boottime->efi_allocate_pages() returning EFI_NOT_FOUND

[Ben Schneider]

Hi, I'm trying to boot a compressed (via zboot) Linux kernel image
for aarch64 and running into an error I didn't expect.

To decompress itself, the kernel will run efi_zboot_entry() (found
in drivers/firmware/efi/libstub/zboot.c) which wants additional
memory so it asks for it via a call to the UEFI AllocatePages()
service.

U-Boot receives that request and runs efi_allocate_pages() (found
in lib/efi_loader/efi_memory.c). In its call, Linux is setting
type = EFI_ALLOCATE_ADDRESS, and memory_type = EFI_LOADER_CODE.

Based on some testing, it seems that the call to lmb_alloc_addr()
is not returning an address so efi_allocate_pages() returns
along this path:

addr = map_to_sysmem((void *)(uintptr_t)*memory);
addr = (u64)lmb_alloc_addr(addr, len, flags);
if (!addr)
        return EFI_NOT_FOUND;

It's not clear to me why I'm getting this error. I am using U-Boot
2025.04-rc3 configured with mvebu_espressobin_ultra-
8f3720_defconfig. I use Standard Boot (bootflow scan -b) to find
and load a systemd-boot EFI application which then tries to boot
the compressed Linux kernel. I am encountering this issue on a
real device with 1GB of memory. I would appreciate any guidance.

Thank you!

Ben