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