[S390] perf: add support for s390x CPU counters

Add a perf PMU to access the CPU-measurement counter facility CPUM CF.
CPUM CF provides multiple counter sets for measuring generic,
problem-state, and crypto activaties.  Also an extended counter set for
the IBM System z10 and IBM z196 mainframes is available.

Counters from the basic and problem-state counter set are mapped to
generic perf hardware events.  Other counters are accessible through
raw events.

For a list of available counter sets and counters, see:

  - The Load-Program-Parameter and the CPU-Measurement Facilities (SA23-2260)
  - The CPU-Measurement Facility Extended Counters Definition for
    z10 and z196 (SA23-2261)

Reviewed-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 125 insertions, 0 deletions

diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
new file mode 100644
index 000000000000..609f985198cf
--- /dev/null
+++ b/arch/s390/kernel/perf_event.c
@@ -0,0 +1,125 @@
+/*
+ * Performance event support for s390x
+ *
+ *  Copyright IBM Corp. 2012
+ *  Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ */
+#define KMSG_COMPONENT	"perf"
+#define pr_fmt(fmt)	KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/perf_event.h>
+#include <linux/percpu.h>
+#include <linux/export.h>
+#include <asm/system.h>
+#include <asm/irq.h>
+#include <asm/cpu_mf.h>
+#include <asm/lowcore.h>
+#include <asm/processor.h>
+
+const char *perf_pmu_name(void)
+{
+	if (cpum_cf_avail() || cpum_sf_avail())
+		return "CPU-measurement facilities (CPUMF)";
+	return "pmu";
+}
+EXPORT_SYMBOL(perf_pmu_name);
+
+int perf_num_counters(void)
+{
+	int num = 0;
+
+	if (cpum_cf_avail())
+		num += PERF_CPUM_CF_MAX_CTR;
+
+	return num;
+}
+EXPORT_SYMBOL(perf_num_counters);
+
+void perf_event_print_debug(void)
+{
+	struct cpumf_ctr_info cf_info;
+	unsigned long flags;
+	int cpu;
+
+	if (!cpum_cf_avail())
+		return;
+
+	local_irq_save(flags);
+
+	cpu = smp_processor_id();
+	memset(&cf_info, 0, sizeof(cf_info));
+	if (!qctri(&cf_info)) {
+		pr_info("CPU[%i] CPUM_CF: ver=%u.%u A=%04x E=%04x C=%04x\n",
+			cpu, cf_info.cfvn, cf_info.csvn,
+			cf_info.auth_ctl, cf_info.enable_ctl, cf_info.act_ctl);
+		print_hex_dump_bytes("CPUMF Query: ", DUMP_PREFIX_OFFSET,
+				     &cf_info, sizeof(cf_info));
+	}
+
+	local_irq_restore(flags);
+}
+
+/* See also arch/s390/kernel/traps.c */
+static unsigned long __store_trace(struct perf_callchain_entry *entry,
+				   unsigned long sp,
+				   unsigned long low, unsigned long high)
+{
+	struct stack_frame *sf;
+	struct pt_regs *regs;
+
+	while (1) {
+		sp = sp & PSW_ADDR_INSN;
+		if (sp < low || sp > high - sizeof(*sf))
+			return sp;
+		sf = (struct stack_frame *) sp;
+		perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
+		/* Follow the backchain. */
+		while (1) {
+			low = sp;
+			sp = sf->back_chain & PSW_ADDR_INSN;
+			if (!sp)
+				break;
+			if (sp <= low || sp > high - sizeof(*sf))
+				return sp;
+			sf = (struct stack_frame *) sp;
+			perf_callchain_store(entry,
+					     sf->gprs[8] & PSW_ADDR_INSN);
+		}
+		/* Zero backchain detected, check for interrupt frame. */
+		sp = (unsigned long) (sf + 1);
+		if (sp <= low || sp > high - sizeof(*regs))
+			return sp;
+		regs = (struct pt_regs *) sp;
+		perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
+		low = sp;
+		sp = regs->gprs[15];
+	}
+}
+
+void perf_callchain_kernel(struct perf_callchain_entry *entry,
+			   struct pt_regs *regs)
+{
+	unsigned long head;
+	struct stack_frame *head_sf;
+
+	if (user_mode(regs))
+		return;
+
+	head = regs->gprs[15];
+	head_sf = (struct stack_frame *) head;
+
+	if (!head_sf || !head_sf->back_chain)
+		return;
+
+	head = head_sf->back_chain;
+	head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
+			     S390_lowcore.async_stack);
+
+	__store_trace(entry, head, S390_lowcore.thread_info,
+		      S390_lowcore.thread_info + THREAD_SIZE);
+}