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 */
32static 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
46char *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
62static 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 */
80struct frame_tail {
81	struct frame_tail *fp;
82	unsigned long sp;
83	unsigned long lr;
84} __attribute__((packed));
85
86static 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(VERIFY_READ, 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
106static 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
121int __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
129void oprofile_arch_exit(void)
130{
131	oprofile_perf_exit();
132}
133