Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas...
[linux-2.6.git] / arch / x86 / xen / smp.c
1 /*
2  * Xen SMP support
3  *
4  * This file implements the Xen versions of smp_ops.  SMP under Xen is
5  * very straightforward.  Bringing a CPU up is simply a matter of
6  * loading its initial context and setting it running.
7  *
8  * IPIs are handled through the Xen event mechanism.
9  *
10  * Because virtual CPUs can be scheduled onto any real CPU, there's no
11  * useful topology information for the kernel to make use of.  As a
12  * result, all CPUs are treated as if they're single-core and
13  * single-threaded.
14  */
15 #include <linux/sched.h>
16 #include <linux/err.h>
17 #include <linux/slab.h>
18 #include <linux/smp.h>
19
20 #include <asm/paravirt.h>
21 #include <asm/desc.h>
22 #include <asm/pgtable.h>
23 #include <asm/cpu.h>
24
25 #include <xen/interface/xen.h>
26 #include <xen/interface/vcpu.h>
27
28 #include <asm/xen/interface.h>
29 #include <asm/xen/hypercall.h>
30
31 #include <xen/xen.h>
32 #include <xen/page.h>
33 #include <xen/events.h>
34
35 #include "xen-ops.h"
36 #include "mmu.h"
37
38 cpumask_var_t xen_cpu_initialized_map;
39
40 static DEFINE_PER_CPU(int, xen_resched_irq);
41 static DEFINE_PER_CPU(int, xen_callfunc_irq);
42 static DEFINE_PER_CPU(int, xen_callfuncsingle_irq);
43 static DEFINE_PER_CPU(int, xen_debug_irq) = -1;
44
45 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
46 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
47
48 /*
49  * Reschedule call back. Nothing to do,
50  * all the work is done automatically when
51  * we return from the interrupt.
52  */
53 static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
54 {
55         inc_irq_stat(irq_resched_count);
56
57         return IRQ_HANDLED;
58 }
59
60 static void __cpuinit cpu_bringup(void)
61 {
62         int cpu = smp_processor_id();
63
64         cpu_init();
65         touch_softlockup_watchdog();
66         preempt_disable();
67
68         xen_enable_sysenter();
69         xen_enable_syscall();
70
71         cpu = smp_processor_id();
72         smp_store_cpu_info(cpu);
73         cpu_data(cpu).x86_max_cores = 1;
74         set_cpu_sibling_map(cpu);
75
76         xen_setup_cpu_clockevents();
77
78         set_cpu_online(cpu, true);
79         percpu_write(cpu_state, CPU_ONLINE);
80         wmb();
81
82         /* We can take interrupts now: we're officially "up". */
83         local_irq_enable();
84
85         wmb();                  /* make sure everything is out */
86 }
87
88 static void __cpuinit cpu_bringup_and_idle(void)
89 {
90         cpu_bringup();
91         cpu_idle();
92 }
93
94 static int xen_smp_intr_init(unsigned int cpu)
95 {
96         int rc;
97         const char *resched_name, *callfunc_name, *debug_name;
98
99         resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
100         rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
101                                     cpu,
102                                     xen_reschedule_interrupt,
103                                     IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
104                                     resched_name,
105                                     NULL);
106         if (rc < 0)
107                 goto fail;
108         per_cpu(xen_resched_irq, cpu) = rc;
109
110         callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
111         rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
112                                     cpu,
113                                     xen_call_function_interrupt,
114                                     IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
115                                     callfunc_name,
116                                     NULL);
117         if (rc < 0)
118                 goto fail;
119         per_cpu(xen_callfunc_irq, cpu) = rc;
120
121         debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
122         rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
123                                      IRQF_DISABLED | IRQF_PERCPU | IRQF_NOBALANCING,
124                                      debug_name, NULL);
125         if (rc < 0)
126                 goto fail;
127         per_cpu(xen_debug_irq, cpu) = rc;
128
129         callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
130         rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
131                                     cpu,
132                                     xen_call_function_single_interrupt,
133                                     IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
134                                     callfunc_name,
135                                     NULL);
136         if (rc < 0)
137                 goto fail;
138         per_cpu(xen_callfuncsingle_irq, cpu) = rc;
139
140         return 0;
141
142  fail:
143         if (per_cpu(xen_resched_irq, cpu) >= 0)
144                 unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
145         if (per_cpu(xen_callfunc_irq, cpu) >= 0)
146                 unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
147         if (per_cpu(xen_debug_irq, cpu) >= 0)
148                 unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
149         if (per_cpu(xen_callfuncsingle_irq, cpu) >= 0)
150                 unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu),
151                                        NULL);
152
153         return rc;
154 }
155
156 static void __init xen_fill_possible_map(void)
157 {
158         int i, rc;
159
160         if (xen_initial_domain())
161                 return;
162
163         for (i = 0; i < nr_cpu_ids; i++) {
164                 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
165                 if (rc >= 0) {
166                         num_processors++;
167                         set_cpu_possible(i, true);
168                 }
169         }
170 }
171
172 static void __init xen_filter_cpu_maps(void)
173 {
174         int i, rc;
175
176         if (!xen_initial_domain())
177                 return;
178
179         num_processors = 0;
180         disabled_cpus = 0;
181         for (i = 0; i < nr_cpu_ids; i++) {
182                 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
183                 if (rc >= 0) {
184                         num_processors++;
185                         set_cpu_possible(i, true);
186                 } else {
187                         set_cpu_possible(i, false);
188                         set_cpu_present(i, false);
189                 }
190         }
191 }
192
193 static void __init xen_smp_prepare_boot_cpu(void)
194 {
195         BUG_ON(smp_processor_id() != 0);
196         native_smp_prepare_boot_cpu();
197
198         /* We've switched to the "real" per-cpu gdt, so make sure the
199            old memory can be recycled */
200         make_lowmem_page_readwrite(xen_initial_gdt);
201
202         xen_filter_cpu_maps();
203         xen_setup_vcpu_info_placement();
204 }
205
206 static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
207 {
208         unsigned cpu;
209
210         xen_init_lock_cpu(0);
211
212         smp_store_cpu_info(0);
213         cpu_data(0).x86_max_cores = 1;
214         set_cpu_sibling_map(0);
215
216         if (xen_smp_intr_init(0))
217                 BUG();
218
219         if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))
220                 panic("could not allocate xen_cpu_initialized_map\n");
221
222         cpumask_copy(xen_cpu_initialized_map, cpumask_of(0));
223
224         /* Restrict the possible_map according to max_cpus. */
225         while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
226                 for (cpu = nr_cpu_ids - 1; !cpu_possible(cpu); cpu--)
227                         continue;
228                 set_cpu_possible(cpu, false);
229         }
230
231         for_each_possible_cpu (cpu) {
232                 struct task_struct *idle;
233
234                 if (cpu == 0)
235                         continue;
236
237                 idle = fork_idle(cpu);
238                 if (IS_ERR(idle))
239                         panic("failed fork for CPU %d", cpu);
240
241                 set_cpu_present(cpu, true);
242         }
243 }
244
245 static int __cpuinit
246 cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
247 {
248         struct vcpu_guest_context *ctxt;
249         struct desc_struct *gdt;
250         unsigned long gdt_mfn;
251
252         if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
253                 return 0;
254
255         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
256         if (ctxt == NULL)
257                 return -ENOMEM;
258
259         gdt = get_cpu_gdt_table(cpu);
260
261         ctxt->flags = VGCF_IN_KERNEL;
262         ctxt->user_regs.ds = __USER_DS;
263         ctxt->user_regs.es = __USER_DS;
264         ctxt->user_regs.ss = __KERNEL_DS;
265 #ifdef CONFIG_X86_32
266         ctxt->user_regs.fs = __KERNEL_PERCPU;
267         ctxt->user_regs.gs = __KERNEL_STACK_CANARY;
268 #else
269         ctxt->gs_base_kernel = per_cpu_offset(cpu);
270 #endif
271         ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
272         ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
273
274         memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
275
276         xen_copy_trap_info(ctxt->trap_ctxt);
277
278         ctxt->ldt_ents = 0;
279
280         BUG_ON((unsigned long)gdt & ~PAGE_MASK);
281
282         gdt_mfn = arbitrary_virt_to_mfn(gdt);
283         make_lowmem_page_readonly(gdt);
284         make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
285
286         ctxt->gdt_frames[0] = gdt_mfn;
287         ctxt->gdt_ents      = GDT_ENTRIES;
288
289         ctxt->user_regs.cs = __KERNEL_CS;
290         ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
291
292         ctxt->kernel_ss = __KERNEL_DS;
293         ctxt->kernel_sp = idle->thread.sp0;
294
295 #ifdef CONFIG_X86_32
296         ctxt->event_callback_cs     = __KERNEL_CS;
297         ctxt->failsafe_callback_cs  = __KERNEL_CS;
298 #endif
299         ctxt->event_callback_eip    = (unsigned long)xen_hypervisor_callback;
300         ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
301
302         per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
303         ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
304
305         if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
306                 BUG();
307
308         kfree(ctxt);
309         return 0;
310 }
311
312 static int __cpuinit xen_cpu_up(unsigned int cpu)
313 {
314         struct task_struct *idle = idle_task(cpu);
315         int rc;
316
317         per_cpu(current_task, cpu) = idle;
318 #ifdef CONFIG_X86_32
319         irq_ctx_init(cpu);
320 #else
321         clear_tsk_thread_flag(idle, TIF_FORK);
322         per_cpu(kernel_stack, cpu) =
323                 (unsigned long)task_stack_page(idle) -
324                 KERNEL_STACK_OFFSET + THREAD_SIZE;
325 #endif
326         xen_setup_runstate_info(cpu);
327         xen_setup_timer(cpu);
328         xen_init_lock_cpu(cpu);
329
330         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
331
332         /* make sure interrupts start blocked */
333         per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
334
335         rc = cpu_initialize_context(cpu, idle);
336         if (rc)
337                 return rc;
338
339         if (num_online_cpus() == 1)
340                 alternatives_smp_switch(1);
341
342         rc = xen_smp_intr_init(cpu);
343         if (rc)
344                 return rc;
345
346         rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
347         BUG_ON(rc);
348
349         while(per_cpu(cpu_state, cpu) != CPU_ONLINE) {
350                 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
351                 barrier();
352         }
353
354         return 0;
355 }
356
357 static void xen_smp_cpus_done(unsigned int max_cpus)
358 {
359 }
360
361 #ifdef CONFIG_HOTPLUG_CPU
362 static int xen_cpu_disable(void)
363 {
364         unsigned int cpu = smp_processor_id();
365         if (cpu == 0)
366                 return -EBUSY;
367
368         cpu_disable_common();
369
370         load_cr3(swapper_pg_dir);
371         return 0;
372 }
373
374 static void xen_cpu_die(unsigned int cpu)
375 {
376         while (HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL)) {
377                 current->state = TASK_UNINTERRUPTIBLE;
378                 schedule_timeout(HZ/10);
379         }
380         unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
381         unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
382         unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
383         unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL);
384         xen_uninit_lock_cpu(cpu);
385         xen_teardown_timer(cpu);
386
387         if (num_online_cpus() == 1)
388                 alternatives_smp_switch(0);
389 }
390
391 static void __cpuinit xen_play_dead(void) /* used only with HOTPLUG_CPU */
392 {
393         play_dead_common();
394         HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
395         cpu_bringup();
396 }
397
398 #else /* !CONFIG_HOTPLUG_CPU */
399 static int xen_cpu_disable(void)
400 {
401         return -ENOSYS;
402 }
403
404 static void xen_cpu_die(unsigned int cpu)
405 {
406         BUG();
407 }
408
409 static void xen_play_dead(void)
410 {
411         BUG();
412 }
413
414 #endif
415 static void stop_self(void *v)
416 {
417         int cpu = smp_processor_id();
418
419         /* make sure we're not pinning something down */
420         load_cr3(swapper_pg_dir);
421         /* should set up a minimal gdt */
422
423         set_cpu_online(cpu, false);
424
425         HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
426         BUG();
427 }
428
429 static void xen_stop_other_cpus(int wait)
430 {
431         smp_call_function(stop_self, NULL, wait);
432 }
433
434 static void xen_smp_send_reschedule(int cpu)
435 {
436         xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
437 }
438
439 static void xen_send_IPI_mask(const struct cpumask *mask,
440                               enum ipi_vector vector)
441 {
442         unsigned cpu;
443
444         for_each_cpu_and(cpu, mask, cpu_online_mask)
445                 xen_send_IPI_one(cpu, vector);
446 }
447
448 static void xen_smp_send_call_function_ipi(const struct cpumask *mask)
449 {
450         int cpu;
451
452         xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
453
454         /* Make sure other vcpus get a chance to run if they need to. */
455         for_each_cpu(cpu, mask) {
456                 if (xen_vcpu_stolen(cpu)) {
457                         HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
458                         break;
459                 }
460         }
461 }
462
463 static void xen_smp_send_call_function_single_ipi(int cpu)
464 {
465         xen_send_IPI_mask(cpumask_of(cpu),
466                           XEN_CALL_FUNCTION_SINGLE_VECTOR);
467 }
468
469 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
470 {
471         irq_enter();
472         generic_smp_call_function_interrupt();
473         inc_irq_stat(irq_call_count);
474         irq_exit();
475
476         return IRQ_HANDLED;
477 }
478
479 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
480 {
481         irq_enter();
482         generic_smp_call_function_single_interrupt();
483         inc_irq_stat(irq_call_count);
484         irq_exit();
485
486         return IRQ_HANDLED;
487 }
488
489 static const struct smp_ops xen_smp_ops __initconst = {
490         .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
491         .smp_prepare_cpus = xen_smp_prepare_cpus,
492         .smp_cpus_done = xen_smp_cpus_done,
493
494         .cpu_up = xen_cpu_up,
495         .cpu_die = xen_cpu_die,
496         .cpu_disable = xen_cpu_disable,
497         .play_dead = xen_play_dead,
498
499         .stop_other_cpus = xen_stop_other_cpus,
500         .smp_send_reschedule = xen_smp_send_reschedule,
501
502         .send_call_func_ipi = xen_smp_send_call_function_ipi,
503         .send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
504 };
505
506 void __init xen_smp_init(void)
507 {
508         smp_ops = xen_smp_ops;
509         xen_fill_possible_map();
510         xen_init_spinlocks();
511 }
512
513 static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
514 {
515         native_smp_prepare_cpus(max_cpus);
516         WARN_ON(xen_smp_intr_init(0));
517
518         if (!xen_have_vector_callback)
519                 return;
520         xen_init_lock_cpu(0);
521         xen_init_spinlocks();
522 }
523
524 static int __cpuinit xen_hvm_cpu_up(unsigned int cpu)
525 {
526         int rc;
527         rc = native_cpu_up(cpu);
528         WARN_ON (xen_smp_intr_init(cpu));
529         return rc;
530 }
531
532 static void xen_hvm_cpu_die(unsigned int cpu)
533 {
534         unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
535         unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
536         unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
537         unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL);
538         native_cpu_die(cpu);
539 }
540
541 void __init xen_hvm_smp_init(void)
542 {
543         smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus;
544         smp_ops.smp_send_reschedule = xen_smp_send_reschedule;
545         smp_ops.cpu_up = xen_hvm_cpu_up;
546         smp_ops.cpu_die = xen_hvm_cpu_die;
547         smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi;
548         smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi;
549 }