// SPDX-License-Identifier: GPL-2.0-or-later
/*
** SMP Support
**
** Copyright (C) 1999 Walt Drummond <[email protected]>
** Copyright (C) 1999 David Mosberger-Tang <[email protected]>
** Copyright (C) 2001,2004 Grant Grundler <[email protected]>
**
** 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 a lot from their work.
** -grant (1/12/2001)
**
*/
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched/mm.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/kgdb.h>
#include <linux/sched/hotplug.h>
#include <linux/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/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, ...) do { } while(0)
#endif /* DEBUG_SMP */
volatile struct task_struct *smp_init_current_idle_task;
/* track which CPU is booting */
static volatile int cpu_now_booting;
static DEFINE_PER_CPU(spinlock_t, ipi_lock);
enum ipi_message_type {
IPI_NOP=0,
IPI_RESCHEDULE=1,
IPI_CALL_FUNC,
IPI_CPU_START,
IPI_CPU_STOP,
IPI_CPU_TEST,
#ifdef CONFIG_KGDB
IPI_ENTER_KGDB,
#endif
};
/********** 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? */
set_cpu_online(smp_processor_id(), false);
local_irq_disable();
__pdc_cpu_rendezvous();
for (;;)
;
}
irqreturn_t __irq_entry
ipi_interrupt(int irq, void *dev_id)
{
int this_cpu = smp_processor_id();
struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
unsigned long ops;
unsigned long flags;
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);
inc_irq_stat(irq_resched_count);
scheduler_ipi();
break;
case IPI_CALL_FUNC:
smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
inc_irq_stat(irq_call_count);
generic_smp_call_function_interrupt();
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;
#ifdef CONFIG_KGDB
case IPI_ENTER_KGDB:
smp_debug(100, KERN_DEBUG "CPU%d ENTER_KGDB\n", this_cpu);
kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
break;
#endif
default:
printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
this_cpu, which);
return IRQ_NONE;
} /* Switch */
/* before doing more, let in any pending interrupts */
if (ops) {
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 = &per_cpu(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, p->hpa);
spin_unlock_irqrestore(lock, flags);
}
static void
send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
{
int cpu;
for_each_cpu(cpu, mask)
ipi_send(cpu, op);
}
static inline void
send_IPI_single(int dest_cpu, enum ipi_message_type op)
{
BUG_ON(dest_cpu == NO_PROC_ID);
ipi_send(dest_cpu, op);
}
static inline void
send_IPI_allbutself(enum ipi_message_type op)
{
int i;
preempt_disable();
for_each_online_cpu(i) {
if (i != smp_processor_id())
send_IPI_single(i, op);
}
preempt_enable();
}
#ifdef CONFIG_KGDB
void kgdb_roundup_cpus(void)
{
send_IPI_allbutself(IPI_ENTER_KGDB);
}
#endif
inline void
smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
void
arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
void
smp_send_all_nop(void)
{
send_IPI_allbutself(IPI_NOP);
}
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
send_IPI_mask(mask, IPI_CALL_FUNC);
}
void arch_send_call_function_single_ipi(int cpu)
{
send_IPI_single(cpu, IPI_CALL_FUNC);
}
/*
* Called by secondaries to update state and initialize CPU registers.
*/
static void
smp_cpu_init(int cpunum)
{
/* Set modes and Enable floating point coprocessor */
init_per_cpu(cpunum);
disable_sr_hashing();
mb();
/* Well, support 2.4 linux scheme as well. */
if (cpu_online(cpunum)) {
extern void machine_halt(void); /* arch/parisc.../process.c */
printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
machine_halt();
}
notify_cpu_starting(cpunum);
set_cpu_online(cpunum, true);
/* Initialise the idle task for this CPU */
mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
init_IRQ(); /* make sure no IRQs 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 smp_callin(unsigned long pdce_proc)
{
int slave_id = cpu_now_booting;
#ifdef CONFIG_64BIT
WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
| PAGE0->mem_pdc) != pdce_proc);
#endif
smp_cpu_init(slave_id);
flush_cache_all_local(); /* start with known state */
flush_tlb_all_local(NULL);
local_irq_enable(); /* Interrupts have been off until now */
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
/* NOTREACHED */
panic("smp_callin() AAAAaaaaahhhh....\n");
}
/*
* Bring one cpu online.
*/
static int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
{
const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
long timeout;
#ifdef CONFIG_HOTPLUG_CPU
int i;
/* reset irq statistics for this CPU */
memset(&per_cpu(irq_stat, cpuid), 0, sizeof(irq_cpustat_t));
for (i = 0; i < NR_IRQS; i++) {
struct irq_desc *desc = irq_to_desc(i);
if (desc && desc->kstat_irqs)
*per_cpu_ptr(desc->kstat_irqs, cpuid) = (struct irqstat) { };
}
#endif
/* wait until last booting CPU has started. */
while (cpu_now_booting)
;
/* 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(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->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, p->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;
goto alive ;
}
udelay(100);
barrier();
}
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 __init smp_prepare_boot_cpu(void)
{
pr_info("SMP: bootstrap CPU ID is 0\n");
}
/*
** inventory.c:do_inventory() hasn't yet been run and thus we
** don't 'discover' the additional CPUs until later.
*/
void __init smp_prepare_cpus(unsigned int max_cpus)
{
int cpu;
for_each_possible_cpu(cpu)
spin_lock_init(&per_cpu(ipi_lock, cpu));
init_cpu_present(cpumask_of(0));
}
void __init smp_cpus_done(unsigned int cpu_max)
{
}
int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
if (cpu_online(cpu))
return 0;
if (num_online_cpus() < nr_cpu_ids &&
num_online_cpus() < setup_max_cpus &&
smp_boot_one_cpu(cpu, tidle))
return -EIO;
return cpu_online(cpu) ? 0 : -EIO;
}
/*
* __cpu_disable runs on the processor to be shutdown.
*/
int __cpu_disable(void)
{
#ifdef CONFIG_HOTPLUG_CPU
unsigned int cpu = smp_processor_id();
remove_cpu_topology(cpu);
/*
* 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);
/* Find a new timesync master */
if (cpu == time_keeper_id) {
time_keeper_id = cpumask_first(cpu_online_mask);
pr_info("CPU %d is now promoted to time-keeper master\n", time_keeper_id);
}
disable_percpu_irq(IPI_IRQ);
irq_migrate_all_off_this_cpu();
flush_cache_all_local();
flush_tlb_all_local(NULL);
/* disable all irqs, including timer irq */
local_irq_disable();
/* wait for next timer irq ... */
mdelay(1000/HZ+100);
/* ... and then clear all pending external irqs */
set_eiem(0);
mtctl(~0UL, CR_EIRR);
mfctl(CR_EIRR);
mtctl(0, CR_EIRR);
#endif
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)
{
pdc_cpu_rendezvous_lock();
}
void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
{
pr_info("CPU%u: is shutting down\n", cpu);
/* set task's state to interruptible sleep */
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout((IS_ENABLED(CONFIG_64BIT) ? 8:2) * HZ);
pdc_cpu_rendezvous_unlock();
}
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