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; 66 67 static int parisc_max_cpus = 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 inc_irq_stat(irq_call_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 inc_irq_stat(irq_resched_count); 159 scheduler_ipi(); 160 break; 161 162 case IPI_CALL_FUNC: 163 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 164 generic_smp_call_function_interrupt(); 165 break; 166 167 case IPI_CALL_FUNC_SINGLE: 168 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu); 169 generic_smp_call_function_single_interrupt(); 170 break; 171 172 case IPI_CPU_START: 173 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 174 break; 175 176 case IPI_CPU_STOP: 177 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 178 halt_processor(); 179 break; 180 181 case IPI_CPU_TEST: 182 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 183 break; 184 185 default: 186 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 187 this_cpu, which); 188 return IRQ_NONE; 189 } /* Switch */ 190 /* let in any pending interrupts */ 191 local_irq_enable(); 192 local_irq_disable(); 193 } /* while (ops) */ 194 } 195 return IRQ_HANDLED; 196 } 197 198 199 static inline void 200 ipi_send(int cpu, enum ipi_message_type op) 201 { 202 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu); 203 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 204 unsigned long flags; 205 206 spin_lock_irqsave(lock, flags); 207 p->pending_ipi |= 1 << op; 208 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa); 209 spin_unlock_irqrestore(lock, flags); 210 } 211 212 static void 213 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op) 214 { 215 int cpu; 216 217 for_each_cpu(cpu, mask) 218 ipi_send(cpu, op); 219 } 220 221 static inline void 222 send_IPI_single(int dest_cpu, enum ipi_message_type op) 223 { 224 BUG_ON(dest_cpu == NO_PROC_ID); 225 226 ipi_send(dest_cpu, op); 227 } 228 229 static inline void 230 send_IPI_allbutself(enum ipi_message_type op) 231 { 232 int i; 233 234 for_each_online_cpu(i) { 235 if (i != smp_processor_id()) 236 send_IPI_single(i, op); 237 } 238 } 239 240 241 inline void 242 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 243 244 static inline void 245 smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); } 246 247 void 248 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 249 250 void 251 smp_send_all_nop(void) 252 { 253 send_IPI_allbutself(IPI_NOP); 254 } 255 256 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 257 { 258 send_IPI_mask(mask, IPI_CALL_FUNC); 259 } 260 261 void arch_send_call_function_single_ipi(int cpu) 262 { 263 send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE); 264 } 265 266 /* 267 * Called by secondaries to update state and initialize CPU registers. 268 */ 269 static void __init 270 smp_cpu_init(int cpunum) 271 { 272 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ 273 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 274 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 275 276 /* Set modes and Enable floating point coprocessor */ 277 (void) init_per_cpu(cpunum); 278 279 disable_sr_hashing(); 280 281 mb(); 282 283 /* Well, support 2.4 linux scheme as well. */ 284 if (cpu_online(cpunum)) { 285 extern void machine_halt(void); /* arch/parisc.../process.c */ 286 287 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 288 machine_halt(); 289 } 290 291 notify_cpu_starting(cpunum); 292 293 set_cpu_online(cpunum, true); 294 295 /* Initialise the idle task for this CPU */ 296 atomic_inc(&init_mm.mm_count); 297 current->active_mm = &init_mm; 298 BUG_ON(current->mm); 299 enter_lazy_tlb(&init_mm, current); 300 301 init_IRQ(); /* make sure no IRQs are enabled or pending */ 302 start_cpu_itimer(); 303 } 304 305 306 /* 307 * Slaves start using C here. Indirectly called from smp_slave_stext. 308 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 309 */ 310 void __init smp_callin(void) 311 { 312 int slave_id = cpu_now_booting; 313 314 smp_cpu_init(slave_id); 315 preempt_disable(); 316 317 flush_cache_all_local(); /* start with known state */ 318 flush_tlb_all_local(NULL); 319 320 local_irq_enable(); /* Interrupts have been off until now */ 321 322 cpu_startup_entry(CPUHP_ONLINE); 323 324 /* NOTREACHED */ 325 panic("smp_callin() AAAAaaaaahhhh....\n"); 326 } 327 328 /* 329 * Bring one cpu online. 330 */ 331 int smp_boot_one_cpu(int cpuid, struct task_struct *idle) 332 { 333 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 334 long timeout; 335 336 task_thread_info(idle)->cpu = cpuid; 337 338 /* Let _start know what logical CPU we're booting 339 ** (offset into init_tasks[],cpu_data[]) 340 */ 341 cpu_now_booting = cpuid; 342 343 /* 344 ** boot strap code needs to know the task address since 345 ** it also contains the process stack. 346 */ 347 smp_init_current_idle_task = idle ; 348 mb(); 349 350 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 351 352 /* 353 ** This gets PDC to release the CPU from a very tight loop. 354 ** 355 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 356 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 357 ** is executed after receiving the rendezvous signal (an interrupt to 358 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 359 ** contents of memory are valid." 360 */ 361 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 362 mb(); 363 364 /* 365 * OK, wait a bit for that CPU to finish staggering about. 366 * Slave will set a bit when it reaches smp_cpu_init(). 367 * Once the "monarch CPU" sees the bit change, it can move on. 368 */ 369 for (timeout = 0; timeout < 10000; timeout++) { 370 if(cpu_online(cpuid)) { 371 /* Which implies Slave has started up */ 372 cpu_now_booting = 0; 373 smp_init_current_idle_task = NULL; 374 goto alive ; 375 } 376 udelay(100); 377 barrier(); 378 } 379 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 380 return -1; 381 382 alive: 383 /* Remember the Slave data */ 384 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 385 cpuid, timeout * 100); 386 return 0; 387 } 388 389 void __init smp_prepare_boot_cpu(void) 390 { 391 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 392 393 /* Setup BSP mappings */ 394 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 395 396 set_cpu_online(bootstrap_processor, true); 397 set_cpu_present(bootstrap_processor, true); 398 } 399 400 401 402 /* 403 ** inventory.c:do_inventory() hasn't yet been run and thus we 404 ** don't 'discover' the additional CPUs until later. 405 */ 406 void __init smp_prepare_cpus(unsigned int max_cpus) 407 { 408 int cpu; 409 410 for_each_possible_cpu(cpu) 411 spin_lock_init(&per_cpu(ipi_lock, cpu)); 412 413 init_cpu_present(cpumask_of(0)); 414 415 parisc_max_cpus = max_cpus; 416 if (!max_cpus) 417 printk(KERN_INFO "SMP mode deactivated.\n"); 418 } 419 420 421 void smp_cpus_done(unsigned int cpu_max) 422 { 423 return; 424 } 425 426 427 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 428 { 429 if (cpu != 0 && cpu < parisc_max_cpus) 430 smp_boot_one_cpu(cpu, tidle); 431 432 return cpu_online(cpu) ? 0 : -ENOSYS; 433 } 434 435 #ifdef CONFIG_PROC_FS 436 int __init 437 setup_profiling_timer(unsigned int multiplier) 438 { 439 return -EINVAL; 440 } 441 #endif 442