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cpu_psci_cpu_die() is called in the context of the dying CPU, which will no longer be online or tracked by RCU. It is therefore not generally safe to call printk() if the PSCI "cpu off" request fails, so remove the pr_crit() invocation. Cc: Qian Cai <cai@redhat.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20201106103602.9849-2-will@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
123 lines
2.6 KiB
C
123 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Copyright (C) 2013 ARM Limited
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*
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* Author: Will Deacon <will.deacon@arm.com>
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*/
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#define pr_fmt(fmt) "psci: " fmt
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#include <linux/init.h>
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#include <linux/of.h>
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#include <linux/smp.h>
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#include <linux/delay.h>
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#include <linux/psci.h>
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#include <linux/mm.h>
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#include <uapi/linux/psci.h>
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#include <asm/cpu_ops.h>
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#include <asm/errno.h>
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#include <asm/smp_plat.h>
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static int __init cpu_psci_cpu_init(unsigned int cpu)
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{
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return 0;
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}
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static int __init cpu_psci_cpu_prepare(unsigned int cpu)
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{
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if (!psci_ops.cpu_on) {
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pr_err("no cpu_on method, not booting CPU%d\n", cpu);
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return -ENODEV;
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}
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return 0;
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}
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static int cpu_psci_cpu_boot(unsigned int cpu)
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{
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int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry));
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if (err)
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pr_err("failed to boot CPU%d (%d)\n", cpu, err);
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return err;
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static bool cpu_psci_cpu_can_disable(unsigned int cpu)
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{
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return !psci_tos_resident_on(cpu);
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}
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static int cpu_psci_cpu_disable(unsigned int cpu)
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{
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/* Fail early if we don't have CPU_OFF support */
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if (!psci_ops.cpu_off)
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return -EOPNOTSUPP;
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/* Trusted OS will deny CPU_OFF */
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if (psci_tos_resident_on(cpu))
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return -EPERM;
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return 0;
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}
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static void cpu_psci_cpu_die(unsigned int cpu)
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{
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/*
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* There are no known implementations of PSCI actually using the
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* power state field, pass a sensible default for now.
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*/
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u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
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PSCI_0_2_POWER_STATE_TYPE_SHIFT;
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psci_ops.cpu_off(state);
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}
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static int cpu_psci_cpu_kill(unsigned int cpu)
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{
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int err;
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unsigned long start, end;
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if (!psci_ops.affinity_info)
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return 0;
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/*
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* cpu_kill could race with cpu_die and we can
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* potentially end up declaring this cpu undead
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* while it is dying. So, try again a few times.
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*/
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start = jiffies;
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end = start + msecs_to_jiffies(100);
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do {
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err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
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if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
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pr_info("CPU%d killed (polled %d ms)\n", cpu,
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jiffies_to_msecs(jiffies - start));
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return 0;
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}
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usleep_range(100, 1000);
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} while (time_before(jiffies, end));
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pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
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cpu, err);
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return -ETIMEDOUT;
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}
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#endif
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const struct cpu_operations cpu_psci_ops = {
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.name = "psci",
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.cpu_init = cpu_psci_cpu_init,
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.cpu_prepare = cpu_psci_cpu_prepare,
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.cpu_boot = cpu_psci_cpu_boot,
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#ifdef CONFIG_HOTPLUG_CPU
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.cpu_can_disable = cpu_psci_cpu_can_disable,
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.cpu_disable = cpu_psci_cpu_disable,
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.cpu_die = cpu_psci_cpu_die,
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.cpu_kill = cpu_psci_cpu_kill,
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#endif
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};
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