LXR linux/arch/powerpc/kernel/pmc.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  arch/powerpc/kernel/pmc.c
   4 *
   5 *  Copyright (C) 2004 David Gibson, IBM Corporation.
   6 *  Includes code formerly from arch/ppc/kernel/perfmon.c:
   7 *    Author: Andy Fleming
   8 *    Copyright (c) 2004 Freescale Semiconductor, Inc
   9 */
  10
  11#include <linux/errno.h>
  12#include <linux/bug.h>
  13#include <linux/spinlock.h>
  14#include <linux/export.h>
  15
  16#include <asm/processor.h>
  17#include <asm/cputable.h>
  18#include <asm/pmc.h>
  19
  20#ifndef MMCR0_PMAO
  21#define MMCR0_PMAO      0
  22#endif
  23
  24static void dummy_perf(struct pt_regs *regs)
  25{
  26#if defined(CONFIG_FSL_EMB_PERFMON)
  27        mtpmr(PMRN_PMGC0, mfpmr(PMRN_PMGC0) & ~PMGC0_PMIE);
  28#elif defined(CONFIG_PPC64) || defined(CONFIG_PPC_BOOK3S_32)
  29        if (cur_cpu_spec->pmc_type == PPC_PMC_IBM)
  30                mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~(MMCR0_PMXE|MMCR0_PMAO));
  31#else
  32        mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_PMXE);
  33#endif
  34}
  35
  36
  37static DEFINE_RAW_SPINLOCK(pmc_owner_lock);
  38static void *pmc_owner_caller; /* mostly for debugging */
  39perf_irq_t perf_irq = dummy_perf;
  40
  41int reserve_pmc_hardware(perf_irq_t new_perf_irq)
  42{
  43        int err = 0;
  44
  45        raw_spin_lock(&pmc_owner_lock);
  46
  47        if (pmc_owner_caller) {
  48                printk(KERN_WARNING "reserve_pmc_hardware: "
  49                       "PMC hardware busy (reserved by caller %p)\n",
  50                       pmc_owner_caller);
  51                err = -EBUSY;
  52                goto out;
  53        }
  54
  55        pmc_owner_caller = __builtin_return_address(0);
  56        perf_irq = new_perf_irq ? new_perf_irq : dummy_perf;
  57
  58 out:
  59        raw_spin_unlock(&pmc_owner_lock);
  60        return err;
  61}
  62EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
  63
  64void release_pmc_hardware(void)
  65{
  66        raw_spin_lock(&pmc_owner_lock);
  67
  68        WARN_ON(! pmc_owner_caller);
  69
  70        pmc_owner_caller = NULL;
  71        perf_irq = dummy_perf;
  72
  73        raw_spin_unlock(&pmc_owner_lock);
  74}
  75EXPORT_SYMBOL_GPL(release_pmc_hardware);
  76
  77#ifdef CONFIG_PPC64
  78void power4_enable_pmcs(void)
  79{
  80        unsigned long hid0;
  81
  82        hid0 = mfspr(SPRN_HID0);
  83        hid0 |= 1UL << (63 - 20);
  84
  85        /* POWER4 requires the following sequence */
  86        asm volatile(
  87                "sync\n"
  88                "mtspr     %1, %0\n"
  89                "mfspr     %0, %1\n"
  90                "mfspr     %0, %1\n"
  91                "mfspr     %0, %1\n"
  92                "mfspr     %0, %1\n"
  93                "mfspr     %0, %1\n"
  94                "mfspr     %0, %1\n"
  95                "isync" : "=&r" (hid0) : "i" (SPRN_HID0), "0" (hid0):
  96                "memory");
  97}
  98#endif /* CONFIG_PPC64 */
  99