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>
49 #include <asm/pgtable.h>
50 #include <asm/pgalloc.h>
51 #include <asm/processor.h>
52 #include <asm/smp_plat.h>
53 #include <asm/sections.h>
54 #include <asm/tlbflush.h>
55 #include <asm/ptrace.h>
58 #define CREATE_TRACE_POINTS
59 #include <trace/events/ipi.h>
62 * as from 2.5, kernels no longer have an init_tasks structure
63 * so we need some other way of telling a new secondary core
64 * where to place its SVC stack
66 struct secondary_data secondary_data
;
67 /* Number of CPUs which aren't online, but looping in kernel text. */
68 int cpus_stuck_in_kernel
;
79 #ifdef CONFIG_ARM64_VHE
81 /* Whether the boot CPU is running in HYP mode or not*/
82 static bool boot_cpu_hyp_mode
;
84 static inline void save_boot_cpu_run_el(void)
86 boot_cpu_hyp_mode
= is_kernel_in_hyp_mode();
89 static inline bool is_boot_cpu_in_hyp_mode(void)
91 return boot_cpu_hyp_mode
;
95 * Verify that a secondary CPU is running the kernel at the same
96 * EL as that of the boot CPU.
98 void verify_cpu_run_el(void)
100 bool in_el2
= is_kernel_in_hyp_mode();
101 bool boot_cpu_el2
= is_boot_cpu_in_hyp_mode();
103 if (in_el2
^ boot_cpu_el2
) {
104 pr_crit("CPU%d: mismatched Exception Level(EL%d) with boot CPU(EL%d)\n",
107 boot_cpu_el2
? 2 : 1);
113 static inline void save_boot_cpu_run_el(void) {}
116 #ifdef CONFIG_HOTPLUG_CPU
117 static int op_cpu_kill(unsigned int cpu
);
119 static inline int op_cpu_kill(unsigned int cpu
)
127 * Boot a secondary CPU, and assign it the specified idle task.
128 * This also gives us the initial stack to use for this CPU.
130 static int boot_secondary(unsigned int cpu
, struct task_struct
*idle
)
132 if (cpu_ops
[cpu
]->cpu_boot
)
133 return cpu_ops
[cpu
]->cpu_boot(cpu
);
138 static DECLARE_COMPLETION(cpu_running
);
140 int __cpu_up(unsigned int cpu
, struct task_struct
*idle
)
146 * We need to tell the secondary core where to find its stack and the
149 secondary_data
.stack
= task_stack_page(idle
) + THREAD_START_SP
;
150 update_cpu_boot_status(CPU_MMU_OFF
);
151 __flush_dcache_area(&secondary_data
, sizeof(secondary_data
));
154 * Now bring the CPU into our world.
156 ret
= boot_secondary(cpu
, idle
);
159 * CPU was successfully started, wait for it to come online or
162 wait_for_completion_timeout(&cpu_running
,
163 msecs_to_jiffies(1000));
165 if (!cpu_online(cpu
)) {
166 pr_crit("CPU%u: failed to come online\n", cpu
);
170 pr_err("CPU%u: failed to boot: %d\n", cpu
, ret
);
173 secondary_data
.stack
= NULL
;
174 status
= READ_ONCE(secondary_data
.status
);
177 if (status
== CPU_MMU_OFF
)
178 status
= READ_ONCE(__early_cpu_boot_status
);
182 pr_err("CPU%u: failed in unknown state : 0x%lx\n",
186 if (!op_cpu_kill(cpu
)) {
187 pr_crit("CPU%u: died during early boot\n", cpu
);
191 pr_crit("CPU%u: may not have shut down cleanly\n", cpu
);
192 case CPU_STUCK_IN_KERNEL
:
193 pr_crit("CPU%u: is stuck in kernel\n", cpu
);
194 cpus_stuck_in_kernel
++;
196 case CPU_PANIC_KERNEL
:
197 panic("CPU%u detected unsupported configuration\n", cpu
);
204 static void smp_store_cpu_info(unsigned int cpuid
)
206 store_cpu_topology(cpuid
);
207 numa_store_cpu_info(cpuid
);
211 * This is the secondary CPU boot entry. We're using this CPUs
212 * idle thread stack, but a set of temporary page tables.
214 asmlinkage
void secondary_start_kernel(void)
216 struct mm_struct
*mm
= &init_mm
;
217 unsigned int cpu
= smp_processor_id();
220 * All kernel threads share the same mm context; grab a
221 * reference and switch to it.
223 atomic_inc(&mm
->mm_count
);
224 current
->active_mm
= mm
;
226 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
229 * TTBR0 is only used for the identity mapping at this stage. Make it
230 * point to zero page to avoid speculatively fetching new entries.
232 cpu_uninstall_idmap();
235 trace_hardirqs_off();
238 * If the system has established the capabilities, make sure
239 * this CPU ticks all of those. If it doesn't, the CPU will
240 * fail to come online.
242 verify_local_cpu_capabilities();
244 if (cpu_ops
[cpu
]->cpu_postboot
)
245 cpu_ops
[cpu
]->cpu_postboot();
248 * Log the CPU info before it is marked online and might get read.
253 * Enable GIC and timers.
255 notify_cpu_starting(cpu
);
257 smp_store_cpu_info(cpu
);
260 * OK, now it's safe to let the boot CPU continue. Wait for
261 * the CPU migration code to notice that the CPU is online
262 * before we continue.
264 pr_info("CPU%u: Booted secondary processor [%08x]\n",
265 cpu
, read_cpuid_id());
266 update_cpu_boot_status(CPU_BOOT_SUCCESS
);
267 set_cpu_online(cpu
, true);
268 complete(&cpu_running
);
272 local_async_enable();
275 * OK, it's off to the idle thread for us
277 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE
);
280 #ifdef CONFIG_HOTPLUG_CPU
281 static int op_cpu_disable(unsigned int cpu
)
284 * If we don't have a cpu_die method, abort before we reach the point
285 * of no return. CPU0 may not have an cpu_ops, so test for it.
287 if (!cpu_ops
[cpu
] || !cpu_ops
[cpu
]->cpu_die
)
291 * We may need to abort a hot unplug for some other mechanism-specific
294 if (cpu_ops
[cpu
]->cpu_disable
)
295 return cpu_ops
[cpu
]->cpu_disable(cpu
);
301 * __cpu_disable runs on the processor to be shutdown.
303 int __cpu_disable(void)
305 unsigned int cpu
= smp_processor_id();
308 ret
= op_cpu_disable(cpu
);
313 * Take this CPU offline. Once we clear this, we can't return,
314 * and we must not schedule until we're ready to give up the cpu.
316 set_cpu_online(cpu
, false);
319 * OK - migrate IRQs away from this CPU
321 irq_migrate_all_off_this_cpu();
326 static int op_cpu_kill(unsigned int cpu
)
329 * If we have no means of synchronising with the dying CPU, then assume
330 * that it is really dead. We can only wait for an arbitrary length of
331 * time and hope that it's dead, so let's skip the wait and just hope.
333 if (!cpu_ops
[cpu
]->cpu_kill
)
336 return cpu_ops
[cpu
]->cpu_kill(cpu
);
340 * called on the thread which is asking for a CPU to be shutdown -
341 * waits until shutdown has completed, or it is timed out.
343 void __cpu_die(unsigned int cpu
)
347 if (!cpu_wait_death(cpu
, 5)) {
348 pr_crit("CPU%u: cpu didn't die\n", cpu
);
351 pr_notice("CPU%u: shutdown\n", cpu
);
354 * Now that the dying CPU is beyond the point of no return w.r.t.
355 * in-kernel synchronisation, try to get the firwmare to help us to
356 * verify that it has really left the kernel before we consider
357 * clobbering anything it might still be using.
359 err
= op_cpu_kill(cpu
);
361 pr_warn("CPU%d may not have shut down cleanly: %d\n",
366 * Called from the idle thread for the CPU which has been shutdown.
368 * Note that we disable IRQs here, but do not re-enable them
369 * before returning to the caller. This is also the behaviour
370 * of the other hotplug-cpu capable cores, so presumably coming
371 * out of idle fixes this.
375 unsigned int cpu
= smp_processor_id();
381 /* Tell __cpu_die() that this CPU is now safe to dispose of */
382 (void)cpu_report_death();
385 * Actually shutdown the CPU. This must never fail. The specific hotplug
386 * mechanism must perform all required cache maintenance to ensure that
387 * no dirty lines are lost in the process of shutting down the CPU.
389 cpu_ops
[cpu
]->cpu_die(cpu
);
396 * Kill the calling secondary CPU, early in bringup before it is turned
399 void cpu_die_early(void)
401 int cpu
= smp_processor_id();
403 pr_crit("CPU%d: will not boot\n", cpu
);
405 /* Mark this CPU absent */
406 set_cpu_present(cpu
, 0);
408 #ifdef CONFIG_HOTPLUG_CPU
409 update_cpu_boot_status(CPU_KILL_ME
);
410 /* Check if we can park ourselves */
411 if (cpu_ops
[cpu
] && cpu_ops
[cpu
]->cpu_die
)
412 cpu_ops
[cpu
]->cpu_die(cpu
);
414 update_cpu_boot_status(CPU_STUCK_IN_KERNEL
);
419 static void __init
hyp_mode_check(void)
421 if (is_hyp_mode_available())
422 pr_info("CPU: All CPU(s) started at EL2\n");
423 else if (is_hyp_mode_mismatched())
424 WARN_TAINT(1, TAINT_CPU_OUT_OF_SPEC
,
425 "CPU: CPUs started in inconsistent modes");
427 pr_info("CPU: All CPU(s) started at EL1\n");
430 void __init
smp_cpus_done(unsigned int max_cpus
)
432 pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
433 setup_cpu_features();
435 apply_alternatives_all();
438 void __init
smp_prepare_boot_cpu(void)
440 cpuinfo_store_boot_cpu();
441 save_boot_cpu_run_el();
442 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
445 static u64 __init
of_get_cpu_mpidr(struct device_node
*dn
)
451 * A cpu node with missing "reg" property is
452 * considered invalid to build a cpu_logical_map
455 cell
= of_get_property(dn
, "reg", NULL
);
457 pr_err("%s: missing reg property\n", dn
->full_name
);
461 hwid
= of_read_number(cell
, of_n_addr_cells(dn
));
463 * Non affinity bits must be set to 0 in the DT
465 if (hwid
& ~MPIDR_HWID_BITMASK
) {
466 pr_err("%s: invalid reg property\n", dn
->full_name
);
473 * Duplicate MPIDRs are a recipe for disaster. Scan all initialized
474 * entries and check for duplicates. If any is found just ignore the
475 * cpu. cpu_logical_map was initialized to INVALID_HWID to avoid
476 * matching valid MPIDR values.
478 static bool __init
is_mpidr_duplicate(unsigned int cpu
, u64 hwid
)
482 for (i
= 1; (i
< cpu
) && (i
< NR_CPUS
); i
++)
483 if (cpu_logical_map(i
) == hwid
)
489 * Initialize cpu operations for a logical cpu and
490 * set it in the possible mask on success
492 static int __init
smp_cpu_setup(int cpu
)
494 if (cpu_read_ops(cpu
))
497 if (cpu_ops
[cpu
]->cpu_init(cpu
))
500 set_cpu_possible(cpu
, true);
505 static bool bootcpu_valid __initdata
;
506 static unsigned int cpu_count
= 1;
510 * acpi_map_gic_cpu_interface - parse processor MADT entry
512 * Carry out sanity checks on MADT processor entry and initialize
513 * cpu_logical_map on success
516 acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt
*processor
)
518 u64 hwid
= processor
->arm_mpidr
;
520 if (!(processor
->flags
& ACPI_MADT_ENABLED
)) {
521 pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid
);
525 if (hwid
& ~MPIDR_HWID_BITMASK
|| hwid
== INVALID_HWID
) {
526 pr_err("skipping CPU entry with invalid MPIDR 0x%llx\n", hwid
);
530 if (is_mpidr_duplicate(cpu_count
, hwid
)) {
531 pr_err("duplicate CPU MPIDR 0x%llx in MADT\n", hwid
);
535 /* Check if GICC structure of boot CPU is available in the MADT */
536 if (cpu_logical_map(0) == hwid
) {
538 pr_err("duplicate boot CPU MPIDR: 0x%llx in MADT\n",
542 bootcpu_valid
= true;
546 if (cpu_count
>= NR_CPUS
)
549 /* map the logical cpu id to cpu MPIDR */
550 cpu_logical_map(cpu_count
) = hwid
;
553 * Set-up the ACPI parking protocol cpu entries
554 * while initializing the cpu_logical_map to
555 * avoid parsing MADT entries multiple times for
556 * nothing (ie a valid cpu_logical_map entry should
557 * contain a valid parking protocol data set to
558 * initialize the cpu if the parking protocol is
559 * the only available enable method).
561 acpi_set_mailbox_entry(cpu_count
, processor
);
567 acpi_parse_gic_cpu_interface(struct acpi_subtable_header
*header
,
568 const unsigned long end
)
570 struct acpi_madt_generic_interrupt
*processor
;
572 processor
= (struct acpi_madt_generic_interrupt
*)header
;
573 if (BAD_MADT_GICC_ENTRY(processor
, end
))
576 acpi_table_print_madt_entry(header
);
578 acpi_map_gic_cpu_interface(processor
);
583 #define acpi_table_parse_madt(...) do { } while (0)
587 * Enumerate the possible CPU set from the device tree and build the
588 * cpu logical map array containing MPIDR values related to logical
589 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
591 static void __init
of_parse_and_init_cpus(void)
593 struct device_node
*dn
= NULL
;
595 while ((dn
= of_find_node_by_type(dn
, "cpu"))) {
596 u64 hwid
= of_get_cpu_mpidr(dn
);
598 if (hwid
== INVALID_HWID
)
601 if (is_mpidr_duplicate(cpu_count
, hwid
)) {
602 pr_err("%s: duplicate cpu reg properties in the DT\n",
608 * The numbering scheme requires that the boot CPU
609 * must be assigned logical id 0. Record it so that
610 * the logical map built from DT is validated and can
613 if (hwid
== cpu_logical_map(0)) {
615 pr_err("%s: duplicate boot cpu reg property in DT\n",
620 bootcpu_valid
= true;
623 * cpu_logical_map has already been
624 * initialized and the boot cpu doesn't need
625 * the enable-method so continue without
631 if (cpu_count
>= NR_CPUS
)
634 pr_debug("cpu logical map 0x%llx\n", hwid
);
635 cpu_logical_map(cpu_count
) = hwid
;
637 early_map_cpu_to_node(cpu_count
, of_node_to_nid(dn
));
644 * Enumerate the possible CPU set from the device tree or ACPI and build the
645 * cpu logical map array containing MPIDR values related to logical
646 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
648 void __init
smp_init_cpus(void)
653 of_parse_and_init_cpus();
656 * do a walk of MADT to determine how many CPUs
657 * we have including disabled CPUs, and get information
658 * we need for SMP init
660 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT
,
661 acpi_parse_gic_cpu_interface
, 0);
663 if (cpu_count
> NR_CPUS
)
664 pr_warn("no. of cores (%d) greater than configured maximum of %d - clipping\n",
667 if (!bootcpu_valid
) {
668 pr_err("missing boot CPU MPIDR, not enabling secondaries\n");
673 * We need to set the cpu_logical_map entries before enabling
674 * the cpus so that cpu processor description entries (DT cpu nodes
675 * and ACPI MADT entries) can be retrieved by matching the cpu hwid
676 * with entries in cpu_logical_map while initializing the cpus.
677 * If the cpu set-up fails, invalidate the cpu_logical_map entry.
679 for (i
= 1; i
< NR_CPUS
; i
++) {
680 if (cpu_logical_map(i
) != INVALID_HWID
) {
681 if (smp_cpu_setup(i
))
682 cpu_logical_map(i
) = INVALID_HWID
;
687 void __init
smp_prepare_cpus(unsigned int max_cpus
)
694 smp_store_cpu_info(smp_processor_id());
697 * Initialise the present map (which describes the set of CPUs
698 * actually populated at the present time) and release the
699 * secondaries from the bootloader.
701 for_each_possible_cpu(cpu
) {
703 if (cpu
== smp_processor_id())
709 err
= cpu_ops
[cpu
]->cpu_prepare(cpu
);
713 set_cpu_present(cpu
, true);
717 void (*__smp_cross_call
)(const struct cpumask
*, unsigned int);
719 void __init
set_smp_cross_call(void (*fn
)(const struct cpumask
*, unsigned int))
721 __smp_cross_call
= fn
;
724 static const char *ipi_types
[NR_IPI
] __tracepoint_string
= {
725 #define S(x,s) [x] = s
726 S(IPI_RESCHEDULE
, "Rescheduling interrupts"),
727 S(IPI_CALL_FUNC
, "Function call interrupts"),
728 S(IPI_CPU_STOP
, "CPU stop interrupts"),
729 S(IPI_TIMER
, "Timer broadcast interrupts"),
730 S(IPI_IRQ_WORK
, "IRQ work interrupts"),
731 S(IPI_WAKEUP
, "CPU wake-up interrupts"),
734 static void smp_cross_call(const struct cpumask
*target
, unsigned int ipinr
)
736 trace_ipi_raise(target
, ipi_types
[ipinr
]);
737 __smp_cross_call(target
, ipinr
);
740 void show_ipi_list(struct seq_file
*p
, int prec
)
744 for (i
= 0; i
< NR_IPI
; i
++) {
745 seq_printf(p
, "%*s%u:%s", prec
- 1, "IPI", i
,
746 prec
>= 4 ? " " : "");
747 for_each_online_cpu(cpu
)
748 seq_printf(p
, "%10u ",
749 __get_irq_stat(cpu
, ipi_irqs
[i
]));
750 seq_printf(p
, " %s\n", ipi_types
[i
]);
754 u64
smp_irq_stat_cpu(unsigned int cpu
)
759 for (i
= 0; i
< NR_IPI
; i
++)
760 sum
+= __get_irq_stat(cpu
, ipi_irqs
[i
]);
765 void arch_send_call_function_ipi_mask(const struct cpumask
*mask
)
767 smp_cross_call(mask
, IPI_CALL_FUNC
);
770 void arch_send_call_function_single_ipi(int cpu
)
772 smp_cross_call(cpumask_of(cpu
), IPI_CALL_FUNC
);
775 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
776 void arch_send_wakeup_ipi_mask(const struct cpumask
*mask
)
778 smp_cross_call(mask
, IPI_WAKEUP
);
782 #ifdef CONFIG_IRQ_WORK
783 void arch_irq_work_raise(void)
785 if (__smp_cross_call
)
786 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK
);
791 * ipi_cpu_stop - handle IPI from smp_send_stop()
793 static void ipi_cpu_stop(unsigned int cpu
)
795 set_cpu_online(cpu
, false);
804 * Main handler for inter-processor interrupts
806 void handle_IPI(int ipinr
, struct pt_regs
*regs
)
808 unsigned int cpu
= smp_processor_id();
809 struct pt_regs
*old_regs
= set_irq_regs(regs
);
811 if ((unsigned)ipinr
< NR_IPI
) {
812 trace_ipi_entry_rcuidle(ipi_types
[ipinr
]);
813 __inc_irq_stat(cpu
, ipi_irqs
[ipinr
]);
823 generic_smp_call_function_interrupt();
833 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
836 tick_receive_broadcast();
841 #ifdef CONFIG_IRQ_WORK
849 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
851 WARN_ONCE(!acpi_parking_protocol_valid(cpu
),
852 "CPU%u: Wake-up IPI outside the ACPI parking protocol\n",
858 pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu
, ipinr
);
862 if ((unsigned)ipinr
< NR_IPI
)
863 trace_ipi_exit_rcuidle(ipi_types
[ipinr
]);
864 set_irq_regs(old_regs
);
867 void smp_send_reschedule(int cpu
)
869 smp_cross_call(cpumask_of(cpu
), IPI_RESCHEDULE
);
872 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
873 void tick_broadcast(const struct cpumask
*mask
)
875 smp_cross_call(mask
, IPI_TIMER
);
879 void smp_send_stop(void)
881 unsigned long timeout
;
883 if (num_online_cpus() > 1) {
886 cpumask_copy(&mask
, cpu_online_mask
);
887 cpumask_clear_cpu(smp_processor_id(), &mask
);
889 if (system_state
== SYSTEM_BOOTING
||
890 system_state
== SYSTEM_RUNNING
)
891 pr_crit("SMP: stopping secondary CPUs\n");
892 smp_cross_call(&mask
, IPI_CPU_STOP
);
895 /* Wait up to one second for other CPUs to stop */
896 timeout
= USEC_PER_SEC
;
897 while (num_online_cpus() > 1 && timeout
--)
900 if (num_online_cpus() > 1)
901 pr_warning("SMP: failed to stop secondary CPUs %*pbl\n",
902 cpumask_pr_args(cpu_online_mask
));
908 int setup_profiling_timer(unsigned int multiplier
)