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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * arch/powerpc/kernel/pmc.c
- *
- * Copyright (C) 2004 David Gibson, IBM Corporation.
- * Includes code formerly from arch/ppc/kernel/perfmon.c:
- * Author: Andy Fleming
- * Copyright (c) 2004 Freescale Semiconductor, Inc
- */
- #include <linux/errno.h>
- #include <linux/bug.h>
- #include <linux/spinlock.h>
- #include <linux/export.h>
- #include <asm/processor.h>
- #include <asm/cputable.h>
- #include <asm/pmc.h>
- #ifndef MMCR0_PMAO
- #define MMCR0_PMAO 0
- #endif
- static void dummy_perf(struct pt_regs *regs)
- {
- #if defined(CONFIG_FSL_EMB_PERFMON)
- mtpmr(PMRN_PMGC0, mfpmr(PMRN_PMGC0) & ~PMGC0_PMIE);
- #elif defined(CONFIG_PPC64) || defined(CONFIG_PPC_BOOK3S_32)
- if (cur_cpu_spec->pmc_type == PPC_PMC_IBM)
- mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~(MMCR0_PMXE|MMCR0_PMAO));
- #else
- mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_PMXE);
- #endif
- }
- static DEFINE_RAW_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;
- raw_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 ? new_perf_irq : dummy_perf;
- out:
- raw_spin_unlock(&pmc_owner_lock);
- return err;
- }
- EXPORT_SYMBOL_GPL(reserve_pmc_hardware);
- void release_pmc_hardware(void)
- {
- raw_spin_lock(&pmc_owner_lock);
- WARN_ON(! pmc_owner_caller);
- pmc_owner_caller = NULL;
- perf_irq = dummy_perf;
- raw_spin_unlock(&pmc_owner_lock);
- }
- EXPORT_SYMBOL_GPL(release_pmc_hardware);
- #ifdef CONFIG_PPC64
- void power4_enable_pmcs(void)
- {
- unsigned long hid0;
- hid0 = mfspr(SPRN_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" (SPRN_HID0), "0" (hid0):
- "memory");
- }
- #endif /* CONFIG_PPC64 */
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