[RFC 12/14] efi_loader: return binary from efi_dp_from_lo()

[Heinrich Schuchardt]

On 4/28/24 15:28, Ilias Apalodimas wrote:
> Hi Heinrich
> 
> On Fri, 26 Apr 2024 at 17:14, Heinrich Schuchardt
> <heinrich.schuchardt at canonical.com> wrote:
>>
>> Up to now efi_dp_from_lo() only could return the initrd or fdt device-path.
>> Allow returning the binary device-path to.
> 
> Why do we need this?

In patch 14/14 I add this line:

+	dp = efi_get_dp_from_boot(NULL);

The binary path indicates the partition on which to search for the 
default dtb as indicated by $fdtfile.

I should have added an explanation in the commit message.

Best regards

Heinrich

> 
> Thanks
> /Ilias
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
>> ---
>>   lib/efi_loader/efi_device_path.c | 20 ++++++++++++--------
>>   1 file changed, 12 insertions(+), 8 deletions(-)
>>
>> diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
>> index 75fe95c9c1e..c8893f5626b 100644
>> --- a/lib/efi_loader/efi_device_path.c
>> +++ b/lib/efi_loader/efi_device_path.c
>> @@ -1140,17 +1140,18 @@ ssize_t efi_dp_check_length(const struct efi_device_path *dp,
>>   }
>>
>>   /**
>> - * efi_dp_from_lo() - Get the instance of a VenMedia node in a
>> - *                    multi-instance device path that matches
>> - *                    a specific GUID. This kind of device paths
>> - *                    is found in Boot#### options describing an
>> - *                    initrd location
>> + * efi_dp_from_lo() - get device-path from load option
>>    *
>> - * @lo:                EFI_LOAD_OPTION containing a valid device path
>> - * @guid:      guid to search for
>> + * The load options in U-Boot may contain multiple concatenated device-paths.
>> + * The first device-path indicates the EFI binary to execute. Subsequent
>> + * device-paths start with a VenMedia node where the GUID identifies the
>> + * function (initrd or fdt).
>> + *
>> + * @lo:                EFI load option containing a valid device path
>> + * @guid:      GUID identifying device-path or NULL for the EFI binary
>>    *
>>    * Return:
>> - * device path including the VenMedia node or NULL.
>> + * device path excluding the matched VenMedia node or NULL.
>>    * Caller must free the returned value.
>>    */
>>   struct
>> @@ -1161,6 +1162,9 @@ efi_device_path *efi_dp_from_lo(struct efi_load_option *lo,
>>          struct efi_device_path_vendor *vendor;
>>          int lo_len = lo->file_path_length;
>>
>> +       if (!guid)
>> +               return efi_dp_dup(fp);
>> +
>>          for (; lo_len >=  sizeof(struct efi_device_path);
>>               lo_len -= fp->length, fp = (void *)fp + fp->length) {
>>                  if (lo_len < 0 || efi_dp_check_length(fp, lo_len) < 0)
>> --
>> 2.43.0
>>