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From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Wed, 1 Mar 2023 17:44:04 +0800
Message-ID: <CAAhV-H6Ed2PsOAmghM2NJB6fPbbdiq3ctF6ogjs6q+zCJykPAA@mail.gmail.com>
Subject: Re: [PATCH] efi/loongarch: Reintroduce efi_relocate_kernel() to
 relocate kernel
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Huacai Chen <chenhuacai@loongson.cn>, 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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Hi, Ard,

On Wed, Mar 1, 2023 at 5:17=E2=80=AFPM Ard Biesheuvel <ardb@kernel.org> wro=
te:
>
> 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 reintroduc=
e
> > efi_relocate_kernel() to relocate the core kernel.
> >
>
> Nice!
>
> I assume you will need to make a similar change for zboot?
zboot is always PIE (even before 6.3), so I suppose we don't need to
do anything?

Huacai
>
> > 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/fi=
rmware/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 *ima=
ge_addr,
> >                                  efi_loaded_image_t *image,
> >                                  efi_handle_t image_handle)
> >  {
> > -       int nr_pages =3D round_up(kernel_asize, EFI_ALLOC_ALIGN) / EFI_=
PAGE_SIZE;
> > -       efi_physical_addr_t kernel_addr =3D EFI_KIMG_PREFERRED_ADDRESS;
> >         efi_status_t status;
> > +       unsigned long kernel_addr =3D 0;
> >
> > -       /*
> > -        * Allocate space for the kernel image at the preferred offset.=
 This is
> > -        * the only location in memory from where we can execute the im=
age, so
> > -        * no point in falling back to another allocation.
> > -        */
> > -       status =3D efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
> > -                            EFI_LOADER_DATA, nr_pages, &kernel_addr);
> > -       if (status !=3D EFI_SUCCESS)
> > -               return status;
> > -
> > -       *image_addr =3D EFI_KIMG_PREFERRED_ADDRESS;
> > -       *image_size =3D kernel_asize;
> > +       kernel_addr =3D (unsigned long)&kernel_offset - kernel_offset;
> > +
> > +       status =3D efi_relocate_kernel(&kernel_addr, kernel_fsize, kern=
el_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 =3D kernel_addr;
> > +       *image_size =3D kernel_asize;
> >
> >         return status;
> >  }
> > --
> > 2.39.1
> >