/*
* 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/config.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/cpu.h>
#include <linux/smp.h>
#include <linux/seq_file.h>
#include <asm/atomic.h>
#include <asm/cacheflush.h>
#include <asm/cpu.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>
/*
* bitmask of present and online CPUs.
* The present bitmask indicates that the CPU is physically present.
* The online bitmask indicates that the CPU is up and running.
*/
cpumask_t cpu_present_mask;
cpumask_t cpu_online_map;
/*
* 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_CPU_STOP,
};
struct smp_call_struct {
void (*func)(void *info);
void *info;
int wait;
cpumask_t pending;
cpumask_t unfinished;
};
static struct smp_call_struct * volatile smp_call_function_data;
static DEFINE_SPINLOCK(smp_call_function_lock);
int __init __cpu_up(unsigned int cpu)
{
struct task_struct *idle;
pgd_t *pgd;
pmd_t *pmd;
int ret;
/*
* Spawn a new process manually. Grab a pointer to
* its task struct so we can mess with it
*/
idle = fork_idle(cpu);
if (IS_ERR(idle)) {
printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
return PTR_ERR(idle);
}
/*
* 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, PHYS_OFFSET);
*pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) |
PMD_TYPE_SECT | PMD_SECT_AP_WRITE);
/*
* We need to tell the secondary core where to find
* its stack and the page tables.
*/
secondary_data.stack = (void *)idle->thread_info + THREAD_SIZE - 8;
secondary_data.pgdir = virt_to_phys(pgd);
wmb();
/*
* 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 = 0;
secondary_data.pgdir = 0;
*pmd_offset(pgd, PHYS_OFFSET) = __pmd(0);
pgd_free(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;
}
/*
* This is the secondary CPU boot entry. We're using this CPUs
* idle thread stack, but a set of temporary page tables.
*/
asmlinkage void __init 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;
cpu_set(cpu, mm->cpu_vm_mask);
cpu_switch_mm(mm->pgd, mm);
enter_lazy_tlb(mm, current);
cpu_init();
/*
* Give the platform a chance to do its own initialisation.
*/
platform_secondary_init(cpu);
/*
* Enable local interrupts.
*/
local_irq_enable();
local_fiq_enable();
calibrate_delay();
smp_store_cpu_info(cpu);
/*
* OK, now it's safe to let the boot CPU continue
*/
cpu_set(cpu, cpu_online_map);
/*
* 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 __init 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();
cpu_set(cpu, cpu_present_mask);
cpu_set(cpu, cpu_online_map);
}
static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg)
{
unsigned long flags;
unsigned int cpu;
local_irq_save(flags);
for_each_cpu_mask(cpu, callmap) {
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(callmap);
local_irq_restore(flags);
}
/*
* You must not call this function with disabled interrupts, from a
* hardware interrupt handler, nor from a bottom half handler.
*/
int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry,
int wait, cpumask_t callmap)
{
struct smp_call_struct data;
unsigned long timeout;
int ret = 0;
data.func = func;
data.info = info;
data.wait = wait;
cpu_clear(smp_processor_id(), callmap);
if (cpus_empty(callmap))
goto out;
data.pending = callmap;
if (wait)
data.unfinished = callmap;
/*
* try to get the mutex on smp_call_function_data
*/
spin_lock(&smp_call_function_lock);
smp_call_function_data = &data;
send_ipi_message(callmap, IPI_CALL_FUNC);
timeout = jiffies + HZ;
while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
barrier();
/*
* did we time out?
*/
if (!cpus_empty(data.pending)) {
/*
* this may be causing our panic - report it
*/
printk(KERN_CRIT
"CPU%u: smp_call_function timeout for %p(%p)\n"
" callmap %lx pending %lx, %swait\n",
smp_processor_id(), func, info, callmap, data.pending,
wait ? "" : "no ");
/*
* TRACE
*/
timeout = jiffies + (5 * HZ);
while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
barrier();
if (cpus_empty(data.pending))
printk(KERN_CRIT " RESOLVED\n");
else
printk(KERN_CRIT " STILL STUCK\n");
}
/*
* whatever happened, we're done with the data, so release it
*/
smp_call_function_data = NULL;
spin_unlock(&smp_call_function_lock);
if (!cpus_empty(data.pending)) {
ret = -ETIMEDOUT;
goto out;
}
if (wait)
while (!cpus_empty(data.unfinished))
barrier();
out:
return 0;
}
int smp_call_function(void (*func)(void *info), void *info, int retry,
int wait)
{
return smp_call_function_on_cpu(func, info, retry, wait,
cpu_online_map);
}
void show_ipi_list(struct seq_file *p)
{
unsigned int cpu;
seq_puts(p, "IPI:");
for_each_online_cpu(cpu)
seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
seq_putc(p, '\n');
}
static void ipi_timer(struct pt_regs *regs)
{
int user = user_mode(regs);
irq_enter();
profile_tick(CPU_PROFILING, regs);
update_process_times(user);
irq_exit();
}
/*
* ipi_call_function - handle IPI from smp_call_function()
*
* Note that we copy data out of the cross-call structure and then
* let the caller know that we're here and have done with their data
*/
static void ipi_call_function(unsigned int cpu)
{
struct smp_call_struct *data = smp_call_function_data;
void (*func)(void *info) = data->func;
void *info = data->info;
int wait = data->wait;
cpu_clear(cpu, data->pending);
func(info);
if (wait)
cpu_clear(cpu, data->unfinished);
}
static DEFINE_SPINLOCK(stop_lock);
/*
* ipi_cpu_stop - handle IPI from smp_send_stop()
*/
static void ipi_cpu_stop(unsigned int cpu)
{
spin_lock(&stop_lock);
printk(KERN_CRIT "CPU%u: stopping\n", cpu);
dump_stack();
spin_unlock(&stop_lock);
cpu_clear(cpu, cpu_online_map);
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
*/
void do_IPI(struct pt_regs *regs)
{
unsigned int cpu = smp_processor_id();
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
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(regs);
break;
case IPI_RESCHEDULE:
/*
* nothing more to do - eveything is
* done on the interrupt return path
*/
break;
case IPI_CALL_FUNC:
ipi_call_function(cpu);
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);
}
}
void smp_send_reschedule(int cpu)
{
send_ipi_message(cpumask_of_cpu(cpu), IPI_RESCHEDULE);
}
void smp_send_timer(void)
{
cpumask_t mask = cpu_online_map;
cpu_clear(smp_processor_id(), mask);
send_ipi_message(mask, IPI_TIMER);
}
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 __init setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
