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authorMichal Simek <monstr@monstr.eu>2009-12-10 14:15:44 +0100
committerMichal Simek <monstr@monstr.eu>2009-12-14 08:44:01 +0100
commit7d241ff0567b9503d79ee775c40927d09b509f83 (patch)
tree8de1af72c5643416ee427edc7e9ff2170e0d73db /arch/microblaze/kernel/mcount.S
parent6d9e60ce30a1be35491c74df00aaa25d869f8a02 (diff)
downloadlinux-linaro-stable-7d241ff0567b9503d79ee775c40927d09b509f83.tar.gz
microblaze: ftrace: Add dynamic trace support
With dynamic function tracer, by default, _mcount is defined as an "empty" function, it returns directly without any more action. When enabling it in user-space, it will jump to a real tracing function(ftrace_caller), and do the real job for us. Differ from the static function tracer, dynamic function tracer provides two functions ftrace_make_call()/ftrace_make_nop() to enable/disable the tracing of some indicated kernel functions(set_ftrace_filter). In the kernel version, there is only one "_mcount" string for every kernel function, so, we just need to match this one in mcount_regex of scripts/recordmcount.pl. For more information please look at code and Documentation/trace folder. Steven ACK that scripts/recordmcount.pl part. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Michal Simek <monstr@monstr.eu>
Diffstat (limited to 'arch/microblaze/kernel/mcount.S')
-rw-r--r--arch/microblaze/kernel/mcount.S13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/microblaze/kernel/mcount.S b/arch/microblaze/kernel/mcount.S
index 97eef3eea944..30aaf8fb55b2 100644
--- a/arch/microblaze/kernel/mcount.S
+++ b/arch/microblaze/kernel/mcount.S
@@ -83,6 +83,12 @@ ENTRY(ftrace_stub)
nop;
ENTRY(_mcount)
+#ifdef CONFIG_DYNAMIC_FTRACE
+ENTRY(ftrace_caller)
+ /* MS: It is just barrier which is removed from C code */
+ rtsd r15, 8
+ nop
+#endif /* CONFIG_DYNAMIC_FTRACE */
SAVE_REGS
swi r15, r1, 0;
/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST begin of checking */
@@ -90,12 +96,19 @@ ENTRY(_mcount)
bneid r5, end;
nop;
/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST end of checking */
+#ifndef CONFIG_DYNAMIC_FTRACE
/* MS: test function trace if is taken or not */
lwi r20, r0, ftrace_trace_function;
addik r6, r0, ftrace_stub;
cmpu r5, r20, r6; /* ftrace_trace_function != ftrace_stub */
beqid r5, end; /* MS: not taken -> jump over */
nop;
+#else /* CONFIG_DYNAMIC_FTRACE */
+NOALIGN_ENTRY(ftrace_call)
+/* instruction for setup imm FUNC_part1, addik r20, r0, FUNC_part2 */
+ nop
+ nop
+#endif /* CONFIG_DYNAMIC_FTRACE */
/* static normal trace */
lwi r6, r1, 120; /* MS: load parent addr */
addik r5, r15, 0; /* MS: load current function addr */