[PATCH v2 07/15] efi/libstub: Add generic arch callbacks for DRTM

[Jonathan Cameron]

On Fri,  2 Oct 2026 20:31:44 -0300
Jason Gunthorpe <jgg at nvidia.com> wrote:

> If the architecture supports an EFI stub launched version of DRTM, it
> can select the kconfig and provide the hooks under its architecture
> build.
> 
> Have the common code parse a drtm=enforce|auto|off kernel command line
> parameter to set the boot behavior. Support commas in the args list since
> there will be more options here down the road.
> 
> efi_drtm_prepare() is called before doing any decompression or image
> relocation. It should figure out if DRTM is supported, policy-permitted,
> and how much memory efi_drtm_get_extra_size() should return.
> 
> The image handling is revised to allocate extra_size at the end of
> the normal image. The architecture can use this to store any
> information needed for the DRTM flow. It is always contiguous with
> Image, which is a requirement of ARM's specification.
> 
> efi_drtm_prepare_launch() is called while still in EFI boot services after
> Image is fully prepared in its final location.
> 
> efi_drtm_launch() is called after exiting boot services and must
> jump into the kernel through the DRTM flow. If it returns, then the
> normal launch is tried (auto mode).
> 
> The extra_size is allocated directly after the Image. Handle the
> trivial zboot flow now, and vmlinux in the following patch.
> 
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>

Seems fine to me.  Some of the functions affected have annoyingly
complex flows already but this isn't obviously making things worse!

Reviewed-by: Jonathan Cameron <jonathan.cameron at oss.qualcomm.com>