (s8 = str; *s8; s8++) {
efi_char16_t ch[2] = { 0 };
ch[0] = *s8;
if (*s8 == '\n') {
efi_char16_t nl[2] = { '\r', 0 };
efi_char16_printk(sys_table_arg, nl);
}
efi_char16_printk(sys_table_arg, ch);
}
}
efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
efi_memory_desc_t **map,
unsigned long *map_size,
unsigned long *desc_size,
u32 *desc_ver,
unsigned long *key_ptr)
{
efi_memory_desc_t *m = NULL;
efi_status_t status;
unsigned long key;
u32 desc_version;
*map_size = sizeof(*m) * 32;
again:
/*
* Add an additional efi_memory_desc_t because we're doing an
* allocation which may be in a new descriptor region.
*/
*map_size += sizeof(*m);
status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
*map_size, (void **)&m);
if (status != EFI_SUCCESS)
goto fail;
*desc_size = 0;
key = 0;
status = efi_call_early(get_memory_map, map_size, m,
&key, desc_size, &desc_version);
if (status == EFI_BUFFER_TOO_SMALL) {
efi_call_early(free_pool, m);
goto again;
}
if (status != EFI_SUCCESS)
efi_call_early(free_pool, m);
if (key_ptr && status == EFI_SUCCESS)
*key_ptr = key;
if (desc_ver && status == EFI_SUCCESS)
*desc_ver = desc_version;
fail:
*map = m;
return status;
}
unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
{
efi_status_t status;
unsigned long map_size;
unsigned long membase = EFI_ERROR;
struct efi_memory_map map;
efi_memory_desc_t *md;
status = efi_get_memory_map(sys_table_arg, (efi_memory_desc_t **)&map.map,
&map_size, &map.desc_size, NULL, NULL);
if (status != EFI_SUCCESS)
return membase;
map.map_end = map.map + map_size;
for_each_efi_memory_desc(&map, md)
if (md->attribute & EFI_MEMORY_WB)
if (membase > md->phys_addr)
membase = md->phys_addr;
efi_call_early(free_pool, map.map);
return membase;
}
/*
* Allocate at the highest possible address that is not above 'max'.
*/
efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
unsigned long size, unsigned long align,
unsigned long *addr, unsigned long max)
{
unsigned long map_size, desc_size;
efi_memory_desc_t *map;
efi_status_t status;
unsigned long nr_pages;
u64 max_addr = 0;
int i;
status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
NULL, NULL);
if (status != EFI_SUCCESS)
goto fail;
/*
* Enforce minimum alignment that EFI requires when requesting
* a specific address. We are doing page-based allocations,
* so we must be aligned to a page.
*/
if (align < EFI_ALLOC_ALIGN)
align = EFI_ALLOC_ALIGN;
nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
again:
for (i = 0; i < map_size / desc_size; i++) {
efi_memory_desc_t *desc;
unsigned long m = (unsigned long)map;
u64 start, end;
desc = (efi_memory_desc_t *)(m + (i * desc_size));
if (desc->type != EFI_CONVENTIONAL_MEMORY)
continue;
if (desc->num_pages < nr_pages)
continue;
start = desc->phys_addr;
end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
if (end > max)
end = max;
if ((start + size) > end)
continue;
if (round_down(end - size, align) < start)
continue;
start = round_down(end - size, align);
/*
* Don't allocate at 0x0. It will confuse code that
* checks pointers against NULL.
*/
if (start == 0x0)
continue;
if (start > max_addr)
max_addr = start;
}
if (!max_addr)
status = EFI_NOT_FOUND;
else {
status = efi_call_early(allocate_pages,
EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
nr_pages, &max_addr);
if (status != EFI_SUCCESS) {
max = max_addr;
max_addr = 0;
goto again;
}
*addr = max_addr;
}
efi_call_early(free_pool, map);
fail:
return status;
}
/*
* Allocate at the lowest possible address.
*/
efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
unsigned long size, unsigned long align,
unsigned long *addr)
{
unsigned long map_size, desc_size;
efi_memory_desc_t *map;
efi_status_t status;
unsigned long nr_pages;
int i;
status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
NULL, NULL);
if (status != EFI_SUCCESS)
goto fail;
/*
* Enforce minimum alignment that EFI requires when requesting
* a specific address. We are doing page-based allocations,
* so we must be aligned to a page.
*/
if (align < EFI_ALLOC_ALIGN)
align = EFI_ALLOC_ALIGN;
nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
for (i = 0; i < map_size / desc_size; i++) {
efi_memory_desc_t *desc;
unsigned long m = (unsigned long)map;
u64 start, end;
desc = (efi_memory_desc_t *)(m + (i * desc_size));
if (desc->type != EFI_CONVENTIONAL_MEMORY)
continue;
if (desc->num_pages < nr_pages)
continue;
start = desc->phys_addr;
end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
/*
* Don't allocate at 0x0. It will confuse code that
* checks pointers against NULL. Skip the first 8
* bytes so we start at a nice even number.
*/
if (start == 0x0)
start += 8;
start = round_up(start, align);
if ((start + size) > end)
continue;
status = efi_call_early(allocate_pages,
EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
nr_pages, &start);
if (status == EFI_SUCCESS) {
*addr = start;
break;
}
}
if (i == map_size / desc_size)
status = EFI_NOT_FOUND;
efi_call_early(free_pool, map);
fail:
return status;
}
void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
unsigned long addr)
{
unsigned long nr_pages;
if (!size)
return;
nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
efi_call_early(free_pages, addr, nr_pages);
}
/*
* Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
* option, e.g. efi=nochunk.
*
* It should be noted that efi= is parsed in two very different
* environments, first in the early boot environment of the EFI boot
* stub, and subsequently during the kernel boot.
*/
efi_status_t efi_parse_options(char *cmdline)
{
char *str;
/*
* If no EFI parameters were specified on the cmdline we've got
* nothing to do.
*/
str = strstr(cmdline, "efi=");
if (!str)
return EFI_SUCCESS;
/* Skip ahead to first argument */
str += strlen("efi=");
/*
* Remember, because efi= is also used by the kernel we need to
* skip over arguments we don't understand.
*/
while (*str) {
if (!strncmp(str, "nochunk", 7)) {
str += strlen("nochunk");
__chunk_size = -1UL;
}
/* Group words together, delimited by "," */
while (*str && *str != ',')
str++;
if (*str == ',')
str++;
}
return EFI_SUCCESS;
}
/*
* Check the cmdline for a LILO-style file= arguments.
*
* We only support loading a file from the same filesystem as
* the kernel image.
*/
efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
efi_loaded_image_t *image,
char *cmd_line, char *option_string,
unsigned long max_addr,
unsigned long *load_addr,
unsigned long *load_size)
{
struct file_info *files;
unsigned long file_addr;
u64 file_size_total;
efi_file_handle_t *fh = NULL;
efi_status_t status;
int nr_files;
char *str;
int i, j, k;
file_addr = 0;
file_size_total = 0;
str = cmd_line;
j = 0; /* See close_handles */
if (!load_addr || !load_size)
return EFI_INVALID_PARAMETER;
*load_addr = 0;
*load_size = 0;
if (!str || !*str)
return EFI_SUCCESS;
for (nr_files = 0; *str; nr_files++) {
str = strstr(str, option_string);
if (!str)
break;
str += strlen(option_string);
/* Skip any leading slashes */
while (*str == '/' || *str == '\\')
str++;
while (*str && *str != ' ' && *str != '\n')
str++;
}
if (!nr_files)
return EFI_SUCCESS;
status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
nr_files * sizeof(*files), (void **)&files);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
goto fail;
}
str = cmd_line;
for (i = 0; i < nr_files; i++) {
struct file_info *file;
efi_char16_t filename_16[256];
efi_char16_t *p;
str = strstr(str, option_string);
if (!str)
break;
str += strlen(option_string);
file = &files[i];
p = filename_16;
/* Skip any leading slashes */
while (*str == '/' || *str == '\\')
str++;
while (*str && *str != ' ' && *str != '\n') {
if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
break;
if (*str == '/') {
*p++ = '\\';
str++;
} else {
*p++ = *str++;
}
}
*p = '\0';
/* Only open the volume once. */
if (!i) {
status = efi_open_volume(sys_table_arg, image,
(void **)&fh);
if (status != EFI_SUCCESS)
goto free_files;
}
status = efi_file_size(sys_table_arg, fh, filename_16,
(void **)&file->handle, &file->size);
if (status != EFI_SUCCESS)
goto close_handles;
file_size_total += file->size;
}
if (file_size_total) {
unsigned long addr;
/*
* Multiple files need to be at consecutive addresses in memory,
* so allocate enough memory for all the files. This is used
* for loading multiple files.
*/
status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
&file_addr, max_addr);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
goto close_handles;
}
/* We've run out of free low memory. */
if (file_addr > max_addr) {
pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
status = EFI_INVALID_PARAMETER;
goto free_file_total;
}
addr = file_addr;
for (j = 0; j < nr_files; j++) {
unsigned long size;
size = files[j].size;
while (size) {
unsigned long chunksize;
if (size > __chunk_size)
chunksize = __chunk_size;
else
chunksize = size;
status = efi_file_read(files[j].handle,
&chunksize,
(void *)addr);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table_arg, "Failed to read file\n");
goto free_file_total;
}
addr += chunksize;
size -= chunksize;
}
efi_file_close(files[j].handle);
}
}
efi_call_early(free_pool, files);
*load_addr = file_addr;
*load_size = file_size_total;
return status;
free_file_total:
efi_free(sys_table_arg, file_size_total, file_addr);
close_handles:
for (k = j; k < i; k++)
efi_file_close(files[k].handle);
free_files:
efi_call_early(free_pool, files);
fail:
*load_addr = 0;
*load_size = 0;
return status;
}
/*
* Relocate a kernel image, either compressed or uncompressed.
* In the ARM64 case, all kernel images are currently
* uncompressed, and as such when we relocate it we need to
* allocate additional space for the BSS segment. Any low
* memory that this function should avoid needs to be
* unavailable in the EFI memory map, as if the preferred
* address is not available the lowest available address will
* be used.
*/
efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
unsigned long *image_addr,
unsigned long image_size,
unsigned long alloc_size,
unsigned long preferred_addr,
unsigned long alignment)
{
unsigned long cur_image_addr;
unsigned long new_addr = 0;
efi_status_t status;
unsigned long nr_pages;
efi_physical_addr_t efi_addr = preferred_addr;
if (!image_addr || !image_size || !alloc_size)
return EFI_INVALID_PARAMETER;
if (alloc_size < image_size)
return EFI_INVALID_PARAMETER;
cur_image_addr = *image_addr;
/*
* The EFI firmware loader could have placed the kernel image
* anywhere in memory, but the kernel has restrictions on the
* max physical address it can run at. Some architectures
* also have a prefered address, so first try to relocate
* to the preferred address. If that fails, allocate as low
* as possible while respecting the required alignment.
*/
nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
status = efi_call_early(allocate_pages,
EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
nr_pages, &efi_addr);
new_addr = efi_addr;
/*
* If preferred address allocation failed allocate as low as
* possible.
*/
if (status != EFI_SUCCESS) {
status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
&new_addr);
}
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
return status;
}
/*
* We know source/dest won't overlap since both memory ranges
* have been allocated by UEFI, so we can safely use memcpy.
*/
memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
/* Return the new address of the relocated image. */
*image_addr = new_addr;
return status;
}
/*
* Get the number of UTF-8 bytes corresponding to an UTF-16 character.
* This overestimates for surrogates, but that is okay.
*/
static int efi_utf8_bytes(u16 c)
{
return 1 + (c >= 0x80) + (c >= 0x800);
}
/*
* Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
*/
static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
{
unsigned int c;
while (n--) {
c = *src++;
if (n && c >= 0xd800 && c <= 0xdbff &&
*src >= 0xdc00 && *src <= 0xdfff) {
c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
src++;
n--;
}
if (c >= 0xd800 && c <= 0xdfff)
c = 0xfffd; /* Unmatched surrogate */
if (c < 0x80) {
*dst++ = c;
continue;
}
if (c < 0x800) {
*dst++ = 0xc0 + (c >> 6);
goto t1;
}
if (c < 0x10000) {
*dst++ = 0xe0 + (c >> 12);
goto t2;
}
*dst++ = 0xf0 + (c >> 18);
*dst++ = 0x80 + ((c >> 12) & 0x3f);
t2:
*dst++ = 0x80 + ((c >> 6) & 0x3f);
t1:
*dst++ = 0x80 + (c & 0x3f);
}
return dst;
}
/*
* Convert the unicode UEFI command line to ASCII to pass to kernel.
* Size of memory allocated return in *cmd_line_len.
* Returns NULL on error.
*/
char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
efi_loaded_image_t *image,
int *cmd_line_len)
{
const u16 *s2;
u8 *s1 = NULL;
unsigned long cmdline_addr = 0;
int load_options_chars = image->load_options_size / 2; /* UTF-16 */
const u16 *options = image->load_options;
int options_bytes = 0; /* UTF-8 bytes */
int options_chars = 0; /* UTF-16 chars */
efi_status_t status;
u16 zero = 0;
if (options) {
s2 = options;
while (*s2 && *s2 != '\n'
&& options_chars < load_options_chars) {
options_bytes += efi_utf8_bytes(*s2++);
options_chars++;
}
}
if (!options_chars) {
/* No command line options, so return empty string*/
options = &zero;
}
options_bytes++; /* NUL termination */
status = efi_low_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr);
if (status != EFI_SUCCESS)
return NULL;
s1 = (u8 *)cmdline_addr;
s2 = (const u16 *)options;
s1 = efi_utf16_to_utf8(s1, s2, options_chars);
*s1 = '\0';
*cmd_line_len = options_bytes;
return (char *)cmdline_addr;
}