[RFC 3/3] cmd: efidebug: handle booting from removable media
AKASHI Takahiro
takahiro.akashi at linaro.org
Wed Nov 10 07:24:33 CET 2021
On Tue, Nov 09, 2021 at 10:50:37AM +0100, Heinrich Schuchardt wrote:
> On 11/9/21 02:32, AKASHI Takahiro wrote:
> > Support for booting from removable media is now added to UEFI boot
> > manager. Here we should modify efidebug command in order to define
> > a proper "BootXXXX" variable.
> >
> > With this patch applied, you will be able to specify the boot order,
> > usb and scsi:
>
> I guess for a removable device this should work even if the device is not
> present. But currently:
>
> => efidebug boot add -b 1000 USB_present usb 0:1 EFI/BOOT/BOOTARM.EFI
> => efidebug boot add -b 1000 USB_not_present usb 1:1 EFI/BOOT/BOOTARM.EFI
> Cannot create device path for "usb 1:1"
# In the second, I don't expect you to specify the file path,
# "EFI/BOOT/BOOTARM.EFI", for removable media support.
Yes, I have been aware of this issue but it is not this-patch specific
but an existing issue as you clearly mentioned above.
> A media device path like:
>
> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/UsbClass(0x0,0x0,0x9,0x0,0x1)/UsbClass(0x781,0x5571,0x0,0x0,0x0)/HD(1,MBR,0x0c449046,0x800,0x800)
>
> is not very helpful because the next device that you insert may have a
> different location of the ESP partition.
>
> I think you should store
>
> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/UsbClass(0x0,0x0,0x9,0x0,0x1)/UsbClass(0x781,0x5571,0x0,0x0,0x0)
Apparently it is promising but actually not because
"UsbClass(0x781,0x5571,0x0,0x0,0x0)" contains Vendor ID and
Product ID which can only be retrieved from a real device attached
to the board.
I'm not yet sure where "UsbClass(0x0,0x0,0x9,0x0,0x1)" comes from.
"USB(X, Y)", where X is a parent_port_number and Y is a usb_interface,
would be a more appropriate candidate for this kind of device path,
but we don't utilise this form in the current implementation.
> and find the ESP on it at runtime.
I don't think the specification requires that the disk is an ESP
(at least explicitly).
> > => efidebug -b 1 SCSI scsi 0:1
> > => efidebug boot dump
> > Boot0001:
> > attributes: A-- (0x00000001)
> > label: SCSI
> > file_path: /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/Scsi(0,0)/
Contrary to USB, we use Scsi(0,0) for scsi devices but it is NOT identical
to U-Boot's scsi0 (in boot_targets).
> > HD(1,GPT,0ed48d12-1b4c-4e08-b3ee-decf20428036,0x800,0xa000)
> > data:
> > 00000000: 00 00
> > => efideubg -b 2 USB usb 0:1
>
> efidebug
OK
-Takahiro Akashi
> Best regards
>
> Heinrich
>
> > => efidebug boot order 2 1
> > => bootefi bootmgr
> >
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> > ---
> > cmd/efidebug.c | 46 ++++++++++++++++++++++++++++++++++++++++------
> > 1 file changed, 40 insertions(+), 6 deletions(-)
> >
> > diff --git a/cmd/efidebug.c b/cmd/efidebug.c
> > index a977ca9c72f5..aaf269cdf47d 100644
> > --- a/cmd/efidebug.c
> > +++ b/cmd/efidebug.c
> > @@ -933,6 +933,29 @@ out:
> > return initrd_dp;
> > }
> > +/**
> > + * count_arguments - count the number of arguments
> > + * @argc: Total number of arguments
> > + * @argv: Argument array
> > + * Return: Number of arguments
> > + *
> > + * Count the number of arguments for a given option, "-?"
> > + * Specifically if the first argument is not "-?", return 0;
> > + */
> > +static int count_arguments(int argc, char *const argv[])
> > +{
> > + int i;
> > +
> > + if (argv[0][0] != '-')
> > + return 0;
> > +
> > + for (i = 1; i < argc; i++)
> > + if (argv[i][0] == '-')
> > + break;
> > +
> > + return i;
> > +}
> > +
> > /**
> > * do_efi_boot_add() - set UEFI load option
> > *
> > @@ -945,7 +968,7 @@ out:
> > *
> > * Implement efidebug "boot add" sub-command. Create or change UEFI load option.
> > *
> > - * efidebug boot add -b <id> <label> <interface> <devnum>[:<part>] <file>
> > + * efidebug boot add -b <id> <label> <interface> <devnum>[:<part>] [<file>]
> > * -i <file> <interface2> <devnum2>[:<part>] <initrd>
> > * -s '<options>'
> > */
> > @@ -979,7 +1002,10 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
> > argv++; /* 'add' */
> > for (; argc > 0; argc--, argv++) {
> > if (!strcmp(argv[0], "-b")) {
> > - if (argc < 5 || lo.label) {
> > + int num_args;
> > +
> > + num_args = count_arguments(argc, argv);
> > + if (num_args < 5 || num_args > 6 || lo.label) {
> > r = CMD_RET_USAGE;
> > goto out;
> > }
> > @@ -1000,7 +1026,8 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
> > utf8_utf16_strncpy(&label, argv[2], label_len);
> > /* file path */
> > - ret = efi_dp_from_name(argv[3], argv[4], argv[5],
> > + ret = efi_dp_from_name(argv[3], argv[4],
> > + num_args == 5 ? "" : argv[5],
> > &device_path, &file_path);
> > if (ret != EFI_SUCCESS) {
> > printf("Cannot create device path for \"%s %s\"\n",
> > @@ -1008,10 +1035,16 @@ static int do_efi_boot_add(struct cmd_tbl *cmdtp, int flag,
> > r = CMD_RET_FAILURE;
> > goto out;
> > }
> > + /* if no file name is given, use device_path */
> > + if (num_args == 5) {
> > + efi_free_pool(file_path);
> > + file_path = device_path;
> > + device_path = NULL;
> > + }
> > fp_size += efi_dp_size(file_path) +
> > sizeof(struct efi_device_path);
> > - argc -= 5;
> > - argv += 5;
> > + argc -= num_args;
> > + argv += num_args;
> > } else if (!strcmp(argv[0], "-i")) {
> > if (argc < 3 || initrd_dp) {
> > r = CMD_RET_USAGE;
> > @@ -1078,7 +1111,8 @@ out:
> > free(data);
> > efi_free_pool(final_fp);
> > efi_free_pool(initrd_dp);
> > - efi_free_pool(device_path);
> > + if (device_path)
> > + efi_free_pool(device_path);
> > efi_free_pool(file_path);
> > free(lo.label);
> >
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