xref: /linux/arch/s390/hypfs/hypfs_diag.c (revision 3a39d672e7f48b8d6b91a09afa4b55352773b4b5)
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