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riscv: KGDB: Do not inline arch_kgdb_breakpoint()

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[ 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: fe89bd2be8 ("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>
This commit is contained in:
WangYuli
2025-04-11 15:32:21 +08:00
committed by Greg Kroah-Hartman
parent ec95d0dfc6
commit ba433e6c10
2 changed files with 9 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
arch/riscv/include/asm/kgdb.h
View File

@@ -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"

8
arch/riscv/kernel/kgdb.c
View File

@@ -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)
{