1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * RajeshwarR: Dec 11, 2007 9 * -- Added support for Inter Processor Interrupts 10 * 11 * Vineetg: Nov 1st, 2007 12 * -- Initial Write (Borrowed heavily from ARM) 13 */ 14 15 #include <linux/spinlock.h> 16 #include <linux/sched/mm.h> 17 #include <linux/interrupt.h> 18 #include <linux/profile.h> 19 #include <linux/mm.h> 20 #include <linux/cpu.h> 21 #include <linux/irq.h> 22 #include <linux/atomic.h> 23 #include <linux/cpumask.h> 24 #include <linux/reboot.h> 25 #include <linux/irqdomain.h> 26 #include <linux/export.h> 27 28 #include <asm/processor.h> 29 #include <asm/setup.h> 30 #include <asm/mach_desc.h> 31 32 #ifndef CONFIG_ARC_HAS_LLSC 33 arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED; 34 arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED; 35 36 EXPORT_SYMBOL_GPL(smp_atomic_ops_lock); 37 EXPORT_SYMBOL_GPL(smp_bitops_lock); 38 #endif 39 40 struct plat_smp_ops __weak plat_smp_ops; 41 42 /* XXX: per cpu ? Only needed once in early seconday boot */ 43 struct task_struct *secondary_idle_tsk; 44 45 /* Called from start_kernel */ 46 void __init smp_prepare_boot_cpu(void) 47 { 48 } 49 50 /* 51 * Called from setup_arch() before calling setup_processor() 52 * 53 * - Initialise the CPU possible map early - this describes the CPUs 54 * which may be present or become present in the system. 55 * - Call early smp init hook. This can initialize a specific multi-core 56 * IP which is say common to several platforms (hence not part of 57 * platform specific int_early() hook) 58 */ 59 void __init smp_init_cpus(void) 60 { 61 unsigned int i; 62 63 for (i = 0; i < NR_CPUS; i++) 64 set_cpu_possible(i, true); 65 66 if (plat_smp_ops.init_early_smp) 67 plat_smp_ops.init_early_smp(); 68 } 69 70 /* called from init ( ) => process 1 */ 71 void __init smp_prepare_cpus(unsigned int max_cpus) 72 { 73 int i; 74 75 /* 76 * if platform didn't set the present map already, do it now 77 * boot cpu is set to present already by init/main.c 78 */ 79 if (num_present_cpus() <= 1) { 80 for (i = 0; i < max_cpus; i++) 81 set_cpu_present(i, true); 82 } 83 } 84 85 void __init smp_cpus_done(unsigned int max_cpus) 86 { 87 88 } 89 90 /* 91 * Default smp boot helper for Run-on-reset case where all cores start off 92 * together. Non-masters need to wait for Master to start running. 93 * This is implemented using a flag in memory, which Non-masters spin-wait on. 94 * Master sets it to cpu-id of core to "ungate" it. 95 */ 96 static volatile int wake_flag; 97 98 #ifdef CONFIG_ISA_ARCOMPACT 99 100 #define __boot_read(f) f 101 #define __boot_write(f, v) f = v 102 103 #else 104 105 #define __boot_read(f) arc_read_uncached_32(&f) 106 #define __boot_write(f, v) arc_write_uncached_32(&f, v) 107 108 #endif 109 110 static void arc_default_smp_cpu_kick(int cpu, unsigned long pc) 111 { 112 BUG_ON(cpu == 0); 113 114 __boot_write(wake_flag, cpu); 115 } 116 117 void arc_platform_smp_wait_to_boot(int cpu) 118 { 119 /* for halt-on-reset, we've waited already */ 120 if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET)) 121 return; 122 123 while (__boot_read(wake_flag) != cpu) 124 ; 125 126 __boot_write(wake_flag, 0); 127 } 128 129 const char *arc_platform_smp_cpuinfo(void) 130 { 131 return plat_smp_ops.info ? : ""; 132 } 133 134 /* 135 * The very first "C" code executed by secondary 136 * Called from asm stub in head.S 137 * "current"/R25 already setup by low level boot code 138 */ 139 void start_kernel_secondary(void) 140 { 141 struct mm_struct *mm = &init_mm; 142 unsigned int cpu = smp_processor_id(); 143 144 /* MMU, Caches, Vector Table, Interrupts etc */ 145 setup_processor(); 146 147 mmget(mm); 148 mmgrab(mm); 149 current->active_mm = mm; 150 cpumask_set_cpu(cpu, mm_cpumask(mm)); 151 152 /* Some SMP H/w setup - for each cpu */ 153 if (plat_smp_ops.init_per_cpu) 154 plat_smp_ops.init_per_cpu(cpu); 155 156 if (machine_desc->init_per_cpu) 157 machine_desc->init_per_cpu(cpu); 158 159 notify_cpu_starting(cpu); 160 set_cpu_online(cpu, true); 161 162 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu); 163 164 local_irq_enable(); 165 preempt_disable(); 166 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 167 } 168 169 /* 170 * Called from kernel_init( ) -> smp_init( ) - for each CPU 171 * 172 * At this point, Secondary Processor is "HALT"ed: 173 * -It booted, but was halted in head.S 174 * -It was configured to halt-on-reset 175 * So need to wake it up. 176 * 177 * Essential requirements being where to run from (PC) and stack (SP) 178 */ 179 int __cpu_up(unsigned int cpu, struct task_struct *idle) 180 { 181 unsigned long wait_till; 182 183 secondary_idle_tsk = idle; 184 185 pr_info("Idle Task [%d] %p", cpu, idle); 186 pr_info("Trying to bring up CPU%u ...\n", cpu); 187 188 if (plat_smp_ops.cpu_kick) 189 plat_smp_ops.cpu_kick(cpu, 190 (unsigned long)first_lines_of_secondary); 191 else 192 arc_default_smp_cpu_kick(cpu, (unsigned long)NULL); 193 194 /* wait for 1 sec after kicking the secondary */ 195 wait_till = jiffies + HZ; 196 while (time_before(jiffies, wait_till)) { 197 if (cpu_online(cpu)) 198 break; 199 } 200 201 if (!cpu_online(cpu)) { 202 pr_info("Timeout: CPU%u FAILED to comeup !!!\n", cpu); 203 return -1; 204 } 205 206 secondary_idle_tsk = NULL; 207 208 return 0; 209 } 210 211 /* 212 * not supported here 213 */ 214 int setup_profiling_timer(unsigned int multiplier) 215 { 216 return -EINVAL; 217 } 218 219 /*****************************************************************************/ 220 /* Inter Processor Interrupt Handling */ 221 /*****************************************************************************/ 222 223 enum ipi_msg_type { 224 IPI_EMPTY = 0, 225 IPI_RESCHEDULE = 1, 226 IPI_CALL_FUNC, 227 IPI_CPU_STOP, 228 }; 229 230 /* 231 * In arches with IRQ for each msg type (above), receiver can use IRQ-id to 232 * figure out what msg was sent. For those which don't (ARC has dedicated IPI 233 * IRQ), the msg-type needs to be conveyed via per-cpu data 234 */ 235 236 static DEFINE_PER_CPU(unsigned long, ipi_data); 237 238 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg) 239 { 240 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu); 241 unsigned long old, new; 242 unsigned long flags; 243 244 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu); 245 246 local_irq_save(flags); 247 248 /* 249 * Atomically write new msg bit (in case others are writing too), 250 * and read back old value 251 */ 252 do { 253 new = old = READ_ONCE(*ipi_data_ptr); 254 new |= 1U << msg; 255 } while (cmpxchg(ipi_data_ptr, old, new) != old); 256 257 /* 258 * Call the platform specific IPI kick function, but avoid if possible: 259 * Only do so if there's no pending msg from other concurrent sender(s). 260 * Otherwise, recevier will see this msg as well when it takes the 261 * IPI corresponding to that msg. This is true, even if it is already in 262 * IPI handler, because !@old means it has not yet dequeued the msg(s) 263 * so @new msg can be a free-loader 264 */ 265 if (plat_smp_ops.ipi_send && !old) 266 plat_smp_ops.ipi_send(cpu); 267 268 local_irq_restore(flags); 269 } 270 271 static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg) 272 { 273 unsigned int cpu; 274 275 for_each_cpu(cpu, callmap) 276 ipi_send_msg_one(cpu, msg); 277 } 278 279 void smp_send_reschedule(int cpu) 280 { 281 ipi_send_msg_one(cpu, IPI_RESCHEDULE); 282 } 283 284 void smp_send_stop(void) 285 { 286 struct cpumask targets; 287 cpumask_copy(&targets, cpu_online_mask); 288 cpumask_clear_cpu(smp_processor_id(), &targets); 289 ipi_send_msg(&targets, IPI_CPU_STOP); 290 } 291 292 void arch_send_call_function_single_ipi(int cpu) 293 { 294 ipi_send_msg_one(cpu, IPI_CALL_FUNC); 295 } 296 297 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 298 { 299 ipi_send_msg(mask, IPI_CALL_FUNC); 300 } 301 302 /* 303 * ipi_cpu_stop - handle IPI from smp_send_stop() 304 */ 305 static void ipi_cpu_stop(void) 306 { 307 machine_halt(); 308 } 309 310 static inline int __do_IPI(unsigned long msg) 311 { 312 int rc = 0; 313 314 switch (msg) { 315 case IPI_RESCHEDULE: 316 scheduler_ipi(); 317 break; 318 319 case IPI_CALL_FUNC: 320 generic_smp_call_function_interrupt(); 321 break; 322 323 case IPI_CPU_STOP: 324 ipi_cpu_stop(); 325 break; 326 327 default: 328 rc = 1; 329 } 330 331 return rc; 332 } 333 334 /* 335 * arch-common ISR to handle for inter-processor interrupts 336 * Has hooks for platform specific IPI 337 */ 338 irqreturn_t do_IPI(int irq, void *dev_id) 339 { 340 unsigned long pending; 341 unsigned long __maybe_unused copy; 342 343 pr_debug("IPI [%ld] received on cpu %d\n", 344 *this_cpu_ptr(&ipi_data), smp_processor_id()); 345 346 if (plat_smp_ops.ipi_clear) 347 plat_smp_ops.ipi_clear(irq); 348 349 /* 350 * "dequeue" the msg corresponding to this IPI (and possibly other 351 * piggybacked msg from elided IPIs: see ipi_send_msg_one() above) 352 */ 353 copy = pending = xchg(this_cpu_ptr(&ipi_data), 0); 354 355 do { 356 unsigned long msg = __ffs(pending); 357 int rc; 358 359 rc = __do_IPI(msg); 360 if (rc) 361 pr_info("IPI with bogus msg %ld in %ld\n", msg, copy); 362 pending &= ~(1U << msg); 363 } while (pending); 364 365 return IRQ_HANDLED; 366 } 367 368 /* 369 * API called by platform code to hookup arch-common ISR to their IPI IRQ 370 * 371 * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map 372 * function needs to call call irq_set_percpu_devid() for IPI IRQ, otherwise 373 * request_percpu_irq() below will fail 374 */ 375 static DEFINE_PER_CPU(int, ipi_dev); 376 377 int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq) 378 { 379 int *dev = per_cpu_ptr(&ipi_dev, cpu); 380 unsigned int virq = irq_find_mapping(NULL, hwirq); 381 382 if (!virq) 383 panic("Cannot find virq for root domain and hwirq=%lu", hwirq); 384 385 /* Boot cpu calls request, all call enable */ 386 if (!cpu) { 387 int rc; 388 389 rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev); 390 if (rc) 391 panic("Percpu IRQ request failed for %u\n", virq); 392 } 393 394 enable_percpu_irq(virq, 0); 395 396 return 0; 397 } 398