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
diag204_get_info_type(void)32 enum diag204_format diag204_get_info_type(void)
33 {
34 return diag204_info_type;
35 }
36
diag204_set_info_type(enum diag204_format type)37 static void diag204_set_info_type(enum diag204_format type)
38 {
39 diag204_info_type = type;
40 }
41
42 /* Diagnose 204 functions */
43 /*
44 * For the old diag subcode 4 with simple data format we have to use real
45 * memory. If we use subcode 6 or 7 with extended data format, we can (and
46 * should) use vmalloc, since we need a lot of memory in that case. Currently
47 * up to 93 pages!
48 */
49
diag204_free_buffer(void)50 static void diag204_free_buffer(void)
51 {
52 vfree(diag204_buf);
53 diag204_buf = NULL;
54 }
55
diag204_get_buffer(enum diag204_format fmt,int * pages)56 void *diag204_get_buffer(enum diag204_format fmt, int *pages)
57 {
58 if (diag204_buf) {
59 *pages = diag204_buf_pages;
60 return diag204_buf;
61 }
62 if (fmt == DIAG204_INFO_SIMPLE) {
63 *pages = 1;
64 } else {/* DIAG204_INFO_EXT */
65 *pages = diag204((unsigned long)DIAG204_SUBC_RSI |
66 (unsigned long)DIAG204_INFO_EXT, 0, NULL);
67 if (*pages <= 0)
68 return ERR_PTR(-EOPNOTSUPP);
69 }
70 diag204_buf = __vmalloc_node(array_size(*pages, PAGE_SIZE),
71 PAGE_SIZE, GFP_KERNEL, NUMA_NO_NODE,
72 __builtin_return_address(0));
73 if (!diag204_buf)
74 return ERR_PTR(-ENOMEM);
75 diag204_buf_pages = *pages;
76 return diag204_buf;
77 }
78
79 /*
80 * diag204_probe() has to find out, which type of diagnose 204 implementation
81 * we have on our machine. Currently there are three possible scanarios:
82 * - subcode 4 + simple data format (only one page)
83 * - subcode 4-6 + extended data format
84 * - subcode 4-7 + extended data format
85 *
86 * Subcode 5 is used to retrieve the size of the data, provided by subcodes
87 * 6 and 7. Subcode 7 basically has the same function as subcode 6. In addition
88 * to subcode 6 it provides also information about secondary cpus.
89 * In order to get as much information as possible, we first try
90 * subcode 7, then 6 and if both fail, we use subcode 4.
91 */
92
diag204_probe(void)93 static int diag204_probe(void)
94 {
95 void *buf;
96 int pages, rc;
97
98 buf = diag204_get_buffer(DIAG204_INFO_EXT, &pages);
99 if (!IS_ERR(buf)) {
100 if (diag204((unsigned long)DIAG204_SUBC_STIB7 |
101 (unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
102 diag204_store_sc = DIAG204_SUBC_STIB7;
103 diag204_set_info_type(DIAG204_INFO_EXT);
104 goto out;
105 }
106 if (diag204((unsigned long)DIAG204_SUBC_STIB6 |
107 (unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
108 diag204_store_sc = DIAG204_SUBC_STIB6;
109 diag204_set_info_type(DIAG204_INFO_EXT);
110 goto out;
111 }
112 diag204_free_buffer();
113 }
114
115 /* subcodes 6 and 7 failed, now try subcode 4 */
116
117 buf = diag204_get_buffer(DIAG204_INFO_SIMPLE, &pages);
118 if (IS_ERR(buf)) {
119 rc = PTR_ERR(buf);
120 goto fail_alloc;
121 }
122 if (diag204((unsigned long)DIAG204_SUBC_STIB4 |
123 (unsigned long)DIAG204_INFO_SIMPLE, pages, buf) >= 0) {
124 diag204_store_sc = DIAG204_SUBC_STIB4;
125 diag204_set_info_type(DIAG204_INFO_SIMPLE);
126 goto out;
127 } else {
128 rc = -EOPNOTSUPP;
129 goto fail_store;
130 }
131 out:
132 rc = 0;
133 fail_store:
134 diag204_free_buffer();
135 fail_alloc:
136 return rc;
137 }
138
diag204_store(void * buf,int pages)139 int diag204_store(void *buf, int pages)
140 {
141 unsigned long subcode;
142 int rc;
143
144 subcode = diag204_get_info_type();
145 subcode |= diag204_store_sc;
146 if (diag204_has_bif())
147 subcode |= DIAG204_BIF_BIT;
148 while (1) {
149 rc = diag204(subcode, pages, buf);
150 if (rc != -EBUSY)
151 break;
152 if (signal_pending(current))
153 return -ERESTARTSYS;
154 schedule_timeout_interruptible(DIAG204_BUSY_WAIT);
155 }
156 return rc < 0 ? rc : 0;
157 }
158
159 struct dbfs_d204_hdr {
160 u64 len; /* Length of d204 buffer without header */
161 u16 version; /* Version of header */
162 u8 sc; /* Used subcode */
163 char reserved[53];
164 } __attribute__ ((packed));
165
166 struct dbfs_d204 {
167 struct dbfs_d204_hdr hdr; /* 64 byte header */
168 char buf[]; /* d204 buffer */
169 } __attribute__ ((packed));
170
dbfs_d204_create(void ** data,void ** data_free_ptr,size_t * size)171 static int dbfs_d204_create(void **data, void **data_free_ptr, size_t *size)
172 {
173 struct dbfs_d204 *d204;
174 int rc, buf_size;
175 void *base;
176
177 buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
178 base = vzalloc(buf_size);
179 if (!base)
180 return -ENOMEM;
181 d204 = PTR_ALIGN(base + sizeof(d204->hdr), PAGE_SIZE) - sizeof(d204->hdr);
182 rc = diag204_store(d204->buf, diag204_buf_pages);
183 if (rc) {
184 vfree(base);
185 return rc;
186 }
187 d204->hdr.version = DBFS_D204_HDR_VERSION;
188 d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
189 d204->hdr.sc = diag204_store_sc;
190 *data = d204;
191 *data_free_ptr = base;
192 *size = d204->hdr.len + sizeof(struct dbfs_d204_hdr);
193 return 0;
194 }
195
196 static struct hypfs_dbfs_file dbfs_file_d204 = {
197 .name = "diag_204",
198 .data_create = dbfs_d204_create,
199 .data_free = vfree,
200 };
201
hypfs_diag_init(void)202 __init int hypfs_diag_init(void)
203 {
204 int rc;
205
206 if (diag204_probe()) {
207 pr_info("The hardware system does not support hypfs\n");
208 return -ENODATA;
209 }
210
211 if (diag204_get_info_type() == DIAG204_INFO_EXT)
212 hypfs_dbfs_create_file(&dbfs_file_d204);
213
214 rc = hypfs_diag_fs_init();
215 if (rc)
216 pr_err("The hardware system does not provide all functions required by hypfs\n");
217 return rc;
218 }
219
hypfs_diag_exit(void)220 void hypfs_diag_exit(void)
221 {
222 hypfs_diag_fs_exit();
223 diag204_free_buffer();
224 hypfs_dbfs_remove_file(&dbfs_file_d204);
225 }
226