[PATCH v3 1/2] riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs

[Palmer Dabbelt]

On Tue, 14 Jul 2020 00:40:43 PDT (-0700), kernel at esmil.dk wrote:
> These are needed for the __jump_table in modules using
> static keys/jump-labels with the layout from
> HAVE_ARCH_JUMP_LABEL_RELATIVE on 64bit kernels.
>
> Signed-off-by: Emil Renner Berthing <kernel at esmil.dk>
> Reviewed-by: Björn Töpel <bjorn.topel at gmail.com>
> Tested-by: Björn Töpel <bjorn.topel at gmail.com>

These are on for-next.  Thanks!

> ---
> Tested on the HiFive Unleashed board.
>
> No changes since v2.
>
> This patch is new in v2. It fixes an error loading modules
> containing static keys found by Björn Töpel.
>
>  arch/riscv/kernel/module.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
> index 7191342c54da..104fba889cf7 100644
> --- a/arch/riscv/kernel/module.c
> +++ b/arch/riscv/kernel/module.c
> @@ -263,6 +263,13 @@ static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
>  	return 0;
>  }
>
> +static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
> +				    Elf_Addr v)
> +{
> +	*(u64 *)location += (u64)v;
> +	return 0;
> +}
> +
>  static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
>  				    Elf_Addr v)
>  {
> @@ -270,6 +277,13 @@ static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
>  	return 0;
>  }
>
> +static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
> +				    Elf_Addr v)
> +{
> +	*(u64 *)location -= (u64)v;
> +	return 0;
> +}
> +
>  static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
>  				Elf_Addr v) = {
>  	[R_RISCV_32]			= apply_r_riscv_32_rela,
> @@ -290,7 +304,9 @@ static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
>  	[R_RISCV_RELAX]			= apply_r_riscv_relax_rela,
>  	[R_RISCV_ALIGN]			= apply_r_riscv_align_rela,
>  	[R_RISCV_ADD32]			= apply_r_riscv_add32_rela,
> +	[R_RISCV_ADD64]			= apply_r_riscv_add64_rela,
>  	[R_RISCV_SUB32]			= apply_r_riscv_sub32_rela,
> +	[R_RISCV_SUB64]			= apply_r_riscv_sub64_rela,
>  };
>
>  int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,