Re: Accessing RT services from OS

[Marvin H?user <Marvin.Haeuser@outlook.com>]

Good morning,

1.) Do you mean whether the OS exposes the Runtime Services? Windows and Linux expose the Variable Services (Linux even more, if I remember correctly) and macOS (not entirely sure about the latest version) the entire table via DeviceTree.
2.) Yes, you need to write a DXE Runtime Driver. One way to do it is install an UEFI Protocol and let the UEFI OS loader store its address (pay attention to allocate the structure from Runtime memory, update the pointers when going virtual and not use any Boot Services), another is to use the UEFI Configuration Table. Though remember that the OS still has hardware ownership, you might need to use Management Mode for your ideas. If you target Windows, I'm afraid software MMIs/ACPI or a shim for the RT Variable Services ("execute on variable write") are the only ways I know as you of course cannot alter the bootloader or access the System Table at runtime.

Regards,
Marvin.

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Ankit.Singh3@dell.com
> Sent: Tuesday, September 5, 2017 7:21 AM
> To: edk2-devel@lists.01.org
> Subject: [edk2] Accessing RT services from OS
> 
> Hi All,
> 
> Wanted to access RT services from OS.
> 	1.) Are there any already such exposed OS function or utilities ?
> 	2.) Can we plugin our own service/function to RT at run-time. ?
> 
> Regards,
> Ankit Singh
> 
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