Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 415 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
new file mode 100644
index 00000000000..e3cdbf9a88b
--- /dev/null
+++ b/arch/x86_64/kernel/smp.c
@@ -0,0 +1,415 @@
+/*
+ *	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/irq.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>
+
+/*
+ *	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>
+ */
+
+static cpumask_t flush_cpumask;
+static struct mm_struct * flush_mm;
+static unsigned long flush_va;
+static DEFINE_SPINLOCK(tlbstate_lock);
+#define FLUSH_ALL	-1ULL
+
+/*
+ * 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();
+	clear_bit(cpu, &read_pda(active_mm)->cpu_vm_mask);
+	load_cr3(swapper_pg_dir);
+}
+
+/*
+ *
+ * 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) clear_bit(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) set_bit(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.
+ */
+
+asmlinkage void smp_invalidate_interrupt (void)
+{
+	unsigned long cpu;
+
+	cpu = get_cpu();
+
+	if (!cpu_isset(cpu, 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 (flush_mm == read_pda(active_mm)) {
+		if (read_pda(mmu_state) == TLBSTATE_OK) {
+			if (flush_va == FLUSH_ALL)
+				local_flush_tlb();
+			else
+				__flush_tlb_one(flush_va);
+		} else
+			leave_mm(cpu);
+	}
+	ack_APIC_irq();
+	cpu_clear(cpu, flush_cpumask);
+
+out:
+	put_cpu_no_resched();
+}
+
+static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
+						unsigned long va)
+{
+	cpumask_t tmp;
+	/*
+	 * A couple of (to be removed) sanity checks:
+	 *
+	 * - we do not send IPIs to not-yet booted CPUs.
+	 * - current CPU must not be in mask
+	 * - mask must exist :)
+	 */
+	BUG_ON(cpus_empty(cpumask));
+	cpus_and(tmp, cpumask, cpu_online_map);
+	BUG_ON(!cpus_equal(tmp, cpumask));
+	BUG_ON(cpu_isset(smp_processor_id(), cpumask));
+	if (!mm)
+		BUG();
+
+	/*
+	 * I'm not happy about this global shared spinlock in the
+	 * MM hot path, but we'll see how contended it is.
+	 * Temporarily this turns IRQs off, so that lockups are
+	 * detected by the NMI watchdog.
+	 */
+	spin_lock(&tlbstate_lock);
+	
+	flush_mm = mm;
+	flush_va = va;
+	cpus_or(flush_cpumask, cpumask, flush_cpumask);
+
+	/*
+	 * We have to send the IPI only to
+	 * CPUs affected.
+	 */
+	send_IPI_mask(cpumask, INVALIDATE_TLB_VECTOR);
+
+	while (!cpus_empty(flush_cpumask))
+		mb();	/* nothing. lockup detection does not belong here */;
+
+	flush_mm = NULL;
+	flush_va = 0;
+	spin_unlock(&tlbstate_lock);
+}
+	
+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);
+}
+
+void smp_kdb_stop(void)
+{
+	send_IPI_allbutself(KDB_VECTOR);
+}
+
+/*
+ * 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;
+
+/*
+ * 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)
+		cpu_relax();
+
+	if (!wait)
+		return;
+
+	while (atomic_read(&data.finished) != cpus)
+		cpu_relax();
+}
+
+/*
+ * 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)
+{
+	/*
+	 * Remove this CPU:
+	 */
+	cpu_clear(smp_processor_id(), cpu_online_map);
+	local_irq_disable();
+	disable_local_APIC();
+	local_irq_enable(); 
+}
+
+static void smp_really_stop_cpu(void *dummy)
+{
+	smp_stop_cpu(); 
+	for (;;) 
+		asm("hlt"); 
+} 
+
+void smp_send_stop(void)
+{
+	int nolock = 0;
+	if (reboot_force)
+		return;
+	/* 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();
+	disable_local_APIC();
+	local_irq_enable();
+}
+
+/*
+ * Reschedule call back. Nothing to do,
+ * all the work is done automatically when
+ * we return from the interrupt.
+ */
+asmlinkage void smp_reschedule_interrupt(void)
+{
+	ack_APIC_irq();
+}
+
+asmlinkage void smp_call_function_interrupt(void)
+{
+	void (*func) (void *info) = call_data->func;
+	void *info = call_data->info;
+	int wait = call_data->wait;
+
+	ack_APIC_irq();
+	/*
+	 * 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
+	 */
+	irq_enter();
+	(*func)(info);
+	irq_exit();
+	if (wait) {
+		mb();
+		atomic_inc(&call_data->finished);
+	}
+}