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authorWu Zhangjin <wuzhangjin@gmail.com>2009-11-20 20:34:37 +0800
committerRalf Baechle <ralf@linux-mips.org>2009-12-17 01:57:26 +0000
commitfc49a3be2be7a0cd44fcd3b37557d6d92cae59b1 (patch)
treed216d6b5a23c85ee5bcd3b92dd62a4c6718bd72e /arch/mips/kernel
parent046199cae714a7f9e88f5a7940b077f4515f48cb (diff)
MIPS: Tracing: Reserve $12(t0) for mcount-ra-address of gcc 4.5
A new option -mmcount-ra-address for gcc 4.5 have been sent by David Daney <ddaney@caviumnetworks.com> in the thread "MIPS: Add option to pass return address location to _mcount", which help to record the location of the return address(ra) for the function graph tracer of MIPS to hijack the return address easier and safer. that option used the $12(t0) register by default, so, we reserve it for it, and use t1,t2,t3 instead of t0,t1,t2. 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/680/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel')
-rw-r--r--arch/mips/kernel/mcount.S26
1 files changed, 13 insertions, 13 deletions
diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S
index bdfef2c24f16..522e91c688fc 100644
--- a/arch/mips/kernel/mcount.S
+++ b/arch/mips/kernel/mcount.S
@@ -65,8 +65,8 @@ NESTED(ftrace_caller, PT_SIZE, ra)
_mcount:
b ftrace_stub
nop
- lw t0, function_trace_stop
- bnez t0, ftrace_stub
+ lw t1, function_trace_stop
+ bnez t1, ftrace_stub
nop
MCOUNT_SAVE_REGS
@@ -93,21 +93,21 @@ ftrace_stub:
#else /* ! CONFIG_DYNAMIC_FTRACE */
NESTED(_mcount, PT_SIZE, ra)
- lw t0, function_trace_stop
- bnez t0, ftrace_stub
+ lw t1, function_trace_stop
+ bnez t1, ftrace_stub
nop
- PTR_LA t0, ftrace_stub
- PTR_L t1, ftrace_trace_function /* Prepare t1 for (1) */
- bne t0, t1, static_trace
+ PTR_LA t1, ftrace_stub
+ PTR_L t2, ftrace_trace_function /* Prepare t2 for (1) */
+ bne t1, t2, static_trace
nop
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- PTR_L t2, ftrace_graph_return
- bne t0, t2, ftrace_graph_caller
+ PTR_L t3, ftrace_graph_return
+ bne t1, t3, ftrace_graph_caller
nop
- PTR_LA t0, ftrace_graph_entry_stub
- PTR_L t2, ftrace_graph_entry
- bne t0, t2, ftrace_graph_caller
+ PTR_LA t1, ftrace_graph_entry_stub
+ PTR_L t3, ftrace_graph_entry
+ bne t1, t3, ftrace_graph_caller
nop
#endif
b ftrace_stub
@@ -117,7 +117,7 @@ static_trace:
MCOUNT_SAVE_REGS
move a0, ra /* arg1: next ip, selfaddr */
- jalr t1 /* (1) call *ftrace_trace_function */
+ jalr t2 /* (1) call *ftrace_trace_function */
move a1, AT /* arg2: the caller's next ip, parent */
MCOUNT_RESTORE_REGS