/*
* SMP support for ppc.
*
* Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
* deal of code from the sparc and intel versions.
*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*
* PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
* Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#undef DEBUG
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/paca.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/system.h>
#include <asm/abs_addr.h>
#include "mpic.h"
#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
cpumask_t cpu_possible_map = CPU_MASK_NONE;
cpumask_t cpu_online_map = CPU_MASK_NONE;
cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE };
EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL(cpu_possible_map);
struct smp_ops_t *smp_ops;
static volatile unsigned int cpu_callin_map[NR_CPUS];
extern unsigned char stab_array[];
void smp_call_function_interrupt(void);
int smt_enabled_at_boot = 1;
#ifdef CONFIG_MPIC
void smp_mpic_message_pass(int target, int msg)
{
/* make sure we're sending something that translates to an IPI */
if ( msg > 0x3 ){
printk("SMP %d: smp_message_pass: unknown msg %d\n",
smp_processor_id(), msg);
return;
}
switch ( target )
{
case MSG_ALL:
mpic_send_ipi(msg, 0xffffffff);
break;
case MSG_ALL_BUT_SELF:
mpic_send_ipi(msg, 0xffffffff & ~(1 << smp_processor_id()));
break;
default:
mpic_send_ipi(msg, 1 << target);
break;
}
}
int __init smp_mpic_probe(void)
{
int nr_cpus;
DBG("smp_mpic_probe()...\n");
nr_cpus = cpus_weight(cpu_possible_map);
DBG("nr_cpus: %d\n", nr_cpus);
if (nr_cpus > 1)
mpic_request_ipis();
return nr_cpus;
}
void __devinit smp_mpic_setup_cpu(int cpu)
{
mpic_setup_this_cpu();
}
void __devinit smp_generic_kick_cpu(int nr)
{
BUG_ON(nr < 0 || nr >= NR_CPUS);
/*
* The processor is currently spinning, waiting for the
* cpu_start field to become non-zero After we set cpu_start,
* the processor will continue on to secondary_start
*/
paca[nr].cpu_start = 1;
smp_mb();
}
#endif /* CONFIG_MPIC */
static void __init smp_space_timers(unsigned int max_cpus)
{
int i;
unsigned long offset = tb_ticks_per_jiffy / max_cpus;
unsigned long previous_tb = paca[boot_cpuid].next_jiffy_update_tb;
for_each_cpu(i) {
if (i != boot_cpuid) {
paca[i].next_jiffy_update_tb =
previous_tb + offset;
previous_tb = paca[i].next_jiffy_update_tb;
}
}
}
void smp_message_recv(int msg, struct pt_regs *regs)
{
switch(msg) {
case PPC_MSG_CALL_FUNCTION:
smp_call_function_interrupt();
break;
case PPC_MSG_RESCHEDULE:
/* XXX Do we have to do this? */
set_need_resched();
break;
#if 0
case PPC_MSG_MIGRATE_TASK:
/* spare */
break;
#endif
#ifdef CONFIG_DEBUGGER
case PPC_MSG_DEBUGGER_BREAK:
debugger_ipi(regs);
break;
#endif
default:
printk("SMP %d: smp_message_recv(): unknown msg %d\n",
smp_processor_id(), msg);
break;
}
}
void smp_send_reschedule(int cpu)
{
smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
}
#ifdef CONFIG_DEBUGGER
void smp_send_debugger_break(int cpu)
{
smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
}
#endif
static void stop_this_cpu(void *dummy)
{
local_irq_disable();
while (1)
;
}
void smp_send_stop(void)
{
smp_call_function(stop_this_cpu, NULL, 1, 0);
}
/*
* Structure and data for smp_call_function(). This is designed to minimise
* static memory requirements. It also looks cleaner.
* Stolen from the i386 version.
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);
static struct call_data_struct {
void (*func) (void *info);
void *info;
atomic_t started;
atomic_t finished;
int wait;
} *call_data;
/* delay of at least 8 seconds on 1GHz cpu */
#define SMP_CALL_TIMEOUT (1UL << (30 + 3))
/*
* This function sends a 'generic call function' IPI to all other CPUs
* in the system.
*
* [SUMMARY] Run a function on all other CPUs.
* <func> The function to run. This must be fast and non-blocking.
* <info> An arbitrary pointer to pass to the function.
* <nonatomic> currently unused.
* <wait> If true, wait (atomically) until function has completed on other CPUs.
* [RETURNS] 0 on success, else a negative status code. Does not return until
* remote CPUs are nearly ready to execute <<func>> or are or have executed.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler.
*/
int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
int wait)
{
struct call_data_struct data;
int ret = -1, cpus;
unsigned long timeout;
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
data.func = func;
data.info = info;
atomic_set(&data.started, 0);
data.wait = wait;
if (wait)
atomic_set(&data.finished, 0);
spin_lock(&call_lock);
/* Must grab online cpu count with preempt disabled, otherwise
* it can change. */
cpus = num_online_cpus() - 1;
if (!cpus) {
ret = 0;
goto out;
}
call_data = &data;
smp_wmb();
/* Send a message to all other CPUs and wait for them to respond */
smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_CALL_FUNCTION);
/* Wait for response */
timeout = SMP_CALL_TIMEOUT;
while (atomic_read(&data.started) != cpus) {
HMT_low();
if (--timeout == 0) {
printk("smp_call_function on cpu %d: other cpus not "
"responding (%d)\n", smp_processor_id(),
atomic_read(&data.started));
debugger(NULL);
goto out;
}
}
if (wait) {
timeout = SMP_CALL_TIMEOUT;
while (atomic_read(&data.finished) != cpus) {
HMT_low();
if (--timeout == 0) {
printk("smp_call_function on cpu %d: other "
"cpus not finishing (%d/%d)\n",
smp_processor_id(),
atomic_read(&data.finished),
atomic_read(&data.started));
debugger(NULL);
goto out;
}
}
}
ret = 0;
out:
call_data = NULL;
HMT_medium();
spin_unlock(&call_lock);
return ret;
}
EXPORT_SYMBOL(smp_call_function);
void smp_call_function_interrupt(void)
{
void (*func) (void *info);
void *info;
int wait;
/* call_data will be NULL if the sender timed out while
* waiting on us to receive the call.
*/
if (!call_data)
return;
func = call_data->func;
info = call_data->info;
wait = call_data->wait;
if (!wait)
smp_mb__before_atomic_inc();
/*
* Notify initiating CPU that I've grabbed the data and am
* about to execute the function
*/
atomic_inc(&call_data->started);
/*
* At this point the info structure may be out of scope unless wait==1
*/
(*func)(info);
if (wait) {
smp_mb__before_atomic_inc();
atomic_inc(&call_data->finished);
}
}
extern struct gettimeofday_struct do_gtod;
struct thread_info *current_set[NR_CPUS];
DECLARE_PER_CPU(unsigned int, pvr);
static void __devinit smp_store_cpu_info(int id)
{
per_cpu(pvr, id) = mfspr(SPRN_PVR);
}
static void __init smp_create_idle(unsigned int cpu)
{
struct task_struct *p;
/* create a process for the processor */
p = fork_idle(cpu);
if (IS_ERR(p))
panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
paca[cpu].__current = p;
current_set[cpu] = p->thread_info;
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int cpu;
DBG("smp_prepare_cpus\n");
/*
* setup_cpu may need to be called on the boot cpu. We havent
* spun any cpus up but lets be paranoid.
*/
BUG_ON(boot_cpuid != smp_processor_id());
/* Fixup boot cpu */
smp_store_cpu_info(boot_cpuid);
cpu_callin_map[boot_cpuid] = 1;
#ifndef CONFIG_PPC_ISERIES
paca[boot_cpuid].next_jiffy_update_tb = tb_last_stamp = get_tb();
/*
* Should update do_gtod.stamp_xsec.
* For now we leave it which means the time can be some
* number of msecs off until someone does a settimeofday()
*/
do_gtod.varp->tb_orig_stamp = tb_last_stamp;
systemcfg->tb_orig_stamp = tb_last_stamp;
#endif
max_cpus = smp_ops->probe();
smp_space_timers(max_cpus);
for_each_cpu(cpu)
if (cpu != boot_cpuid)
smp_create_idle(cpu);
}
void __devinit smp_prepare_boot_cpu(void)
{
BUG_ON(smp_processor_id() != boot_cpuid);
cpu_set(boot_cpuid, cpu_online_map);
paca[boot_cpuid].__current = current;
current_set[boot_cpuid] = current->thread_info;
}
#ifdef CONFIG_HOTPLUG_CPU
/* State of each CPU during hotplug phases */
DEFINE_PER_CPU(int, cpu_state) = { 0 };
int generic_cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
if (cpu == boot_cpuid)
return -EBUSY;
systemcfg->processorCount--;
cpu_clear(cpu, cpu_online_map);
fixup_irqs(cpu_online_map);
return 0;
}
int generic_cpu_enable(unsigned int cpu)
{
/* Do the normal bootup if we haven't
* already bootstrapped. */
if (system_state != SYSTEM_RUNNING)
return -ENOSYS;
/* get the target out of it's holding state */
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
smp_wmb();
while (!cpu_online(cpu))
cpu_relax();
fixup_irqs(cpu_online_map);
/* counter the irq disable in fixup_irqs */
local_irq_enable();
return 0;
}
void generic_cpu_die(unsigned int cpu)
{
int i;
for (i = 0; i < 100; i++) {
smp_rmb();
if (per_cpu(cpu_state, cpu) == CPU_DEAD)
return;
msleep(100);
}
printk(KERN_ERR "CPU%d didn't die...\n", cpu);
}
void generic_mach_cpu_die(void)
{
unsigned int cpu;
local_irq_disable();
cpu = smp_processor_id();
printk(KERN_DEBUG "CPU%d offline\n", cpu);
__get_cpu_var(cpu_state) = CPU_DEAD;
smp_wmb();
while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
cpu_relax();
flush_tlb_pending();
cpu_set(cpu, cpu_online_map);
local_irq_enable();
}
#endif
static int __devinit cpu_enable(unsigned int cpu)
{
if (smp_ops->cpu_enable)
return smp_ops->cpu_enable(cpu);
return -ENOSYS;
}
int __devinit __cpu_up(unsigned int cpu)
{
int c;
if (!cpu_enable(cpu))
return 0;
if (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))
return -EINVAL;
paca[cpu].default_decr = tb_ticks_per_jiffy;
if (!cpu_has_feature(CPU_FTR_SLB)) {
void *tmp;
/* maximum of 48 CPUs on machines with a segment table */
if (cpu >= 48)
BUG();
tmp = &stab_array[PAGE_SIZE * cpu];
memset(tmp, 0, PAGE_SIZE);
paca[cpu].stab_addr = (unsigned long)tmp;
paca[cpu].stab_real = virt_to_abs(tmp);
}
/* Make sure callin-map entry is 0 (can be leftover a CPU
* hotplug
*/
cpu_callin_map[cpu] = 0;
/* The information for processor bringup must
* be written out to main store before we release
* the processor.
*/
smp_mb();
/* wake up cpus */
DBG("smp: kicking cpu %d\n", cpu);
smp_ops->kick_cpu(cpu);
/*
* wait to see if the cpu made a callin (is actually up).
* use this value that I found through experimentation.
* -- Cort
*/
if (system_state < SYSTEM_RUNNING)
for (c = 5000; c && !cpu_callin_map[cpu]; c--)
udelay(100);
#ifdef CONFIG_HOTPLUG_CPU
else
/*
* CPUs can take much longer to come up in the
* hotplug case. Wait five seconds.
*/
for (c = 25; c && !cpu_callin_map[cpu]; c--) {
msleep(200);
}
#endif
if (!cpu_callin_map[cpu]) {
printk("Processor %u is stuck.\n", cpu);
return -ENOENT;
}
printk("Processor %u found.\n", cpu);
if (smp_ops->give_timebase)
smp_ops->give_timebase();
/* Wait until cpu puts itself in the online map */
while (!cpu_online(cpu))
cpu_relax();
return 0;
}
/* Activate a secondary processor. */
int __devinit start_secondary(void *unused)
{
unsigned int cpu = smp_processor_id();
atomic_inc(&init_mm.mm_count);
current->active_mm = &init_mm;
smp_store_cpu_info(cpu);
set_dec(paca[cpu].default_decr);
cpu_callin_map[cpu] = 1;
smp_ops->setup_cpu(cpu);
if (smp_ops->take_timebase)
smp_ops->take_timebase();
spin_lock(&call_lock);
cpu_set(cpu, cpu_online_map);
spin_unlock(&call_lock);
local_irq_enable();
cpu_idle();
return 0;
}
int setup_profiling_timer(unsigned int multiplier)
{
return 0;
}
void __init smp_cpus_done(unsigned int max_cpus)
{
cpumask_t old_mask;
/* We want the setup_cpu() here to be called from CPU 0, but our
* init thread may have been "borrowed" by another CPU in the meantime
* se we pin us down to CPU 0 for a short while
*/
old_mask = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
smp_ops->setup_cpu(boot_cpuid);
set_cpus_allowed(current, old_mask);
}
#ifdef CONFIG_HOTPLUG_CPU
int __cpu_disable(void)
{
if (smp_ops->cpu_disable)
return smp_ops->cpu_disable();
return -ENOSYS;
}
void __cpu_die(unsigned int cpu)
{
if (smp_ops->cpu_die)
smp_ops->cpu_die(cpu);
}
#endif
