Commit | Line | Data |
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f87e4cac JF |
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 | * This does not handle HOTPLUG_CPU yet. | |
16 | */ | |
17 | #include <linux/sched.h> | |
18 | #include <linux/err.h> | |
19 | #include <linux/smp.h> | |
20 | ||
21 | #include <asm/paravirt.h> | |
22 | #include <asm/desc.h> | |
23 | #include <asm/pgtable.h> | |
24 | #include <asm/cpu.h> | |
25 | ||
26 | #include <xen/interface/xen.h> | |
27 | #include <xen/interface/vcpu.h> | |
28 | ||
29 | #include <asm/xen/interface.h> | |
30 | #include <asm/xen/hypercall.h> | |
31 | ||
32 | #include <xen/page.h> | |
33 | #include <xen/events.h> | |
34 | ||
35 | #include "xen-ops.h" | |
36 | #include "mmu.h" | |
37 | ||
38 | static cpumask_t cpu_initialized_map; | |
39 | static DEFINE_PER_CPU(int, resched_irq); | |
40 | static DEFINE_PER_CPU(int, callfunc_irq); | |
41 | ||
42 | /* | |
43 | * Structure and data for smp_call_function(). This is designed to minimise | |
44 | * static memory requirements. It also looks cleaner. | |
45 | */ | |
46 | static DEFINE_SPINLOCK(call_lock); | |
47 | ||
48 | struct call_data_struct { | |
49 | void (*func) (void *info); | |
50 | void *info; | |
51 | atomic_t started; | |
52 | atomic_t finished; | |
53 | int wait; | |
54 | }; | |
55 | ||
56 | static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id); | |
57 | ||
58 | static struct call_data_struct *call_data; | |
59 | ||
60 | /* | |
61 | * Reschedule call back. Nothing to do, | |
62 | * all the work is done automatically when | |
63 | * we return from the interrupt. | |
64 | */ | |
65 | static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id) | |
66 | { | |
67 | return IRQ_HANDLED; | |
68 | } | |
69 | ||
70 | static __cpuinit void cpu_bringup_and_idle(void) | |
71 | { | |
72 | int cpu = smp_processor_id(); | |
73 | ||
74 | cpu_init(); | |
75 | ||
76 | preempt_disable(); | |
77 | per_cpu(cpu_state, cpu) = CPU_ONLINE; | |
78 | ||
79 | xen_setup_cpu_clockevents(); | |
80 | ||
81 | /* We can take interrupts now: we're officially "up". */ | |
82 | local_irq_enable(); | |
83 | ||
84 | wmb(); /* make sure everything is out */ | |
85 | cpu_idle(); | |
86 | } | |
87 | ||
88 | static int xen_smp_intr_init(unsigned int cpu) | |
89 | { | |
90 | int rc; | |
91 | const char *resched_name, *callfunc_name; | |
92 | ||
93 | per_cpu(resched_irq, cpu) = per_cpu(callfunc_irq, cpu) = -1; | |
94 | ||
95 | resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu); | |
96 | rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR, | |
97 | cpu, | |
98 | xen_reschedule_interrupt, | |
99 | IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, | |
100 | resched_name, | |
101 | NULL); | |
102 | if (rc < 0) | |
103 | goto fail; | |
104 | per_cpu(resched_irq, cpu) = rc; | |
105 | ||
106 | callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu); | |
107 | rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR, | |
108 | cpu, | |
109 | xen_call_function_interrupt, | |
110 | IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, | |
111 | callfunc_name, | |
112 | NULL); | |
113 | if (rc < 0) | |
114 | goto fail; | |
115 | per_cpu(callfunc_irq, cpu) = rc; | |
116 | ||
117 | return 0; | |
118 | ||
119 | fail: | |
120 | if (per_cpu(resched_irq, cpu) >= 0) | |
121 | unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL); | |
122 | if (per_cpu(callfunc_irq, cpu) >= 0) | |
123 | unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL); | |
124 | return rc; | |
125 | } | |
126 | ||
127 | void __init xen_fill_possible_map(void) | |
128 | { | |
129 | int i, rc; | |
130 | ||
131 | for (i = 0; i < NR_CPUS; i++) { | |
132 | rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL); | |
133 | if (rc >= 0) | |
134 | cpu_set(i, cpu_possible_map); | |
135 | } | |
136 | } | |
137 | ||
138 | void __init xen_smp_prepare_boot_cpu(void) | |
139 | { | |
140 | int cpu; | |
141 | ||
142 | BUG_ON(smp_processor_id() != 0); | |
143 | native_smp_prepare_boot_cpu(); | |
144 | ||
f87e4cac JF |
145 | /* We've switched to the "real" per-cpu gdt, so make sure the |
146 | old memory can be recycled */ | |
147 | make_lowmem_page_readwrite(&per_cpu__gdt_page); | |
148 | ||
149 | for (cpu = 0; cpu < NR_CPUS; cpu++) { | |
d5a7430d | 150 | cpus_clear(per_cpu(cpu_sibling_map, cpu)); |
08357611 MT |
151 | /* |
152 | * cpu_core_map lives in a per cpu area that is cleared | |
153 | * when the per cpu array is allocated. | |
154 | * | |
155 | * cpus_clear(per_cpu(cpu_core_map, cpu)); | |
156 | */ | |
f87e4cac | 157 | } |
60223a32 JF |
158 | |
159 | xen_setup_vcpu_info_placement(); | |
f87e4cac JF |
160 | } |
161 | ||
162 | void __init xen_smp_prepare_cpus(unsigned int max_cpus) | |
163 | { | |
164 | unsigned cpu; | |
165 | ||
166 | for (cpu = 0; cpu < NR_CPUS; cpu++) { | |
d5a7430d | 167 | cpus_clear(per_cpu(cpu_sibling_map, cpu)); |
08357611 MT |
168 | /* |
169 | * cpu_core_ map will be zeroed when the per | |
170 | * cpu area is allocated. | |
171 | * | |
172 | * cpus_clear(per_cpu(cpu_core_map, cpu)); | |
173 | */ | |
f87e4cac JF |
174 | } |
175 | ||
176 | smp_store_cpu_info(0); | |
177 | set_cpu_sibling_map(0); | |
178 | ||
179 | if (xen_smp_intr_init(0)) | |
180 | BUG(); | |
181 | ||
182 | cpu_initialized_map = cpumask_of_cpu(0); | |
183 | ||
184 | /* Restrict the possible_map according to max_cpus. */ | |
185 | while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) { | |
186 | for (cpu = NR_CPUS-1; !cpu_isset(cpu, cpu_possible_map); cpu--) | |
187 | continue; | |
188 | cpu_clear(cpu, cpu_possible_map); | |
189 | } | |
190 | ||
191 | for_each_possible_cpu (cpu) { | |
192 | struct task_struct *idle; | |
193 | ||
194 | if (cpu == 0) | |
195 | continue; | |
196 | ||
197 | idle = fork_idle(cpu); | |
198 | if (IS_ERR(idle)) | |
199 | panic("failed fork for CPU %d", cpu); | |
200 | ||
201 | cpu_set(cpu, cpu_present_map); | |
202 | } | |
203 | ||
204 | //init_xenbus_allowed_cpumask(); | |
205 | } | |
206 | ||
207 | static __cpuinit int | |
208 | cpu_initialize_context(unsigned int cpu, struct task_struct *idle) | |
209 | { | |
210 | struct vcpu_guest_context *ctxt; | |
211 | struct gdt_page *gdt = &per_cpu(gdt_page, cpu); | |
212 | ||
213 | if (cpu_test_and_set(cpu, cpu_initialized_map)) | |
214 | return 0; | |
215 | ||
216 | ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL); | |
217 | if (ctxt == NULL) | |
218 | return -ENOMEM; | |
219 | ||
220 | ctxt->flags = VGCF_IN_KERNEL; | |
221 | ctxt->user_regs.ds = __USER_DS; | |
222 | ctxt->user_regs.es = __USER_DS; | |
223 | ctxt->user_regs.fs = __KERNEL_PERCPU; | |
224 | ctxt->user_regs.gs = 0; | |
225 | ctxt->user_regs.ss = __KERNEL_DS; | |
226 | ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle; | |
227 | ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */ | |
228 | ||
229 | memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt)); | |
230 | ||
231 | xen_copy_trap_info(ctxt->trap_ctxt); | |
232 | ||
233 | ctxt->ldt_ents = 0; | |
234 | ||
235 | BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK); | |
236 | make_lowmem_page_readonly(gdt->gdt); | |
237 | ||
238 | ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt); | |
239 | ctxt->gdt_ents = ARRAY_SIZE(gdt->gdt); | |
240 | ||
241 | ctxt->user_regs.cs = __KERNEL_CS; | |
242 | ctxt->user_regs.esp = idle->thread.esp0 - sizeof(struct pt_regs); | |
243 | ||
244 | ctxt->kernel_ss = __KERNEL_DS; | |
245 | ctxt->kernel_sp = idle->thread.esp0; | |
246 | ||
247 | ctxt->event_callback_cs = __KERNEL_CS; | |
248 | ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback; | |
249 | ctxt->failsafe_callback_cs = __KERNEL_CS; | |
250 | ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback; | |
251 | ||
252 | per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir); | |
253 | ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir)); | |
254 | ||
255 | if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt)) | |
256 | BUG(); | |
257 | ||
258 | kfree(ctxt); | |
259 | return 0; | |
260 | } | |
261 | ||
262 | int __cpuinit xen_cpu_up(unsigned int cpu) | |
263 | { | |
264 | struct task_struct *idle = idle_task(cpu); | |
265 | int rc; | |
266 | ||
267 | #if 0 | |
268 | rc = cpu_up_check(cpu); | |
269 | if (rc) | |
270 | return rc; | |
271 | #endif | |
272 | ||
273 | init_gdt(cpu); | |
274 | per_cpu(current_task, cpu) = idle; | |
f87e4cac JF |
275 | irq_ctx_init(cpu); |
276 | xen_setup_timer(cpu); | |
277 | ||
278 | /* make sure interrupts start blocked */ | |
279 | per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1; | |
280 | ||
281 | rc = cpu_initialize_context(cpu, idle); | |
282 | if (rc) | |
283 | return rc; | |
284 | ||
285 | if (num_online_cpus() == 1) | |
286 | alternatives_smp_switch(1); | |
287 | ||
288 | rc = xen_smp_intr_init(cpu); | |
289 | if (rc) | |
290 | return rc; | |
291 | ||
292 | smp_store_cpu_info(cpu); | |
293 | set_cpu_sibling_map(cpu); | |
294 | /* This must be done before setting cpu_online_map */ | |
295 | wmb(); | |
296 | ||
297 | cpu_set(cpu, cpu_online_map); | |
298 | ||
299 | rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL); | |
300 | BUG_ON(rc); | |
301 | ||
302 | return 0; | |
303 | } | |
304 | ||
305 | void xen_smp_cpus_done(unsigned int max_cpus) | |
306 | { | |
307 | } | |
308 | ||
309 | static void stop_self(void *v) | |
310 | { | |
311 | int cpu = smp_processor_id(); | |
312 | ||
313 | /* make sure we're not pinning something down */ | |
314 | load_cr3(swapper_pg_dir); | |
315 | /* should set up a minimal gdt */ | |
316 | ||
317 | HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL); | |
318 | BUG(); | |
319 | } | |
320 | ||
321 | void xen_smp_send_stop(void) | |
322 | { | |
fefa629a | 323 | smp_call_function(stop_self, NULL, 0, 0); |
f87e4cac JF |
324 | } |
325 | ||
326 | void xen_smp_send_reschedule(int cpu) | |
327 | { | |
328 | xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR); | |
329 | } | |
330 | ||
331 | ||
332 | static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector) | |
333 | { | |
334 | unsigned cpu; | |
335 | ||
336 | cpus_and(mask, mask, cpu_online_map); | |
337 | ||
338 | for_each_cpu_mask(cpu, mask) | |
339 | xen_send_IPI_one(cpu, vector); | |
340 | } | |
341 | ||
342 | static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id) | |
343 | { | |
344 | void (*func) (void *info) = call_data->func; | |
345 | void *info = call_data->info; | |
346 | int wait = call_data->wait; | |
347 | ||
348 | /* | |
349 | * Notify initiating CPU that I've grabbed the data and am | |
350 | * about to execute the function | |
351 | */ | |
352 | mb(); | |
353 | atomic_inc(&call_data->started); | |
354 | /* | |
355 | * At this point the info structure may be out of scope unless wait==1 | |
356 | */ | |
357 | irq_enter(); | |
358 | (*func)(info); | |
359 | irq_exit(); | |
360 | ||
361 | if (wait) { | |
362 | mb(); /* commit everything before setting finished */ | |
363 | atomic_inc(&call_data->finished); | |
364 | } | |
365 | ||
366 | return IRQ_HANDLED; | |
367 | } | |
368 | ||
369 | int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *), | |
370 | void *info, int wait) | |
371 | { | |
372 | struct call_data_struct data; | |
373 | int cpus; | |
374 | ||
375 | /* Holding any lock stops cpus from going down. */ | |
376 | spin_lock(&call_lock); | |
377 | ||
378 | cpu_clear(smp_processor_id(), mask); | |
379 | ||
380 | cpus = cpus_weight(mask); | |
381 | if (!cpus) { | |
382 | spin_unlock(&call_lock); | |
383 | return 0; | |
384 | } | |
385 | ||
386 | /* Can deadlock when called with interrupts disabled */ | |
387 | WARN_ON(irqs_disabled()); | |
388 | ||
389 | data.func = func; | |
390 | data.info = info; | |
391 | atomic_set(&data.started, 0); | |
392 | data.wait = wait; | |
393 | if (wait) | |
394 | atomic_set(&data.finished, 0); | |
395 | ||
396 | call_data = &data; | |
397 | mb(); /* write everything before IPI */ | |
398 | ||
399 | /* Send a message to other CPUs and wait for them to respond */ | |
400 | xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR); | |
401 | ||
402 | /* Make sure other vcpus get a chance to run. | |
403 | XXX too severe? Maybe we should check the other CPU's states? */ | |
404 | HYPERVISOR_sched_op(SCHEDOP_yield, 0); | |
405 | ||
406 | /* Wait for response */ | |
407 | while (atomic_read(&data.started) != cpus || | |
408 | (wait && atomic_read(&data.finished) != cpus)) | |
409 | cpu_relax(); | |
410 | ||
411 | spin_unlock(&call_lock); | |
412 | ||
413 | return 0; | |
414 | } |