ARM: ftrace: function graph tracer support

Cc: Tim Bird <tim.bird@am.sony.com>
[rabin@rab.in: rebase on top of latest code,
	       keep code in ftrace.c instead of separate file,
	       check for ftrace_graph_entry also]
Signed-off-by: Rabin Vincent <rabin@rab.in>

1 files changed, 46 insertions, 0 deletions

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index fe1d5862b19f..9f1766211668 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -148,6 +148,20 @@ ENDPROC(ret_from_fork)
         adr     r0, .Lftrace_stub
         cmp     r0, r2
         bne     1f
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        ldr     r1, =ftrace_graph_return
+        ldr     r2, [r1]
+        cmp     r0, r2
+        bne     ftrace_graph_caller\suffix
+
+        ldr     r1, =ftrace_graph_entry
+        ldr     r2, [r1]
+        ldr     r0, =ftrace_graph_entry_stub
+        cmp     r0, r2
+        bne     ftrace_graph_caller\suffix
+#endif
+
         mcount_exit
 
 1:      mcount_get_lr   r1                      @ lr of instrumented func
@@ -172,6 +186,15 @@ ftrace_call\suffix:
         mcount_exit
 .endm
 
+.macro __ftrace_graph_caller
+        sub     r0, fp, #4              @ &lr of instrumented routine (&parent)
+        mov     r1, lr                  @ instrumented routine (func)
+        sub     r1, r1, #MCOUNT_INSN_SIZE
+        mov     r2, fp                  @ frame pointer
+        bl      prepare_ftrace_return
+        mcount_exit
+.endm
+
 #ifdef CONFIG_OLD_MCOUNT
 /*
  * mcount
@@ -206,6 +229,12 @@ ENTRY(ftrace_caller_old)
 ENDPROC(ftrace_caller_old)
 #endif
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ENTRY(ftrace_graph_caller_old)
+        __ftrace_graph_caller
+ENDPROC(ftrace_graph_caller_old)
+#endif
+
 .purgem mcount_enter
 .purgem mcount_get_lr
 .purgem mcount_exit
@@ -244,10 +273,27 @@ ENTRY(ftrace_caller)
 ENDPROC(ftrace_caller)
 #endif
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ENTRY(ftrace_graph_caller)
+        __ftrace_graph_caller
+ENDPROC(ftrace_graph_caller)
+#endif
+
 .purgem mcount_enter
 .purgem mcount_get_lr
 .purgem mcount_exit
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        .globl return_to_handler
+return_to_handler:
+        stmdb   sp!, {r0-r3}
+        mov     r0, fp                  @ frame pointer
+        bl      ftrace_return_to_handler
+        mov     lr, r0                  @ r0 has real ret addr
+        ldmia   sp!, {r0-r3}
+        mov     pc, lr
+#endif
+
 ENTRY(ftrace_stub)
 .Lftrace_stub:
         mov     pc, lr