1 /* 2 * SMP support for ppc. 3 * 4 * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great 5 * deal of code from the sparc and intel versions. 6 * 7 * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu> 8 * 9 * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and 10 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 18 #undef DEBUG 19 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/sched.h> 23 #include <linux/smp.h> 24 #include <linux/interrupt.h> 25 #include <linux/delay.h> 26 #include <linux/init.h> 27 #include <linux/spinlock.h> 28 #include <linux/cache.h> 29 #include <linux/err.h> 30 #include <linux/sysdev.h> 31 #include <linux/cpu.h> 32 #include <linux/notifier.h> 33 #include <linux/topology.h> 34 35 #include <asm/ptrace.h> 36 #include <asm/atomic.h> 37 #include <asm/irq.h> 38 #include <asm/page.h> 39 #include <asm/pgtable.h> 40 #include <asm/prom.h> 41 #include <asm/smp.h> 42 #include <asm/time.h> 43 #include <asm/machdep.h> 44 #include <asm/cputable.h> 45 #include <asm/system.h> 46 #include <asm/mpic.h> 47 #include <asm/vdso_datapage.h> 48 #ifdef CONFIG_PPC64 49 #include <asm/paca.h> 50 #endif 51 52 #ifdef DEBUG 53 #include <asm/udbg.h> 54 #define DBG(fmt...) udbg_printf(fmt) 55 #else 56 #define DBG(fmt...) 57 #endif 58 59 int smp_hw_index[NR_CPUS]; 60 struct thread_info *secondary_ti; 61 62 cpumask_t cpu_possible_map = CPU_MASK_NONE; 63 cpumask_t cpu_online_map = CPU_MASK_NONE; 64 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE; 65 66 EXPORT_SYMBOL(cpu_online_map); 67 EXPORT_SYMBOL(cpu_possible_map); 68 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); 69 70 /* SMP operations for this machine */ 71 struct smp_ops_t *smp_ops; 72 73 static volatile unsigned int cpu_callin_map[NR_CPUS]; 74 75 int smt_enabled_at_boot = 1; 76 77 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; 78 79 #ifdef CONFIG_PPC64 80 void __devinit smp_generic_kick_cpu(int nr) 81 { 82 BUG_ON(nr < 0 || nr >= NR_CPUS); 83 84 /* 85 * The processor is currently spinning, waiting for the 86 * cpu_start field to become non-zero After we set cpu_start, 87 * the processor will continue on to secondary_start 88 */ 89 paca[nr].cpu_start = 1; 90 smp_mb(); 91 } 92 #endif 93 94 void smp_message_recv(int msg) 95 { 96 switch(msg) { 97 case PPC_MSG_CALL_FUNCTION: 98 generic_smp_call_function_interrupt(); 99 break; 100 case PPC_MSG_RESCHEDULE: 101 /* XXX Do we have to do this? */ 102 set_need_resched(); 103 break; 104 case PPC_MSG_CALL_FUNC_SINGLE: 105 generic_smp_call_function_single_interrupt(); 106 break; 107 case PPC_MSG_DEBUGGER_BREAK: 108 if (crash_ipi_function_ptr) { 109 crash_ipi_function_ptr(get_irq_regs()); 110 break; 111 } 112 #ifdef CONFIG_DEBUGGER 113 debugger_ipi(get_irq_regs()); 114 break; 115 #endif /* CONFIG_DEBUGGER */ 116 /* FALLTHROUGH */ 117 default: 118 printk("SMP %d: smp_message_recv(): unknown msg %d\n", 119 smp_processor_id(), msg); 120 break; 121 } 122 } 123 124 void smp_send_reschedule(int cpu) 125 { 126 if (likely(smp_ops)) 127 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); 128 } 129 130 void arch_send_call_function_single_ipi(int cpu) 131 { 132 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); 133 } 134 135 void arch_send_call_function_ipi(cpumask_t mask) 136 { 137 unsigned int cpu; 138 139 for_each_cpu_mask(cpu, mask) 140 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION); 141 } 142 143 #ifdef CONFIG_DEBUGGER 144 void smp_send_debugger_break(int cpu) 145 { 146 if (likely(smp_ops)) 147 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); 148 } 149 #endif 150 151 #ifdef CONFIG_KEXEC 152 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 153 { 154 crash_ipi_function_ptr = crash_ipi_callback; 155 if (crash_ipi_callback && smp_ops) { 156 mb(); 157 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK); 158 } 159 } 160 #endif 161 162 static void stop_this_cpu(void *dummy) 163 { 164 local_irq_disable(); 165 while (1) 166 ; 167 } 168 169 void smp_send_stop(void) 170 { 171 smp_call_function(stop_this_cpu, NULL, 0); 172 } 173 174 struct thread_info *current_set[NR_CPUS]; 175 176 static void __devinit smp_store_cpu_info(int id) 177 { 178 per_cpu(pvr, id) = mfspr(SPRN_PVR); 179 } 180 181 static void __init smp_create_idle(unsigned int cpu) 182 { 183 struct task_struct *p; 184 185 /* create a process for the processor */ 186 p = fork_idle(cpu); 187 if (IS_ERR(p)) 188 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); 189 #ifdef CONFIG_PPC64 190 paca[cpu].__current = p; 191 paca[cpu].kstack = (unsigned long) task_thread_info(p) 192 + THREAD_SIZE - STACK_FRAME_OVERHEAD; 193 #endif 194 current_set[cpu] = task_thread_info(p); 195 task_thread_info(p)->cpu = cpu; 196 } 197 198 void __init smp_prepare_cpus(unsigned int max_cpus) 199 { 200 unsigned int cpu; 201 202 DBG("smp_prepare_cpus\n"); 203 204 /* 205 * setup_cpu may need to be called on the boot cpu. We havent 206 * spun any cpus up but lets be paranoid. 207 */ 208 BUG_ON(boot_cpuid != smp_processor_id()); 209 210 /* Fixup boot cpu */ 211 smp_store_cpu_info(boot_cpuid); 212 cpu_callin_map[boot_cpuid] = 1; 213 214 if (smp_ops) 215 max_cpus = smp_ops->probe(); 216 else 217 max_cpus = 1; 218 219 smp_space_timers(max_cpus); 220 221 for_each_possible_cpu(cpu) 222 if (cpu != boot_cpuid) 223 smp_create_idle(cpu); 224 } 225 226 void __devinit smp_prepare_boot_cpu(void) 227 { 228 BUG_ON(smp_processor_id() != boot_cpuid); 229 230 cpu_set(boot_cpuid, cpu_online_map); 231 #ifdef CONFIG_PPC64 232 paca[boot_cpuid].__current = current; 233 #endif 234 current_set[boot_cpuid] = task_thread_info(current); 235 } 236 237 #ifdef CONFIG_HOTPLUG_CPU 238 /* State of each CPU during hotplug phases */ 239 DEFINE_PER_CPU(int, cpu_state) = { 0 }; 240 241 int generic_cpu_disable(void) 242 { 243 unsigned int cpu = smp_processor_id(); 244 245 if (cpu == boot_cpuid) 246 return -EBUSY; 247 248 cpu_clear(cpu, cpu_online_map); 249 #ifdef CONFIG_PPC64 250 vdso_data->processorCount--; 251 fixup_irqs(cpu_online_map); 252 #endif 253 return 0; 254 } 255 256 int generic_cpu_enable(unsigned int cpu) 257 { 258 /* Do the normal bootup if we haven't 259 * already bootstrapped. */ 260 if (system_state != SYSTEM_RUNNING) 261 return -ENOSYS; 262 263 /* get the target out of it's holding state */ 264 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; 265 smp_wmb(); 266 267 while (!cpu_online(cpu)) 268 cpu_relax(); 269 270 #ifdef CONFIG_PPC64 271 fixup_irqs(cpu_online_map); 272 /* counter the irq disable in fixup_irqs */ 273 local_irq_enable(); 274 #endif 275 return 0; 276 } 277 278 void generic_cpu_die(unsigned int cpu) 279 { 280 int i; 281 282 for (i = 0; i < 100; i++) { 283 smp_rmb(); 284 if (per_cpu(cpu_state, cpu) == CPU_DEAD) 285 return; 286 msleep(100); 287 } 288 printk(KERN_ERR "CPU%d didn't die...\n", cpu); 289 } 290 291 void generic_mach_cpu_die(void) 292 { 293 unsigned int cpu; 294 295 local_irq_disable(); 296 cpu = smp_processor_id(); 297 printk(KERN_DEBUG "CPU%d offline\n", cpu); 298 __get_cpu_var(cpu_state) = CPU_DEAD; 299 smp_wmb(); 300 while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) 301 cpu_relax(); 302 cpu_set(cpu, cpu_online_map); 303 local_irq_enable(); 304 } 305 #endif 306 307 static int __devinit cpu_enable(unsigned int cpu) 308 { 309 if (smp_ops && smp_ops->cpu_enable) 310 return smp_ops->cpu_enable(cpu); 311 312 return -ENOSYS; 313 } 314 315 int __cpuinit __cpu_up(unsigned int cpu) 316 { 317 int c; 318 319 secondary_ti = current_set[cpu]; 320 if (!cpu_enable(cpu)) 321 return 0; 322 323 if (smp_ops == NULL || 324 (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))) 325 return -EINVAL; 326 327 /* Make sure callin-map entry is 0 (can be leftover a CPU 328 * hotplug 329 */ 330 cpu_callin_map[cpu] = 0; 331 332 /* The information for processor bringup must 333 * be written out to main store before we release 334 * the processor. 335 */ 336 smp_mb(); 337 338 /* wake up cpus */ 339 DBG("smp: kicking cpu %d\n", cpu); 340 smp_ops->kick_cpu(cpu); 341 342 /* 343 * wait to see if the cpu made a callin (is actually up). 344 * use this value that I found through experimentation. 345 * -- Cort 346 */ 347 if (system_state < SYSTEM_RUNNING) 348 for (c = 50000; c && !cpu_callin_map[cpu]; c--) 349 udelay(100); 350 #ifdef CONFIG_HOTPLUG_CPU 351 else 352 /* 353 * CPUs can take much longer to come up in the 354 * hotplug case. Wait five seconds. 355 */ 356 for (c = 25; c && !cpu_callin_map[cpu]; c--) { 357 msleep(200); 358 } 359 #endif 360 361 if (!cpu_callin_map[cpu]) { 362 printk("Processor %u is stuck.\n", cpu); 363 return -ENOENT; 364 } 365 366 printk("Processor %u found.\n", cpu); 367 368 if (smp_ops->give_timebase) 369 smp_ops->give_timebase(); 370 371 /* Wait until cpu puts itself in the online map */ 372 while (!cpu_online(cpu)) 373 cpu_relax(); 374 375 return 0; 376 } 377 378 379 /* Activate a secondary processor. */ 380 int __devinit start_secondary(void *unused) 381 { 382 unsigned int cpu = smp_processor_id(); 383 384 atomic_inc(&init_mm.mm_count); 385 current->active_mm = &init_mm; 386 387 smp_store_cpu_info(cpu); 388 set_dec(tb_ticks_per_jiffy); 389 preempt_disable(); 390 cpu_callin_map[cpu] = 1; 391 392 smp_ops->setup_cpu(cpu); 393 if (smp_ops->take_timebase) 394 smp_ops->take_timebase(); 395 396 if (system_state > SYSTEM_BOOTING) 397 snapshot_timebase(); 398 399 secondary_cpu_time_init(); 400 401 ipi_call_lock(); 402 cpu_set(cpu, cpu_online_map); 403 ipi_call_unlock(); 404 405 local_irq_enable(); 406 407 cpu_idle(); 408 return 0; 409 } 410 411 int setup_profiling_timer(unsigned int multiplier) 412 { 413 return 0; 414 } 415 416 void __init smp_cpus_done(unsigned int max_cpus) 417 { 418 cpumask_t old_mask; 419 420 /* We want the setup_cpu() here to be called from CPU 0, but our 421 * init thread may have been "borrowed" by another CPU in the meantime 422 * se we pin us down to CPU 0 for a short while 423 */ 424 old_mask = current->cpus_allowed; 425 set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid)); 426 427 if (smp_ops) 428 smp_ops->setup_cpu(boot_cpuid); 429 430 set_cpus_allowed(current, old_mask); 431 432 snapshot_timebases(); 433 434 dump_numa_cpu_topology(); 435 } 436 437 #ifdef CONFIG_HOTPLUG_CPU 438 int __cpu_disable(void) 439 { 440 if (smp_ops->cpu_disable) 441 return smp_ops->cpu_disable(); 442 443 return -ENOSYS; 444 } 445 446 void __cpu_die(unsigned int cpu) 447 { 448 if (smp_ops->cpu_die) 449 smp_ops->cpu_die(cpu); 450 } 451 #endif 452