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 #include <linux/slab.h> 22 23 #include <linux/kernel.h> 24 #include <linux/module.h> 25 #include <linux/sched.h> 26 #include <linux/init.h> 27 #include <linux/interrupt.h> 28 #include <linux/smp.h> 29 #include <linux/kernel_stat.h> 30 #include <linux/mm.h> 31 #include <linux/err.h> 32 #include <linux/delay.h> 33 #include <linux/bitops.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 54 static 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, ...) 60 #endif /* DEBUG_SMP */ 61 62 DEFINE_SPINLOCK(smp_lock); 63 64 volatile struct task_struct *smp_init_current_idle_task; 65 66 static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */ 67 68 static int parisc_max_cpus __read_mostly = 1; 69 70 /* online cpus are ones that we've managed to bring up completely 71 * possible cpus are all valid cpu 72 * present cpus are all detected cpu 73 * 74 * On startup we bring up the "possible" cpus. Since we discover 75 * CPUs later, we add them as hotplug, so the possible cpu mask is 76 * empty in the beginning. 77 */ 78 79 cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */ 80 cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */ 81 82 EXPORT_SYMBOL(cpu_online_map); 83 EXPORT_SYMBOL(cpu_possible_map); 84 85 DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED; 86 87 enum ipi_message_type { 88 IPI_NOP=0, 89 IPI_RESCHEDULE=1, 90 IPI_CALL_FUNC, 91 IPI_CALL_FUNC_SINGLE, 92 IPI_CPU_START, 93 IPI_CPU_STOP, 94 IPI_CPU_TEST 95 }; 96 97 98 /********** SMP inter processor interrupt and communication routines */ 99 100 #undef PER_CPU_IRQ_REGION 101 #ifdef PER_CPU_IRQ_REGION 102 /* XXX REVISIT Ignore for now. 103 ** *May* need this "hook" to register IPI handler 104 ** once we have perCPU ExtIntr switch tables. 105 */ 106 static void 107 ipi_init(int cpuid) 108 { 109 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 110 111 if(cpu_online(cpuid) ) 112 { 113 switch_to_idle_task(current); 114 } 115 116 return; 117 } 118 #endif 119 120 121 /* 122 ** Yoink this CPU from the runnable list... 123 ** 124 */ 125 static void 126 halt_processor(void) 127 { 128 /* REVISIT : redirect I/O Interrupts to another CPU? */ 129 /* REVISIT : does PM *know* this CPU isn't available? */ 130 cpu_clear(smp_processor_id(), cpu_online_map); 131 local_irq_disable(); 132 for (;;) 133 ; 134 } 135 136 137 irqreturn_t 138 ipi_interrupt(int irq, void *dev_id) 139 { 140 int this_cpu = smp_processor_id(); 141 struct cpuinfo_parisc *p = &cpu_data[this_cpu]; 142 unsigned long ops; 143 unsigned long flags; 144 145 /* Count this now; we may make a call that never returns. */ 146 p->ipi_count++; 147 148 mb(); /* Order interrupt and bit testing. */ 149 150 for (;;) { 151 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 152 spin_lock_irqsave(lock, flags); 153 ops = p->pending_ipi; 154 p->pending_ipi = 0; 155 spin_unlock_irqrestore(lock, flags); 156 157 mb(); /* Order bit clearing and data access. */ 158 159 if (!ops) 160 break; 161 162 while (ops) { 163 unsigned long which = ffz(~ops); 164 165 ops &= ~(1 << which); 166 167 switch (which) { 168 case IPI_NOP: 169 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 170 break; 171 172 case IPI_RESCHEDULE: 173 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 174 /* 175 * Reschedule callback. Everything to be 176 * done is done by the interrupt return path. 177 */ 178 break; 179 180 case IPI_CALL_FUNC: 181 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 182 generic_smp_call_function_interrupt(); 183 break; 184 185 case IPI_CALL_FUNC_SINGLE: 186 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu); 187 generic_smp_call_function_single_interrupt(); 188 break; 189 190 case IPI_CPU_START: 191 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 192 break; 193 194 case IPI_CPU_STOP: 195 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 196 halt_processor(); 197 break; 198 199 case IPI_CPU_TEST: 200 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 201 break; 202 203 default: 204 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 205 this_cpu, which); 206 return IRQ_NONE; 207 } /* Switch */ 208 /* let in any pending interrupts */ 209 local_irq_enable(); 210 local_irq_disable(); 211 } /* while (ops) */ 212 } 213 return IRQ_HANDLED; 214 } 215 216 217 static inline void 218 ipi_send(int cpu, enum ipi_message_type op) 219 { 220 struct cpuinfo_parisc *p = &cpu_data[cpu]; 221 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 222 unsigned long flags; 223 224 spin_lock_irqsave(lock, flags); 225 p->pending_ipi |= 1 << op; 226 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa); 227 spin_unlock_irqrestore(lock, flags); 228 } 229 230 static void 231 send_IPI_mask(cpumask_t mask, enum ipi_message_type op) 232 { 233 int cpu; 234 235 for_each_cpu_mask(cpu, mask) 236 ipi_send(cpu, op); 237 } 238 239 static inline void 240 send_IPI_single(int dest_cpu, enum ipi_message_type op) 241 { 242 if (dest_cpu == NO_PROC_ID) { 243 BUG(); 244 return; 245 } 246 247 ipi_send(dest_cpu, op); 248 } 249 250 static inline void 251 send_IPI_allbutself(enum ipi_message_type op) 252 { 253 int i; 254 255 for_each_online_cpu(i) { 256 if (i != smp_processor_id()) 257 send_IPI_single(i, op); 258 } 259 } 260 261 262 inline void 263 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 264 265 static inline void 266 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); } 267 268 void 269 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 270 271 void 272 smp_send_all_nop(void) 273 { 274 send_IPI_allbutself(IPI_NOP); 275 } 276 277 void arch_send_call_function_ipi(cpumask_t mask) 278 { 279 send_IPI_mask(mask, IPI_CALL_FUNC); 280 } 281 282 void arch_send_call_function_single_ipi(int cpu) 283 { 284 send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE); 285 } 286 287 /* 288 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu() 289 * as we want to ensure all TLB's flushed before proceeding. 290 */ 291 292 void 293 smp_flush_tlb_all(void) 294 { 295 on_each_cpu(flush_tlb_all_local, NULL, 1); 296 } 297 298 /* 299 * Called by secondaries to update state and initialize CPU registers. 300 */ 301 static void __init 302 smp_cpu_init(int cpunum) 303 { 304 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ 305 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 306 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 307 308 /* Set modes and Enable floating point coprocessor */ 309 (void) init_per_cpu(cpunum); 310 311 disable_sr_hashing(); 312 313 mb(); 314 315 /* Well, support 2.4 linux scheme as well. */ 316 if (cpu_test_and_set(cpunum, cpu_online_map)) 317 { 318 extern void machine_halt(void); /* arch/parisc.../process.c */ 319 320 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 321 machine_halt(); 322 } 323 324 /* Initialise the idle task for this CPU */ 325 atomic_inc(&init_mm.mm_count); 326 current->active_mm = &init_mm; 327 if(current->mm) 328 BUG(); 329 enter_lazy_tlb(&init_mm, current); 330 331 init_IRQ(); /* make sure no IRQs are enabled or pending */ 332 start_cpu_itimer(); 333 } 334 335 336 /* 337 * Slaves start using C here. Indirectly called from smp_slave_stext. 338 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 339 */ 340 void __init smp_callin(void) 341 { 342 int slave_id = cpu_now_booting; 343 344 smp_cpu_init(slave_id); 345 preempt_disable(); 346 347 flush_cache_all_local(); /* start with known state */ 348 flush_tlb_all_local(NULL); 349 350 local_irq_enable(); /* Interrupts have been off until now */ 351 352 cpu_idle(); /* Wait for timer to schedule some work */ 353 354 /* NOTREACHED */ 355 panic("smp_callin() AAAAaaaaahhhh....\n"); 356 } 357 358 /* 359 * Bring one cpu online. 360 */ 361 int __cpuinit smp_boot_one_cpu(int cpuid) 362 { 363 struct task_struct *idle; 364 long timeout; 365 366 /* 367 * Create an idle task for this CPU. Note the address wed* give 368 * to kernel_thread is irrelevant -- it's going to start 369 * where OS_BOOT_RENDEVZ vector in SAL says to start. But 370 * this gets all the other task-y sort of data structures set 371 * up like we wish. We need to pull the just created idle task 372 * off the run queue and stuff it into the init_tasks[] array. 373 * Sheesh . . . 374 */ 375 376 idle = fork_idle(cpuid); 377 if (IS_ERR(idle)) 378 panic("SMP: fork failed for CPU:%d", cpuid); 379 380 task_thread_info(idle)->cpu = cpuid; 381 382 /* Let _start know what logical CPU we're booting 383 ** (offset into init_tasks[],cpu_data[]) 384 */ 385 cpu_now_booting = cpuid; 386 387 /* 388 ** boot strap code needs to know the task address since 389 ** it also contains the process stack. 390 */ 391 smp_init_current_idle_task = idle ; 392 mb(); 393 394 printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa); 395 396 /* 397 ** This gets PDC to release the CPU from a very tight loop. 398 ** 399 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 400 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 401 ** is executed after receiving the rendezvous signal (an interrupt to 402 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 403 ** contents of memory are valid." 404 */ 405 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa); 406 mb(); 407 408 /* 409 * OK, wait a bit for that CPU to finish staggering about. 410 * Slave will set a bit when it reaches smp_cpu_init(). 411 * Once the "monarch CPU" sees the bit change, it can move on. 412 */ 413 for (timeout = 0; timeout < 10000; timeout++) { 414 if(cpu_online(cpuid)) { 415 /* Which implies Slave has started up */ 416 cpu_now_booting = 0; 417 smp_init_current_idle_task = NULL; 418 goto alive ; 419 } 420 udelay(100); 421 barrier(); 422 } 423 424 put_task_struct(idle); 425 idle = NULL; 426 427 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 428 return -1; 429 430 alive: 431 /* Remember the Slave data */ 432 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 433 cpuid, timeout * 100); 434 return 0; 435 } 436 437 void __devinit smp_prepare_boot_cpu(void) 438 { 439 int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */ 440 441 /* Setup BSP mappings */ 442 printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor); 443 444 cpu_set(bootstrap_processor, cpu_online_map); 445 cpu_set(bootstrap_processor, cpu_present_map); 446 } 447 448 449 450 /* 451 ** inventory.c:do_inventory() hasn't yet been run and thus we 452 ** don't 'discover' the additional CPUs until later. 453 */ 454 void __init smp_prepare_cpus(unsigned int max_cpus) 455 { 456 cpus_clear(cpu_present_map); 457 cpu_set(0, cpu_present_map); 458 459 parisc_max_cpus = max_cpus; 460 if (!max_cpus) 461 printk(KERN_INFO "SMP mode deactivated.\n"); 462 } 463 464 465 void smp_cpus_done(unsigned int cpu_max) 466 { 467 return; 468 } 469 470 471 int __cpuinit __cpu_up(unsigned int cpu) 472 { 473 if (cpu != 0 && cpu < parisc_max_cpus) 474 smp_boot_one_cpu(cpu); 475 476 return cpu_online(cpu) ? 0 : -ENOSYS; 477 } 478 479 #ifdef CONFIG_PROC_FS 480 int __init 481 setup_profiling_timer(unsigned int multiplier) 482 { 483 return -EINVAL; 484 } 485 #endif 486