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authorThomas Gleixner <tglx@linutronix.de>2007-10-11 05:16:51 -0400
committerThomas Gleixner <tglx@linutronix.de>2007-10-11 05:16:51 -0400
commit9702785a747aa27baf46ff504beab6528f21f2dd (patch)
treeab69d6f802f5b680c33999dc089e44982c74595d /arch/x86/xen/smp.c
parent334e621a01f86d5bc25e4f742e1eaae6e2d2a97a (diff)
i386: move xen
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/xen/smp.c')
-rw-r--r--arch/x86/xen/smp.c404
1 files changed, 404 insertions, 0 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
new file mode 100644
index 000000000000..557b8e24706a
--- /dev/null
+++ b/arch/x86/xen/smp.c
@@ -0,0 +1,404 @@
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
38static cpumask_t cpu_initialized_map;
39static DEFINE_PER_CPU(int, resched_irq);
40static 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 */
46static DEFINE_SPINLOCK(call_lock);
47
48struct call_data_struct {
49 void (*func) (void *info);
50 void *info;
51 atomic_t started;
52 atomic_t finished;
53 int wait;
54};
55
56static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
57
58static 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 */
65static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
66{
67 return IRQ_HANDLED;
68}
69
70static __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
88static 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
127void __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
138void __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
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++) {
150 cpus_clear(cpu_sibling_map[cpu]);
151 cpus_clear(cpu_core_map[cpu]);
152 }
153
154 xen_setup_vcpu_info_placement();
155}
156
157void __init xen_smp_prepare_cpus(unsigned int max_cpus)
158{
159 unsigned cpu;
160
161 for (cpu = 0; cpu < NR_CPUS; cpu++) {
162 cpus_clear(cpu_sibling_map[cpu]);
163 cpus_clear(cpu_core_map[cpu]);
164 }
165
166 smp_store_cpu_info(0);
167 set_cpu_sibling_map(0);
168
169 if (xen_smp_intr_init(0))
170 BUG();
171
172 cpu_initialized_map = cpumask_of_cpu(0);
173
174 /* Restrict the possible_map according to max_cpus. */
175 while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
176 for (cpu = NR_CPUS-1; !cpu_isset(cpu, cpu_possible_map); cpu--)
177 continue;
178 cpu_clear(cpu, cpu_possible_map);
179 }
180
181 for_each_possible_cpu (cpu) {
182 struct task_struct *idle;
183
184 if (cpu == 0)
185 continue;
186
187 idle = fork_idle(cpu);
188 if (IS_ERR(idle))
189 panic("failed fork for CPU %d", cpu);
190
191 cpu_set(cpu, cpu_present_map);
192 }
193
194 //init_xenbus_allowed_cpumask();
195}
196
197static __cpuinit int
198cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
199{
200 struct vcpu_guest_context *ctxt;
201 struct gdt_page *gdt = &per_cpu(gdt_page, cpu);
202
203 if (cpu_test_and_set(cpu, cpu_initialized_map))
204 return 0;
205
206 ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
207 if (ctxt == NULL)
208 return -ENOMEM;
209
210 ctxt->flags = VGCF_IN_KERNEL;
211 ctxt->user_regs.ds = __USER_DS;
212 ctxt->user_regs.es = __USER_DS;
213 ctxt->user_regs.fs = __KERNEL_PERCPU;
214 ctxt->user_regs.gs = 0;
215 ctxt->user_regs.ss = __KERNEL_DS;
216 ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
217 ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
218
219 memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
220
221 xen_copy_trap_info(ctxt->trap_ctxt);
222
223 ctxt->ldt_ents = 0;
224
225 BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK);
226 make_lowmem_page_readonly(gdt->gdt);
227
228 ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt);
229 ctxt->gdt_ents = ARRAY_SIZE(gdt->gdt);
230
231 ctxt->user_regs.cs = __KERNEL_CS;
232 ctxt->user_regs.esp = idle->thread.esp0 - sizeof(struct pt_regs);
233
234 ctxt->kernel_ss = __KERNEL_DS;
235 ctxt->kernel_sp = idle->thread.esp0;
236
237 ctxt->event_callback_cs = __KERNEL_CS;
238 ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback;
239 ctxt->failsafe_callback_cs = __KERNEL_CS;
240 ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
241
242 per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
243 ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
244
245 if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
246 BUG();
247
248 kfree(ctxt);
249 return 0;
250}
251
252int __cpuinit xen_cpu_up(unsigned int cpu)
253{
254 struct task_struct *idle = idle_task(cpu);
255 int rc;
256
257#if 0
258 rc = cpu_up_check(cpu);
259 if (rc)
260 return rc;
261#endif
262
263 init_gdt(cpu);
264 per_cpu(current_task, cpu) = idle;
265 irq_ctx_init(cpu);
266 xen_setup_timer(cpu);
267
268 /* make sure interrupts start blocked */
269 per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
270
271 rc = cpu_initialize_context(cpu, idle);
272 if (rc)
273 return rc;
274
275 if (num_online_cpus() == 1)
276 alternatives_smp_switch(1);
277
278 rc = xen_smp_intr_init(cpu);
279 if (rc)
280 return rc;
281
282 smp_store_cpu_info(cpu);
283 set_cpu_sibling_map(cpu);
284 /* This must be done before setting cpu_online_map */
285 wmb();
286
287 cpu_set(cpu, cpu_online_map);
288
289 rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
290 BUG_ON(rc);
291
292 return 0;
293}
294
295void xen_smp_cpus_done(unsigned int max_cpus)
296{
297}
298
299static void stop_self(void *v)
300{
301 int cpu = smp_processor_id();
302
303 /* make sure we're not pinning something down */
304 load_cr3(swapper_pg_dir);
305 /* should set up a minimal gdt */
306
307 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
308 BUG();
309}
310
311void xen_smp_send_stop(void)
312{
313 smp_call_function(stop_self, NULL, 0, 0);
314}
315
316void xen_smp_send_reschedule(int cpu)
317{
318 xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
319}
320
321
322static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector)
323{
324 unsigned cpu;
325
326 cpus_and(mask, mask, cpu_online_map);
327
328 for_each_cpu_mask(cpu, mask)
329 xen_send_IPI_one(cpu, vector);
330}
331
332static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
333{
334 void (*func) (void *info) = call_data->func;
335 void *info = call_data->info;
336 int wait = call_data->wait;
337
338 /*
339 * Notify initiating CPU that I've grabbed the data and am
340 * about to execute the function
341 */
342 mb();
343 atomic_inc(&call_data->started);
344 /*
345 * At this point the info structure may be out of scope unless wait==1
346 */
347 irq_enter();
348 (*func)(info);
349 irq_exit();
350
351 if (wait) {
352 mb(); /* commit everything before setting finished */
353 atomic_inc(&call_data->finished);
354 }
355
356 return IRQ_HANDLED;
357}
358
359int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
360 void *info, int wait)
361{
362 struct call_data_struct data;
363 int cpus;
364
365 /* Holding any lock stops cpus from going down. */
366 spin_lock(&call_lock);
367
368 cpu_clear(smp_processor_id(), mask);
369
370 cpus = cpus_weight(mask);
371 if (!cpus) {
372 spin_unlock(&call_lock);
373 return 0;
374 }
375
376 /* Can deadlock when called with interrupts disabled */
377 WARN_ON(irqs_disabled());
378
379 data.func = func;
380 data.info = info;
381 atomic_set(&data.started, 0);
382 data.wait = wait;
383 if (wait)
384 atomic_set(&data.finished, 0);
385
386 call_data = &data;
387 mb(); /* write everything before IPI */
388
389 /* Send a message to other CPUs and wait for them to respond */
390 xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
391
392 /* Make sure other vcpus get a chance to run.
393 XXX too severe? Maybe we should check the other CPU's states? */
394 HYPERVISOR_sched_op(SCHEDOP_yield, 0);
395
396 /* Wait for response */
397 while (atomic_read(&data.started) != cpus ||
398 (wait && atomic_read(&data.finished) != cpus))
399 cpu_relax();
400
401 spin_unlock(&call_lock);
402
403 return 0;
404}