Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 1 | /* |
| 2 | * runtime-wrappers.c - Runtime Services function call wrappers |
| 3 | * |
| 4 | * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org> |
| 5 | * |
| 6 | * Split off from arch/x86/platform/efi/efi.c |
| 7 | * |
| 8 | * Copyright (C) 1999 VA Linux Systems |
| 9 | * Copyright (C) 1999 Walt Drummond <drummond@valinux.com> |
| 10 | * Copyright (C) 1999-2002 Hewlett-Packard Co. |
| 11 | * Copyright (C) 2005-2008 Intel Co. |
| 12 | * Copyright (C) 2013 SuSE Labs |
| 13 | * |
| 14 | * This file is released under the GPLv2. |
| 15 | */ |
| 16 | |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 17 | #include <linux/bug.h> |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 18 | #include <linux/efi.h> |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 19 | #include <linux/mutex.h> |
| 20 | #include <linux/spinlock.h> |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 21 | #include <asm/efi.h> |
| 22 | |
| 23 | /* |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 24 | * According to section 7.1 of the UEFI spec, Runtime Services are not fully |
| 25 | * reentrant, and there are particular combinations of calls that need to be |
| 26 | * serialized. (source: UEFI Specification v2.4A) |
| 27 | * |
| 28 | * Table 31. Rules for Reentry Into Runtime Services |
| 29 | * +------------------------------------+-------------------------------+ |
| 30 | * | If previous call is busy in | Forbidden to call | |
| 31 | * +------------------------------------+-------------------------------+ |
| 32 | * | Any | SetVirtualAddressMap() | |
| 33 | * +------------------------------------+-------------------------------+ |
| 34 | * | ConvertPointer() | ConvertPointer() | |
| 35 | * +------------------------------------+-------------------------------+ |
| 36 | * | SetVariable() | ResetSystem() | |
| 37 | * | UpdateCapsule() | | |
| 38 | * | SetTime() | | |
| 39 | * | SetWakeupTime() | | |
| 40 | * | GetNextHighMonotonicCount() | | |
| 41 | * +------------------------------------+-------------------------------+ |
| 42 | * | GetVariable() | GetVariable() | |
| 43 | * | GetNextVariableName() | GetNextVariableName() | |
| 44 | * | SetVariable() | SetVariable() | |
| 45 | * | QueryVariableInfo() | QueryVariableInfo() | |
| 46 | * | UpdateCapsule() | UpdateCapsule() | |
| 47 | * | QueryCapsuleCapabilities() | QueryCapsuleCapabilities() | |
| 48 | * | GetNextHighMonotonicCount() | GetNextHighMonotonicCount() | |
| 49 | * +------------------------------------+-------------------------------+ |
| 50 | * | GetTime() | GetTime() | |
| 51 | * | SetTime() | SetTime() | |
| 52 | * | GetWakeupTime() | GetWakeupTime() | |
| 53 | * | SetWakeupTime() | SetWakeupTime() | |
| 54 | * +------------------------------------+-------------------------------+ |
| 55 | * |
| 56 | * Due to the fact that the EFI pstore may write to the variable store in |
| 57 | * interrupt context, we need to use a spinlock for at least the groups that |
| 58 | * contain SetVariable() and QueryVariableInfo(). That leaves little else, as |
| 59 | * none of the remaining functions are actually ever called at runtime. |
| 60 | * So let's just use a single spinlock to serialize all Runtime Services calls. |
| 61 | */ |
| 62 | static DEFINE_SPINLOCK(efi_runtime_lock); |
| 63 | |
| 64 | /* |
| 65 | * Some runtime services calls can be reentrant under NMI, even if the table |
| 66 | * above says they are not. (source: UEFI Specification v2.4A) |
| 67 | * |
| 68 | * Table 32. Functions that may be called after Machine Check, INIT and NMI |
| 69 | * +----------------------------+------------------------------------------+ |
| 70 | * | Function | Called after Machine Check, INIT and NMI | |
| 71 | * +----------------------------+------------------------------------------+ |
| 72 | * | GetTime() | Yes, even if previously busy. | |
| 73 | * | GetVariable() | Yes, even if previously busy | |
| 74 | * | GetNextVariableName() | Yes, even if previously busy | |
| 75 | * | QueryVariableInfo() | Yes, even if previously busy | |
| 76 | * | SetVariable() | Yes, even if previously busy | |
| 77 | * | UpdateCapsule() | Yes, even if previously busy | |
| 78 | * | QueryCapsuleCapabilities() | Yes, even if previously busy | |
| 79 | * | ResetSystem() | Yes, even if previously busy | |
| 80 | * +----------------------------+------------------------------------------+ |
| 81 | * |
| 82 | * In order to prevent deadlocks under NMI, the wrappers for these functions |
| 83 | * may only grab the efi_runtime_lock or rtc_lock spinlocks if !efi_in_nmi(). |
| 84 | * However, not all of the services listed are reachable through NMI code paths, |
| 85 | * so the the special handling as suggested by the UEFI spec is only implemented |
| 86 | * for QueryVariableInfo() and SetVariable(), as these can be reached in NMI |
| 87 | * context through efi_pstore_write(). |
| 88 | */ |
| 89 | #ifndef efi_in_nmi |
| 90 | #define efi_in_nmi() (0) |
| 91 | #endif |
| 92 | |
| 93 | /* |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 94 | * As per commit ef68c8f87ed1 ("x86: Serialize EFI time accesses on rtc_lock"), |
| 95 | * the EFI specification requires that callers of the time related runtime |
| 96 | * functions serialize with other CMOS accesses in the kernel, as the EFI time |
| 97 | * functions may choose to also use the legacy CMOS RTC. |
| 98 | */ |
| 99 | __weak DEFINE_SPINLOCK(rtc_lock); |
| 100 | |
| 101 | static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) |
| 102 | { |
| 103 | unsigned long flags; |
| 104 | efi_status_t status; |
| 105 | |
| 106 | spin_lock_irqsave(&rtc_lock, flags); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 107 | spin_lock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 108 | status = efi_call_virt(get_time, tm, tc); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 109 | spin_unlock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 110 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 111 | return status; |
| 112 | } |
| 113 | |
| 114 | static efi_status_t virt_efi_set_time(efi_time_t *tm) |
| 115 | { |
| 116 | unsigned long flags; |
| 117 | efi_status_t status; |
| 118 | |
| 119 | spin_lock_irqsave(&rtc_lock, flags); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 120 | spin_lock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 121 | status = efi_call_virt(set_time, tm); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 122 | spin_unlock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 123 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 124 | return status; |
| 125 | } |
| 126 | |
| 127 | static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, |
| 128 | efi_bool_t *pending, |
| 129 | efi_time_t *tm) |
| 130 | { |
| 131 | unsigned long flags; |
| 132 | efi_status_t status; |
| 133 | |
| 134 | spin_lock_irqsave(&rtc_lock, flags); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 135 | spin_lock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 136 | status = efi_call_virt(get_wakeup_time, enabled, pending, tm); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 137 | spin_unlock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 138 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 139 | return status; |
| 140 | } |
| 141 | |
| 142 | static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) |
| 143 | { |
| 144 | unsigned long flags; |
| 145 | efi_status_t status; |
| 146 | |
| 147 | spin_lock_irqsave(&rtc_lock, flags); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 148 | spin_lock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 149 | status = efi_call_virt(set_wakeup_time, enabled, tm); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 150 | spin_unlock(&efi_runtime_lock); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 151 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 152 | return status; |
| 153 | } |
| 154 | |
| 155 | static efi_status_t virt_efi_get_variable(efi_char16_t *name, |
| 156 | efi_guid_t *vendor, |
| 157 | u32 *attr, |
| 158 | unsigned long *data_size, |
| 159 | void *data) |
| 160 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 161 | unsigned long flags; |
| 162 | efi_status_t status; |
| 163 | |
| 164 | spin_lock_irqsave(&efi_runtime_lock, flags); |
| 165 | status = efi_call_virt(get_variable, name, vendor, attr, data_size, |
| 166 | data); |
| 167 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
| 168 | return status; |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 169 | } |
| 170 | |
| 171 | static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, |
| 172 | efi_char16_t *name, |
| 173 | efi_guid_t *vendor) |
| 174 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 175 | unsigned long flags; |
| 176 | efi_status_t status; |
| 177 | |
| 178 | spin_lock_irqsave(&efi_runtime_lock, flags); |
| 179 | status = efi_call_virt(get_next_variable, name_size, name, vendor); |
| 180 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
| 181 | return status; |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 182 | } |
| 183 | |
| 184 | static efi_status_t virt_efi_set_variable(efi_char16_t *name, |
| 185 | efi_guid_t *vendor, |
| 186 | u32 attr, |
| 187 | unsigned long data_size, |
| 188 | void *data) |
| 189 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 190 | unsigned long flags; |
| 191 | efi_status_t status; |
| 192 | bool __in_nmi = efi_in_nmi(); |
| 193 | |
| 194 | if (!__in_nmi) |
| 195 | spin_lock_irqsave(&efi_runtime_lock, flags); |
| 196 | status = efi_call_virt(set_variable, name, vendor, attr, data_size, |
| 197 | data); |
| 198 | if (!__in_nmi) |
| 199 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
| 200 | return status; |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 201 | } |
| 202 | |
| 203 | static efi_status_t virt_efi_query_variable_info(u32 attr, |
| 204 | u64 *storage_space, |
| 205 | u64 *remaining_space, |
| 206 | u64 *max_variable_size) |
| 207 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 208 | unsigned long flags; |
| 209 | efi_status_t status; |
| 210 | bool __in_nmi = efi_in_nmi(); |
| 211 | |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 212 | if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) |
| 213 | return EFI_UNSUPPORTED; |
| 214 | |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 215 | if (!__in_nmi) |
| 216 | spin_lock_irqsave(&efi_runtime_lock, flags); |
| 217 | status = efi_call_virt(query_variable_info, attr, storage_space, |
| 218 | remaining_space, max_variable_size); |
| 219 | if (!__in_nmi) |
| 220 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
| 221 | return status; |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 222 | } |
| 223 | |
| 224 | static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) |
| 225 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 226 | unsigned long flags; |
| 227 | efi_status_t status; |
| 228 | |
| 229 | spin_lock_irqsave(&efi_runtime_lock, flags); |
| 230 | status = efi_call_virt(get_next_high_mono_count, count); |
| 231 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
| 232 | return status; |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 233 | } |
| 234 | |
| 235 | static void virt_efi_reset_system(int reset_type, |
| 236 | efi_status_t status, |
| 237 | unsigned long data_size, |
| 238 | efi_char16_t *data) |
| 239 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 240 | unsigned long flags; |
| 241 | |
| 242 | spin_lock_irqsave(&efi_runtime_lock, flags); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 243 | __efi_call_virt(reset_system, reset_type, status, data_size, data); |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 244 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 245 | } |
| 246 | |
| 247 | static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, |
| 248 | unsigned long count, |
| 249 | unsigned long sg_list) |
| 250 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 251 | unsigned long flags; |
| 252 | efi_status_t status; |
| 253 | |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 254 | if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) |
| 255 | return EFI_UNSUPPORTED; |
| 256 | |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 257 | spin_lock_irqsave(&efi_runtime_lock, flags); |
| 258 | status = efi_call_virt(update_capsule, capsules, count, sg_list); |
| 259 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
| 260 | return status; |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 261 | } |
| 262 | |
| 263 | static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, |
| 264 | unsigned long count, |
| 265 | u64 *max_size, |
| 266 | int *reset_type) |
| 267 | { |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 268 | unsigned long flags; |
| 269 | efi_status_t status; |
| 270 | |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 271 | if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) |
| 272 | return EFI_UNSUPPORTED; |
| 273 | |
Ard Biesheuvel | 161485e | 2014-08-04 18:16:00 +0200 | [diff] [blame] | 274 | spin_lock_irqsave(&efi_runtime_lock, flags); |
| 275 | status = efi_call_virt(query_capsule_caps, capsules, count, max_size, |
| 276 | reset_type); |
| 277 | spin_unlock_irqrestore(&efi_runtime_lock, flags); |
| 278 | return status; |
Ard Biesheuvel | 022ee6c | 2014-06-26 12:09:05 +0200 | [diff] [blame] | 279 | } |
| 280 | |
| 281 | void efi_native_runtime_setup(void) |
| 282 | { |
| 283 | efi.get_time = virt_efi_get_time; |
| 284 | efi.set_time = virt_efi_set_time; |
| 285 | efi.get_wakeup_time = virt_efi_get_wakeup_time; |
| 286 | efi.set_wakeup_time = virt_efi_set_wakeup_time; |
| 287 | efi.get_variable = virt_efi_get_variable; |
| 288 | efi.get_next_variable = virt_efi_get_next_variable; |
| 289 | efi.set_variable = virt_efi_set_variable; |
| 290 | efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; |
| 291 | efi.reset_system = virt_efi_reset_system; |
| 292 | efi.query_variable_info = virt_efi_query_variable_info; |
| 293 | efi.update_capsule = virt_efi_update_capsule; |
| 294 | efi.query_capsule_caps = virt_efi_query_capsule_caps; |
| 295 | } |