arch/arm/oprofile/common.c

   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
  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
  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
  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(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
 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
 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
 129 void oprofile_arch_exit(void)
 130 {
 131         oprofile_perf_exit();
 132 }