Showing error 879

User: Jiri Slaby
Error type: Resource Leak
Error type description: The code omits to put the resource to the system for reuse
File location: arch/x86/xen/smp.c
Line in file: 68
Project: Linux Kernel
Project version: 2.6.28
Tools: Stanse (1.2)
Entered: 2011-11-07 22:40:13 UTC

Source: 

  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/smp.h>
 18
 19#include <asm/paravirt.h>
 20#include <asm/desc.h>
 21#include <asm/pgtable.h>
 22#include <asm/cpu.h>
 23
 24#include <xen/interface/xen.h>
 25#include <xen/interface/vcpu.h>
 26
 27#include <asm/xen/interface.h>
 28#include <asm/xen/hypercall.h>
 29
 30#include <xen/page.h>
 31#include <xen/events.h>
 32
 33#include "xen-ops.h"
 34#include "mmu.h"
 35
 36cpumask_t xen_cpu_initialized_map;
 37
 38static DEFINE_PER_CPU(int, resched_irq);
 39static DEFINE_PER_CPU(int, callfunc_irq);
 40static DEFINE_PER_CPU(int, callfuncsingle_irq);
 41static DEFINE_PER_CPU(int, debug_irq) = -1;
 42
 43static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
 44static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
 45
 46/*
 47 * Reschedule call back. Nothing to do,
 48 * all the work is done automatically when
 49 * we return from the interrupt.
 50 */
 51static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
 52{
 53#ifdef CONFIG_X86_32
 54        __get_cpu_var(irq_stat).irq_resched_count++;
 55#else
 56        add_pda(irq_resched_count, 1);
 57#endif
 58
 59        return IRQ_HANDLED;
 60}
 61
 62static __cpuinit void cpu_bringup(void)
 63{
 64        int cpu = smp_processor_id();
 65
 66        cpu_init();
 67        touch_softlockup_watchdog();
 68        preempt_disable();
 69
 70        xen_enable_sysenter();
 71        xen_enable_syscall();
 72
 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);
 77
 78        xen_setup_cpu_clockevents();
 79
 80        cpu_set(cpu, cpu_online_map);
 81        x86_write_percpu(cpu_state, CPU_ONLINE);
 82        wmb();
 83
 84        /* We can take interrupts now: we're officially "up". */
 85        local_irq_enable();
 86
 87        wmb();                        /* make sure everything is out */
 88}
 89
 90static __cpuinit void cpu_bringup_and_idle(void)
 91{
 92        cpu_bringup();
 93        cpu_idle();
 94}
 95
 96static int xen_smp_intr_init(unsigned int cpu)
 97{
 98        int rc;
 99        const char *resched_name, *callfunc_name, *debug_name;
100
101        resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
102        rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
103                                    cpu,
104                                    xen_reschedule_interrupt,
105                                    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
106                                    resched_name,
107                                    NULL);
108        if (rc < 0)
109                goto fail;
110        per_cpu(resched_irq, cpu) = rc;
111
112        callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
113        rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
114                                    cpu,
115                                    xen_call_function_interrupt,
116                                    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
117                                    callfunc_name,
118                                    NULL);
119        if (rc < 0)
120                goto fail;
121        per_cpu(callfunc_irq, cpu) = rc;
122
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,
126                                     debug_name, NULL);
127        if (rc < 0)
128                goto fail;
129        per_cpu(debug_irq, cpu) = rc;
130
131        callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
132        rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
133                                    cpu,
134                                    xen_call_function_single_interrupt,
135                                    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
136                                    callfunc_name,
137                                    NULL);
138        if (rc < 0)
139                goto fail;
140        per_cpu(callfuncsingle_irq, cpu) = rc;
141
142        return 0;
143
144 fail:
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);
153
154        return rc;
155}
156
157static void __init xen_fill_possible_map(void)
158{
159        int i, rc;
160
161        for (i = 0; i < NR_CPUS; i++) {
162                rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
163                if (rc >= 0) {
164                        num_processors++;
165                        cpu_set(i, cpu_possible_map);
166                }
167        }
168}
169
170static void __init xen_smp_prepare_boot_cpu(void)
171{
172        BUG_ON(smp_processor_id() != 0);
173        native_smp_prepare_boot_cpu();
174
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));
178
179        xen_setup_vcpu_info_placement();
180}
181
182static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
183{
184        unsigned cpu;
185
186        xen_init_lock_cpu(0);
187
188        smp_store_cpu_info(0);
189        cpu_data(0).x86_max_cores = 1;
190        set_cpu_sibling_map(0);
191
192        if (xen_smp_intr_init(0))
193                BUG();
194
195        xen_cpu_initialized_map = cpumask_of_cpu(0);
196
197        /* Restrict the possible_map according to max_cpus. */
198        while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
199                for (cpu = NR_CPUS - 1; !cpu_possible(cpu); cpu--)
200                        continue;
201                cpu_clear(cpu, cpu_possible_map);
202        }
203
204        for_each_possible_cpu (cpu) {
205                struct task_struct *idle;
206
207                if (cpu == 0)
208                        continue;
209
210                idle = fork_idle(cpu);
211                if (IS_ERR(idle))
212                        panic("failed fork for CPU %d", cpu);
213
214                cpu_set(cpu, cpu_present_map);
215        }
216}
217
218static __cpuinit int
219cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
220{
221        struct vcpu_guest_context *ctxt;
222        struct desc_struct *gdt;
223
224        if (cpu_test_and_set(cpu, xen_cpu_initialized_map))
225                return 0;
226
227        ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
228        if (ctxt == NULL)
229                return -ENOMEM;
230
231        gdt = get_cpu_gdt_table(cpu);
232
233        ctxt->flags = VGCF_IN_KERNEL;
234        ctxt->user_regs.ds = __USER_DS;
235        ctxt->user_regs.es = __USER_DS;
236        ctxt->user_regs.ss = __KERNEL_DS;
237#ifdef CONFIG_X86_32
238        ctxt->user_regs.fs = __KERNEL_PERCPU;
239#endif
240        ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
241        ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
242
243        memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
244
245        xen_copy_trap_info(ctxt->trap_ctxt);
246
247        ctxt->ldt_ents = 0;
248
249        BUG_ON((unsigned long)gdt & ~PAGE_MASK);
250        make_lowmem_page_readonly(gdt);
251
252        ctxt->gdt_frames[0] = virt_to_mfn(gdt);
253        ctxt->gdt_ents      = GDT_ENTRIES;
254
255        ctxt->user_regs.cs = __KERNEL_CS;
256        ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
257
258        ctxt->kernel_ss = __KERNEL_DS;
259        ctxt->kernel_sp = idle->thread.sp0;
260
261#ifdef CONFIG_X86_32
262        ctxt->event_callback_cs     = __KERNEL_CS;
263        ctxt->failsafe_callback_cs  = __KERNEL_CS;
264#endif
265        ctxt->event_callback_eip    = (unsigned long)xen_hypervisor_callback;
266        ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
267
268        per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
269        ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
270
271        if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
272                BUG();
273
274        kfree(ctxt);
275        return 0;
276}
277
278static int __cpuinit xen_cpu_up(unsigned int cpu)
279{
280        struct task_struct *idle = idle_task(cpu);
281        int rc;
282
283#ifdef CONFIG_X86_64
284        /* Allocate node local memory for AP pdas */
285        WARN_ON(cpu == 0);
286        if (cpu > 0) {
287                rc = get_local_pda(cpu);
288                if (rc)
289                        return rc;
290        }
291#endif
292
293#ifdef CONFIG_X86_32
294        init_gdt(cpu);
295        per_cpu(current_task, cpu) = idle;
296        irq_ctx_init(cpu);
297#else
298        cpu_pda(cpu)->pcurrent = idle;
299        clear_tsk_thread_flag(idle, TIF_FORK);
300#endif
301        xen_setup_timer(cpu);
302        xen_init_lock_cpu(cpu);
303
304        per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
305
306        /* make sure interrupts start blocked */
307        per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
308
309        rc = cpu_initialize_context(cpu, idle);
310        if (rc)
311                return rc;
312
313        if (num_online_cpus() == 1)
314                alternatives_smp_switch(1);
315
316        rc = xen_smp_intr_init(cpu);
317        if (rc)
318                return rc;
319
320        rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
321        BUG_ON(rc);
322
323        while(per_cpu(cpu_state, cpu) != CPU_ONLINE) {
324                HYPERVISOR_sched_op(SCHEDOP_yield, 0);
325                barrier();
326        }
327
328        return 0;
329}
330
331static void xen_smp_cpus_done(unsigned int max_cpus)
332{
333}
334
335#ifdef CONFIG_HOTPLUG_CPU
336static int xen_cpu_disable(void)
337{
338        unsigned int cpu = smp_processor_id();
339        if (cpu == 0)
340                return -EBUSY;
341
342        cpu_disable_common();
343
344        load_cr3(swapper_pg_dir);
345        return 0;
346}
347
348static void xen_cpu_die(unsigned int cpu)
349{
350        while (HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL)) {
351                current->state = TASK_UNINTERRUPTIBLE;
352                schedule_timeout(HZ/10);
353        }
354        unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL);
355        unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL);
356        unbind_from_irqhandler(per_cpu(debug_irq, cpu), NULL);
357        unbind_from_irqhandler(per_cpu(callfuncsingle_irq, cpu), NULL);
358        xen_uninit_lock_cpu(cpu);
359        xen_teardown_timer(cpu);
360
361        if (num_online_cpus() == 1)
362                alternatives_smp_switch(0);
363}
364
365static void __cpuinit xen_play_dead(void) /* used only with CPU_HOTPLUG */
366{
367        play_dead_common();
368        HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
369        cpu_bringup();
370}
371
372#else /* !CONFIG_HOTPLUG_CPU */
373static int xen_cpu_disable(void)
374{
375        return -ENOSYS;
376}
377
378static void xen_cpu_die(unsigned int cpu)
379{
380        BUG();
381}
382
383static void xen_play_dead(void)
384{
385        BUG();
386}
387
388#endif
389static void stop_self(void *v)
390{
391        int cpu = smp_processor_id();
392
393        /* make sure we're not pinning something down */
394        load_cr3(swapper_pg_dir);
395        /* should set up a minimal gdt */
396
397        HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
398        BUG();
399}
400
401static void xen_smp_send_stop(void)
402{
403        smp_call_function(stop_self, NULL, 0);
404}
405
406static void xen_smp_send_reschedule(int cpu)
407{
408        xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
409}
410
411static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector)
412{
413        unsigned cpu;
414
415        cpus_and(mask, mask, cpu_online_map);
416
417        for_each_cpu_mask_nr(cpu, mask)
418                xen_send_IPI_one(cpu, vector);
419}
420
421static void xen_smp_send_call_function_ipi(cpumask_t mask)
422{
423        int cpu;
424
425        xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
426
427        /* Make sure other vcpus get a chance to run if they need to. */
428        for_each_cpu_mask_nr(cpu, mask) {
429                if (xen_vcpu_stolen(cpu)) {
430                        HYPERVISOR_sched_op(SCHEDOP_yield, 0);
431                        break;
432                }
433        }
434}
435
436static void xen_smp_send_call_function_single_ipi(int cpu)
437{
438        xen_send_IPI_mask(cpumask_of_cpu(cpu), XEN_CALL_FUNCTION_SINGLE_VECTOR);
439}
440
441static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
442{
443        irq_enter();
444        generic_smp_call_function_interrupt();
445#ifdef CONFIG_X86_32
446        __get_cpu_var(irq_stat).irq_call_count++;
447#else
448        add_pda(irq_call_count, 1);
449#endif
450        irq_exit();
451
452        return IRQ_HANDLED;
453}
454
455static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
456{
457        irq_enter();
458        generic_smp_call_function_single_interrupt();
459#ifdef CONFIG_X86_32
460        __get_cpu_var(irq_stat).irq_call_count++;
461#else
462        add_pda(irq_call_count, 1);
463#endif
464        irq_exit();
465
466        return IRQ_HANDLED;
467}
468
469static const struct smp_ops xen_smp_ops __initdata = {
470        .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
471        .smp_prepare_cpus = xen_smp_prepare_cpus,
472        .smp_cpus_done = xen_smp_cpus_done,
473
474        .cpu_up = xen_cpu_up,
475        .cpu_die = xen_cpu_die,
476        .cpu_disable = xen_cpu_disable,
477        .play_dead = xen_play_dead,
478
479        .smp_send_stop = xen_smp_send_stop,
480        .smp_send_reschedule = xen_smp_send_reschedule,
481
482        .send_call_func_ipi = xen_smp_send_call_function_ipi,
483        .send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
484};
485
486void __init xen_smp_init(void)
487{
488        smp_ops = xen_smp_ops;
489        xen_fill_possible_map();
490        xen_init_spinlocks();
491}
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