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 #include <linux/cpu.h> 35 36 #include <linux/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, ...) do { } while(0) 60 #endif /* DEBUG_SMP */ 61 62 volatile struct task_struct *smp_init_current_idle_task; 63 64 /* track which CPU is booting */ 65 static volatile int cpu_now_booting __cpuinitdata; 66 67 static int parisc_max_cpus __cpuinitdata = 1; 68 69 static DEFINE_PER_CPU(spinlock_t, ipi_lock); 70 71 enum 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 86 /* XXX REVISIT Ignore for now. 87 ** *May* need this "hook" to register IPI handler 88 ** once we have perCPU ExtIntr switch tables. 89 */ 90 static void 91 ipi_init(int cpuid) 92 { 93 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 94 95 if(cpu_online(cpuid) ) 96 { 97 switch_to_idle_task(current); 98 } 99 100 return; 101 } 102 #endif 103 104 105 /* 106 ** Yoink this CPU from the runnable list... 107 ** 108 */ 109 static void 110 halt_processor(void) 111 { 112 /* REVISIT : redirect I/O Interrupts to another CPU? */ 113 /* REVISIT : does PM *know* this CPU isn't available? */ 114 set_cpu_online(smp_processor_id(), false); 115 local_irq_disable(); 116 for (;;) 117 ; 118 } 119 120 121 irqreturn_t __irq_entry 122 ipi_interrupt(int irq, void *dev_id) 123 { 124 int this_cpu = smp_processor_id(); 125 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu); 126 unsigned long ops; 127 unsigned long flags; 128 129 /* Count this now; we may make a call that never returns. */ 130 p->ipi_count++; 131 132 mb(); /* Order interrupt and bit testing. */ 133 134 for (;;) { 135 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 136 spin_lock_irqsave(lock, flags); 137 ops = p->pending_ipi; 138 p->pending_ipi = 0; 139 spin_unlock_irqrestore(lock, flags); 140 141 mb(); /* Order bit clearing and data access. */ 142 143 if (!ops) 144 break; 145 146 while (ops) { 147 unsigned long which = ffz(~ops); 148 149 ops &= ~(1 << which); 150 151 switch (which) { 152 case IPI_NOP: 153 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 154 break; 155 156 case IPI_RESCHEDULE: 157 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 158 scheduler_ipi(); 159 break; 160 161 case IPI_CALL_FUNC: 162 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 163 generic_smp_call_function_interrupt(); 164 break; 165 166 case IPI_CALL_FUNC_SINGLE: 167 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu); 168 generic_smp_call_function_single_interrupt(); 169 break; 170 171 case IPI_CPU_START: 172 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 173 break; 174 175 case IPI_CPU_STOP: 176 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 177 halt_processor(); 178 break; 179 180 case IPI_CPU_TEST: 181 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 182 break; 183 184 default: 185 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 186 this_cpu, which); 187 return IRQ_NONE; 188 } /* Switch */ 189 /* let in any pending interrupts */ 190 local_irq_enable(); 191 local_irq_disable(); 192 } /* while (ops) */ 193 } 194 return IRQ_HANDLED; 195 } 196 197 198 static inline void 199 ipi_send(int cpu, enum ipi_message_type op) 200 { 201 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu); 202 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 203 unsigned long flags; 204 205 spin_lock_irqsave(lock, flags); 206 p->pending_ipi |= 1 << op; 207 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa); 208 spin_unlock_irqrestore(lock, flags); 209 } 210 211 static void 212 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op) 213 { 214 int cpu; 215 216 for_each_cpu(cpu, mask) 217 ipi_send(cpu, op); 218 } 219 220 static inline void 221 send_IPI_single(int dest_cpu, enum ipi_message_type op) 222 { 223 BUG_ON(dest_cpu == NO_PROC_ID); 224 225 ipi_send(dest_cpu, op); 226 } 227 228 static inline void 229 send_IPI_allbutself(enum ipi_message_type op) 230 { 231 int i; 232 233 for_each_online_cpu(i) { 234 if (i != smp_processor_id()) 235 send_IPI_single(i, op); 236 } 237 } 238 239 240 inline void 241 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 242 243 static inline void 244 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); } 245 246 void 247 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 248 249 void 250 smp_send_all_nop(void) 251 { 252 send_IPI_allbutself(IPI_NOP); 253 } 254 255 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 256 { 257 send_IPI_mask(mask, IPI_CALL_FUNC); 258 } 259 260 void arch_send_call_function_single_ipi(int cpu) 261 { 262 send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE); 263 } 264 265 /* 266 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu() 267 * as we want to ensure all TLB's flushed before proceeding. 268 */ 269 270 void 271 smp_flush_tlb_all(void) 272 { 273 on_each_cpu(flush_tlb_all_local, NULL, 1); 274 } 275 276 /* 277 * Called by secondaries to update state and initialize CPU registers. 278 */ 279 static void __init 280 smp_cpu_init(int cpunum) 281 { 282 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ 283 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 284 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 285 286 /* Set modes and Enable floating point coprocessor */ 287 (void) init_per_cpu(cpunum); 288 289 disable_sr_hashing(); 290 291 mb(); 292 293 /* Well, support 2.4 linux scheme as well. */ 294 if (cpu_online(cpunum)) { 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 } 300 301 notify_cpu_starting(cpunum); 302 303 ipi_call_lock(); 304 set_cpu_online(cpunum, true); 305 ipi_call_unlock(); 306 307 /* Initialise the idle task for this CPU */ 308 atomic_inc(&init_mm.mm_count); 309 current->active_mm = &init_mm; 310 BUG_ON(current->mm); 311 enter_lazy_tlb(&init_mm, current); 312 313 init_IRQ(); /* make sure no IRQs are enabled or pending */ 314 start_cpu_itimer(); 315 } 316 317 318 /* 319 * Slaves start using C here. Indirectly called from smp_slave_stext. 320 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 321 */ 322 void __init smp_callin(void) 323 { 324 int slave_id = cpu_now_booting; 325 326 smp_cpu_init(slave_id); 327 preempt_disable(); 328 329 flush_cache_all_local(); /* start with known state */ 330 flush_tlb_all_local(NULL); 331 332 local_irq_enable(); /* Interrupts have been off until now */ 333 334 cpu_idle(); /* Wait for timer to schedule some work */ 335 336 /* NOTREACHED */ 337 panic("smp_callin() AAAAaaaaahhhh....\n"); 338 } 339 340 /* 341 * Bring one cpu online. 342 */ 343 int __cpuinit smp_boot_one_cpu(int cpuid) 344 { 345 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 346 struct task_struct *idle; 347 long timeout; 348 349 /* 350 * Create an idle task for this CPU. Note the address wed* give 351 * to kernel_thread is irrelevant -- it's going to start 352 * where OS_BOOT_RENDEVZ vector in SAL says to start. But 353 * this gets all the other task-y sort of data structures set 354 * up like we wish. We need to pull the just created idle task 355 * off the run queue and stuff it into the init_tasks[] array. 356 * Sheesh . . . 357 */ 358 359 idle = fork_idle(cpuid); 360 if (IS_ERR(idle)) 361 panic("SMP: fork failed for CPU:%d", cpuid); 362 363 task_thread_info(idle)->cpu = cpuid; 364 365 /* Let _start know what logical CPU we're booting 366 ** (offset into init_tasks[],cpu_data[]) 367 */ 368 cpu_now_booting = cpuid; 369 370 /* 371 ** boot strap code needs to know the task address since 372 ** it also contains the process stack. 373 */ 374 smp_init_current_idle_task = idle ; 375 mb(); 376 377 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 378 379 /* 380 ** This gets PDC to release the CPU from a very tight loop. 381 ** 382 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 383 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 384 ** is executed after receiving the rendezvous signal (an interrupt to 385 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 386 ** contents of memory are valid." 387 */ 388 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 389 mb(); 390 391 /* 392 * OK, wait a bit for that CPU to finish staggering about. 393 * Slave will set a bit when it reaches smp_cpu_init(). 394 * Once the "monarch CPU" sees the bit change, it can move on. 395 */ 396 for (timeout = 0; timeout < 10000; timeout++) { 397 if(cpu_online(cpuid)) { 398 /* Which implies Slave has started up */ 399 cpu_now_booting = 0; 400 smp_init_current_idle_task = NULL; 401 goto alive ; 402 } 403 udelay(100); 404 barrier(); 405 } 406 407 put_task_struct(idle); 408 idle = NULL; 409 410 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 411 return -1; 412 413 alive: 414 /* Remember the Slave data */ 415 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 416 cpuid, timeout * 100); 417 return 0; 418 } 419 420 void __init smp_prepare_boot_cpu(void) 421 { 422 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 423 424 /* Setup BSP mappings */ 425 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 426 427 set_cpu_online(bootstrap_processor, true); 428 set_cpu_present(bootstrap_processor, true); 429 } 430 431 432 433 /* 434 ** inventory.c:do_inventory() hasn't yet been run and thus we 435 ** don't 'discover' the additional CPUs until later. 436 */ 437 void __init smp_prepare_cpus(unsigned int max_cpus) 438 { 439 int cpu; 440 441 for_each_possible_cpu(cpu) 442 spin_lock_init(&per_cpu(ipi_lock, cpu)); 443 444 init_cpu_present(cpumask_of(0)); 445 446 parisc_max_cpus = max_cpus; 447 if (!max_cpus) 448 printk(KERN_INFO "SMP mode deactivated.\n"); 449 } 450 451 452 void smp_cpus_done(unsigned int cpu_max) 453 { 454 return; 455 } 456 457 458 int __cpuinit __cpu_up(unsigned int cpu) 459 { 460 if (cpu != 0 && cpu < parisc_max_cpus) 461 smp_boot_one_cpu(cpu); 462 463 return cpu_online(cpu) ? 0 : -ENOSYS; 464 } 465 466 #ifdef CONFIG_PROC_FS 467 int __init 468 setup_profiling_timer(unsigned int multiplier) 469 { 470 return -EINVAL; 471 } 472 #endif 473