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 for (;;) { 129 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 130 spin_lock_irqsave(lock, flags); 131 ops = p->pending_ipi; 132 p->pending_ipi = 0; 133 spin_unlock_irqrestore(lock, flags); 134 135 mb(); /* Order bit clearing and data access. */ 136 137 if (!ops) 138 break; 139 140 while (ops) { 141 unsigned long which = ffz(~ops); 142 143 ops &= ~(1 << which); 144 145 switch (which) { 146 case IPI_NOP: 147 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 148 break; 149 150 case IPI_RESCHEDULE: 151 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 152 inc_irq_stat(irq_resched_count); 153 scheduler_ipi(); 154 break; 155 156 case IPI_CALL_FUNC: 157 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 158 generic_smp_call_function_interrupt(); 159 break; 160 161 case IPI_CPU_START: 162 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 163 break; 164 165 case IPI_CPU_STOP: 166 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 167 halt_processor(); 168 break; 169 170 case IPI_CPU_TEST: 171 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 172 break; 173 174 default: 175 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 176 this_cpu, which); 177 return IRQ_NONE; 178 } /* Switch */ 179 /* let in any pending interrupts */ 180 local_irq_enable(); 181 local_irq_disable(); 182 } /* while (ops) */ 183 } 184 return IRQ_HANDLED; 185 } 186 187 188 static inline void 189 ipi_send(int cpu, enum ipi_message_type op) 190 { 191 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu); 192 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 193 unsigned long flags; 194 195 spin_lock_irqsave(lock, flags); 196 p->pending_ipi |= 1 << op; 197 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa); 198 spin_unlock_irqrestore(lock, flags); 199 } 200 201 static void 202 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op) 203 { 204 int cpu; 205 206 for_each_cpu(cpu, mask) 207 ipi_send(cpu, op); 208 } 209 210 static inline void 211 send_IPI_single(int dest_cpu, enum ipi_message_type op) 212 { 213 BUG_ON(dest_cpu == NO_PROC_ID); 214 215 ipi_send(dest_cpu, op); 216 } 217 218 static inline void 219 send_IPI_allbutself(enum ipi_message_type op) 220 { 221 int i; 222 223 for_each_online_cpu(i) { 224 if (i != smp_processor_id()) 225 send_IPI_single(i, op); 226 } 227 } 228 229 230 inline void 231 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 232 233 void 234 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 235 236 void 237 smp_send_all_nop(void) 238 { 239 send_IPI_allbutself(IPI_NOP); 240 } 241 242 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 243 { 244 send_IPI_mask(mask, IPI_CALL_FUNC); 245 } 246 247 void arch_send_call_function_single_ipi(int cpu) 248 { 249 send_IPI_single(cpu, IPI_CALL_FUNC); 250 } 251 252 /* 253 * Called by secondaries to update state and initialize CPU registers. 254 */ 255 static void __init 256 smp_cpu_init(int cpunum) 257 { 258 extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ 259 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 260 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 261 262 /* Set modes and Enable floating point coprocessor */ 263 (void) init_per_cpu(cpunum); 264 265 disable_sr_hashing(); 266 267 mb(); 268 269 /* Well, support 2.4 linux scheme as well. */ 270 if (cpu_online(cpunum)) { 271 extern void machine_halt(void); /* arch/parisc.../process.c */ 272 273 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 274 machine_halt(); 275 } 276 277 notify_cpu_starting(cpunum); 278 279 set_cpu_online(cpunum, true); 280 281 /* Initialise the idle task for this CPU */ 282 atomic_inc(&init_mm.mm_count); 283 current->active_mm = &init_mm; 284 BUG_ON(current->mm); 285 enter_lazy_tlb(&init_mm, current); 286 287 init_IRQ(); /* make sure no IRQs are enabled or pending */ 288 start_cpu_itimer(); 289 } 290 291 292 /* 293 * Slaves start using C here. Indirectly called from smp_slave_stext. 294 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 295 */ 296 void __init smp_callin(void) 297 { 298 int slave_id = cpu_now_booting; 299 300 smp_cpu_init(slave_id); 301 preempt_disable(); 302 303 flush_cache_all_local(); /* start with known state */ 304 flush_tlb_all_local(NULL); 305 306 local_irq_enable(); /* Interrupts have been off until now */ 307 308 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 309 310 /* NOTREACHED */ 311 panic("smp_callin() AAAAaaaaahhhh....\n"); 312 } 313 314 /* 315 * Bring one cpu online. 316 */ 317 int smp_boot_one_cpu(int cpuid, struct task_struct *idle) 318 { 319 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 320 long timeout; 321 322 task_thread_info(idle)->cpu = cpuid; 323 324 /* Let _start know what logical CPU we're booting 325 ** (offset into init_tasks[],cpu_data[]) 326 */ 327 cpu_now_booting = cpuid; 328 329 /* 330 ** boot strap code needs to know the task address since 331 ** it also contains the process stack. 332 */ 333 smp_init_current_idle_task = idle ; 334 mb(); 335 336 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 337 338 /* 339 ** This gets PDC to release the CPU from a very tight loop. 340 ** 341 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 342 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 343 ** is executed after receiving the rendezvous signal (an interrupt to 344 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 345 ** contents of memory are valid." 346 */ 347 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 348 mb(); 349 350 /* 351 * OK, wait a bit for that CPU to finish staggering about. 352 * Slave will set a bit when it reaches smp_cpu_init(). 353 * Once the "monarch CPU" sees the bit change, it can move on. 354 */ 355 for (timeout = 0; timeout < 10000; timeout++) { 356 if(cpu_online(cpuid)) { 357 /* Which implies Slave has started up */ 358 cpu_now_booting = 0; 359 smp_init_current_idle_task = NULL; 360 goto alive ; 361 } 362 udelay(100); 363 barrier(); 364 } 365 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 366 return -1; 367 368 alive: 369 /* Remember the Slave data */ 370 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 371 cpuid, timeout * 100); 372 return 0; 373 } 374 375 void __init smp_prepare_boot_cpu(void) 376 { 377 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 378 379 /* Setup BSP mappings */ 380 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 381 382 set_cpu_online(bootstrap_processor, true); 383 set_cpu_present(bootstrap_processor, true); 384 } 385 386 387 388 /* 389 ** inventory.c:do_inventory() hasn't yet been run and thus we 390 ** don't 'discover' the additional CPUs until later. 391 */ 392 void __init smp_prepare_cpus(unsigned int max_cpus) 393 { 394 int cpu; 395 396 for_each_possible_cpu(cpu) 397 spin_lock_init(&per_cpu(ipi_lock, cpu)); 398 399 init_cpu_present(cpumask_of(0)); 400 401 parisc_max_cpus = max_cpus; 402 if (!max_cpus) 403 printk(KERN_INFO "SMP mode deactivated.\n"); 404 } 405 406 407 void smp_cpus_done(unsigned int cpu_max) 408 { 409 return; 410 } 411 412 413 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 414 { 415 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle)) 416 return -ENOSYS; 417 418 return cpu_online(cpu) ? 0 : -ENOSYS; 419 } 420 421 #ifdef CONFIG_PROC_FS 422 int __init 423 setup_profiling_timer(unsigned int multiplier) 424 { 425 return -EINVAL; 426 } 427 #endif 428