Merge branches 'x86/urgent', 'x86/amd-iommu', 'x86/apic', 'x86/cleanups', 'x86/core...
[linux-2.6] / 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  * 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 cpumask_t xen_cpu_initialized_map;
39
40 static DEFINE_PER_CPU(int, resched_irq);
41 static DEFINE_PER_CPU(int, callfunc_irq);
42 static DEFINE_PER_CPU(int, callfuncsingle_irq);
43 static DEFINE_PER_CPU(int, 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 #ifdef CONFIG_X86_32
56         __get_cpu_var(irq_stat).irq_resched_count++;
57 #else
58         add_pda(irq_resched_count, 1);
59 #endif
60
61         return IRQ_HANDLED;
62 }
63
64 static __cpuinit void cpu_bringup_and_idle(void)
65 {
66         int cpu = smp_processor_id();
67
68         cpu_init();
69         preempt_disable();
70
71         xen_enable_sysenter();
72         xen_enable_syscall();
73
74         cpu = smp_processor_id();
75         smp_store_cpu_info(cpu);
76         cpu_data(cpu).x86_max_cores = 1;
77         set_cpu_sibling_map(cpu);
78
79         xen_setup_cpu_clockevents();
80
81         cpu_set(cpu, cpu_online_map);
82         x86_write_percpu(cpu_state, CPU_ONLINE);
83         wmb();
84
85         /* We can take interrupts now: we're officially "up". */
86         local_irq_enable();
87
88         wmb();                  /* make sure everything is out */
89         cpu_idle();
90 }
91
92 static int xen_smp_intr_init(unsigned int cpu)
93 {
94         int rc;
95         const char *resched_name, *callfunc_name, *debug_name;
96
97         resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
98         rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
99                                     cpu,
100                                     xen_reschedule_interrupt,
101                                     IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
102                                     resched_name,
103                                     NULL);
104         if (rc < 0)
105                 goto fail;
106         per_cpu(resched_irq, cpu) = rc;
107
108         callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
109         rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
110                                     cpu,
111                                     xen_call_function_interrupt,
112                                     IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
113                                     callfunc_name,
114                                     NULL);
115         if (rc < 0)
116                 goto fail;
117         per_cpu(callfunc_irq, cpu) = rc;
118
119         debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
120         rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
121                                      IRQF_DISABLED | IRQF_PERCPU | IRQF_NOBALANCING,
122                                      debug_name, NULL);
123         if (rc < 0)
124                 goto fail;
125         per_cpu(debug_irq, cpu) = rc;
126
127         callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
128         rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
129                                     cpu,
130                                     xen_call_function_single_interrupt,
131                                     IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
132                                     callfunc_name,
133                                     NULL);
134         if (rc < 0)
135                 goto fail;
136         per_cpu(callfuncsingle_irq, cpu) = rc;
137
138         return 0;
139
140  fail:
141         if (per_cpu(resched_irq, cpu) >= 0)
142                 unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL);
143         if (per_cpu(callfunc_irq, cpu) >= 0)
144                 unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL);
145         if (per_cpu(debug_irq, cpu) >= 0)
146                 unbind_from_irqhandler(per_cpu(debug_irq, cpu), NULL);
147         if (per_cpu(callfuncsingle_irq, cpu) >= 0)
148                 unbind_from_irqhandler(per_cpu(callfuncsingle_irq, cpu), NULL);
149
150         return rc;
151 }
152
153 static void __init xen_fill_possible_map(void)
154 {
155         int i, rc;
156
157         for (i = 0; i < NR_CPUS; i++) {
158                 rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
159                 if (rc >= 0) {
160                         num_processors++;
161                         cpu_set(i, cpu_possible_map);
162                 }
163         }
164 }
165
166 static void __init xen_smp_prepare_boot_cpu(void)
167 {
168         BUG_ON(smp_processor_id() != 0);
169         native_smp_prepare_boot_cpu();
170
171         /* We've switched to the "real" per-cpu gdt, so make sure the
172            old memory can be recycled */
173         make_lowmem_page_readwrite(&per_cpu_var(gdt_page));
174
175         xen_setup_vcpu_info_placement();
176 }
177
178 static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
179 {
180         unsigned cpu;
181
182         smp_store_cpu_info(0);
183         cpu_data(0).x86_max_cores = 1;
184         set_cpu_sibling_map(0);
185
186         if (xen_smp_intr_init(0))
187                 BUG();
188
189         xen_cpu_initialized_map = cpumask_of_cpu(0);
190
191         /* Restrict the possible_map according to max_cpus. */
192         while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
193                 for (cpu = NR_CPUS - 1; !cpu_possible(cpu); cpu--)
194                         continue;
195                 cpu_clear(cpu, cpu_possible_map);
196         }
197
198         for_each_possible_cpu (cpu) {
199                 struct task_struct *idle;
200
201                 if (cpu == 0)
202                         continue;
203
204                 idle = fork_idle(cpu);
205                 if (IS_ERR(idle))
206                         panic("failed fork for CPU %d", cpu);
207
208                 cpu_set(cpu, cpu_present_map);
209         }
210
211         //init_xenbus_allowed_cpumask();
212 }
213
214 static __cpuinit int
215 cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
216 {
217         struct vcpu_guest_context *ctxt;
218         struct desc_struct *gdt;
219
220         if (cpu_test_and_set(cpu, xen_cpu_initialized_map))
221                 return 0;
222
223         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
224         if (ctxt == NULL)
225                 return -ENOMEM;
226
227         gdt = get_cpu_gdt_table(cpu);
228
229         ctxt->flags = VGCF_IN_KERNEL;
230         ctxt->user_regs.ds = __USER_DS;
231         ctxt->user_regs.es = __USER_DS;
232         ctxt->user_regs.ss = __KERNEL_DS;
233 #ifdef CONFIG_X86_32
234         ctxt->user_regs.fs = __KERNEL_PERCPU;
235 #endif
236         ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
237         ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
238
239         memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
240
241         xen_copy_trap_info(ctxt->trap_ctxt);
242
243         ctxt->ldt_ents = 0;
244
245         BUG_ON((unsigned long)gdt & ~PAGE_MASK);
246         make_lowmem_page_readonly(gdt);
247
248         ctxt->gdt_frames[0] = virt_to_mfn(gdt);
249         ctxt->gdt_ents      = GDT_ENTRIES;
250
251         ctxt->user_regs.cs = __KERNEL_CS;
252         ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
253
254         ctxt->kernel_ss = __KERNEL_DS;
255         ctxt->kernel_sp = idle->thread.sp0;
256
257 #ifdef CONFIG_X86_32
258         ctxt->event_callback_cs     = __KERNEL_CS;
259         ctxt->failsafe_callback_cs  = __KERNEL_CS;
260 #endif
261         ctxt->event_callback_eip    = (unsigned long)xen_hypervisor_callback;
262         ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
263
264         per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
265         ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
266
267         if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
268                 BUG();
269
270         kfree(ctxt);
271         return 0;
272 }
273
274 static int __cpuinit xen_cpu_up(unsigned int cpu)
275 {
276         struct task_struct *idle = idle_task(cpu);
277         int rc;
278
279 #if 0
280         rc = cpu_up_check(cpu);
281         if (rc)
282                 return rc;
283 #endif
284
285 #ifdef CONFIG_X86_64
286         /* Allocate node local memory for AP pdas */
287         WARN_ON(cpu == 0);
288         if (cpu > 0) {
289                 rc = get_local_pda(cpu);
290                 if (rc)
291                         return rc;
292         }
293 #endif
294
295 #ifdef CONFIG_X86_32
296         init_gdt(cpu);
297         per_cpu(current_task, cpu) = idle;
298         irq_ctx_init(cpu);
299 #else
300         cpu_pda(cpu)->pcurrent = idle;
301         clear_tsk_thread_flag(idle, TIF_FORK);
302 #endif
303         xen_setup_timer(cpu);
304
305         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
306
307         /* make sure interrupts start blocked */
308         per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
309
310         rc = cpu_initialize_context(cpu, idle);
311         if (rc)
312                 return rc;
313
314         if (num_online_cpus() == 1)
315                 alternatives_smp_switch(1);
316
317         rc = xen_smp_intr_init(cpu);
318         if (rc)
319                 return rc;
320
321         rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
322         BUG_ON(rc);
323
324         while(per_cpu(cpu_state, cpu) != CPU_ONLINE) {
325                 HYPERVISOR_sched_op(SCHEDOP_yield, 0);
326                 barrier();
327         }
328
329         return 0;
330 }
331
332 static void xen_smp_cpus_done(unsigned int max_cpus)
333 {
334 }
335
336 static void stop_self(void *v)
337 {
338         int cpu = smp_processor_id();
339
340         /* make sure we're not pinning something down */
341         load_cr3(swapper_pg_dir);
342         /* should set up a minimal gdt */
343
344         HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
345         BUG();
346 }
347
348 static void xen_smp_send_stop(void)
349 {
350         smp_call_function(stop_self, NULL, 0);
351 }
352
353 static void xen_smp_send_reschedule(int cpu)
354 {
355         xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
356 }
357
358 static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector)
359 {
360         unsigned cpu;
361
362         cpus_and(mask, mask, cpu_online_map);
363
364         for_each_cpu_mask(cpu, mask)
365                 xen_send_IPI_one(cpu, vector);
366 }
367
368 static void xen_smp_send_call_function_ipi(cpumask_t mask)
369 {
370         int cpu;
371
372         xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
373
374         /* Make sure other vcpus get a chance to run if they need to. */
375         for_each_cpu_mask(cpu, mask) {
376                 if (xen_vcpu_stolen(cpu)) {
377                         HYPERVISOR_sched_op(SCHEDOP_yield, 0);
378                         break;
379                 }
380         }
381 }
382
383 static void xen_smp_send_call_function_single_ipi(int cpu)
384 {
385         xen_send_IPI_mask(cpumask_of_cpu(cpu), XEN_CALL_FUNCTION_SINGLE_VECTOR);
386 }
387
388 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
389 {
390         irq_enter();
391         generic_smp_call_function_interrupt();
392 #ifdef CONFIG_X86_32
393         __get_cpu_var(irq_stat).irq_call_count++;
394 #else
395         add_pda(irq_call_count, 1);
396 #endif
397         irq_exit();
398
399         return IRQ_HANDLED;
400 }
401
402 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
403 {
404         irq_enter();
405         generic_smp_call_function_single_interrupt();
406 #ifdef CONFIG_X86_32
407         __get_cpu_var(irq_stat).irq_call_count++;
408 #else
409         add_pda(irq_call_count, 1);
410 #endif
411         irq_exit();
412
413         return IRQ_HANDLED;
414 }
415
416 static const struct smp_ops xen_smp_ops __initdata = {
417         .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
418         .smp_prepare_cpus = xen_smp_prepare_cpus,
419         .cpu_up = xen_cpu_up,
420         .smp_cpus_done = xen_smp_cpus_done,
421
422         .smp_send_stop = xen_smp_send_stop,
423         .smp_send_reschedule = xen_smp_send_reschedule,
424
425         .send_call_func_ipi = xen_smp_send_call_function_ipi,
426         .send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
427 };
428
429 void __init xen_smp_init(void)
430 {
431         smp_ops = xen_smp_ops;
432         xen_fill_possible_map();
433 }