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
);
192 local_async_enable();
195 * OK, it's off to the idle thread for us
197 cpu_startup_entry(CPUHP_ONLINE
);
200 #ifdef CONFIG_HOTPLUG_CPU
201 static int op_cpu_disable(unsigned int cpu
)
204 * If we don't have a cpu_die method, abort before we reach the point
205 * of no return. CPU0 may not have an cpu_ops, so test for it.
207 if (!cpu_ops
[cpu
] || !cpu_ops
[cpu
]->cpu_die
)
211 * We may need to abort a hot unplug for some other mechanism-specific
214 if (cpu_ops
[cpu
]->cpu_disable
)
215 return cpu_ops
[cpu
]->cpu_disable(cpu
);
221 * __cpu_disable runs on the processor to be shutdown.
223 int __cpu_disable(void)
225 unsigned int cpu
= smp_processor_id();
228 ret
= op_cpu_disable(cpu
);
233 * Take this CPU offline. Once we clear this, we can't return,
234 * and we must not schedule until we're ready to give up the cpu.
236 set_cpu_online(cpu
, false);
239 * OK - migrate IRQs away from this CPU
241 irq_migrate_all_off_this_cpu();
246 static int op_cpu_kill(unsigned int cpu
)
249 * If we have no means of synchronising with the dying CPU, then assume
250 * that it is really dead. We can only wait for an arbitrary length of
251 * time and hope that it's dead, so let's skip the wait and just hope.
253 if (!cpu_ops
[cpu
]->cpu_kill
)
256 return cpu_ops
[cpu
]->cpu_kill(cpu
);
260 * called on the thread which is asking for a CPU to be shutdown -
261 * waits until shutdown has completed, or it is timed out.
263 void __cpu_die(unsigned int cpu
)
267 if (!cpu_wait_death(cpu
, 5)) {
268 pr_crit("CPU%u: cpu didn't die\n", cpu
);
271 pr_notice("CPU%u: shutdown\n", cpu
);
274 * Now that the dying CPU is beyond the point of no return w.r.t.
275 * in-kernel synchronisation, try to get the firwmare to help us to
276 * verify that it has really left the kernel before we consider
277 * clobbering anything it might still be using.
279 err
= op_cpu_kill(cpu
);
281 pr_warn("CPU%d may not have shut down cleanly: %d\n",
286 * Called from the idle thread for the CPU which has been shutdown.
288 * Note that we disable IRQs here, but do not re-enable them
289 * before returning to the caller. This is also the behaviour
290 * of the other hotplug-cpu capable cores, so presumably coming
291 * out of idle fixes this.
295 unsigned int cpu
= smp_processor_id();
301 /* Tell __cpu_die() that this CPU is now safe to dispose of */
302 (void)cpu_report_death();
305 * Actually shutdown the CPU. This must never fail. The specific hotplug
306 * mechanism must perform all required cache maintenance to ensure that
307 * no dirty lines are lost in the process of shutting down the CPU.
309 cpu_ops
[cpu
]->cpu_die(cpu
);
315 static void __init
hyp_mode_check(void)
317 if (is_hyp_mode_available())
318 pr_info("CPU: All CPU(s) started at EL2\n");
319 else if (is_hyp_mode_mismatched())
320 WARN_TAINT(1, TAINT_CPU_OUT_OF_SPEC
,
321 "CPU: CPUs started in inconsistent modes");
323 pr_info("CPU: All CPU(s) started at EL1\n");
326 void __init
smp_cpus_done(unsigned int max_cpus
)
328 pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
329 setup_cpu_features();
331 apply_alternatives_all();
334 void __init
smp_prepare_boot_cpu(void)
336 cpuinfo_store_boot_cpu();
337 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
340 static u64 __init
of_get_cpu_mpidr(struct device_node
*dn
)
346 * A cpu node with missing "reg" property is
347 * considered invalid to build a cpu_logical_map
350 cell
= of_get_property(dn
, "reg", NULL
);
352 pr_err("%s: missing reg property\n", dn
->full_name
);
356 hwid
= of_read_number(cell
, of_n_addr_cells(dn
));
358 * Non affinity bits must be set to 0 in the DT
360 if (hwid
& ~MPIDR_HWID_BITMASK
) {
361 pr_err("%s: invalid reg property\n", dn
->full_name
);
368 * Duplicate MPIDRs are a recipe for disaster. Scan all initialized
369 * entries and check for duplicates. If any is found just ignore the
370 * cpu. cpu_logical_map was initialized to INVALID_HWID to avoid
371 * matching valid MPIDR values.
373 static bool __init
is_mpidr_duplicate(unsigned int cpu
, u64 hwid
)
377 for (i
= 1; (i
< cpu
) && (i
< NR_CPUS
); i
++)
378 if (cpu_logical_map(i
) == hwid
)
384 * Initialize cpu operations for a logical cpu and
385 * set it in the possible mask on success
387 static int __init
smp_cpu_setup(int cpu
)
389 if (cpu_read_ops(cpu
))
392 if (cpu_ops
[cpu
]->cpu_init(cpu
))
395 set_cpu_possible(cpu
, true);
400 static bool bootcpu_valid __initdata
;
401 static unsigned int cpu_count
= 1;
405 * acpi_map_gic_cpu_interface - parse processor MADT entry
407 * Carry out sanity checks on MADT processor entry and initialize
408 * cpu_logical_map on success
411 acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt
*processor
)
413 u64 hwid
= processor
->arm_mpidr
;
415 if (!(processor
->flags
& ACPI_MADT_ENABLED
)) {
416 pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid
);
420 if (hwid
& ~MPIDR_HWID_BITMASK
|| hwid
== INVALID_HWID
) {
421 pr_err("skipping CPU entry with invalid MPIDR 0x%llx\n", hwid
);
425 if (is_mpidr_duplicate(cpu_count
, hwid
)) {
426 pr_err("duplicate CPU MPIDR 0x%llx in MADT\n", hwid
);
430 /* Check if GICC structure of boot CPU is available in the MADT */
431 if (cpu_logical_map(0) == hwid
) {
433 pr_err("duplicate boot CPU MPIDR: 0x%llx in MADT\n",
437 bootcpu_valid
= true;
441 if (cpu_count
>= NR_CPUS
)
444 /* map the logical cpu id to cpu MPIDR */
445 cpu_logical_map(cpu_count
) = hwid
;
448 * Set-up the ACPI parking protocol cpu entries
449 * while initializing the cpu_logical_map to
450 * avoid parsing MADT entries multiple times for
451 * nothing (ie a valid cpu_logical_map entry should
452 * contain a valid parking protocol data set to
453 * initialize the cpu if the parking protocol is
454 * the only available enable method).
456 acpi_set_mailbox_entry(cpu_count
, processor
);
462 acpi_parse_gic_cpu_interface(struct acpi_subtable_header
*header
,
463 const unsigned long end
)
465 struct acpi_madt_generic_interrupt
*processor
;
467 processor
= (struct acpi_madt_generic_interrupt
*)header
;
468 if (BAD_MADT_GICC_ENTRY(processor
, end
))
471 acpi_table_print_madt_entry(header
);
473 acpi_map_gic_cpu_interface(processor
);
478 #define acpi_table_parse_madt(...) do { } while (0)
482 * Enumerate the possible CPU set from the device tree and build the
483 * cpu logical map array containing MPIDR values related to logical
484 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
486 static void __init
of_parse_and_init_cpus(void)
488 struct device_node
*dn
= NULL
;
490 while ((dn
= of_find_node_by_type(dn
, "cpu"))) {
491 u64 hwid
= of_get_cpu_mpidr(dn
);
493 if (hwid
== INVALID_HWID
)
496 if (is_mpidr_duplicate(cpu_count
, hwid
)) {
497 pr_err("%s: duplicate cpu reg properties in the DT\n",
503 * The numbering scheme requires that the boot CPU
504 * must be assigned logical id 0. Record it so that
505 * the logical map built from DT is validated and can
508 if (hwid
== cpu_logical_map(0)) {
510 pr_err("%s: duplicate boot cpu reg property in DT\n",
515 bootcpu_valid
= true;
518 * cpu_logical_map has already been
519 * initialized and the boot cpu doesn't need
520 * the enable-method so continue without
526 if (cpu_count
>= NR_CPUS
)
529 pr_debug("cpu logical map 0x%llx\n", hwid
);
530 cpu_logical_map(cpu_count
) = hwid
;
537 * Enumerate the possible CPU set from the device tree or ACPI and build the
538 * cpu logical map array containing MPIDR values related to logical
539 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
541 void __init
smp_init_cpus(void)
546 of_parse_and_init_cpus();
549 * do a walk of MADT to determine how many CPUs
550 * we have including disabled CPUs, and get information
551 * we need for SMP init
553 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT
,
554 acpi_parse_gic_cpu_interface
, 0);
556 if (cpu_count
> NR_CPUS
)
557 pr_warn("no. of cores (%d) greater than configured maximum of %d - clipping\n",
560 if (!bootcpu_valid
) {
561 pr_err("missing boot CPU MPIDR, not enabling secondaries\n");
566 * We need to set the cpu_logical_map entries before enabling
567 * the cpus so that cpu processor description entries (DT cpu nodes
568 * and ACPI MADT entries) can be retrieved by matching the cpu hwid
569 * with entries in cpu_logical_map while initializing the cpus.
570 * If the cpu set-up fails, invalidate the cpu_logical_map entry.
572 for (i
= 1; i
< NR_CPUS
; i
++) {
573 if (cpu_logical_map(i
) != INVALID_HWID
) {
574 if (smp_cpu_setup(i
))
575 cpu_logical_map(i
) = INVALID_HWID
;
580 void __init
smp_prepare_cpus(unsigned int max_cpus
)
583 unsigned int cpu
, ncores
= num_possible_cpus();
587 smp_store_cpu_info(smp_processor_id());
590 * are we trying to boot more cores than exist?
592 if (max_cpus
> ncores
)
595 /* Don't bother if we're effectively UP */
600 * Initialise the present map (which describes the set of CPUs
601 * actually populated at the present time) and release the
602 * secondaries from the bootloader.
604 * Make sure we online at most (max_cpus - 1) additional CPUs.
607 for_each_possible_cpu(cpu
) {
611 if (cpu
== smp_processor_id())
617 err
= cpu_ops
[cpu
]->cpu_prepare(cpu
);
621 set_cpu_present(cpu
, true);
626 void (*__smp_cross_call
)(const struct cpumask
*, unsigned int);
628 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
630 __smp_cross_call
= fn
;
633 static const char *ipi_types
[NR_IPI
] __tracepoint_string
= {
634 #define S(x,s) [x] = s
635 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
636 S(IPI_CALL_FUNC
, "Function call interrupts"),
637 S(IPI_CPU_STOP
, "CPU stop interrupts"),
638 S(IPI_TIMER
, "Timer broadcast interrupts"),
639 S(IPI_IRQ_WORK
, "IRQ work interrupts"),
640 S(IPI_WAKEUP
, "CPU wake-up interrupts"),
643 static void smp_cross_call(const struct cpumask
*target
, unsigned int ipinr
)
645 trace_ipi_raise(target
, ipi_types
[ipinr
]);
646 __smp_cross_call(target
, ipinr
);
649 void show_ipi_list(struct seq_file
*p
, int prec
)
653 for (i
= 0; i
< NR_IPI
; i
++) {
654 seq_printf(p
, "%*s%u:%s", prec
- 1, "IPI", i
,
655 prec
>= 4 ? " " : "");
656 for_each_online_cpu(cpu
)
657 seq_printf(p
, "%10u ",
658 __get_irq_stat(cpu
, ipi_irqs
[i
]));
659 seq_printf(p
, " %s\n", ipi_types
[i
]);
663 u64
smp_irq_stat_cpu(unsigned int cpu
)
668 for (i
= 0; i
< NR_IPI
; i
++)
669 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
674 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
676 smp_cross_call(mask
, IPI_CALL_FUNC
);
679 void arch_send_call_function_single_ipi(int cpu
)
681 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC
);
684 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
685 void arch_send_wakeup_ipi_mask(const struct cpumask
*mask
)
687 smp_cross_call(mask
, IPI_WAKEUP
);
691 #ifdef CONFIG_IRQ_WORK
692 void arch_irq_work_raise(void)
694 if (__smp_cross_call
)
695 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK
);
699 static DEFINE_RAW_SPINLOCK(stop_lock
);
702 * ipi_cpu_stop - handle IPI from smp_send_stop()
704 static void ipi_cpu_stop(unsigned int cpu
)
706 if (system_state
== SYSTEM_BOOTING
||
707 system_state
== SYSTEM_RUNNING
) {
708 raw_spin_lock(&stop_lock
);
709 pr_crit("CPU%u: stopping\n", cpu
);
711 raw_spin_unlock(&stop_lock
);
714 set_cpu_online(cpu
, false);
723 * Main handler for inter-processor interrupts
725 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
727 unsigned int cpu
= smp_processor_id();
728 struct pt_regs
*old_regs
= set_irq_regs(regs
);
730 if ((unsigned)ipinr
< NR_IPI
) {
731 trace_ipi_entry_rcuidle(ipi_types
[ipinr
]);
732 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
742 generic_smp_call_function_interrupt();
752 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
755 tick_receive_broadcast();
760 #ifdef CONFIG_IRQ_WORK
768 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
770 WARN_ONCE(!acpi_parking_protocol_valid(cpu
),
771 "CPU%u: Wake-up IPI outside the ACPI parking protocol\n",
777 pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu
, ipinr
);
781 if ((unsigned)ipinr
< NR_IPI
)
782 trace_ipi_exit_rcuidle(ipi_types
[ipinr
]);
783 set_irq_regs(old_regs
);
786 void smp_send_reschedule(int cpu
)
788 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
791 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
792 void tick_broadcast(const struct cpumask
*mask
)
794 smp_cross_call(mask
, IPI_TIMER
);
798 void smp_send_stop(void)
800 unsigned long timeout
;
802 if (num_online_cpus() > 1) {
805 cpumask_copy(&mask
, cpu_online_mask
);
806 cpumask_clear_cpu(smp_processor_id(), &mask
);
808 smp_cross_call(&mask
, IPI_CPU_STOP
);
811 /* Wait up to one second for other CPUs to stop */
812 timeout
= USEC_PER_SEC
;
813 while (num_online_cpus() > 1 && timeout
--)
816 if (num_online_cpus() > 1)
817 pr_warning("SMP: failed to stop secondary CPUs\n");
823 int setup_profiling_timer(unsigned int multiplier
)