Am 3. Juni 2021 04:17:56 MESZ schrieb Masami Hiramatsu
<masami.hirama...@linaro.org>:
>Because UEFI specification v2.9, 13.3 File System Format said "The
>file system supported by the Extensible Firmware Interface is based
>on the FAT file system.", the simple file system protocol might be
>better to support only FAT filesystem.
>
>There must be no problem from UEFI application to access only FAT
>because ESP must be formatted by FAT32 and the removable media is
>FAT12 or FAT16, according to the UEFI spec.
>
Does the UEFI spec forbid to access to other file systems?
Which problems were observed?
Best regards
Heinrich
>Reported-by: Kazuhiko Sakamoto <sakamoto.kazuh...@socionext.com>
>Signed-off-by: Masami Hiramatsu <masami.hirama...@linaro.org>
>---
> lib/efi_loader/efi_disk.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
>diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
>index 307d5d759b..f69ae6587f 100644
>--- a/lib/efi_loader/efi_disk.c
>+++ b/lib/efi_loader/efi_disk.c
>@@ -318,19 +318,25 @@ efi_fs_from_path(struct efi_device_path
>*full_path)
> }
>
> /**
>- * efi_fs_exists() - check if a partition bears a file system
>+ * efi_supported_fs_exists() - check if a partition bears a supported
>file system
> *
> * @desc: block device descriptor
> * @part: partition number
>- * Return: 1 if a file system exists on the partition
>+ * Return: 1 if a supported file system exists on the partition
> * 0 otherwise
> */
>-static int efi_fs_exists(struct blk_desc *desc, int part)
>+static int efi_supported_fs_exists(struct blk_desc *desc, int part)
> {
> if (fs_set_blk_dev_with_part(desc, part))
> return 0;
>
>- if (fs_get_type() == FS_TYPE_ANY)
>+ /*
>+ * Because UEFI specification v2.9, 13.3 File System Format said
>+ * "The file system supported by the Extensible Firmware Interface
>+ * is based on the FAT file system.", the simple file system protocol
>+ * should support only FAT filesystem.
>+ */
>+ if (fs_get_type() != FS_TYPE_FAT)
> return 0;
>
> fs_close();
>@@ -428,10 +434,10 @@ static efi_status_t efi_disk_add_dev(
>
> /*
> * On partitions or whole disks without partitions install the
>- * simple file system protocol if a file system is available.
>+ * simple file system protocol if a supported file system exists.
> */
> if ((part || desc->part_type == PART_TYPE_UNKNOWN) &&
>- efi_fs_exists(desc, part)) {
>+ efi_supported_fs_exists(desc, part)) {
> diskobj->volume = efi_simple_file_system(desc, part,
> diskobj->dp);
> ret = efi_add_protocol(&diskobj->header,
