[RFC PATCH v2 46/48] lmb: mark the EFI runtime memory regions as reserved

[Simon Glass]

Hi Sughosh,

On Thu, 4 Jul 2024 at 08:38, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
>
> Mark the EFI runtime memory region as reserved memory during board
> init so that it does not get allocated by the LMB module on subsequent
> memory requests.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> ---
> Changes since V1: New patch
>
>  lib/lmb.c | 41 ++++++++++++++++++++---------------------
>  1 file changed, 20 insertions(+), 21 deletions(-)

I see again that this is getting circular. Can you look at what is
actually allocated by EFI on init (i.e. before anything is booted)?

>
> diff --git a/lib/lmb.c b/lib/lmb.c
> index 387ec2ac65..6018f1de31 100644
> --- a/lib/lmb.c
> +++ b/lib/lmb.c
> @@ -19,6 +19,7 @@
>  #include <asm/global_data.h>
>  #include <asm/sections.h>
>  #include <linux/kernel.h>
> +#include <linux/sizes.h>
>
>  DECLARE_GLOBAL_DATA_PTR;
>
> @@ -212,33 +213,31 @@ void arch_lmb_reserve_generic(ulong sp, ulong end, ulong align)
>  /**
>   * efi_lmb_reserve() - add reservations for EFI memory
>   *
> - * Add reservations for all EFI memory areas that are not
> - * EFI_CONVENTIONAL_MEMORY.
> + * Add reservations for EFI runtime services memory
>   *
> - * Return:     0 on success, 1 on failure
> + * Return: None
>   */
> -static __maybe_unused int efi_lmb_reserve(void)
> +static __maybe_unused void efi_lmb_reserve(void)
>  {
> -       struct efi_mem_desc *memmap = NULL, *map;
> -       efi_uintn_t i, map_size = 0;
> -       efi_status_t ret;
> +       phys_addr_t runtime_start, runtime_end;
> +       unsigned long runtime_mask = EFI_PAGE_MASK;
>
> -       ret = efi_get_memory_map_alloc(&map_size, &memmap);
> -       if (ret != EFI_SUCCESS)
> -               return 1;
> +#if defined(__aarch64__)
> +       /*
> +        * Runtime Services must be 64KiB aligned according to the
> +        * "AArch64 Platforms" section in the UEFI spec (2.7+).
> +        */
>
> -       for (i = 0, map = memmap; i < map_size / sizeof(*map); ++map, ++i) {
> -               if (map->type != EFI_CONVENTIONAL_MEMORY) {
> -                       lmb_reserve_flags(map_to_sysmem((void *)(uintptr_t)
> -                                                       map->physical_start),
> -                                         map->num_pages * EFI_PAGE_SIZE,
> -                                         map->type == EFI_RESERVED_MEMORY_TYPE
> -                                             ? LMB_NOMAP : LMB_NONE);
> -               }
> -       }
> -       efi_free_pool(memmap);
> +       runtime_mask = SZ_64K - 1;
> +#endif
>
> -       return 0;
> +       /* Reserve the EFI runtime services memory */
> +       runtime_start = (uintptr_t)__efi_runtime_start & ~runtime_mask;
> +       runtime_end = (uintptr_t)__efi_runtime_stop;
> +       runtime_end = (runtime_end + runtime_mask) & ~runtime_mask;
> +
> +       lmb_reserve_flags(runtime_start, runtime_end - runtime_start,
> +                         LMB_NOOVERWRITE | LMB_NONOTIFY);
>  }
>
>  static void lmb_reserve_common(void *fdt_blob)
> --
> 2.34.1
>

Regards,
Simon