/* * linux/arch/ppc64/kernel/pmc.c * * Copyright (C) 2004 David Gibson, IBM Corporation. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/config.h> #include <linux/errno.h> #include <linux/spinlock.h> #include <linux/module.h> #include <asm/processor.h> #include <asm/pmc.h> /* Ensure exceptions are disabled */ static void dummy_perf(struct pt_regs *regs) { unsigned int mmcr0 = mfspr(SPRN_MMCR0); mmcr0 &= ~(MMCR0_PMXE|MMCR0_PMAO); mtspr(SPRN_MMCR0, mmcr0); } static DEFINE_SPINLOCK(pmc_owner_lock); static void *pmc_owner_caller; /* mostly for debugging */ perf_irq_t perf_irq = dummy_perf; int reserve_pmc_hardware(perf_irq_t new_perf_irq) { int err = 0; spin_lock(&pmc_owner_lock); if (pmc_owner_caller) { printk(KERN_WARNING "reserve_pmc_hardware: " "PMC hardware busy (reserved by caller %p)\n", pmc_owner_caller); err = -EBUSY; goto out; } pmc_owner_caller = __builtin_return_address(0); perf_irq = new_perf_irq ? : dummy_perf; out: spin_unlock(&pmc_owner_lock); return err; } EXPORT_SYMBOL_GPL(reserve_pmc_hardware); void release_pmc_hardware(void) { spin_lock(&pmc_owner_lock); WARN_ON(! pmc_owner_caller); pmc_owner_caller = NULL; perf_irq = dummy_perf; spin_unlock(&pmc_owner_lock); } EXPORT_SYMBOL_GPL(release_pmc_hardware); void power4_enable_pmcs(void) { unsigned long hid0; hid0 = mfspr(HID0); hid0 |= 1UL << (63 - 20); /* POWER4 requires the following sequence */ asm volatile( "sync\n" "mtspr %1, %0\n" "mfspr %0, %1\n" "mfspr %0, %1\n" "mfspr %0, %1\n" "mfspr %0, %1\n" "mfspr %0, %1\n" "mfspr %0, %1\n" "isync" : "=&r" (hid0) : "i" (HID0), "0" (hid0): "memory"); }