arch/ppc/kernel/perfmon.c

   1 /* kernel/perfmon.c
   2  * PPC 32 Performance Monitor Infrastructure
   3  *
   4  * Author: Andy Fleming
   5  * Copyright (c) 2004 Freescale Semiconductor, Inc
   6  *
   7  *  This program is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU General Public License
   9  *  as published by the Free Software Foundation; either version
  10  *  2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/errno.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/stddef.h>
  18 #include <linux/unistd.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/slab.h>
  21 #include <linux/user.h>
  22 #include <linux/a.out.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/config.h>
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/prctl.h>
  28
  29 #include <asm/pgtable.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/system.h>
  32 #include <asm/io.h>
  33 #include <asm/reg.h>
  34 #include <asm/xmon.h>
  35
  36 /* A lock to regulate grabbing the interrupt */
  37 DEFINE_SPINLOCK(perfmon_lock);
  38
  39 #ifdef CONFIG_FSL_BOOKE
  40 static void dummy_perf(struct pt_regs *regs)
  41 {
  42         unsigned int pmgc0 = mfpmr(PMRN_PMGC0);
  43
  44         pmgc0 &= ~PMGC0_PMIE;
  45         mtpmr(PMRN_PMGC0, pmgc0);
  46 }
  47
  48 #else
  49 /* Ensure exceptions are disabled */
  50
  51 static void dummy_perf(struct pt_regs *regs)
  52 {
  53         unsigned int mmcr0 = mfspr(SPRN_MMCR0);
  54
  55         mmcr0 &= ~MMCR0_PMXE;
  56         mtspr(SPRN_MMCR0, mmcr0);
  57 }
  58 #endif
  59
  60 void (*perf_irq)(struct pt_regs *) = dummy_perf;
  61
  62 /* Grab the interrupt, if it's free.
  63  * Returns 0 on success, -1 if the interrupt is taken already */
  64 int request_perfmon_irq(void (*handler)(struct pt_regs *))
  65 {
  66         int err = 0;
  67
  68         spin_lock(&perfmon_lock);
  69
  70         if (perf_irq == dummy_perf)
  71                 perf_irq = handler;
  72         else {
  73                 pr_info("perfmon irq already handled by %p\n", perf_irq);
  74                 err = -1;
  75         }
  76
  77         spin_unlock(&perfmon_lock);
  78
  79         return err;
  80 }
  81
  82 void free_perfmon_irq(void)
  83 {
  84         spin_lock(&perfmon_lock);
  85
  86         perf_irq = dummy_perf;
  87
  88         spin_unlock(&perfmon_lock);
  89 }
  90
  91 EXPORT_SYMBOL(perf_irq);
  92 EXPORT_SYMBOL(request_perfmon_irq);
  93 EXPORT_SYMBOL(free_perfmon_irq);