1 /**
2 * @file common.c
3 *
4 * @remark Copyright 2004 Oprofile Authors
5 * @remark Copyright 2010 ARM Ltd.
6 * @remark Read the file COPYING
7 *
8 * @author Zwane Mwaikambo
9 * @author Will Deacon [move to perf]
10 */
11
12 #include <linux/cpumask.h>
13 #include <linux/init.h>
14 #include <linux/mutex.h>
15 #include <linux/oprofile.h>
16 #include <linux/perf_event.h>
17 #include <linux/platform_device.h>
18 #include <linux/slab.h>
19 #include <asm/stacktrace.h>
20 #include <linux/uaccess.h>
21
22 #include <asm/perf_event.h>
23 #include <asm/ptrace.h>
24
25 #ifdef CONFIG_HW_PERF_EVENTS
26
27 /*
28 * OProfile has a curious naming scheme for the ARM PMUs, but they are
29 * part of the user ABI so we need to map from the perf PMU name for
30 * supported PMUs.
31 */
32 static struct op_perf_name {
33 char *perf_name;
34 char *op_name;
35 } op_perf_name_map[] = {
36 { "armv5_xscale1", "arm/xscale1" },
37 { "armv5_xscale2", "arm/xscale2" },
38 { "armv6_1136", "arm/armv6" },
39 { "armv6_1156", "arm/armv6" },
40 { "armv6_1176", "arm/armv6" },
41 { "armv6_11mpcore", "arm/mpcore" },
42 { "armv7_cortex_a8", "arm/armv7" },
43 { "armv7_cortex_a9", "arm/armv7-ca9" },
44 };
45
op_name_from_perf_id(void)46 char *op_name_from_perf_id(void)
47 {
48 int i;
49 struct op_perf_name names;
50 const char *perf_name = perf_pmu_name();
51
52 for (i = 0; i < ARRAY_SIZE(op_perf_name_map); ++i) {
53 names = op_perf_name_map[i];
54 if (!strcmp(names.perf_name, perf_name))
55 return names.op_name;
56 }
57
58 return NULL;
59 }
60 #endif
61
report_trace(struct stackframe * frame,void * d)62 static int report_trace(struct stackframe *frame, void *d)
63 {
64 unsigned int *depth = d;
65
66 if (*depth) {
67 oprofile_add_trace(frame->pc);
68 (*depth)--;
69 }
70
71 return *depth == 0;
72 }
73
74 /*
75 * The registers we're interested in are at the end of the variable
76 * length saved register structure. The fp points at the end of this
77 * structure so the address of this struct is:
78 * (struct frame_tail *)(xxx->fp)-1
79 */
80 struct frame_tail {
81 struct frame_tail *fp;
82 unsigned long sp;
83 unsigned long lr;
84 } __attribute__((packed));
85
user_backtrace(struct frame_tail * tail)86 static struct frame_tail* user_backtrace(struct frame_tail *tail)
87 {
88 struct frame_tail buftail[2];
89
90 /* Also check accessibility of one struct frame_tail beyond */
91 if (!access_ok(tail, sizeof(buftail)))
92 return NULL;
93 if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
94 return NULL;
95
96 oprofile_add_trace(buftail[0].lr);
97
98 /* frame pointers should strictly progress back up the stack
99 * (towards higher addresses) */
100 if (tail + 1 >= buftail[0].fp)
101 return NULL;
102
103 return buftail[0].fp-1;
104 }
105
arm_backtrace(struct pt_regs * const regs,unsigned int depth)106 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
107 {
108 struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
109
110 if (!user_mode(regs)) {
111 struct stackframe frame;
112 arm_get_current_stackframe(regs, &frame);
113 walk_stackframe(&frame, report_trace, &depth);
114 return;
115 }
116
117 while (depth-- && tail && !((unsigned long) tail & 3))
118 tail = user_backtrace(tail);
119 }
120
oprofile_arch_init(struct oprofile_operations * ops)121 int __init oprofile_arch_init(struct oprofile_operations *ops)
122 {
123 /* provide backtrace support also in timer mode: */
124 ops->backtrace = arm_backtrace;
125
126 return oprofile_perf_init(ops);
127 }
128
oprofile_arch_exit(void)129 void oprofile_arch_exit(void)
130 {
131 oprofile_perf_exit();
132 }
133
