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08e875c1 CM |
1 | /* |
2 | * SMP initialisation and IPI support | |
3 | * Based on arch/arm/kernel/smp.c | |
4 | * | |
5 | * Copyright (C) 2012 ARM Ltd. | |
6 | * | |
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. | |
10 | * | |
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. | |
15 | * | |
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/>. | |
18 | */ | |
19 | ||
20 | #include <linux/delay.h> | |
21 | #include <linux/init.h> | |
22 | #include <linux/spinlock.h> | |
23 | #include <linux/sched.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/cache.h> | |
26 | #include <linux/profile.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/mm.h> | |
29 | #include <linux/err.h> | |
30 | #include <linux/cpu.h> | |
31 | #include <linux/smp.h> | |
32 | #include <linux/seq_file.h> | |
33 | #include <linux/irq.h> | |
34 | #include <linux/percpu.h> | |
35 | #include <linux/clockchips.h> | |
36 | #include <linux/completion.h> | |
37 | #include <linux/of.h> | |
38 | ||
39 | #include <asm/atomic.h> | |
40 | #include <asm/cacheflush.h> | |
41 | #include <asm/cputype.h> | |
42 | #include <asm/mmu_context.h> | |
43 | #include <asm/pgtable.h> | |
44 | #include <asm/pgalloc.h> | |
45 | #include <asm/processor.h> | |
46 | #include <asm/sections.h> | |
47 | #include <asm/tlbflush.h> | |
48 | #include <asm/ptrace.h> | |
08e875c1 CM |
49 | |
50 | /* | |
51 | * as from 2.5, kernels no longer have an init_tasks structure | |
52 | * so we need some other way of telling a new secondary core | |
53 | * where to place its SVC stack | |
54 | */ | |
55 | struct secondary_data secondary_data; | |
56 | volatile unsigned long secondary_holding_pen_release = -1; | |
57 | ||
58 | enum ipi_msg_type { | |
59 | IPI_RESCHEDULE, | |
60 | IPI_CALL_FUNC, | |
61 | IPI_CALL_FUNC_SINGLE, | |
62 | IPI_CPU_STOP, | |
63 | }; | |
64 | ||
65 | static DEFINE_RAW_SPINLOCK(boot_lock); | |
66 | ||
67 | /* | |
68 | * Write secondary_holding_pen_release in a way that is guaranteed to be | |
69 | * visible to all observers, irrespective of whether they're taking part | |
70 | * in coherency or not. This is necessary for the hotplug code to work | |
71 | * reliably. | |
72 | */ | |
73 | static void __cpuinit write_pen_release(int val) | |
74 | { | |
75 | void *start = (void *)&secondary_holding_pen_release; | |
76 | unsigned long size = sizeof(secondary_holding_pen_release); | |
77 | ||
78 | secondary_holding_pen_release = val; | |
79 | __flush_dcache_area(start, size); | |
80 | } | |
81 | ||
82 | /* | |
83 | * Boot a secondary CPU, and assign it the specified idle task. | |
84 | * This also gives us the initial stack to use for this CPU. | |
85 | */ | |
86 | static int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) | |
87 | { | |
88 | unsigned long timeout; | |
89 | ||
90 | /* | |
91 | * Set synchronisation state between this boot processor | |
92 | * and the secondary one | |
93 | */ | |
94 | raw_spin_lock(&boot_lock); | |
95 | ||
96 | /* | |
97 | * Update the pen release flag. | |
98 | */ | |
99 | write_pen_release(cpu); | |
100 | ||
101 | /* | |
102 | * Send an event, causing the secondaries to read pen_release. | |
103 | */ | |
104 | sev(); | |
105 | ||
106 | timeout = jiffies + (1 * HZ); | |
107 | while (time_before(jiffies, timeout)) { | |
108 | if (secondary_holding_pen_release == -1UL) | |
109 | break; | |
110 | udelay(10); | |
111 | } | |
112 | ||
113 | /* | |
114 | * Now the secondary core is starting up let it run its | |
115 | * calibrations, then wait for it to finish | |
116 | */ | |
117 | raw_spin_unlock(&boot_lock); | |
118 | ||
119 | return secondary_holding_pen_release != -1 ? -ENOSYS : 0; | |
120 | } | |
121 | ||
122 | static DECLARE_COMPLETION(cpu_running); | |
123 | ||
124 | int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle) | |
125 | { | |
126 | int ret; | |
127 | ||
128 | /* | |
129 | * We need to tell the secondary core where to find its stack and the | |
130 | * page tables. | |
131 | */ | |
132 | secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; | |
133 | __flush_dcache_area(&secondary_data, sizeof(secondary_data)); | |
134 | ||
135 | /* | |
136 | * Now bring the CPU into our world. | |
137 | */ | |
138 | ret = boot_secondary(cpu, idle); | |
139 | if (ret == 0) { | |
140 | /* | |
141 | * CPU was successfully started, wait for it to come online or | |
142 | * time out. | |
143 | */ | |
144 | wait_for_completion_timeout(&cpu_running, | |
145 | msecs_to_jiffies(1000)); | |
146 | ||
147 | if (!cpu_online(cpu)) { | |
148 | pr_crit("CPU%u: failed to come online\n", cpu); | |
149 | ret = -EIO; | |
150 | } | |
151 | } else { | |
152 | pr_err("CPU%u: failed to boot: %d\n", cpu, ret); | |
153 | } | |
154 | ||
155 | secondary_data.stack = NULL; | |
156 | ||
157 | return ret; | |
158 | } | |
159 | ||
160 | /* | |
161 | * This is the secondary CPU boot entry. We're using this CPUs | |
162 | * idle thread stack, but a set of temporary page tables. | |
163 | */ | |
164 | asmlinkage void __cpuinit secondary_start_kernel(void) | |
165 | { | |
166 | struct mm_struct *mm = &init_mm; | |
167 | unsigned int cpu = smp_processor_id(); | |
168 | ||
169 | printk("CPU%u: Booted secondary processor\n", cpu); | |
170 | ||
171 | /* | |
172 | * All kernel threads share the same mm context; grab a | |
173 | * reference and switch to it. | |
174 | */ | |
175 | atomic_inc(&mm->mm_count); | |
176 | current->active_mm = mm; | |
177 | cpumask_set_cpu(cpu, mm_cpumask(mm)); | |
178 | ||
179 | /* | |
180 | * TTBR0 is only used for the identity mapping at this stage. Make it | |
181 | * point to zero page to avoid speculatively fetching new entries. | |
182 | */ | |
183 | cpu_set_reserved_ttbr0(); | |
184 | flush_tlb_all(); | |
185 | ||
186 | preempt_disable(); | |
187 | trace_hardirqs_off(); | |
188 | ||
189 | /* | |
190 | * Let the primary processor know we're out of the | |
191 | * pen, then head off into the C entry point | |
192 | */ | |
193 | write_pen_release(-1); | |
194 | ||
195 | /* | |
196 | * Synchronise with the boot thread. | |
197 | */ | |
198 | raw_spin_lock(&boot_lock); | |
199 | raw_spin_unlock(&boot_lock); | |
200 | ||
201 | /* | |
202 | * Enable local interrupts. | |
203 | */ | |
204 | notify_cpu_starting(cpu); | |
205 | local_irq_enable(); | |
206 | local_fiq_enable(); | |
207 | ||
208 | /* | |
209 | * OK, now it's safe to let the boot CPU continue. Wait for | |
210 | * the CPU migration code to notice that the CPU is online | |
211 | * before we continue. | |
212 | */ | |
213 | set_cpu_online(cpu, true); | |
b3770b32 | 214 | complete(&cpu_running); |
08e875c1 CM |
215 | |
216 | /* | |
217 | * OK, it's off to the idle thread for us | |
218 | */ | |
219 | cpu_idle(); | |
220 | } | |
221 | ||
222 | void __init smp_cpus_done(unsigned int max_cpus) | |
223 | { | |
224 | unsigned long bogosum = loops_per_jiffy * num_online_cpus(); | |
225 | ||
226 | pr_info("SMP: Total of %d processors activated (%lu.%02lu BogoMIPS).\n", | |
227 | num_online_cpus(), bogosum / (500000/HZ), | |
228 | (bogosum / (5000/HZ)) % 100); | |
229 | } | |
230 | ||
231 | void __init smp_prepare_boot_cpu(void) | |
232 | { | |
233 | } | |
234 | ||
235 | static void (*smp_cross_call)(const struct cpumask *, unsigned int); | |
236 | static phys_addr_t cpu_release_addr[NR_CPUS]; | |
237 | ||
238 | /* | |
239 | * Enumerate the possible CPU set from the device tree. | |
240 | */ | |
241 | void __init smp_init_cpus(void) | |
242 | { | |
243 | const char *enable_method; | |
244 | struct device_node *dn = NULL; | |
245 | int cpu = 0; | |
246 | ||
247 | while ((dn = of_find_node_by_type(dn, "cpu"))) { | |
248 | if (cpu >= NR_CPUS) | |
249 | goto next; | |
250 | ||
251 | /* | |
252 | * We currently support only the "spin-table" enable-method. | |
253 | */ | |
254 | enable_method = of_get_property(dn, "enable-method", NULL); | |
255 | if (!enable_method || strcmp(enable_method, "spin-table")) { | |
256 | pr_err("CPU %d: missing or invalid enable-method property: %s\n", | |
257 | cpu, enable_method); | |
258 | goto next; | |
259 | } | |
260 | ||
261 | /* | |
262 | * Determine the address from which the CPU is polling. | |
263 | */ | |
264 | if (of_property_read_u64(dn, "cpu-release-addr", | |
265 | &cpu_release_addr[cpu])) { | |
266 | pr_err("CPU %d: missing or invalid cpu-release-addr property\n", | |
267 | cpu); | |
268 | goto next; | |
269 | } | |
270 | ||
271 | set_cpu_possible(cpu, true); | |
272 | next: | |
273 | cpu++; | |
274 | } | |
275 | ||
276 | /* sanity check */ | |
277 | if (cpu > NR_CPUS) | |
278 | pr_warning("no. of cores (%d) greater than configured maximum of %d - clipping\n", | |
279 | cpu, NR_CPUS); | |
280 | } | |
281 | ||
282 | void __init smp_prepare_cpus(unsigned int max_cpus) | |
283 | { | |
284 | int cpu; | |
285 | void **release_addr; | |
286 | unsigned int ncores = num_possible_cpus(); | |
287 | ||
288 | /* | |
289 | * are we trying to boot more cores than exist? | |
290 | */ | |
291 | if (max_cpus > ncores) | |
292 | max_cpus = ncores; | |
293 | ||
294 | /* | |
295 | * Initialise the present map (which describes the set of CPUs | |
296 | * actually populated at the present time) and release the | |
297 | * secondaries from the bootloader. | |
298 | */ | |
299 | for_each_possible_cpu(cpu) { | |
300 | if (max_cpus == 0) | |
301 | break; | |
302 | ||
303 | if (!cpu_release_addr[cpu]) | |
304 | continue; | |
305 | ||
306 | release_addr = __va(cpu_release_addr[cpu]); | |
307 | release_addr[0] = (void *)__pa(secondary_holding_pen); | |
308 | __flush_dcache_area(release_addr, sizeof(release_addr[0])); | |
309 | ||
310 | set_cpu_present(cpu, true); | |
311 | max_cpus--; | |
312 | } | |
313 | ||
314 | /* | |
315 | * Send an event to wake up the secondaries. | |
316 | */ | |
317 | sev(); | |
318 | } | |
319 | ||
320 | ||
321 | void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int)) | |
322 | { | |
323 | smp_cross_call = fn; | |
324 | } | |
325 | ||
326 | void arch_send_call_function_ipi_mask(const struct cpumask *mask) | |
327 | { | |
328 | smp_cross_call(mask, IPI_CALL_FUNC); | |
329 | } | |
330 | ||
331 | void arch_send_call_function_single_ipi(int cpu) | |
332 | { | |
333 | smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE); | |
334 | } | |
335 | ||
336 | static const char *ipi_types[NR_IPI] = { | |
337 | #define S(x,s) [x - IPI_RESCHEDULE] = s | |
338 | S(IPI_RESCHEDULE, "Rescheduling interrupts"), | |
339 | S(IPI_CALL_FUNC, "Function call interrupts"), | |
340 | S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"), | |
341 | S(IPI_CPU_STOP, "CPU stop interrupts"), | |
342 | }; | |
343 | ||
344 | void show_ipi_list(struct seq_file *p, int prec) | |
345 | { | |
346 | unsigned int cpu, i; | |
347 | ||
348 | for (i = 0; i < NR_IPI; i++) { | |
349 | seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i + IPI_RESCHEDULE, | |
350 | prec >= 4 ? " " : ""); | |
351 | for_each_present_cpu(cpu) | |
352 | seq_printf(p, "%10u ", | |
353 | __get_irq_stat(cpu, ipi_irqs[i])); | |
354 | seq_printf(p, " %s\n", ipi_types[i]); | |
355 | } | |
356 | } | |
357 | ||
358 | u64 smp_irq_stat_cpu(unsigned int cpu) | |
359 | { | |
360 | u64 sum = 0; | |
361 | int i; | |
362 | ||
363 | for (i = 0; i < NR_IPI; i++) | |
364 | sum += __get_irq_stat(cpu, ipi_irqs[i]); | |
365 | ||
366 | return sum; | |
367 | } | |
368 | ||
369 | static DEFINE_RAW_SPINLOCK(stop_lock); | |
370 | ||
371 | /* | |
372 | * ipi_cpu_stop - handle IPI from smp_send_stop() | |
373 | */ | |
374 | static void ipi_cpu_stop(unsigned int cpu) | |
375 | { | |
376 | if (system_state == SYSTEM_BOOTING || | |
377 | system_state == SYSTEM_RUNNING) { | |
378 | raw_spin_lock(&stop_lock); | |
379 | pr_crit("CPU%u: stopping\n", cpu); | |
380 | dump_stack(); | |
381 | raw_spin_unlock(&stop_lock); | |
382 | } | |
383 | ||
384 | set_cpu_online(cpu, false); | |
385 | ||
386 | local_fiq_disable(); | |
387 | local_irq_disable(); | |
388 | ||
389 | while (1) | |
390 | cpu_relax(); | |
391 | } | |
392 | ||
393 | /* | |
394 | * Main handler for inter-processor interrupts | |
395 | */ | |
396 | void handle_IPI(int ipinr, struct pt_regs *regs) | |
397 | { | |
398 | unsigned int cpu = smp_processor_id(); | |
399 | struct pt_regs *old_regs = set_irq_regs(regs); | |
400 | ||
401 | if (ipinr >= IPI_RESCHEDULE && ipinr < IPI_RESCHEDULE + NR_IPI) | |
402 | __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_RESCHEDULE]); | |
403 | ||
404 | switch (ipinr) { | |
405 | case IPI_RESCHEDULE: | |
406 | scheduler_ipi(); | |
407 | break; | |
408 | ||
409 | case IPI_CALL_FUNC: | |
410 | irq_enter(); | |
411 | generic_smp_call_function_interrupt(); | |
412 | irq_exit(); | |
413 | break; | |
414 | ||
415 | case IPI_CALL_FUNC_SINGLE: | |
416 | irq_enter(); | |
417 | generic_smp_call_function_single_interrupt(); | |
418 | irq_exit(); | |
419 | break; | |
420 | ||
421 | case IPI_CPU_STOP: | |
422 | irq_enter(); | |
423 | ipi_cpu_stop(cpu); | |
424 | irq_exit(); | |
425 | break; | |
426 | ||
427 | default: | |
428 | pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr); | |
429 | break; | |
430 | } | |
431 | set_irq_regs(old_regs); | |
432 | } | |
433 | ||
434 | void smp_send_reschedule(int cpu) | |
435 | { | |
436 | smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); | |
437 | } | |
438 | ||
439 | void smp_send_stop(void) | |
440 | { | |
441 | unsigned long timeout; | |
442 | ||
443 | if (num_online_cpus() > 1) { | |
444 | cpumask_t mask; | |
445 | ||
446 | cpumask_copy(&mask, cpu_online_mask); | |
447 | cpu_clear(smp_processor_id(), mask); | |
448 | ||
449 | smp_cross_call(&mask, IPI_CPU_STOP); | |
450 | } | |
451 | ||
452 | /* Wait up to one second for other CPUs to stop */ | |
453 | timeout = USEC_PER_SEC; | |
454 | while (num_online_cpus() > 1 && timeout--) | |
455 | udelay(1); | |
456 | ||
457 | if (num_online_cpus() > 1) | |
458 | pr_warning("SMP: failed to stop secondary CPUs\n"); | |
459 | } | |
460 | ||
461 | /* | |
462 | * not supported here | |
463 | */ | |
464 | int setup_profiling_timer(unsigned int multiplier) | |
465 | { | |
466 | return -EINVAL; | |
467 | } |