This reverts commit 9fcd15b919
.
This change turns out to cause regressions, for instance on the
imx6ul boards as described here:
https://lore.kernel.org/qemu-devel/c8b89685-7490-328b-51a3-48711c140a84@tribudubois.net/
The primary cause of that regression is that the guest code running
at EL3 expects SMCs (not related to PSCI) to do what they would if
our PSCI emulation was not present at all, but after this change
they instead set a value in R0/X0 and continue.
We could fix that by a refactoring that allowed us to only turn on
the PSCI emulation if we weren't booting the guest at EL3, but there
is a more tangled problem with the highbank board, which:
(1) wants to enable PSCI emulation
(2) has a bit of guest code that it wants to run at EL3 and
to perform SMC calls that trap to the monitor vector table:
this is the boot stub code that is written to memory by
arm_write_secure_board_setup_dummy_smc() and which the
highbank board enables by setting bootinfo->secure_board_setup
We can't satisfy both of those and also have the PSCI emulation
handle all SMC instruction executions regardless of function
identifier value.
This is too tricky to try to sort out before 6.2 is released;
revert this commit so we can take the time to get it right in
the 7.0 release.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20211119163419.557623-1-peter.maydell@linaro.org
217 lines
7.1 KiB
C
217 lines
7.1 KiB
C
/*
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* Copyright (C) 2014 - Linaro
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* Author: Rob Herring <rob.herring@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "cpu.h"
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#include "exec/helper-proto.h"
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#include "kvm-consts.h"
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#include "qemu/main-loop.h"
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#include "sysemu/runstate.h"
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#include "internals.h"
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#include "arm-powerctl.h"
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bool arm_is_psci_call(ARMCPU *cpu, int excp_type)
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{
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/* Return true if the r0/x0 value indicates a PSCI call and
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* the exception type matches the configured PSCI conduit. This is
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* called before the SMC/HVC instruction is executed, to decide whether
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* we should treat it as a PSCI call or with the architecturally
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* defined behaviour for an SMC or HVC (which might be UNDEF or trap
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* to EL2 or to EL3).
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*/
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CPUARMState *env = &cpu->env;
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uint64_t param = is_a64(env) ? env->xregs[0] : env->regs[0];
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switch (excp_type) {
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case EXCP_HVC:
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if (cpu->psci_conduit != QEMU_PSCI_CONDUIT_HVC) {
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return false;
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}
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break;
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case EXCP_SMC:
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if (cpu->psci_conduit != QEMU_PSCI_CONDUIT_SMC) {
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return false;
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}
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break;
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default:
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return false;
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}
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switch (param) {
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case QEMU_PSCI_0_2_FN_PSCI_VERSION:
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case QEMU_PSCI_0_2_FN_MIGRATE_INFO_TYPE:
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case QEMU_PSCI_0_2_FN_AFFINITY_INFO:
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case QEMU_PSCI_0_2_FN64_AFFINITY_INFO:
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case QEMU_PSCI_0_2_FN_SYSTEM_RESET:
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case QEMU_PSCI_0_2_FN_SYSTEM_OFF:
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case QEMU_PSCI_0_1_FN_CPU_ON:
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case QEMU_PSCI_0_2_FN_CPU_ON:
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case QEMU_PSCI_0_2_FN64_CPU_ON:
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case QEMU_PSCI_0_1_FN_CPU_OFF:
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case QEMU_PSCI_0_2_FN_CPU_OFF:
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case QEMU_PSCI_0_1_FN_CPU_SUSPEND:
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case QEMU_PSCI_0_2_FN_CPU_SUSPEND:
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case QEMU_PSCI_0_2_FN64_CPU_SUSPEND:
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case QEMU_PSCI_0_1_FN_MIGRATE:
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case QEMU_PSCI_0_2_FN_MIGRATE:
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return true;
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default:
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return false;
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}
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}
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void arm_handle_psci_call(ARMCPU *cpu)
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{
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/*
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* This function partially implements the logic for dispatching Power State
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* Coordination Interface (PSCI) calls (as described in ARM DEN 0022B.b),
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* to the extent required for bringing up and taking down secondary cores,
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* and for handling reset and poweroff requests.
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* Additional information about the calling convention used is available in
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* the document 'SMC Calling Convention' (ARM DEN 0028)
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*/
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CPUARMState *env = &cpu->env;
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uint64_t param[4];
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uint64_t context_id, mpidr;
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target_ulong entry;
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int32_t ret = 0;
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int i;
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for (i = 0; i < 4; i++) {
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/*
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* All PSCI functions take explicit 32-bit or native int sized
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* arguments so we can simply zero-extend all arguments regardless
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* of which exact function we are about to call.
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*/
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param[i] = is_a64(env) ? env->xregs[i] : env->regs[i];
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}
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if ((param[0] & QEMU_PSCI_0_2_64BIT) && !is_a64(env)) {
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ret = QEMU_PSCI_RET_INVALID_PARAMS;
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goto err;
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}
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switch (param[0]) {
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CPUState *target_cpu_state;
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ARMCPU *target_cpu;
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case QEMU_PSCI_0_2_FN_PSCI_VERSION:
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ret = QEMU_PSCI_0_2_RET_VERSION_0_2;
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break;
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case QEMU_PSCI_0_2_FN_MIGRATE_INFO_TYPE:
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ret = QEMU_PSCI_0_2_RET_TOS_MIGRATION_NOT_REQUIRED; /* No trusted OS */
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break;
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case QEMU_PSCI_0_2_FN_AFFINITY_INFO:
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case QEMU_PSCI_0_2_FN64_AFFINITY_INFO:
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mpidr = param[1];
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switch (param[2]) {
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case 0:
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target_cpu_state = arm_get_cpu_by_id(mpidr);
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if (!target_cpu_state) {
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ret = QEMU_PSCI_RET_INVALID_PARAMS;
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break;
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}
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target_cpu = ARM_CPU(target_cpu_state);
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g_assert(qemu_mutex_iothread_locked());
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ret = target_cpu->power_state;
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break;
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default:
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/* Everything above affinity level 0 is always on. */
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ret = 0;
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}
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break;
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case QEMU_PSCI_0_2_FN_SYSTEM_RESET:
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qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
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/* QEMU reset and shutdown are async requests, but PSCI
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* mandates that we never return from the reset/shutdown
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* call, so power the CPU off now so it doesn't execute
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* anything further.
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*/
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goto cpu_off;
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case QEMU_PSCI_0_2_FN_SYSTEM_OFF:
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qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
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goto cpu_off;
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case QEMU_PSCI_0_1_FN_CPU_ON:
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case QEMU_PSCI_0_2_FN_CPU_ON:
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case QEMU_PSCI_0_2_FN64_CPU_ON:
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{
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/* The PSCI spec mandates that newly brought up CPUs start
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* in the highest exception level which exists and is enabled
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* on the calling CPU. Since the QEMU PSCI implementation is
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* acting as a "fake EL3" or "fake EL2" firmware, this for us
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* means that we want to start at the highest NS exception level
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* that we are providing to the guest.
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* The execution mode should be that which is currently in use
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* by the same exception level on the calling CPU.
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* The CPU should be started with the context_id value
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* in x0 (if AArch64) or r0 (if AArch32).
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*/
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int target_el = arm_feature(env, ARM_FEATURE_EL2) ? 2 : 1;
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bool target_aarch64 = arm_el_is_aa64(env, target_el);
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mpidr = param[1];
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entry = param[2];
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context_id = param[3];
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ret = arm_set_cpu_on(mpidr, entry, context_id,
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target_el, target_aarch64);
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break;
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}
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case QEMU_PSCI_0_1_FN_CPU_OFF:
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case QEMU_PSCI_0_2_FN_CPU_OFF:
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goto cpu_off;
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case QEMU_PSCI_0_1_FN_CPU_SUSPEND:
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case QEMU_PSCI_0_2_FN_CPU_SUSPEND:
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case QEMU_PSCI_0_2_FN64_CPU_SUSPEND:
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/* Affinity levels are not supported in QEMU */
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if (param[1] & 0xfffe0000) {
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ret = QEMU_PSCI_RET_INVALID_PARAMS;
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break;
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}
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/* Powerdown is not supported, we always go into WFI */
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if (is_a64(env)) {
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env->xregs[0] = 0;
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} else {
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env->regs[0] = 0;
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}
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helper_wfi(env, 4);
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break;
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case QEMU_PSCI_0_1_FN_MIGRATE:
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case QEMU_PSCI_0_2_FN_MIGRATE:
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ret = QEMU_PSCI_RET_NOT_SUPPORTED;
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break;
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default:
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g_assert_not_reached();
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}
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err:
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if (is_a64(env)) {
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env->xregs[0] = ret;
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} else {
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env->regs[0] = ret;
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}
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return;
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cpu_off:
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ret = arm_set_cpu_off(cpu->mp_affinity);
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/* notreached */
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/* sanity check in case something failed */
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assert(ret == QEMU_ARM_POWERCTL_RET_SUCCESS);
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}
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