linux-kernel - [PATCH v2] riscv: KGDB: Do not inline arch_kgdb

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <330B3BAFC6FDB763+20250402074247.64483-1-wangyuli@uniontech.com>
Date: Wed,  2 Apr 2025 15:42:47 +0800
From: WangYuli <wangyuli@...ontech.com>
To: paul.walmsley@...ive.com,
	palmer@...belt.com,
	aou@...s.berkeley.edu,
	alex@...ti.fr
Cc: wangyuli@...ontech.com,
	chenhuacai@...nel.org,
	linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	vincent.chen@...ive.com,
	palmerdabbelt@...gle.com,
	zhanjun@...ontech.com,
	niecheng1@...ontech.com,
	guanwentao@...ontech.com,
	Huacai Chen <chenhuacai@...ngson.cn>
Subject: [PATCH v2] riscv: KGDB: Do not inline arch_kgdb_breakpoint()

The arch_kgdb_breakpoint() function defines the kgdb_compiled_break
symbol using inline assembly.

There's a potential issue where the compiler might inline
arch_kgdb_breakpoint(), which would then define the kgdb_breakinst
symbol multiple times, leading to fail to link vmlinux.o.

This isn't merely a potential compilation problem. The intent here
is to determine the global symbol address of kgdb_compiled_break,
and if this function is inlined multiple times, it would logically
be a grave error.

Link: https://lore.kernel.org/all/4b4187c1-77e5-44b7-885f-d6826723dd9a@sifive.com/
Fixes: fe89bd2be866 ("riscv: Add KGDB support")
Co-developed-by: Huacai Chen <chenhuacai@...ngson.cn>
Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
Signed-off-by: WangYuli <wangyuli@...ontech.com>
---
Changelog:
 *v1->v2: Add the missing __ASSEMBLY__ check and substitute
".option rvc/norvc" with ".option push/pop".
---
 arch/riscv/include/asm/kgdb.h | 9 +--------
 arch/riscv/kernel/kgdb.c      | 8 ++++++++
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/include/asm/kgdb.h b/arch/riscv/include/asm/kgdb.h
index 46677daf708b..d9f6a8fc387f 100644
--- a/arch/riscv/include/asm/kgdb.h
+++ b/arch/riscv/include/asm/kgdb.h
@@ -19,16 +19,9 @@
 
 #ifndef	__ASSEMBLY__
 
+extern void arch_kgdb_breakpoint(void);
 extern unsigned long kgdb_compiled_break;
 
-static inline void arch_kgdb_breakpoint(void)
-{
-	asm(".global kgdb_compiled_break\n"
-	    ".option norvc\n"
-	    "kgdb_compiled_break: ebreak\n"
-	    ".option rvc\n");
-}
-
 #endif /* !__ASSEMBLY__ */
 
 #define DBG_REG_ZERO "zero"
diff --git a/arch/riscv/kernel/kgdb.c b/arch/riscv/kernel/kgdb.c
index 2e0266ae6bd7..5873d3970360 100644
--- a/arch/riscv/kernel/kgdb.c
+++ b/arch/riscv/kernel/kgdb.c
@@ -254,6 +254,14 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 	regs->epc = pc;
 }
 
+noinline void arch_kgdb_breakpoint(void)
+{
+	asm(".global kgdb_compiled_break\n"
+	    ".option push\n"
+	    "kgdb_compiled_break: ebreak\n"
+	    ".option pop\n");
+}
+
 void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
 				char *remcom_out_buffer)
 {
-- 
2.49.0