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