2 * SMP initialisation and IPI support
3 * Based on arch/arm/kernel/smp.c
5 * Copyright (C) 2012 ARM Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #include <linux/acpi.h>
21 #include <linux/delay.h>
22 #include <linux/init.h>
23 #include <linux/spinlock.h>
24 #include <linux/sched.h>
25 #include <linux/interrupt.h>
26 #include <linux/cache.h>
27 #include <linux/profile.h>
28 #include <linux/errno.h>
30 #include <linux/err.h>
31 #include <linux/cpu.h>
32 #include <linux/smp.h>
33 #include <linux/seq_file.h>
34 #include <linux/irq.h>
35 #include <linux/percpu.h>
36 #include <linux/clockchips.h>
37 #include <linux/completion.h>
39 #include <linux/irq_work.h>
41 #include <asm/alternative.h>
42 #include <asm/atomic.h>
43 #include <asm/cacheflush.h>
45 #include <asm/cputype.h>
46 #include <asm/cpu_ops.h>
47 #include <asm/mmu_context.h>
48 #include <asm/pgtable.h>
49 #include <asm/pgalloc.h>
50 #include <asm/processor.h>
51 #include <asm/smp_plat.h>
52 #include <asm/sections.h>
53 #include <asm/tlbflush.h>
54 #include <asm/ptrace.h>
57 #define CREATE_TRACE_POINTS
58 #include <trace/events/ipi.h>
61 * as from 2.5, kernels no longer have an init_tasks structure
62 * so we need some other way of telling a new secondary core
63 * where to place its SVC stack
65 struct secondary_data secondary_data;
77 * Boot a secondary CPU, and assign it the specified idle task.
78 * This also gives us the initial stack to use for this CPU.
80 static int boot_secondary(unsigned int cpu, struct task_struct *idle)
82 if (cpu_ops[cpu]->cpu_boot)
83 return cpu_ops[cpu]->cpu_boot(cpu);
88 static DECLARE_COMPLETION(cpu_running);
90 int __cpu_up(unsigned int cpu, struct task_struct *idle)
95 * We need to tell the secondary core where to find its stack and the
98 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
99 __flush_dcache_area(&secondary_data, sizeof(secondary_data));
102 * Now bring the CPU into our world.
104 ret = boot_secondary(cpu, idle);
107 * CPU was successfully started, wait for it to come online or
110 wait_for_completion_timeout(&cpu_running,
111 msecs_to_jiffies(1000));
113 if (!cpu_online(cpu)) {
114 pr_crit("CPU%u: failed to come online\n", cpu);
118 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
121 secondary_data.stack = NULL;
126 static void smp_store_cpu_info(unsigned int cpuid)
128 store_cpu_topology(cpuid);
132 * This is the secondary CPU boot entry. We're using this CPUs
133 * idle thread stack, but a set of temporary page tables.
135 asmlinkage void secondary_start_kernel(void)
137 struct mm_struct *mm = &init_mm;
138 unsigned int cpu = smp_processor_id();
141 * All kernel threads share the same mm context; grab a
142 * reference and switch to it.
144 atomic_inc(&mm->mm_count);
145 current->active_mm = mm;
147 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
150 * TTBR0 is only used for the identity mapping at this stage. Make it
151 * point to zero page to avoid speculatively fetching new entries.
153 cpu_uninstall_idmap();
156 trace_hardirqs_off();
159 * If the system has established the capabilities, make sure
160 * this CPU ticks all of those. If it doesn't, the CPU will
161 * fail to come online.
163 verify_local_cpu_capabilities();
165 if (cpu_ops[cpu]->cpu_postboot)
166 cpu_ops[cpu]->cpu_postboot();
169 * Log the CPU info before it is marked online and might get read.
174 * Enable GIC and timers.
176 notify_cpu_starting(cpu);
178 smp_store_cpu_info(cpu);
181 * OK, now it's safe to let the boot CPU continue. Wait for
182 * the CPU migration code to notice that the CPU is online
183 * before we continue.
185 pr_info("CPU%u: Booted secondary processor [%08x]\n",
186 cpu, read_cpuid_id());
187 set_cpu_online(cpu, true);
188 complete(&cpu_running);
191 local_async_enable();
194 * OK, it's off to the idle thread for us
196 cpu_startup_entry(CPUHP_ONLINE);
199 #ifdef CONFIG_HOTPLUG_CPU
200 static int op_cpu_disable(unsigned int cpu)
203 * If we don't have a cpu_die method, abort before we reach the point
204 * of no return. CPU0 may not have an cpu_ops, so test for it.
206 if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_die)
210 * We may need to abort a hot unplug for some other mechanism-specific
213 if (cpu_ops[cpu]->cpu_disable)
214 return cpu_ops[cpu]->cpu_disable(cpu);
220 * __cpu_disable runs on the processor to be shutdown.
222 int __cpu_disable(void)
224 unsigned int cpu = smp_processor_id();
227 ret = op_cpu_disable(cpu);
232 * Take this CPU offline. Once we clear this, we can't return,
233 * and we must not schedule until we're ready to give up the cpu.
235 set_cpu_online(cpu, false);
238 * OK - migrate IRQs away from this CPU
240 irq_migrate_all_off_this_cpu();
245 static int op_cpu_kill(unsigned int cpu)
248 * If we have no means of synchronising with the dying CPU, then assume
249 * that it is really dead. We can only wait for an arbitrary length of
250 * time and hope that it's dead, so let's skip the wait and just hope.
252 if (!cpu_ops[cpu]->cpu_kill)
255 return cpu_ops[cpu]->cpu_kill(cpu);
259 * called on the thread which is asking for a CPU to be shutdown -
260 * waits until shutdown has completed, or it is timed out.
262 void __cpu_die(unsigned int cpu)
266 if (!cpu_wait_death(cpu, 5)) {
267 pr_crit("CPU%u: cpu didn't die\n", cpu);
270 pr_notice("CPU%u: shutdown\n", cpu);
273 * Now that the dying CPU is beyond the point of no return w.r.t.
274 * in-kernel synchronisation, try to get the firwmare to help us to
275 * verify that it has really left the kernel before we consider
276 * clobbering anything it might still be using.
278 err = op_cpu_kill(cpu);
280 pr_warn("CPU%d may not have shut down cleanly: %d\n",
285 * Called from the idle thread for the CPU which has been shutdown.
287 * Note that we disable IRQs here, but do not re-enable them
288 * before returning to the caller. This is also the behaviour
289 * of the other hotplug-cpu capable cores, so presumably coming
290 * out of idle fixes this.
294 unsigned int cpu = smp_processor_id();
300 /* Tell __cpu_die() that this CPU is now safe to dispose of */
301 (void)cpu_report_death();
304 * Actually shutdown the CPU. This must never fail. The specific hotplug
305 * mechanism must perform all required cache maintenance to ensure that
306 * no dirty lines are lost in the process of shutting down the CPU.
308 cpu_ops[cpu]->cpu_die(cpu);
315 * Kill the calling secondary CPU, early in bringup before it is turned
318 void cpu_die_early(void)
320 int cpu = smp_processor_id();
322 pr_crit("CPU%d: will not boot\n", cpu);
324 /* Mark this CPU absent */
325 set_cpu_present(cpu, 0);
327 #ifdef CONFIG_HOTPLUG_CPU
328 /* Check if we can park ourselves */
329 if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_die)
330 cpu_ops[cpu]->cpu_die(cpu);
336 static void __init hyp_mode_check(void)
338 if (is_hyp_mode_available())
339 pr_info("CPU: All CPU(s) started at EL2\n");
340 else if (is_hyp_mode_mismatched())
341 WARN_TAINT(1, TAINT_CPU_OUT_OF_SPEC,
342 "CPU: CPUs started in inconsistent modes");
344 pr_info("CPU: All CPU(s) started at EL1\n");
347 void __init smp_cpus_done(unsigned int max_cpus)
349 pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
350 setup_cpu_features();
352 apply_alternatives_all();
355 void __init smp_prepare_boot_cpu(void)
357 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
358 cpuinfo_store_boot_cpu();
361 static u64 __init of_get_cpu_mpidr(struct device_node *dn)
367 * A cpu node with missing "reg" property is
368 * considered invalid to build a cpu_logical_map
371 cell = of_get_property(dn, "reg", NULL);
373 pr_err("%s: missing reg property\n", dn->full_name);
377 hwid = of_read_number(cell, of_n_addr_cells(dn));
379 * Non affinity bits must be set to 0 in the DT
381 if (hwid & ~MPIDR_HWID_BITMASK) {
382 pr_err("%s: invalid reg property\n", dn->full_name);
389 * Duplicate MPIDRs are a recipe for disaster. Scan all initialized
390 * entries and check for duplicates. If any is found just ignore the
391 * cpu. cpu_logical_map was initialized to INVALID_HWID to avoid
392 * matching valid MPIDR values.
394 static bool __init is_mpidr_duplicate(unsigned int cpu, u64 hwid)
398 for (i = 1; (i < cpu) && (i < NR_CPUS); i++)
399 if (cpu_logical_map(i) == hwid)
405 * Initialize cpu operations for a logical cpu and
406 * set it in the possible mask on success
408 static int __init smp_cpu_setup(int cpu)
410 if (cpu_read_ops(cpu))
413 if (cpu_ops[cpu]->cpu_init(cpu))
416 set_cpu_possible(cpu, true);
421 static bool bootcpu_valid __initdata;
422 static unsigned int cpu_count = 1;
426 * acpi_map_gic_cpu_interface - parse processor MADT entry
428 * Carry out sanity checks on MADT processor entry and initialize
429 * cpu_logical_map on success
432 acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
434 u64 hwid = processor->arm_mpidr;
436 if (!(processor->flags & ACPI_MADT_ENABLED)) {
437 pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
441 if (hwid & ~MPIDR_HWID_BITMASK || hwid == INVALID_HWID) {
442 pr_err("skipping CPU entry with invalid MPIDR 0x%llx\n", hwid);
446 if (is_mpidr_duplicate(cpu_count, hwid)) {
447 pr_err("duplicate CPU MPIDR 0x%llx in MADT\n", hwid);
451 /* Check if GICC structure of boot CPU is available in the MADT */
452 if (cpu_logical_map(0) == hwid) {
454 pr_err("duplicate boot CPU MPIDR: 0x%llx in MADT\n",
458 bootcpu_valid = true;
462 if (cpu_count >= NR_CPUS)
465 /* map the logical cpu id to cpu MPIDR */
466 cpu_logical_map(cpu_count) = hwid;
469 * Set-up the ACPI parking protocol cpu entries
470 * while initializing the cpu_logical_map to
471 * avoid parsing MADT entries multiple times for
472 * nothing (ie a valid cpu_logical_map entry should
473 * contain a valid parking protocol data set to
474 * initialize the cpu if the parking protocol is
475 * the only available enable method).
477 acpi_set_mailbox_entry(cpu_count, processor);
483 acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header,
484 const unsigned long end)
486 struct acpi_madt_generic_interrupt *processor;
488 processor = (struct acpi_madt_generic_interrupt *)header;
489 if (BAD_MADT_GICC_ENTRY(processor, end))
492 acpi_table_print_madt_entry(header);
494 acpi_map_gic_cpu_interface(processor);
499 #define acpi_table_parse_madt(...) do { } while (0)
503 * Enumerate the possible CPU set from the device tree and build the
504 * cpu logical map array containing MPIDR values related to logical
505 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
507 static void __init of_parse_and_init_cpus(void)
509 struct device_node *dn = NULL;
511 while ((dn = of_find_node_by_type(dn, "cpu"))) {
512 u64 hwid = of_get_cpu_mpidr(dn);
514 if (hwid == INVALID_HWID)
517 if (is_mpidr_duplicate(cpu_count, hwid)) {
518 pr_err("%s: duplicate cpu reg properties in the DT\n",
524 * The numbering scheme requires that the boot CPU
525 * must be assigned logical id 0. Record it so that
526 * the logical map built from DT is validated and can
529 if (hwid == cpu_logical_map(0)) {
531 pr_err("%s: duplicate boot cpu reg property in DT\n",
536 bootcpu_valid = true;
539 * cpu_logical_map has already been
540 * initialized and the boot cpu doesn't need
541 * the enable-method so continue without
547 if (cpu_count >= NR_CPUS)
550 pr_debug("cpu logical map 0x%llx\n", hwid);
551 cpu_logical_map(cpu_count) = hwid;
558 * Enumerate the possible CPU set from the device tree or ACPI and build the
559 * cpu logical map array containing MPIDR values related to logical
560 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
562 void __init smp_init_cpus(void)
567 of_parse_and_init_cpus();
570 * do a walk of MADT to determine how many CPUs
571 * we have including disabled CPUs, and get information
572 * we need for SMP init
574 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
575 acpi_parse_gic_cpu_interface, 0);
577 if (cpu_count > NR_CPUS)
578 pr_warn("no. of cores (%d) greater than configured maximum of %d - clipping\n",
581 if (!bootcpu_valid) {
582 pr_err("missing boot CPU MPIDR, not enabling secondaries\n");
587 * We need to set the cpu_logical_map entries before enabling
588 * the cpus so that cpu processor description entries (DT cpu nodes
589 * and ACPI MADT entries) can be retrieved by matching the cpu hwid
590 * with entries in cpu_logical_map while initializing the cpus.
591 * If the cpu set-up fails, invalidate the cpu_logical_map entry.
593 for (i = 1; i < NR_CPUS; i++) {
594 if (cpu_logical_map(i) != INVALID_HWID) {
595 if (smp_cpu_setup(i))
596 cpu_logical_map(i) = INVALID_HWID;
601 void __init smp_prepare_cpus(unsigned int max_cpus)
604 unsigned int cpu, ncores = num_possible_cpus();
608 smp_store_cpu_info(smp_processor_id());
611 * are we trying to boot more cores than exist?
613 if (max_cpus > ncores)
616 /* Don't bother if we're effectively UP */
621 * Initialise the present map (which describes the set of CPUs
622 * actually populated at the present time) and release the
623 * secondaries from the bootloader.
625 * Make sure we online at most (max_cpus - 1) additional CPUs.
628 for_each_possible_cpu(cpu) {
632 if (cpu == smp_processor_id())
638 err = cpu_ops[cpu]->cpu_prepare(cpu);
642 set_cpu_present(cpu, true);
647 void (*__smp_cross_call)(const struct cpumask *, unsigned int);
649 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
651 __smp_cross_call = fn;
654 static const char *ipi_types[NR_IPI] __tracepoint_string = {
655 #define S(x,s) [x] = s
656 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
657 S(IPI_CALL_FUNC, "Function call interrupts"),
658 S(IPI_CPU_STOP, "CPU stop interrupts"),
659 S(IPI_TIMER, "Timer broadcast interrupts"),
660 S(IPI_IRQ_WORK, "IRQ work interrupts"),
661 S(IPI_WAKEUP, "CPU wake-up interrupts"),
664 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
666 trace_ipi_raise(target, ipi_types[ipinr]);
667 __smp_cross_call(target, ipinr);
670 void show_ipi_list(struct seq_file *p, int prec)
674 for (i = 0; i < NR_IPI; i++) {
675 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
676 prec >= 4 ? " " : "");
677 for_each_online_cpu(cpu)
678 seq_printf(p, "%10u ",
679 __get_irq_stat(cpu, ipi_irqs[i]));
680 seq_printf(p, " %s\n", ipi_types[i]);
684 u64 smp_irq_stat_cpu(unsigned int cpu)
689 for (i = 0; i < NR_IPI; i++)
690 sum += __get_irq_stat(cpu, ipi_irqs[i]);
695 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
697 smp_cross_call(mask, IPI_CALL_FUNC);
700 void arch_send_call_function_single_ipi(int cpu)
702 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
705 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
706 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
708 smp_cross_call(mask, IPI_WAKEUP);
712 #ifdef CONFIG_IRQ_WORK
713 void arch_irq_work_raise(void)
715 if (__smp_cross_call)
716 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
720 static DEFINE_RAW_SPINLOCK(stop_lock);
723 * ipi_cpu_stop - handle IPI from smp_send_stop()
725 static void ipi_cpu_stop(unsigned int cpu)
727 if (system_state == SYSTEM_BOOTING ||
728 system_state == SYSTEM_RUNNING) {
729 raw_spin_lock(&stop_lock);
730 pr_crit("CPU%u: stopping\n", cpu);
732 raw_spin_unlock(&stop_lock);
735 set_cpu_online(cpu, false);
744 * Main handler for inter-processor interrupts
746 void handle_IPI(int ipinr, struct pt_regs *regs)
748 unsigned int cpu = smp_processor_id();
749 struct pt_regs *old_regs = set_irq_regs(regs);
751 if ((unsigned)ipinr < NR_IPI) {
752 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
753 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
763 generic_smp_call_function_interrupt();
773 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
776 tick_receive_broadcast();
781 #ifdef CONFIG_IRQ_WORK
789 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
791 WARN_ONCE(!acpi_parking_protocol_valid(cpu),
792 "CPU%u: Wake-up IPI outside the ACPI parking protocol\n",
798 pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr);
802 if ((unsigned)ipinr < NR_IPI)
803 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
804 set_irq_regs(old_regs);
807 void smp_send_reschedule(int cpu)
809 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
812 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
813 void tick_broadcast(const struct cpumask *mask)
815 smp_cross_call(mask, IPI_TIMER);
819 void smp_send_stop(void)
821 unsigned long timeout;
823 if (num_online_cpus() > 1) {
826 cpumask_copy(&mask, cpu_online_mask);
827 cpumask_clear_cpu(smp_processor_id(), &mask);
829 smp_cross_call(&mask, IPI_CPU_STOP);
832 /* Wait up to one second for other CPUs to stop */
833 timeout = USEC_PER_SEC;
834 while (num_online_cpus() > 1 && timeout--)
837 if (num_online_cpus() > 1)
838 pr_warning("SMP: failed to stop secondary CPUs\n");
844 int setup_profiling_timer(unsigned int multiplier)