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MIPS: Tracing: Add dynamic function graph tracer for MIPS 

This patch make function graph tracer work with dynamic function tracer.

To share the source code of dynamic function tracer(MCOUNT_SAVE_REGS),
and avoid restoring the whole saved registers, we need to restore the ra
register from the stack.

(NOTE: This not work with 32bit! need to ensure why!)

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: zhangfx@lemote.com
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/678/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Wu Zhangjin 2009-11-20 20:34:35 +08:00 committed by Ralf Baechle
parent 29c5d3462f
commit e17ff5fec6
2 changed files with 33 additions and 2 deletions
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21
arch/mips/kernel/ftrace.c
View File

@ -115,6 +115,27 @@ int __init ftrace_dyn_arch_init(void *data)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
extern void ftrace_graph_call(void);
#define JMP 0x08000000 /* jump to target directly */
#define CALL_FTRACE_GRAPH_CALLER \
jump_insn_encode(JMP, (unsigned long)(&ftrace_graph_caller))
#define FTRACE_GRAPH_CALL_IP ((unsigned long)(&ftrace_graph_call))
int ftrace_enable_ftrace_graph_caller(void)
{
return ftrace_modify_code(FTRACE_GRAPH_CALL_IP,
CALL_FTRACE_GRAPH_CALLER);
}
int ftrace_disable_ftrace_graph_caller(void)
{
return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, ftrace_nop);
}
#endif /* !CONFIG_DYNAMIC_FTRACE */
#define S_RA_SP (0xafbf << 16) /* s{d,w} ra, offset(sp) */
#define S_R_SP (0xafb0 << 16) /* s{d,w} R, offset(sp) */
#define OFFSET_MASK 0xffff /* stack offset range: 0 ~ PT_SIZE */

14
arch/mips/kernel/mcount.S
View File

@ -77,6 +77,13 @@ ftrace_call:
nop /* a placeholder for the call to a real tracing function */
move a1, AT /* arg2: the caller's next ip, parent */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call
ftrace_graph_call:
nop
nop
#endif
MCOUNT_RESTORE_REGS
.globl ftrace_stub
ftrace_stub:
@ -124,10 +131,13 @@ ftrace_stub:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
NESTED(ftrace_graph_caller, PT_SIZE, ra)
#ifdef CONFIG_DYNAMIC_FTRACE
PTR_L a1, PT_R31(sp) /* load the original ra from the stack */
#else
MCOUNT_SAVE_REGS
PTR_LA a0, PT_R1(sp) /* arg1: &AT -> a0 */
move a1, ra /* arg2: next ip, selfaddr */
#endif
PTR_LA a0, PT_R1(sp) /* arg1: &AT -> a0 */
jal prepare_ftrace_return
move a2, fp /* arg3: frame pointer */