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
26 static enum diag204_sc diag204_store_sc; /* used subcode for store */
27 static enum diag204_format diag204_info_type; /* used diag 204 data format */
28
29 static void *diag204_buf; /* 4K aligned buffer for diag204 data */
30 static int diag204_buf_pages; /* number of pages for diag204 data */
31
32 static struct dentry *dbfs_d204_file;
33
34 enum diag204_format diag204_get_info_type(void)
35 {
36 return diag204_info_type;
37 }
38
39 static 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
52 static void diag204_free_buffer(void)
53 {
54 vfree(diag204_buf);
55 diag204_buf = NULL;
56 }
57
58 void *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(-EOPNOTSUPP);
71 }
72 diag204_buf = __vmalloc_node(array_size(*pages, PAGE_SIZE),
73 PAGE_SIZE, GFP_KERNEL, NUMA_NO_NODE,
74 __builtin_return_address(0));
75 if (!diag204_buf)
76 return ERR_PTR(-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
95 static int diag204_probe(void)
96 {
97 void *buf;
98 int pages, rc;
99
100 buf = diag204_get_buffer(DIAG204_INFO_EXT, &pages);
101 if (!IS_ERR(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(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(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(DIAG204_INFO_SIMPLE, &pages);
120 if (IS_ERR(buf)) {
121 rc = PTR_ERR(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(DIAG204_INFO_SIMPLE);
128 goto out;
129 } else {
130 rc = -EOPNOTSUPP;
131 goto fail_store;
132 }
133 out:
134 rc = 0;
135 fail_store:
136 diag204_free_buffer();
137 fail_alloc:
138 return rc;
139 }
140
141 int diag204_store(void *buf, int pages)
142 {
143 unsigned long subcode;
144 int rc;
145
146 subcode = diag204_get_info_type();
147 subcode |= diag204_store_sc;
148 if (diag204_has_bif())
149 subcode |= DIAG204_BIF_BIT;
150 while (1) {
151 rc = diag204(subcode, pages, buf);
152 if (rc != -EBUSY)
153 break;
154 if (signal_pending(current))
155 return -ERESTARTSYS;
156 schedule_timeout_interruptible(DIAG204_BUSY_WAIT);
157 }
158 return rc < 0 ? rc : 0;
159 }
160
161 struct dbfs_d204_hdr {
162 u64 len; /* Length of d204 buffer without header */
163 u16 version; /* Version of header */
164 u8 sc; /* Used subcode */
165 char reserved[53];
166 } __attribute__ ((packed));
167
168 struct dbfs_d204 {
169 struct dbfs_d204_hdr hdr; /* 64 byte header */
170 char buf[]; /* d204 buffer */
171 } __attribute__ ((packed));
172
173 static int dbfs_d204_create(void **data, void **data_free_ptr, size_t *size)
174 {
175 struct dbfs_d204 *d204;
176 int rc, buf_size;
177 void *base;
178
179 buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
180 base = vzalloc(buf_size);
181 if (!base)
182 return -ENOMEM;
183 d204 = PTR_ALIGN(base + sizeof(d204->hdr), PAGE_SIZE) - sizeof(d204->hdr);
184 rc = diag204_store(d204->buf, diag204_buf_pages);
185 if (rc) {
186 vfree(base);
187 return rc;
188 }
189 d204->hdr.version = DBFS_D204_HDR_VERSION;
190 d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
191 d204->hdr.sc = diag204_store_sc;
192 *data = d204;
193 *data_free_ptr = base;
194 *size = d204->hdr.len + sizeof(struct dbfs_d204_hdr);
195 return 0;
196 }
197
198 static struct hypfs_dbfs_file dbfs_file_d204 = {
199 .name = "diag_204",
200 .data_create = dbfs_d204_create,
201 .data_free = vfree,
202 };
203
204 __init int hypfs_diag_init(void)
205 {
206 int rc;
207
208 if (diag204_probe()) {
209 pr_info("The hardware system does not support hypfs\n");
210 return -ENODATA;
211 }
212
213 if (diag204_get_info_type() == DIAG204_INFO_EXT)
214 hypfs_dbfs_create_file(&dbfs_file_d204);
215
216 rc = hypfs_diag_fs_init();
217 if (rc) {
218 pr_err("The hardware system does not provide all functions required by hypfs\n");
219 debugfs_remove(dbfs_d204_file);
220 }
221 return rc;
222 }
223
224 void hypfs_diag_exit(void)
225 {
226 debugfs_remove(dbfs_d204_file);
227 hypfs_diag_fs_exit();
228 diag204_free_buffer();
229 hypfs_dbfs_remove_file(&dbfs_file_d204);
230 }
231
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