arch/sparc/kernel/hvapi.c

   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_NIAG_PERF,    .flags = FLAG_PRE_API   },
  45         { .group = HV_GRP_FIRE_PERF,                            },
  46         { .group = HV_GRP_N2_CPU,                               },
  47         { .group = HV_GRP_NIU,                                  },
  48         { .group = HV_GRP_VF_CPU,                               },
  49         { .group = HV_GRP_KT_CPU,                               },
  50         { .group = HV_GRP_VT_CPU,                               },
  51         { .group = HV_GRP_T5_CPU,                               },
  52         { .group = HV_GRP_DIAG,         .flags = FLAG_PRE_API   },
  53         { .group = HV_GRP_M7_PERF,                              },
  54 };
  55
  56 static DEFINE_SPINLOCK(hvapi_lock);
  57
  58 static struct api_info *__get_info(unsigned long group)
  59 {
  60         int i;
  61
  62         for (i = 0; i < ARRAY_SIZE(api_table); i++) {
  63                 if (api_table[i].group == group)
  64                         return &api_table[i];
  65         }
  66         return NULL;
  67 }
  68
  69 static void __get_ref(struct api_info *p)
  70 {
  71         p->refcnt++;
  72 }
  73
  74 static void __put_ref(struct api_info *p)
  75 {
  76         if (--p->refcnt == 0) {
  77                 unsigned long ignore;
  78
  79                 sun4v_set_version(p->group, 0, 0, &ignore);
  80                 p->major = p->minor = 0;
  81         }
  82 }
  83
  84 /* Register a hypervisor API specification.  It indicates the
  85  * API group and desired major+minor.
  86  *
  87  * If an existing API registration exists '0' (success) will
  88  * be returned if it is compatible with the one being registered.
  89  * Otherwise a negative error code will be returned.
  90  *
  91  * Otherwise an attempt will be made to negotiate the requested
  92  * API group/major/minor with the hypervisor, and errors returned
  93  * if that does not succeed.
  94  */
  95 int sun4v_hvapi_register(unsigned long group, unsigned long major,
  96                          unsigned long *minor)
  97 {
  98         struct api_info *p;
  99         unsigned long flags;
 100         int ret;
 101
 102         spin_lock_irqsave(&hvapi_lock, flags);
 103         p = __get_info(group);
 104         ret = -EINVAL;
 105         if (p) {
 106                 if (p->refcnt) {
 107                         ret = -EINVAL;
 108                         if (p->major == major) {
 109                                 *minor = p->minor;
 110                                 ret = 0;
 111                         }
 112                 } else {
 113                         unsigned long actual_minor;
 114                         unsigned long hv_ret;
 115
 116                         hv_ret = sun4v_set_version(group, major, *minor,
 117                                                    &actual_minor);
 118                         ret = -EINVAL;
 119                         if (hv_ret == HV_EOK) {
 120                                 *minor = actual_minor;
 121                                 p->major = major;
 122                                 p->minor = actual_minor;
 123                                 ret = 0;
 124                         } else if (hv_ret == HV_EBADTRAP ||
 125                                    hv_ret == HV_ENOTSUPPORTED) {
 126                                 if (p->flags & FLAG_PRE_API) {
 127                                         if (major == 1) {
 128                                                 p->major = 1;
 129                                                 p->minor = 0;
 130                                                 *minor = 0;
 131                                                 ret = 0;
 132                                         }
 133                                 }
 134                         }
 135                 }
 136
 137                 if (ret == 0)
 138                         __get_ref(p);
 139         }
 140         spin_unlock_irqrestore(&hvapi_lock, flags);
 141
 142         return ret;
 143 }
 144 EXPORT_SYMBOL(sun4v_hvapi_register);
 145
 146 void sun4v_hvapi_unregister(unsigned long group)
 147 {
 148         struct api_info *p;
 149         unsigned long flags;
 150
 151         spin_lock_irqsave(&hvapi_lock, flags);
 152         p = __get_info(group);
 153         if (p)
 154                 __put_ref(p);
 155         spin_unlock_irqrestore(&hvapi_lock, flags);
 156 }
 157 EXPORT_SYMBOL(sun4v_hvapi_unregister);
 158
 159 int sun4v_hvapi_get(unsigned long group,
 160                     unsigned long *major,
 161                     unsigned long *minor)
 162 {
 163         struct api_info *p;
 164         unsigned long flags;
 165         int ret;
 166
 167         spin_lock_irqsave(&hvapi_lock, flags);
 168         ret = -EINVAL;
 169         p = __get_info(group);
 170         if (p && p->refcnt) {
 171                 *major = p->major;
 172                 *minor = p->minor;
 173                 ret = 0;
 174         }
 175         spin_unlock_irqrestore(&hvapi_lock, flags);
 176
 177         return ret;
 178 }
 179 EXPORT_SYMBOL(sun4v_hvapi_get);
 180
 181 void __init sun4v_hvapi_init(void)
 182 {
 183         unsigned long group, major, minor;
 184
 185         group = HV_GRP_SUN4V;
 186         major = 1;
 187         minor = 0;
 188         if (sun4v_hvapi_register(group, major, &minor))
 189                 goto bad;
 190
 191         group = HV_GRP_CORE;
 192         major = 1;
 193         minor = 6;
 194         if (sun4v_hvapi_register(group, major, &minor))
 195                 goto bad;
 196
 197         return;
 198
 199 bad:
 200         prom_printf("HVAPI: Cannot register API group "
 201                     "%lx with major(%lu) minor(%lu)\n",
 202                     group, major, minor);
 203         prom_halt();
 204 }