1/*
2 * Split from entry_32.S
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9
10#include <linux/magic.h>
11#include <asm/reg.h>
12#include <asm/ppc_asm.h>
13#include <asm/asm-offsets.h>
14#include <asm/ftrace.h>
15#include <asm/export.h>
16
17_GLOBAL(mcount)
18_GLOBAL(_mcount)
19	/*
20	 * It is required that _mcount on PPC32 must preserve the
21	 * link register. But we have r0 to play with. We use r0
22	 * to push the return address back to the caller of mcount
23	 * into the ctr register, restore the link register and
24	 * then jump back using the ctr register.
25	 */
26	mflr	r0
27	mtctr	r0
28	lwz	r0, 4(r1)
29	mtlr	r0
30	bctr
31
32_GLOBAL(ftrace_caller)
33	MCOUNT_SAVE_FRAME
34	/* r3 ends up with link register */
35	subi	r3, r3, MCOUNT_INSN_SIZE
36.globl ftrace_call
37ftrace_call:
38	bl	ftrace_stub
39	nop
40#ifdef CONFIG_FUNCTION_GRAPH_TRACER
41.globl ftrace_graph_call
42ftrace_graph_call:
43	b	ftrace_graph_stub
44_GLOBAL(ftrace_graph_stub)
45#endif
46	MCOUNT_RESTORE_FRAME
47	/* old link register ends up in ctr reg */
48	bctr
49
50EXPORT_SYMBOL(_mcount)
51
52_GLOBAL(ftrace_stub)
53	blr
54
55#ifdef CONFIG_FUNCTION_GRAPH_TRACER
56_GLOBAL(ftrace_graph_caller)
57	/* load r4 with local address */
58	lwz	r4, 44(r1)
59	subi	r4, r4, MCOUNT_INSN_SIZE
60
61	/* Grab the LR out of the caller stack frame */
62	lwz	r3,52(r1)
63
64	bl	prepare_ftrace_return
65	nop
66
67        /*
68         * prepare_ftrace_return gives us the address we divert to.
69         * Change the LR in the callers stack frame to this.
70         */
71	stw	r3,52(r1)
72
73	MCOUNT_RESTORE_FRAME
74	/* old link register ends up in ctr reg */
75	bctr
76
77_GLOBAL(return_to_handler)
78	/* need to save return values */
79	stwu	r1, -32(r1)
80	stw	r3, 20(r1)
81	stw	r4, 16(r1)
82	stw	r31, 12(r1)
83	mr	r31, r1
84
85	bl	ftrace_return_to_handler
86	nop
87
88	/* return value has real return address */
89	mtlr	r3
90
91	lwz	r3, 20(r1)
92	lwz	r4, 16(r1)
93	lwz	r31,12(r1)
94	lwz	r1, 0(r1)
95
96	/* Jump back to real return address */
97	blr
98#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
99