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/pgalloc.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 }; 75 76 77 /********** SMP inter processor interrupt and communication routines */ 78 79 #undef PER_CPU_IRQ_REGION 80 #ifdef PER_CPU_IRQ_REGION 81 /* XXX REVISIT Ignore for now. 82 ** *May* need this "hook" to register IPI handler 83 ** once we have perCPU ExtIntr switch tables. 84 */ 85 static void 86 ipi_init(int cpuid) 87 { 88 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 89 90 if(cpu_online(cpuid) ) 91 { 92 switch_to_idle_task(current); 93 } 94 95 return; 96 } 97 #endif 98 99 100 /* 101 ** Yoink this CPU from the runnable list... 102 ** 103 */ 104 static void 105 halt_processor(void) 106 { 107 /* REVISIT : redirect I/O Interrupts to another CPU? */ 108 /* REVISIT : does PM *know* this CPU isn't available? */ 109 set_cpu_online(smp_processor_id(), false); 110 local_irq_disable(); 111 __pdc_cpu_rendezvous(); 112 for (;;) 113 ; 114 } 115 116 117 irqreturn_t __irq_entry 118 ipi_interrupt(int irq, void *dev_id) 119 { 120 int this_cpu = smp_processor_id(); 121 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu); 122 unsigned long ops; 123 unsigned long flags; 124 125 for (;;) { 126 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 127 spin_lock_irqsave(lock, flags); 128 ops = p->pending_ipi; 129 p->pending_ipi = 0; 130 spin_unlock_irqrestore(lock, flags); 131 132 mb(); /* Order bit clearing and data access. */ 133 134 if (!ops) 135 break; 136 137 while (ops) { 138 unsigned long which = ffz(~ops); 139 140 ops &= ~(1 << which); 141 142 switch (which) { 143 case IPI_NOP: 144 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 145 break; 146 147 case IPI_RESCHEDULE: 148 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 149 inc_irq_stat(irq_resched_count); 150 scheduler_ipi(); 151 break; 152 153 case IPI_CALL_FUNC: 154 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 155 inc_irq_stat(irq_call_count); 156 generic_smp_call_function_interrupt(); 157 break; 158 159 case IPI_CPU_START: 160 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 161 break; 162 163 case IPI_CPU_STOP: 164 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 165 halt_processor(); 166 break; 167 168 case IPI_CPU_TEST: 169 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 170 break; 171 172 default: 173 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 174 this_cpu, which); 175 return IRQ_NONE; 176 } /* Switch */ 177 /* let in any pending interrupts */ 178 local_irq_enable(); 179 local_irq_disable(); 180 } /* while (ops) */ 181 } 182 return IRQ_HANDLED; 183 } 184 185 186 static inline void 187 ipi_send(int cpu, enum ipi_message_type op) 188 { 189 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu); 190 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 191 unsigned long flags; 192 193 spin_lock_irqsave(lock, flags); 194 p->pending_ipi |= 1 << op; 195 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa); 196 spin_unlock_irqrestore(lock, flags); 197 } 198 199 static void 200 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op) 201 { 202 int cpu; 203 204 for_each_cpu(cpu, mask) 205 ipi_send(cpu, op); 206 } 207 208 static inline void 209 send_IPI_single(int dest_cpu, enum ipi_message_type op) 210 { 211 BUG_ON(dest_cpu == NO_PROC_ID); 212 213 ipi_send(dest_cpu, op); 214 } 215 216 static inline void 217 send_IPI_allbutself(enum ipi_message_type op) 218 { 219 int i; 220 221 for_each_online_cpu(i) { 222 if (i != smp_processor_id()) 223 send_IPI_single(i, op); 224 } 225 } 226 227 228 inline void 229 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 230 231 void 232 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 233 234 void 235 smp_send_all_nop(void) 236 { 237 send_IPI_allbutself(IPI_NOP); 238 } 239 240 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 241 { 242 send_IPI_mask(mask, IPI_CALL_FUNC); 243 } 244 245 void arch_send_call_function_single_ipi(int cpu) 246 { 247 send_IPI_single(cpu, IPI_CALL_FUNC); 248 } 249 250 /* 251 * Called by secondaries to update state and initialize CPU registers. 252 */ 253 static void __init 254 smp_cpu_init(int cpunum) 255 { 256 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 257 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 258 259 /* Set modes and Enable floating point coprocessor */ 260 init_per_cpu(cpunum); 261 262 disable_sr_hashing(); 263 264 mb(); 265 266 /* Well, support 2.4 linux scheme as well. */ 267 if (cpu_online(cpunum)) { 268 extern void machine_halt(void); /* arch/parisc.../process.c */ 269 270 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 271 machine_halt(); 272 } 273 274 notify_cpu_starting(cpunum); 275 276 set_cpu_online(cpunum, true); 277 278 /* Initialise the idle task for this CPU */ 279 mmgrab(&init_mm); 280 current->active_mm = &init_mm; 281 BUG_ON(current->mm); 282 enter_lazy_tlb(&init_mm, current); 283 284 init_IRQ(); /* make sure no IRQs are enabled or pending */ 285 start_cpu_itimer(); 286 } 287 288 289 /* 290 * Slaves start using C here. Indirectly called from smp_slave_stext. 291 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 292 */ 293 void __init smp_callin(unsigned long pdce_proc) 294 { 295 int slave_id = cpu_now_booting; 296 297 #ifdef CONFIG_64BIT 298 WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32 299 | PAGE0->mem_pdc) != pdce_proc); 300 #endif 301 302 smp_cpu_init(slave_id); 303 preempt_disable(); 304 305 flush_cache_all_local(); /* start with known state */ 306 flush_tlb_all_local(NULL); 307 308 local_irq_enable(); /* Interrupts have been off until now */ 309 310 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 311 312 /* NOTREACHED */ 313 panic("smp_callin() AAAAaaaaahhhh....\n"); 314 } 315 316 /* 317 * Bring one cpu online. 318 */ 319 int smp_boot_one_cpu(int cpuid, struct task_struct *idle) 320 { 321 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); 322 long timeout; 323 324 task_thread_info(idle)->cpu = cpuid; 325 326 /* Let _start know what logical CPU we're booting 327 ** (offset into init_tasks[],cpu_data[]) 328 */ 329 cpu_now_booting = cpuid; 330 331 /* 332 ** boot strap code needs to know the task address since 333 ** it also contains the process stack. 334 */ 335 smp_init_current_idle_task = idle ; 336 mb(); 337 338 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa); 339 340 /* 341 ** This gets PDC to release the CPU from a very tight loop. 342 ** 343 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: 344 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 345 ** is executed after receiving the rendezvous signal (an interrupt to 346 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 347 ** contents of memory are valid." 348 */ 349 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa); 350 mb(); 351 352 /* 353 * OK, wait a bit for that CPU to finish staggering about. 354 * Slave will set a bit when it reaches smp_cpu_init(). 355 * Once the "monarch CPU" sees the bit change, it can move on. 356 */ 357 for (timeout = 0; timeout < 10000; timeout++) { 358 if(cpu_online(cpuid)) { 359 /* Which implies Slave has started up */ 360 cpu_now_booting = 0; 361 smp_init_current_idle_task = NULL; 362 goto alive ; 363 } 364 udelay(100); 365 barrier(); 366 } 367 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); 368 return -1; 369 370 alive: 371 /* Remember the Slave data */ 372 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", 373 cpuid, timeout * 100); 374 return 0; 375 } 376 377 void __init smp_prepare_boot_cpu(void) 378 { 379 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; 380 381 /* Setup BSP mappings */ 382 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); 383 384 set_cpu_online(bootstrap_processor, true); 385 set_cpu_present(bootstrap_processor, true); 386 } 387 388 389 390 /* 391 ** inventory.c:do_inventory() hasn't yet been run and thus we 392 ** don't 'discover' the additional CPUs until later. 393 */ 394 void __init smp_prepare_cpus(unsigned int max_cpus) 395 { 396 int cpu; 397 398 for_each_possible_cpu(cpu) 399 spin_lock_init(&per_cpu(ipi_lock, cpu)); 400 401 init_cpu_present(cpumask_of(0)); 402 403 parisc_max_cpus = max_cpus; 404 if (!max_cpus) 405 printk(KERN_INFO "SMP mode deactivated.\n"); 406 } 407 408 409 void smp_cpus_done(unsigned int cpu_max) 410 { 411 return; 412 } 413 414 415 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 416 { 417 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle)) 418 return -ENOSYS; 419 420 return cpu_online(cpu) ? 0 : -ENOSYS; 421 } 422 423 #ifdef CONFIG_PROC_FS 424 int setup_profiling_timer(unsigned int multiplier) 425 { 426 return -EINVAL; 427 } 428 #endif 429