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-arm.c (4092B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * ARM/ARM64 generic CPU idle driver.
      4 *
      5 * Copyright (C) 2014 ARM Ltd.
      6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
      7 */
      8
      9#define pr_fmt(fmt) "CPUidle arm: " fmt
     10
     11#include <linux/cpu_cooling.h>
     12#include <linux/cpuidle.h>
     13#include <linux/cpumask.h>
     14#include <linux/cpu_pm.h>
     15#include <linux/kernel.h>
     16#include <linux/module.h>
     17#include <linux/of.h>
     18#include <linux/slab.h>
     19
     20#include <asm/cpuidle.h>
     21
     22#include "dt_idle_states.h"
     23
     24/*
     25 * arm_enter_idle_state - Programs CPU to enter the specified state
     26 *
     27 * dev: cpuidle device
     28 * drv: cpuidle driver
     29 * idx: state index
     30 *
     31 * Called from the CPUidle framework to program the device to the
     32 * specified target state selected by the governor.
     33 */
     34static int arm_enter_idle_state(struct cpuidle_device *dev,
     35				struct cpuidle_driver *drv, int idx)
     36{
     37	/*
     38	 * Pass idle state index to arm_cpuidle_suspend which in turn
     39	 * will call the CPU ops suspend protocol with idle index as a
     40	 * parameter.
     41	 */
     42	return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx);
     43}
     44
     45static struct cpuidle_driver arm_idle_driver __initdata = {
     46	.name = "arm_idle",
     47	.owner = THIS_MODULE,
     48	/*
     49	 * State at index 0 is standby wfi and considered standard
     50	 * on all ARM platforms. If in some platforms simple wfi
     51	 * can't be used as "state 0", DT bindings must be implemented
     52	 * to work around this issue and allow installing a special
     53	 * handler for idle state index 0.
     54	 */
     55	.states[0] = {
     56		.enter                  = arm_enter_idle_state,
     57		.exit_latency           = 1,
     58		.target_residency       = 1,
     59		.power_usage		= UINT_MAX,
     60		.name                   = "WFI",
     61		.desc                   = "ARM WFI",
     62	}
     63};
     64
     65static const struct of_device_id arm_idle_state_match[] __initconst = {
     66	{ .compatible = "arm,idle-state",
     67	  .data = arm_enter_idle_state },
     68	{ },
     69};
     70
     71/*
     72 * arm_idle_init_cpu
     73 *
     74 * Registers the arm specific cpuidle driver with the cpuidle
     75 * framework. It relies on core code to parse the idle states
     76 * and initialize them using driver data structures accordingly.
     77 */
     78static int __init arm_idle_init_cpu(int cpu)
     79{
     80	int ret;
     81	struct cpuidle_driver *drv;
     82
     83	drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);
     84	if (!drv)
     85		return -ENOMEM;
     86
     87	drv->cpumask = (struct cpumask *)cpumask_of(cpu);
     88
     89	/*
     90	 * Initialize idle states data, starting at index 1.  This
     91	 * driver is DT only, if no DT idle states are detected (ret
     92	 * == 0) let the driver initialization fail accordingly since
     93	 * there is no reason to initialize the idle driver if only
     94	 * wfi is supported.
     95	 */
     96	ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);
     97	if (ret <= 0) {
     98		ret = ret ? : -ENODEV;
     99		goto out_kfree_drv;
    100	}
    101
    102	/*
    103	 * Call arch CPU operations in order to initialize
    104	 * idle states suspend back-end specific data
    105	 */
    106	ret = arm_cpuidle_init(cpu);
    107
    108	/*
    109	 * Allow the initialization to continue for other CPUs, if the
    110	 * reported failure is a HW misconfiguration/breakage (-ENXIO).
    111	 *
    112	 * Some platforms do not support idle operations
    113	 * (arm_cpuidle_init() returning -EOPNOTSUPP), we should
    114	 * not flag this case as an error, it is a valid
    115	 * configuration.
    116	 */
    117	if (ret) {
    118		if (ret != -EOPNOTSUPP)
    119			pr_err("CPU %d failed to init idle CPU ops\n", cpu);
    120		ret = ret == -ENXIO ? 0 : ret;
    121		goto out_kfree_drv;
    122	}
    123
    124	ret = cpuidle_register(drv, NULL);
    125	if (ret)
    126		goto out_kfree_drv;
    127
    128	cpuidle_cooling_register(drv);
    129
    130	return 0;
    131
    132out_kfree_drv:
    133	kfree(drv);
    134	return ret;
    135}
    136
    137/*
    138 * arm_idle_init - Initializes arm cpuidle driver
    139 *
    140 * Initializes arm cpuidle driver for all CPUs, if any CPU fails
    141 * to register cpuidle driver then rollback to cancel all CPUs
    142 * registeration.
    143 */
    144static int __init arm_idle_init(void)
    145{
    146	int cpu, ret;
    147	struct cpuidle_driver *drv;
    148	struct cpuidle_device *dev;
    149
    150	for_each_possible_cpu(cpu) {
    151		ret = arm_idle_init_cpu(cpu);
    152		if (ret)
    153			goto out_fail;
    154	}
    155
    156	return 0;
    157
    158out_fail:
    159	while (--cpu >= 0) {
    160		dev = per_cpu(cpuidle_devices, cpu);
    161		drv = cpuidle_get_cpu_driver(dev);
    162		cpuidle_unregister(drv);
    163		kfree(drv);
    164	}
    165
    166	return ret;
    167}
    168device_initcall(arm_idle_init);