LXR linux/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 */
  32static 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
  46char *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
  62static 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 */
  80struct frame_tail {
  81        struct frame_tail *fp;
  82        unsigned long sp;
  83        unsigned long lr;
  84} __attribute__((packed));
  85
  86static 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
 106static 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
 121int __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
 129void oprofile_arch_exit(void)
 130{
 131        oprofile_perf_exit();
 132}
 133