1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Hypervisor filesystem for Linux on s390. Diag 204 and 224
4 * implementation.
5 *
6 * Copyright IBM Corp. 2006, 2008
7 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
8 */
9
10#define KMSG_COMPONENT "hypfs"
11#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
12
13#include <linux/types.h>
14#include <linux/errno.h>
15#include <linux/slab.h>
16#include <linux/string.h>
17#include <linux/vmalloc.h>
18#include <linux/mm.h>
19#include <asm/diag.h>
20#include <asm/ebcdic.h>
21#include "hypfs_diag.h"
22#include "hypfs.h"
23
24#define DBFS_D204_HDR_VERSION 0
25
26static enum diag204_sc diag204_store_sc; /* used subcode for store */
27static enum diag204_format diag204_info_type; /* used diag 204 data format */
28
29static void *diag204_buf; /* 4K aligned buffer for diag204 data */
30static int diag204_buf_pages; /* number of pages for diag204 data */
31
32static struct dentry *dbfs_d204_file;
33
34enum diag204_format diag204_get_info_type(void)
35{
36 return diag204_info_type;
37}
38
39static void diag204_set_info_type(enum diag204_format type)
40{
41 diag204_info_type = type;
42}
43
44/* Diagnose 204 functions */
45/*
46 * For the old diag subcode 4 with simple data format we have to use real
47 * memory. If we use subcode 6 or 7 with extended data format, we can (and
48 * should) use vmalloc, since we need a lot of memory in that case. Currently
49 * up to 93 pages!
50 */
51
52static void diag204_free_buffer(void)
53{
54 vfree(addr: diag204_buf);
55 diag204_buf = NULL;
56}
57
58void *diag204_get_buffer(enum diag204_format fmt, int *pages)
59{
60 if (diag204_buf) {
61 *pages = diag204_buf_pages;
62 return diag204_buf;
63 }
64 if (fmt == DIAG204_INFO_SIMPLE) {
65 *pages = 1;
66 } else {/* DIAG204_INFO_EXT */
67 *pages = diag204((unsigned long)DIAG204_SUBC_RSI |
68 (unsigned long)DIAG204_INFO_EXT, 0, NULL);
69 if (*pages <= 0)
70 return ERR_PTR(error: -EOPNOTSUPP);
71 }
72 diag204_buf = __vmalloc_node(array_size(*pages, PAGE_SIZE),
73 PAGE_SIZE, GFP_KERNEL, NUMA_NO_NODE,
74 caller: __builtin_return_address(0));
75 if (!diag204_buf)
76 return ERR_PTR(error: -ENOMEM);
77 diag204_buf_pages = *pages;
78 return diag204_buf;
79}
80
81/*
82 * diag204_probe() has to find out, which type of diagnose 204 implementation
83 * we have on our machine. Currently there are three possible scanarios:
84 * - subcode 4 + simple data format (only one page)
85 * - subcode 4-6 + extended data format
86 * - subcode 4-7 + extended data format
87 *
88 * Subcode 5 is used to retrieve the size of the data, provided by subcodes
89 * 6 and 7. Subcode 7 basically has the same function as subcode 6. In addition
90 * to subcode 6 it provides also information about secondary cpus.
91 * In order to get as much information as possible, we first try
92 * subcode 7, then 6 and if both fail, we use subcode 4.
93 */
94
95static int diag204_probe(void)
96{
97 void *buf;
98 int pages, rc;
99
100 buf = diag204_get_buffer(fmt: DIAG204_INFO_EXT, pages: &pages);
101 if (!IS_ERR(ptr: buf)) {
102 if (diag204((unsigned long)DIAG204_SUBC_STIB7 |
103 (unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
104 diag204_store_sc = DIAG204_SUBC_STIB7;
105 diag204_set_info_type(type: DIAG204_INFO_EXT);
106 goto out;
107 }
108 if (diag204((unsigned long)DIAG204_SUBC_STIB6 |
109 (unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
110 diag204_store_sc = DIAG204_SUBC_STIB6;
111 diag204_set_info_type(type: DIAG204_INFO_EXT);
112 goto out;
113 }
114 diag204_free_buffer();
115 }
116
117 /* subcodes 6 and 7 failed, now try subcode 4 */
118
119 buf = diag204_get_buffer(fmt: DIAG204_INFO_SIMPLE, pages: &pages);
120 if (IS_ERR(ptr: buf)) {
121 rc = PTR_ERR(ptr: buf);
122 goto fail_alloc;
123 }
124 if (diag204((unsigned long)DIAG204_SUBC_STIB4 |
125 (unsigned long)DIAG204_INFO_SIMPLE, pages, buf) >= 0) {
126 diag204_store_sc = DIAG204_SUBC_STIB4;
127 diag204_set_info_type(type: DIAG204_INFO_SIMPLE);
128 goto out;
129 } else {
130 rc = -EOPNOTSUPP;
131 goto fail_store;
132 }
133out:
134 rc = 0;
135fail_store:
136 diag204_free_buffer();
137fail_alloc:
138 return rc;
139}
140
141int diag204_store(void *buf, int pages)
142{
143 int rc;
144
145 rc = diag204((unsigned long)diag204_store_sc |
146 (unsigned long)diag204_get_info_type(), pages, buf);
147 return rc < 0 ? -EOPNOTSUPP : 0;
148}
149
150struct dbfs_d204_hdr {
151 u64 len; /* Length of d204 buffer without header */
152 u16 version; /* Version of header */
153 u8 sc; /* Used subcode */
154 char reserved[53];
155} __attribute__ ((packed));
156
157struct dbfs_d204 {
158 struct dbfs_d204_hdr hdr; /* 64 byte header */
159 char buf[]; /* d204 buffer */
160} __attribute__ ((packed));
161
162static int dbfs_d204_create(void **data, void **data_free_ptr, size_t *size)
163{
164 struct dbfs_d204 *d204;
165 int rc, buf_size;
166 void *base;
167
168 buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
169 base = vzalloc(size: buf_size);
170 if (!base)
171 return -ENOMEM;
172 d204 = PTR_ALIGN(base + sizeof(d204->hdr), PAGE_SIZE) - sizeof(d204->hdr);
173 rc = diag204_store(buf: d204->buf, pages: diag204_buf_pages);
174 if (rc) {
175 vfree(addr: base);
176 return rc;
177 }
178 d204->hdr.version = DBFS_D204_HDR_VERSION;
179 d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
180 d204->hdr.sc = diag204_store_sc;
181 *data = d204;
182 *data_free_ptr = base;
183 *size = d204->hdr.len + sizeof(struct dbfs_d204_hdr);
184 return 0;
185}
186
187static struct hypfs_dbfs_file dbfs_file_d204 = {
188 .name = "diag_204",
189 .data_create = dbfs_d204_create,
190 .data_free = vfree,
191};
192
193__init int hypfs_diag_init(void)
194{
195 int rc;
196
197 if (diag204_probe()) {
198 pr_info("The hardware system does not support hypfs\n");
199 return -ENODATA;
200 }
201
202 if (diag204_get_info_type() == DIAG204_INFO_EXT)
203 hypfs_dbfs_create_file(df: &dbfs_file_d204);
204
205 rc = hypfs_diag_fs_init();
206 if (rc) {
207 pr_err("The hardware system does not provide all functions required by hypfs\n");
208 debugfs_remove(dentry: dbfs_d204_file);
209 }
210 return rc;
211}
212
213void hypfs_diag_exit(void)
214{
215 debugfs_remove(dentry: dbfs_d204_file);
216 hypfs_diag_fs_exit();
217 diag204_free_buffer();
218 hypfs_dbfs_remove_file(df: &dbfs_file_d204);
219}
220

source code of linux/arch/s390/hypfs/hypfs_diag.c