LoongArch: Add support for 64_PCREL relocation type

When build and update kernel with the latest upstream binutils and
loongson3_defconfig, module loader fails with:

  kmod: zsmalloc: Unknown relocation type 109
  kmod: fuse: Unknown relocation type 109
  kmod: fuse: Unknown relocation type 109
  kmod: radeon: Unknown relocation type 109
  kmod: nf_tables: Unknown relocation type 109
  kmod: nf_tables: Unknown relocation type 109

This is because the latest upstream binutils replaces a pair of ADD64
and SUB64 with 64_PCREL, so add support for 64_PCREL relocation type.

Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ecb802d02eeb
Cc: <stable@vger.kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/kernel/module.c

@@ -376,6 +376,15 @@ static int apply_r_larch_32_pcrel(struct module *mod, u32 *location, Elf_Addr v,
 	return 0;
 }
 
+static int apply_r_larch_64_pcrel(struct module *mod, u32 *location, Elf_Addr v,
+				  s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
+{
+	ptrdiff_t offset = (void *)v - (void *)location;
+
+	*(u64 *)location = offset;
+	return 0;
+}
+
 /*
  * reloc_handlers_rela() - Apply a particular relocation to a module
  * @mod: the module to apply the reloc to
@@ -406,6 +415,7 @@ static reloc_rela_handler reloc_rela_handlers[] = {
 	[R_LARCH_ADD32 ... R_LARCH_SUB64]		     = apply_r_larch_add_sub,
 	[R_LARCH_PCALA_HI20...R_LARCH_PCALA64_HI12]	     = apply_r_larch_pcala,
 	[R_LARCH_32_PCREL]				     = apply_r_larch_32_pcrel,
+	[R_LARCH_64_PCREL]				     = apply_r_larch_64_pcrel,
 };
 
 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,