[U-Boot] efi_loader: runtime services implementation broken?

[Bin Meng]

Hi Alex,

On Tue, Jul 3, 2018 at 11:05 PM, Alexander Graf <agraf at suse.de> wrote:
> On 07/03/2018 04:56 PM, Bin Meng wrote:
>>
>> Hi Alex,
>>
>> On Tue, Jul 3, 2018 at 10:32 PM, Alexander Graf <agraf at suse.de> wrote:
>>>
>>> On 07/03/2018 04:24 PM, Bin Meng wrote:
>>>>
>>>> Hi Alex, Heinrich,
>>>>
>>>> At present not all interfaces in lib/efi_loader/efi_runtime.c are
>>>> declared as __efi_runtime. But only declaring those as __efi_runtime
>>>> is not enough. The data these interfaces use should be declared as
>>>> __efi_runtime_data too. More worse, any U-Boot APIs called by these
>>>> interfaces should be __efi_runtime and __efi_runtime_data
>>>> respectively.
>>>
>>>
>>> Correct. This is done for everything right now, no?
>>
>> For example, efi_set_virtual_address_map() is not declared as
>> __efi_runtime.
>
>
> Is that called post exit boot services on x86?

Yes, if you look at efi_runtime_services structure in
lib/efi_loader/efi_runtime.c, you can see
efi_set_virtual_address_map() is hooked up there, and all interfaces
in efi_runtime_services are supposed to be called by OS as their names
indicate, runtime not bootime.

>
>>
>>>> Eventually we need mark the RAM where the whole U-Boot image lives as
>>>> runtime service code and data and end up leaving whole U-Boot image in
>>>> the RAM after kernel boots?
>>>
>>>
>>> Why?
>>>
>> Unless we track down every APIs called by runtime services and mark
>> them correctly as __efi_runtime code/data.
>
>
> That's the idea, yes. The vector should be quite small as long as we don't
> actually implement / reuse drivers.

However this currently seems not to be the case ..

>
>>
>>>> Right now I am testing booting Linux on Intel Galileo with 'bootefi'
>>>> and kernel just hangs during the boot. Initial debugging shows that
>>>> kernel crashes when calling runtime service
>>>> efi_set_virtual_address_map().
>>>
>>>
>>> Can you please try with my efi-next branch? I added a few patches that
>>> allow
>>> gcc to put implicit data and code into the runtime section. Without
>>> those,
>>> you may get constant propagation into a the common .rodata segment for
>>> example.
>>>
>> Still the same.
>
>
> Ok, maybe the x86 efi stub does things different from the ARM one then.
>

maybe :(

Regards,
Bin