xref: /openbmc/linux/arch/s390/hypfs/hypfs_vm.c (revision 3325b4d8)
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 
diag2fc(int size,char * query,void * addr)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) : "0" (&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  */
diag2fc_store(char * query,unsigned int * count,int offset)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 
diag2fc_free(const void * data)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 
dbfs_diag2fc_create(void ** data,void ** data_free_ptr,size_t * size)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 
hypfs_vm_init(void)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 
hypfs_vm_exit(void)136 void hypfs_vm_exit(void)
137 {
138 	if (!MACHINE_IS_VM)
139 		return;
140 	hypfs_dbfs_remove_file(&dbfs_file_2fc);
141 }
142