--- /dev/null
+/*
+ * Intel SMP support routines.
+ *
+ * (c) 1995 Alan Cox, Building #3 <alan@redhat.com>
+ * (c) 1998-99, 2000 Ingo Molnar <mingo@redhat.com>
+ * (c) 2002,2003 Andi Kleen, SuSE Labs.
+ *
+ * This code is released under the GNU General Public License version 2 or
+ * later.
+ */
+
+#include <linux/init.h>
+
+#include <linux/mm.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/smp_lock.h>
+#include <linux/smp.h>
+#include <linux/kernel_stat.h>
+#include <linux/mc146818rtc.h>
+#include <linux/interrupt.h>
+
+#include <asm/mtrr.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/mach_apic.h>
+#include <asm/mmu_context.h>
+#include <asm/proto.h>
+#include <asm/apicdef.h>
+#include <asm/idle.h>
+#ifdef CONFIG_XEN
+#include <xen/evtchn.h>
+#endif
+
+#ifndef CONFIG_XEN
+/*
+ * Smarter SMP flushing macros.
+ * c/o Linus Torvalds.
+ *
+ * These mean you can really definitely utterly forget about
+ * writing to user space from interrupts. (Its not allowed anyway).
+ *
+ * Optimizations Manfred Spraul <manfred@colorfullife.com>
+ *
+ * More scalable flush, from Andi Kleen
+ *
+ * To avoid global state use 8 different call vectors.
+ * Each CPU uses a specific vector to trigger flushes on other
+ * CPUs. Depending on the received vector the target CPUs look into
+ * the right per cpu variable for the flush data.
+ *
+ * With more than 8 CPUs they are hashed to the 8 available
+ * vectors. The limited global vector space forces us to this right now.
+ * In future when interrupts are split into per CPU domains this could be
+ * fixed, at the cost of triggering multiple IPIs in some cases.
+ */
+
+union smp_flush_state {
+ struct {
+ cpumask_t flush_cpumask;
+ struct mm_struct *flush_mm;
+ unsigned long flush_va;
+#define FLUSH_ALL -1ULL
+ spinlock_t tlbstate_lock;
+ };
+ char pad[SMP_CACHE_BYTES];
+} ____cacheline_aligned;
+
+/* State is put into the per CPU data section, but padded
+ to a full cache line because other CPUs can access it and we don't
+ want false sharing in the per cpu data segment. */
+static DEFINE_PER_CPU(union smp_flush_state, flush_state);
+#endif
+
+/*
+ * We cannot call mmdrop() because we are in interrupt context,
+ * instead update mm->cpu_vm_mask.
+ */
+static inline void leave_mm(unsigned long cpu)
+{
+ if (read_pda(mmu_state) == TLBSTATE_OK)
+ BUG();
+ cpu_clear(cpu, read_pda(active_mm)->cpu_vm_mask);
+ load_cr3(swapper_pg_dir);
+}
+
+#ifndef CONFIG_XEN
+/*
+ *
+ * The flush IPI assumes that a thread switch happens in this order:
+ * [cpu0: the cpu that switches]
+ * 1) switch_mm() either 1a) or 1b)
+ * 1a) thread switch to a different mm
+ * 1a1) cpu_clear(cpu, old_mm->cpu_vm_mask);
+ * Stop ipi delivery for the old mm. This is not synchronized with
+ * the other cpus, but smp_invalidate_interrupt ignore flush ipis
+ * for the wrong mm, and in the worst case we perform a superfluous
+ * tlb flush.
+ * 1a2) set cpu mmu_state to TLBSTATE_OK
+ * Now the smp_invalidate_interrupt won't call leave_mm if cpu0
+ * was in lazy tlb mode.
+ * 1a3) update cpu active_mm
+ * Now cpu0 accepts tlb flushes for the new mm.
+ * 1a4) cpu_set(cpu, new_mm->cpu_vm_mask);
+ * Now the other cpus will send tlb flush ipis.
+ * 1a4) change cr3.
+ * 1b) thread switch without mm change
+ * cpu active_mm is correct, cpu0 already handles
+ * flush ipis.
+ * 1b1) set cpu mmu_state to TLBSTATE_OK
+ * 1b2) test_and_set the cpu bit in cpu_vm_mask.
+ * Atomically set the bit [other cpus will start sending flush ipis],
+ * and test the bit.
+ * 1b3) if the bit was 0: leave_mm was called, flush the tlb.
+ * 2) switch %%esp, ie current
+ *
+ * The interrupt must handle 2 special cases:
+ * - cr3 is changed before %%esp, ie. it cannot use current->{active_,}mm.
+ * - the cpu performs speculative tlb reads, i.e. even if the cpu only
+ * runs in kernel space, the cpu could load tlb entries for user space
+ * pages.
+ *
+ * The good news is that cpu mmu_state is local to each cpu, no
+ * write/read ordering problems.
+ */
+
+/*
+ * TLB flush IPI:
+ *
+ * 1) Flush the tlb entries if the cpu uses the mm that's being flushed.
+ * 2) Leave the mm if we are in the lazy tlb mode.
+ *
+ * Interrupts are disabled.
+ */
+
+asmlinkage void smp_invalidate_interrupt(struct pt_regs *regs)
+{
+ int cpu;
+ int sender;
+ union smp_flush_state *f;
+
+ cpu = smp_processor_id();
+ /*
+ * orig_rax contains the interrupt vector - 256.
+ * Use that to determine where the sender put the data.
+ */
+ sender = regs->orig_rax + 256 - INVALIDATE_TLB_VECTOR_START;
+ f = &per_cpu(flush_state, sender);
+
+ if (!cpu_isset(cpu, f->flush_cpumask))
+ goto out;
+ /*
+ * This was a BUG() but until someone can quote me the
+ * line from the intel manual that guarantees an IPI to
+ * multiple CPUs is retried _only_ on the erroring CPUs
+ * its staying as a return
+ *
+ * BUG();
+ */
+
+ if (f->flush_mm == read_pda(active_mm)) {
+ if (read_pda(mmu_state) == TLBSTATE_OK) {
+ if (f->flush_va == FLUSH_ALL)
+ local_flush_tlb();
+ else
+ __flush_tlb_one(f->flush_va);
+ } else
+ leave_mm(cpu);
+ }
+out:
+ ack_APIC_irq();
+ cpu_clear(cpu, f->flush_cpumask);
+}
+
+static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
+ unsigned long va)
+{
+ int sender;
+ union smp_flush_state *f;
+
+ /* Caller has disabled preemption */
+ sender = smp_processor_id() % NUM_INVALIDATE_TLB_VECTORS;
+ f = &per_cpu(flush_state, sender);
+
+ /* Could avoid this lock when
+ num_online_cpus() <= NUM_INVALIDATE_TLB_VECTORS, but it is
+ probably not worth checking this for a cache-hot lock. */
+ spin_lock(&f->tlbstate_lock);
+
+ f->flush_mm = mm;
+ f->flush_va = va;
+ cpus_or(f->flush_cpumask, cpumask, f->flush_cpumask);
+
+ /*
+ * We have to send the IPI only to
+ * CPUs affected.
+ */
+ send_IPI_mask(cpumask, INVALIDATE_TLB_VECTOR_START + sender);
+
+ while (!cpus_empty(f->flush_cpumask))
+ cpu_relax();
+
+ f->flush_mm = NULL;
+ f->flush_va = 0;
+ spin_unlock(&f->tlbstate_lock);
+}
+
+int __cpuinit init_smp_flush(void)
+{
+ int i;
+ for_each_cpu_mask(i, cpu_possible_map) {
+ spin_lock_init(&per_cpu(flush_state.tlbstate_lock, i));
+ }
+ return 0;
+}
+
+core_initcall(init_smp_flush);
+
+void flush_tlb_current_task(void)
+{
+ struct mm_struct *mm = current->mm;
+ cpumask_t cpu_mask;
+
+ preempt_disable();
+ cpu_mask = mm->cpu_vm_mask;
+ cpu_clear(smp_processor_id(), cpu_mask);
+
+ local_flush_tlb();
+ if (!cpus_empty(cpu_mask))
+ flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
+ preempt_enable();
+}
+
+void flush_tlb_mm (struct mm_struct * mm)
+{
+ cpumask_t cpu_mask;
+
+ preempt_disable();
+ cpu_mask = mm->cpu_vm_mask;
+ cpu_clear(smp_processor_id(), cpu_mask);
+
+ if (current->active_mm == mm) {
+ if (current->mm)
+ local_flush_tlb();
+ else
+ leave_mm(smp_processor_id());
+ }
+ if (!cpus_empty(cpu_mask))
+ flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
+
+ preempt_enable();
+}
+
+void flush_tlb_page(struct vm_area_struct * vma, unsigned long va)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ cpumask_t cpu_mask;
+
+ preempt_disable();
+ cpu_mask = mm->cpu_vm_mask;
+ cpu_clear(smp_processor_id(), cpu_mask);
+
+ if (current->active_mm == mm) {
+ if(current->mm)
+ __flush_tlb_one(va);
+ else
+ leave_mm(smp_processor_id());
+ }
+
+ if (!cpus_empty(cpu_mask))
+ flush_tlb_others(cpu_mask, mm, va);
+
+ preempt_enable();
+}
+
+static void do_flush_tlb_all(void* info)
+{
+ unsigned long cpu = smp_processor_id();
+
+ __flush_tlb_all();
+ if (read_pda(mmu_state) == TLBSTATE_LAZY)
+ leave_mm(cpu);
+}
+
+void flush_tlb_all(void)
+{
+ on_each_cpu(do_flush_tlb_all, NULL, 1, 1);
+}
+#else
+asmlinkage void smp_invalidate_interrupt (void)
+{ return; }
+void flush_tlb_current_task(void)
+{ xen_tlb_flush_mask(¤t->mm->cpu_vm_mask); }
+void flush_tlb_mm (struct mm_struct * mm)
+{ xen_tlb_flush_mask(&mm->cpu_vm_mask); }
+void flush_tlb_page(struct vm_area_struct * vma, unsigned long va)
+{ xen_invlpg_mask(&vma->vm_mm->cpu_vm_mask, va); }
+void flush_tlb_all(void)
+{ xen_tlb_flush_all(); }
+#endif /* Xen */
+
+/*
+ * this function sends a 'reschedule' IPI to another CPU.
+ * it goes straight through and wastes no time serializing
+ * anything. Worst case is that we lose a reschedule ...
+ */
+
+void smp_send_reschedule(int cpu)
+{
+ send_IPI_mask(cpumask_of_cpu(cpu), RESCHEDULE_VECTOR);
+}
+
+/*
+ * Structure and data for smp_call_function(). This is designed to minimise
+ * static memory requirements. It also looks cleaner.
+ */
+static DEFINE_SPINLOCK(call_lock);
+
+struct call_data_struct {
+ void (*func) (void *info);
+ void *info;
+ atomic_t started;
+ atomic_t finished;
+ int wait;
+};
+
+static struct call_data_struct * call_data;
+
+void lock_ipi_call_lock(void)
+{
+ spin_lock_irq(&call_lock);
+}
+
+void unlock_ipi_call_lock(void)
+{
+ spin_unlock_irq(&call_lock);
+}
+
+/*
+ * this function sends a 'generic call function' IPI to one other CPU
+ * in the system.
+ *
+ * cpu is a standard Linux logical CPU number.
+ */
+static void
+__smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+ int nonatomic, int wait)
+{
+ struct call_data_struct data;
+ int cpus = 1;
+
+ data.func = func;
+ data.info = info;
+ atomic_set(&data.started, 0);
+ data.wait = wait;
+ if (wait)
+ atomic_set(&data.finished, 0);
+
+ call_data = &data;
+ wmb();
+ /* Send a message to all other CPUs and wait for them to respond */
+ send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR);
+
+ /* Wait for response */
+ while (atomic_read(&data.started) != cpus)
+ cpu_relax();
+
+ if (!wait)
+ return;
+
+ while (atomic_read(&data.finished) != cpus)
+ cpu_relax();
+}
+
+/*
+ * smp_call_function_single - Run a function on another CPU
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: Currently unused.
+ * @wait: If true, wait until function has completed on other CPUs.
+ *
+ * Retrurns 0 on success, else a negative status code.
+ *
+ * Does not return until the remote CPU is nearly ready to execute <func>
+ * or is or has executed.
+ */
+
+int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
+ int nonatomic, int wait)
+{
+ /* prevent preemption and reschedule on another processor */
+ int me = get_cpu();
+ if (cpu == me) {
+ WARN_ON(1);
+ put_cpu();
+ return -EBUSY;
+ }
+ spin_lock_bh(&call_lock);
+ __smp_call_function_single(cpu, func, info, nonatomic, wait);
+ spin_unlock_bh(&call_lock);
+ put_cpu();
+ return 0;
+}
+
+/*
+ * this function sends a 'generic call function' IPI to all other CPUs
+ * in the system.
+ */
+static void __smp_call_function (void (*func) (void *info), void *info,
+ int nonatomic, int wait)
+{
+ struct call_data_struct data;
+ int cpus = num_online_cpus()-1;
+
+ if (!cpus)
+ return;
+
+ data.func = func;
+ data.info = info;
+ atomic_set(&data.started, 0);
+ data.wait = wait;
+ if (wait)
+ atomic_set(&data.finished, 0);
+
+ call_data = &data;
+ wmb();
+ /* Send a message to all other CPUs and wait for them to respond */
+ send_IPI_allbutself(CALL_FUNCTION_VECTOR);
+
+ /* Wait for response */
+ while (atomic_read(&data.started) != cpus)
+#ifndef CONFIG_XEN
+ cpu_relax();
+#else
+ barrier();
+#endif
+
+ if (!wait)
+ return;
+
+ while (atomic_read(&data.finished) != cpus)
+#ifndef CONFIG_XEN
+ cpu_relax();
+#else
+ barrier();
+#endif
+}
+
+/*
+ * smp_call_function - run a function on all other CPUs.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: currently unused.
+ * @wait: If true, wait (atomically) until function has completed on other
+ * CPUs.
+ *
+ * Returns 0 on success, else a negative status code. Does not return until
+ * remote CPUs are nearly ready to execute func or are or have executed.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ * Actually there are a few legal cases, like panic.
+ */
+int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
+ int wait)
+{
+ spin_lock(&call_lock);
+ __smp_call_function(func,info,nonatomic,wait);
+ spin_unlock(&call_lock);
+ return 0;
+}
+
+void smp_stop_cpu(void)
+{
+ unsigned long flags;
+ /*
+ * Remove this CPU:
+ */
+ cpu_clear(smp_processor_id(), cpu_online_map);
+ local_irq_save(flags);
+#ifndef CONFIG_XEN
+ disable_local_APIC();
+#endif
+ local_irq_restore(flags);
+}
+
+static void smp_really_stop_cpu(void *dummy)
+{
+ smp_stop_cpu();
+ for (;;)
+ halt();
+}
+
+void smp_send_stop(void)
+{
+ int nolock = 0;
+#ifndef CONFIG_XEN
+ if (reboot_force)
+ return;
+#endif
+ /* Don't deadlock on the call lock in panic */
+ if (!spin_trylock(&call_lock)) {
+ /* ignore locking because we have paniced anyways */
+ nolock = 1;
+ }
+ __smp_call_function(smp_really_stop_cpu, NULL, 0, 0);
+ if (!nolock)
+ spin_unlock(&call_lock);
+
+ local_irq_disable();
+#ifndef CONFIG_XEN
+ disable_local_APIC();
+#endif
+ local_irq_enable();
+}
+
+/*
+ * Reschedule call back. Nothing to do,
+ * all the work is done automatically when
+ * we return from the interrupt.
+ */
+#ifndef CONFIG_XEN
+asmlinkage void smp_reschedule_interrupt(void)
+#else
+asmlinkage irqreturn_t smp_reschedule_interrupt(void)
+#endif
+{
+#ifndef CONFIG_XEN
+ ack_APIC_irq();
+#else
+ return IRQ_HANDLED;
+#endif
+}
+
+#ifndef CONFIG_XEN
+asmlinkage void smp_call_function_interrupt(void)
+#else
+asmlinkage irqreturn_t smp_call_function_interrupt(void)
+#endif
+{
+ void (*func) (void *info) = call_data->func;
+ void *info = call_data->info;
+ int wait = call_data->wait;
+
+#ifndef CONFIG_XEN
+ ack_APIC_irq();
+#endif
+ /*
+ * Notify initiating CPU that I've grabbed the data and am
+ * about to execute the function
+ */
+ mb();
+ atomic_inc(&call_data->started);
+ /*
+ * At this point the info structure may be out of scope unless wait==1
+ */
+ exit_idle();
+ irq_enter();
+ (*func)(info);
+ irq_exit();
+ if (wait) {
+ mb();
+ atomic_inc(&call_data->finished);
+ }
+#ifdef CONFIG_XEN
+ return IRQ_HANDLED;
+#endif
+}
+
+int safe_smp_processor_id(void)
+{
+#ifdef CONFIG_XEN
+ return smp_processor_id();
+#else
+ int apicid, i;
+
+ if (disable_apic)
+ return 0;
+
+ apicid = hard_smp_processor_id();
+ if (x86_cpu_to_apicid[apicid] == apicid)
+ return apicid;
+
+ for (i = 0; i < NR_CPUS; ++i) {
+ if (x86_cpu_to_apicid[i] == apicid)
+ return i;
+ }
+
+ /* No entries in x86_cpu_to_apicid? Either no MPS|ACPI,
+ * or called too early. Either way, we must be CPU 0. */
+ if (x86_cpu_to_apicid[0] == BAD_APICID)
+ return 0;
+
+ return 0; /* Should not happen */
+#endif
+}
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