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 #include <linux/kgdb.h>
  33
  34 #include <linux/atomic.h>
  35 #include <asm/current.h>
  36 #include <asm/delay.h>
  37 #include <asm/tlbflush.h>
  38
  39 #include <asm/io.h>
  40 #include <asm/irq.h>            /* for CPU_IRQ_REGION and friends */
  41 #include <asm/mmu_context.h>
  42 #include <asm/page.h>
  43 #include <asm/processor.h>
  44 #include <asm/ptrace.h>
  45 #include <asm/unistd.h>
  46 #include <asm/cacheflush.h>
  47
  48 #undef DEBUG_SMP
  49 #ifdef DEBUG_SMP
  50 static int smp_debug_lvl = 0;
  51 #define smp_debug(lvl, printargs...)            \
  52                 if (lvl >= smp_debug_lvl)       \
  53                         printk(printargs);
  54 #else
  55 #define smp_debug(lvl, ...)     do { } while(0)
  56 #endif /* DEBUG_SMP */
  57
  58 volatile struct task_struct *smp_init_current_idle_task;
  59
  60 /* track which CPU is booting */
  61 static volatile int cpu_now_booting;
  62
  63 static int parisc_max_cpus = 1;
  64
  65 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
  66
  67 enum ipi_message_type {
  68         IPI_NOP=0,
  69         IPI_RESCHEDULE=1,
  70         IPI_CALL_FUNC,
  71         IPI_CPU_START,
  72         IPI_CPU_STOP,
  73         IPI_CPU_TEST,
  74 #ifdef CONFIG_KGDB
  75         IPI_ENTER_KGDB,
  76 #endif
  77 };
  78
  79
  80 /********** SMP inter processor interrupt and communication routines */
  81
  82 #undef PER_CPU_IRQ_REGION
  83 #ifdef PER_CPU_IRQ_REGION
  84 /* XXX REVISIT Ignore for now.
  85 **    *May* need this "hook" to register IPI handler
  86 **    once we have perCPU ExtIntr switch tables.
  87 */
  88 static void
  89 ipi_init(int cpuid)
  90 {
  91 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
  92
  93         if(cpu_online(cpuid) )
  94         {
  95                 switch_to_idle_task(current);
  96         }
  97
  98         return;
  99 }
 100 #endif
 101
 102
 103 /*
 104 ** Yoink this CPU from the runnable list...
 105 **
 106 */
 107 static void
 108 halt_processor(void)
 109 {
 110         /* REVISIT : redirect I/O Interrupts to another CPU? */
 111         /* REVISIT : does PM *know* this CPU isn't available? */
 112         set_cpu_online(smp_processor_id(), false);
 113         local_irq_disable();
 114         __pdc_cpu_rendezvous();
 115         for (;;)
 116                 ;
 117 }
 118
 119
 120 irqreturn_t __irq_entry
 121 ipi_interrupt(int irq, void *dev_id)
 122 {
 123         int this_cpu = smp_processor_id();
 124         struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
 125         unsigned long ops;
 126         unsigned long flags;
 127
 128         for (;;) {
 129                 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
 130                 spin_lock_irqsave(lock, flags);
 131                 ops = p->pending_ipi;
 132                 p->pending_ipi = 0;
 133                 spin_unlock_irqrestore(lock, flags);
 134
 135                 mb(); /* Order bit clearing and data access. */
 136
 137                 if (!ops)
 138                     break;
 139
 140                 while (ops) {
 141                         unsigned long which = ffz(~ops);
 142
 143                         ops &= ~(1 << which);
 144
 145                         switch (which) {
 146                         case IPI_NOP:
 147                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
 148                                 break;
 149
 150                         case IPI_RESCHEDULE:
 151                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
 152                                 inc_irq_stat(irq_resched_count);
 153                                 scheduler_ipi();
 154                                 break;
 155
 156                         case IPI_CALL_FUNC:
 157                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
 158                                 inc_irq_stat(irq_call_count);
 159                                 generic_smp_call_function_interrupt();
 160                                 break;
 161
 162                         case IPI_CPU_START:
 163                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 164                                 break;
 165
 166                         case IPI_CPU_STOP:
 167                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
 168                                 halt_processor();
 169                                 break;
 170
 171                         case IPI_CPU_TEST:
 172                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 173                                 break;
 174 #ifdef CONFIG_KGDB
 175                         case IPI_ENTER_KGDB:
 176                                 smp_debug(100, KERN_DEBUG "CPU%d ENTER_KGDB\n", this_cpu);
 177                                 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 178                                 break;
 179 #endif
 180                         default:
 181                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 182                                         this_cpu, which);
 183                                 return IRQ_NONE;
 184                         } /* Switch */
 185
 186                         /* before doing more, let in any pending interrupts */
 187                         if (ops) {
 188                                 local_irq_enable();
 189                                 local_irq_disable();
 190                         }
 191                 } /* while (ops) */
 192         }
 193         return IRQ_HANDLED;
 194 }
 195
 196
 197 static inline void
 198 ipi_send(int cpu, enum ipi_message_type op)
 199 {
 200         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
 201         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
 202         unsigned long flags;
 203
 204         spin_lock_irqsave(lock, flags);
 205         p->pending_ipi |= 1 << op;
 206         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
 207         spin_unlock_irqrestore(lock, flags);
 208 }
 209
 210 static void
 211 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
 212 {
 213         int cpu;
 214
 215         for_each_cpu(cpu, mask)
 216                 ipi_send(cpu, op);
 217 }
 218
 219 static inline void
 220 send_IPI_single(int dest_cpu, enum ipi_message_type op)
 221 {
 222         BUG_ON(dest_cpu == NO_PROC_ID);
 223
 224         ipi_send(dest_cpu, op);
 225 }
 226
 227 static inline void
 228 send_IPI_allbutself(enum ipi_message_type op)
 229 {
 230         int i;
 231
 232         for_each_online_cpu(i) {
 233                 if (i != smp_processor_id())
 234                         send_IPI_single(i, op);
 235         }
 236 }
 237
 238 #ifdef CONFIG_KGDB
 239 void kgdb_roundup_cpus(void)
 240 {
 241         send_IPI_allbutself(IPI_ENTER_KGDB);
 242 }
 243 #endif
 244
 245 inline void
 246 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
 247
 248 void
 249 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
 250
 251 void
 252 smp_send_all_nop(void)
 253 {
 254         send_IPI_allbutself(IPI_NOP);
 255 }
 256
 257 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 258 {
 259         send_IPI_mask(mask, IPI_CALL_FUNC);
 260 }
 261
 262 void arch_send_call_function_single_ipi(int cpu)
 263 {
 264         send_IPI_single(cpu, IPI_CALL_FUNC);
 265 }
 266
 267 /*
 268  * Called by secondaries to update state and initialize CPU registers.
 269  */
 270 static void __init
 271 smp_cpu_init(int cpunum)
 272 {
 273         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 274         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 275
 276         /* Set modes and Enable floating point coprocessor */
 277         init_per_cpu(cpunum);
 278
 279         disable_sr_hashing();
 280
 281         mb();
 282
 283         /* Well, support 2.4 linux scheme as well. */
 284         if (cpu_online(cpunum)) {
 285                 extern void machine_halt(void); /* arch/parisc.../process.c */
 286
 287                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
 288                 machine_halt();
 289         }
 290
 291         notify_cpu_starting(cpunum);
 292
 293         set_cpu_online(cpunum, true);
 294
 295         /* Initialise the idle task for this CPU */
 296         mmgrab(&init_mm);
 297         current->active_mm = &init_mm;
 298         BUG_ON(current->mm);
 299         enter_lazy_tlb(&init_mm, current);
 300
 301         init_IRQ();   /* make sure no IRQs are enabled or pending */
 302         start_cpu_itimer();
 303 }
 304
 305
 306 /*
 307  * Slaves start using C here. Indirectly called from smp_slave_stext.
 308  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
 309  */
 310 void __init smp_callin(unsigned long pdce_proc)
 311 {
 312         int slave_id = cpu_now_booting;
 313
 314 #ifdef CONFIG_64BIT
 315         WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
 316                         | PAGE0->mem_pdc) != pdce_proc);
 317 #endif
 318
 319         smp_cpu_init(slave_id);
 320
 321         flush_cache_all_local(); /* start with known state */
 322         flush_tlb_all_local(NULL);
 323
 324         local_irq_enable();  /* Interrupts have been off until now */
 325
 326         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 327
 328         /* NOTREACHED */
 329         panic("smp_callin() AAAAaaaaahhhh....\n");
 330 }
 331
 332 /*
 333  * Bring one cpu online.
 334  */
 335 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 336 {
 337         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
 338         long timeout;
 339
 340         task_thread_info(idle)->cpu = cpuid;
 341
 342         /* Let _start know what logical CPU we're booting
 343         ** (offset into init_tasks[],cpu_data[])
 344         */
 345         cpu_now_booting = cpuid;
 346
 347         /*
 348         ** boot strap code needs to know the task address since
 349         ** it also contains the process stack.
 350         */
 351         smp_init_current_idle_task = idle ;
 352         mb();
 353
 354         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
 355
 356         /*
 357         ** This gets PDC to release the CPU from a very tight loop.
 358         **
 359         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
 360         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
 361         ** is executed after receiving the rendezvous signal (an interrupt to
 362         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
 363         ** contents of memory are valid."
 364         */
 365         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
 366         mb();
 367
 368         /*
 369          * OK, wait a bit for that CPU to finish staggering about.
 370          * Slave will set a bit when it reaches smp_cpu_init().
 371          * Once the "monarch CPU" sees the bit change, it can move on.
 372          */
 373         for (timeout = 0; timeout < 10000; timeout++) {
 374                 if(cpu_online(cpuid)) {
 375                         /* Which implies Slave has started up */
 376                         cpu_now_booting = 0;
 377                         smp_init_current_idle_task = NULL;
 378                         goto alive ;
 379                 }
 380                 udelay(100);
 381                 barrier();
 382         }
 383         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 384         return -1;
 385
 386 alive:
 387         /* Remember the Slave data */
 388         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
 389                 cpuid, timeout * 100);
 390         return 0;
 391 }
 392
 393 void __init smp_prepare_boot_cpu(void)
 394 {
 395         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
 396
 397         /* Setup BSP mappings */
 398         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
 399
 400         set_cpu_online(bootstrap_processor, true);
 401         set_cpu_present(bootstrap_processor, true);
 402 }
 403
 404
 405
 406 /*
 407 ** inventory.c:do_inventory() hasn't yet been run and thus we
 408 ** don't 'discover' the additional CPUs until later.
 409 */
 410 void __init smp_prepare_cpus(unsigned int max_cpus)
 411 {
 412         int cpu;
 413
 414         for_each_possible_cpu(cpu)
 415                 spin_lock_init(&per_cpu(ipi_lock, cpu));
 416
 417         init_cpu_present(cpumask_of(0));
 418
 419         parisc_max_cpus = max_cpus;
 420         if (!max_cpus)
 421                 printk(KERN_INFO "SMP mode deactivated.\n");
 422 }
 423
 424
 425 void smp_cpus_done(unsigned int cpu_max)
 426 {
 427         return;
 428 }
 429
 430
 431 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 432 {
 433         if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
 434                 return -ENOSYS;
 435
 436         return cpu_online(cpu) ? 0 : -ENOSYS;
 437 }
 438
 439 #ifdef CONFIG_PROC_FS
 440 int setup_profiling_timer(unsigned int multiplier)
 441 {
 442         return -EINVAL;
 443 }
 444 #endif