mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 11:06:39 +07:00
c814ca029e
PSCIv0.2 adds a new function called AFFINITY_INFO, which can be used to query if a specified CPU has actually gone offline. Calling this function via cpu_kill ensures that a CPU has quiesced after a call to cpu_die. This helps prevent the CPU from doing arbitrary bad things when data or instructions are clobbered (as happens with kexec) in the window between a CPU announcing that it is dead and said CPU leaving the kernel. Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Rob Herring <robh@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
116 lines
3.0 KiB
C
116 lines
3.0 KiB
C
/*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* Copyright (C) 2012 ARM Limited
|
|
*
|
|
* Author: Will Deacon <will.deacon@arm.com>
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/of.h>
|
|
#include <linux/delay.h>
|
|
#include <uapi/linux/psci.h>
|
|
|
|
#include <asm/psci.h>
|
|
#include <asm/smp_plat.h>
|
|
|
|
/*
|
|
* psci_smp assumes that the following is true about PSCI:
|
|
*
|
|
* cpu_suspend Suspend the execution on a CPU
|
|
* @state we don't currently describe affinity levels, so just pass 0.
|
|
* @entry_point the first instruction to be executed on return
|
|
* returns 0 success, < 0 on failure
|
|
*
|
|
* cpu_off Power down a CPU
|
|
* @state we don't currently describe affinity levels, so just pass 0.
|
|
* no return on successful call
|
|
*
|
|
* cpu_on Power up a CPU
|
|
* @cpuid cpuid of target CPU, as from MPIDR
|
|
* @entry_point the first instruction to be executed on return
|
|
* returns 0 success, < 0 on failure
|
|
*
|
|
* migrate Migrate the context to a different CPU
|
|
* @cpuid cpuid of target CPU, as from MPIDR
|
|
* returns 0 success, < 0 on failure
|
|
*
|
|
*/
|
|
|
|
extern void secondary_startup(void);
|
|
|
|
static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
|
|
{
|
|
if (psci_ops.cpu_on)
|
|
return psci_ops.cpu_on(cpu_logical_map(cpu),
|
|
__pa(secondary_startup));
|
|
return -ENODEV;
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
void __ref psci_cpu_die(unsigned int cpu)
|
|
{
|
|
const struct psci_power_state ps = {
|
|
.type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
|
|
};
|
|
|
|
if (psci_ops.cpu_off)
|
|
psci_ops.cpu_off(ps);
|
|
|
|
/* We should never return */
|
|
panic("psci: cpu %d failed to shutdown\n", cpu);
|
|
}
|
|
|
|
int __ref psci_cpu_kill(unsigned int cpu)
|
|
{
|
|
int err, i;
|
|
|
|
if (!psci_ops.affinity_info)
|
|
return 1;
|
|
/*
|
|
* cpu_kill could race with cpu_die and we can
|
|
* potentially end up declaring this cpu undead
|
|
* while it is dying. So, try again a few times.
|
|
*/
|
|
|
|
for (i = 0; i < 10; i++) {
|
|
err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
|
|
if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
|
|
pr_info("CPU%d killed.\n", cpu);
|
|
return 1;
|
|
}
|
|
|
|
msleep(10);
|
|
pr_info("Retrying again to check for CPU kill\n");
|
|
}
|
|
|
|
pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
|
|
cpu, err);
|
|
/* Make platform_cpu_kill() fail. */
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
bool __init psci_smp_available(void)
|
|
{
|
|
/* is cpu_on available at least? */
|
|
return (psci_ops.cpu_on != NULL);
|
|
}
|
|
|
|
struct smp_operations __initdata psci_smp_ops = {
|
|
.smp_boot_secondary = psci_boot_secondary,
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
.cpu_die = psci_cpu_die,
|
|
.cpu_kill = psci_cpu_kill,
|
|
#endif
|
|
};
|