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References: <20230301085545.2373646-1-chenhuacai@loongson.cn>
In-Reply-To: <20230301085545.2373646-1-chenhuacai@loongson.cn>
From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Wed, 1 Mar 2023 10:16:47 +0100
Message-ID: <CAMj1kXFybJ=snO5YG=6Uy2Qoi98b-6YTKX0Z9=1GPn=JMdxUiQ@mail.gmail.com>
Subject: Re: [PATCH] efi/loongarch: Reintroduce efi_relocate_kernel() to
 relocate kernel
To:     Huacai Chen <chenhuacai@loongson.cn>
Cc:     Huacai Chen <chenhuacai@kernel.org>, linux-efi@vger.kernel.org,
        loongarch@lists.linux.dev, Xuefeng Li <lixuefeng@loongson.cn>,
        Xuerui Wang <kernel@xen0n.name>, linux-kernel@vger.kernel.org,
        loongson-kernel@lists.loongnix.cn
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On Wed, 1 Mar 2023 at 09:55, Huacai Chen <chenhuacai@loongson.cn> wrote:
>
> Since Linux-6.3, LoongArch supports PIE kernel now, so let's reintroduce
> efi_relocate_kernel() to relocate the core kernel.
>

Nice!

I assume you will need to make a similar change for zboot?

> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  drivers/firmware/efi/libstub/loongarch-stub.c | 24 ++++++-------------
>  1 file changed, 7 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/loongarch-stub.c b/drivers/firmware/efi/libstub/loongarch-stub.c
> index eee7ed43cdfb..72c71ae201f0 100644
> --- a/drivers/firmware/efi/libstub/loongarch-stub.c
> +++ b/drivers/firmware/efi/libstub/loongarch-stub.c
> @@ -21,26 +21,16 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
>                                  efi_loaded_image_t *image,
>                                  efi_handle_t image_handle)
>  {
> -       int nr_pages = round_up(kernel_asize, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
> -       efi_physical_addr_t kernel_addr = EFI_KIMG_PREFERRED_ADDRESS;
>         efi_status_t status;
> +       unsigned long kernel_addr = 0;
>
> -       /*
> -        * Allocate space for the kernel image at the preferred offset. This is
> -        * the only location in memory from where we can execute the image, so
> -        * no point in falling back to another allocation.
> -        */
> -       status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
> -                            EFI_LOADER_DATA, nr_pages, &kernel_addr);
> -       if (status != EFI_SUCCESS)
> -               return status;
> -
> -       *image_addr = EFI_KIMG_PREFERRED_ADDRESS;
> -       *image_size = kernel_asize;
> +       kernel_addr = (unsigned long)&kernel_offset - kernel_offset;
> +
> +       status = efi_relocate_kernel(&kernel_addr, kernel_fsize, kernel_asize,
> +                    EFI_KIMG_PREFERRED_ADDRESS, efi_get_kimg_min_align(), 0x0);
>
> -       memcpy((void *)EFI_KIMG_PREFERRED_ADDRESS,
> -              (void *)&kernel_offset - kernel_offset,
> -              kernel_fsize);
> +       *image_addr = kernel_addr;
> +       *image_size = kernel_asize;
>
>         return status;
>  }
> --
> 2.39.1
>