68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
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/*
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* linux/arch/ppc64/kernel/pmc.c
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*
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* Copyright (C) 2004 David Gibson, IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <asm/processor.h>
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#include <asm/pmc.h>
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/* Ensure exceptions are disabled */
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static void dummy_perf(struct pt_regs *regs)
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{
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unsigned int mmcr0 = mfspr(SPRN_MMCR0);
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mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO);
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mtspr(SPRN_MMCR0, mmcr0);
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}
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static spinlock_t pmc_owner_lock = SPIN_LOCK_UNLOCKED;
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static void *pmc_owner_caller; /* mostly for debugging */
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perf_irq_t perf_irq = dummy_perf;
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int reserve_pmc_hardware(perf_irq_t new_perf_irq)
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{
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int err = 0;
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spin_lock(&pmc_owner_lock);
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if (pmc_owner_caller) {
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printk(KERN_WARNING "reserve_pmc_hardware: "
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"PMC hardware busy (reserved by caller %p)\n",
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pmc_owner_caller);
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err = -EBUSY;
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goto out;
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}
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pmc_owner_caller = __builtin_return_address(0);
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perf_irq = new_perf_irq ? : dummy_perf;
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out:
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spin_unlock(&pmc_owner_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
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void release_pmc_hardware(void)
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{
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spin_lock(&pmc_owner_lock);
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WARN_ON(! pmc_owner_caller);
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pmc_owner_caller = NULL;
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perf_irq = dummy_perf;
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spin_unlock(&pmc_owner_lock);
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}
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EXPORT_SYMBOL_GPL(release_pmc_hardware);
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