1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Split from entry_32.S
*/
#include <linux/magic.h>
#include <asm/reg.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ftrace.h>
#include <asm/export.h>
_GLOBAL(mcount)
_GLOBAL(_mcount)
/*
* It is required that _mcount on PPC32 must preserve the
* link register. But we have r0 to play with. We use r0
* to push the return address back to the caller of mcount
* into the ctr register, restore the link register and
* then jump back using the ctr register.
*/
mflr r0
mtctr r0
lwz r0, 4(r1)
mtlr r0
bctr
_GLOBAL(ftrace_caller)
MCOUNT_SAVE_FRAME
/* r3 ends up with link register */
subi r3, r3, MCOUNT_INSN_SIZE
.globl ftrace_call
ftrace_call:
bl ftrace_stub
nop
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call
ftrace_graph_call:
b ftrace_graph_stub
_GLOBAL(ftrace_graph_stub)
#endif
MCOUNT_RESTORE_FRAME
/* old link register ends up in ctr reg */
bctr
EXPORT_SYMBOL(_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
/* Grab the LR out of the caller stack frame */
lwz r3,52(r1)
bl prepare_ftrace_return
nop
/*
* prepare_ftrace_return gives us the address we divert to.
* Change the LR in the callers stack frame to this.
*/
stw r3,52(r1)
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 */
|
