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Subject[PATCH 7/8] LoongArch: Support R_LARCH_PCALA* in modules
Date
GCC >= 13 and GNU assembler >= 2.40 use these relocations to address
local symbols, so we need to add them.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
---
arch/loongarch/kernel/module.c | 43 ++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)

diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index 54be05c62145..61ecd174dd03 100644
--- a/arch/loongarch/kernel/module.c
+++ b/arch/loongarch/kernel/module.c
@@ -348,6 +348,48 @@ static int apply_r_larch_abs(struct module *mod, u32 *location, Elf_Addr v,

return 0;
}
+
+static int apply_r_larch_pcala(struct module *mod, u32 *location, Elf_Addr v,
+ s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
+{
+ union loongarch_instruction *insn = (union loongarch_instruction *)location;
+ /* Use s32 for a sign-extension deliberately. */
+ s32 offset_hi20 = (void *)((v + 0x800) & ~0xfff) -
+ (void *)((Elf_Addr)location & ~0xfff);
+ Elf_Addr anchor = (((Elf_Addr)location) & ~0xfff) + offset_hi20;
+ ptrdiff_t offset_rem = (void *)v - (void *)anchor;
+
+ switch (type) {
+ case R_LARCH_PCALA_HI20:
+ v = offset_hi20 >> 12;
+ break;
+ case R_LARCH_PCALA64_LO20:
+ v = offset_rem >> 32;
+ break;
+ case R_LARCH_PCALA64_HI12:
+ v = offset_rem >> 52;
+ break;
+ default:
+ /* Do nothing. */
+ }
+
+ switch (type) {
+ case R_LARCH_PCALA_HI20:
+ case R_LARCH_PCALA64_LO20:
+ insn->reg1i20_format.immediate = v & 0xfffff;
+ break;
+ case R_LARCH_PCALA_LO12:
+ case R_LARCH_PCALA64_HI12:
+ insn->reg2i12_format.immediate = v & 0xfff;
+ break;
+ default:
+ pr_err("%s: Unsupport relocation type %u\n", mod->name, type);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
/*
* reloc_handlers_rela() - Apply a particular relocation to a module
* @mod: the module to apply the reloc to
@@ -379,6 +421,7 @@ static reloc_rela_handler reloc_rela_handlers[] = {
[R_LARCH_ADD32 ... R_LARCH_SUB64] = apply_r_larch_add_sub,
[R_LARCH_B26] = apply_r_larch_b26,
[R_LARCH_ABS_HI20...R_LARCH_ABS64_HI12] = apply_r_larch_abs,
+ [R_LARCH_PCALA_HI20...R_LARCH_PCALA64_HI12] = apply_r_larch_pcala,
};

int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
--
2.37.0
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