1 // SPDX-License-Identifier: GPL-2.0
2 /* hvapi.c: Hypervisor API management.
3 *
4 * Copyright (C) 2007 David S. Miller <davem@davemloft.net>
5 */
6 #include <linux/kernel.h>
7 #include <linux/export.h>
8 #include <linux/init.h>
9
10 #include <asm/hypervisor.h>
11 #include <asm/oplib.h>
12
13 /* If the hypervisor indicates that the API setting
14 * calls are unsupported, by returning HV_EBADTRAP or
15 * HV_ENOTSUPPORTED, we assume that API groups with the
16 * PRE_API flag set are major 1 minor 0.
17 */
18 struct api_info {
19 unsigned long group;
20 unsigned long major;
21 unsigned long minor;
22 unsigned int refcnt;
23 unsigned int flags;
24 #define FLAG_PRE_API 0x00000001
25 };
26
27 static struct api_info api_table[] = {
28 { .group = HV_GRP_SUN4V, .flags = FLAG_PRE_API },
29 { .group = HV_GRP_CORE, .flags = FLAG_PRE_API },
30 { .group = HV_GRP_INTR, },
31 { .group = HV_GRP_SOFT_STATE, },
32 { .group = HV_GRP_TM, },
33 { .group = HV_GRP_PCI, .flags = FLAG_PRE_API },
34 { .group = HV_GRP_LDOM, },
35 { .group = HV_GRP_SVC_CHAN, .flags = FLAG_PRE_API },
36 { .group = HV_GRP_NCS, .flags = FLAG_PRE_API },
37 { .group = HV_GRP_RNG, },
38 { .group = HV_GRP_PBOOT, },
39 { .group = HV_GRP_TPM, },
40 { .group = HV_GRP_SDIO, },
41 { .group = HV_GRP_SDIO_ERR, },
42 { .group = HV_GRP_REBOOT_DATA, },
43 { .group = HV_GRP_ATU, .flags = FLAG_PRE_API },
44 { .group = HV_GRP_DAX, },
45 { .group = HV_GRP_NIAG_PERF, .flags = FLAG_PRE_API },
46 { .group = HV_GRP_FIRE_PERF, },
47 { .group = HV_GRP_N2_CPU, },
48 { .group = HV_GRP_NIU, },
49 { .group = HV_GRP_VF_CPU, },
50 { .group = HV_GRP_KT_CPU, },
51 { .group = HV_GRP_VT_CPU, },
52 { .group = HV_GRP_T5_CPU, },
53 { .group = HV_GRP_DIAG, .flags = FLAG_PRE_API },
54 { .group = HV_GRP_M7_PERF, },
55 };
56
57 static DEFINE_SPINLOCK(hvapi_lock);
58
__get_info(unsigned long group)59 static struct api_info *__get_info(unsigned long group)
60 {
61 int i;
62
63 for (i = 0; i < ARRAY_SIZE(api_table); i++) {
64 if (api_table[i].group == group)
65 return &api_table[i];
66 }
67 return NULL;
68 }
69
__get_ref(struct api_info * p)70 static void __get_ref(struct api_info *p)
71 {
72 p->refcnt++;
73 }
74
__put_ref(struct api_info * p)75 static void __put_ref(struct api_info *p)
76 {
77 if (--p->refcnt == 0) {
78 unsigned long ignore;
79
80 sun4v_set_version(p->group, 0, 0, &ignore);
81 p->major = p->minor = 0;
82 }
83 }
84
85 /* Register a hypervisor API specification. It indicates the
86 * API group and desired major+minor.
87 *
88 * If an existing API registration exists '0' (success) will
89 * be returned if it is compatible with the one being registered.
90 * Otherwise a negative error code will be returned.
91 *
92 * Otherwise an attempt will be made to negotiate the requested
93 * API group/major/minor with the hypervisor, and errors returned
94 * if that does not succeed.
95 */
sun4v_hvapi_register(unsigned long group,unsigned long major,unsigned long * minor)96 int sun4v_hvapi_register(unsigned long group, unsigned long major,
97 unsigned long *minor)
98 {
99 struct api_info *p;
100 unsigned long flags;
101 int ret;
102
103 spin_lock_irqsave(&hvapi_lock, flags);
104 p = __get_info(group);
105 ret = -EINVAL;
106 if (p) {
107 if (p->refcnt) {
108 ret = -EINVAL;
109 if (p->major == major) {
110 *minor = p->minor;
111 ret = 0;
112 }
113 } else {
114 unsigned long actual_minor;
115 unsigned long hv_ret;
116
117 hv_ret = sun4v_set_version(group, major, *minor,
118 &actual_minor);
119 ret = -EINVAL;
120 if (hv_ret == HV_EOK) {
121 *minor = actual_minor;
122 p->major = major;
123 p->minor = actual_minor;
124 ret = 0;
125 } else if (hv_ret == HV_EBADTRAP ||
126 hv_ret == HV_ENOTSUPPORTED) {
127 if (p->flags & FLAG_PRE_API) {
128 if (major == 1) {
129 p->major = 1;
130 p->minor = 0;
131 *minor = 0;
132 ret = 0;
133 }
134 }
135 }
136 }
137
138 if (ret == 0)
139 __get_ref(p);
140 }
141 spin_unlock_irqrestore(&hvapi_lock, flags);
142
143 return ret;
144 }
145 EXPORT_SYMBOL(sun4v_hvapi_register);
146
sun4v_hvapi_unregister(unsigned long group)147 void sun4v_hvapi_unregister(unsigned long group)
148 {
149 struct api_info *p;
150 unsigned long flags;
151
152 spin_lock_irqsave(&hvapi_lock, flags);
153 p = __get_info(group);
154 if (p)
155 __put_ref(p);
156 spin_unlock_irqrestore(&hvapi_lock, flags);
157 }
158 EXPORT_SYMBOL(sun4v_hvapi_unregister);
159
sun4v_hvapi_get(unsigned long group,unsigned long * major,unsigned long * minor)160 int sun4v_hvapi_get(unsigned long group,
161 unsigned long *major,
162 unsigned long *minor)
163 {
164 struct api_info *p;
165 unsigned long flags;
166 int ret;
167
168 spin_lock_irqsave(&hvapi_lock, flags);
169 ret = -EINVAL;
170 p = __get_info(group);
171 if (p && p->refcnt) {
172 *major = p->major;
173 *minor = p->minor;
174 ret = 0;
175 }
176 spin_unlock_irqrestore(&hvapi_lock, flags);
177
178 return ret;
179 }
180 EXPORT_SYMBOL(sun4v_hvapi_get);
181
sun4v_hvapi_init(void)182 void __init sun4v_hvapi_init(void)
183 {
184 unsigned long group, major, minor;
185
186 group = HV_GRP_SUN4V;
187 major = 1;
188 minor = 0;
189 if (sun4v_hvapi_register(group, major, &minor))
190 goto bad;
191
192 group = HV_GRP_CORE;
193 major = 1;
194 minor = 6;
195 if (sun4v_hvapi_register(group, major, &minor))
196 goto bad;
197
198 return;
199
200 bad:
201 prom_printf("HVAPI: Cannot register API group "
202 "%lx with major(%lu) minor(%lu)\n",
203 group, major, minor);
204 prom_halt();
205 }
206