1 files changed, 182 insertions, 0 deletions
diff --git a/sys/kern/kern_pmc.c b/sys/kern/kern_pmc.c
new file mode 100644
index 000000000000..4e3fe75e490e
--- /dev/null
+++ b/sys/kern/kern_pmc.c
@@ -0,0 +1,182 @@
+/*-
+ * Copyright (c) 2003-2008 Joseph Koshy
+ * Copyright (c) 2007 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * Portions of this software were developed by A. Joseph Koshy under
+ * sponsorship from the FreeBSD Foundation and Google, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_hwpmc_hooks.h"
+
+#include <sys/types.h>
+#include <sys/pmc.h>
+#include <sys/pmckern.h>
+#include <sys/smp.h>
+
+#ifdef	HWPMC_HOOKS
+#define	PMC_KERNEL_VERSION	PMC_VERSION
+#else
+#define	PMC_KERNEL_VERSION	0
+#endif
+
+const int pmc_kernel_version = PMC_KERNEL_VERSION;
+
+/* Hook variable. */
+int (*pmc_hook)(struct thread *td, int function, void *arg) = NULL;
+
+/* Interrupt handler */
+int (*pmc_intr)(int cpu, struct trapframe *tf) = NULL;
+
+/* Bitmask of CPUs requiring servicing at hardclock time */
+volatile cpumask_t pmc_cpumask;
+
+/*
+ * A global count of SS mode PMCs.  When non-zero, this means that
+ * we have processes that are sampling the system as a whole.
+ */
+volatile int pmc_ss_count;
+
+/*
+ * Since PMC(4) may not be loaded in the current kernel, the
+ * convention followed is that a non-NULL value of 'pmc_hook' implies
+ * the presence of this kernel module.
+ *
+ * This requires us to protect 'pmc_hook' with a
+ * shared (sx) lock -- thus making the process of calling into PMC(4)
+ * somewhat more expensive than a simple 'if' check and indirect call.
+ */
+struct sx pmc_sx;
+
+static void
+pmc_init_sx(void)
+{
+	sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS);
+}
+
+SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL);
+
+/*
+ * Helper functions.
+ */
+
+/*
+ * A note on the CPU numbering scheme used by the hwpmc(4) driver.
+ *
+ * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1].
+ * CPUs could be numbered "sparsely" in this range; the predicate
+ * `pmc_cpu_is_present()' is used to test whether a given CPU is
+ * physically present.
+ *
+ * Further, a CPU that is physically present may be administratively
+ * disabled or otherwise unavailable for use by hwpmc(4).  The
+ * `pmc_cpu_is_active()' predicate tests for CPU usability.  An
+ * "active" CPU participates in thread scheduling and can field
+ * interrupts raised by PMC hardware.
+ *
+ * On systems with hyperthreaded CPUs, multiple logical CPUs may share
+ * PMC hardware resources.  For such processors one logical CPU is
+ * denoted as the primary owner of the in-CPU PMC resources. The
+ * pmc_cpu_is_primary() predicate is used to distinguish this primary
+ * CPU from the others.
+ */
+
+int
+pmc_cpu_is_active(int cpu)
+{
+#ifdef	SMP
+	return (pmc_cpu_is_present(cpu) &&
+	    (hlt_cpus_mask & (1 << cpu)) == 0);
+#else
+	return (1);
+#endif
+}
+
+/* Deprecated. */
+int
+pmc_cpu_is_disabled(int cpu)
+{
+	return (!pmc_cpu_is_active(cpu));
+}
+
+int
+pmc_cpu_is_present(int cpu)
+{
+#ifdef	SMP
+	return (!CPU_ABSENT(cpu));
+#else
+	return (1);
+#endif
+}
+
+int
+pmc_cpu_is_primary(int cpu)
+{
+#ifdef	SMP
+	return ((logical_cpus_mask & (1 << cpu)) == 0);
+#else
+	return (1);
+#endif
+}
+
+
+/*
+ * Return the maximum CPU number supported by the system.  The return
+ * value is used for scaling internal data structures and for runtime
+ * checks.
+ */
+unsigned int
+pmc_cpu_max(void)
+{
+#ifdef	SMP
+	return (mp_maxid+1);
+#else
+	return (1);
+#endif
+}
+
+#ifdef	INVARIANTS
+
+/*
+ * Return the count of CPUs in the `active' state in the system.
+ */
+int
+pmc_cpu_max_active(void)
+{
+#ifdef	SMP
+	/*
+	 * When support for CPU hot-plugging is added to the kernel,
+	 * this function would change to return the current number
+	 * of "active" CPUs.
+	 */
+	return (mp_ncpus);
+#else
+	return (1);
+#endif
+}
+
+#endif