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 char *op_name_from_perf_id(void)
  27 {
  28         enum arm_perf_pmu_ids id = armpmu_get_pmu_id();
  29
  30         switch (id) {
  31         case ARM_PERF_PMU_ID_XSCALE1:
  32                 return "arm/xscale1";
  33         case ARM_PERF_PMU_ID_XSCALE2:
  34                 return "arm/xscale2";
  35         case ARM_PERF_PMU_ID_V6:
  36                 return "arm/armv6";
  37         case ARM_PERF_PMU_ID_V6MP:
  38                 return "arm/mpcore";
  39         case ARM_PERF_PMU_ID_CA8:
  40                 return "arm/armv7";
  41         case ARM_PERF_PMU_ID_CA9:
  42                 return "arm/armv7-ca9";
  43         default:
  44                 return NULL;
  45         }
  46 }
  47 #endif
  48
  49 static int report_trace(struct stackframe *frame, void *d)
  50 {
  51         unsigned int *depth = d;
  52
  53         if (*depth) {
  54                 oprofile_add_trace(frame->pc);
  55                 (*depth)--;
  56         }
  57
  58         return *depth == 0;
  59 }
  60
  61 /*
  62  * The registers we're interested in are at the end of the variable
  63  * length saved register structure. The fp points at the end of this
  64  * structure so the address of this struct is:
  65  * (struct frame_tail *)(xxx->fp)-1
  66  */
  67 struct frame_tail {
  68         struct frame_tail *fp;
  69         unsigned long sp;
  70         unsigned long lr;
  71 } __attribute__((packed));
  72
  73 static struct frame_tail* user_backtrace(struct frame_tail *tail)
  74 {
  75         struct frame_tail buftail[2];
  76
  77         /* Also check accessibility of one struct frame_tail beyond */
  78         if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
  79                 return NULL;
  80         if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
  81                 return NULL;
  82
  83         oprofile_add_trace(buftail[0].lr);
  84
  85         /* frame pointers should strictly progress back up the stack
  86          * (towards higher addresses) */
  87         if (tail + 1 >= buftail[0].fp)
  88                 return NULL;
  89
  90         return buftail[0].fp-1;
  91 }
  92
  93 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
  94 {
  95         struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
  96
  97         if (!user_mode(regs)) {
  98                 struct stackframe frame;
  99                 frame.fp = regs->ARM_fp;
 100                 frame.sp = regs->ARM_sp;
 101                 frame.lr = regs->ARM_lr;
 102                 frame.pc = regs->ARM_pc;
 103                 walk_stackframe(&frame, report_trace, &depth);
 104                 return;
 105         }
 106
 107         while (depth-- && tail && !((unsigned long) tail & 3))
 108                 tail = user_backtrace(tail);
 109 }
 110
 111 int __init oprofile_arch_init(struct oprofile_operations *ops)
 112 {
 113         /* provide backtrace support also in timer mode: */
 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 }