linux/arch/arm/kernel/smp.c
Russell King 3d3f78d752 ARM: call machine_shutdown() from machine_halt(), etc
x86 calls machine_shutdown() from the various machine_*() calls which
take the machine down ready for halting, restarting, etc, and uses
this to bring the system safely to a point where those actions can be
performed.  Such actions are stopping the secondary CPUs.

So, change the ARM implementation of these to reflect what x86 does.

This solves kexec problems on ARM SMP platforms, where the secondary
CPUs were left running across the kexec call.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-07-27 10:48:43 +01:00

704 lines
15 KiB
C

/*
* 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/smp.h>
#include <linux/seq_file.h>
#include <linux/irq.h>
#include <linux/percpu.h>
#include <linux/clockchips.h>
#include <asm/atomic.h>
#include <asm/cacheflush.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/ptrace.h>
#include <asm/localtimer.h>
#include <asm/smp_plat.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;
/*
* structures for inter-processor calls
* - A collection of single bit ipi messages.
*/
struct ipi_data {
spinlock_t lock;
unsigned long ipi_count;
unsigned long bits;
};
static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
.lock = SPIN_LOCK_UNLOCKED,
};
enum ipi_msg_type {
IPI_TIMER,
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_CALL_FUNC_SINGLE,
IPI_CPU_STOP,
};
int __cpuinit __cpu_up(unsigned int cpu)
{
struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
struct task_struct *idle = ci->idle;
pgd_t *pgd;
pmd_t *pmd;
int ret;
/*
* Spawn a new process manually, if not already done.
* Grab a pointer to its task struct so we can mess with it
*/
if (!idle) {
idle = fork_idle(cpu);
if (IS_ERR(idle)) {
printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
return PTR_ERR(idle);
}
ci->idle = idle;
} else {
/*
* Since this idle thread is being re-used, call
* init_idle() to reinitialize the thread structure.
*/
init_idle(idle, cpu);
}
/*
* Allocate initial page tables to allow the new CPU to
* enable the MMU safely. This essentially means a set
* of our "standard" page tables, with the addition of
* a 1:1 mapping for the physical address of the kernel.
*/
pgd = pgd_alloc(&init_mm);
pmd = pmd_offset(pgd + pgd_index(PHYS_OFFSET), PHYS_OFFSET);
*pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) |
PMD_TYPE_SECT | PMD_SECT_AP_WRITE);
flush_pmd_entry(pmd);
outer_clean_range(__pa(pmd), __pa(pmd + 1));
/*
* 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;
secondary_data.pgdir = virt_to_phys(pgd);
__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) {
unsigned long timeout;
/*
* CPU was successfully started, wait for it
* to come online or time out.
*/
timeout = jiffies + HZ;
while (time_before(jiffies, timeout)) {
if (cpu_online(cpu))
break;
udelay(10);
barrier();
}
if (!cpu_online(cpu))
ret = -EIO;
}
secondary_data.stack = NULL;
secondary_data.pgdir = 0;
*pmd = __pmd(0);
clean_pmd_entry(pmd);
pgd_free(&init_mm, pgd);
if (ret) {
printk(KERN_CRIT "CPU%u: processor failed to boot\n", cpu);
/*
* FIXME: We need to clean up the new idle thread. --rmk
*/
}
return ret;
}
#ifdef CONFIG_HOTPLUG_CPU
/*
* __cpu_disable runs on the processor to be shutdown.
*/
int __cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
struct task_struct *p;
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();
/*
* Stop the local timer for this CPU.
*/
local_timer_stop();
/*
* Flush user cache and TLB mappings, and then remove this CPU
* from the vm mask set of all processes.
*/
flush_cache_all();
local_flush_tlb_all();
read_lock(&tasklist_lock);
for_each_process(p) {
if (p->mm)
cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
}
read_unlock(&tasklist_lock);
return 0;
}
/*
* 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 (!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();
local_irq_disable();
idle_task_exit();
/*
* actual CPU shutdown procedure is at least platform (if not
* CPU) specific
*/
platform_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"
" b secondary_start_kernel"
:
: "r" (task_stack_page(current) + THREAD_SIZE - 8));
}
#endif /* CONFIG_HOTPLUG_CPU */
/*
* This is the secondary CPU boot entry. We're using this CPUs
* idle thread stack, but a set of temporary page tables.
*/
asmlinkage void __cpuinit secondary_start_kernel(void)
{
struct mm_struct *mm = &init_mm;
unsigned int cpu = smp_processor_id();
printk("CPU%u: Booted secondary processor\n", cpu);
/*
* All kernel threads share the same mm context; grab a
* reference and switch to it.
*/
atomic_inc(&mm->mm_users);
atomic_inc(&mm->mm_count);
current->active_mm = mm;
cpumask_set_cpu(cpu, mm_cpumask(mm));
cpu_switch_mm(mm->pgd, mm);
enter_lazy_tlb(mm, current);
local_flush_tlb_all();
cpu_init();
preempt_disable();
/*
* Give the platform a chance to do its own initialisation.
*/
platform_secondary_init(cpu);
/*
* Enable local interrupts.
*/
notify_cpu_starting(cpu);
local_irq_enable();
local_fiq_enable();
/*
* Setup the percpu timer for this CPU.
*/
percpu_timer_setup();
calibrate_delay();
smp_store_cpu_info(cpu);
/*
* OK, now it's safe to let the boot CPU continue
*/
set_cpu_online(cpu, true);
/*
* OK, it's off to the idle thread for us
*/
cpu_idle();
}
/*
* Called by both boot and secondaries to move global data into
* per-processor storage.
*/
void __cpuinit 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;
}
void __init smp_cpus_done(unsigned int max_cpus)
{
int cpu;
unsigned long bogosum = 0;
for_each_online_cpu(cpu)
bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
printk(KERN_INFO "SMP: Total of %d processors activated "
"(%lu.%02lu BogoMIPS).\n",
num_online_cpus(),
bogosum / (500000/HZ),
(bogosum / (5000/HZ)) % 100);
}
void __init smp_prepare_boot_cpu(void)
{
unsigned int cpu = smp_processor_id();
per_cpu(cpu_data, cpu).idle = current;
}
static void send_ipi_message(const struct cpumask *mask, enum ipi_msg_type msg)
{
unsigned long flags;
unsigned int cpu;
local_irq_save(flags);
for_each_cpu(cpu, mask) {
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
spin_lock(&ipi->lock);
ipi->bits |= 1 << msg;
spin_unlock(&ipi->lock);
}
/*
* Call the platform specific cross-CPU call function.
*/
smp_cross_call(mask);
local_irq_restore(flags);
}
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
send_ipi_message(mask, IPI_CALL_FUNC);
}
void arch_send_call_function_single_ipi(int cpu)
{
send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
}
void show_ipi_list(struct seq_file *p)
{
unsigned int cpu;
seq_puts(p, "IPI:");
for_each_present_cpu(cpu)
seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
seq_putc(p, '\n');
}
void show_local_irqs(struct seq_file *p)
{
unsigned int cpu;
seq_printf(p, "LOC: ");
for_each_present_cpu(cpu)
seq_printf(p, "%10u ", irq_stat[cpu].local_timer_irqs);
seq_putc(p, '\n');
}
/*
* Timer (local or broadcast) support
*/
static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
static void ipi_timer(void)
{
struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
irq_enter();
evt->event_handler(evt);
irq_exit();
}
#ifdef CONFIG_LOCAL_TIMERS
asmlinkage void __exception do_local_timer(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
int cpu = smp_processor_id();
if (local_timer_ack()) {
irq_stat[cpu].local_timer_irqs++;
ipi_timer();
}
set_irq_regs(old_regs);
}
#endif
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
static void smp_timer_broadcast(const struct cpumask *mask)
{
send_ipi_message(mask, IPI_TIMER);
}
#else
#define smp_timer_broadcast NULL
#endif
#ifndef CONFIG_LOCAL_TIMERS
static void broadcast_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
}
static void local_timer_setup(struct clock_event_device *evt)
{
evt->name = "dummy_timer";
evt->features = CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_DUMMY;
evt->rating = 400;
evt->mult = 1;
evt->set_mode = broadcast_timer_set_mode;
clockevents_register_device(evt);
}
#endif
void __cpuinit percpu_timer_setup(void)
{
unsigned int cpu = smp_processor_id();
struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
evt->cpumask = cpumask_of(cpu);
evt->broadcast = smp_timer_broadcast;
local_timer_setup(evt);
}
static DEFINE_SPINLOCK(stop_lock);
/*
* ipi_cpu_stop - handle IPI from smp_send_stop()
*/
static void ipi_cpu_stop(unsigned int cpu)
{
if (system_state == SYSTEM_BOOTING ||
system_state == SYSTEM_RUNNING) {
spin_lock(&stop_lock);
printk(KERN_CRIT "CPU%u: stopping\n", cpu);
dump_stack();
spin_unlock(&stop_lock);
}
set_cpu_online(cpu, false);
local_fiq_disable();
local_irq_disable();
while (1)
cpu_relax();
}
/*
* Main handler for inter-processor interrupts
*
* For ARM, the ipimask now only identifies a single
* category of IPI (Bit 1 IPIs have been replaced by a
* different mechanism):
*
* Bit 0 - Inter-processor function call
*/
asmlinkage void __exception do_IPI(struct pt_regs *regs)
{
unsigned int cpu = smp_processor_id();
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
struct pt_regs *old_regs = set_irq_regs(regs);
ipi->ipi_count++;
for (;;) {
unsigned long msgs;
spin_lock(&ipi->lock);
msgs = ipi->bits;
ipi->bits = 0;
spin_unlock(&ipi->lock);
if (!msgs)
break;
do {
unsigned nextmsg;
nextmsg = msgs & -msgs;
msgs &= ~nextmsg;
nextmsg = ffz(~nextmsg);
switch (nextmsg) {
case IPI_TIMER:
ipi_timer();
break;
case IPI_RESCHEDULE:
/*
* nothing more to do - eveything is
* done on the interrupt return path
*/
break;
case IPI_CALL_FUNC:
generic_smp_call_function_interrupt();
break;
case IPI_CALL_FUNC_SINGLE:
generic_smp_call_function_single_interrupt();
break;
case IPI_CPU_STOP:
ipi_cpu_stop(cpu);
break;
default:
printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
cpu, nextmsg);
break;
}
} while (msgs);
}
set_irq_regs(old_regs);
}
void smp_send_reschedule(int cpu)
{
send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
}
void smp_send_stop(void)
{
cpumask_t mask = cpu_online_map;
cpu_clear(smp_processor_id(), mask);
send_ipi_message(&mask, IPI_CPU_STOP);
}
/*
* not supported here
*/
int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
static void
on_each_cpu_mask(void (*func)(void *), void *info, int wait,
const struct cpumask *mask)
{
preempt_disable();
smp_call_function_many(mask, func, info, wait);
if (cpumask_test_cpu(smp_processor_id(), mask))
func(info);
preempt_enable();
}
/**********************************************************************/
/*
* TLB operations
*/
struct tlb_args {
struct vm_area_struct *ta_vma;
unsigned long ta_start;
unsigned long ta_end;
};
static inline void ipi_flush_tlb_all(void *ignored)
{
local_flush_tlb_all();
}
static inline void ipi_flush_tlb_mm(void *arg)
{
struct mm_struct *mm = (struct mm_struct *)arg;
local_flush_tlb_mm(mm);
}
static inline void ipi_flush_tlb_page(void *arg)
{
struct tlb_args *ta = (struct tlb_args *)arg;
local_flush_tlb_page(ta->ta_vma, ta->ta_start);
}
static inline void ipi_flush_tlb_kernel_page(void *arg)
{
struct tlb_args *ta = (struct tlb_args *)arg;
local_flush_tlb_kernel_page(ta->ta_start);
}
static inline void ipi_flush_tlb_range(void *arg)
{
struct tlb_args *ta = (struct tlb_args *)arg;
local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
}
static inline void ipi_flush_tlb_kernel_range(void *arg)
{
struct tlb_args *ta = (struct tlb_args *)arg;
local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end);
}
void flush_tlb_all(void)
{
if (tlb_ops_need_broadcast())
on_each_cpu(ipi_flush_tlb_all, NULL, 1);
else
local_flush_tlb_all();
}
void flush_tlb_mm(struct mm_struct *mm)
{
if (tlb_ops_need_broadcast())
on_each_cpu_mask(ipi_flush_tlb_mm, mm, 1, mm_cpumask(mm));
else
local_flush_tlb_mm(mm);
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
{
if (tlb_ops_need_broadcast()) {
struct tlb_args ta;
ta.ta_vma = vma;
ta.ta_start = uaddr;
on_each_cpu_mask(ipi_flush_tlb_page, &ta, 1, mm_cpumask(vma->vm_mm));
} else
local_flush_tlb_page(vma, uaddr);
}
void flush_tlb_kernel_page(unsigned long kaddr)
{
if (tlb_ops_need_broadcast()) {
struct tlb_args ta;
ta.ta_start = kaddr;
on_each_cpu(ipi_flush_tlb_kernel_page, &ta, 1);
} else
local_flush_tlb_kernel_page(kaddr);
}
void flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
if (tlb_ops_need_broadcast()) {
struct tlb_args ta;
ta.ta_vma = vma;
ta.ta_start = start;
ta.ta_end = end;
on_each_cpu_mask(ipi_flush_tlb_range, &ta, 1, mm_cpumask(vma->vm_mm));
} else
local_flush_tlb_range(vma, start, end);
}
void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
if (tlb_ops_need_broadcast()) {
struct tlb_args ta;
ta.ta_start = start;
ta.ta_end = end;
on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1);
} else
local_flush_tlb_kernel_range(start, end);
}