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.
8 * IPIs are handled through the Xen event mechanism.
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
15 #include <linux/sched.h>
16 #include <linux/err.h>
17 #include <linux/smp.h>
19 #include <asm/paravirt.h>
21 #include <asm/pgtable.h>
24 #include <xen/interface/xen.h>
25 #include <xen/interface/vcpu.h>
27 #include <asm/xen/interface.h>
28 #include <asm/xen/hypercall.h>
31 #include <xen/events.h>
36 cpumask_var_t xen_cpu_initialized_map
;
38 static DEFINE_PER_CPU(int, resched_irq
);
39 static DEFINE_PER_CPU(int, callfunc_irq
);
40 static DEFINE_PER_CPU(int, callfuncsingle_irq
);
41 static DEFINE_PER_CPU(int, debug_irq
) = -1;
43 static irqreturn_t
xen_call_function_interrupt(int irq
, void *dev_id
);
44 static irqreturn_t
xen_call_function_single_interrupt(int irq
, void *dev_id
);
47 * Reschedule call back. Nothing to do,
48 * all the work is done automatically when
49 * we return from the interrupt.
51 static irqreturn_t
xen_reschedule_interrupt(int irq
, void *dev_id
)
54 __get_cpu_var(irq_stat
).irq_resched_count
++;
56 add_pda(irq_resched_count
, 1);
62 static __cpuinit
void cpu_bringup(void)
64 int cpu
= smp_processor_id();
67 touch_softlockup_watchdog();
70 xen_enable_sysenter();
73 cpu
= smp_processor_id();
74 smp_store_cpu_info(cpu
);
75 cpu_data(cpu
).x86_max_cores
= 1;
76 set_cpu_sibling_map(cpu
);
78 xen_setup_cpu_clockevents();
80 cpu_set(cpu
, cpu_online_map
);
81 x86_write_percpu(cpu_state
, CPU_ONLINE
);
84 /* We can take interrupts now: we're officially "up". */
87 wmb(); /* make sure everything is out */
90 static __cpuinit
void cpu_bringup_and_idle(void)
96 static int xen_smp_intr_init(unsigned int cpu
)
99 const char *resched_name
, *callfunc_name
, *debug_name
;
101 resched_name
= kasprintf(GFP_KERNEL
, "resched%d", cpu
);
102 rc
= bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR
,
104 xen_reschedule_interrupt
,
105 IRQF_DISABLED
|IRQF_PERCPU
|IRQF_NOBALANCING
,
110 per_cpu(resched_irq
, cpu
) = rc
;
112 callfunc_name
= kasprintf(GFP_KERNEL
, "callfunc%d", cpu
);
113 rc
= bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR
,
115 xen_call_function_interrupt
,
116 IRQF_DISABLED
|IRQF_PERCPU
|IRQF_NOBALANCING
,
121 per_cpu(callfunc_irq
, cpu
) = rc
;
123 debug_name
= kasprintf(GFP_KERNEL
, "debug%d", cpu
);
124 rc
= bind_virq_to_irqhandler(VIRQ_DEBUG
, cpu
, xen_debug_interrupt
,
125 IRQF_DISABLED
| IRQF_PERCPU
| IRQF_NOBALANCING
,
129 per_cpu(debug_irq
, cpu
) = rc
;
131 callfunc_name
= kasprintf(GFP_KERNEL
, "callfuncsingle%d", cpu
);
132 rc
= bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR
,
134 xen_call_function_single_interrupt
,
135 IRQF_DISABLED
|IRQF_PERCPU
|IRQF_NOBALANCING
,
140 per_cpu(callfuncsingle_irq
, cpu
) = rc
;
145 if (per_cpu(resched_irq
, cpu
) >= 0)
146 unbind_from_irqhandler(per_cpu(resched_irq
, cpu
), NULL
);
147 if (per_cpu(callfunc_irq
, cpu
) >= 0)
148 unbind_from_irqhandler(per_cpu(callfunc_irq
, cpu
), NULL
);
149 if (per_cpu(debug_irq
, cpu
) >= 0)
150 unbind_from_irqhandler(per_cpu(debug_irq
, cpu
), NULL
);
151 if (per_cpu(callfuncsingle_irq
, cpu
) >= 0)
152 unbind_from_irqhandler(per_cpu(callfuncsingle_irq
, cpu
), NULL
);
157 static void __init
xen_fill_possible_map(void)
161 for (i
= 0; i
< nr_cpu_ids
; i
++) {
162 rc
= HYPERVISOR_vcpu_op(VCPUOP_is_up
, i
, NULL
);
165 cpu_set(i
, cpu_possible_map
);
170 static void __init
xen_smp_prepare_boot_cpu(void)
172 BUG_ON(smp_processor_id() != 0);
173 native_smp_prepare_boot_cpu();
175 /* We've switched to the "real" per-cpu gdt, so make sure the
176 old memory can be recycled */
177 make_lowmem_page_readwrite(&per_cpu_var(gdt_page
));
179 xen_setup_vcpu_info_placement();
182 static void __init
xen_smp_prepare_cpus(unsigned int max_cpus
)
186 xen_init_lock_cpu(0);
188 smp_store_cpu_info(0);
189 cpu_data(0).x86_max_cores
= 1;
190 set_cpu_sibling_map(0);
192 if (xen_smp_intr_init(0))
195 if (!alloc_cpumask_var(&xen_cpu_initialized_map
, GFP_KERNEL
))
196 panic("could not allocate xen_cpu_initialized_map\n");
198 cpumask_copy(xen_cpu_initialized_map
, cpumask_of(0));
200 /* Restrict the possible_map according to max_cpus. */
201 while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus
)) {
202 for (cpu
= nr_cpu_ids
- 1; !cpu_possible(cpu
); cpu
--)
204 cpu_clear(cpu
, cpu_possible_map
);
207 for_each_possible_cpu (cpu
) {
208 struct task_struct
*idle
;
213 idle
= fork_idle(cpu
);
215 panic("failed fork for CPU %d", cpu
);
217 cpu_set(cpu
, cpu_present_map
);
222 cpu_initialize_context(unsigned int cpu
, struct task_struct
*idle
)
224 struct vcpu_guest_context
*ctxt
;
225 struct desc_struct
*gdt
;
227 if (cpumask_test_and_set_cpu(cpu
, xen_cpu_initialized_map
))
230 ctxt
= kzalloc(sizeof(*ctxt
), GFP_KERNEL
);
234 gdt
= get_cpu_gdt_table(cpu
);
236 ctxt
->flags
= VGCF_IN_KERNEL
;
237 ctxt
->user_regs
.ds
= __USER_DS
;
238 ctxt
->user_regs
.es
= __USER_DS
;
239 ctxt
->user_regs
.ss
= __KERNEL_DS
;
241 ctxt
->user_regs
.fs
= __KERNEL_PERCPU
;
243 ctxt
->user_regs
.eip
= (unsigned long)cpu_bringup_and_idle
;
244 ctxt
->user_regs
.eflags
= 0x1000; /* IOPL_RING1 */
246 memset(&ctxt
->fpu_ctxt
, 0, sizeof(ctxt
->fpu_ctxt
));
248 xen_copy_trap_info(ctxt
->trap_ctxt
);
252 BUG_ON((unsigned long)gdt
& ~PAGE_MASK
);
253 make_lowmem_page_readonly(gdt
);
255 ctxt
->gdt_frames
[0] = virt_to_mfn(gdt
);
256 ctxt
->gdt_ents
= GDT_ENTRIES
;
258 ctxt
->user_regs
.cs
= __KERNEL_CS
;
259 ctxt
->user_regs
.esp
= idle
->thread
.sp0
- sizeof(struct pt_regs
);
261 ctxt
->kernel_ss
= __KERNEL_DS
;
262 ctxt
->kernel_sp
= idle
->thread
.sp0
;
265 ctxt
->event_callback_cs
= __KERNEL_CS
;
266 ctxt
->failsafe_callback_cs
= __KERNEL_CS
;
268 ctxt
->event_callback_eip
= (unsigned long)xen_hypervisor_callback
;
269 ctxt
->failsafe_callback_eip
= (unsigned long)xen_failsafe_callback
;
271 per_cpu(xen_cr3
, cpu
) = __pa(swapper_pg_dir
);
272 ctxt
->ctrlreg
[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir
));
274 if (HYPERVISOR_vcpu_op(VCPUOP_initialise
, cpu
, ctxt
))
281 static int __cpuinit
xen_cpu_up(unsigned int cpu
)
283 struct task_struct
*idle
= idle_task(cpu
);
287 /* Allocate node local memory for AP pdas */
290 rc
= get_local_pda(cpu
);
298 per_cpu(current_task
, cpu
) = idle
;
301 cpu_pda(cpu
)->pcurrent
= idle
;
302 clear_tsk_thread_flag(idle
, TIF_FORK
);
304 xen_setup_timer(cpu
);
305 xen_init_lock_cpu(cpu
);
307 per_cpu(cpu_state
, cpu
) = CPU_UP_PREPARE
;
309 /* make sure interrupts start blocked */
310 per_cpu(xen_vcpu
, cpu
)->evtchn_upcall_mask
= 1;
312 rc
= cpu_initialize_context(cpu
, idle
);
316 if (num_online_cpus() == 1)
317 alternatives_smp_switch(1);
319 rc
= xen_smp_intr_init(cpu
);
323 rc
= HYPERVISOR_vcpu_op(VCPUOP_up
, cpu
, NULL
);
326 while(per_cpu(cpu_state
, cpu
) != CPU_ONLINE
) {
327 HYPERVISOR_sched_op(SCHEDOP_yield
, 0);
334 static void xen_smp_cpus_done(unsigned int max_cpus
)
338 #ifdef CONFIG_HOTPLUG_CPU
339 static int xen_cpu_disable(void)
341 unsigned int cpu
= smp_processor_id();
345 cpu_disable_common();
347 load_cr3(swapper_pg_dir
);
351 static void xen_cpu_die(unsigned int cpu
)
353 while (HYPERVISOR_vcpu_op(VCPUOP_is_up
, cpu
, NULL
)) {
354 current
->state
= TASK_UNINTERRUPTIBLE
;
355 schedule_timeout(HZ
/10);
357 unbind_from_irqhandler(per_cpu(resched_irq
, cpu
), NULL
);
358 unbind_from_irqhandler(per_cpu(callfunc_irq
, cpu
), NULL
);
359 unbind_from_irqhandler(per_cpu(debug_irq
, cpu
), NULL
);
360 unbind_from_irqhandler(per_cpu(callfuncsingle_irq
, cpu
), NULL
);
361 xen_uninit_lock_cpu(cpu
);
362 xen_teardown_timer(cpu
);
364 if (num_online_cpus() == 1)
365 alternatives_smp_switch(0);
368 static void __cpuinit
xen_play_dead(void) /* used only with CPU_HOTPLUG */
371 HYPERVISOR_vcpu_op(VCPUOP_down
, smp_processor_id(), NULL
);
375 #else /* !CONFIG_HOTPLUG_CPU */
376 static int xen_cpu_disable(void)
381 static void xen_cpu_die(unsigned int cpu
)
386 static void xen_play_dead(void)
392 static void stop_self(void *v
)
394 int cpu
= smp_processor_id();
396 /* make sure we're not pinning something down */
397 load_cr3(swapper_pg_dir
);
398 /* should set up a minimal gdt */
400 HYPERVISOR_vcpu_op(VCPUOP_down
, cpu
, NULL
);
404 static void xen_smp_send_stop(void)
406 smp_call_function(stop_self
, NULL
, 0);
409 static void xen_smp_send_reschedule(int cpu
)
411 xen_send_IPI_one(cpu
, XEN_RESCHEDULE_VECTOR
);
414 static void xen_send_IPI_mask(const struct cpumask
*mask
,
415 enum ipi_vector vector
)
419 for_each_cpu_and(cpu
, mask
, cpu_online_mask
)
420 xen_send_IPI_one(cpu
, vector
);
423 static void xen_smp_send_call_function_ipi(const struct cpumask
*mask
)
427 xen_send_IPI_mask(mask
, XEN_CALL_FUNCTION_VECTOR
);
429 /* Make sure other vcpus get a chance to run if they need to. */
430 for_each_cpu(cpu
, mask
) {
431 if (xen_vcpu_stolen(cpu
)) {
432 HYPERVISOR_sched_op(SCHEDOP_yield
, 0);
438 static void xen_smp_send_call_function_single_ipi(int cpu
)
440 xen_send_IPI_mask(cpumask_of(cpu
),
441 XEN_CALL_FUNCTION_SINGLE_VECTOR
);
444 static irqreturn_t
xen_call_function_interrupt(int irq
, void *dev_id
)
447 generic_smp_call_function_interrupt();
449 __get_cpu_var(irq_stat
).irq_call_count
++;
451 add_pda(irq_call_count
, 1);
458 static irqreturn_t
xen_call_function_single_interrupt(int irq
, void *dev_id
)
461 generic_smp_call_function_single_interrupt();
463 __get_cpu_var(irq_stat
).irq_call_count
++;
465 add_pda(irq_call_count
, 1);
472 static const struct smp_ops xen_smp_ops __initdata
= {
473 .smp_prepare_boot_cpu
= xen_smp_prepare_boot_cpu
,
474 .smp_prepare_cpus
= xen_smp_prepare_cpus
,
475 .smp_cpus_done
= xen_smp_cpus_done
,
477 .cpu_up
= xen_cpu_up
,
478 .cpu_die
= xen_cpu_die
,
479 .cpu_disable
= xen_cpu_disable
,
480 .play_dead
= xen_play_dead
,
482 .smp_send_stop
= xen_smp_send_stop
,
483 .smp_send_reschedule
= xen_smp_send_reschedule
,
485 .send_call_func_ipi
= xen_smp_send_call_function_ipi
,
486 .send_call_func_single_ipi
= xen_smp_send_call_function_single_ipi
,
489 void __init
xen_smp_init(void)
491 smp_ops
= xen_smp_ops
;
492 xen_fill_possible_map();
493 xen_init_spinlocks();