source: trunk/packages/xen-3.1/xen-3.1/xen/arch/ia64/linux-xen/tlb.c @ 34

/*
 * TLB support routines.
 *
 * Copyright (C) 1998-2001, 2003 Hewlett-Packard Co
 *      David Mosberger-Tang <davidm@hpl.hp.com>
 *
 * 08/02/00 A. Mallick <asit.k.mallick@intel.com>
 *              Modified RID allocation for SMP
 *          Goutham Rao <goutham.rao@intel.com>
 *              IPI based ptc implementation and A-step IPI implementation.
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/mm.h>

#include <asm/delay.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
#include <asm/pal.h>
#include <asm/tlbflush.h>

static struct {
        unsigned long mask;     /* mask of supported purge page-sizes */
        unsigned long max_bits; /* log2() of largest supported purge page-size */
} purge;

#ifndef XEN
struct ia64_ctx ia64_ctx = {
        .lock =         SPIN_LOCK_UNLOCKED,
        .next =         1,
        .limit =        (1 << 15) - 1,          /* start out with the safe (architected) limit */
        .max_ctx =      ~0U
};

DEFINE_PER_CPU(u8, ia64_need_tlb_flush);

/*
 * Acquire the ia64_ctx.lock before calling this function!
 */
void
wrap_mmu_context (struct mm_struct *mm)
{
        unsigned long tsk_context, max_ctx = ia64_ctx.max_ctx;
        struct task_struct *tsk;
        int i;

        if (ia64_ctx.next > max_ctx)
                ia64_ctx.next = 300;    /* skip daemons */
        ia64_ctx.limit = max_ctx + 1;

        /*
         * Scan all the task's mm->context and set proper safe range
         */

        read_lock(&tasklist_lock);
  repeat:
        for_each_process(tsk) {
                if (!tsk->mm)
                        continue;
                tsk_context = tsk->mm->context;
                if (tsk_context == ia64_ctx.next) {
                        if (++ia64_ctx.next >= ia64_ctx.limit) {
                                /* empty range: reset the range limit and start over */
                                if (ia64_ctx.next > max_ctx)
                                        ia64_ctx.next = 300;
                                ia64_ctx.limit = max_ctx + 1;
                                goto repeat;
                        }
                }
                if ((tsk_context > ia64_ctx.next) && (tsk_context < ia64_ctx.limit))
                        ia64_ctx.limit = tsk_context;
        }
        read_unlock(&tasklist_lock);
        /* can't call flush_tlb_all() here because of race condition with O(1) scheduler [EF] */
        {
                int cpu = get_cpu(); /* prevent preemption/migration */
                for (i = 0; i < NR_CPUS; ++i)
                        if (cpu_online(i) && (i != cpu))
                                per_cpu(ia64_need_tlb_flush, i) = 1;
                put_cpu();
        }
        local_flush_tlb_all();
}
#endif /* XEN */

void
ia64_global_tlb_purge (unsigned long start, unsigned long end, unsigned long nbits)
{
        static DEFINE_SPINLOCK(ptcg_lock);

        /* HW requires global serialization of ptc.ga.  */
        spin_lock(&ptcg_lock);
        {
                do {
                        /*
                         * Flush ALAT entries also.
                         */
                        ia64_ptcga(start, (nbits<<2));
                        ia64_srlz_i();
                        start += (1UL << nbits);
                } while (start < end);
        }
        spin_unlock(&ptcg_lock);
}

void
local_flush_tlb_all (void)
{
        unsigned long i, j, flags, count0, count1, stride0, stride1, addr;
#ifdef XEN
        /* increment flush clock before mTLB flush */
        u32 flush_time = tlbflush_clock_inc_and_return();
#endif
        addr    = local_cpu_data->ptce_base;
        count0  = local_cpu_data->ptce_count[0];
        count1  = local_cpu_data->ptce_count[1];
        stride0 = local_cpu_data->ptce_stride[0];
        stride1 = local_cpu_data->ptce_stride[1];

        local_irq_save(flags);
        for (i = 0; i < count0; ++i) {
                for (j = 0; j < count1; ++j) {
                        ia64_ptce(addr);
                        addr += stride1;
                }
                addr += stride0;
        }
        local_irq_restore(flags);
        ia64_srlz_i();                  /* srlz.i implies srlz.d */
#ifdef XEN
        /* update after mTLB flush. */
        tlbflush_update_time(&__get_cpu_var(tlbflush_time), flush_time);
#endif
}
EXPORT_SYMBOL(local_flush_tlb_all);

#ifndef XEN
void
flush_tlb_range (struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
        struct mm_struct *mm = vma->vm_mm;
        unsigned long size = end - start;
        unsigned long nbits;

        if (mm != current->active_mm) {
                /* this does happen, but perhaps it's not worth optimizing for? */
#ifdef CONFIG_SMP
                flush_tlb_all();
#else
                mm->context = 0;
#endif
                return;
        }

        nbits = ia64_fls(size + 0xfff);
        while (unlikely (((1UL << nbits) & purge.mask) == 0) && (nbits < purge.max_bits))
                ++nbits;
        if (nbits > purge.max_bits)
                nbits = purge.max_bits;
        start &= ~((1UL << nbits) - 1);

# ifdef CONFIG_SMP
        platform_global_tlb_purge(start, end, nbits);
# else
        do {
                ia64_ptcl(start, (nbits<<2));
                start += (1UL << nbits);
        } while (start < end);
# endif

        ia64_srlz_i();                  /* srlz.i implies srlz.d */
}
EXPORT_SYMBOL(flush_tlb_range);
#endif

void __devinit
ia64_tlb_init (void)
{
#ifndef XEN
        ia64_ptce_info_t ptce_info;
#else
        ia64_ptce_info_t ptce_info = { 0 };
#endif
        unsigned long tr_pgbits;
        long status;

        if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
                printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld;"
                       "defaulting to architected purge page-sizes.\n", status);
                purge.mask = 0x115557000UL;
        }
        purge.max_bits = ia64_fls(purge.mask);

        ia64_get_ptce(&ptce_info);
        local_cpu_data->ptce_base = ptce_info.base;
        local_cpu_data->ptce_count[0] = ptce_info.count[0];
        local_cpu_data->ptce_count[1] = ptce_info.count[1];
        local_cpu_data->ptce_stride[0] = ptce_info.stride[0];
        local_cpu_data->ptce_stride[1] = ptce_info.stride[1];

        local_flush_tlb_all();          /* nuke left overs from bootstrapping... */
}