Commit 464fb126 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Ingo Molnar

efi/libstub/file: Merge file name buffers to reduce stack usage

Arnd reports that commit

  9302c1bb ("efi/libstub: Rewrite file I/O routine")

reworks the file I/O routines in a way that triggers the following

  drivers/firmware/efi/libstub/file.c:240:1: warning: the frame size
            of 1200 bytes is larger than 1024 bytes [-Wframe-larger-than=]

We can work around this issue dropping an instance of efi_char16_t[256]
from the stack frame, and reusing the 'filename' field of the file info
struct that we use to obtain file information from EFI (which contains
the file name even though we already know it since we used it to open
the file in the first place)
Reported-by: default avatarArnd Bergmann <>
Signed-off-by: default avatarArd Biesheuvel <>
Signed-off-by: default avatarIngo Molnar <>
parent 8b84769a
......@@ -29,30 +29,31 @@
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,
efi_char16_t *filename_16,
struct finfo *fi,
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);
status = volume->open(volume, &fh, fi->filename, EFI_FILE_MODE_READ, 0);
if (status != EFI_SUCCESS) {
pr_efi_err("Failed to open file: ");
return status;
info_sz = sizeof(finfo);
status = fh->get_info(fh, &info_guid, &info_sz, &finfo);
info_sz = sizeof(struct finfo);
status = fh->get_info(fh, &info_guid, &info_sz, fi);
if (status != EFI_SUCCESS) {
pr_efi_err("Failed to get file info\n");
......@@ -60,7 +61,7 @@ static efi_status_t efi_open_file(efi_file_protocol_t *volume,
*handle = fh;
*file_size =;
*file_size = fi->info.file_size;
......@@ -146,13 +147,13 @@ static efi_status_t handle_cmdline_files(efi_loaded_image_t *image,
alloc_addr = alloc_size = 0;
do {
efi_char16_t filename[MAX_FILENAME_SIZE];
struct finfo fi;
unsigned long size;
void *addr;
offset = find_file_option(cmdline, cmdline_len,
optstr, optstr_size,
filename, ARRAY_SIZE(filename));
fi.filename, ARRAY_SIZE(fi.filename));
if (!offset)
......@@ -166,7 +167,7 @@ static efi_status_t handle_cmdline_files(efi_loaded_image_t *image,
return status;
status = efi_open_file(volume, filename, &file, &size);
status = efi_open_file(volume, &fi, &file, &size);
if (status != EFI_SUCCESS)
goto err_close_volume;
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