1 /* 2 * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #ifndef CONTEXT_H 8 #define CONTEXT_H 9 10 #if (CTX_INCLUDE_EL2_REGS && IMAGE_BL31) 11 #include <lib/el3_runtime/context_el2.h> 12 #else 13 /** 14 * El1 context is required either when: 15 * IMAGE_BL1 || ((!CTX_INCLUDE_EL2_REGS) && IMAGE_BL31) 16 */ 17 #include <lib/el3_runtime/context_el1.h> 18 #endif /* (CTX_INCLUDE_EL2_REGS && IMAGE_BL31) */ 19 20 #include <lib/el3_runtime/simd_ctx.h> 21 #include <lib/utils_def.h> 22 #include <platform_def.h> /* For CACHE_WRITEBACK_GRANULE */ 23 24 #define CPU_CONTEXT_SECURE UL(0) 25 #define CPU_CONTEXT_NS UL(1) 26 #if ENABLE_RME 27 #define CPU_CONTEXT_REALM UL(2) 28 #define CPU_CONTEXT_NUM UL(3) 29 #else 30 #define CPU_CONTEXT_NUM UL(2) 31 #endif 32 33 /******************************************************************************* 34 * Constants that allow assembler code to access members of and the 'gp_regs' 35 * structure at their correct offsets. 36 ******************************************************************************/ 37 #define CTX_GPREGS_OFFSET U(0x0) 38 #define CTX_GPREG_X0 U(0x0) 39 #define CTX_GPREG_X1 U(0x8) 40 #define CTX_GPREG_X2 U(0x10) 41 #define CTX_GPREG_X3 U(0x18) 42 #define CTX_GPREG_X4 U(0x20) 43 #define CTX_GPREG_X5 U(0x28) 44 #define CTX_GPREG_X6 U(0x30) 45 #define CTX_GPREG_X7 U(0x38) 46 #define CTX_GPREG_X8 U(0x40) 47 #define CTX_GPREG_X9 U(0x48) 48 #define CTX_GPREG_X10 U(0x50) 49 #define CTX_GPREG_X11 U(0x58) 50 #define CTX_GPREG_X12 U(0x60) 51 #define CTX_GPREG_X13 U(0x68) 52 #define CTX_GPREG_X14 U(0x70) 53 #define CTX_GPREG_X15 U(0x78) 54 #define CTX_GPREG_X16 U(0x80) 55 #define CTX_GPREG_X17 U(0x88) 56 #define CTX_GPREG_X18 U(0x90) 57 #define CTX_GPREG_X19 U(0x98) 58 #define CTX_GPREG_X20 U(0xa0) 59 #define CTX_GPREG_X21 U(0xa8) 60 #define CTX_GPREG_X22 U(0xb0) 61 #define CTX_GPREG_X23 U(0xb8) 62 #define CTX_GPREG_X24 U(0xc0) 63 #define CTX_GPREG_X25 U(0xc8) 64 #define CTX_GPREG_X26 U(0xd0) 65 #define CTX_GPREG_X27 U(0xd8) 66 #define CTX_GPREG_X28 U(0xe0) 67 #define CTX_GPREG_X29 U(0xe8) 68 #define CTX_GPREG_LR U(0xf0) 69 #define CTX_GPREG_SP_EL0 U(0xf8) 70 #define CTX_GPREGS_END U(0x100) 71 72 /******************************************************************************* 73 * Constants that allow assembler code to access members of and the 'el3_state' 74 * structure at their correct offsets. Note that some of the registers are only 75 * 32-bits wide but are stored as 64-bit values for convenience 76 ******************************************************************************/ 77 #define CTX_EL3STATE_OFFSET (CTX_GPREGS_OFFSET + CTX_GPREGS_END) 78 #define CTX_SCR_EL3 U(0x0) 79 #define CTX_RUNTIME_SP U(0x8) 80 #define CTX_SPSR_EL3 U(0x10) 81 #define CTX_ELR_EL3 U(0x18) 82 #define CTX_PMCR_EL0 U(0x20) 83 #define CTX_IS_IN_EL3 U(0x28) 84 #define CTX_MDCR_EL3 U(0x30) 85 /* Constants required in supporting nested exception in EL3 */ 86 #define CTX_SAVED_ELR_EL3 U(0x38) 87 /* 88 * General purpose flag, to save various EL3 states 89 * FFH mode : Used to identify if handling nested exception 90 * KFH mode : Used as counter value 91 */ 92 #define CTX_NESTED_EA_FLAG U(0x40) 93 #if FFH_SUPPORT 94 #define CTX_SAVED_ESR_EL3 U(0x48) 95 #define CTX_SAVED_SPSR_EL3 U(0x50) 96 #define CTX_SAVED_GPREG_LR U(0x58) 97 #define CTX_DOUBLE_FAULT_ESR U(0x60) 98 #define CTX_EL3STATE_END U(0x70) /* Align to the next 16 byte boundary */ 99 #else 100 #define CTX_EL3STATE_END U(0x50) /* Align to the next 16 byte boundary */ 101 #endif /* FFH_SUPPORT */ 102 103 104 /******************************************************************************* 105 * Registers related to CVE-2018-3639 106 ******************************************************************************/ 107 #define CTX_CVE_2018_3639_OFFSET (CTX_EL3STATE_OFFSET + CTX_EL3STATE_END) 108 #define CTX_CVE_2018_3639_DISABLE U(0) 109 #define CTX_CVE_2018_3639_END U(0x10) /* Align to the next 16 byte boundary */ 110 111 /******************************************************************************* 112 * Registers related to ERRATA_SPECULATIVE_AT 113 * 114 * This is essential as with EL1 and EL2 context registers being decoupled, 115 * both will not be present for a given build configuration. 116 * As ERRATA_SPECULATIVE_AT errata requires SCTLR_EL1 and TCR_EL1 registers 117 * independent of the above logic, we need explicit context entries to be 118 * reserved for these registers. 119 * 120 * NOTE: Based on this we end up with following different configurations depending 121 * on the presence of errata and inclusion of EL1 or EL2 context. 122 * 123 * ============================================================================ 124 * | ERRATA_SPECULATIVE_AT | EL1 context| Memory allocation(Sctlr_el1,Tcr_el1)| 125 * ============================================================================ 126 * | 0 | 0 | None | 127 * | 0 | 1 | EL1 C-Context structure | 128 * | 1 | 0 | Errata Context Offset Entries | 129 * | 1 | 1 | Errata Context Offset Entries | 130 * ============================================================================ 131 * 132 * In the above table, when ERRATA_SPECULATIVE_AT=1, EL1_Context=0, it implies 133 * there is only EL2 context and memory for SCTLR_EL1 and TCR_EL1 registers is 134 * reserved explicitly under ERRATA_SPECULATIVE_AT build flag here. 135 * 136 * In situations when EL1_Context=1 and ERRATA_SPECULATIVE_AT=1, since SCTLR_EL1 137 * and TCR_EL1 registers will be modified under errata and it happens at the 138 * early in the codeflow prior to el1 context (save and restore operations), 139 * context memory still will be reserved under the errata logic here explicitly. 140 * These registers will not be part of EL1 context save & restore routines. 141 * 142 * Only when ERRATA_SPECULATIVE_AT=0, EL1_Context=1, for this combination, 143 * SCTLR_EL1 and TCR_EL1 will be part of EL1 context structure (context_el1.h) 144 * ----------------------------------------------------------------------------- 145 ******************************************************************************/ 146 #define CTX_ERRATA_SPEC_AT_OFFSET (CTX_CVE_2018_3639_OFFSET + CTX_CVE_2018_3639_END) 147 #if ERRATA_SPECULATIVE_AT 148 #define CTX_ERRATA_SPEC_AT_SCTLR_EL1 U(0x0) 149 #define CTX_ERRATA_SPEC_AT_TCR_EL1 U(0x8) 150 #define CTX_ERRATA_SPEC_AT_END U(0x10) /* Align to the next 16 byte boundary */ 151 #else 152 #define CTX_ERRATA_SPEC_AT_END U(0x0) 153 #endif /* ERRATA_SPECULATIVE_AT */ 154 155 /******************************************************************************* 156 * Registers related to ARMv8.3-PAuth. 157 ******************************************************************************/ 158 #define CTX_PAUTH_REGS_OFFSET (CTX_ERRATA_SPEC_AT_OFFSET + CTX_ERRATA_SPEC_AT_END) 159 #if CTX_INCLUDE_PAUTH_REGS 160 #define CTX_PACIAKEY_LO U(0x0) 161 #define CTX_PACIAKEY_HI U(0x8) 162 #define CTX_PACIBKEY_LO U(0x10) 163 #define CTX_PACIBKEY_HI U(0x18) 164 #define CTX_PACDAKEY_LO U(0x20) 165 #define CTX_PACDAKEY_HI U(0x28) 166 #define CTX_PACDBKEY_LO U(0x30) 167 #define CTX_PACDBKEY_HI U(0x38) 168 #define CTX_PACGAKEY_LO U(0x40) 169 #define CTX_PACGAKEY_HI U(0x48) 170 #define CTX_PAUTH_REGS_END U(0x50) /* Align to the next 16 byte boundary */ 171 #else 172 #define CTX_PAUTH_REGS_END U(0) 173 #endif /* CTX_INCLUDE_PAUTH_REGS */ 174 175 /******************************************************************************* 176 * Registers initialised in a per-world context. 177 ******************************************************************************/ 178 #define CTX_CPTR_EL3 U(0x0) 179 #define CTX_MPAM3_EL3 U(0x8) 180 #if (ENABLE_FEAT_IDTE3 && IMAGE_BL31) 181 #define CTX_IDREGS_EL3 U(0x10) 182 #define CTX_PERWORLD_EL3STATE_END U(0x78) 183 #else 184 #define CTX_PERWORLD_EL3STATE_END U(0x10) 185 #endif /* ENABLE_FEAT_IDTE3 && IMAGE_BL31 */ 186 187 #ifndef __ASSEMBLER__ 188 189 #include <stdint.h> 190 191 #include <assert.h> 192 #include <common/ep_info.h> 193 #include <lib/cassert.h> 194 195 /* 196 * Common constants to help define the 'cpu_context' structure and its 197 * members below. 198 */ 199 #define DWORD_SHIFT U(3) 200 #define DEFINE_REG_STRUCT(name, num_regs) \ 201 typedef struct name { \ 202 uint64_t ctx_regs[num_regs]; \ 203 } __aligned(16) name##_t 204 205 /* Constants to determine the size of individual context structures */ 206 #define CTX_GPREG_ALL (CTX_GPREGS_END >> DWORD_SHIFT) 207 208 #define CTX_EL3STATE_ALL (CTX_EL3STATE_END >> DWORD_SHIFT) 209 #define CTX_CVE_2018_3639_ALL (CTX_CVE_2018_3639_END >> DWORD_SHIFT) 210 211 #if ERRATA_SPECULATIVE_AT 212 #define CTX_ERRATA_SPEC_AT_ALL (CTX_ERRATA_SPEC_AT_END >> DWORD_SHIFT) 213 #endif 214 #if CTX_INCLUDE_PAUTH_REGS 215 # define CTX_PAUTH_REGS_ALL (CTX_PAUTH_REGS_END >> DWORD_SHIFT) 216 #endif 217 218 /* 219 * AArch64 general purpose register context structure. Usually x0-x18, 220 * lr are saved as the compiler is expected to preserve the remaining 221 * callee saved registers if used by the C runtime and the assembler 222 * does not touch the remaining. But in case of world switch during 223 * exception handling, we need to save the callee registers too. 224 */ 225 DEFINE_REG_STRUCT(gp_regs, CTX_GPREG_ALL); 226 227 /* 228 * Miscellaneous registers used by EL3 firmware to maintain its state 229 * across exception entries and exits 230 */ 231 DEFINE_REG_STRUCT(el3_state, CTX_EL3STATE_ALL); 232 233 /* Function pointer used by CVE-2018-3639 dynamic mitigation */ 234 DEFINE_REG_STRUCT(cve_2018_3639, CTX_CVE_2018_3639_ALL); 235 236 /* Registers associated to Errata_Speculative */ 237 #if ERRATA_SPECULATIVE_AT 238 DEFINE_REG_STRUCT(errata_speculative_at, CTX_ERRATA_SPEC_AT_ALL); 239 #endif 240 241 /* Registers associated to ARMv8.3-PAuth */ 242 #if CTX_INCLUDE_PAUTH_REGS 243 DEFINE_REG_STRUCT(pauth, CTX_PAUTH_REGS_ALL); 244 #endif 245 246 /* 247 * Macros to access members of any of the above structures using their 248 * offsets 249 */ 250 #define read_ctx_reg(ctx, offset) ((ctx)->ctx_regs[(offset) >> DWORD_SHIFT]) 251 #define write_ctx_reg(ctx, offset, val) (((ctx)->ctx_regs[(offset) >> DWORD_SHIFT]) \ 252 = (uint64_t) (val)) 253 254 #if ENABLE_FEAT_IDTE3 255 typedef struct perworld_idreg { 256 u_register_t id_aa64pfr0_el1; 257 u_register_t id_aa64pfr1_el1; 258 u_register_t id_aa64pfr2_el1; 259 u_register_t id_aa64smfr0_el1; 260 u_register_t id_aa64isar0_el1; 261 u_register_t id_aa64isar1_el1; 262 u_register_t id_aa64isar2_el1; 263 u_register_t id_aa64isar3_el1; 264 u_register_t id_aa64mmfr0_el1; 265 u_register_t id_aa64mmfr1_el1; 266 u_register_t id_aa64mmfr2_el1; 267 u_register_t id_aa64mmfr3_el1; 268 u_register_t id_aa64mmfr4_el1; 269 } perworld_idregs_t; 270 #endif 271 272 /* 273 * Top-level context structure which is used by EL3 firmware to preserve 274 * the state of a core at the next lower EL in a given security state and 275 * save enough EL3 meta data to be able to return to that EL and security 276 * state. The context management library will be used to ensure that 277 * SP_EL3 always points to an instance of this structure at exception 278 * entry and exit. 279 */ 280 typedef struct cpu_context { 281 gp_regs_t gpregs_ctx; 282 el3_state_t el3state_ctx; 283 284 cve_2018_3639_t cve_2018_3639_ctx; 285 286 #if ERRATA_SPECULATIVE_AT 287 errata_speculative_at_t errata_speculative_at_ctx; 288 #endif 289 290 #if CTX_INCLUDE_PAUTH_REGS 291 pauth_t pauth_ctx; 292 #endif 293 294 #if (CTX_INCLUDE_EL2_REGS && IMAGE_BL31) 295 el2_sysregs_t el2_sysregs_ctx; 296 #else 297 /* El1 context should be included only either for IMAGE_BL1, 298 * or for IMAGE_BL31 when CTX_INCLUDE_EL2_REGS=0: 299 * When SPMD_SPM_AT_SEL2=1, SPMC at S-EL2 takes care of saving 300 * and restoring EL1 registers. In this case, BL31 at EL3 can 301 * exclude save and restore of EL1 context registers. 302 */ 303 el1_sysregs_t el1_sysregs_ctx; 304 #endif 305 306 /* TODO: the CACHE_WRITEBACK_GRANULE alignment is not necessary if this is 307 * contained in a per-cpu data structure (i.e. cpu_data_t). 308 */ 309 } __aligned(CACHE_WRITEBACK_GRANULE) cpu_context_t; 310 311 /* 312 * Per-World Context. 313 * It stores registers whose values can be shared across CPUs. 314 */ 315 typedef struct per_world_context { 316 uint64_t ctx_cptr_el3; 317 uint64_t ctx_mpam3_el3; 318 #if (ENABLE_FEAT_IDTE3 && IMAGE_BL31) 319 perworld_idregs_t idregs; 320 #endif 321 } per_world_context_t; 322 323 static inline uint8_t get_cpu_context_index(size_t security_state) 324 { 325 if (security_state == SECURE) { 326 return CPU_CONTEXT_SECURE; 327 #if ENABLE_RME 328 } else if (security_state == REALM) { 329 return CPU_CONTEXT_REALM; 330 #endif 331 } else { 332 assert(security_state == NON_SECURE); 333 return CPU_CONTEXT_NS; 334 } 335 } 336 337 extern per_world_context_t per_world_context[CPU_CONTEXT_NUM]; 338 339 /* Macros to access members of the 'cpu_context_t' structure */ 340 #define get_el3state_ctx(h) (&((cpu_context_t *) h)->el3state_ctx) 341 342 #if (CTX_INCLUDE_EL2_REGS && IMAGE_BL31) 343 #define get_el2_sysregs_ctx(h) (&((cpu_context_t *) h)->el2_sysregs_ctx) 344 #else 345 #define get_el1_sysregs_ctx(h) (&((cpu_context_t *) h)->el1_sysregs_ctx) 346 #endif 347 348 #define get_gpregs_ctx(h) (&((cpu_context_t *) h)->gpregs_ctx) 349 #define get_cve_2018_3639_ctx(h) (&((cpu_context_t *) h)->cve_2018_3639_ctx) 350 351 #if ERRATA_SPECULATIVE_AT 352 #define get_errata_speculative_at_ctx(h) (&((cpu_context_t *) h)->errata_speculative_at_ctx) 353 #endif 354 355 #if CTX_INCLUDE_PAUTH_REGS 356 # define get_pauth_ctx(h) (&((cpu_context_t *) h)->pauth_ctx) 357 #endif 358 359 /* 360 * Compile time assertions related to the 'cpu_context' structure to 361 * ensure that the assembler and the compiler view of the offsets of 362 * the structure members is the same. 363 */ 364 CASSERT(CTX_GPREGS_OFFSET == __builtin_offsetof(cpu_context_t, gpregs_ctx), 365 assert_core_context_gp_offset_mismatch); 366 367 CASSERT(CTX_EL3STATE_OFFSET == __builtin_offsetof(cpu_context_t, el3state_ctx), 368 assert_core_context_el3state_offset_mismatch); 369 370 371 CASSERT(CTX_CVE_2018_3639_OFFSET == __builtin_offsetof(cpu_context_t, cve_2018_3639_ctx), 372 assert_core_context_cve_2018_3639_offset_mismatch); 373 374 #if ERRATA_SPECULATIVE_AT 375 CASSERT(CTX_ERRATA_SPEC_AT_OFFSET == __builtin_offsetof(cpu_context_t, errata_speculative_at_ctx), 376 assert_core_context_errata_speculative_at_offset_mismatch); 377 #endif 378 379 #if CTX_INCLUDE_PAUTH_REGS 380 CASSERT(CTX_PAUTH_REGS_OFFSET == __builtin_offsetof(cpu_context_t, pauth_ctx), 381 assert_core_context_pauth_offset_mismatch); 382 #endif /* CTX_INCLUDE_PAUTH_REGS */ 383 384 /* 385 * Helper macro to set the general purpose registers that correspond to 386 * parameters in an aapcs_64 call i.e. x0-x7 387 */ 388 #define set_aapcs_args0(ctx, x0) do { \ 389 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X0, x0); \ 390 } while (0) 391 #define set_aapcs_args1(ctx, x0, x1) do { \ 392 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X1, x1); \ 393 set_aapcs_args0(ctx, x0); \ 394 } while (0) 395 #define set_aapcs_args2(ctx, x0, x1, x2) do { \ 396 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X2, x2); \ 397 set_aapcs_args1(ctx, x0, x1); \ 398 } while (0) 399 #define set_aapcs_args3(ctx, x0, x1, x2, x3) do { \ 400 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X3, x3); \ 401 set_aapcs_args2(ctx, x0, x1, x2); \ 402 } while (0) 403 #define set_aapcs_args4(ctx, x0, x1, x2, x3, x4) do { \ 404 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X4, x4); \ 405 set_aapcs_args3(ctx, x0, x1, x2, x3); \ 406 } while (0) 407 #define set_aapcs_args5(ctx, x0, x1, x2, x3, x4, x5) do { \ 408 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X5, x5); \ 409 set_aapcs_args4(ctx, x0, x1, x2, x3, x4); \ 410 } while (0) 411 #define set_aapcs_args6(ctx, x0, x1, x2, x3, x4, x5, x6) do { \ 412 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X6, x6); \ 413 set_aapcs_args5(ctx, x0, x1, x2, x3, x4, x5); \ 414 } while (0) 415 #define set_aapcs_args7(ctx, x0, x1, x2, x3, x4, x5, x6, x7) do { \ 416 write_ctx_reg(get_gpregs_ctx(ctx), CTX_GPREG_X7, x7); \ 417 set_aapcs_args6(ctx, x0, x1, x2, x3, x4, x5, x6); \ 418 } while (0) 419 420 /******************************************************************************* 421 * Function prototypes 422 ******************************************************************************/ 423 #if CTX_INCLUDE_FPREGS 424 void fpregs_context_save(simd_regs_t *regs); 425 void fpregs_context_restore(simd_regs_t *regs); 426 #endif 427 428 /******************************************************************************* 429 * The next four inline functions are required for IMAGE_BL1, as well as for 430 * IMAGE_BL31 for the below combinations. 431 * ============================================================================ 432 * | ERRATA_SPECULATIVE_AT| CTX_INCLUDE_EL2_REGS | Combination | 433 * ============================================================================ 434 * | 0 | 0 | Valid (EL1 ctx) | 435 * |______________________|______________________|____________________________| 436 * | | | Invalid (No Errata/EL1 Ctx)| 437 * | 0 | 1 | Hence commented out. | 438 * |______________________|______________________|____________________________| 439 * | | | | 440 * | 1 | 0 | Valid (Errata ctx) | 441 * |______________________|______________________|____________________________| 442 * | | | | 443 * | 1 | 1 | Valid (Errata ctx) | 444 * |______________________|______________________|____________________________| 445 * ============================================================================ 446 ******************************************************************************/ 447 #if (IMAGE_BL1 || ((ERRATA_SPECULATIVE_AT) || (!CTX_INCLUDE_EL2_REGS))) 448 449 static inline void write_ctx_sctlr_el1_reg_errata(cpu_context_t *ctx, u_register_t val) 450 { 451 #if (ERRATA_SPECULATIVE_AT) 452 write_ctx_reg(get_errata_speculative_at_ctx(ctx), 453 CTX_ERRATA_SPEC_AT_SCTLR_EL1, val); 454 #else 455 write_el1_ctx_common(get_el1_sysregs_ctx(ctx), sctlr_el1, val); 456 #endif /* ERRATA_SPECULATIVE_AT */ 457 } 458 459 static inline void write_ctx_tcr_el1_reg_errata(cpu_context_t *ctx, u_register_t val) 460 { 461 #if (ERRATA_SPECULATIVE_AT) 462 write_ctx_reg(get_errata_speculative_at_ctx(ctx), 463 CTX_ERRATA_SPEC_AT_TCR_EL1, val); 464 #else 465 write_el1_ctx_common(get_el1_sysregs_ctx(ctx), tcr_el1, val); 466 #endif /* ERRATA_SPECULATIVE_AT */ 467 } 468 469 static inline u_register_t read_ctx_sctlr_el1_reg_errata(cpu_context_t *ctx) 470 { 471 #if (ERRATA_SPECULATIVE_AT) 472 return read_ctx_reg(get_errata_speculative_at_ctx(ctx), 473 CTX_ERRATA_SPEC_AT_SCTLR_EL1); 474 #else 475 return read_el1_ctx_common(get_el1_sysregs_ctx(ctx), sctlr_el1); 476 #endif /* ERRATA_SPECULATIVE_AT */ 477 } 478 479 static inline u_register_t read_ctx_tcr_el1_reg_errata(cpu_context_t *ctx) 480 { 481 #if (ERRATA_SPECULATIVE_AT) 482 return read_ctx_reg(get_errata_speculative_at_ctx(ctx), 483 CTX_ERRATA_SPEC_AT_TCR_EL1); 484 #else 485 return read_el1_ctx_common(get_el1_sysregs_ctx(ctx), tcr_el1); 486 #endif /* ERRATA_SPECULATIVE_AT */ 487 } 488 489 #endif /* (IMAGE_BL1 || ((ERRATA_SPECULATIVE_AT) || (!CTX_INCLUDE_EL2_REGS))) */ 490 491 #endif /* __ASSEMBLER__ */ 492 493 #endif /* CONTEXT_H */ 494