perfmon.c

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#include <linux/kernel.h>
#include <linux/oprofile.h>
#include <linux/sched.h>
#include <asm/perfmon.h>
#include <asm/ptrace.h>
#include <asm/errno.h>

static int allow_ints;

static int
perfmon_handler(struct task_struct *task, void *buf, pfm_ovfl_arg_t *arg,
                struct pt_regs *regs, unsigned long stamp)
{
    int event = arg->pmd_eventid;
 
    arg->ovfl_ctrl.bits.reset_ovfl_pmds = 1;

    /* the owner of the oprofile event buffer may have exited
     * without perfmon being shutdown (e.g. SIGSEGV)
     */
    if (allow_ints)
        oprofile_add_sample(regs, event);
    return 0;
}


static int perfmon_start(void)
{
    allow_ints = 1;
    return 0;
}


static void perfmon_stop(void)
{
    allow_ints = 0;
}


#define OPROFILE_FMT_UUID { \
    0x77, 0x7a, 0x6e, 0x61, 0x20, 0x65, 0x73, 0x69, 0x74, 0x6e, 0x72, 0x20, 0x61, 0x65, 0x0a, 0x6c }

static pfm_buffer_fmt_t oprofile_fmt = {
    .fmt_name       = "oprofile_format",
    .fmt_uuid       = OPROFILE_FMT_UUID,
    .fmt_handler        = perfmon_handler,
};


static char *get_cpu_type(void)
{
    __u8 family = local_cpu_data->family;

    switch (family) {
        case 0x07:
            return "ia64/itanium";
        case 0x1f:
            return "ia64/itanium2";
        default:
            return "ia64/ia64";
    }
}


/* all the ops are handled via userspace for IA64 perfmon */

static int using_perfmon;

int perfmon_init(struct oprofile_operations *ops)
{
    int ret = pfm_register_buffer_fmt(&oprofile_fmt);
    if (ret)
        return -ENODEV;

    ops->cpu_type = get_cpu_type();
    ops->start = perfmon_start;
    ops->stop = perfmon_stop;
    using_perfmon = 1;
    printk(KERN_INFO "oprofile: using perfmon.\n");
    return 0;
}


void perfmon_exit(void)
{
    if (!using_perfmon)
        return;

    pfm_unregister_buffer_fmt(oprofile_fmt.fmt_uuid);
}