[U-Boot] [PATCH 1/5] efi_loader: bootmgr: support BootNext and BootCurrent variable behavior

[Alexander Graf]

On 25.12.18 10:36, AKASHI Takahiro wrote:
> On Sun, Dec 23, 2018 at 03:03:51AM +0100, Alexander Graf wrote:
>>
>>
>> On 18.12.18 06:02, AKASHI Takahiro wrote:
>>> See UEFI v2.7, section 3.1.2 for details of the specification.
>>>
>>> With my efishell command[1], you can try as the following:
>>>   => efi boot add 1 SHELL ...
>>>   => efi boot add 2 HELLO ...
>>>   => efi boot order 1 2
>>>   => efi bootmgr
>>>      (starting SHELL ...)
>>>   => efi setvar BootNext =H0200
>>>   => efi bootmgr
>>>      (starting HELLO ...)
>>>   => efi dumpvar
>>>   <snip ...>
>>>   BootCurrent: {boot,run}(blob)
>>>   00000000:  02 00                    ..
>>>   BootOrder: {boot,run}(blob)
>>>   00000000:  01 00 02 00              ....
>>>
>>> Using "run -e" would be more human-friendly, though.
>>>
>>> [1] https://lists.denx.de/pipermail/u-boot/2018-November/346450.html
>>>
>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
>>> ---
>>>  lib/efi_loader/efi_bootmgr.c | 37 +++++++++++++++++++++++++++++++++++-
>>>  1 file changed, 36 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
>>> index a095df3f540b..a54ae28343ce 100644
>>> --- a/lib/efi_loader/efi_bootmgr.c
>>> +++ b/lib/efi_loader/efi_bootmgr.c
>>> @@ -145,11 +145,21 @@ static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
>>>  	efi_deserialize_load_option(&lo, load_option);
>>>  
>>>  	if (lo.attributes & LOAD_OPTION_ACTIVE) {
>>> +		u32 attributes;
>>>  		efi_status_t ret;
>>>  
>>>  		debug("%s: trying to load \"%ls\" from %pD\n",
>>>  		      __func__, lo.label, lo.file_path);
>>>  
>>> +		attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
>>> +			     EFI_VARIABLE_RUNTIME_ACCESS;
>>> +		size = sizeof(n);
>>> +		ret = rs->set_variable(L"BootCurrent",
>>> +				       (efi_guid_t *)&efi_global_variable_guid,
>>> +				       attributes, size, &n);
>>
>> Every call into UEFI land (rs->foo(), bs->foo(), etc) has to go via the
>> EFI_CALL() macro. Otherwise we may destroy the "gd" pointer on ARM.
> 
> OK, but let me make sure one thing:
> My efishell calls efi_* functions directly in some places as
> Not all the features can be implemented only with boot/runtime services.
> In those cases, we don't have to use EFI_CALL(), right?

If your "efishell" is a UEFI binary, you can directly call boot/runtime
services. If it runs as part of the U-Boot code base, every call to
boot/runtime service callbacks *must* go through EFI_CALL().


Alex