x86: make x86_32 use tlb_64.c

Impact: less contention when issuing invalidate IPI, cleanup

Make x86_32 use the same tlb code as 64bit.  The 64bit code uses
multiple IPI vectors for tlb shootdown to reduce contention.  This
patch makes x86_32 allocate the same 8 IPIs as x86_64 and share the
code paths.

Note that the usage of asmlinkage is inconsistent for x86_32 and 64
and calls for further cleanup.  This has been noted with a FIXME
comment in tlb_64.c.

Signed-off-by: Tejun Heo <tj@kernel.org>

5 files changed, 25 insertions, 245 deletions

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index eb074530c7d3..a62a15c22227 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -58,7 +58,7 @@ obj-$(CONFIG_PCI)		+= early-quirks.o
 apm-y                           := apm_32.o
 obj-$(CONFIG_APM)               += apm.o
 obj-$(CONFIG_X86_SMP)           += smp.o
-obj-$(CONFIG_X86_SMP)           += smpboot.o tsc_sync.o ipi.o tlb_$(BITS).o
+obj-$(CONFIG_X86_SMP)           += smpboot.o tsc_sync.o ipi.o tlb_64.o
 obj-$(CONFIG_X86_32_SMP)        += smpcommon.o
 obj-$(CONFIG_X86_64_SMP)        += tsc_sync.o smpcommon.o
 obj-$(CONFIG_X86_TRAMPOLINE)    += trampoline_$(BITS).o
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 46469029e9d3..a0b91aac72a1 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -672,7 +672,7 @@ common_interrupt:
 ENDPROC(common_interrupt)
         CFI_ENDPROC
 
-#define BUILD_INTERRUPT(name, nr)       \
+#define BUILD_INTERRUPT3(name, nr, fn)  \
 ENTRY(name)                             \
         RING0_INT_FRAME;                \
         pushl $~(nr);                   \
@@ -680,11 +680,13 @@ ENTRY(name)				\
         SAVE_ALL;                       \
         TRACE_IRQS_OFF                  \
         movl %esp,%eax;                 \
-        call smp_##name;                \
+        call fn;                        \
         jmp ret_from_intr;              \
         CFI_ENDPROC;                    \
 ENDPROC(name)
 
+#define BUILD_INTERRUPT(name, nr)       BUILD_INTERRUPT3(name, nr, smp_##name)
+
 /* The include is where all of the SMP etc. interrupts come from */
 #include "entry_arch.h"
 
diff --git a/arch/x86/kernel/irqinit_32.c b/arch/x86/kernel/irqinit_32.c
index 1507ad4e674d..bf629cadec1a 100644
--- a/arch/x86/kernel/irqinit_32.c
+++ b/arch/x86/kernel/irqinit_32.c
@@ -149,8 +149,15 @@ void __init native_init_IRQ(void)
          */
         alloc_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);
 
-        /* IPI for invalidation */
-        alloc_intr_gate(INVALIDATE_TLB_VECTOR, invalidate_interrupt);
+        /* IPIs for invalidation */
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+0, invalidate_interrupt0);
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+1, invalidate_interrupt1);
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+2, invalidate_interrupt2);
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+3, invalidate_interrupt3);
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+4, invalidate_interrupt4);
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+5, invalidate_interrupt5);
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+6, invalidate_interrupt6);
+        alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+7, invalidate_interrupt7);
 
         /* IPI for generic function call */
         alloc_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
diff --git a/arch/x86/kernel/tlb_32.c b/arch/x86/kernel/tlb_32.c
deleted file mode 100644
index 93fcb05c7d43..000000000000
--- a/arch/x86/kernel/tlb_32.c
+++ /dev/null
@@ -1,239 +0,0 @@
-#include <linux/spinlock.h>
-#include <linux/cpu.h>
-#include <linux/interrupt.h>
-
-#include <asm/tlbflush.h>
-
-DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate)
-                        = { &init_mm, 0, };
-
-/* must come after the send_IPI functions above for inlining */
-#include <mach_ipi.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_var_t flush_cpumask;
-static struct mm_struct *flush_mm;
-static unsigned long flush_va;
-static DEFINE_SPINLOCK(tlbstate_lock);
-
-/*
- * 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..
- */
-void leave_mm(int cpu)
-{
-        BUG_ON(percpu_read(cpu_tlbstate.state) == TLBSTATE_OK);
-        cpu_clear(cpu, percpu_read(cpu_tlbstate.active_mm)->cpu_vm_mask);
-        load_cr3(swapper_pg_dir);
-}
-EXPORT_SYMBOL_GPL(leave_mm);
-
-/*
- *
- * 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_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.
- *
- * Interrupts are disabled.
- */
-
-void smp_invalidate_interrupt(struct pt_regs *regs)
-{
-        unsigned int cpu;
-
-        cpu = smp_processor_id();
-
-        if (!cpumask_test_cpu(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 == percpu_read(cpu_tlbstate.active_mm)) {
-                if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) {
-                        if (flush_va == TLB_FLUSH_ALL)
-                                local_flush_tlb();
-                        else
-                                __flush_tlb_one(flush_va);
-                } else
-                        leave_mm(cpu);
-        }
-out:
-        ack_APIC_irq();
-        smp_mb__before_clear_bit();
-        cpumask_clear_cpu(cpu, flush_cpumask);
-        smp_mb__after_clear_bit();
-        inc_irq_stat(irq_tlb_count);
-}
-
-void native_flush_tlb_others(const struct cpumask *cpumask,
-                             struct mm_struct *mm, unsigned long va)
-{
-        /*
-         * - mask must exist :)
-         */
-        BUG_ON(cpumask_empty(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.
-         * AK: x86-64 has a faster method that could be ported.
-         */
-        spin_lock(&tlbstate_lock);
-
-        cpumask_andnot(flush_cpumask, cpumask, cpumask_of(smp_processor_id()));
-#ifdef CONFIG_HOTPLUG_CPU
-        /* If a CPU which we ran on has gone down, OK. */
-        cpumask_and(flush_cpumask, flush_cpumask, cpu_online_mask);
-        if (unlikely(cpumask_empty(flush_cpumask))) {
-                spin_unlock(&tlbstate_lock);
-                return;
-        }
-#endif
-        flush_mm = mm;
-        flush_va = va;
-
-        /*
-         * Make the above memory operations globally visible before
-         * sending the IPI.
-         */
-        smp_mb();
-        /*
-         * We have to send the IPI only to
-         * CPUs affected.
-         */
-        send_IPI_mask(flush_cpumask, INVALIDATE_TLB_VECTOR);
-
-        while (!cpumask_empty(flush_cpumask))
-                /* nothing. lockup detection does not belong here */
-                cpu_relax();
-
-        flush_mm = NULL;
-        flush_va = 0;
-        spin_unlock(&tlbstate_lock);
-}
-
-void flush_tlb_current_task(void)
-{
-        struct mm_struct *mm = current->mm;
-
-        preempt_disable();
-
-        local_flush_tlb();
-        if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids)
-                flush_tlb_others(&mm->cpu_vm_mask, mm, TLB_FLUSH_ALL);
-        preempt_enable();
-}
-
-void flush_tlb_mm(struct mm_struct *mm)
-{
-
-        preempt_disable();
-
-        if (current->active_mm == mm) {
-                if (current->mm)
-                        local_flush_tlb();
-                else
-                        leave_mm(smp_processor_id());
-        }
-        if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids)
-                flush_tlb_others(&mm->cpu_vm_mask, mm, TLB_FLUSH_ALL);
-
-        preempt_enable();
-}
-
-void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
-{
-        struct mm_struct *mm = vma->vm_mm;
-
-        preempt_disable();
-
-        if (current->active_mm == mm) {
-                if (current->mm)
-                        __flush_tlb_one(va);
-                 else
-                        leave_mm(smp_processor_id());
-        }
-
-        if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids)
-                flush_tlb_others(&mm->cpu_vm_mask, mm, va);
-        preempt_enable();
-}
-
-static void do_flush_tlb_all(void *info)
-{
-        unsigned long cpu = smp_processor_id();
-
-        __flush_tlb_all();
-        if (percpu_read(cpu_tlbstate.state) == TLBSTATE_LAZY)
-                leave_mm(cpu);
-}
-
-void flush_tlb_all(void)
-{
-        on_each_cpu(do_flush_tlb_all, NULL, 1);
-}
-
-static int init_flush_cpumask(void)
-{
-        alloc_cpumask_var(&flush_cpumask, GFP_KERNEL);
-        return 0;
-}
-early_initcall(init_flush_cpumask);
diff --git a/arch/x86/kernel/tlb_64.c b/arch/x86/kernel/tlb_64.c
index 19ac661422f7..b3ca1b940654 100644
--- a/arch/x86/kernel/tlb_64.c
+++ b/arch/x86/kernel/tlb_64.c
@@ -113,7 +113,17 @@ EXPORT_SYMBOL_GPL(leave_mm);
  * Interrupts are disabled.
  */
 
-asmlinkage void smp_invalidate_interrupt(struct pt_regs *regs)
+/*
+ * FIXME: use of asmlinkage is not consistent.  On x86_64 it's noop
+ * but still used for documentation purpose but the usage is slightly
+ * inconsistent.  On x86_32, asmlinkage is regparm(0) but interrupt
+ * entry calls in with the first parameter in %eax.  Maybe define
+ * intrlinkage?
+ */
+#ifdef CONFIG_X86_64
+asmlinkage
+#endif
+void smp_invalidate_interrupt(struct pt_regs *regs)
 {
         unsigned int cpu;
         unsigned int sender;