linux-kernel - [PATCH] ARM: module: use sign_extend32() to extend the signedness

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Message-Id: <20230530180308.112297-1-masahiroy@kernel.org>
Date:   Wed, 31 May 2023 03:03:08 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     patches@...linux.org.uk
Cc:     linux-kernel@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        Masahiro Yamada <masahiroy@...nel.org>,
        Russell King <linux@...linux.org.uk>
Subject: [PATCH] ARM: module: use sign_extend32() to extend the signedness

The function name clarifies the intention.

Signed-off-by: Masahiro Yamada <masahiroy@...nel.org>
---

KernelVersion: v6.4-rc1

 arch/arm/kernel/module.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index d59c36dc0494..e74d84f58b77 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -169,8 +169,7 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 
 			offset = __mem_to_opcode_arm(*(u32 *)loc);
 			offset = (offset & 0x00ffffff) << 2;
-			if (offset & 0x02000000)
-				offset -= 0x04000000;
+			offset = sign_extend32(offset, 25);
 
 			offset += sym->st_value - loc;
 
@@ -236,7 +235,7 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 		case R_ARM_MOVT_PREL:
 			offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
 			offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
-			offset = (offset ^ 0x8000) - 0x8000;
+			offset = sign_extend32(offset, 15);
 
 			offset += sym->st_value;
 			if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_PREL ||
@@ -344,8 +343,7 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 				((~(j2 ^ sign) & 1) << 22) |
 				((upper & 0x03ff) << 12) |
 				((lower & 0x07ff) << 1);
-			if (offset & 0x01000000)
-				offset -= 0x02000000;
+			offset = sign_extend32(offset, 24);
 			offset += sym->st_value - loc;
 
 			/*
@@ -401,7 +399,7 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 			offset = ((upper & 0x000f) << 12) |
 				((upper & 0x0400) << 1) |
 				((lower & 0x7000) >> 4) | (lower & 0x00ff);
-			offset = (offset ^ 0x8000) - 0x8000;
+			offset = sign_extend32(offset, 15);
 			offset += sym->st_value;
 
 			if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_PREL ||
-- 
2.39.2