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/pgtable.h> 43 #include <asm/pgalloc.h> 44 #include <asm/processor.h> 45 #include <asm/ptrace.h> 46 #include <asm/unistd.h> 47 #include <asm/cacheflush.h> 48 49 #undef DEBUG_SMP 50 #ifdef DEBUG_SMP 51 static int smp_debug_lvl = 0; 52 #define smp_debug(lvl, printargs...) \ 53 if (lvl >= smp_debug_lvl) \ 54 printk(printargs); 55 #else 56 #define smp_debug(lvl, ...) do { } while(0) 57 #endif /* DEBUG_SMP */ 58 59 volatile struct task_struct *smp_init_current_idle_task; 60 61 /* track which CPU is booting */ 62 static volatile int cpu_now_booting; 63 64 static int parisc_max_cpus = 1; 65 66 static DEFINE_PER_CPU(spinlock_t, ipi_lock); 67 68 enum ipi_message_type { 69 IPI_NOP=0, 70 IPI_RESCHEDULE=1, 71 IPI_CALL_FUNC, 72 IPI_CPU_START, 73 IPI_CPU_STOP, 74 IPI_CPU_TEST 75 }; 76 77 78 /********** SMP inter processor interrupt and communication routines */ 79 80 #undef PER_CPU_IRQ_REGION 81 #ifdef PER_CPU_IRQ_REGION 82 /* XXX REVISIT Ignore for now. 83 ** *May* need this "hook" to register IPI handler 84 ** once we have perCPU ExtIntr switch tables. 85 */ 86 static void 87 ipi_init(int cpuid) 88 { 89 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region 90 91 if(cpu_online(cpuid) ) 92 { 93 switch_to_idle_task(current); 94 } 95 96 return; 97 } 98 #endif 99 100 101 /* 102 ** Yoink this CPU from the runnable list... 103 ** 104 */ 105 static void 106 halt_processor(void) 107 { 108 /* REVISIT : redirect I/O Interrupts to another CPU? */ 109 /* REVISIT : does PM *know* this CPU isn't available? */ 110 set_cpu_online(smp_processor_id(), false); 111 local_irq_disable(); 112 __pdc_cpu_rendezvous(); 113 for (;;) 114 ; 115 } 116 117 118 irqreturn_t __irq_entry 119 ipi_interrupt(int irq, void *dev_id) 120 { 121 int this_cpu = smp_processor_id(); 122 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu); 123 unsigned long ops; 124 unsigned long flags; 125 126 for (;;) { 127 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); 128 spin_lock_irqsave(lock, flags); 129 ops = p->pending_ipi; 130 p->pending_ipi = 0; 131 spin_unlock_irqrestore(lock, flags); 132 133 mb(); /* Order bit clearing and data access. */ 134 135 if (!ops) 136 break; 137 138 while (ops) { 139 unsigned long which = ffz(~ops); 140 141 ops &= ~(1 << which); 142 143 switch (which) { 144 case IPI_NOP: 145 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); 146 break; 147 148 case IPI_RESCHEDULE: 149 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); 150 inc_irq_stat(irq_resched_count); 151 scheduler_ipi(); 152 break; 153 154 case IPI_CALL_FUNC: 155 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); 156 inc_irq_stat(irq_call_count); 157 generic_smp_call_function_interrupt(); 158 break; 159 160 case IPI_CPU_START: 161 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); 162 break; 163 164 case IPI_CPU_STOP: 165 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); 166 halt_processor(); 167 break; 168 169 case IPI_CPU_TEST: 170 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); 171 break; 172 173 default: 174 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", 175 this_cpu, which); 176 return IRQ_NONE; 177 } /* Switch */ 178 /* let in any pending interrupts */ 179 local_irq_enable(); 180 local_irq_disable(); 181 } /* while (ops) */ 182 } 183 return IRQ_HANDLED; 184 } 185 186 187 static inline void 188 ipi_send(int cpu, enum ipi_message_type op) 189 { 190 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu); 191 spinlock_t *lock = &per_cpu(ipi_lock, cpu); 192 unsigned long flags; 193 194 spin_lock_irqsave(lock, flags); 195 p->pending_ipi |= 1 << op; 196 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa); 197 spin_unlock_irqrestore(lock, flags); 198 } 199 200 static void 201 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op) 202 { 203 int cpu; 204 205 for_each_cpu(cpu, mask) 206 ipi_send(cpu, op); 207 } 208 209 static inline void 210 send_IPI_single(int dest_cpu, enum ipi_message_type op) 211 { 212 BUG_ON(dest_cpu == NO_PROC_ID); 213 214 ipi_send(dest_cpu, op); 215 } 216 217 static inline void 218 send_IPI_allbutself(enum ipi_message_type op) 219 { 220 int i; 221 222 for_each_online_cpu(i) { 223 if (i != smp_processor_id()) 224 send_IPI_single(i, op); 225 } 226 } 227 228 229 inline void 230 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } 231 232 void 233 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } 234 235 void 236 smp_send_all_nop(void) 237 { 238 send_IPI_allbutself(IPI_NOP); 239 } 240 241 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 242 { 243 send_IPI_mask(mask, IPI_CALL_FUNC); 244 } 245 246 void arch_send_call_function_single_ipi(int cpu) 247 { 248 send_IPI_single(cpu, IPI_CALL_FUNC); 249 } 250 251 /* 252 * Called by secondaries to update state and initialize CPU registers. 253 */ 254 static void __init 255 smp_cpu_init(int cpunum) 256 { 257 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ 258 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ 259 260 /* Set modes and Enable floating point coprocessor */ 261 init_per_cpu(cpunum); 262 263 disable_sr_hashing(); 264 265 mb(); 266 267 /* Well, support 2.4 linux scheme as well. */ 268 if (cpu_online(cpunum)) { 269 extern void machine_halt(void); /* arch/parisc.../process.c */ 270 271 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); 272 machine_halt(); 273 } 274 275 notify_cpu_starting(cpunum); 276 277 set_cpu_online(cpunum, true); 278 279 /* Initialise the idle task for this CPU */ 280 mmgrab(&init_mm); 281 current->active_mm = &init_mm; 282 BUG_ON(current->mm); 283 enter_lazy_tlb(&init_mm, current); 284 285 init_IRQ(); /* make sure no IRQs are enabled or pending */ 286 start_cpu_itimer(); 287 } 288 289 290 /* 291 * Slaves start using C here. Indirectly called from smp_slave_stext. 292 * Do what start_kernel() and main() do for boot strap processor (aka monarch) 293 */ 294 void __init smp_callin(unsigned long pdce_proc) 295 { 296 int slave_id = cpu_now_booting; 297 298 #ifdef CONFIG_64BIT 299 WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32 300 | PAGE0->mem_pdc) != pdce_proc); 301 #endif 302 303 smp_cpu_init(slave_id); 304 preempt_disable(); 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