[PATCH v1 2/3] LoongArch: Add support for 32_PCREL relocation type

[Tiezhu Yang]

When build and update kernel with the latest upstream binutils and
loongson3_defconfig, it can not start the system, the serial console
shows "You are in emergency mode", there are more info like this:

  kmod: zsmalloc: Unsupport relocation type 99, please add its support.
  kmod: fuse: Unsupport relocation type 99, please add its support.
  kmod: ipmi_msghandler: Unsupport relocation type 99, please add its support.
  kmod: ipmi_msghandler: Unsupport relocation type 99, please add its support.
  kmod: pstore: Unsupport relocation type 99, please add its support.
  kmod: drm_display_helper: Unsupport relocation type 99, please add its support.
  kmod: drm_display_helper: Unsupport relocation type 99, please add its support.
  kmod: drm_display_helper: Unsupport relocation type 99, please add its support.
  kmod: fuse: Unsupport relocation type 99, please add its support.
  kmod: fat: Unsupport relocation type 99, please add its support.

This is because the latest upstream binutils replaces a pair of ADD32
and SUB32 with 32_PCREL, so add support for 32_PCREL relocation type.

Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ecb802d02eeb
Co-developed-by: Youling Tang <tangyouling@xxxxxxxxxxx>
Signed-off-by: Youling Tang <tangyouling@xxxxxxxxxxx>
Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
 arch/loongarch/kernel/module.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index c3f9d2f..9e10c44 100644
--- a/arch/loongarch/kernel/module.c
+++ b/arch/loongarch/kernel/module.c
@@ -367,6 +367,15 @@ static int apply_r_larch_got_pc(struct module *mod,
 	return apply_r_larch_pcala(mod, location, got, rela_stack, rela_stack_top, type);
 }
 
+static int apply_r_larch_32_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;
+
+	*(u32 *)location = offset;
+	return 0;
+}
+
 /*
  * reloc_handlers_rela() - Apply a particular relocation to a module
  * @mod: the module to apply the reloc to
@@ -396,6 +405,7 @@ static reloc_rela_handler reloc_rela_handlers[] = {
 	[R_LARCH_SOP_POP_32_S_10_5 ... R_LARCH_SOP_POP_32_U] = apply_r_larch_sop_imm_field,
 	[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,
 };
 
 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
-- 
2.1.0