[PATCH 1/2] efi: Add ESRT to the EFI system table

[Heinrich Schuchardt]

On 2/8/21 11:18 PM, Heinrich Schuchardt wrote:
> On 2/8/21 1:52 PM, Jose Marinho wrote:
>> The ESRT is initialised during efi_init_objlist after
>> efi_initialize_system_table().
>>
>> The ESRT is initially created with size for 50 FW image entries.
>> The ESRT is resized when it runs out of space. Every resize adds 50
>> additional entries.
>> The ESRT is populated from information provided by FMP instances only.
>>
>> Signed-off-by: Jose Marinho<jose.marinho at arm.com>
>
>
> <josem> one limitation is, if any FMP instance is installed and then
> uninstalled during the same boottime flow, the ESRT entries will not be
> removed
> <josem> this limitation is because I cannot find a proper UEFI way to
> hook to a FMP protocol uninstall.
> <xypron> register an event with RegisterProtocolNotify().
> <xypron> EFI_CALL(efi_register_protocol_notify(...)) after exporting the
> function in /include/efi_loader
> <xypron> The event can be created with efi_create_event().


RegisterProtocolNotifiy() only tells you that a protocol is newly
installed, or reinstalled.

If you open the protocol with EFI_OPEN_PROTOCOL_BY_DRIVER, than
EFI_BOOT_SERVICES.UninstallProtocolInterface() will call
EFI_BOOT_SERVICES.DisconnectController() for the driver which will end
up in calling the Stop() function of the driver binding protocol.

Instead of using RegisterProtocolNotifiy() it would be better if the FMP
driver would call ConnectController() after installing its protocol.

This project is gone to show you all delights of EFI driver development.

Best regards

Heinrich