linux/arch/s390/include/asm/ftrace.h
Heiko Carstens 7eed2e09ab s390/ftrace: provide working ftrace_return_address()
The common code ftrace_return_address(n), which is just a wrapper for
__builtin_return_address(n), will only work for n > 0 if CONFIG_FRAME_POINTER
is set to 'y'. Otherwise it will return 0.
Since on s390 we will never have that config option set to 'y'
ftrace_return_address() won't work at all for n > 0.

Luckily we always compile the kernel with -mkernel-backchain which
in turn means that __builtin_return_address(n) will always work.

So let ftrace_return_address(n) map to __builtin_return_address(n).

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-11-28 09:47:15 +01:00

70 lines
1.4 KiB
C

#ifndef _ASM_S390_FTRACE_H
#define _ASM_S390_FTRACE_H
#define ARCH_SUPPORTS_FTRACE_OPS 1
#define MCOUNT_INSN_SIZE 24
#define MCOUNT_RETURN_FIXUP 18
#ifndef __ASSEMBLY__
#define ftrace_return_address(n) __builtin_return_address(n)
void _mcount(void);
void ftrace_caller(void);
extern char ftrace_graph_caller_end;
extern unsigned long ftrace_plt;
struct dyn_arch_ftrace { };
#define MCOUNT_ADDR ((unsigned long)_mcount)
#define FTRACE_ADDR ((unsigned long)ftrace_caller)
#define KPROBE_ON_FTRACE_NOP 0
#define KPROBE_ON_FTRACE_CALL 1
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
return addr;
}
struct ftrace_insn {
u16 opc;
s32 disp;
} __packed;
static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
{
#ifdef CONFIG_FUNCTION_TRACER
/* jg .+24 */
insn->opc = 0xc0f4;
insn->disp = MCOUNT_INSN_SIZE / 2;
#endif
}
static inline int is_ftrace_nop(struct ftrace_insn *insn)
{
#ifdef CONFIG_FUNCTION_TRACER
if (insn->disp == MCOUNT_INSN_SIZE / 2)
return 1;
#endif
return 0;
}
static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
unsigned long ip)
{
#ifdef CONFIG_FUNCTION_TRACER
unsigned long target;
/* brasl r0,ftrace_caller */
target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
insn->opc = 0xc005;
insn->disp = (target - ip) / 2;
#endif
}
#endif /* __ASSEMBLY__ */
#endif /* _ASM_S390_FTRACE_H */