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