1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Hypervisor filesystem for Linux on s390
4 *
5 * Diag 0C implementation
6 *
7 * Copyright IBM Corp. 2014
8 */
9
10#include <linux/slab.h>
11#include <linux/cpu.h>
12#include <asm/diag.h>
13#include <asm/hypfs.h>
14#include "hypfs.h"
15
16#define DBFS_D0C_HDR_VERSION 0
17
18/*
19 * Get hypfs_diag0c_entry from CPU vector and store diag0c data
20 */
21static void diag0c_fn(void *data)
22{
23	diag_stat_inc(DIAG_STAT_X00C);
24	diag_amode31_ops.diag0c(((void **)data)[smp_processor_id()]);
25}
26
27/*
28 * Allocate buffer and store diag 0c data
29 */
30static void *diag0c_store(unsigned int *count)
31{
32	struct hypfs_diag0c_data *diag0c_data;
33	unsigned int cpu_count, cpu, i;
34	void **cpu_vec;
35
36	cpus_read_lock();
37	cpu_count = num_online_cpus();
38	cpu_vec = kmalloc_array(num_possible_cpus(), sizeof(*cpu_vec),
39				GFP_KERNEL);
40	if (!cpu_vec)
41		goto fail_unlock_cpus;
42	/* Note: Diag 0c needs 8 byte alignment and real storage */
43	diag0c_data = kzalloc(struct_size(diag0c_data, entry, cpu_count),
44			      GFP_KERNEL | GFP_DMA);
45	if (!diag0c_data)
46		goto fail_kfree_cpu_vec;
47	i = 0;
48	/* Fill CPU vector for each online CPU */
49	for_each_online_cpu(cpu) {
50		diag0c_data->entry[i].cpu = cpu;
51		cpu_vec[cpu] = &diag0c_data->entry[i++];
52	}
53	/* Collect data all CPUs */
54	on_each_cpu(diag0c_fn, cpu_vec, 1);
55	*count = cpu_count;
56	kfree(cpu_vec);
57	cpus_read_unlock();
58	return diag0c_data;
59
60fail_kfree_cpu_vec:
61	kfree(cpu_vec);
62fail_unlock_cpus:
63	cpus_read_unlock();
64	return ERR_PTR(-ENOMEM);
65}
66
67/*
68 * Hypfs DBFS callback: Free diag 0c data
69 */
70static void dbfs_diag0c_free(const void *data)
71{
72	kfree(data);
73}
74
75/*
76 * Hypfs DBFS callback: Create diag 0c data
77 */
78static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
79{
80	struct hypfs_diag0c_data *diag0c_data;
81	unsigned int count;
82
83	diag0c_data = diag0c_store(&count);
84	if (IS_ERR(diag0c_data))
85		return PTR_ERR(diag0c_data);
86	memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
87	store_tod_clock_ext((union tod_clock *)diag0c_data->hdr.tod_ext);
88	diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
89	diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
90	diag0c_data->hdr.count = count;
91	*data = diag0c_data;
92	*data_free_ptr = diag0c_data;
93	*size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
94	return 0;
95}
96
97/*
98 * Hypfs DBFS file structure
99 */
100static struct hypfs_dbfs_file dbfs_file_0c = {
101	.name		= "diag_0c",
102	.data_create	= dbfs_diag0c_create,
103	.data_free	= dbfs_diag0c_free,
104};
105
106/*
107 * Initialize diag 0c interface for z/VM
108 */
109int __init hypfs_diag0c_init(void)
110{
111	if (!MACHINE_IS_VM)
112		return 0;
113	hypfs_dbfs_create_file(&dbfs_file_0c);
114	return 0;
115}
116
117/*
118 * Shutdown diag 0c interface for z/VM
119 */
120void hypfs_diag0c_exit(void)
121{
122	if (!MACHINE_IS_VM)
123		return;
124	hypfs_dbfs_remove_file(&dbfs_file_0c);
125}
126