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 */
20 struct 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 
29 DEFINE_PER_CPU(struct hcall_stats[HCALL_STAT_ARRAY_SIZE], hcall_stats);
30 
31 /*
32  * Routines for displaying the statistics in debugfs
33  */
34 static 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 
42 static void *hc_next(struct seq_file *m, void *p, loff_t * pos)
43 {
44 	++*pos;
45 
46 	return hc_start(m, pos);
47 }
48 
49 static void hc_stop(struct seq_file *m, void *p)
50 {
51 }
52 
53 static 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 
73 static const struct seq_operations hcall_inst_seq_ops = {
74         .start = hc_start,
75         .next  = hc_next,
76         .stop  = hc_stop,
77         .show  = hc_show
78 };
79 
80 static int hcall_inst_seq_open(struct inode *inode, struct file *file)
81 {
82 	int rc;
83 	struct seq_file *seq;
84 
85 	rc = seq_open(file, &hcall_inst_seq_ops);
86 	seq = file->private_data;
87 	seq->private = file_inode(file)->i_private;
88 
89 	return rc;
90 }
91 
92 static const struct file_operations hcall_inst_seq_fops = {
93 	.open = hcall_inst_seq_open,
94 	.read = seq_read,
95 	.llseek = seq_lseek,
96 	.release = seq_release,
97 };
98 
99 #define	HCALL_ROOT_DIR		"hcall_inst"
100 #define CPU_NAME_BUF_SIZE	32
101 
102 
103 static void probe_hcall_entry(void *ignored, unsigned long opcode, unsigned long *args)
104 {
105 	struct hcall_stats *h;
106 
107 	if (opcode > MAX_HCALL_OPCODE)
108 		return;
109 
110 	h = this_cpu_ptr(&hcall_stats[opcode / 4]);
111 	h->tb_start = mftb();
112 	h->purr_start = mfspr(SPRN_PURR);
113 }
114 
115 static void probe_hcall_exit(void *ignored, unsigned long opcode, long retval,
116 			     unsigned long *retbuf)
117 {
118 	struct hcall_stats *h;
119 
120 	if (opcode > MAX_HCALL_OPCODE)
121 		return;
122 
123 	h = this_cpu_ptr(&hcall_stats[opcode / 4]);
124 	h->num_calls++;
125 	h->tb_total += mftb() - h->tb_start;
126 	h->purr_total += mfspr(SPRN_PURR) - h->purr_start;
127 }
128 
129 static int __init hcall_inst_init(void)
130 {
131 	struct dentry *hcall_root;
132 	char cpu_name_buf[CPU_NAME_BUF_SIZE];
133 	int cpu;
134 
135 	if (!firmware_has_feature(FW_FEATURE_LPAR))
136 		return 0;
137 
138 	if (register_trace_hcall_entry(probe_hcall_entry, NULL))
139 		return -EINVAL;
140 
141 	if (register_trace_hcall_exit(probe_hcall_exit, NULL)) {
142 		unregister_trace_hcall_entry(probe_hcall_entry, NULL);
143 		return -EINVAL;
144 	}
145 
146 	hcall_root = debugfs_create_dir(HCALL_ROOT_DIR, NULL);
147 
148 	for_each_possible_cpu(cpu) {
149 		snprintf(cpu_name_buf, CPU_NAME_BUF_SIZE, "cpu%d", cpu);
150 		debugfs_create_file(cpu_name_buf, 0444, hcall_root,
151 				    per_cpu(hcall_stats, cpu),
152 				    &hcall_inst_seq_fops);
153 	}
154 
155 	return 0;
156 }
157 machine_device_initcall(pseries, hcall_inst_init);
158