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/machine.h>
15 #include <asm/diag.h>
16 #include <asm/ebcdic.h>
17 #include <asm/timex.h>
18 #include "hypfs_vm.h"
19 #include "hypfs.h"
20
21 #define DBFS_D2FC_HDR_VERSION 0
22
23 static char local_guest[] = " ";
24 static char all_guests[] = "* ";
25 static char *all_groups = all_guests;
26 char *diag2fc_guest_query;
27
diag2fc(int size,char * query,void * addr)28 static int diag2fc(int size, char* query, void *addr)
29 {
30 unsigned long residual_cnt;
31 unsigned long rc;
32 struct diag2fc_parm_list parm_list;
33
34 memcpy(parm_list.userid, query, DIAG2FC_NAME_LEN);
35 ASCEBC(parm_list.userid, DIAG2FC_NAME_LEN);
36 memcpy(parm_list.aci_grp, all_groups, DIAG2FC_NAME_LEN);
37 ASCEBC(parm_list.aci_grp, DIAG2FC_NAME_LEN);
38 parm_list.addr = (unsigned long)addr;
39 parm_list.size = size;
40 parm_list.fmt = 0x02;
41 rc = -1;
42
43 diag_stat_inc(DIAG_STAT_X2FC);
44 asm volatile(
45 " diag %0,%1,0x2fc\n"
46 "0: nopr %%r7\n"
47 EX_TABLE(0b,0b)
48 : "=d" (residual_cnt), "+d" (rc) : "0" (&parm_list) : "memory");
49
50 if ((rc != 0 ) && (rc != -2))
51 return rc;
52 else
53 return -residual_cnt;
54 }
55
56 /*
57 * Allocate buffer for "query" and store diag 2fc at "offset"
58 */
diag2fc_store(char * query,unsigned int * count,int offset)59 void *diag2fc_store(char *query, unsigned int *count, int offset)
60 {
61 void *data;
62 int size;
63
64 do {
65 size = diag2fc(0, query, NULL);
66 if (size < 0)
67 return ERR_PTR(-EACCES);
68 data = vmalloc(size + offset);
69 if (!data)
70 return ERR_PTR(-ENOMEM);
71 if (diag2fc(size, query, data + offset) == 0)
72 break;
73 vfree(data);
74 } while (1);
75 *count = (size / sizeof(struct diag2fc_data));
76
77 return data;
78 }
79
diag2fc_free(const void * data)80 void diag2fc_free(const void *data)
81 {
82 vfree(data);
83 }
84
85 struct dbfs_d2fc_hdr {
86 u64 len; /* Length of d2fc buffer without header */
87 u16 version; /* Version of header */
88 union tod_clock tod_ext; /* TOD clock for d2fc */
89 u64 count; /* Number of VM guests in d2fc buffer */
90 char reserved[30];
91 } __attribute__ ((packed));
92
93 struct dbfs_d2fc {
94 struct dbfs_d2fc_hdr hdr; /* 64 byte header */
95 char buf[]; /* d2fc buffer */
96 } __attribute__ ((packed));
97
dbfs_diag2fc_create(void ** data,void ** data_free_ptr,size_t * size)98 static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size)
99 {
100 struct dbfs_d2fc *d2fc;
101 unsigned int count;
102
103 d2fc = diag2fc_store(diag2fc_guest_query, &count, sizeof(d2fc->hdr));
104 if (IS_ERR(d2fc))
105 return PTR_ERR(d2fc);
106 store_tod_clock_ext(&d2fc->hdr.tod_ext);
107 d2fc->hdr.len = count * sizeof(struct diag2fc_data);
108 d2fc->hdr.version = DBFS_D2FC_HDR_VERSION;
109 d2fc->hdr.count = count;
110 memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved));
111 *data = d2fc;
112 *data_free_ptr = d2fc;
113 *size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr);
114 return 0;
115 }
116
117 static struct hypfs_dbfs_file dbfs_file_2fc = {
118 .name = "diag_2fc",
119 .data_create = dbfs_diag2fc_create,
120 .data_free = diag2fc_free,
121 };
122
hypfs_vm_init(void)123 int hypfs_vm_init(void)
124 {
125 if (!machine_is_vm())
126 return 0;
127 if (diag2fc(0, all_guests, NULL) > 0)
128 diag2fc_guest_query = all_guests;
129 else if (diag2fc(0, local_guest, NULL) > 0)
130 diag2fc_guest_query = local_guest;
131 else
132 return -EACCES;
133 hypfs_dbfs_create_file(&dbfs_file_2fc);
134 return 0;
135 }
136
hypfs_vm_exit(void)137 void hypfs_vm_exit(void)
138 {
139 if (!machine_is_vm())
140 return;
141 hypfs_dbfs_remove_file(&dbfs_file_2fc);
142 }
143