1 files changed, 67 insertions, 0 deletions
diff --git a/arch/ppc64/kernel/pmc.c b/arch/ppc64/kernel/pmc.c
new file mode 100644
index 000000000000..67be773f9c00
--- /dev/null
+++ b/arch/ppc64/kernel/pmc.c
@@ -0,0 +1,67 @@
+/*
+ *  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 spinlock_t pmc_owner_lock = SPIN_LOCK_UNLOCKED;
+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);