6.6-stable review patch. If anyone has any objections, please let me know.
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From: WangYuli wangyuli@uniontech.com
[ 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@u... Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 46677daf708bd..cc11c4544cffd 100644 --- 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 2e0266ae6bd72..5d1ce8dacaf58 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 norvc\n" + "kgdb_compiled_break: ebreak\n" + ".option rvc\n"); +} + void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer, char *remcom_out_buffer) {