/*
** SMP Support
**
** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
**
** Lots of stuff stolen from arch/alpha/kernel/smp.c
** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
**
** Thanks to John Curry and Ullas Ponnadi. I learned alot from their work.
** -grant (1/12/2001)
**
** 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.
*/
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <asm/current.h>
#include <asm/delay.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
#include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
#include <asm/mmu_context.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/unistd.h>
#include <asm/cacheflush.h>
#undef DEBUG_SMP
#ifdef DEBUG_SMP
static int smp_debug_lvl = 0;
#define smp_debug(lvl, printargs...) \
if (lvl >= smp_debug_lvl) \
printk(printargs);
#else
#define smp_debug(lvl, ...)
#endif /* DEBUG_SMP */
DEFINE_SPINLOCK(smp_lock);
volatile struct task_struct *smp_init_current_idle_task;
static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */
static int parisc_max_cpus __read_mostly = 1;
/* online cpus are ones that we've managed to bring up completely
* possible cpus are all valid cpu
* present cpus are all detected cpu
*
* On startup we bring up the "possible" cpus. Since we discover
* CPUs later, we add them as hotplug, so the possible cpu mask is
* empty in the beginning.
*/
cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */
cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */
EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL(cpu_possible_map);
DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED;
struct smp_call_struct {
void (*func) (void *info);
void *info;
long wait;
atomic_t unstarted_count;
atomic_t unfinished_count;
};
static volatile struct smp_call_struct *smp_call_function_data;
enum ipi_message_type {
IPI_NOP=0,
IPI_RESCHEDULE=1,
IPI_CALL_FUNC,
IPI_CPU_START,
IPI_CPU_STOP,
IPI_CPU_TEST
};
/********** SMP inter processor interrupt and communication routines */
#undef PER_CPU_IRQ_REGION
#ifdef PER_CPU_IRQ_REGION
/* XXX REVISIT Ignore for now.
** *May* need this "hook" to register IPI handler
** once we have perCPU ExtIntr switch tables.
*/
static void
ipi_init(int cpuid)
{
#error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
if(cpu_online(cpuid) )
{
switch_to_idle_task(current);
}
return;
}
#endif
/*
** Yoink this CPU from the runnable list...
**
*/
static void
halt_processor(void)
{
/* REVISIT : redirect I/O Interrupts to another CPU? */
/* REVISIT : does PM *know* this CPU isn't available? */
cpu_clear(smp_processor_id(), cpu_online_map);
local_irq_disable();
for (;;)
;
}
irqreturn_t
ipi_interrupt(int irq, void *dev_id)
{
int this_cpu = smp_processor_id();
struct cpuinfo_parisc *p = &cpu_data[this_cpu];
unsigned long ops;
unsigned long flags;
/* Count this now; we may make a call that never returns. */
p->ipi_count++;
mb(); /* Order interrupt and bit testing. */
for (;;) {
spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
spin_lock_irqsave(lock, flags);
ops = p->pending_ipi;
p->pending_ipi = 0;
spin_unlock_irqrestore(lock, flags);
mb(); /* Order bit clearing and data access. */
if (!ops)
break;
while (ops) {
unsigned long which = ffz(~ops);
ops &= ~(1 << which);
switch (which) {
case IPI_NOP:
smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
break;
case IPI_RESCHEDULE:
smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
/*
* Reschedule callback. Everything to be
* done is done by the interrupt return path.
*/
break;
case IPI_CALL_FUNC:
smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
{
volatile struct smp_call_struct *data;
void (*func)(void *info);
void *info;
int wait;
data = smp_call_function_data;
func = data->func;
info = data->info;
wait = data->wait;
mb();
atomic_dec ((atomic_t *)&data->unstarted_count);
/* At this point, *data can't
* be relied upon.
*/
(*func)(info);
/* Notify the sending CPU that the
* task is done.
*/
mb();
if (wait)
atomic_dec ((atomic_t *)&data->unfinished_count);
}
break;
case IPI_CPU_START:
smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
break;
case IPI_CPU_STOP:
smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
halt_processor();
break;
case IPI_CPU_TEST:
smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
break;
default:
printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
this_cpu, which);
return IRQ_NONE;
} /* Switch */
/* let in any pending interrupts */
local_irq_enable();
local_irq_disable();
} /* while (ops) */
}
return IRQ_HANDLED;
}
static inline void
ipi_send(int cpu, enum ipi_message_type op)
{
struct cpuinfo_parisc *p = &cpu_data[cpu];
spinlock_t *lock = &per_cpu(ipi_lock, cpu);
unsigned long flags;
spin_lock_irqsave(lock, flags);
p->pending_ipi |= 1 << op;
gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa);
spin_unlock_irqrestore(lock, flags);
}
static inline void
send_IPI_single(int dest_cpu, enum ipi_message_type op)
{
if (dest_cpu == NO_PROC_ID) {
BUG();
return;
}
ipi_send(dest_cpu, op);
}
static inline void
send_IPI_allbutself(enum ipi_message_type op)
{
int i;
for_each_online_cpu(i) {
if (i != smp_processor_id())
send_IPI_single(i, op);
}
}
inline void
smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
static inline void
smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); }
void
smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
void
smp_send_all_nop(void)
{
send_IPI_allbutself(IPI_NOP);
}
/**
* 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.
* <retry> If true, keep retrying until ready.
* <wait> If true, wait 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 have executed.
*/
int
smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
{
struct smp_call_struct data;
unsigned long timeout;
static DEFINE_SPINLOCK(lock);
int retries = 0;
if (num_online_cpus() < 2)
return 0;
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
/* can also deadlock if IPIs are disabled */
WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0);
data.func = func;
data.info = info;
data.wait = wait;
atomic_set(&data.unstarted_count, num_online_cpus() - 1);
atomic_set(&data.unfinished_count, num_online_cpus() - 1);
if (retry) {
spin_lock (&lock);
while (smp_call_function_data != 0)
barrier();
}
else {
spin_lock (&lock);
if (smp_call_function_data) {
spin_unlock (&lock);
return -EBUSY;
}
}
smp_call_function_data = &data;
spin_unlock (&lock);
/* Send a message to all other CPUs and wait for them to respond */
send_IPI_allbutself(IPI_CALL_FUNC);
retry:
/* Wait for response */
timeout = jiffies + HZ;
while ( (atomic_read (&data.unstarted_count) > 0) &&
time_before (jiffies, timeout) )
barrier ();
if (atomic_read (&data.unstarted_count) > 0) {
printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n",
smp_processor_id(), ++retries);
goto retry;
}
/* We either got one or timed out. Release the lock */
mb();
smp_call_function_data = NULL;
while (wait && atomic_read (&data.unfinished_count) > 0)
barrier ();
return 0;
}
EXPORT_SYMBOL(smp_call_function);
/*
* Flush all other CPU's tlb and then mine. Do this with on_each_cpu()
* as we want to ensure all TLB's flushed before proceeding.
*/
void
smp_flush_tlb_all(void)
{
on_each_cpu(flush_tlb_all_local, NULL, 1, 1);
}
/*
* Called by secondaries to update state and initialize CPU registers.
*/
static void __init
smp_cpu_init(int cpunum)
{
extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */
extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
/* Set modes and Enable floating point coprocessor */
(void) init_per_cpu(cpunum);
disable_sr_hashing();
mb();
/* Well, support 2.4 linux scheme as well. */
if (cpu_test_and_set(cpunum, cpu_online_map))
{
extern void machine_halt(void); /* arch/parisc.../process.c */
printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
machine_halt();
}
/* Initialise the idle task for this CPU */
atomic_inc(&init_mm.mm_count);
current->active_mm = &init_mm;
if(current->mm)
BUG();
enter_lazy_tlb(&init_mm, current);
init_IRQ(); /* make sure no IRQ's are enabled or pending */
start_cpu_itimer();
}
/*
* Slaves start using C here. Indirectly called from smp_slave_stext.
* Do what start_kernel() and main() do for boot strap processor (aka monarch)
*/
void __init smp_callin(void)
{
int slave_id = cpu_now_booting;
#if 0
void *istack;
#endif
smp_cpu_init(slave_id);
preempt_disable();
#if 0 /* NOT WORKING YET - see entry.S */
istack = (void *)__get_free_pages(GFP_KERNEL,ISTACK_ORDER);
if (istack == NULL) {
printk(KERN_CRIT "Failed to allocate interrupt stack for cpu %d\n",slave_id);
BUG();
}
mtctl(istack,31);
#endif
flush_cache_all_local(); /* start with known state */
flush_tlb_all_local(NULL);
local_irq_enable(); /* Interrupts have been off until now */
cpu_idle(); /* Wait for timer to schedule some work */
/* NOTREACHED */
panic("smp_callin() AAAAaaaaahhhh....\n");
}
/*
* Bring one cpu online.
*/
int __init smp_boot_one_cpu(int cpuid)
{
struct task_struct *idle;
long timeout;
/*
* Create an idle task for this CPU. Note the address wed* give
* to kernel_thread is irrelevant -- it's going to start
* where OS_BOOT_RENDEVZ vector in SAL says to start. But
* this gets all the other task-y sort of data structures set
* up like we wish. We need to pull the just created idle task
* off the run queue and stuff it into the init_tasks[] array.
* Sheesh . . .
*/
idle = fork_idle(cpuid);
if (IS_ERR(idle))
panic("SMP: fork failed for CPU:%d", cpuid);
task_thread_info(idle)->cpu = cpuid;
/* Let _start know what logical CPU we're booting
** (offset into init_tasks[],cpu_data[])
*/
cpu_now_booting = cpuid;
/*
** boot strap code needs to know the task address since
** it also contains the process stack.
*/
smp_init_current_idle_task = idle ;
mb();
printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa);
/*
** This gets PDC to release the CPU from a very tight loop.
**
** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
** is executed after receiving the rendezvous signal (an interrupt to
** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
** contents of memory are valid."
*/
gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa);
mb();
/*
* OK, wait a bit for that CPU to finish staggering about.
* Slave will set a bit when it reaches smp_cpu_init().
* Once the "monarch CPU" sees the bit change, it can move on.
*/
for (timeout = 0; timeout < 10000; timeout++) {
if(cpu_online(cpuid)) {
/* Which implies Slave has started up */
cpu_now_booting = 0;
smp_init_current_idle_task = NULL;
goto alive ;
}
udelay(100);
barrier();
}
put_task_struct(idle);
idle = NULL;
printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
return -1;
alive:
/* Remember the Slave data */
smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
cpuid, timeout * 100);
return 0;
}
void __devinit smp_prepare_boot_cpu(void)
{
int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */
/* Setup BSP mappings */
printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor);
cpu_set(bootstrap_processor, cpu_online_map);
cpu_set(bootstrap_processor, cpu_present_map);
}
/*
** inventory.c:do_inventory() hasn't yet been run and thus we
** don't 'discover' the additional CPU's until later.
*/
void __init smp_prepare_cpus(unsigned int max_cpus)
{
cpus_clear(cpu_present_map);
cpu_set(0, cpu_present_map);
parisc_max_cpus = max_cpus;
if (!max_cpus)
printk(KERN_INFO "SMP mode deactivated.\n");
}
void smp_cpus_done(unsigned int cpu_max)
{
return;
}
int __cpuinit __cpu_up(unsigned int cpu)
{
if (cpu != 0 && cpu < parisc_max_cpus)
smp_boot_one_cpu(cpu);
return cpu_online(cpu) ? 0 : -ENOSYS;
}
#ifdef CONFIG_PROC_FS
int __init
setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
#endif
