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authorSteven Rostedt <rostedt@goodmis.org>2009-02-11 19:10:57 -0500
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-02-23 10:48:55 +1100
commitfad4f47cc8b2b8f7e7d062c40c66188cdf783137 (patch)
treee0c978d7b4ffdf1ae8d7d0795c774c6fad87fdf7 /arch/powerpc/kernel/entry_32.S
parentbf528a3a9bd11b6ae39684b18c9c0678f23924fd (diff)
powerpc32, ftrace: port function graph tracer to ppc32, static only
This patch ports the function graph tracer for PowerPC, but only for static function tracing. Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/entry_32.S')
-rw-r--r--arch/powerpc/kernel/entry_32.S43
1 files changed, 42 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index fd54cb59728..12247b937d2 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -1199,9 +1199,11 @@ _GLOBAL(_mcount)
mtctr r5
bctrl
-
nop
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ b ftrace_graph_caller
+#endif
MCOUNT_RESTORE_FRAME
bctr
@@ -1210,4 +1212,43 @@ _GLOBAL(_mcount)
_GLOBAL(ftrace_stub)
blr
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+_GLOBAL(ftrace_graph_caller)
+ /* load r4 with local address */
+ lwz r4, 44(r1)
+ subi r4, r4, MCOUNT_INSN_SIZE
+
+ /* get the parent address */
+ addi r3, r1, 52
+
+ bl prepare_ftrace_return
+ nop
+
+ MCOUNT_RESTORE_FRAME
+ /* old link register ends up in ctr reg */
+ bctr
+
+_GLOBAL(return_to_handler)
+ /* need to save return values */
+ stwu r1, -32(r1)
+ stw r3, 20(r1)
+ stw r4, 16(r1)
+ stw r31, 12(r1)
+ mr r31, r1
+
+ bl ftrace_return_to_handler
+ nop
+
+ /* return value has real return address */
+ mtlr r3
+
+ lwz r3, 20(r1)
+ lwz r4, 16(r1)
+ lwz r31,12(r1)
+ lwz r1, 0(r1)
+
+ /* Jump back to real return address */
+ blr
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
#endif /* CONFIG_MCOUNT */