1 /* 2 * Copyright (c) 2016-2025, Arm Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #include <assert.h> 8 #include <stdbool.h> 9 #include <string.h> 10 11 #include <platform_def.h> 12 13 #include <arch.h> 14 #include <arch_features.h> 15 #include <arch_helpers.h> 16 #include <common/bl_common.h> 17 #include <context.h> 18 #include <lib/el3_runtime/context_mgmt.h> 19 #include <lib/extensions/amu.h> 20 #include <lib/extensions/pmuv3.h> 21 #include <lib/extensions/sys_reg_trace.h> 22 #include <lib/extensions/trf.h> 23 #include <lib/utils.h> 24 25 /******************************************************************************* 26 * Context management library initialisation routine. This library is used by 27 * runtime services to share pointers to 'cpu_context' structures for the secure 28 * and non-secure states. Management of the structures and their associated 29 * memory is not done by the context management library e.g. the PSCI service 30 * manages the cpu context used for entry from and exit to the non-secure state. 31 * The Secure payload manages the context(s) corresponding to the secure state. 32 * It also uses this library to get access to the non-secure 33 * state cpu context pointers. 34 ******************************************************************************/ 35 void cm_init(void) 36 { 37 /* 38 * The context management library has only global data to initialize, but 39 * that will be done when the BSS is zeroed out 40 */ 41 } 42 43 /******************************************************************************* 44 * The following function initializes the cpu_context 'ctx' for 45 * first use, and sets the initial entrypoint state as specified by the 46 * entry_point_info structure. 47 * 48 * The security state to initialize is determined by the SECURE attribute 49 * of the entry_point_info. 50 * 51 * The EE and ST attributes are used to configure the endianness and secure 52 * timer availability for the new execution context. 53 * 54 * To prepare the register state for entry call cm_prepare_el3_exit() and 55 * el3_exit(). For Secure-EL1 cm_prepare_el3_exit() is equivalent to 56 * cm_el1_sysregs_context_restore(). 57 ******************************************************************************/ 58 void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep) 59 { 60 unsigned int security_state; 61 uint32_t scr, sctlr; 62 regs_t *reg_ctx; 63 64 assert(ctx != NULL); 65 66 security_state = GET_SECURITY_STATE(ep->h.attr); 67 68 /* Clear any residual register values from the context */ 69 zeromem(ctx, sizeof(*ctx)); 70 71 reg_ctx = get_regs_ctx(ctx); 72 73 /* 74 * Base the context SCR on the current value, adjust for entry point 75 * specific requirements 76 */ 77 scr = read_scr(); 78 scr &= ~(SCR_NS_BIT | SCR_HCE_BIT); 79 80 if (security_state != SECURE) 81 scr |= SCR_NS_BIT; 82 83 if (security_state != SECURE) { 84 /* 85 * Set up SCTLR for the Non-secure context. 86 * 87 * SCTLR.EE: Endianness is taken from the entrypoint attributes. 88 * 89 * SCTLR.M, SCTLR.C and SCTLR.I: These fields must be zero (as 90 * required by PSCI specification) 91 * 92 * Set remaining SCTLR fields to their architecturally defined 93 * values. Some fields reset to an IMPLEMENTATION DEFINED value: 94 * 95 * SCTLR.TE: Set to zero so that exceptions to an Exception 96 * Level executing at PL1 are taken to A32 state. 97 * 98 * SCTLR.V: Set to zero to select the normal exception vectors 99 * with base address held in VBAR. 100 */ 101 assert(((ep->spsr >> SPSR_E_SHIFT) & SPSR_E_MASK) == 102 (EP_GET_EE(ep->h.attr) >> EP_EE_SHIFT)); 103 104 sctlr = (EP_GET_EE(ep->h.attr) != 0U) ? SCTLR_EE_BIT : 0U; 105 sctlr |= (SCTLR_RESET_VAL & ~(SCTLR_TE_BIT | SCTLR_V_BIT)); 106 write_ctx_reg(reg_ctx, CTX_NS_SCTLR, sctlr); 107 } 108 109 /* 110 * The target exception level is based on the spsr mode requested. If 111 * execution is requested to hyp mode, HVC is enabled via SCR.HCE. 112 */ 113 if (GET_M32(ep->spsr) == MODE32_hyp) 114 scr |= SCR_HCE_BIT; 115 116 /* 117 * Store the initialised values for SCTLR and SCR in the cpu_context. 118 * The Hyp mode registers are not part of the saved context and are 119 * set-up in cm_prepare_el3_exit(). 120 */ 121 write_ctx_reg(reg_ctx, CTX_SCR, scr); 122 write_ctx_reg(reg_ctx, CTX_LR, ep->pc); 123 write_ctx_reg(reg_ctx, CTX_SPSR, ep->spsr); 124 125 /* 126 * Store the r0-r3 value from the entrypoint into the context 127 * Use memcpy as we are in control of the layout of the structures 128 */ 129 memcpy((void *)reg_ctx, (void *)&ep->args, sizeof(aapcs32_params_t)); 130 } 131 132 /******************************************************************************* 133 * Enable architecture extensions on first entry to Non-secure world. 134 * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise 135 * it is zero. 136 ******************************************************************************/ 137 static void enable_extensions_nonsecure(bool el2_unused) 138 { 139 #if IMAGE_BL32 140 if (is_feat_amu_supported()) { 141 amu_enable(el2_unused); 142 } 143 144 if (is_feat_sys_reg_trace_supported()) { 145 sys_reg_trace_init_el3(); 146 } 147 148 if (is_feat_trf_supported()) { 149 trf_init_el3(); 150 } 151 152 if (is_feat_pmuv3_present()) { 153 pmuv3_init_el3(); 154 } 155 #endif /* IMAGE_BL32 */ 156 } 157 158 /******************************************************************************* 159 * The following function initializes the cpu_context for the current CPU 160 * for first use, and sets the initial entrypoint state as specified by the 161 * entry_point_info structure. 162 ******************************************************************************/ 163 void cm_init_my_context(const entry_point_info_t *ep) 164 { 165 cpu_context_t *ctx; 166 ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr)); 167 cm_setup_context(ctx, ep); 168 } 169 170 /******************************************************************************* 171 * Prepare the CPU system registers for first entry into secure or normal world 172 * 173 * If execution is requested to hyp mode, HSCTLR is initialized 174 * If execution is requested to non-secure PL1, and the CPU supports 175 * HYP mode then HYP mode is disabled by configuring all necessary HYP mode 176 * registers. 177 ******************************************************************************/ 178 void cm_prepare_el3_exit(size_t security_state) 179 { 180 uint32_t hsctlr, scr; 181 cpu_context_t *ctx = cm_get_context(security_state); 182 bool el2_unused = false; 183 184 assert(ctx != NULL); 185 186 if (security_state == NON_SECURE) { 187 scr = read_ctx_reg(get_regs_ctx(ctx), CTX_SCR); 188 if ((scr & SCR_HCE_BIT) != 0U) { 189 /* Use SCTLR value to initialize HSCTLR */ 190 hsctlr = read_ctx_reg(get_regs_ctx(ctx), 191 CTX_NS_SCTLR); 192 hsctlr |= HSCTLR_RES1; 193 /* Temporarily set the NS bit to access HSCTLR */ 194 write_scr(read_scr() | SCR_NS_BIT); 195 /* 196 * Make sure the write to SCR is complete so that 197 * we can access HSCTLR 198 */ 199 isb(); 200 write_hsctlr(hsctlr); 201 isb(); 202 203 write_scr(read_scr() & ~SCR_NS_BIT); 204 isb(); 205 } else if ((read_id_pfr1() & 206 (ID_PFR1_VIRTEXT_MASK << ID_PFR1_VIRTEXT_SHIFT)) != 0U) { 207 el2_unused = true; 208 209 /* 210 * Set the NS bit to access NS copies of certain banked 211 * registers 212 */ 213 write_scr(read_scr() | SCR_NS_BIT); 214 isb(); 215 216 /* 217 * Hyp / PL2 present but unused, need to disable safely. 218 * HSCTLR can be ignored in this case. 219 * 220 * Set HCR to its architectural reset value so that 221 * Non-secure operations do not trap to Hyp mode. 222 */ 223 write_hcr(HCR_RESET_VAL); 224 225 /* 226 * Set HCPTR to its architectural reset value so that 227 * Non-secure access from EL1 or EL0 to trace and to 228 * Advanced SIMD and floating point functionality does 229 * not trap to Hyp mode. 230 */ 231 write_hcptr(HCPTR_RESET_VAL); 232 233 /* 234 * Initialise CNTHCTL. All fields are architecturally 235 * UNKNOWN on reset and are set to zero except for 236 * field(s) listed below. 237 * 238 * CNTHCTL.PL1PCEN: Disable traps to Hyp mode of 239 * Non-secure EL0 and EL1 accessed to the physical 240 * timer registers. 241 * 242 * CNTHCTL.PL1PCTEN: Disable traps to Hyp mode of 243 * Non-secure EL0 and EL1 accessed to the physical 244 * counter registers. 245 */ 246 write_cnthctl(CNTHCTL_RESET_VAL | 247 PL1PCEN_BIT | PL1PCTEN_BIT); 248 249 /* 250 * Initialise CNTVOFF to zero as it resets to an 251 * IMPLEMENTATION DEFINED value. 252 */ 253 write64_cntvoff(0); 254 255 /* 256 * Set VPIDR and VMPIDR to match MIDR_EL1 and MPIDR 257 * respectively. 258 */ 259 write_vpidr(read_midr()); 260 write_vmpidr(read_mpidr()); 261 262 /* 263 * Initialise VTTBR, setting all fields rather than 264 * relying on the hw. Some fields are architecturally 265 * UNKNOWN at reset. 266 * 267 * VTTBR.VMID: Set to zero which is the architecturally 268 * defined reset value. Even though EL1&0 stage 2 269 * address translation is disabled, cache maintenance 270 * operations depend on the VMID. 271 * 272 * VTTBR.BADDR: Set to zero as EL1&0 stage 2 address 273 * translation is disabled. 274 */ 275 write64_vttbr(VTTBR_RESET_VAL & 276 ~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT) 277 | (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT))); 278 279 /* 280 * Initialise HDCR, setting all the fields rather than 281 * relying on hw. 282 * 283 * HDCR.HPMN: Set to value of PMCR.N which is the 284 * architecturally-defined reset value. 285 * 286 * HDCR.HLP: Set to one so that event counter 287 * overflow, that is recorded in PMOVSCLR[0-30], 288 * occurs on the increment that changes 289 * PMEVCNTR<n>[63] from 1 to 0, when ARMv8.5-PMU is 290 * implemented. This bit is RES0 in versions of the 291 * architecture earlier than ARMv8.5, setting it to 1 292 * doesn't have any effect on them. 293 * This bit is Reserved, UNK/SBZP in ARMv7. 294 * 295 * HDCR.HPME: Set to zero to disable EL2 Event 296 * counters. 297 */ 298 #if (ARM_ARCH_MAJOR > 7) 299 write_hdcr((HDCR_RESET_VAL | HDCR_HLP_BIT | 300 ((read_pmcr() & PMCR_N_BITS) >> 301 PMCR_N_SHIFT)) & ~HDCR_HPME_BIT); 302 #else 303 write_hdcr((HDCR_RESET_VAL | 304 ((read_pmcr() & PMCR_N_BITS) >> 305 PMCR_N_SHIFT)) & ~HDCR_HPME_BIT); 306 #endif 307 /* 308 * Set HSTR to its architectural reset value so that 309 * access to system registers in the cproc=1111 310 * encoding space do not trap to Hyp mode. 311 */ 312 write_hstr(HSTR_RESET_VAL); 313 /* 314 * Set CNTHP_CTL to its architectural reset value to 315 * disable the EL2 physical timer and prevent timer 316 * interrupts. Some fields are architecturally UNKNOWN 317 * on reset and are set to zero. 318 */ 319 write_cnthp_ctl(CNTHP_CTL_RESET_VAL); 320 isb(); 321 322 write_scr(read_scr() & ~SCR_NS_BIT); 323 isb(); 324 } 325 enable_extensions_nonsecure(el2_unused); 326 } 327 } 328 329 /******************************************************************************* 330 * This function is used to exit to Non-secure world. It simply calls the 331 * cm_prepare_el3_exit function for AArch32. 332 ******************************************************************************/ 333 void cm_prepare_el3_exit_ns(void) 334 { 335 cm_prepare_el3_exit(NON_SECURE); 336 } 337