Unverified Commit 3af4bec9 authored by WangYuli's avatar WangYuli Committed by Palmer Dabbelt
Browse files

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_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: fe89bd2b ("riscv: Add KGDB support")
Co-developed-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Signed-off-by: default avatarWangYuli <wangyuli@uniontech.com>
Link: https://lore.kernel.org/r/F22359AFB6FF9FD8+20250411073222.56820-1-wangyuli@uniontech.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 0af2f6be

arch/riscv/include/asm/kgdb.h

+1 −8
Original line number Diff line number Diff line
@@ -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"

arch/riscv/kernel/kgdb.c

+8 −0
Original line number Diff line number Diff line
@@ -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)

{