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From:   WANG Rui <wangrui@loongson.cn>
To:     Huacai Chen <chenhuacai@kernel.org>
Cc:     WANG Xuerui <kernel@xen0n.name>,
        Jinyang He <hejinyang@loongson.cn>,
        Xi Ruoyao <xry111@xry111.site>, linux-kernel@vger.kernel.org,
        loongarch@lists.linux.dev, linux-kbuild@vger.kernel.org,
        llvm@lists.linux.dev, loongson-kernel@lists.loongnix.cn,
        WANG Rui <wangrui@loongson.cn>
Subject: [PATCH] LoongArch: Record pc instead of offset in la-abs relocation
Date:   Thu, 16 Nov 2023 21:03:31 +0800
Message-ID: <20231116130331.241395-1-wangrui@loongson.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

To clarify, the previous version functioned flawlessly. However, it's
worth noting that the LLVM's LoongArch backend currently lacks support
for cross-section label calculations. With this patch, we enable the use
of clang to compile relocatable kernels.

Signed-off-by: WANG Rui <wangrui@loongson.cn>
---
 arch/loongarch/include/asm/asmmacro.h | 3 +--
 arch/loongarch/include/asm/setup.h    | 2 +-
 arch/loongarch/kernel/relocate.c      | 2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/include/asm/asmmacro.h b/arch/loongarch/include/asm/asmmacro.h
index c9544f358c33..655db7d7a427 100644
--- a/arch/loongarch/include/asm/asmmacro.h
+++ b/arch/loongarch/include/asm/asmmacro.h
@@ -609,8 +609,7 @@
 	lu32i.d	\reg, 0
 	lu52i.d	\reg, \reg, 0
 	.pushsection ".la_abs", "aw", %progbits
-	768:
-	.dword	768b-766b
+	.dword	766b
 	.dword	\sym
 	.popsection
 #endif
diff --git a/arch/loongarch/include/asm/setup.h b/arch/loongarch/include/asm/setup.h
index a0bc159ce8bd..ee52fb1e9963 100644
--- a/arch/loongarch/include/asm/setup.h
+++ b/arch/loongarch/include/asm/setup.h
@@ -25,7 +25,7 @@ extern void set_merr_handler(unsigned long offset, void *addr, unsigned long len
 #ifdef CONFIG_RELOCATABLE
 
 struct rela_la_abs {
-	long offset;
+	long pc;
 	long symvalue;
 };
 
diff --git a/arch/loongarch/kernel/relocate.c b/arch/loongarch/kernel/relocate.c
index 6c3eff9af9fb..288b739ca88d 100644
--- a/arch/loongarch/kernel/relocate.c
+++ b/arch/loongarch/kernel/relocate.c
@@ -52,7 +52,7 @@ static inline void __init relocate_absolute(long random_offset)
 	for (p = begin; (void *)p < end; p++) {
 		long v = p->symvalue;
 		uint32_t lu12iw, ori, lu32id, lu52id;
-		union loongarch_instruction *insn = (void *)p - p->offset;
+		union loongarch_instruction *insn = (void *)p->pc;
 
 		lu12iw = (v >> 12) & 0xfffff;
 		ori    = v & 0xfff;
-- 
2.42.1