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From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Thu, 28 Jul 2022 20:30:15 +0800
Message-ID: <CAAhV-H4vurz+-jwJm4SCQeaChLkXhrPFginpzNpYX6HkcD_xqA@mail.gmail.com>
Subject: Re: [PATCH 2/4] LoongArch: Support R_LARCH_SOP_PUSH_GPREL relocation
 type in kernel module
To:     Xi Ruoyao <xry111@xry111.site>
Cc:     loongarch@lists.linux.dev, LKML <linux-kernel@vger.kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Youling Tang <tangyouling@loongson.cn>,
        Jinyang He <hejinyang@loongson.cn>
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Hi, Ruoyao,

Missing V2 in the title?

Huacai

On Thu, Jul 28, 2022 at 7:59 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> This relocation type pushes the offset of the GOT entry for a symbol
> from the beginning of GOT into the relocation stack.  Our linker script
> has initialized an empty GOT, so we need to create a new GOT entry if
> there is no exist one for a symbol.
>
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>
> ---
>  arch/loongarch/kernel/module.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
> index 638427ff0d51..3ac4fbb5f109 100644
> --- a/arch/loongarch/kernel/module.c
> +++ b/arch/loongarch/kernel/module.c
> @@ -122,6 +122,16 @@ static int apply_r_larch_sop_push_plt_pcrel(struct module *mod, u32 *location, E
>         return apply_r_larch_sop_push_pcrel(mod, location, v, rela_stack, rela_stack_top, type);
>  }
>
> +static int apply_r_larch_sop_push_gprel(struct module *mod, u32 *location,
> +                       Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top,
> +                       unsigned int type)
> +{
> +       Elf_Addr got = module_emit_got_entry(mod, v);
> +       ptrdiff_t offset = (void *)got - (void *)mod->arch.got.shdr->sh_addr;
> +
> +       return rela_stack_push(offset, rela_stack, rela_stack_top);
> +}
> +
>  static int apply_r_larch_sop(struct module *mod, u32 *location, Elf_Addr v,
>                         s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
>  {
> @@ -306,6 +316,7 @@ static reloc_rela_handler reloc_rela_handlers[] = {
>         [R_LARCH_SOP_PUSH_PCREL]                             = apply_r_larch_sop_push_pcrel,
>         [R_LARCH_SOP_PUSH_ABSOLUTE]                          = apply_r_larch_sop_push_absolute,
>         [R_LARCH_SOP_PUSH_DUP]                               = apply_r_larch_sop_push_dup,
> +       [R_LARCH_SOP_PUSH_GPREL]                             = apply_r_larch_sop_push_gprel,
>         [R_LARCH_SOP_PUSH_PLT_PCREL]                         = apply_r_larch_sop_push_plt_pcrel,
>         [R_LARCH_SOP_SUB ... R_LARCH_SOP_IF_ELSE]            = apply_r_larch_sop,
>         [R_LARCH_SOP_POP_32_S_10_5 ... R_LARCH_SOP_POP_32_U] = apply_r_larch_sop_imm_field,
> --
> 2.37.0
>
>
>