1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Hypervisor filesystem for Linux on s390. z/VM implementation.
4 *
5 * Copyright IBM Corp. 2006
6 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
7 */
8
9 #include <linux/types.h>
10 #include <linux/errno.h>
11 #include <linux/string.h>
12 #include <linux/vmalloc.h>
13 #include <asm/extable.h>
14 #include <asm/diag.h>
15 #include <asm/ebcdic.h>
16 #include <asm/timex.h>
17 #include "hypfs_vm.h"
18 #include "hypfs.h"
19
20 #define DBFS_D2FC_HDR_VERSION 0
21
22 static char local_guest[] = " ";
23 static char all_guests[] = "* ";
24 static char *all_groups = all_guests;
25 char *diag2fc_guest_query;
26
27 static int diag2fc(int size, char* query, void *addr)
28 {
29 unsigned long residual_cnt;
30 unsigned long rc;
31 struct diag2fc_parm_list parm_list;
32
33 memcpy(parm_list.userid, query, DIAG2FC_NAME_LEN);
34 ASCEBC(parm_list.userid, DIAG2FC_NAME_LEN);
35 memcpy(parm_list.aci_grp, all_groups, DIAG2FC_NAME_LEN);
36 ASCEBC(parm_list.aci_grp, DIAG2FC_NAME_LEN);
37 parm_list.addr = (unsigned long)addr;
38 parm_list.size = size;
39 parm_list.fmt = 0x02;
40 rc = -1;
41
42 diag_stat_inc(DIAG_STAT_X2FC);
43 asm volatile(
44 " diag %0,%1,0x2fc\n"
45 "0: nopr %%r7\n"
46 EX_TABLE(0b,0b)
47 : "=d" (residual_cnt), "+d" (rc) : "" (&parm_list) : "memory");
48
49 if ((rc != 0 ) && (rc != -2))
50 return rc;
51 else
52 return -residual_cnt;
53 }
54
55 /*
56 * Allocate buffer for "query" and store diag 2fc at "offset"
57 */
58 void *diag2fc_store(char *query, unsigned int *count, int offset)
59 {
60 void *data;
61 int size;
62
63 do {
64 size = diag2fc(0, query, NULL);
65 if (size < 0)
66 return ERR_PTR(-EACCES);
67 data = vmalloc(size + offset);
68 if (!data)
69 return ERR_PTR(-ENOMEM);
70 if (diag2fc(size, query, data + offset) == 0)
71 break;
72 vfree(data);
73 } while (1);
74 *count = (size / sizeof(struct diag2fc_data));
75
76 return data;
77 }
78
79 void diag2fc_free(const void *data)
80 {
81 vfree(data);
82 }
83
84 struct dbfs_d2fc_hdr {
85 u64 len; /* Length of d2fc buffer without header */
86 u16 version; /* Version of header */
87 union tod_clock tod_ext; /* TOD clock for d2fc */
88 u64 count; /* Number of VM guests in d2fc buffer */
89 char reserved[30];
90 } __attribute__ ((packed));
91
92 struct dbfs_d2fc {
93 struct dbfs_d2fc_hdr hdr; /* 64 byte header */
94 char buf[]; /* d2fc buffer */
95 } __attribute__ ((packed));
96
97 static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size)
98 {
99 struct dbfs_d2fc *d2fc;
100 unsigned int count;
101
102 d2fc = diag2fc_store(diag2fc_guest_query, &count, sizeof(d2fc->hdr));
103 if (IS_ERR(d2fc))
104 return PTR_ERR(d2fc);
105 store_tod_clock_ext(&d2fc->hdr.tod_ext);
106 d2fc->hdr.len = count * sizeof(struct diag2fc_data);
107 d2fc->hdr.version = DBFS_D2FC_HDR_VERSION;
108 d2fc->hdr.count = count;
109 memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved));
110 *data = d2fc;
111 *data_free_ptr = d2fc;
112 *size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr);
113 return 0;
114 }
115
116 static struct hypfs_dbfs_file dbfs_file_2fc = {
117 .name = "diag_2fc",
118 .data_create = dbfs_diag2fc_create,
119 .data_free = diag2fc_free,
120 };
121
122 int hypfs_vm_init(void)
123 {
124 if (!MACHINE_IS_VM)
125 return 0;
126 if (diag2fc(0, all_guests, NULL) > 0)
127 diag2fc_guest_query = all_guests;
128 else if (diag2fc(0, local_guest, NULL) > 0)
129 diag2fc_guest_query = local_guest;
130 else
131 return -EACCES;
132 hypfs_dbfs_create_file(&dbfs_file_2fc);
133 return 0;
134 }
135
136 void hypfs_vm_exit(void)
137 {
138 if (!MACHINE_IS_VM)
139 return;
140 hypfs_dbfs_remove_file(&dbfs_file_2fc);
141 }
142
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