blob: 4e81c6077188ede20f43800dc66ac28497142209 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* 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
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
#define MAX_FILENAME_SIZE 256
/*
* 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 on x86 because
* there are far more machines that require the workaround than those that
* break with it enabled.
*/
#define EFI_READ_CHUNK_SIZE SZ_1M
struct finfo {
efi_file_info_t info;
efi_char16_t filename[MAX_FILENAME_SIZE];
};
static efi_status_t efi_open_file(efi_file_protocol_t *volume,
struct finfo *fi,
efi_file_protocol_t **handle,
unsigned long *file_size)
{
efi_guid_t info_guid = EFI_FILE_INFO_ID;
efi_file_protocol_t *fh;
unsigned long info_sz;
efi_status_t status;
status = volume->open(volume, &fh, fi->filename, EFI_FILE_MODE_READ, 0);
if (status != EFI_SUCCESS) {
efi_err("Failed to open file: %ls\n", fi->filename);
return status;
}
info_sz = sizeof(struct finfo);
status = fh->get_info(fh, &info_guid, &info_sz, fi);
if (status != EFI_SUCCESS) {
efi_err("Failed to get file info\n");
fh->close(fh);
return status;
}
*handle = fh;
*file_size = fi->info.file_size;
return EFI_SUCCESS;
}
static efi_status_t efi_open_volume(efi_loaded_image_t *image,
efi_file_protocol_t **fh)
{
efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
efi_simple_file_system_protocol_t *io;
efi_status_t status;
status = efi_bs_call(handle_protocol, image->device_handle, &fs_proto,
(void **)&io);
if (status != EFI_SUCCESS) {
efi_err("Failed to handle fs_proto\n");
return status;
}
status = io->open_volume(io, fh);
if (status != EFI_SUCCESS)
efi_err("Failed to open volume\n");
return status;
}
static int find_file_option(const efi_char16_t *cmdline, int cmdline_len,
const efi_char16_t *prefix, int prefix_size,
efi_char16_t *result, int result_len)
{
int prefix_len = prefix_size / 2;
bool found = false;
int i;
for (i = prefix_len; i < cmdline_len; i++) {
if (!memcmp(&cmdline[i - prefix_len], prefix, prefix_size)) {
found = true;
break;
}
}
if (!found)
return 0;
/* Skip any leading slashes */
while (cmdline[i] == L'/' || cmdline[i] == L'\\')
i++;
while (--result_len > 0 && i < cmdline_len) {
efi_char16_t c = cmdline[i++];
if (c == L'\0' || c == L'\n' || c == L' ')
break;
else if (c == L'/')
/* Replace UNIX dir separators with EFI standard ones */
*result++ = L'\\';
else
*result++ = c;
}
*result = L'\0';
return i;
}
/*
* 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_loaded_image_t *image,
const efi_char16_t *optstr,
int optstr_size,
unsigned long soft_limit,
unsigned long hard_limit,
unsigned long *load_addr,
unsigned long *load_size)
{
const efi_char16_t *cmdline = image->load_options;
int cmdline_len = image->load_options_size;
unsigned long efi_chunk_size = ULONG_MAX;
efi_file_protocol_t *volume = NULL;
efi_file_protocol_t *file;
unsigned long alloc_addr;
unsigned long alloc_size;
efi_status_t status;
int offset;
if (!load_addr || !load_size)
return EFI_INVALID_PARAMETER;
efi_apply_loadoptions_quirk((const void **)&cmdline, &cmdline_len);
cmdline_len /= sizeof(*cmdline);
if (IS_ENABLED(CONFIG_X86) && !efi_nochunk)
efi_chunk_size = EFI_READ_CHUNK_SIZE;
alloc_addr = alloc_size = 0;
do {
struct finfo fi;
unsigned long size;
void *addr;
offset = find_file_option(cmdline, cmdline_len,
optstr, optstr_size,
fi.filename, ARRAY_SIZE(fi.filename));
if (!offset)
break;
cmdline += offset;
cmdline_len -= offset;
if (!volume) {
status = efi_open_volume(image, &volume);
if (status != EFI_SUCCESS)
return status;
}
status = efi_open_file(volume, &fi, &file, &size);
if (status != EFI_SUCCESS)
goto err_close_volume;
/*
* Check whether the existing allocation can contain the next
* file. This condition will also trigger naturally during the
* first (and typically only) iteration of the loop, given that
* alloc_size == 0 in that case.
*/
if (round_up(alloc_size + size, EFI_ALLOC_ALIGN) >
round_up(alloc_size, EFI_ALLOC_ALIGN)) {
unsigned long old_addr = alloc_addr;
status = EFI_OUT_OF_RESOURCES;
if (soft_limit < hard_limit)
status = efi_allocate_pages(alloc_size + size,
&alloc_addr,
soft_limit);
if (status == EFI_OUT_OF_RESOURCES)
status = efi_allocate_pages(alloc_size + size,
&alloc_addr,
hard_limit);
if (status != EFI_SUCCESS) {
efi_err("Failed to allocate memory for files\n");
goto err_close_file;
}
if (old_addr != 0) {
/*
* This is not the first time we've gone
* around this loop, and so we are loading
* multiple files that need to be concatenated
* and returned in a single buffer.
*/
memcpy((void *)alloc_addr, (void *)old_addr, alloc_size);
efi_free(alloc_size, old_addr);
}
}
addr = (void *)alloc_addr + alloc_size;
alloc_size += size;
while (size) {
unsigned long chunksize = min(size, efi_chunk_size);
status = file->read(file, &chunksize, addr);
if (status != EFI_SUCCESS) {
efi_err("Failed to read file\n");
goto err_close_file;
}
addr += chunksize;
size -= chunksize;
}
file->close(file);
} while (offset > 0);
*load_addr = alloc_addr;
*load_size = alloc_size;
if (volume)
volume->close(volume);
return EFI_SUCCESS;
err_close_file:
file->close(file);
err_close_volume:
volume->close(volume);
efi_free(alloc_size, alloc_addr);
return status;
}