On 8/20/26 17:14, Bruno Banelli wrote:
> On Armada 7k/8k only a part of DRAM is mapped in U-Boot's MMU.
> arch/arm/mach-mvebu/armada8k/cpu.c maps 0..0x04000000 and
> 0x05400000..0x85400000 (plus MMIO), and arm64-common.c clamps
> board_get_usable_ram_top() to USABLE_RAM_SIZE (2 GiB) with the
> comment "Not all memory is mapped in the MMU". At the same time
> a8k_dram_init_banksize() advertises the whole DRAM in bi_dram[],
> adding a second bank at 4 GiB whenever more than 3 GiB is populated.
>
> Until commit e1b6822d6522 ("efi_memory: do not add RAM memory to the
> memory map") the EFI subsystem bridged that gap: efi_add_known_memory()
> reserved everything above gd->ram_top, as introduced by commit
> 7b78d6438a2b ("efi_loader: Reserve unaccessible memory"). EFI
> allocations are now backed by LMB, and LMB does not consider ram_top
> by default, so the first efi_allocate_pool() of the boot - from
> efi_init_early() -> efi_console_register() -> efi_create_event() -
> takes the highest free page and faults:
>
> Tested on a SolidRun MACCHIATObin (Armada 8040): without this change the
> abort reproduces both with 4 GiB of DRAM (far 0x13ffff000) and with 8 GiB
> (far 0x23ffff000), the faulting address tracking the top of the highest
> bank; with it, U-Boot reaches the prompt.
>
> LMB_LIMIT_DMA_BELOW_RAM_TOP, added by commit af4aad1f0a0b ("lmb:
> Optionally limit available memory to 4 GiB on limited systems"),
> reserves the memory above ram_top and addresses exactly this case. It
> is already enabled for ARCH_BCM283X and ARCH_ROCKCHIP; enable it for
> ARCH_MVEBU as well.
>
> Tested on a SolidRun MACCHIATObin (Armada 8040) with 4 GiB of DRAM,
> which reproduces the abort above without this change and reaches the
> prompt with it.
>
> Fixes: e1b6822d6522 ("efi_memory: do not add RAM memory to the memory map")
> Signed-off-by: Bruno Banelli <[email protected]>
Applied to u-boot-marvell/next
Thanks,
Stefan
