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 33 #include <linux/atomic.h> 34 #include <asm/current.h> 35 #include <asm/delay.h> 36 #include <asm/tlbflush.h> 37 38 #include <asm/io.h> 39 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */ 40 #include <asm/mmu_context.h> 41 #include <asm/page.h> 42 #include <asm/processor.h> 43 #include <asm/ptrace.h> 44 #include <asm/unistd.h> 45 #include <asm/cacheflush.h> 46 47 #undef DEBUG_SMP 48 #ifdef DEBUG_SMP 49 static int smp_debug_lvl = 0; 50 #define smp_debug(lvl, printargs...) \ 51 if (lvl >= smp_debug_lvl) \ 52 printk(printargs); 53 #else 54 #define smp_debug(lvl, ...) do { } while(0) 55 #endif /* DEBUG_SMP */ 56 57 volatile struct task_struct *smp_init_current_idle_task; 58 59 /* track which CPU is booting */ 60 static volatile int cpu_now_booting; 61 62 static int parisc_max_cpus = 1; 63 64 static DEFINE_PER_CPU(spinlock_t, ipi_lock); 65 66 enum ipi_message_type { 67 IPI_NOP=0, 68 IPI_RESCHEDULE=1, 69 IPI_CALL_FUNC, 70 IPI_CPU_START, 71 IPI_CPU_STOP, 72 IPI_CPU_TEST 73 }; 74 75 76 /********** SMP inter processor interrupt and communication routines */ 77 78 #undef PER_CPU_IRQ_REGION 79 #ifdef PER_CPU_IRQ_REGION 80 /* XXX REVISIT Ignore for now. 81 ** *May* need this "hook" to register IPI handler 82 ** once we have perCPU ExtIntr switch tables. 83 */ 84 static void 85 ipi_init(int cpuid) 86 { 87 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 88 89 if(cpu_online(cpuid) ) 90 { 91 switch_to_idle_task(current); 92 } 93 94 return; 95 } 96 #endif 97 98 99 /* 100 ** Yoink this CPU from the runnable list... 101 ** 102 */ 103 static void 104 halt_processor(void) 105 { 106 /* REVISIT : redirect I/O Interrupts to another CPU? */ 107 /* REVISIT : does PM *know* this CPU isn't available? */ 108 set_cpu_online(smp_processor_id(), false); 109 local_irq_disable(); 110 __pdc_cpu_rendezvous(); 111 for (;;) 112 ; 113 } 114 115 116 irqreturn_t __irq_entry 117 ipi_interrupt(int irq, void *dev_id) 118 { 119 int this_cpu = smp_processor_id(); 120 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu); 121 unsigned long ops; 122 unsigned long flags; 123 124 for (;;) { 125 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 126 spin_lock_irqsave(lock, flags); 127 ops = p->pending_ipi; 128 p->pending_ipi = 0; 129 spin_unlock_irqrestore(lock, flags); 130 131 mb(); /* Order bit clearing and data access. */ 132 133 if (!ops) 134 break; 135 136 while (ops) { 137 unsigned long which = ffz(~ops); 138 139 ops &= ~(1 << which); 140 141 switch (which) { 142 case IPI_NOP: 143 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 144 break; 145 146 case IPI_RESCHEDULE: 147 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 148 inc_irq_stat(irq_resched_count); 149 scheduler_ipi(); 150 break; 151 152 case IPI_CALL_FUNC: 153 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 154 inc_irq_stat(irq_call_count); 155 generic_smp_call_function_interrupt(); 156 break; 157 158 case IPI_CPU_START: 159 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 160 break; 161 162 case IPI_CPU_STOP: 163 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 164 halt_processor(); 165 break; 166 167 case IPI_CPU_TEST: 168 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 169 break; 170 171 default: 172 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 173 this_cpu, which); 174 return IRQ_NONE; 175 } /* Switch */ 176 177 /* before doing more, let in any pending interrupts */ 178 if (ops) { 179 local_irq_enable(); 180 local_irq_disable(); 181 } 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 void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 259 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 260 261 /* Set modes and Enable floating point coprocessor */ 262 init_per_cpu(cpunum); 263 264 disable_sr_hashing(); 265 266 mb(); 267 268 /* Well, support 2.4 linux scheme as well. */ 269 if (cpu_online(cpunum)) { 270 extern void machine_halt(void); /* arch/parisc.../process.c */ 271 272 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 273 machine_halt(); 274 } 275 276 notify_cpu_starting(cpunum); 277 278 set_cpu_online(cpunum, true); 279 280 /* Initialise the idle task for this CPU */ 281 mmgrab(&init_mm); 282 current->active_mm = &init_mm; 283 BUG_ON(current->mm); 284 enter_lazy_tlb(&init_mm, current); 285 286 init_IRQ(); /* make sure no IRQs are enabled or pending */ 287 start_cpu_itimer(); 288 } 289 290 291 /* 292 * Slaves start using C here. Indirectly called from smp_slave_stext. 293 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 294 */ 295 void __init smp_callin(unsigned long pdce_proc) 296 { 297 int slave_id = cpu_now_booting; 298 299 #ifdef CONFIG_64BIT 300 WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32 301 | PAGE0->mem_pdc) != pdce_proc); 302 #endif 303 304 smp_cpu_init(slave_id); 305 306 flush_cache_all_local(); /* start with known state */ 307 flush_tlb_all_local(NULL); 308 309 local_irq_enable(); /* Interrupts have been off until now */ 310 311 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 312 313 /* NOTREACHED */ 314 panic("smp_callin() AAAAaaaaahhhh....\n"); 315 } 316 317 /* 318 * Bring one cpu online. 319 */ 320 int smp_boot_one_cpu(int cpuid, struct task_struct *idle) 321 { 322 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 323 long timeout; 324 325 task_thread_info(idle)->cpu = cpuid; 326 327 /* Let _start know what logical CPU we're booting 328 ** (offset into init_tasks[],cpu_data[]) 329 */ 330 cpu_now_booting = cpuid; 331 332 /* 333 ** boot strap code needs to know the task address since 334 ** it also contains the process stack. 335 */ 336 smp_init_current_idle_task = idle ; 337 mb(); 338 339 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 340 341 /* 342 ** This gets PDC to release the CPU from a very tight loop. 343 ** 344 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 345 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 346 ** is executed after receiving the rendezvous signal (an interrupt to 347 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 348 ** contents of memory are valid." 349 */ 350 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 351 mb(); 352 353 /* 354 * OK, wait a bit for that CPU to finish staggering about. 355 * Slave will set a bit when it reaches smp_cpu_init(). 356 * Once the "monarch CPU" sees the bit change, it can move on. 357 */ 358 for (timeout = 0; timeout < 10000; timeout++) { 359 if(cpu_online(cpuid)) { 360 /* Which implies Slave has started up */ 361 cpu_now_booting = 0; 362 smp_init_current_idle_task = NULL; 363 goto alive ; 364 } 365 udelay(100); 366 barrier(); 367 } 368 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 369 return -1; 370 371 alive: 372 /* Remember the Slave data */ 373 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 374 cpuid, timeout * 100); 375 return 0; 376 } 377 378 void __init smp_prepare_boot_cpu(void) 379 { 380 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 381 382 /* Setup BSP mappings */ 383 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 384 385 set_cpu_online(bootstrap_processor, true); 386 set_cpu_present(bootstrap_processor, true); 387 } 388 389 390 391 /* 392 ** inventory.c:do_inventory() hasn't yet been run and thus we 393 ** don't 'discover' the additional CPUs until later. 394 */ 395 void __init smp_prepare_cpus(unsigned int max_cpus) 396 { 397 int cpu; 398 399 for_each_possible_cpu(cpu) 400 spin_lock_init(&per_cpu(ipi_lock, cpu)); 401 402 init_cpu_present(cpumask_of(0)); 403 404 parisc_max_cpus = max_cpus; 405 if (!max_cpus) 406 printk(KERN_INFO "SMP mode deactivated.\n"); 407 } 408 409 410 void smp_cpus_done(unsigned int cpu_max) 411 { 412 return; 413 } 414 415 416 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 417 { 418 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle)) 419 return -ENOSYS; 420 421 return cpu_online(cpu) ? 0 : -ENOSYS; 422 } 423 424 #ifdef CONFIG_PROC_FS 425 int setup_profiling_timer(unsigned int multiplier) 426 { 427 return -EINVAL; 428 } 429 #endif 430