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-rw-r--r--arch/mips/kernel/mcount.S55
1 files changed, 34 insertions, 21 deletions
diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S
index 6851fc97a511..6bfcb7a00ec6 100644
--- a/arch/mips/kernel/mcount.S
+++ b/arch/mips/kernel/mcount.S
@@ -6,6 +6,7 @@
* more details.
*
* Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University, China
+ * Copyright (C) 2010 DSLab, Lanzhou University, China
* Author: Wu Zhangjin <wuzhangjin@gmail.com>
*/
@@ -45,8 +46,6 @@
PTR_L a5, PT_R9(sp)
PTR_L a6, PT_R10(sp)
PTR_L a7, PT_R11(sp)
-#endif
-#ifdef CONFIG_64BIT
PTR_ADDIU sp, PT_SIZE
#else
PTR_ADDIU sp, (PT_SIZE + 8)
@@ -58,6 +57,12 @@
move ra, AT
.endm
+/*
+ * The -mmcount-ra-address option of gcc 4.5 uses register $12 to pass
+ * the location of the parent's return address.
+ */
+#define MCOUNT_RA_ADDRESS_REG $12
+
#ifdef CONFIG_DYNAMIC_FTRACE
NESTED(ftrace_caller, PT_SIZE, ra)
@@ -71,14 +76,14 @@ _mcount:
MCOUNT_SAVE_REGS
#ifdef KBUILD_MCOUNT_RA_ADDRESS
- PTR_S t0, PT_R12(sp) /* t0 saved the location of the return address(at) by -mmcount-ra-address */
+ PTR_S MCOUNT_RA_ADDRESS_REG, PT_R12(sp)
#endif
- move a0, ra /* arg1: next ip, selfaddr */
+ move a0, ra /* arg1: self return address */
.globl ftrace_call
ftrace_call:
nop /* a placeholder for the call to a real tracing function */
- move a1, AT /* arg2: the caller's next ip, parent */
+ move a1, AT /* arg2: parent's return address */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call
@@ -119,9 +124,9 @@ NESTED(_mcount, PT_SIZE, ra)
static_trace:
MCOUNT_SAVE_REGS
- move a0, ra /* arg1: next ip, selfaddr */
+ move a0, ra /* arg1: self return address */
jalr t2 /* (1) call *ftrace_trace_function */
- move a1, AT /* arg2: the caller's next ip, parent */
+ move a1, AT /* arg2: parent's return address */
MCOUNT_RESTORE_REGS
.globl ftrace_stub
@@ -134,28 +139,34 @@ 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 */
-#ifdef KBUILD_MCOUNT_RA_ADDRESS
- PTR_L t0, PT_R12(sp) /* load the original t0 from the stack */
-#endif
-#else
+#ifndef CONFIG_DYNAMIC_FTRACE
MCOUNT_SAVE_REGS
- move a1, ra /* arg2: next ip, selfaddr */
#endif
+ /* arg1: Get the location of the parent's return address */
#ifdef KBUILD_MCOUNT_RA_ADDRESS
- bnez t0, 1f /* non-leaf func: t0 saved the location of the return address */
+#ifdef CONFIG_DYNAMIC_FTRACE
+ PTR_L a0, PT_R12(sp)
+#else
+ move a0, MCOUNT_RA_ADDRESS_REG
+#endif
+ bnez a0, 1f /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */
nop
- PTR_LA t0, PT_R1(sp) /* leaf func: get the location of at(old ra) from our own stack */
-1: move a0, t0 /* arg1: the location of the return address */
+#endif
+ PTR_LA a0, PT_R1(sp) /* leaf func: the location in current stack */
+1:
+
+ /* arg2: Get self return address */
+#ifdef CONFIG_DYNAMIC_FTRACE
+ PTR_L a1, PT_R31(sp)
#else
- PTR_LA a0, PT_R1(sp) /* arg1: &AT -> a0 */
+ move a1, ra
#endif
- jal prepare_ftrace_return
+
+ /* arg3: Get frame pointer of current stack */
#ifdef CONFIG_FRAME_POINTER
- move a2, fp /* arg3: frame pointer */
-#else
+ move a2, fp
+#else /* ! CONFIG_FRAME_POINTER */
#ifdef CONFIG_64BIT
PTR_LA a2, PT_SIZE(sp)
#else
@@ -163,6 +174,8 @@ NESTED(ftrace_graph_caller, PT_SIZE, ra)
#endif
#endif
+ jal prepare_ftrace_return
+ nop
MCOUNT_RESTORE_REGS
RETURN_BACK
END(ftrace_graph_caller)