arch/parisc/kernel/smp.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3 ** SMP Support
   4 **
   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>
   8 **
   9 ** Lots of stuff stolen from arch/alpha/kernel/smp.c
  10 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
  11 **
  12 ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
  13 ** -grant (1/12/2001)
  14 **
  15 */
  16 #include <linux/types.h>
  17 #include <linux/spinlock.h>
  18
  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>
  26 #include <linux/mm.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>
  32
  33 #include <linux/atomic.h>
  34 #include <asm/current.h>
  35 #include <asm/delay.h>
  36 #include <asm/tlbflush.h>
  37
  38 #include <asm/io.h>
  39 #include <asm/irq.h>            /* for CPU_IRQ_REGION and friends */
  40 #include <asm/mmu_context.h>
  41 #include <asm/page.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>
  48
  49 #undef DEBUG_SMP
  50 #ifdef DEBUG_SMP
  51 static int smp_debug_lvl = 0;
  52 #define smp_debug(lvl, printargs...)            \
  53                 if (lvl >= smp_debug_lvl)       \
  54                         printk(printargs);
  55 #else
  56 #define smp_debug(lvl, ...)     do { } while(0)
  57 #endif /* DEBUG_SMP */
  58
  59 volatile struct task_struct *smp_init_current_idle_task;
  60
  61 /* track which CPU is booting */
  62 static volatile int cpu_now_booting;
  63
  64 static int parisc_max_cpus = 1;
  65
  66 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
  67
  68 enum ipi_message_type {
  69         IPI_NOP=0,
  70         IPI_RESCHEDULE=1,
  71         IPI_CALL_FUNC,
  72         IPI_CPU_START,
  73         IPI_CPU_STOP,
  74         IPI_CPU_TEST
  75 };
  76
  77
  78 /********** SMP inter processor interrupt and communication routines */
  79
  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.
  85 */
  86 static void
  87 ipi_init(int cpuid)
  88 {
  89 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
  90
  91         if(cpu_online(cpuid) )
  92         {
  93                 switch_to_idle_task(current);
  94         }
  95
  96         return;
  97 }
  98 #endif
  99
 100
 101 /*
 102 ** Yoink this CPU from the runnable list...
 103 **
 104 */
 105 static void
 106 halt_processor(void)
 107 {
 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);
 111         local_irq_disable();
 112         __pdc_cpu_rendezvous();
 113         for (;;)
 114                 ;
 115 }
 116
 117
 118 irqreturn_t __irq_entry
 119 ipi_interrupt(int irq, void *dev_id)
 120 {
 121         int this_cpu = smp_processor_id();
 122         struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
 123         unsigned long ops;
 124         unsigned long flags;
 125
 126         for (;;) {
 127                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 128                 spin_lock_irqsave(lock, flags);
 129                 ops = p->pending_ipi;
 130                 p->pending_ipi = 0;
 131                 spin_unlock_irqrestore(lock, flags);
 132
 133                 mb(); /* Order bit clearing and data access. */
 134
 135                 if (!ops)
 136                     break;
 137
 138                 while (ops) {
 139                         unsigned long which = ffz(~ops);
 140
 141                         ops &= ~(1 << which);
 142
 143                         switch (which) {
 144                         case IPI_NOP:
 145                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 146                                 break;
 147
 148                         case IPI_RESCHEDULE:
 149                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 150                                 inc_irq_stat(irq_resched_count);
 151                                 scheduler_ipi();
 152                                 break;
 153
 154                         case IPI_CALL_FUNC:
 155                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 156                                 inc_irq_stat(irq_call_count);
 157                                 generic_smp_call_function_interrupt();
 158                                 break;
 159
 160                         case IPI_CPU_START:
 161                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 162                                 break;
 163
 164                         case IPI_CPU_STOP:
 165                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 166                                 halt_processor();
 167                                 break;
 168
 169                         case IPI_CPU_TEST:
 170                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 171                                 break;
 172
 173                         default:
 174                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 175                                         this_cpu, which);
 176                                 return IRQ_NONE;
 177                         } /* Switch */
 178                 /* let in any pending interrupts */
 179                 local_irq_enable();
 180                 local_irq_disable();
 181                 } /* while (ops) */
 182         }
 183         return IRQ_HANDLED;
 184 }
 185
 186
 187 static inline void
 188 ipi_send(int cpu, enum ipi_message_type op)
 189 {
 190         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 191         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 192         unsigned long flags;
 193
 194         spin_lock_irqsave(lock, flags);
 195         p->pending_ipi |= 1 << op;
 196         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 197         spin_unlock_irqrestore(lock, flags);
 198 }
 199
 200 static void
 201 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
 202 {
 203         int cpu;
 204
 205         for_each_cpu(cpu, mask)
 206                 ipi_send(cpu, op);
 207 }
 208
 209 static inline void
 210 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 211 {
 212         BUG_ON(dest_cpu == NO_PROC_ID);
 213
 214         ipi_send(dest_cpu, op);
 215 }
 216
 217 static inline void
 218 send_IPI_allbutself(enum ipi_message_type op)
 219 {
 220         int i;
 221
 222         for_each_online_cpu(i) {
 223                 if (i != smp_processor_id())
 224                         send_IPI_single(i, op);
 225         }
 226 }
 227
 228
 229 inline void
 230 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 231
 232 void
 233 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 234
 235 void
 236 smp_send_all_nop(void)
 237 {
 238         send_IPI_allbutself(IPI_NOP);
 239 }
 240
 241 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 242 {
 243         send_IPI_mask(mask, IPI_CALL_FUNC);
 244 }
 245
 246 void arch_send_call_function_single_ipi(int cpu)
 247 {
 248         send_IPI_single(cpu, IPI_CALL_FUNC);
 249 }
 250
 251 /*
 252  * Called by secondaries to update state and initialize CPU registers.
 253  */
 254 static void __init
 255 smp_cpu_init(int cpunum)
 256 {
 257         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 258         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 259
 260         /* Set modes and Enable floating point coprocessor */
 261         init_per_cpu(cpunum);
 262
 263         disable_sr_hashing();
 264
 265         mb();
 266
 267         /* Well, support 2.4 linux scheme as well. */
 268         if (cpu_online(cpunum)) {
 269                 extern void machine_halt(void); /* arch/parisc.../process.c */
 270
 271                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 272                 machine_halt();
 273         }
 274
 275         notify_cpu_starting(cpunum);
 276
 277         set_cpu_online(cpunum, true);
 278
 279         /* Initialise the idle task for this CPU */
 280         mmgrab(&init_mm);
 281         current->active_mm = &init_mm;
 282         BUG_ON(current->mm);
 283         enter_lazy_tlb(&init_mm, current);
 284
 285         init_IRQ();   /* make sure no IRQs are enabled or pending */
 286         start_cpu_itimer();
 287 }
 288
 289
 290 /*
 291  * Slaves start using C here. Indirectly called from smp_slave_stext.
 292  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 293  */
 294 void __init smp_callin(unsigned long pdce_proc)
 295 {
 296         int slave_id = cpu_now_booting;
 297
 298 #ifdef CONFIG_64BIT
 299         WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
 300                         | PAGE0->mem_pdc) != pdce_proc);
 301 #endif
 302
 303         smp_cpu_init(slave_id);
 304         preempt_disable();
 305
 306         flush_cache_all_local(); /* start with known state */
 307         flush_tlb_all_local(NULL);
 308
 309         local_irq_enable();  /* Interrupts have been off until now */
 310
 311         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 312
 313         /* NOTREACHED */
 314         panic("smp_callin() AAAAaaaaahhhh....\n");
 315 }
 316
 317 /*
 318  * Bring one cpu online.
 319  */
 320 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 321 {
 322         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 323         long timeout;
 324
 325         task_thread_info(idle)->cpu = cpuid;
 326
 327         /* Let _start know what logical CPU we're booting
 328         ** (offset into init_tasks[],cpu_data[])
 329         */
 330         cpu_now_booting = cpuid;
 331
 332         /*
 333         ** boot strap code needs to know the task address since
 334         ** it also contains the process stack.
 335         */
 336         smp_init_current_idle_task = idle ;
 337         mb();
 338
 339         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
 340
 341         /*
 342         ** This gets PDC to release the CPU from a very tight loop.
 343         **
 344         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 345         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 346         ** is executed after receiving the rendezvous signal (an interrupt to
 347         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 348         ** contents of memory are valid."
 349         */
 350         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
 351         mb();
 352
 353         /*
 354          * OK, wait a bit for that CPU to finish staggering about.
 355          * Slave will set a bit when it reaches smp_cpu_init().
 356          * Once the "monarch CPU" sees the bit change, it can move on.
 357          */
 358         for (timeout = 0; timeout < 10000; timeout++) {
 359                 if(cpu_online(cpuid)) {
 360                         /* Which implies Slave has started up */
 361                         cpu_now_booting = 0;
 362                         smp_init_current_idle_task = NULL;
 363                         goto alive ;
 364                 }
 365                 udelay(100);
 366                 barrier();
 367         }
 368         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 369         return -1;
 370
 371 alive:
 372         /* Remember the Slave data */
 373         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 374                 cpuid, timeout * 100);
 375         return 0;
 376 }
 377
 378 void __init smp_prepare_boot_cpu(void)
 379 {
 380         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 381
 382         /* Setup BSP mappings */
 383         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 384
 385         set_cpu_online(bootstrap_processor, true);
 386         set_cpu_present(bootstrap_processor, true);
 387 }
 388
 389
 390
 391 /*
 392 ** inventory.c:do_inventory() hasn't yet been run and thus we
 393 ** don't 'discover' the additional CPUs until later.
 394 */
 395 void __init smp_prepare_cpus(unsigned int max_cpus)
 396 {
 397         int cpu;
 398
 399         for_each_possible_cpu(cpu)
 400                 spin_lock_init(&per_cpu(ipi_lock, cpu));
 401
 402         init_cpu_present(cpumask_of(0));
 403
 404         parisc_max_cpus = max_cpus;
 405         if (!max_cpus)
 406                 printk(KERN_INFO "SMP mode deactivated.\n");
 407 }
 408
 409
 410 void smp_cpus_done(unsigned int cpu_max)
 411 {
 412         return;
 413 }
 414
 415
 416 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 417 {
 418         if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
 419                 return -ENOSYS;
 420
 421         return cpu_online(cpu) ? 0 : -ENOSYS;
 422 }
 423
 424 #ifdef CONFIG_PROC_FS
 425 int setup_profiling_timer(unsigned int multiplier)
 426 {
 427         return -EINVAL;
 428 }
 429 #endif