From f768a20c0a6e5f2396b9ab99bbbfd39d91228df9 Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Fri, 24 Sep 2021 15:03:07 +0200 Subject: [PATCH] s390/ftrace: add FTRACE_GEN_NOP_ASM macro FTRACE_GEN_NOP_ASM(name) can be used to generate assembly functions with the required information added to allow tracing via kprobes/ftrace. It adds the nop instruction which will be patched by ftrace later. If the compiler supports -mnop-mcount it will also add an entry to the __mcount_loc section. Signed-off-by: Sven Schnelle Acked-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- arch/s390/include/asm/ftrace.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index e8b460f39c58..d1841f4176be 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -68,4 +68,32 @@ static inline bool arch_syscall_match_sym_name(const char *sym, } #endif /* __ASSEMBLY__ */ + +#ifdef CONFIG_FUNCTION_TRACER + +#define FTRACE_NOP_INSN .word 0xc004, 0x0000, 0x0000 /* brcl 0,0 */ + +#ifndef CC_USING_HOTPATCH + +#define FTRACE_GEN_MCOUNT_RECORD(name) \ + .section __mcount_loc, "a", @progbits; \ + .quad name; \ + .previous; + +#else /* !CC_USING_HOTPATCH */ + +#define FTRACE_GEN_MCOUNT_RECORD(name) + +#endif /* !CC_USING_HOTPATCH */ + +#define FTRACE_GEN_NOP_ASM(name) \ + FTRACE_GEN_MCOUNT_RECORD(name) \ + FTRACE_NOP_INSN + +#else /* CONFIG_FUNCTION_TRACER */ + +#define FTRACE_GEN_NOP_ASM(name) + +#endif /* CONFIG_FUNCTION_TRACER */ + #endif /* _ASM_S390_FTRACE_H */