1 // SPDX-License-Identifier: GPL-2.0-or-later
5 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
6 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
7 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
9 ** Lots of stuff stolen from arch/alpha/kernel/smp.c
10 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
12 ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
16 #include <linux/types.h>
17 #include <linux/spinlock.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/sched/mm.h>
22 #include <linux/init.h>
23 #include <linux/interrupt.h>
24 #include <linux/smp.h>
25 #include <linux/kernel_stat.h>
27 #include <linux/err.h>
28 #include <linux/delay.h>
29 #include <linux/bitops.h>
30 #include <linux/ftrace.h>
31 #include <linux/cpu.h>
33 #include <linux/atomic.h>
34 #include <asm/current.h>
35 #include <asm/delay.h>
36 #include <asm/tlbflush.h>
39 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
40 #include <asm/mmu_context.h>
42 #include <asm/pgtable.h>
43 #include <asm/pgalloc.h>
44 #include <asm/processor.h>
45 #include <asm/ptrace.h>
46 #include <asm/unistd.h>
47 #include <asm/cacheflush.h>
51 static int smp_debug_lvl = 0;
52 #define smp_debug(lvl, printargs...) \
53 if (lvl >= smp_debug_lvl) \
56 #define smp_debug(lvl, ...) do { } while(0)
57 #endif /* DEBUG_SMP */
59 volatile struct task_struct *smp_init_current_idle_task;
61 /* track which CPU is booting */
62 static volatile int cpu_now_booting;
64 static int parisc_max_cpus = 1;
66 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
68 enum ipi_message_type {
78 /********** SMP inter processor interrupt and communication routines */
80 #undef PER_CPU_IRQ_REGION
81 #ifdef PER_CPU_IRQ_REGION
82 /* XXX REVISIT Ignore for now.
83 ** *May* need this "hook" to register IPI handler
84 ** once we have perCPU ExtIntr switch tables.
89 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
91 if(cpu_online(cpuid) )
93 switch_to_idle_task(current);
102 ** Yoink this CPU from the runnable list...
108 /* REVISIT : redirect I/O Interrupts to another CPU? */
109 /* REVISIT : does PM *know* this CPU isn't available? */
110 set_cpu_online(smp_processor_id(), false);
117 irqreturn_t __irq_entry
118 ipi_interrupt(int irq, void *dev_id)
120 int this_cpu = smp_processor_id();
121 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
126 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
127 spin_lock_irqsave(lock, flags);
128 ops = p->pending_ipi;
130 spin_unlock_irqrestore(lock, flags);
132 mb(); /* Order bit clearing and data access. */
138 unsigned long which = ffz(~ops);
140 ops &= ~(1 << which);
144 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
148 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
149 inc_irq_stat(irq_resched_count);
154 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
155 inc_irq_stat(irq_call_count);
156 generic_smp_call_function_interrupt();
160 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
164 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
169 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
173 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
177 /* let in any pending interrupts */
187 ipi_send(int cpu, enum ipi_message_type op)
189 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
190 spinlock_t *lock = &per_cpu(ipi_lock, cpu);
193 spin_lock_irqsave(lock, flags);
194 p->pending_ipi |= 1 << op;
195 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
196 spin_unlock_irqrestore(lock, flags);
200 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
204 for_each_cpu(cpu, mask)
209 send_IPI_single(int dest_cpu, enum ipi_message_type op)
211 BUG_ON(dest_cpu == NO_PROC_ID);
213 ipi_send(dest_cpu, op);
217 send_IPI_allbutself(enum ipi_message_type op)
221 for_each_online_cpu(i) {
222 if (i != smp_processor_id())
223 send_IPI_single(i, op);
229 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
232 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
235 smp_send_all_nop(void)
237 send_IPI_allbutself(IPI_NOP);
240 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
242 send_IPI_mask(mask, IPI_CALL_FUNC);
245 void arch_send_call_function_single_ipi(int cpu)
247 send_IPI_single(cpu, IPI_CALL_FUNC);
251 * Called by secondaries to update state and initialize CPU registers.
254 smp_cpu_init(int cpunum)
256 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
257 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
259 /* Set modes and Enable floating point coprocessor */
260 init_per_cpu(cpunum);
262 disable_sr_hashing();
266 /* Well, support 2.4 linux scheme as well. */
267 if (cpu_online(cpunum)) {
268 extern void machine_halt(void); /* arch/parisc.../process.c */
270 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
274 notify_cpu_starting(cpunum);
276 set_cpu_online(cpunum, true);
278 /* Initialise the idle task for this CPU */
280 current->active_mm = &init_mm;
282 enter_lazy_tlb(&init_mm, current);
284 init_IRQ(); /* make sure no IRQs are enabled or pending */
290 * Slaves start using C here. Indirectly called from smp_slave_stext.
291 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
293 void __init smp_callin(unsigned long pdce_proc)
295 int slave_id = cpu_now_booting;
298 WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
299 | PAGE0->mem_pdc) != pdce_proc);
302 smp_cpu_init(slave_id);
305 flush_cache_all_local(); /* start with known state */
306 flush_tlb_all_local(NULL);
308 local_irq_enable(); /* Interrupts have been off until now */
310 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
313 panic("smp_callin() AAAAaaaaahhhh....\n");
317 * Bring one cpu online.
319 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
321 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
324 task_thread_info(idle)->cpu = cpuid;
326 /* Let _start know what logical CPU we're booting
327 ** (offset into init_tasks[],cpu_data[])
329 cpu_now_booting = cpuid;
332 ** boot strap code needs to know the task address since
333 ** it also contains the process stack.
335 smp_init_current_idle_task = idle ;
338 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
341 ** This gets PDC to release the CPU from a very tight loop.
343 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
344 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
345 ** is executed after receiving the rendezvous signal (an interrupt to
346 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
347 ** contents of memory are valid."
349 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
353 * OK, wait a bit for that CPU to finish staggering about.
354 * Slave will set a bit when it reaches smp_cpu_init().
355 * Once the "monarch CPU" sees the bit change, it can move on.
357 for (timeout = 0; timeout < 10000; timeout++) {
358 if(cpu_online(cpuid)) {
359 /* Which implies Slave has started up */
361 smp_init_current_idle_task = NULL;
367 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
371 /* Remember the Slave data */
372 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
373 cpuid, timeout * 100);
377 void __init smp_prepare_boot_cpu(void)
379 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
381 /* Setup BSP mappings */
382 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
384 set_cpu_online(bootstrap_processor, true);
385 set_cpu_present(bootstrap_processor, true);
391 ** inventory.c:do_inventory() hasn't yet been run and thus we
392 ** don't 'discover' the additional CPUs until later.
394 void __init smp_prepare_cpus(unsigned int max_cpus)
398 for_each_possible_cpu(cpu)
399 spin_lock_init(&per_cpu(ipi_lock, cpu));
401 init_cpu_present(cpumask_of(0));
403 parisc_max_cpus = max_cpus;
405 printk(KERN_INFO "SMP mode deactivated.\n");
409 void smp_cpus_done(unsigned int cpu_max)
415 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
417 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
420 return cpu_online(cpu) ? 0 : -ENOSYS;
423 #ifdef CONFIG_PROC_FS
424 int setup_profiling_timer(unsigned int multiplier)