1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 ** SMP Support 4 ** 5 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com> 6 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com> 7 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org> 8 ** 9 ** Lots of stuff stolen from arch/alpha/kernel/smp.c 10 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^) 11 ** 12 ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work. 13 ** -grant (1/12/2001) 14 ** 15 */ 16 #include <linux/types.h> 17 #include <linux/spinlock.h> 18 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/sched/mm.h> 22 #include <linux/init.h> 23 #include <linux/interrupt.h> 24 #include <linux/smp.h> 25 #include <linux/kernel_stat.h> 26 #include <linux/mm.h> 27 #include <linux/err.h> 28 #include <linux/delay.h> 29 #include <linux/bitops.h> 30 #include <linux/ftrace.h> 31 #include <linux/cpu.h> 32 #include <linux/kgdb.h> 33 34 #include <linux/atomic.h> 35 #include <asm/current.h> 36 #include <asm/delay.h> 37 #include <asm/tlbflush.h> 38 39 #include <asm/io.h> 40 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */ 41 #include <asm/mmu_context.h> 42 #include <asm/page.h> 43 #include <asm/processor.h> 44 #include <asm/ptrace.h> 45 #include <asm/unistd.h> 46 #include <asm/cacheflush.h> 47 48 #undef DEBUG_SMP 49 #ifdef DEBUG_SMP 50 static int smp_debug_lvl = 0; 51 #define smp_debug(lvl, printargs...) \ 52 if (lvl >= smp_debug_lvl) \ 53 printk(printargs); 54 #else 55 #define smp_debug(lvl, ...) do { } while(0) 56 #endif /* DEBUG_SMP */ 57 58 volatile struct task_struct *smp_init_current_idle_task; 59 60 /* track which CPU is booting */ 61 static volatile int cpu_now_booting; 62 63 static int parisc_max_cpus = 1; 64 65 static DEFINE_PER_CPU(spinlock_t, ipi_lock); 66 67 enum ipi_message_type { 68 IPI_NOP=0, 69 IPI_RESCHEDULE=1, 70 IPI_CALL_FUNC, 71 IPI_CPU_START, 72 IPI_CPU_STOP, 73 IPI_CPU_TEST, 74 #ifdef CONFIG_KGDB 75 IPI_ENTER_KGDB, 76 #endif 77 }; 78 79 80 /********** SMP inter processor interrupt and communication routines */ 81 82 #undef PER_CPU_IRQ_REGION 83 #ifdef PER_CPU_IRQ_REGION 84 /* XXX REVISIT Ignore for now. 85 ** *May* need this "hook" to register IPI handler 86 ** once we have perCPU ExtIntr switch tables. 87 */ 88 static void 89 ipi_init(int cpuid) 90 { 91 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 92 93 if(cpu_online(cpuid) ) 94 { 95 switch_to_idle_task(current); 96 } 97 98 return; 99 } 100 #endif 101 102 103 /* 104 ** Yoink this CPU from the runnable list... 105 ** 106 */ 107 static void 108 halt_processor(void) 109 { 110 /* REVISIT : redirect I/O Interrupts to another CPU? */ 111 /* REVISIT : does PM *know* this CPU isn't available? */ 112 set_cpu_online(smp_processor_id(), false); 113 local_irq_disable(); 114 __pdc_cpu_rendezvous(); 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 inc_irq_stat(irq_call_count); 159 generic_smp_call_function_interrupt(); 160 break; 161 162 case IPI_CPU_START: 163 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 164 break; 165 166 case IPI_CPU_STOP: 167 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 168 halt_processor(); 169 break; 170 171 case IPI_CPU_TEST: 172 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 173 break; 174 #ifdef CONFIG_KGDB 175 case IPI_ENTER_KGDB: 176 smp_debug(100, KERN_DEBUG "CPU%d ENTER_KGDB\n", this_cpu); 177 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); 178 break; 179 #endif 180 default: 181 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 182 this_cpu, which); 183 return IRQ_NONE; 184 } /* Switch */ 185 186 /* before doing more, let in any pending interrupts */ 187 if (ops) { 188 local_irq_enable(); 189 local_irq_disable(); 190 } 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 preempt_disable(); 233 for_each_online_cpu(i) { 234 if (i != smp_processor_id()) 235 send_IPI_single(i, op); 236 } 237 preempt_enable(); 238 } 239 240 #ifdef CONFIG_KGDB 241 void kgdb_roundup_cpus(void) 242 { 243 send_IPI_allbutself(IPI_ENTER_KGDB); 244 } 245 #endif 246 247 inline void 248 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 249 250 void 251 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 252 253 void 254 smp_send_all_nop(void) 255 { 256 send_IPI_allbutself(IPI_NOP); 257 } 258 259 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 260 { 261 send_IPI_mask(mask, IPI_CALL_FUNC); 262 } 263 264 void arch_send_call_function_single_ipi(int cpu) 265 { 266 send_IPI_single(cpu, IPI_CALL_FUNC); 267 } 268 269 /* 270 * Called by secondaries to update state and initialize CPU registers. 271 */ 272 static void __init 273 smp_cpu_init(int cpunum) 274 { 275 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 276 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 277 278 /* Set modes and Enable floating point coprocessor */ 279 init_per_cpu(cpunum); 280 281 disable_sr_hashing(); 282 283 mb(); 284 285 /* Well, support 2.4 linux scheme as well. */ 286 if (cpu_online(cpunum)) { 287 extern void machine_halt(void); /* arch/parisc.../process.c */ 288 289 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 290 machine_halt(); 291 } 292 293 notify_cpu_starting(cpunum); 294 295 set_cpu_online(cpunum, true); 296 297 /* Initialise the idle task for this CPU */ 298 mmgrab(&init_mm); 299 current->active_mm = &init_mm; 300 BUG_ON(current->mm); 301 enter_lazy_tlb(&init_mm, current); 302 303 init_IRQ(); /* make sure no IRQs are enabled or pending */ 304 start_cpu_itimer(); 305 } 306 307 308 /* 309 * Slaves start using C here. Indirectly called from smp_slave_stext. 310 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 311 */ 312 void __init smp_callin(unsigned long pdce_proc) 313 { 314 int slave_id = cpu_now_booting; 315 316 #ifdef CONFIG_64BIT 317 WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32 318 | PAGE0->mem_pdc) != pdce_proc); 319 #endif 320 321 smp_cpu_init(slave_id); 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_startup_entry(CPUHP_AP_ONLINE_IDLE); 329 330 /* NOTREACHED */ 331 panic("smp_callin() AAAAaaaaahhhh....\n"); 332 } 333 334 /* 335 * Bring one cpu online. 336 */ 337 int smp_boot_one_cpu(int cpuid, struct task_struct *idle) 338 { 339 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 340 long timeout; 341 342 idle->cpu = cpuid; 343 344 /* Let _start know what logical CPU we're booting 345 ** (offset into init_tasks[],cpu_data[]) 346 */ 347 cpu_now_booting = cpuid; 348 349 /* 350 ** boot strap code needs to know the task address since 351 ** it also contains the process stack. 352 */ 353 smp_init_current_idle_task = idle ; 354 mb(); 355 356 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 357 358 /* 359 ** This gets PDC to release the CPU from a very tight loop. 360 ** 361 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 362 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 363 ** is executed after receiving the rendezvous signal (an interrupt to 364 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 365 ** contents of memory are valid." 366 */ 367 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 368 mb(); 369 370 /* 371 * OK, wait a bit for that CPU to finish staggering about. 372 * Slave will set a bit when it reaches smp_cpu_init(). 373 * Once the "monarch CPU" sees the bit change, it can move on. 374 */ 375 for (timeout = 0; timeout < 10000; timeout++) { 376 if(cpu_online(cpuid)) { 377 /* Which implies Slave has started up */ 378 cpu_now_booting = 0; 379 smp_init_current_idle_task = NULL; 380 goto alive ; 381 } 382 udelay(100); 383 barrier(); 384 } 385 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 386 return -1; 387 388 alive: 389 /* Remember the Slave data */ 390 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 391 cpuid, timeout * 100); 392 return 0; 393 } 394 395 void __init smp_prepare_boot_cpu(void) 396 { 397 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 398 399 /* Setup BSP mappings */ 400 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 401 402 set_cpu_online(bootstrap_processor, true); 403 set_cpu_present(bootstrap_processor, true); 404 } 405 406 407 408 /* 409 ** inventory.c:do_inventory() hasn't yet been run and thus we 410 ** don't 'discover' the additional CPUs until later. 411 */ 412 void __init smp_prepare_cpus(unsigned int max_cpus) 413 { 414 int cpu; 415 416 for_each_possible_cpu(cpu) 417 spin_lock_init(&per_cpu(ipi_lock, cpu)); 418 419 init_cpu_present(cpumask_of(0)); 420 421 parisc_max_cpus = max_cpus; 422 if (!max_cpus) 423 printk(KERN_INFO "SMP mode deactivated.\n"); 424 } 425 426 427 void smp_cpus_done(unsigned int cpu_max) 428 { 429 return; 430 } 431 432 433 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 434 { 435 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle)) 436 return -ENOSYS; 437 438 return cpu_online(cpu) ? 0 : -ENOSYS; 439 } 440 441 #ifdef CONFIG_PROC_FS 442 int setup_profiling_timer(unsigned int multiplier) 443 { 444 return -EINVAL; 445 } 446 #endif 447