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path: root/drivers/firmware/efi/libstub/file.c
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Diffstat (limited to 'drivers/firmware/efi/libstub/file.c')
-rw-r--r--drivers/firmware/efi/libstub/file.c258
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);
+}