cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cpuidle.c (2399B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * ARM64 CPU idle arch support
      4 *
      5 * Copyright (C) 2014 ARM Ltd.
      6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
      7 */
      8
      9#include <linux/acpi.h>
     10#include <linux/cpuidle.h>
     11#include <linux/cpu_pm.h>
     12#include <linux/of.h>
     13#include <linux/of_device.h>
     14#include <linux/psci.h>
     15
     16#include <asm/cpuidle.h>
     17#include <asm/cpu_ops.h>
     18
     19int arm_cpuidle_init(unsigned int cpu)
     20{
     21	const struct cpu_operations *ops = get_cpu_ops(cpu);
     22	int ret = -EOPNOTSUPP;
     23
     24	if (ops && ops->cpu_suspend && ops->cpu_init_idle)
     25		ret = ops->cpu_init_idle(cpu);
     26
     27	return ret;
     28}
     29
     30/**
     31 * arm_cpuidle_suspend() - function to enter a low-power idle state
     32 * @index: argument to pass to CPU suspend operations
     33 *
     34 * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
     35 * operations back-end error code otherwise.
     36 */
     37int arm_cpuidle_suspend(int index)
     38{
     39	int cpu = smp_processor_id();
     40	const struct cpu_operations *ops = get_cpu_ops(cpu);
     41
     42	return ops->cpu_suspend(index);
     43}
     44
     45#ifdef CONFIG_ACPI
     46
     47#include <acpi/processor.h>
     48
     49#define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
     50
     51static int psci_acpi_cpu_init_idle(unsigned int cpu)
     52{
     53	int i, count;
     54	struct acpi_lpi_state *lpi;
     55	struct acpi_processor *pr = per_cpu(processors, cpu);
     56
     57	if (unlikely(!pr || !pr->flags.has_lpi))
     58		return -EINVAL;
     59
     60	/*
     61	 * If the PSCI cpu_suspend function hook has not been initialized
     62	 * idle states must not be enabled, so bail out
     63	 */
     64	if (!psci_ops.cpu_suspend)
     65		return -EOPNOTSUPP;
     66
     67	count = pr->power.count - 1;
     68	if (count <= 0)
     69		return -ENODEV;
     70
     71	for (i = 0; i < count; i++) {
     72		u32 state;
     73
     74		lpi = &pr->power.lpi_states[i + 1];
     75		/*
     76		 * Only bits[31:0] represent a PSCI power_state while
     77		 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
     78		 */
     79		state = lpi->address;
     80		if (!psci_power_state_is_valid(state)) {
     81			pr_warn("Invalid PSCI power state %#x\n", state);
     82			return -EINVAL;
     83		}
     84	}
     85
     86	return 0;
     87}
     88
     89int acpi_processor_ffh_lpi_probe(unsigned int cpu)
     90{
     91	return psci_acpi_cpu_init_idle(cpu);
     92}
     93
     94int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
     95{
     96	u32 state = lpi->address;
     97
     98	if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
     99		return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(psci_cpu_suspend_enter,
    100						lpi->index, state);
    101	else
    102		return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
    103					     lpi->index, state);
    104}
    105#endif