[PATCH v2] RISC-V: Support 32_PCREL relocation type in kernel module

Nylon Chen
2023-06-15T07:23:17Z

Fix the 'unsupported relocation type' error caused by
enabling the -fasynchronous-unwind-tables flag,
which generates relocation types that are not supported.

Signed-off-by: Nylon Chen <nylon.chen@sifive.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
---
Changed in v2:
- add commit message.

arch/riscv/kernel/module.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index 7c651d55fcbd..65be0360a494 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -310,6 +310,15 @@ static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
return 0;
}

+static int apply_r_riscv_pcrel_32_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - (void *)location;
+
+ *location = (*location & 0xffff0000) | (offset & 0xffff);
+ return 0;
+}
+
static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
Elf_Addr v) = {
[R_RISCV_32] = apply_r_riscv_32_rela,
@@ -335,6 +344,7 @@ static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
[R_RISCV_SUB16] = apply_r_riscv_sub16_rela,
[R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
[R_RISCV_SUB64] = apply_r_riscv_sub64_rela,
+ [R_RISCV_32_PCREL] = apply_r_riscv_pcrel_32_rela,
};

int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
--
2.40.1