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