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/*
* linux/arch/arm/kernel/smp.c
*
* Copyright (C) 2002 ARM Limited, All Rights Reserved.
*
* 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.
*/
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/cache.h>
#include <linux/profile.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/cpu.h>
#include <linux/seq_file.h>
#include <linux/irq.h>
#include <linux/percpu.h>
#include <linux/clockchips.h>
#include <linux/completion.h>
#include <linux/cpufreq.h>
#include <linux/atomic.h>
#include <asm/smp.h>
#include <asm/cacheflush.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/exception.h>
#include <asm/idmap.h>
#include <asm/topology.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
#include <asm/sections.h>
#include <asm/tlbflush.h>
#include <asm/ptrace.h>
#include <asm/smp_plat.h>
#include <asm/virt.h>
#include <asm/mach/arch.h>
#include <asm/mpu.h>
/*
* as from 2.5, kernels no longer have an init_tasks structure
* so we need some other way of telling a new secondary core
* where to place its SVC stack
*/
struct secondary_data secondary_data;
/*
* control for which core is the next to come out of the secondary
* boot "holding pen"
*/
volatile int pen_release = -1;
enum ipi_msg_type {
IPI_WAKEUP,
IPI_TIMER,
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_CALL_FUNC_SINGLE,
IPI_CPU_STOP,
IPI_COMPLETION,
};
static DECLARE_COMPLETION(cpu_running);
static struct smp_operations smp_ops;
void __init smp_set_ops(struct smp_operations *ops)
{
if (ops)
smp_ops = *ops;
};
static unsigned long get_arch_pgd(pgd_t *pgd)
{
phys_addr_t pgdir = virt_to_phys(pgd);
BUG_ON(pgdir & ARCH_PGD_MASK);
return pgdir >> ARCH_PGD_SHIFT;
}
int __cpu_up(unsigned int cpu, struct task_struct *idle)
{
int ret;
/*
* We need to tell the secondary core where to find
* its stack and the page tables.
*/
secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
#ifdef CONFIG_ARM_MPU
secondary_data.mpu_rgn_szr = mpu_rgn_info.rgns[MPU_RAM_REGION].drsr;
#endif
#ifdef CONFIG_MMU
secondary_data.pgdir = get_arch_pgd(idmap_pgd);
secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
#endif
__cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
/*
* Now bring the CPU into our world.
*/
ret = boot_secondary(cpu, idle);
if (ret == 0) {
/*
* CPU was successfully started, wait for it
* to come online or time out.
*/
wait_for_completion_timeout(&cpu_running,
msecs_to_jiffies(1000));
if (!cpu_online(cpu)) {
pr_crit("CPU%u: failed to come online\n", cpu);
ret = -EIO;
}
} else {
pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
}
memset(&secondary_data, 0, sizeof(secondary_data));
return ret;
}
/* platform specific SMP operations */
void __init smp_init_cpus(void)
{
if (smp_ops.smp_init_cpus)
smp_ops.smp_init_cpus();
}
int boot_secondary(unsigned int cpu, struct task_struct *idle)
{
if (smp_ops.smp_boot_secondary)
return smp_ops.smp_boot_secondary(cpu, idle);
return -ENOSYS;
}
int platform_can_cpu_hotplug(void)
{
#ifdef CONFIG_HOTPLUG_CPU
if (smp_ops.cpu_kill)
return 1;
#endif
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
static int platform_cpu_kill(unsigned int cpu)
{
if (smp_ops.cpu_kill)
return smp_ops.cpu_kill(cpu);
return 1;
}
static int platform_cpu_disable(unsigned int cpu)
{
if (smp_ops.cpu_disable)
return smp_ops.cpu_disable(cpu);
/*
* By default, allow disabling all CPUs except the first one,
* since this is special on a lot of platforms, e.g. because
* of clock tick interrupts.
*/
return cpu == 0 ? -EPERM : 0;
}
/*
* __cpu_disable runs on the processor to be shutdown.
*/
int __cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
int ret;
ret = platform_cpu_disable(cpu);
if (ret)
return ret;
/*
* Take this CPU offline. Once we clear this, we can't return,
* and we must not schedule until we're ready to give up the cpu.
*/
set_cpu_online(cpu, false);
/*
* OK - migrate IRQs away from this CPU
*/
migrate_irqs();
/*
* Flush user cache and TLB mappings, and then remove this CPU
* from the vm mask set of all processes.
*
* Caches are flushed to the Level of Unification Inner Shareable
* to write-back dirty lines to unified caches shared by all CPUs.
*/
flush_cache_louis();
local_flush_tlb_all();
clear_tasks_mm_cpumask(cpu);
return 0;
}
static DECLARE_COMPLETION(cpu_died);
/*
* called on the thread which is asking for a CPU to be shutdown -
* waits until shutdown has completed, or it is timed out.
*/
void __cpu_die(unsigned int cpu)
{
if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
pr_err("CPU%u: cpu didn't die\n", cpu);
return;
}
printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
/*
* platform_cpu_kill() is generally expected to do the powering off
* and/or cutting of clocks to the dying CPU. Optionally, this may
* be done by the CPU which is dying in preference to supporting
* this call, but that means there is _no_ synchronisation between
* the requesting CPU and the dying CPU actually losing power.
*/
if (!platform_cpu_kill(cpu))
printk("CPU%u: unable to kill\n", cpu);
}
/*
* Called from the idle thread for the CPU which has been shutdown.
*
* Note that we disable IRQs here, but do not re-enable them
* before returning to the caller. This is also the behaviour
* of the other hotplug-cpu capable cores, so presumably coming
* out of idle fixes this.
*/
void __ref cpu_die(void)
{
unsigned int cpu = smp_processor_id();
idle_task_exit();
local_irq_disable();
/*
* Flush the data out of the L1 cache for this CPU. This must be
* before the completion to ensure that data is safely written out
* before platform_cpu_kill() gets called - which may disable
* *this* CPU and power down its cache.
*/
flush_cache_louis();
/*
* Tell __cpu_die() that this CPU is now safe to dispose of. Once
* this returns, power and/or clocks can be removed at any point
* from this CPU and its cache by platform_cpu_kill().
*/
complete(&cpu_died);
/*
* Ensure that the cache lines associated with that completion are
* written out. This covers the case where _this_ CPU is doing the
* powering down, to ensure that the completion is visible to the
* CPU waiting for this one.
*/
flush_cache_louis();
/*
* The actual CPU shutdown procedure is at least platform (if not
* CPU) specific. This may remove power, or it may simply spin.
*
* Platforms are generally expected *NOT* to return from this call,
* although there are some which do because they have no way to
* power down the CPU. These platforms are the _only_ reason we
* have a return path which uses the fragment of assembly below.
*
* The return path should not be used for platforms which can
* power off the CPU.
*/
if (smp_ops.cpu_die)
smp_ops.cpu_die(cpu);
/*
* Do not return to the idle loop - jump back to the secondary
* cpu initialisation. There's some initialisation which needs
* to be repeated to undo the effects of taking the CPU offline.
*/
__asm__("mov sp, %0\n"
" mov fp, #0\n"
" b secondary_start_kernel"
:
: "r" (task_stack_page(current) + THREAD_SIZE - 8));
}
#endif /* CONFIG_HOTPLUG_CPU */
/*
* Called by both boot and secondaries to move global data into
* per-processor storage.
*/
static void smp_store_cpu_info(unsigned int cpuid)
{
struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
cpu_info->loops_per_jiffy = loops_per_jiffy;
cpu_info->cpuid = read_cpuid_id();
store_cpu_topology(cpuid);
}
/*
* This is the secondary CPU boot entry. We're using this CPUs
* idle thread stack, but a set of temporary page tables.
*/
asmlinkage void secondary_start_kernel(void)
{
struct mm_struct *mm = &init_mm;
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