[PATCH 14/35] efi: Locate all block devices in the app
AKASHI Takahiro
takahiro.akashi at linaro.org
Thu Sep 9 03:11:40 CEST 2021
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 at 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
> > *
> >
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