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Code Issues Releases Wiki Activity

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

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Arnd reports that commit

  9302c1bb8e ("efi/libstub: Rewrite file I/O routine")

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

  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: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200409130434.6736-8-ardb@kernel.org
This commit is contained in:
Ard Biesheuvel 2020-04-09 15:04:32 +02:00 committed by Ingo Molnar
parent 8b84769a7a
commit 464fb126d9
1 changed files with 14 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
drivers/firmware/efi/libstub/file.c
View file

@ -29,30 +29,31 @@
*/
#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,
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: ");
efi_char16_printk(filename_16);
efi_char16_printk(fi->filename);
efi_printk("\n");
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");
fh->close(fh);
@ -60,7 +61,7 @@ static efi_status_t efi_open_file(efi_file_protocol_t *volume,
}
*handle = fh;
*file_size = finfo.info.file_size;
*file_size = fi->info.file_size;
return EFI_SUCCESS;
}
@ -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)
break;
@ -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;