riscv: Support R_RISCV_ADD64 and R_RISCV_SUB64 relocs

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 <[e-mail]>
Reviewed-by: Björn Töpel <[e-mail]>
Tested-by: Björn Töpel <[e-mail]>
Signed-off-by: Palmer Dabbelt <[e-mail]>

arch/riscv/kernel/module.c

···
 	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)
 {
 	*(u32 *)location -= (u32)v;
+	return 0;
+}
+
+static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
+				    Elf_Addr v)
+{
+	*(u64 *)location -= (u64)v;
 	return 0;
 }
 
···
 	[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,