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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/smp.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
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!
Diffstat (limited to 'arch/i386/kernel/smp.c')
-rw-r--r--arch/i386/kernel/smp.c612
1 files changed, 612 insertions, 0 deletions
diff --git a/arch/i386/kernel/smp.c b/arch/i386/kernel/smp.c
new file mode 100644
index 00000000000..6223c33ac91
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+++ b/arch/i386/kernel/smp.c
@@ -0,0 +1,612 @@
+/*
+ * Intel SMP support routines.
+ *
+ * (c) 1995 Alan Cox, Building #3 <alan@redhat.com>
+ * (c) 1998-99, 2000 Ingo Molnar <mingo@redhat.com>
+ *
+ * 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/kernel_stat.h>
+#include <linux/mc146818rtc.h>
+#include <linux/cache.h>
+#include <linux/interrupt.h>
+
+#include <asm/mtrr.h>
+#include <asm/tlbflush.h>
+#include <mach_apic.h>
+
+/*
+ * Some notes on x86 processor bugs affecting SMP operation:
+ *
+ * Pentium, Pentium Pro, II, III (and all CPUs) have bugs.
+ * The Linux implications for SMP are handled as follows:
+ *
+ * Pentium III / [Xeon]
+ * None of the E1AP-E3AP errata are visible to the user.
+ *
+ * E1AP. see PII A1AP
+ * E2AP. see PII A2AP
+ * E3AP. see PII A3AP
+ *
+ * Pentium II / [Xeon]
+ * None of the A1AP-A3AP errata are visible to the user.
+ *
+ * A1AP. see PPro 1AP
+ * A2AP. see PPro 2AP
+ * A3AP. see PPro 7AP
+ *
+ * Pentium Pro
+ * None of 1AP-9AP errata are visible to the normal user,
+ * except occasional delivery of 'spurious interrupt' as trap #15.
+ * This is very rare and a non-problem.
+ *
+ * 1AP. Linux maps APIC as non-cacheable
+ * 2AP. worked around in hardware
+ * 3AP. fixed in C0 and above steppings microcode update.
+ * Linux does not use excessive STARTUP_IPIs.
+ * 4AP. worked around in hardware
+ * 5AP. symmetric IO mode (normal Linux operation) not affected.
+ * 'noapic' mode has vector 0xf filled out properly.
+ * 6AP. 'noapic' mode might be affected - fixed in later steppings
+ * 7AP. We do not assume writes to the LVT deassering IRQs
+ * 8AP. We do not enable low power mode (deep sleep) during MP bootup
+ * 9AP. We do not use mixed mode
+ *
+ * Pentium
+ * There is a marginal case where REP MOVS on 100MHz SMP
+ * machines with B stepping processors can fail. XXX should provide
+ * an L1cache=Writethrough or L1cache=off option.
+ *
+ * B stepping CPUs may hang. There are hardware work arounds
+ * for this. We warn about it in case your board doesn't have the work
+ * arounds. Basically thats so I can tell anyone with a B stepping
+ * CPU and SMP problems "tough".
+ *
+ * Specific items [From Pentium Processor Specification Update]
+ *
+ * 1AP. Linux doesn't use remote read
+ * 2AP. Linux doesn't trust APIC errors
+ * 3AP. We work around this
+ * 4AP. Linux never generated 3 interrupts of the same priority
+ * to cause a lost local interrupt.
+ * 5AP. Remote read is never used
+ * 6AP. not affected - worked around in hardware
+ * 7AP. not affected - worked around in hardware
+ * 8AP. worked around in hardware - we get explicit CS errors if not
+ * 9AP. only 'noapic' mode affected. Might generate spurious
+ * interrupts, we log only the first one and count the
+ * rest silently.
+ * 10AP. not affected - worked around in hardware
+ * 11AP. Linux reads the APIC between writes to avoid this, as per
+ * the documentation. Make sure you preserve this as it affects
+ * the C stepping chips too.
+ * 12AP. not affected - worked around in hardware
+ * 13AP. not affected - worked around in hardware
+ * 14AP. we always deassert INIT during bootup
+ * 15AP. not affected - worked around in hardware
+ * 16AP. not affected - worked around in hardware
+ * 17AP. not affected - worked around in hardware
+ * 18AP. not affected - worked around in hardware
+ * 19AP. not affected - worked around in BIOS
+ *
+ * If this sounds worrying believe me these bugs are either ___RARE___,
+ * or are signal timing bugs worked around in hardware and there's
+ * about nothing of note with C stepping upwards.
+ */
+
+DEFINE_PER_CPU(struct tlb_state, cpu_tlbstate) ____cacheline_aligned = { &init_mm, 0, };
+
+/*
+ * the following functions deal with sending IPIs between CPUs.
+ *
+ * We use 'broadcast', CPU->CPU IPIs and self-IPIs too.
+ */
+
+static inline int __prepare_ICR (unsigned int shortcut, int vector)
+{
+ return APIC_DM_FIXED | shortcut | vector | APIC_DEST_LOGICAL;
+}
+
+static inline int __prepare_ICR2 (unsigned int mask)
+{
+ return SET_APIC_DEST_FIELD(mask);
+}
+
+void __send_IPI_shortcut(unsigned int shortcut, int vector)
+{
+ /*
+ * Subtle. In the case of the 'never do double writes' workaround
+ * we have to lock out interrupts to be safe. As we don't care
+ * of the value read we use an atomic rmw access to avoid costly
+ * cli/sti. Otherwise we use an even cheaper single atomic write
+ * to the APIC.
+ */
+ unsigned int cfg;
+
+ /*
+ * Wait for idle.
+ */
+ apic_wait_icr_idle();
+
+ /*
+ * No need to touch the target chip field
+ */
+ cfg = __prepare_ICR(shortcut, vector);
+
+ /*
+ * Send the IPI. The write to APIC_ICR fires this off.
+ */
+ apic_write_around(APIC_ICR, cfg);
+}
+
+void fastcall send_IPI_self(int vector)
+{
+ __send_IPI_shortcut(APIC_DEST_SELF, vector);
+}
+
+/*
+ * This is only used on smaller machines.
+ */
+void send_IPI_mask_bitmask(cpumask_t cpumask, int vector)
+{
+ unsigned long mask = cpus_addr(cpumask)[0];
+ unsigned long cfg;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ /*
+ * Wait for idle.
+ */
+ apic_wait_icr_idle();
+
+ /*
+ * prepare target chip field
+ */
+ cfg = __prepare_ICR2(mask);
+ apic_write_around(APIC_ICR2, cfg);
+
+ /*
+ * program the ICR
+ */
+ cfg = __prepare_ICR(0, vector);
+
+ /*
+ * Send the IPI. The write to APIC_ICR fires this off.
+ */
+ apic_write_around(APIC_ICR, cfg);
+
+ local_irq_restore(flags);
+}
+
+void send_IPI_mask_sequence(cpumask_t mask, int vector)
+{
+ unsigned long cfg, flags;
+ unsigned int query_cpu;
+
+ /*
+ * Hack. The clustered APIC addressing mode doesn't allow us to send
+ * to an arbitrary mask, so I do a unicasts to each CPU instead. This
+ * should be modified to do 1 message per cluster ID - mbligh
+ */
+
+ local_irq_save(flags);
+
+ for (query_cpu = 0; query_cpu < NR_CPUS; ++query_cpu) {
+ if (cpu_isset(query_cpu, mask)) {
+
+ /*
+ * Wait for idle.
+ */
+ apic_wait_icr_idle();
+
+ /*
+ * prepare target chip field
+ */
+ cfg = __prepare_ICR2(cpu_to_logical_apicid(query_cpu));
+ apic_write_around(APIC_ICR2, cfg);
+
+ /*
+ * program the ICR
+ */
+ cfg = __prepare_ICR(0, vector);
+
+ /*
+ * Send the IPI. The write to APIC_ICR fires this off.
+ */
+ apic_write_around(APIC_ICR, cfg);
+ }
+ }
+ local_irq_restore(flags);
+}
+
+#include <mach_ipi.h> /* must come after the send_IPI functions above for inlining */
+
+/*
+ * 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 0xffffffff
+
+/*
+ * We cannot call mmdrop() because we are in interrupt context,
+ * instead update mm->cpu_vm_mask.
+ *
+ * We need to reload %cr3 since the page tables may be going
+ * away from under us..
+ */
+static inline void leave_mm (unsigned long cpu)
+{
+ if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
+ BUG();
+ cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).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) 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 superflous
+ * tlb flush.
+ * 1a2) set cpu_tlbstate to TLBSTATE_OK
+ * Now the smp_invalidate_interrupt won't call leave_mm if cpu0
+ * was in lazy tlb mode.
+ * 1a3) update cpu_tlbstate[].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_tlbstate[].active_mm is correct, cpu0 already handles
+ * flush ipis.
+ * 1b1) set cpu_tlbstate 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_tlbstate 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.
+ */
+
+fastcall void smp_invalidate_interrupt(struct pt_regs *regs)
+{
+ 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 == per_cpu(cpu_tlbstate, cpu).active_mm) {
+ if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK) {
+ if (flush_va == FLUSH_ALL)
+ local_flush_tlb();
+ else
+ __flush_tlb_one(flush_va);
+ } else
+ leave_mm(cpu);
+ }
+ ack_APIC_irq();
+ smp_mb__before_clear_bit();
+ cpu_clear(cpu, flush_cpumask);
+ smp_mb__after_clear_bit();
+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(cpumask, tmp));
+ BUG_ON(cpu_isset(smp_processor_id(), cpumask));
+ BUG_ON(!mm);
+
+ /*
+ * 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;
+#if NR_CPUS <= BITS_PER_LONG
+ atomic_set_mask(cpumask, &flush_cpumask);
+#else
+ {
+ int k;
+ unsigned long *flush_mask = (unsigned long *)&flush_cpumask;
+ unsigned long *cpu_mask = (unsigned long *)&cpumask;
+ for (k = 0; k < BITS_TO_LONGS(NR_CPUS); ++k)
+ atomic_set_mask(cpu_mask[k], &flush_mask[k]);
+ }
+#endif
+ /*
+ * We have to send the IPI only to
+ * CPUs affected.
+ */
+ send_IPI_mask(cpumask, INVALIDATE_TLB_VECTOR);
+
+ while (!cpus_empty(flush_cpumask))
+ /* nothing. lockup detection does not belong here */
+ mb();
+
+ 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 (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_LAZY)
+ leave_mm(cpu);
+}
+
+void flush_tlb_all(void)
+{
+ on_each_cpu(do_flush_tlb_all, NULL, 1, 1);
+}
+
+/*
+ * 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.
+ */
+
+int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
+ int wait)
+/*
+ * [SUMMARY] 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.
+ */
+{
+ struct call_data_struct data;
+ int cpus = num_online_cpus()-1;
+
+ if (!cpus)
+ return 0;
+
+ /* Can deadlock when called with interrupts disabled */
+ WARN_ON(irqs_disabled());
+
+ data.func = func;
+ data.info = info;
+ atomic_set(&data.started, 0);
+ data.wait = wait;
+ if (wait)
+ atomic_set(&data.finished, 0);
+
+ spin_lock(&call_lock);
+ call_data = &data;
+ mb();
+
+ /* 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)
+ while (atomic_read(&data.finished) != cpus)
+ cpu_relax();
+ spin_unlock(&call_lock);
+
+ return 0;
+}
+
+static void stop_this_cpu (void * dummy)
+{
+ /*
+ * Remove this CPU:
+ */
+ cpu_clear(smp_processor_id(), cpu_online_map);
+ local_irq_disable();
+ disable_local_APIC();
+ if (cpu_data[smp_processor_id()].hlt_works_ok)
+ for(;;) __asm__("hlt");
+ for (;;);
+}
+
+/*
+ * this function calls the 'stop' function on all other CPUs in the system.
+ */
+
+void smp_send_stop(void)
+{
+ smp_call_function(stop_this_cpu, NULL, 1, 0);
+
+ 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.
+ */
+fastcall void smp_reschedule_interrupt(struct pt_regs *regs)
+{
+ ack_APIC_irq();
+}
+
+fastcall void smp_call_function_interrupt(struct pt_regs *regs)
+{
+ 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);
+ }
+}
+