[PATCH] Revert "efi_memory: do not add U-Boot memory to the memory map"

[Sughosh Ganu]

On Tue, 12 Nov 2024 at 18:48, Simon Glass <sjg at chromium.org> wrote:
>
> A bisect of Ubuntu 2022.04 boot-failure on qemu-x86_64 resulted in this
> patch. I am not sure how to investigate it.
>
> The boot hangs at some point during booting of the install image, before
> the Ubuntu logo appears.
>
> I will sent a series with a script showing how it is run.
>
> This reverts commit a68c9ac5d8afc51c619c5d3e865fcf147bea90cb.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---

This seems to be an issue specific to the x86 architecture. The
installation works on arm64 and riscv (confirmed by Heinrich)
architectures. I checked the output of the EFI memory map with the
above commit against the master branch, and the only difference is
that with this revert, the EFI memory map has the u-boot memory region
marked as EFI_BOOT_SERVICES_CODE, whereas without this commit, that
region is marked as reserved. I need to look into this in more detail,
but it would seem like the x86 kernel (or some efi stub code ?) is
expecting some region of memory marked as EFI_BOOT_SERVICES_CODE,
which is not the case for other architectures.

-sughosh

>
>  lib/efi_loader/efi_memory.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
> index d2f5d563f2a..c7400ec9854 100644
> --- a/lib/efi_loader/efi_memory.c
> +++ b/lib/efi_loader/efi_memory.c
> @@ -809,6 +809,16 @@ static void add_u_boot_and_runtime(void)
>  {
>         unsigned long runtime_start, runtime_end, runtime_pages;
>         unsigned long runtime_mask = EFI_PAGE_MASK;
> +       unsigned long uboot_start, uboot_pages;
> +       unsigned long uboot_stack_size = CONFIG_STACK_SIZE;
> +
> +       /* Add U-Boot */
> +       uboot_start = ((uintptr_t)map_sysmem(gd->start_addr_sp, 0) -
> +                      uboot_stack_size) & ~EFI_PAGE_MASK;
> +       uboot_pages = ((uintptr_t)map_sysmem(gd->ram_top - 1, 0) -
> +                      uboot_start + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT;
> +       efi_add_memory_map_pg(uboot_start, uboot_pages, EFI_BOOT_SERVICES_CODE,
> +                             false);
>
>  #if defined(__aarch64__)
>         /*
> --
> 2.34.1
>