Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37;
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
To:     Huacai Chen <chenhuacai@kernel.org>
Cc:     loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
        loongson-kernel@lists.loongnix.cn
Subject: [PATCH v1 3/3] LoongArch: Add support for 64_PCREL relocation type
Date:   Tue, 26 Sep 2023 16:10:52 +0800
Message-Id: <1695715852-15902-4-git-send-email-yangtiezhu@loongson.cn>
In-Reply-To: <1695715852-15902-1-git-send-email-yangtiezhu@loongson.cn>
References: <1695715852-15902-1-git-send-email-yangtiezhu@loongson.cn>
Precedence: bulk

When build and update kernel with the latest upstream binutils and
loongson3_defconfig, the serial console works well with the previous
32_PCREL patch, but it can not enter the graphical interface due to
it failed to start lightdm service, there are more info like this:

  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
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: <stable@vger.kernel.org>
---
 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 9e10c44..b13b285 100644
--- a/arch/loongarch/kernel/module.c
+++ b/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,
-- 
2.1.0