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/err.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16 #include <linux/mutex.h>
  17 #include <linux/oprofile.h>
  18 #include <linux/perf_event.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/slab.h>
  21 #include <asm/stacktrace.h>
  22 #include <linux/uaccess.h>
  23
  24 #include <asm/perf_event.h>
  25 #include <asm/ptrace.h>
  26
  27 #ifdef CONFIG_HW_PERF_EVENTS
  28 char *op_name_from_perf_id(void)
  29 {
  30         enum arm_perf_pmu_ids id = armpmu_get_pmu_id();
  31
  32         switch (id) {
  33         case ARM_PERF_PMU_ID_XSCALE1:
  34                 return "arm/xscale1";
  35         case ARM_PERF_PMU_ID_XSCALE2:
  36                 return "arm/xscale2";
  37         case ARM_PERF_PMU_ID_V6:
  38                 return "arm/armv6";
  39         case ARM_PERF_PMU_ID_V6MP:
  40                 return "arm/mpcore";
  41         case ARM_PERF_PMU_ID_CA8:
  42                 return "arm/armv7";
  43         case ARM_PERF_PMU_ID_CA9:
  44                 return "arm/armv7-ca9";
  45         default:
  46                 return NULL;
  47         }
  48 }
  49
  50 static int report_trace(struct stackframe *frame, void *d)
  51 {
  52         unsigned int *depth = d;
  53
  54         if (*depth) {
  55                 oprofile_add_trace(frame->pc);
  56                 (*depth)--;
  57         }
  58
  59         return *depth == 0;
  60 }
  61
  62 /*
  63  * The registers we're interested in are at the end of the variable
  64  * length saved register structure. The fp points at the end of this
  65  * structure so the address of this struct is:
  66  * (struct frame_tail *)(xxx->fp)-1
  67  */
  68 struct frame_tail {
  69         struct frame_tail *fp;
  70         unsigned long sp;
  71         unsigned long lr;
  72 } __attribute__((packed));
  73
  74 static struct frame_tail* user_backtrace(struct frame_tail *tail)
  75 {
  76         struct frame_tail buftail[2];
  77
  78         /* Also check accessibility of one struct frame_tail beyond */
  79         if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
  80                 return NULL;
  81         if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
  82                 return NULL;
  83
  84         oprofile_add_trace(buftail[0].lr);
  85
  86         /* frame pointers should strictly progress back up the stack
  87          * (towards higher addresses) */
  88         if (tail >= buftail[0].fp)
  89                 return NULL;
  90
  91         return buftail[0].fp-1;
  92 }
  93
  94 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
  95 {
  96         struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
  97
  98         if (!user_mode(regs)) {
  99                 struct stackframe frame;
 100                 frame.fp = regs->ARM_fp;
 101                 frame.sp = regs->ARM_sp;
 102                 frame.lr = regs->ARM_lr;
 103                 frame.pc = regs->ARM_pc;
 104                 walk_stackframe(&frame, report_trace, &depth);
 105                 return;
 106         }
 107
 108         while (depth-- && tail && !((unsigned long) tail & 3))
 109                 tail = user_backtrace(tail);
 110 }
 111
 112 int __init oprofile_arch_init(struct oprofile_operations *ops)
 113 {
 114         ops->backtrace          = arm_backtrace;
 115
 116         return oprofile_perf_init(ops);
 117 }
 118
 119 void __exit oprofile_arch_exit(void)
 120 {
 121         oprofile_perf_exit();
 122 }
 123 #else
 124 int __init oprofile_arch_init(struct oprofile_operations *ops)
 125 {
 126         pr_info("oprofile: hardware counters not available\n");
 127         return -ENODEV;
 128 }
 129 void __exit oprofile_arch_exit(void) {}
 130 #endif /* CONFIG_HW_PERF_EVENTS */