target/arm/psci.c

   1 /*
   2  * Copyright (C) 2014 - Linaro
   3  * Author: Rob Herring <rob.herring@linaro.org>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18 #include "qemu/osdep.h"
  19 #include "cpu.h"
  20 #include "exec/helper-proto.h"
  21 #include "kvm-consts.h"
  22 #include "sysemu/sysemu.h"
  23 #include "internals.h"
  24 #include "arm-powerctl.h"
  25 #include "exec/exec-all.h"
  26
  27 bool arm_is_psci_call(ARMCPU *cpu, int excp_type)
  28 {
  29     /* Return true if the r0/x0 value indicates a PSCI call and
  30      * the exception type matches the configured PSCI conduit. This is
  31      * called before the SMC/HVC instruction is executed, to decide whether
  32      * we should treat it as a PSCI call or with the architecturally
  33      * defined behaviour for an SMC or HVC (which might be UNDEF or trap
  34      * to EL2 or to EL3).
  35      */
  36     CPUARMState *env = &cpu->env;
  37     uint64_t param = is_a64(env) ? env->xregs[0] : env->regs[0];
  38
  39     switch (excp_type) {
  40     case EXCP_HVC:
  41         if (cpu->psci_conduit != QEMU_PSCI_CONDUIT_HVC) {
  42             return false;
  43         }
  44         break;
  45     case EXCP_SMC:
  46         if (cpu->psci_conduit != QEMU_PSCI_CONDUIT_SMC) {
  47             return false;
  48         }
  49         break;
  50     default:
  51         return false;
  52     }
  53
  54     switch (param) {
  55     case QEMU_PSCI_0_2_FN_PSCI_VERSION:
  56     case QEMU_PSCI_0_2_FN_MIGRATE_INFO_TYPE:
  57     case QEMU_PSCI_0_2_FN_AFFINITY_INFO:
  58     case QEMU_PSCI_0_2_FN64_AFFINITY_INFO:
  59     case QEMU_PSCI_0_2_FN_SYSTEM_RESET:
  60     case QEMU_PSCI_0_2_FN_SYSTEM_OFF:
  61     case QEMU_PSCI_0_1_FN_CPU_ON:
  62     case QEMU_PSCI_0_2_FN_CPU_ON:
  63     case QEMU_PSCI_0_2_FN64_CPU_ON:
  64     case QEMU_PSCI_0_1_FN_CPU_OFF:
  65     case QEMU_PSCI_0_2_FN_CPU_OFF:
  66     case QEMU_PSCI_0_1_FN_CPU_SUSPEND:
  67     case QEMU_PSCI_0_2_FN_CPU_SUSPEND:
  68     case QEMU_PSCI_0_2_FN64_CPU_SUSPEND:
  69     case QEMU_PSCI_0_1_FN_MIGRATE:
  70     case QEMU_PSCI_0_2_FN_MIGRATE:
  71         return true;
  72     default:
  73         return false;
  74     }
  75 }
  76
  77 void arm_handle_psci_call(ARMCPU *cpu)
  78 {
  79     /*
  80      * This function partially implements the logic for dispatching Power State
  81      * Coordination Interface (PSCI) calls (as described in ARM DEN 0022B.b),
  82      * to the extent required for bringing up and taking down secondary cores,
  83      * and for handling reset and poweroff requests.
  84      * Additional information about the calling convention used is available in
  85      * the document 'SMC Calling Convention' (ARM DEN 0028)
  86      */
  87     CPUARMState *env = &cpu->env;
  88     uint64_t param[4];
  89     uint64_t context_id, mpidr;
  90     target_ulong entry;
  91     int32_t ret = 0;
  92     int i;
  93
  94     for (i = 0; i < 4; i++) {
  95         /*
  96          * All PSCI functions take explicit 32-bit or native int sized
  97          * arguments so we can simply zero-extend all arguments regardless
  98          * of which exact function we are about to call.
  99          */
 100         param[i] = is_a64(env) ? env->xregs[i] : env->regs[i];
 101     }
 102
 103     if ((param[0] & QEMU_PSCI_0_2_64BIT) && !is_a64(env)) {
 104         ret = QEMU_PSCI_RET_INVALID_PARAMS;
 105         goto err;
 106     }
 107
 108     switch (param[0]) {
 109         CPUState *target_cpu_state;
 110         ARMCPU *target_cpu;
 111
 112     case QEMU_PSCI_0_2_FN_PSCI_VERSION:
 113         ret = QEMU_PSCI_0_2_RET_VERSION_0_2;
 114         break;
 115     case QEMU_PSCI_0_2_FN_MIGRATE_INFO_TYPE:
 116         ret = QEMU_PSCI_0_2_RET_TOS_MIGRATION_NOT_REQUIRED; /* No trusted OS */
 117         break;
 118     case QEMU_PSCI_0_2_FN_AFFINITY_INFO:
 119     case QEMU_PSCI_0_2_FN64_AFFINITY_INFO:
 120         mpidr = param[1];
 121
 122         switch (param[2]) {
 123         case 0:
 124             target_cpu_state = arm_get_cpu_by_id(mpidr);
 125             if (!target_cpu_state) {
 126                 ret = QEMU_PSCI_RET_INVALID_PARAMS;
 127                 break;
 128             }
 129             target_cpu = ARM_CPU(target_cpu_state);
 130
 131             g_assert(qemu_mutex_iothread_locked());
 132             ret = target_cpu->power_state;
 133             break;
 134         default:
 135             /* Everything above affinity level 0 is always on. */
 136             ret = 0;
 137         }
 138         break;
 139     case QEMU_PSCI_0_2_FN_SYSTEM_RESET:
 140         qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
 141         /* QEMU reset and shutdown are async requests, but PSCI
 142          * mandates that we never return from the reset/shutdown
 143          * call, so power the CPU off now so it doesn't execute
 144          * anything further.
 145          */
 146         goto cpu_off;
 147     case QEMU_PSCI_0_2_FN_SYSTEM_OFF:
 148         qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
 149         goto cpu_off;
 150     case QEMU_PSCI_0_1_FN_CPU_ON:
 151     case QEMU_PSCI_0_2_FN_CPU_ON:
 152     case QEMU_PSCI_0_2_FN64_CPU_ON:
 153     {
 154         /* The PSCI spec mandates that newly brought up CPUs start
 155          * in the highest exception level which exists and is enabled
 156          * on the calling CPU. Since the QEMU PSCI implementation is
 157          * acting as a "fake EL3" or "fake EL2" firmware, this for us
 158          * means that we want to start at the highest NS exception level
 159          * that we are providing to the guest.
 160          * The execution mode should be that which is currently in use
 161          * by the same exception level on the calling CPU.
 162          * The CPU should be started with the context_id value
 163          * in x0 (if AArch64) or r0 (if AArch32).
 164          */
 165         int target_el = arm_feature(env, ARM_FEATURE_EL2) ? 2 : 1;
 166         bool target_aarch64 = arm_el_is_aa64(env, target_el);
 167
 168         mpidr = param[1];
 169         entry = param[2];
 170         context_id = param[3];
 171         ret = arm_set_cpu_on(mpidr, entry, context_id,
 172                              target_el, target_aarch64);
 173         break;
 174     }
 175     case QEMU_PSCI_0_1_FN_CPU_OFF:
 176     case QEMU_PSCI_0_2_FN_CPU_OFF:
 177         goto cpu_off;
 178     case QEMU_PSCI_0_1_FN_CPU_SUSPEND:
 179     case QEMU_PSCI_0_2_FN_CPU_SUSPEND:
 180     case QEMU_PSCI_0_2_FN64_CPU_SUSPEND:
 181         /* Affinity levels are not supported in QEMU */
 182         if (param[1] & 0xfffe0000) {
 183             ret = QEMU_PSCI_RET_INVALID_PARAMS;
 184             break;
 185         }
 186         /* Powerdown is not supported, we always go into WFI */
 187         if (is_a64(env)) {
 188             env->xregs[0] = 0;
 189         } else {
 190             env->regs[0] = 0;
 191         }
 192         helper_wfi(env);
 193         break;
 194     case QEMU_PSCI_0_1_FN_MIGRATE:
 195     case QEMU_PSCI_0_2_FN_MIGRATE:
 196         ret = QEMU_PSCI_RET_NOT_SUPPORTED;
 197         break;
 198     default:
 199         g_assert_not_reached();
 200     }
 201
 202 err:
 203     if (is_a64(env)) {
 204         env->xregs[0] = ret;
 205     } else {
 206         env->regs[0] = ret;
 207     }
 208     return;
 209
 210 cpu_off:
 211     ret = arm_set_cpu_off(cpu->mp_affinity);
 212     /* notreached */
 213     /* sanity check in case something failed */
 214     assert(ret == QEMU_ARM_POWERCTL_RET_SUCCESS);
 215 }