1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/file.c b/drivers/firmware/efi/libstub/file.c
new file mode 100644
index 000000000..f756c6139
--- /dev/null
+++ b/drivers/firmware/efi/libstub/file.c
@@ -0,0 +1,271 @@
+// 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)
+{
+	struct efi_vendor_dev_path *dp = image->file_path;
+	efi_guid_t li_proto = LOADED_IMAGE_PROTOCOL_GUID;
+	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
+	efi_simple_file_system_protocol_t *io;
+	efi_status_t status;
+
+	// If we are using EFI zboot, we should look for the file system
+	// protocol on the parent image's handle instead
+	if (IS_ENABLED(CONFIG_EFI_ZBOOT) &&
+	    image->parent_handle != NULL &&
+	    dp != NULL &&
+	    dp->header.type == EFI_DEV_MEDIA &&
+	    dp->header.sub_type == EFI_DEV_MEDIA_VENDOR &&
+	    !efi_guidcmp(dp->vendorguid, LINUX_EFI_ZBOOT_MEDIA_GUID)) {
+		status = efi_bs_call(handle_protocol, image->parent_handle,
+				     &li_proto, (void *)&image);
+		if (status != EFI_SUCCESS) {
+			efi_err("Failed to locate parent image handle\n");
+			return 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 (i < cmdline_len && (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;
+	u32 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);
+
+	if (*load_size == 0)
+		return EFI_NOT_READY;
+	return EFI_SUCCESS;
+
+err_close_file:
+	file->close(file);
+
+err_close_volume:
+	volume->close(volume);
+	efi_free(alloc_size, alloc_addr);
+	return status;
+}