1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5 * RajeshwarR: Dec 11, 2007
6 * -- Added support for Inter Processor Interrupts
8 * Vineetg: Nov 1st, 2007
9 * -- Initial Write (Borrowed heavily from ARM)
12 #include <linux/spinlock.h>
13 #include <linux/sched/mm.h>
14 #include <linux/interrupt.h>
15 #include <linux/profile.h>
17 #include <linux/cpu.h>
18 #include <linux/irq.h>
19 #include <linux/atomic.h>
20 #include <linux/cpumask.h>
21 #include <linux/reboot.h>
22 #include <linux/irqdomain.h>
23 #include <linux/export.h>
24 #include <linux/of_fdt.h>
26 #include <asm/mach_desc.h>
27 #include <asm/setup.h>
29 #include <asm/processor.h>
31 #ifndef CONFIG_ARC_HAS_LLSC
32 arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
34 EXPORT_SYMBOL_GPL(smp_atomic_ops_lock);
37 struct plat_smp_ops __weak plat_smp_ops;
39 /* XXX: per cpu ? Only needed once in early secondary boot */
40 struct task_struct *secondary_idle_tsk;
42 /* Called from start_kernel */
43 void __init smp_prepare_boot_cpu(void)
47 static int __init arc_get_cpu_map(const char *name, struct cpumask *cpumask)
49 unsigned long dt_root = of_get_flat_dt_root();
52 buf = of_get_flat_dt_prop(dt_root, name, NULL);
56 if (cpulist_parse(buf, cpumask))
63 * Read from DeviceTree and setup cpu possible mask. If there is no
64 * "possible-cpus" property in DeviceTree pretend all [0..NR_CPUS-1] exist.
66 static void __init arc_init_cpu_possible(void)
68 struct cpumask cpumask;
70 if (arc_get_cpu_map("possible-cpus", &cpumask)) {
71 pr_warn("Failed to get possible-cpus from dtb, pretending all %u cpus exist\n",
74 cpumask_setall(&cpumask);
77 if (!cpumask_test_cpu(0, &cpumask))
78 panic("Master cpu (cpu[0]) is missed in cpu possible mask!");
80 init_cpu_possible(&cpumask);
84 * Called from setup_arch() before calling setup_processor()
86 * - Initialise the CPU possible map early - this describes the CPUs
87 * which may be present or become present in the system.
88 * - Call early smp init hook. This can initialize a specific multi-core
89 * IP which is say common to several platforms (hence not part of
90 * platform specific int_early() hook)
92 void __init smp_init_cpus(void)
94 arc_init_cpu_possible();
96 if (plat_smp_ops.init_early_smp)
97 plat_smp_ops.init_early_smp();
100 /* called from init ( ) => process 1 */
101 void __init smp_prepare_cpus(unsigned int max_cpus)
104 * if platform didn't set the present map already, do it now
105 * boot cpu is set to present already by init/main.c
107 if (num_present_cpus() <= 1)
108 init_cpu_present(cpu_possible_mask);
111 void __init smp_cpus_done(unsigned int max_cpus)
117 * Default smp boot helper for Run-on-reset case where all cores start off
118 * together. Non-masters need to wait for Master to start running.
119 * This is implemented using a flag in memory, which Non-masters spin-wait on.
120 * Master sets it to cpu-id of core to "ungate" it.
122 static volatile int wake_flag;
124 #ifdef CONFIG_ISA_ARCOMPACT
126 #define __boot_read(f) f
127 #define __boot_write(f, v) f = v
131 #define __boot_read(f) arc_read_uncached_32(&f)
132 #define __boot_write(f, v) arc_write_uncached_32(&f, v)
136 static void arc_default_smp_cpu_kick(int cpu, unsigned long pc)
140 __boot_write(wake_flag, cpu);
143 void arc_platform_smp_wait_to_boot(int cpu)
145 /* for halt-on-reset, we've waited already */
146 if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET))
149 while (__boot_read(wake_flag) != cpu)
152 __boot_write(wake_flag, 0);
155 const char *arc_platform_smp_cpuinfo(void)
157 return plat_smp_ops.info ? : "";
161 * The very first "C" code executed by secondary
162 * Called from asm stub in head.S
163 * "current"/R25 already setup by low level boot code
165 void start_kernel_secondary(void)
167 struct mm_struct *mm = &init_mm;
168 unsigned int cpu = smp_processor_id();
170 /* MMU, Caches, Vector Table, Interrupts etc */
175 current->active_mm = mm;
176 cpumask_set_cpu(cpu, mm_cpumask(mm));
178 /* Some SMP H/w setup - for each cpu */
179 if (plat_smp_ops.init_per_cpu)
180 plat_smp_ops.init_per_cpu(cpu);
182 if (machine_desc->init_per_cpu)
183 machine_desc->init_per_cpu(cpu);
185 notify_cpu_starting(cpu);
186 set_cpu_online(cpu, true);
188 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
191 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
195 * Called from kernel_init( ) -> smp_init( ) - for each CPU
197 * At this point, Secondary Processor is "HALT"ed:
198 * -It booted, but was halted in head.S
199 * -It was configured to halt-on-reset
200 * So need to wake it up.
202 * Essential requirements being where to run from (PC) and stack (SP)
204 int __cpu_up(unsigned int cpu, struct task_struct *idle)
206 unsigned long wait_till;
208 secondary_idle_tsk = idle;
210 pr_info("Idle Task [%d] %p", cpu, idle);
211 pr_info("Trying to bring up CPU%u ...\n", cpu);
213 if (plat_smp_ops.cpu_kick)
214 plat_smp_ops.cpu_kick(cpu,
215 (unsigned long)first_lines_of_secondary);
217 arc_default_smp_cpu_kick(cpu, (unsigned long)NULL);
219 /* wait for 1 sec after kicking the secondary */
220 wait_till = jiffies + HZ;
221 while (time_before(jiffies, wait_till)) {
226 if (!cpu_online(cpu)) {
227 pr_info("Timeout: CPU%u FAILED to come up !!!\n", cpu);
231 secondary_idle_tsk = NULL;
236 /*****************************************************************************/
237 /* Inter Processor Interrupt Handling */
238 /*****************************************************************************/
248 * In arches with IRQ for each msg type (above), receiver can use IRQ-id to
249 * figure out what msg was sent. For those which don't (ARC has dedicated IPI
250 * IRQ), the msg-type needs to be conveyed via per-cpu data
253 static DEFINE_PER_CPU(unsigned long, ipi_data);
255 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
257 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
258 unsigned long old, new;
261 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
263 local_irq_save(flags);
266 * Atomically write new msg bit (in case others are writing too),
267 * and read back old value
270 new = old = *ipi_data_ptr;
272 } while (cmpxchg(ipi_data_ptr, old, new) != old);
275 * Call the platform specific IPI kick function, but avoid if possible:
276 * Only do so if there's no pending msg from other concurrent sender(s).
277 * Otherwise, receiver will see this msg as well when it takes the
278 * IPI corresponding to that msg. This is true, even if it is already in
279 * IPI handler, because !@old means it has not yet dequeued the msg(s)
280 * so @new msg can be a free-loader
282 if (plat_smp_ops.ipi_send && !old)
283 plat_smp_ops.ipi_send(cpu);
285 local_irq_restore(flags);
288 static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
292 for_each_cpu(cpu, callmap)
293 ipi_send_msg_one(cpu, msg);
296 void arch_smp_send_reschedule(int cpu)
298 ipi_send_msg_one(cpu, IPI_RESCHEDULE);
301 void smp_send_stop(void)
303 struct cpumask targets;
304 cpumask_copy(&targets, cpu_online_mask);
305 cpumask_clear_cpu(smp_processor_id(), &targets);
306 ipi_send_msg(&targets, IPI_CPU_STOP);
309 void arch_send_call_function_single_ipi(int cpu)
311 ipi_send_msg_one(cpu, IPI_CALL_FUNC);
314 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
316 ipi_send_msg(mask, IPI_CALL_FUNC);
320 * ipi_cpu_stop - handle IPI from smp_send_stop()
322 static void ipi_cpu_stop(void)
327 static inline int __do_IPI(unsigned long msg)
337 generic_smp_call_function_interrupt();
352 * arch-common ISR to handle for inter-processor interrupts
353 * Has hooks for platform specific IPI
355 static irqreturn_t do_IPI(int irq, void *dev_id)
357 unsigned long pending;
358 unsigned long __maybe_unused copy;
360 pr_debug("IPI [%ld] received on cpu %d\n",
361 *this_cpu_ptr(&ipi_data), smp_processor_id());
363 if (plat_smp_ops.ipi_clear)
364 plat_smp_ops.ipi_clear(irq);
367 * "dequeue" the msg corresponding to this IPI (and possibly other
368 * piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
370 copy = pending = xchg(this_cpu_ptr(&ipi_data), 0);
373 unsigned long msg = __ffs(pending);
378 pr_info("IPI with bogus msg %ld in %ld\n", msg, copy);
379 pending &= ~(1U << msg);
386 * API called by platform code to hookup arch-common ISR to their IPI IRQ
388 * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map
389 * function needs to call irq_set_percpu_devid() for IPI IRQ, otherwise
390 * request_percpu_irq() below will fail
392 static DEFINE_PER_CPU(int, ipi_dev);
394 int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq)
396 int *dev = per_cpu_ptr(&ipi_dev, cpu);
397 unsigned int virq = irq_find_mapping(NULL, hwirq);
400 panic("Cannot find virq for root domain and hwirq=%lu", hwirq);
402 /* Boot cpu calls request, all call enable */
406 rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev);
408 panic("Percpu IRQ request failed for %u\n", virq);
411 enable_percpu_irq(virq, 0);