linux-kernel - Re: [PATCH 1/1] efi/libstub: DRAM base calculation

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Date:   Mon, 7 Sep 2020 10:00:14 +0300
From:   Maxim Uvarov <maxim.uvarov@...aro.org>
To:     Heinrich Schuchardt <xypron.glpk@....de>
Cc:     Ard Biesheuvel <ardb@...nel.org>, Ingo Molnar <mingo@...nel.org>,
        Arvind Sankar <nivedita@...m.mit.edu>,
        linux-efi@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        Ilias Apalodimas <ilias.apalodimas@...aro.org>
Subject: Re: [PATCH 1/1] efi/libstub: DRAM base calculation

On Fri, 4 Sep 2020 at 18:50, Heinrich Schuchardt <xypron.glpk@....de> wrote:
>
> In the memory map the regions with the lowest addresses may be of type
> EFI_RESERVED_TYPE. The reserved areas may be discontinuous relative to the
> rest of the memory. So for calculating the maximum loading address for the
> device tree and the initial ramdisk image these reserved areas should not
> be taken into account.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@....de>
> ---
>  drivers/firmware/efi/libstub/efi-stub.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
> index c2484bf75c5d..13058ac75765 100644
> --- a/drivers/firmware/efi/libstub/efi-stub.c
> +++ b/drivers/firmware/efi/libstub/efi-stub.c
> @@ -106,7 +106,8 @@ static unsigned long get_dram_base(void)
>         map.map_end = map.map + map_size;
>
>         for_each_efi_memory_desc_in_map(&map, md) {
> -               if (md->attribute & EFI_MEMORY_WB) {
> +               if (md->attribute & EFI_MEMORY_WB &&
> +                   md->type != EFI_RESERVED_TYPE) {

shouldn't the type here be CONVENTIONAL?

>                         if (membase > md->phys_addr)
>                                 membase = md->phys_addr;
>                 }
> --
> 2.28.0
>