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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psci_smp.c (2909B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *
      4 * Copyright (C) 2012 ARM Limited
      5 *
      6 * Author: Will Deacon <will.deacon@arm.com>
      7 */
      8
      9#include <linux/init.h>
     10#include <linux/smp.h>
     11#include <linux/of.h>
     12#include <linux/delay.h>
     13#include <linux/psci.h>
     14
     15#include <uapi/linux/psci.h>
     16
     17#include <asm/psci.h>
     18#include <asm/smp_plat.h>
     19
     20/*
     21 * psci_smp assumes that the following is true about PSCI:
     22 *
     23 * cpu_suspend   Suspend the execution on a CPU
     24 * @state        we don't currently describe affinity levels, so just pass 0.
     25 * @entry_point  the first instruction to be executed on return
     26 * returns 0  success, < 0 on failure
     27 *
     28 * cpu_off       Power down a CPU
     29 * @state        we don't currently describe affinity levels, so just pass 0.
     30 * no return on successful call
     31 *
     32 * cpu_on        Power up a CPU
     33 * @cpuid        cpuid of target CPU, as from MPIDR
     34 * @entry_point  the first instruction to be executed on return
     35 * returns 0  success, < 0 on failure
     36 *
     37 * migrate       Migrate the context to a different CPU
     38 * @cpuid        cpuid of target CPU, as from MPIDR
     39 * returns 0  success, < 0 on failure
     40 *
     41 */
     42
     43extern void secondary_startup(void);
     44
     45static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
     46{
     47	if (psci_ops.cpu_on)
     48		return psci_ops.cpu_on(cpu_logical_map(cpu),
     49					virt_to_idmap(&secondary_startup));
     50	return -ENODEV;
     51}
     52
     53#ifdef CONFIG_HOTPLUG_CPU
     54static int psci_cpu_disable(unsigned int cpu)
     55{
     56	/* Fail early if we don't have CPU_OFF support */
     57	if (!psci_ops.cpu_off)
     58		return -EOPNOTSUPP;
     59
     60	/* Trusted OS will deny CPU_OFF */
     61	if (psci_tos_resident_on(cpu))
     62		return -EPERM;
     63
     64	return 0;
     65}
     66
     67static void psci_cpu_die(unsigned int cpu)
     68{
     69	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
     70		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
     71
     72	if (psci_ops.cpu_off)
     73		psci_ops.cpu_off(state);
     74
     75	/* We should never return */
     76	panic("psci: cpu %d failed to shutdown\n", cpu);
     77}
     78
     79static int psci_cpu_kill(unsigned int cpu)
     80{
     81	int err, i;
     82
     83	if (!psci_ops.affinity_info)
     84		return 1;
     85	/*
     86	 * cpu_kill could race with cpu_die and we can
     87	 * potentially end up declaring this cpu undead
     88	 * while it is dying. So, try again a few times.
     89	 */
     90
     91	for (i = 0; i < 10; i++) {
     92		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
     93		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
     94			pr_info("CPU%d killed.\n", cpu);
     95			return 1;
     96		}
     97
     98		msleep(10);
     99		pr_info("Retrying again to check for CPU kill\n");
    100	}
    101
    102	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
    103			cpu, err);
    104	/* Make platform_cpu_kill() fail. */
    105	return 0;
    106}
    107
    108#endif
    109
    110bool __init psci_smp_available(void)
    111{
    112	/* is cpu_on available at least? */
    113	return (psci_ops.cpu_on != NULL);
    114}
    115
    116const struct smp_operations psci_smp_ops __initconst = {
    117	.smp_boot_secondary	= psci_boot_secondary,
    118#ifdef CONFIG_HOTPLUG_CPU
    119	.cpu_disable		= psci_cpu_disable,
    120	.cpu_die		= psci_cpu_die,
    121	.cpu_kill		= psci_cpu_kill,
    122#endif
    123};