riscv: KGDB: Do not inline arch_kgdb_breakpoint()

[ Upstream commit 3af4bec9c1db3f003be4d5ae09b6a737e4be1612 ]

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_compiled_break
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/
Link: https://lore.kernel.org/all/5b0adf9b-2b22-43fe-ab74-68df94115b9a@ghiti.fr/
Link: https://lore.kernel.org/all/23693e7f-4fff-40f3-a437-e06d827278a5@ghiti.fr/
Fixes: fe89bd2be866 ("riscv: Add KGDB support")
Co-developed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Link: https://lore.kernel.org/r/F22359AFB6FF9FD8+20250411073222.56820-1-wangyuli@uniontech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/riscv/include/asm/kgdb.h b/arch/riscv/include/asm/kgdb.h
index 46677daf708bd0b06a763a8297dfa88f369712d0..cc11c4544cffd133c86a738bcd35c3f75ba59aea 100644 (file)
--- a/arch/riscv/include/asm/kgdb.h
+++ b/arch/riscv/include/asm/kgdb.h
@@ -19,16 +19,9 @@
 
 #ifndef        __ASSEMBLY__
 
+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 2e0266ae6bd728979a7119c6d22695c8f02e6e76..5d1ce8dacaf58fab4329a1a92803f648aede0544 100644 (file)
--- 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 norvc\n"
+           "kgdb_compiled_break: ebreak\n"
+           ".option rvc\n");
+}
+
 void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
                                char *remcom_out_buffer)
 {