summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/perf_event.c
blob: 2343c218b8f991224e0d3fb44e6838354cfb7e7e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
/*
 * 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/kvm_host.h>
#include <linux/percpu.h>
#include <linux/export.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);

static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs)
{
	struct stack_frame *stack = (struct stack_frame *) regs->gprs[15];

	if (!stack)
		return NULL;

	return (struct kvm_s390_sie_block *) stack->empty1[0];
}

static bool is_in_guest(struct pt_regs *regs)
{
	if (user_mode(regs))
		return false;
#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
	return instruction_pointer(regs) == (unsigned long) &sie_exit;
#else
	return false;
#endif
}

static unsigned long guest_is_user_mode(struct pt_regs *regs)
{
	return sie_block(regs)->gpsw.mask & PSW_MASK_PSTATE;
}

static unsigned long instruction_pointer_guest(struct pt_regs *regs)
{
	return sie_block(regs)->gpsw.addr & PSW_ADDR_INSN;
}

unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
	return is_in_guest(regs) ? instruction_pointer_guest(regs)
				 : instruction_pointer(regs);
}

static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
{
	return guest_is_user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
					: PERF_RECORD_MISC_GUEST_KERNEL;
}

unsigned long perf_misc_flags(struct pt_regs *regs)
{
	if (is_in_guest(regs))
		return perf_misc_guest_flags(regs);

	return user_mode(regs) ? PERF_RECORD_MISC_USER
			       : PERF_RECORD_MISC_KERNEL;
}

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);

	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);
}