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         { "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
 122 int __init oprofile_arch_init(struct oprofile_operations *ops)
 123 {
 124         /* provide backtrace support also in timer mode: */
 125         ops->backtrace          = arm_backtrace;
 126
 127         return oprofile_perf_init(ops);
 128 }
 129
 130 void oprofile_arch_exit(void)
 131 {
 132         oprofile_perf_exit();
 133 }