Re: [PATCH 14/35] efi: Locate all block devices in the app

Hi Simon,

On Wed, Sep 08, 2021 at 08:14:30PM +0200, Heinrich Schuchardt wrote:

On 9/8/21 3:33 PM, Simon Glass wrote:

...

When starting the app, locate all block devices and make them available to U-Boot. This allows listing partitions and accessing files in filesystems.

EFI also has the concept of 'disks', meaning boot media. For now, this is not obviously useful in U-Boot, but add code to at least locate these. This can be expanded later as needed.

UEFI firmware handles with the EFI_BLOCK_IO_PROTOCOL for raw access to disks and partitions. It further provides the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL on these handles to access files on formatted media.

Do you want to implement "efifs" as a U-Boot's file system on top of SIMPLE_FILE_SYSTEM_PROTO? Just kidding.

I have one concern:

...

Signed-off-by: Simon Glass sjg@chromium.org

include/efi.h | 15 ++++++ include/efi_api.h | 15 ++++++ lib/efi/efi_app.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 149 insertions(+)

diff --git a/include/efi.h b/include/efi.h index 0ec5913ddd1..c0fddf7f6cd 100644 --- a/include/efi.h +++ b/include/efi.h @@ -529,4 +529,19 @@ void efi_putc(struct efi_priv *priv, const char ch); */ int efi_info_get(enum efi_entry_t type, void **datap, int *sizep);

+/**

• • efi_bind_block() - bind a new block device to an EFI device
• • Binds a new top-level EFI_MEDIA device as well as a child block device so
• • that the block device can be accessed in U-Boot.
• • The device can then be accessed using 'part list efi 0', 'fat ls efi 0:1',
• • for example, just like any other interface type.
• • @handle: handle of the controller on which this driver is installed
• • @blkio: block io protocol proxied by this driver
• • @return 0 if OK, -ve on error
• */

+int efi_bind_block(efi_handle_t handle, struct efi_block_io *blkio);

• #endif /* _LINUX_EFI_H */

diff --git a/include/efi_api.h b/include/efi_api.h index c8f959bb720..0e88b3e5dbe 100644 --- a/include/efi_api.h +++ b/include/efi_api.h @@ -1994,4 +1994,19 @@ struct efi_firmware_management_protocol { const u16 *package_version_name); };

+#define EFI_DISK_IO_PROTOCOL_GUID \

• EFI_GUID(0xce345171, 0xba0b, 0x11d2, 0x8e, 0x4f, \

•  0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
  

+struct efi_disk {

• u64 revision;
• efi_status_t (EFIAPI *read_disk)(struct efi_disk *this, u32 media_id,

• 			 u64 offset, efi_uintn_t buffer_size,
  

• 			 void *buffer);
  

• efi_status_t (EFIAPI *write_disk)(struct efi_disk *this, u32 media_id,

• 			  u64 offset, efi_uintn_t buffer_size,
  

• 			  void *buffer);
  

+};

• #endif

diff --git a/lib/efi/efi_app.c b/lib/efi/efi_app.c index f61665686c5..9ba48517422 100644 --- a/lib/efi/efi_app.c +++ b/lib/efi/efi_app.c @@ -21,6 +21,9 @@ #include <efi.h> #include <efi_api.h> #include <sysreset.h> +#include <dm/device-internal.h> +#include <dm/lists.h> +#include <dm/root.h>

DECLARE_GLOBAL_DATA_PTR;

@@ -46,6 +49,33 @@ int efi_info_get(enum efi_entry_t type, void **datap, int *sizep) return -ENOSYS; }

+/**

• • Create a block device so U-Boot can access an EFI device
• • @handle: EFI handle to bind
• • @blkio: block io protocol
• • Return: 0 = success
• */

+int efi_bind_block(efi_handle_t handle, struct efi_block_io *blkio) +{

• struct efi_media_plat plat;
• struct udevice *dev;
• char name[18];
• int ret;
• plat.handle = handle;
• plat.blkio = blkio;
• ret = device_bind(dm_root(), DM_DRIVER_GET(efi_media), "efi_media",

• 	  &plat, ofnode_null(), &dev);
  

• if (ret)

• return log_msg_ret("bind", ret);
  

• snprintf(name, sizeof(name), "efi_media_%x", dev_seq(dev));
• device_set_name(dev, name);
• return 0;

+}

• static efi_status_t setup_memory(struct efi_priv *priv) { struct efi_boot_services *boot = priv->boot;

@@ -105,6 +135,95 @@ static void free_memory(struct efi_priv *priv) global_data_ptr = NULL; }

+static int setup_disks(void) +{

• /* This is not fully implemented yet */
• return 0;
• efi_guid_t efi_disk_guid = EFI_DISK_IO_PROTOCOL_GUID;
• struct efi_boot_services *boot = efi_get_boot();
• struct efi_disk *disk;
• int ret;
• if (!boot)

• return log_msg_ret("sys", -ENOSYS);
  

• ret = boot->locate_protocol(&efi_disk_guid, NULL, (void **)&disk);
• if (ret)

• return log_msg_ret("prot", -ENOTSUPP);
  

• return 0;

+}

+static int setup_block(void) +{

• efi_guid_t efi_blkio_guid = EFI_BLOCK_IO_PROTOCOL_GUID;
• efi_guid_t efi_devpath_guid = EFI_DEVICE_PATH_PROTOCOL_GUID;
• struct efi_boot_services *boot = efi_get_boot();
• struct efi_block_io *blkio;
• struct efi_device_path device_path;
• efi_handle_t handle[100];
• efi_uintn_t buf_size;
• int num_handles;
• int ret, i;
• if (!boot)

• return log_msg_ret("sys", -ENOSYS);
  

• buf_size = sizeof(handle);
• ret = boot->locate_handle(BY_PROTOCOL, &efi_blkio_guid, NULL,

• 		  &buf_size, handle);
  

You could use LocateHandleBuffer() here which will allocate enough memory for all matching handles.

...

• if (ret)

• return log_msg_ret("loc", -ENOTSUPP);
  

• num_handles = buf_size / sizeof(efi_handle_t);
• log_info("Found %d EFI handles\n", num_handles);
• for (i = 0; i < num_handles; i++) {

• ret = boot->handle_protocol(handle[i], &efi_devpath_guid,
  

• 			    (void **)&device_path);
  

Why do you read the devicepath if you don't use it?

...

• if (ret) {
  

• 	log_warning("- devpath %d failed (ret=%d)\n", i, ret);
  

• 	continue;
  

• }
  

Here some analysis of devicepaths and installed protocols is missing to find out which of the handles represents a block device and which represents a partition:

If the last devicepath node is type 4 , Media Device Path with SubType 1 Hard Drive and the partition number is non-zero it is a partition.

If the devicepath without the last node relates to a handle with the EFI_BLOCK_IO_PROTOCOL, this also indicates that the current handle is for a partition.

Best regards

Heinrich

...

• ret = boot->handle_protocol(handle[i], &efi_blkio_guid,
  

• 			    (void **)&blkio);
  

• if (ret) {
  

• 	log_warning("- blkio %d failed (ret=%d)\n", i, ret);
  

• 	continue;
  

• }
  

• ret = efi_bind_block(handle[i], blkio);
  

Here you are trying to create a U-Boot block device for every UEFI block device (i.e.BLOCK_IO_PROTOCOL interface), but please remember that U-Boot UEFI has created UEFI block devices for all the existing U-Boot block devices at the initialization time.

So any physical disk may end up having one (original) U-Boot block device and another U-Boot block device rooted in UEFI object (and yet another U-Boot block device rooted in the second one and so on?).

-Takahiro Akashi

...

• if (ret) {
  

• 	log_warning("- blkio bind %d failed (ret=%d)\n", i, ret);
  

• 	continue;
  

• }
  

• }
• if (ret)

• return log_msg_ret("prot", -ENOTSUPP);
  

• return 0;

+}

+int dm_scan_other(bool pre_reloc_only) +{

• if (gd->flags & GD_FLG_RELOC) {

• int ret;
  

• /* Find all block devices and setup EFI devices for them */
  

• ret = setup_block();
  

• if (ret)
  

• 	return ret;
  

• /* Not needed at present, but could be useful one day? */
  

• ret = setup_disks();
  

• if (ret)
  

• 	return ret;
  

• }
• return 0;

+}

• /**
  • efi_main() - Start an EFI image