[PATCH v4 2/4] LoongArch: Support R_LARCH_SOP_PUSH_GPREL relocation type in kernel module

From: Xi Ruoyao
Date: Fri Jul 29 2022 - 04:40:54 EST


This relocation type pushes the offset of the GOT entry for a symbol
from the beginning of GOT into the relocation stack. Our linker script
has initialized an empty GOT, so we need to create a new GOT entry if
there is no exist one for a symbol.

Signed-off-by: Xi Ruoyao <xry111@xxxxxxxxxxx>
---
arch/loongarch/kernel/module.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index 638427ff0d51..3ac4fbb5f109 100644
--- a/arch/loongarch/kernel/module.c
+++ b/arch/loongarch/kernel/module.c
@@ -122,6 +122,16 @@ static int apply_r_larch_sop_push_plt_pcrel(struct module *mod, u32 *location, E
return apply_r_larch_sop_push_pcrel(mod, location, v, rela_stack, rela_stack_top, type);
}

+static int apply_r_larch_sop_push_gprel(struct module *mod, u32 *location,
+ Elf_Addr v, s64 *rela_stack, size_t *rela_stack_top,
+ unsigned int type)
+{
+ Elf_Addr got = module_emit_got_entry(mod, v);
+ ptrdiff_t offset = (void *)got - (void *)mod->arch.got.shdr->sh_addr;
+
+ return rela_stack_push(offset, rela_stack, rela_stack_top);
+}
+
static int apply_r_larch_sop(struct module *mod, u32 *location, Elf_Addr v,
s64 *rela_stack, size_t *rela_stack_top, unsigned int type)
{
@@ -306,6 +316,7 @@ static reloc_rela_handler reloc_rela_handlers[] = {
[R_LARCH_SOP_PUSH_PCREL] = apply_r_larch_sop_push_pcrel,
[R_LARCH_SOP_PUSH_ABSOLUTE] = apply_r_larch_sop_push_absolute,
[R_LARCH_SOP_PUSH_DUP] = apply_r_larch_sop_push_dup,
+ [R_LARCH_SOP_PUSH_GPREL] = apply_r_larch_sop_push_gprel,
[R_LARCH_SOP_PUSH_PLT_PCREL] = apply_r_larch_sop_push_plt_pcrel,
[R_LARCH_SOP_SUB ... R_LARCH_SOP_IF_ELSE] = apply_r_larch_sop,
[R_LARCH_SOP_POP_32_S_10_5 ... R_LARCH_SOP_POP_32_U] = apply_r_larch_sop_imm_field,
--
2.37.0