hvCall_inst.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (C) 2006 Mike Kravetz IBM Corporation
  4 *
  5 * Hypervisor Call Instrumentation
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/percpu.h>
 10#include <linux/debugfs.h>
 11#include <linux/seq_file.h>
 12#include <linux/cpumask.h>
 13#include <asm/hvcall.h>
 14#include <asm/firmware.h>
 15#include <asm/cputable.h>
 16#include <asm/trace.h>
 17#include <asm/machdep.h>
 18
 19/* For hcall instrumentation. One structure per-hcall, per-CPU */
 20struct hcall_stats {
 21	unsigned long	num_calls;	/* number of calls (on this CPU) */
 22	unsigned long	tb_total;	/* total wall time (mftb) of calls. */
 23	unsigned long	purr_total;	/* total cpu time (PURR) of calls. */
 24	unsigned long	tb_start;
 25	unsigned long	purr_start;
 26};
 27#define HCALL_STAT_ARRAY_SIZE	((MAX_HCALL_OPCODE >> 2) + 1)
 28
 29static DEFINE_PER_CPU(struct hcall_stats[HCALL_STAT_ARRAY_SIZE], hcall_stats);
 30
 31/*
 32 * Routines for displaying the statistics in debugfs
 33 */
 34static void *hc_start(struct seq_file *m, loff_t *pos)
 35{
 36	if ((int)*pos < (HCALL_STAT_ARRAY_SIZE-1))
 37		return (void *)(unsigned long)(*pos + 1);
 38
 39	return NULL;
 40}
 41
 42static void *hc_next(struct seq_file *m, void *p, loff_t * pos)
 43{
 44	++*pos;
 45
 46	return hc_start(m, pos);
 47}
 48
 49static void hc_stop(struct seq_file *m, void *p)
 50{
 51}
 52
 53static int hc_show(struct seq_file *m, void *p)
 54{
 55	unsigned long h_num = (unsigned long)p;
 56	struct hcall_stats *hs = m->private;
 57
 58	if (hs[h_num].num_calls) {
 59		if (cpu_has_feature(CPU_FTR_PURR))
 60			seq_printf(m, "%lu %lu %lu %lu\n", h_num<<2,
 61				   hs[h_num].num_calls,
 62				   hs[h_num].tb_total,
 63				   hs[h_num].purr_total);
 64		else
 65			seq_printf(m, "%lu %lu %lu\n", h_num<<2,
 66				   hs[h_num].num_calls,
 67				   hs[h_num].tb_total);
 68	}
 69
 70	return 0;
 71}
 72
 73static const struct seq_operations hcall_inst_sops = {
 74        .start = hc_start,
 75        .next  = hc_next,
 76        .stop  = hc_stop,
 77        .show  = hc_show
 78};
 79
 80DEFINE_SEQ_ATTRIBUTE(hcall_inst);
 81
 82#define	HCALL_ROOT_DIR		"hcall_inst"
 83#define CPU_NAME_BUF_SIZE	32
 84
 85
 86static void probe_hcall_entry(void *ignored, unsigned long opcode, unsigned long *args)
 87{
 88	struct hcall_stats *h;
 89
 90	if (opcode > MAX_HCALL_OPCODE)
 91		return;
 92
 93	h = this_cpu_ptr(&hcall_stats[opcode / 4]);
 94	h->tb_start = mftb();
 95	h->purr_start = mfspr(SPRN_PURR);
 96}
 97
 98static void probe_hcall_exit(void *ignored, unsigned long opcode, long retval,
 99			     unsigned long *retbuf)
100{
101	struct hcall_stats *h;
102
103	if (opcode > MAX_HCALL_OPCODE)
104		return;
105
106	h = this_cpu_ptr(&hcall_stats[opcode / 4]);
107	h->num_calls++;
108	h->tb_total += mftb() - h->tb_start;
109	h->purr_total += mfspr(SPRN_PURR) - h->purr_start;
110}
111
112static int __init hcall_inst_init(void)
113{
114	struct dentry *hcall_root;
115	char cpu_name_buf[CPU_NAME_BUF_SIZE];
116	int cpu;
117
118	if (!firmware_has_feature(FW_FEATURE_LPAR))
119		return 0;
120
121	if (register_trace_hcall_entry(probe_hcall_entry, NULL))
122		return -EINVAL;
123
124	if (register_trace_hcall_exit(probe_hcall_exit, NULL)) {
125		unregister_trace_hcall_entry(probe_hcall_entry, NULL);
126		return -EINVAL;
127	}
128
129	hcall_root = debugfs_create_dir(HCALL_ROOT_DIR, NULL);
130
131	for_each_possible_cpu(cpu) {
132		snprintf(cpu_name_buf, CPU_NAME_BUF_SIZE, "cpu%d", cpu);
133		debugfs_create_file(cpu_name_buf, 0444, hcall_root,
134				    per_cpu(hcall_stats, cpu),
135				    &hcall_inst_fops);
136	}
137
138	return 0;
139}
140machine_device_initcall(pseries, hcall_inst_init);