Linux Kernel  3.7.1
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common.c
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1 
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  { "xscale1", "arm/xscale1" },
37  { "xscale1", "arm/xscale2" },
38  { "v6", "arm/armv6" },
39  { "v6mpcore", "arm/mpcore" },
40  { "ARMv7 Cortex-A8", "arm/armv7" },
41  { "ARMv7 Cortex-A9", "arm/armv7-ca9" },
42 };
43 
44 char *op_name_from_perf_id(void)
45 {
46  int i;
47  struct op_perf_name names;
48  const char *perf_name = perf_pmu_name();
49 
50  for (i = 0; i < ARRAY_SIZE(op_perf_name_map); ++i) {
51  names = op_perf_name_map[i];
52  if (!strcmp(names.perf_name, perf_name))
53  return names.op_name;
54  }
55 
56  return NULL;
57 }
58 #endif
59 
60 static int report_trace(struct stackframe *frame, void *d)
61 {
62  unsigned int *depth = d;
63 
64  if (*depth) {
65  oprofile_add_trace(frame->pc);
66  (*depth)--;
67  }
68 
69  return *depth == 0;
70 }
71 
72 /*
73  * The registers we're interested in are at the end of the variable
74  * length saved register structure. The fp points at the end of this
75  * structure so the address of this struct is:
76  * (struct frame_tail *)(xxx->fp)-1
77  */
78 struct frame_tail {
79  struct frame_tail *fp;
80  unsigned long sp;
81  unsigned long lr;
82 } __attribute__((packed));
83 
84 static struct frame_tail* user_backtrace(struct frame_tail *tail)
85 {
86  struct frame_tail buftail[2];
87 
88  /* Also check accessibility of one struct frame_tail beyond */
89  if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
90  return NULL;
91  if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
92  return NULL;
93 
94  oprofile_add_trace(buftail[0].lr);
95 
96  /* frame pointers should strictly progress back up the stack
97  * (towards higher addresses) */
98  if (tail + 1 >= buftail[0].fp)
99  return NULL;
100 
101  return buftail[0].fp-1;
102 }
103 
104 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
105 {
106  struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
107 
108  if (!user_mode(regs)) {
109  struct stackframe frame;
110  frame.fp = regs->ARM_fp;
111  frame.sp = regs->ARM_sp;
112  frame.lr = regs->ARM_lr;
113  frame.pc = regs->ARM_pc;
114  walk_stackframe(&frame, report_trace, &depth);
115  return;
116  }
117 
118  while (depth-- && tail && !((unsigned long) tail & 3))
119  tail = user_backtrace(tail);
120 }
121 
123 {
124  /* provide backtrace support also in timer mode: */
125  ops->backtrace = arm_backtrace;
126 
127  return oprofile_perf_init(ops);
128 }
129 
131 {
133 }