1/* 2** SMP Support 3** 4** Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 5** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com> 6** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org> 7** 8** Lots of stuff stolen from arch/alpha/kernel/smp.c 9** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^) 10** 11** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work. 12** -grant (1/12/2001) 13** 14** This program is free software; you can redistribute it and/or modify 15** it under the terms of the GNU General Public License as published by 16** the Free Software Foundation; either version 2 of the License, or 17** (at your option) any later version. 18*/ 19#include <linux/types.h> 20#include <linux/spinlock.h> 21 22#include <linux/kernel.h> 23#include <linux/module.h> 24#include <linux/sched.h> 25#include <linux/init.h> 26#include <linux/interrupt.h> 27#include <linux/smp.h> 28#include <linux/kernel_stat.h> 29#include <linux/mm.h> 30#include <linux/err.h> 31#include <linux/delay.h> 32#include <linux/bitops.h> 33#include <linux/ftrace.h> 34 35#include <asm/system.h> 36#include <asm/atomic.h> 37#include <asm/current.h> 38#include <asm/delay.h> 39#include <asm/tlbflush.h> 40 41#include <asm/io.h> 42#include <asm/irq.h> /* for CPU_IRQ_REGION and friends */ 43#include <asm/mmu_context.h> 44#include <asm/page.h> 45#include <asm/pgtable.h> 46#include <asm/pgalloc.h> 47#include <asm/processor.h> 48#include <asm/ptrace.h> 49#include <asm/unistd.h> 50#include <asm/cacheflush.h> 51 52#undef DEBUG_SMP 53#ifdef DEBUG_SMP 54static int smp_debug_lvl = 0; 55#define smp_debug(lvl, printargs...) \ 56 if (lvl >= smp_debug_lvl) \ 57 printk(printargs); 58#else 59#define smp_debug(lvl, ...) do { } while(0) 60#endif /* DEBUG_SMP */ 61 62volatile struct task_struct *smp_init_current_idle_task; 63 64/* track which CPU is booting */ 65static volatile int cpu_now_booting __cpuinitdata; 66 67static int parisc_max_cpus __cpuinitdata = 1; 68 69static DEFINE_PER_CPU(spinlock_t, ipi_lock); 70 71enum ipi_message_type { 72 IPI_NOP=0, 73 IPI_RESCHEDULE=1, 74 IPI_CALL_FUNC, 75 IPI_CALL_FUNC_SINGLE, 76 IPI_CPU_START, 77 IPI_CPU_STOP, 78 IPI_CPU_TEST 79}; 80 81 82/********** SMP inter processor interrupt and communication routines */ 83 84#undef PER_CPU_IRQ_REGION 85#ifdef PER_CPU_IRQ_REGION 86static void 87ipi_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*/ 105static void 106halt_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 for (;;) 113 ; 114} 115 116 117irqreturn_t __irq_entry 118ipi_interrupt(int irq, void *dev_id) 119{ 120 int this_cpu = smp_processor_id(); 121 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu); 122 unsigned long ops; 123 unsigned long flags; 124 125 /* Count this now; we may make a call that never returns. */ 126 p->ipi_count++; 127 128 mb(); /* Order interrupt and bit testing. */ 129 130 for (;;) { 131 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 132 spin_lock_irqsave(lock, flags); 133 ops = p->pending_ipi; 134 p->pending_ipi = 0; 135 spin_unlock_irqrestore(lock, flags); 136 137 mb(); /* Order bit clearing and data access. */ 138 139 if (!ops) 140 break; 141 142 while (ops) { 143 unsigned long which = ffz(~ops); 144 145 ops &= ~(1 << which); 146 147 switch (which) { 148 case IPI_NOP: 149 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 150 break; 151 152 case IPI_RESCHEDULE: 153 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 154 /* 155 * Reschedule callback. Everything to be 156 * done is done by the interrupt return path. 157 */ 158 break; 159 160 case IPI_CALL_FUNC: 161 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 162 generic_smp_call_function_interrupt(); 163 break; 164 165 case IPI_CALL_FUNC_SINGLE: 166 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu); 167 generic_smp_call_function_single_interrupt(); 168 break; 169 170 case IPI_CPU_START: 171 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 172 break; 173 174 case IPI_CPU_STOP: 175 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 176 halt_processor(); 177 break; 178 179 case IPI_CPU_TEST: 180 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 181 break; 182 183 default: 184 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 185 this_cpu, which); 186 return IRQ_NONE; 187 } /* Switch */ 188 /* let in any pending interrupts */ 189 local_irq_enable(); 190 local_irq_disable(); 191 } /* while (ops) */ 192 } 193 return IRQ_HANDLED; 194} 195 196 197static inline void 198ipi_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 210static void 211send_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 219static inline void 220send_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 227static inline void 228send_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 239inline void 240smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 241 242static inline void 243smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); } 244 245void 246smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 247 248void 249smp_send_all_nop(void) 250{ 251 send_IPI_allbutself(IPI_NOP); 252} 253 254void arch_send_call_function_ipi_mask(const struct cpumask *mask) 255{ 256 send_IPI_mask(mask, IPI_CALL_FUNC); 257} 258 259void arch_send_call_function_single_ipi(int cpu) 260{ 261 send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE); 262} 263 264/* 265 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu() 266 * as we want to ensure all TLB's flushed before proceeding. 267 */ 268 269void 270smp_flush_tlb_all(void) 271{ 272 on_each_cpu(flush_tlb_all_local, NULL, 1); 273} 274 275/* 276 * Called by secondaries to update state and initialize CPU registers. 277 */ 278static void __init 279smp_cpu_init(int cpunum) 280{ 281 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ 282 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 283 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 284 285 /* Set modes and Enable floating point coprocessor */ 286 (void) init_per_cpu(cpunum); 287 288 disable_sr_hashing(); 289 290 mb(); 291 292 /* Well, support 2.4 linux scheme as well. */ 293 if (cpu_isset(cpunum, cpu_online_map)) 294 { 295 extern void machine_halt(void); /* arch/parisc.../process.c */ 296 297 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 298 machine_halt(); 299 } 300 set_cpu_online(cpunum, true); 301 302 /* Initialise the idle task for this CPU */ 303 atomic_inc(&init_mm.mm_count); 304 current->active_mm = &init_mm; 305 BUG_ON(current->mm); 306 enter_lazy_tlb(&init_mm, current); 307 308 init_IRQ(); /* make sure no IRQs are enabled or pending */ 309 start_cpu_itimer(); 310} 311 312 313/* 314 * Slaves start using C here. Indirectly called from smp_slave_stext. 315 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 316 */ 317void __init smp_callin(void) 318{ 319 int slave_id = cpu_now_booting; 320 321 smp_cpu_init(slave_id); 322 preempt_disable(); 323 324 flush_cache_all_local(); /* start with known state */ 325 flush_tlb_all_local(NULL); 326 327 local_irq_enable(); /* Interrupts have been off until now */ 328 329 cpu_idle(); /* Wait for timer to schedule some work */ 330 331 /* NOTREACHED */ 332 panic("smp_callin() AAAAaaaaahhhh....\n"); 333} 334 335/* 336 * Bring one cpu online. 337 */ 338int __cpuinit smp_boot_one_cpu(int cpuid) 339{ 340 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 341 struct task_struct *idle; 342 long timeout; 343 344 /* 345 * Create an idle task for this CPU. Note the address wed* give 346 * to kernel_thread is irrelevant -- it's going to start 347 * where OS_BOOT_RENDEVZ vector in SAL says to start. But 348 * this gets all the other task-y sort of data structures set 349 * up like we wish. We need to pull the just created idle task 350 * off the run queue and stuff it into the init_tasks[] array. 351 * Sheesh . . . 352 */ 353 354 idle = fork_idle(cpuid); 355 if (IS_ERR(idle)) 356 panic("SMP: fork failed for CPU:%d", cpuid); 357 358 task_thread_info(idle)->cpu = cpuid; 359 360 /* Let _start know what logical CPU we're booting 361 ** (offset into init_tasks[],cpu_data[]) 362 */ 363 cpu_now_booting = cpuid; 364 365 /* 366 ** boot strap code needs to know the task address since 367 ** it also contains the process stack. 368 */ 369 smp_init_current_idle_task = idle ; 370 mb(); 371 372 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 373 374 /* 375 ** This gets PDC to release the CPU from a very tight loop. 376 ** 377 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 378 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 379 ** is executed after receiving the rendezvous signal (an interrupt to 380 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 381 ** contents of memory are valid." 382 */ 383 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 384 mb(); 385 386 /* 387 * OK, wait a bit for that CPU to finish staggering about. 388 * Slave will set a bit when it reaches smp_cpu_init(). 389 * Once the "monarch CPU" sees the bit change, it can move on. 390 */ 391 for (timeout = 0; timeout < 10000; timeout++) { 392 if(cpu_online(cpuid)) { 393 /* Which implies Slave has started up */ 394 cpu_now_booting = 0; 395 smp_init_current_idle_task = NULL; 396 goto alive ; 397 } 398 udelay(100); 399 barrier(); 400 } 401 402 put_task_struct(idle); 403 idle = NULL; 404 405 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 406 return -1; 407 408alive: 409 /* Remember the Slave data */ 410 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 411 cpuid, timeout * 100); 412 return 0; 413} 414 415void __init smp_prepare_boot_cpu(void) 416{ 417 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 418 419 /* Setup BSP mappings */ 420 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 421 422 set_cpu_online(bootstrap_processor, true); 423 set_cpu_present(bootstrap_processor, true); 424} 425 426 427 428/* 429** inventory.c:do_inventory() hasn't yet been run and thus we 430** don't 'discover' the additional CPUs until later. 431*/ 432void __init smp_prepare_cpus(unsigned int max_cpus) 433{ 434 int cpu; 435 436 for_each_possible_cpu(cpu) 437 spin_lock_init(&per_cpu(ipi_lock, cpu)); 438 439 init_cpu_present(cpumask_of(0)); 440 441 parisc_max_cpus = max_cpus; 442 if (!max_cpus) 443 printk(KERN_INFO "SMP mode deactivated.\n"); 444} 445 446 447void smp_cpus_done(unsigned int cpu_max) 448{ 449 return; 450} 451 452 453int __cpuinit __cpu_up(unsigned int cpu) 454{ 455 if (cpu != 0 && cpu < parisc_max_cpus) 456 smp_boot_one_cpu(cpu); 457 458 return cpu_online(cpu) ? 0 : -ENOSYS; 459} 460 461#ifdef CONFIG_PROC_FS 462int __init 463setup_profiling_timer(unsigned int multiplier) 464{ 465 return -EINVAL; 466} 467#endif 468