[U-Boot] [PATCH 33/48] x86: Add relocation and link script for a 64-bit EFI application

Bin Meng bmeng.cn at gmail.com
Thu Jul 23 14:35:45 CEST 2015


Hi Simon,

On Wed, Jul 22, 2015 at 11:49 PM, Simon Glass <sjg at chromium.org> wrote:
> Add a link script and relocation code for building 64-bit EFI applications.

Nits: linker script

> This can be used for the EFI stub.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
>  arch/x86/cpu/efi/elf_x86_64_efi.lds | 87 +++++++++++++++++++++++++++++++++++
>  arch/x86/lib/reloc_x86_64.c         | 90 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 177 insertions(+)
>  create mode 100644 arch/x86/cpu/efi/elf_x86_64_efi.lds
>  create mode 100644 arch/x86/lib/reloc_x86_64.c
>
> diff --git a/arch/x86/cpu/efi/elf_x86_64_efi.lds b/arch/x86/cpu/efi/elf_x86_64_efi.lds
> new file mode 100644
> index 0000000..369f146
> --- /dev/null
> +++ b/arch/x86/cpu/efi/elf_x86_64_efi.lds
> @@ -0,0 +1,87 @@
> +/*
> + * U-Boot EFI link script
> + *

Ditto.

> + * SPDX-License-Identifier:    bsd-2-clause
> + *
> + * Modified from usr/lib32/elf_ia32_efi.lds in gnu-efi

I guess you want to say: usr/lib32/elf_x86_64_efi.lds

> + */
> +
> +#include <config.h>
> +
> +OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
> +OUTPUT_ARCH(i386:x86-64)
> +ENTRY(_start)
> +SECTIONS
> +{
> +       . = 0x0;

We don't have this line in the elf_ia32_efi.lds. Can this be removed.
Or we need add the same in the 32-bit lds.
(BTW: I checked gnu-efi, it has this line)

> +       ImageBase = .;

CamelCase

> +       .hash : { *(.hash) }    /* this MUST come first! */
> +       . = ALIGN(4096);
> +       .eh_frame : {
> +               *(.eh_frame)
> +       }
> +
> +       . = ALIGN(4096);
> +
> +       .text : {
> +               *(.text)
> +               *(.text.*)
> +               *(.gnu.linkonce.t.*)
> +       }
> +
> +       . = ALIGN(4096);
> +
> +       .reloc : {
> +               *(.reloc)
> +       }
> +
> +       . = ALIGN(4096);
> +
> +       .data : {
> +               *(.rodata*)
> +               *(.got.plt)
> +               *(.got)
> +               *(.data*)
> +               *(.sdata)
> +               /* the EFI loader doesn't seem to like a .bss section, so we stick
> +                * it all into .data: */
> +               *(.sbss)
> +               *(.scommon)
> +               *(.dynbss)
> +               *(.bss)
> +               *(COMMON)
> +               *(.rel.local)
> +
> +               /* U-Boot lists and device tree */
> +               . = ALIGN(8);
> +               KEEP(*(SORT(.u_boot_list*)));
> +               . = ALIGN(8);
> +               KEEP(*(.dtb*));
> +               /* Keep U-Boot payload */
> +               . = ALIGN(8);
> +               KEEP(*(.u_boot_bin.*));
> +       }
> +
> +       . = ALIGN(4096);
> +       .dynamic : { *(.dynamic) }
> +       . = ALIGN(4096);
> +
> +       .rela : {
> +               *(.rela.data*)
> +               *(.rela.got)
> +               *(.rela.stab)
> +       }
> +
> +       . = ALIGN(4096);
> +       .dynsym : { *(.dynsym) }
> +       . = ALIGN(4096);
> +       .dynstr : { *(.dynstr) }
> +       . = ALIGN(4096);
> +       .ignored.reloc : {
> +               *(.rela.reloc)
> +               *(.eh_frame)
> +               *(.note.GNU-stack)
> +       }
> +
> +       .comment 0 : { *(.comment) }
> +}
> diff --git a/arch/x86/lib/reloc_x86_64.c b/arch/x86/lib/reloc_x86_64.c
> new file mode 100644
> index 0000000..70a2b2a
> --- /dev/null
> +++ b/arch/x86/lib/reloc_x86_64.c
> @@ -0,0 +1,90 @@
> +/* reloc_x86_64.c - position independent x86_64 ELF shared object relocator
> +   Copyright (C) 1999 Hewlett-Packard Co.
> +       Contributed by David Mosberger <davidm at hpl.hp.com>.
> +   Copyright (C) 2005 Intel Co.
> +       Contributed by Fenghua Yu <fenghua.yu at intel.com>.
> +
> +    All rights reserved.
> +
> +    Redistribution and use in source and binary forms, with or without
> +    modification, are permitted provided that the following conditions
> +    are met:
> +
> +    * Redistributions of source code must retain the above copyright
> +      notice, this list of conditions and the following disclaimer.
> +    * Redistributions in binary form must reproduce the above
> +      copyright notice, this list of conditions and the following
> +      disclaimer in the documentation and/or other materials
> +      provided with the distribution.
> +    * Neither the name of Hewlett-Packard Co. nor the names of its
> +      contributors may be used to endorse or promote products derived
> +      from this software without specific prior written permission.
> +
> +    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
> +    CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
> +    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
> +    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
> +    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
> +    BE LIABLE FOR ANYDIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
> +    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
> +    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
> +    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> +    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
> +    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
> +    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> +    SUCH DAMAGE.

Please replace this with SPDX version.

> +*/
> +
> +#include <common.h>
> +#include <efi.h>
> +#include <elf.h>
> +#include <asm/elf.h>
> +
> +efi_status_t _relocate(long ldbase, Elf64_Dyn *dyn, efi_handle_t image,
> +                      struct efi_system_table *systab)
> +{
> +       long relsz = 0, relent = 0;
> +       struct elf64_rel *rel = 0;
> +       unsigned long *addr;
> +       int i;
> +
> +       for (i = 0; dyn[i].d_tag != DT_NULL; ++i) {
> +               switch (dyn[i].d_tag) {
> +               case DT_RELA:
> +                       rel = (struct elf64_rel *)
> +                               ((unsigned long)dyn[i].d_un.d_ptr + ldbase);
> +                       break;
> +               case DT_RELASZ:
> +                       relsz = dyn[i].d_un.d_val;
> +                       break;
> +               case DT_RELAENT:
> +                       relent = dyn[i].d_un.d_val;
> +                       break;
> +               default:
> +                       break;
> +               }
> +       }
> +
> +       if (!rel && relent == 0)
> +               return EFI_SUCCESS;
> +
> +       if (!rel || relent == 0)
> +               return EFI_LOAD_ERROR;
> +
> +       while (relsz > 0) {
> +               /* apply the relocs */
> +               switch (ELF64_R_TYPE(rel->r_info)) {
> +               case R_X86_64_NONE:
> +                       break;
> +               case R_X86_64_RELATIVE:
> +                       addr = (unsigned long *)(ldbase + rel->r_offset);
> +                       *addr += ldbase;
> +                       break;
> +               default:
> +                       break;
> +               }
> +               rel = (struct elf64_rel *)((char *)rel + relent);
> +               relsz -= relent;
> +       }

Nits: blank line

> +       return EFI_SUCCESS;
> +}
> --

Regards,
Bin


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