efi_loader: replace a u16_strdup with alloc + memcpy

Heinrich reports that on RISC-V unaligned access is emulated by OpenSBI
which is very slow.  Performance wise it's better if we skip the calls
to u16_strdup() -- which in turn calls u16_strsize() and just allocate/copy the
memory directly.  The access to dp.length may still be unaligned, but that's
way less than what u16_strsize() would do

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Use malloc() instead of calloc().
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
This commit is contained in:
Ilias Apalodimas 2022-11-11 20:04:31 +02:00 committed by Heinrich Schuchardt
parent 64012e0c52
commit a930d69baa

View File

@ -1137,6 +1137,7 @@ struct efi_file_handle *efi_file_from_path(struct efi_device_path *fp)
container_of(fp, struct efi_device_path_file_path, dp);
struct efi_file_handle *f2;
u16 *filename;
size_t filename_sz;
if (!EFI_DP_TYPE(fp, MEDIA_DEVICE, FILE_PATH)) {
printf("bad file path!\n");
@ -1149,9 +1150,14 @@ struct efi_file_handle *efi_file_from_path(struct efi_device_path *fp)
* protocol member functions to be aligned. So memcpy it
* unconditionally
*/
filename = u16_strdup(fdp->str);
if (fdp->dp.length <= offsetof(struct efi_device_path_file_path, str))
return NULL;
filename_sz = fdp->dp.length -
offsetof(struct efi_device_path_file_path, str);
filename = malloc(filename_sz);
if (!filename)
return NULL;
memcpy(filename, fdp->str, filename_sz);
EFI_CALL(ret = f->open(f, &f2, filename,
EFI_FILE_MODE_READ, 0));
free(filename);