diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/file.c')
| -rw-r--r-- | drivers/firmware/efi/libstub/file.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/file.c b/drivers/firmware/efi/libstub/file.c new file mode 100644 index 000000000000..d4c7e5f59d2c --- /dev/null +++ b/drivers/firmware/efi/libstub/file.c @@ -0,0 +1,258 @@ +// 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 + +static efi_status_t efi_open_file(efi_file_protocol_t *volume, + efi_char16_t *filename_16, + efi_file_protocol_t **handle, + unsigned long *file_size) +{ + struct { + efi_file_info_t info; + efi_char16_t filename[MAX_FILENAME_SIZE]; + } finfo; + 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, filename_16, EFI_FILE_MODE_READ, 0); + if (status != EFI_SUCCESS) { + pr_efi_err("Failed to open file: "); + efi_char16_printk(filename_16); + efi_printk("\n"); + return status; + } + + info_sz = sizeof(finfo); + status = fh->get_info(fh, &info_guid, &info_sz, &finfo); + if (status != EFI_SUCCESS) { + pr_efi_err("Failed to get file info\n"); + fh->close(fh); + return status; + } + + *handle = fh; + *file_size = finfo.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) { + pr_efi_err("Failed to handle fs_proto\n"); + return status; + } + + status = io->open_volume(io, fh); + if (status != EFI_SUCCESS) + pr_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; + + while (--result_len > 0 && i < cmdline_len) { + if (cmdline[i] == L'\0' || + cmdline[i] == L'\n' || + cmdline[i] == L' ') + break; + *result++ = cmdline[i++]; + } + *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. + */ +static 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 / 2; + 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; + + if (IS_ENABLED(CONFIG_X86) && !nochunk()) + efi_chunk_size = EFI_READ_CHUNK_SIZE; + + alloc_addr = alloc_size = 0; + do { + efi_char16_t filename[MAX_FILENAME_SIZE]; + unsigned long size; + void *addr; + + offset = find_file_option(cmdline, cmdline_len, + optstr, optstr_size, + filename, ARRAY_SIZE(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, filename, &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) { + pr_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) { + pr_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; +} + +efi_status_t efi_load_dtb(efi_loaded_image_t *image, + unsigned long *load_addr, + unsigned long *load_size) +{ + return handle_cmdline_files(image, L"dtb=", sizeof(L"dtb=") - 2, + ULONG_MAX, ULONG_MAX, load_addr, load_size); +} + +efi_status_t efi_load_initrd(efi_loaded_image_t *image, + unsigned long *load_addr, + unsigned long *load_size, + unsigned long soft_limit, + unsigned long hard_limit) +{ + return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2, + soft_limit, hard_limit, load_addr, load_size); +} |