1/*
  2 * Performance event support for s390x
  3 *
  4 *  Copyright IBM Corp. 2012
  5 *  Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License (version 2 only)
  9 * as published by the Free Software Foundation.
 10 */
 11#define KMSG_COMPONENT	"perf"
 12#define pr_fmt(fmt)	KMSG_COMPONENT ": " fmt
 13
 14#include <linux/kernel.h>
 15#include <linux/perf_event.h>
 16#include <linux/percpu.h>
 17#include <linux/export.h>
 18#include <asm/irq.h>
 19#include <asm/cpu_mf.h>
 20#include <asm/lowcore.h>
 21#include <asm/processor.h>
 22
 23const char *perf_pmu_name(void)
 24{
 25	if (cpum_cf_avail() || cpum_sf_avail())
 26		return "CPU-measurement facilities (CPUMF)";
 27	return "pmu";
 28}
 29EXPORT_SYMBOL(perf_pmu_name);
 30
 31int perf_num_counters(void)
 32{
 33	int num = 0;
 34
 35	if (cpum_cf_avail())
 36		num += PERF_CPUM_CF_MAX_CTR;
 37
 38	return num;
 39}
 40EXPORT_SYMBOL(perf_num_counters);
 41
 42void perf_event_print_debug(void)
 43{
 44	struct cpumf_ctr_info cf_info;
 45	unsigned long flags;
 46	int cpu;
 47
 48	if (!cpum_cf_avail())
 49		return;
 50
 51	local_irq_save(flags);
 52
 53	cpu = smp_processor_id();
 54	memset(&cf_info, 0, sizeof(cf_info));
 55	if (!qctri(&cf_info)) {
 56		pr_info("CPU[%i] CPUM_CF: ver=%u.%u A=%04x E=%04x C=%04x\n",
 57			cpu, cf_info.cfvn, cf_info.csvn,
 58			cf_info.auth_ctl, cf_info.enable_ctl, cf_info.act_ctl);
 59		print_hex_dump_bytes("CPUMF Query: ", DUMP_PREFIX_OFFSET,
 60				     &cf_info, sizeof(cf_info));
 61	}
 62
 63	local_irq_restore(flags);
 64}
 65
 66/* See also arch/s390/kernel/traps.c */
 67static unsigned long __store_trace(struct perf_callchain_entry *entry,
 68				   unsigned long sp,
 69				   unsigned long low, unsigned long high)
 70{
 71	struct stack_frame *sf;
 72	struct pt_regs *regs;
 73
 74	while (1) {
 75		sp = sp & PSW_ADDR_INSN;
 76		if (sp < low || sp > high - sizeof(*sf))
 77			return sp;
 78		sf = (struct stack_frame *) sp;
 79		perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 80		/* Follow the backchain. */
 81		while (1) {
 82			low = sp;
 83			sp = sf->back_chain & PSW_ADDR_INSN;
 84			if (!sp)
 85				break;
 86			if (sp <= low || sp > high - sizeof(*sf))
 87				return sp;
 88			sf = (struct stack_frame *) sp;
 89			perf_callchain_store(entry,
 90					     sf->gprs[8] & PSW_ADDR_INSN);
 91		}
 92		/* Zero backchain detected, check for interrupt frame. */
 93		sp = (unsigned long) (sf + 1);
 94		if (sp <= low || sp > high - sizeof(*regs))
 95			return sp;
 96		regs = (struct pt_regs *) sp;
 97		perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 98		low = sp;
 99		sp = regs->gprs[15];
100	}
101}
102
103void perf_callchain_kernel(struct perf_callchain_entry *entry,
104			   struct pt_regs *regs)
105{
106	unsigned long head;
107	struct stack_frame *head_sf;
108
109	if (user_mode(regs))
110		return;
111
112	head = regs->gprs[15];
113	head_sf = (struct stack_frame *) head;
114
115	if (!head_sf || !head_sf->back_chain)
116		return;
117
118	head = head_sf->back_chain;
119	head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
120			     S390_lowcore.async_stack);
121
122	__store_trace(entry, head, S390_lowcore.thread_info,
123		      S390_lowcore.thread_info + THREAD_SIZE);
124}