From e17ff5fec65a0213416efbe7ceae5f2f9887dda2 Mon Sep 17 00:00:00 2001 From: Wu Zhangjin Date: Fri, 20 Nov 2009 20:34:35 +0800 Subject: [PATCH] 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 Cc: Steven Rostedt Cc: Nicholas Mc Guire Cc: zhangfx@lemote.com Cc: Wu Zhangjin Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Frederic Weisbecker 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 --- arch/mips/kernel/ftrace.c | 21 +++++++++++++++++++++ arch/mips/kernel/mcount.S | 14 ++++++++++++-- 2 files changed, 33 insertions(+), 2 deletions(-) diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index 65a3f8a..e981a49 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -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 */ diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index b50e38d8..98d4690 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -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 */ -- 1.8.2.3