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 #include <linux/ftrace.h> 35 36 #include <asm/system.h> 37 #include <asm/atomic.h> 38 #include <asm/current.h> 39 #include <asm/delay.h> 40 #include <asm/tlbflush.h> 41 42 #include <asm/io.h> 43 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */ 44 #include <asm/mmu_context.h> 45 #include <asm/page.h> 46 #include <asm/pgtable.h> 47 #include <asm/pgalloc.h> 48 #include <asm/processor.h> 49 #include <asm/ptrace.h> 50 #include <asm/unistd.h> 51 #include <asm/cacheflush.h> 52 53 #undef DEBUG_SMP 54 #ifdef DEBUG_SMP 55 static int smp_debug_lvl = 0; 56 #define smp_debug(lvl, printargs...) \ 57 if (lvl >= smp_debug_lvl) \ 58 printk(printargs); 59 #else 60 #define smp_debug(lvl, ...) do { } while(0) 61 #endif /* DEBUG_SMP */ 62 63 DEFINE_SPINLOCK(smp_lock); 64 65 volatile struct task_struct *smp_init_current_idle_task; 66 67 /* track which CPU is booting */ 68 static volatile int cpu_now_booting __cpuinitdata; 69 70 static int parisc_max_cpus __cpuinitdata = 1; 71 72 DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED; 73 74 enum ipi_message_type { 75 IPI_NOP=0, 76 IPI_RESCHEDULE=1, 77 IPI_CALL_FUNC, 78 IPI_CALL_FUNC_SINGLE, 79 IPI_CPU_START, 80 IPI_CPU_STOP, 81 IPI_CPU_TEST 82 }; 83 84 85 /********** SMP inter processor interrupt and communication routines */ 86 87 #undef PER_CPU_IRQ_REGION 88 #ifdef PER_CPU_IRQ_REGION 89 /* XXX REVISIT Ignore for now. 90 ** *May* need this "hook" to register IPI handler 91 ** once we have perCPU ExtIntr switch tables. 92 */ 93 static void 94 ipi_init(int cpuid) 95 { 96 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 97 98 if(cpu_online(cpuid) ) 99 { 100 switch_to_idle_task(current); 101 } 102 103 return; 104 } 105 #endif 106 107 108 /* 109 ** Yoink this CPU from the runnable list... 110 ** 111 */ 112 static void 113 halt_processor(void) 114 { 115 /* REVISIT : redirect I/O Interrupts to another CPU? */ 116 /* REVISIT : does PM *know* this CPU isn't available? */ 117 set_cpu_online(smp_processor_id(), false); 118 local_irq_disable(); 119 for (;;) 120 ; 121 } 122 123 124 irqreturn_t __irq_entry 125 ipi_interrupt(int irq, void *dev_id) 126 { 127 int this_cpu = smp_processor_id(); 128 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu); 129 unsigned long ops; 130 unsigned long flags; 131 132 /* Count this now; we may make a call that never returns. */ 133 p->ipi_count++; 134 135 mb(); /* Order interrupt and bit testing. */ 136 137 for (;;) { 138 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 139 spin_lock_irqsave(lock, flags); 140 ops = p->pending_ipi; 141 p->pending_ipi = 0; 142 spin_unlock_irqrestore(lock, flags); 143 144 mb(); /* Order bit clearing and data access. */ 145 146 if (!ops) 147 break; 148 149 while (ops) { 150 unsigned long which = ffz(~ops); 151 152 ops &= ~(1 << which); 153 154 switch (which) { 155 case IPI_NOP: 156 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 157 break; 158 159 case IPI_RESCHEDULE: 160 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 161 /* 162 * Reschedule callback. Everything to be 163 * done is done by the interrupt return path. 164 */ 165 break; 166 167 case IPI_CALL_FUNC: 168 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 169 generic_smp_call_function_interrupt(); 170 break; 171 172 case IPI_CALL_FUNC_SINGLE: 173 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu); 174 generic_smp_call_function_single_interrupt(); 175 break; 176 177 case IPI_CPU_START: 178 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 179 break; 180 181 case IPI_CPU_STOP: 182 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 183 halt_processor(); 184 break; 185 186 case IPI_CPU_TEST: 187 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 188 break; 189 190 default: 191 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 192 this_cpu, which); 193 return IRQ_NONE; 194 } /* Switch */ 195 /* let in any pending interrupts */ 196 local_irq_enable(); 197 local_irq_disable(); 198 } /* while (ops) */ 199 } 200 return IRQ_HANDLED; 201 } 202 203 204 static inline void 205 ipi_send(int cpu, enum ipi_message_type op) 206 { 207 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu); 208 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 209 unsigned long flags; 210 211 spin_lock_irqsave(lock, flags); 212 p->pending_ipi |= 1 << op; 213 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa); 214 spin_unlock_irqrestore(lock, flags); 215 } 216 217 static void 218 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op) 219 { 220 int cpu; 221 222 for_each_cpu(cpu, mask) 223 ipi_send(cpu, op); 224 } 225 226 static inline void 227 send_IPI_single(int dest_cpu, enum ipi_message_type op) 228 { 229 BUG_ON(dest_cpu == NO_PROC_ID); 230 231 ipi_send(dest_cpu, op); 232 } 233 234 static inline void 235 send_IPI_allbutself(enum ipi_message_type op) 236 { 237 int i; 238 239 for_each_online_cpu(i) { 240 if (i != smp_processor_id()) 241 send_IPI_single(i, op); 242 } 243 } 244 245 246 inline void 247 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 248 249 static inline void 250 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); } 251 252 void 253 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 254 255 void 256 smp_send_all_nop(void) 257 { 258 send_IPI_allbutself(IPI_NOP); 259 } 260 261 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 262 { 263 send_IPI_mask(mask, IPI_CALL_FUNC); 264 } 265 266 void arch_send_call_function_single_ipi(int cpu) 267 { 268 send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE); 269 } 270 271 /* 272 * Flush all other CPU's tlb and then mine. Do this with on_each_cpu() 273 * as we want to ensure all TLB's flushed before proceeding. 274 */ 275 276 void 277 smp_flush_tlb_all(void) 278 { 279 on_each_cpu(flush_tlb_all_local, NULL, 1); 280 } 281 282 /* 283 * Called by secondaries to update state and initialize CPU registers. 284 */ 285 static void __init 286 smp_cpu_init(int cpunum) 287 { 288 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ 289 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 290 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 291 292 /* Set modes and Enable floating point coprocessor */ 293 (void) init_per_cpu(cpunum); 294 295 disable_sr_hashing(); 296 297 mb(); 298 299 /* Well, support 2.4 linux scheme as well. */ 300 if (cpu_isset(cpunum, cpu_online_map)) 301 { 302 extern void machine_halt(void); /* arch/parisc.../process.c */ 303 304 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 305 machine_halt(); 306 } 307 set_cpu_online(cpunum, true); 308 309 /* Initialise the idle task for this CPU */ 310 atomic_inc(&init_mm.mm_count); 311 current->active_mm = &init_mm; 312 BUG_ON(current->mm); 313 enter_lazy_tlb(&init_mm, current); 314 315 init_IRQ(); /* make sure no IRQs are enabled or pending */ 316 start_cpu_itimer(); 317 } 318 319 320 /* 321 * Slaves start using C here. Indirectly called from smp_slave_stext. 322 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 323 */ 324 void __init smp_callin(void) 325 { 326 int slave_id = cpu_now_booting; 327 328 smp_cpu_init(slave_id); 329 preempt_disable(); 330 331 flush_cache_all_local(); /* start with known state */ 332 flush_tlb_all_local(NULL); 333 334 local_irq_enable(); /* Interrupts have been off until now */ 335 336 cpu_idle(); /* Wait for timer to schedule some work */ 337 338 /* NOTREACHED */ 339 panic("smp_callin() AAAAaaaaahhhh....\n"); 340 } 341 342 /* 343 * Bring one cpu online. 344 */ 345 int __cpuinit smp_boot_one_cpu(int cpuid) 346 { 347 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 348 struct task_struct *idle; 349 long timeout; 350 351 /* 352 * Create an idle task for this CPU. Note the address wed* give 353 * to kernel_thread is irrelevant -- it's going to start 354 * where OS_BOOT_RENDEVZ vector in SAL says to start. But 355 * this gets all the other task-y sort of data structures set 356 * up like we wish. We need to pull the just created idle task 357 * off the run queue and stuff it into the init_tasks[] array. 358 * Sheesh . . . 359 */ 360 361 idle = fork_idle(cpuid); 362 if (IS_ERR(idle)) 363 panic("SMP: fork failed for CPU:%d", cpuid); 364 365 task_thread_info(idle)->cpu = cpuid; 366 367 /* Let _start know what logical CPU we're booting 368 ** (offset into init_tasks[],cpu_data[]) 369 */ 370 cpu_now_booting = cpuid; 371 372 /* 373 ** boot strap code needs to know the task address since 374 ** it also contains the process stack. 375 */ 376 smp_init_current_idle_task = idle ; 377 mb(); 378 379 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 380 381 /* 382 ** This gets PDC to release the CPU from a very tight loop. 383 ** 384 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 385 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 386 ** is executed after receiving the rendezvous signal (an interrupt to 387 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 388 ** contents of memory are valid." 389 */ 390 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 391 mb(); 392 393 /* 394 * OK, wait a bit for that CPU to finish staggering about. 395 * Slave will set a bit when it reaches smp_cpu_init(). 396 * Once the "monarch CPU" sees the bit change, it can move on. 397 */ 398 for (timeout = 0; timeout < 10000; timeout++) { 399 if(cpu_online(cpuid)) { 400 /* Which implies Slave has started up */ 401 cpu_now_booting = 0; 402 smp_init_current_idle_task = NULL; 403 goto alive ; 404 } 405 udelay(100); 406 barrier(); 407 } 408 409 put_task_struct(idle); 410 idle = NULL; 411 412 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 413 return -1; 414 415 alive: 416 /* Remember the Slave data */ 417 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 418 cpuid, timeout * 100); 419 return 0; 420 } 421 422 void __init smp_prepare_boot_cpu(void) 423 { 424 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 425 426 /* Setup BSP mappings */ 427 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 428 429 set_cpu_online(bootstrap_processor, true); 430 set_cpu_present(bootstrap_processor, true); 431 } 432 433 434 435 /* 436 ** inventory.c:do_inventory() hasn't yet been run and thus we 437 ** don't 'discover' the additional CPUs until later. 438 */ 439 void __init smp_prepare_cpus(unsigned int max_cpus) 440 { 441 init_cpu_present(cpumask_of(0)); 442 443 parisc_max_cpus = max_cpus; 444 if (!max_cpus) 445 printk(KERN_INFO "SMP mode deactivated.\n"); 446 } 447 448 449 void smp_cpus_done(unsigned int cpu_max) 450 { 451 return; 452 } 453 454 455 int __cpuinit __cpu_up(unsigned int cpu) 456 { 457 if (cpu != 0 && cpu < parisc_max_cpus) 458 smp_boot_one_cpu(cpu); 459 460 return cpu_online(cpu) ? 0 : -ENOSYS; 461 } 462 463 #ifdef CONFIG_PROC_FS 464 int __init 465 setup_profiling_timer(unsigned int multiplier) 466 { 467 return -EINVAL; 468 } 469 #endif 470