common/os/bp_map.c

	bp_map.c revision 36945f796054e8cb46d88ec0a84213123cf2b036
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/mman.h>
#include <sys/buf.h>
#include <sys/vmem.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/machparam.h>
#include <vm/page.h>
#include <vm/seg_kmem.h>
#include <vm/seg_kpm.h>

#ifdef __sparc
#include <sys/cpu_module.h>
#define BP_FLUSH(addr, size)    flush_instr_mem((void *)addr, size);
#else
#define BP_FLUSH(addr, size)
#endif

int bp_force_copy = 0;
typedef enum {
    BP_COPYIN   = 0,
    BP_COPYOUT  = 1
} bp_copydir_t;
static int bp_copy_common(bp_copydir_t dir, struct buf *bp, void *driverbuf,
    offset_t offset, size_t size);

static vmem_t *bp_map_arena;
static size_t bp_align;
static uint_t bp_devload_flags = PROT_READ | PROT_WRITE | HAT_NOSYNC;
int bp_max_cache = 1 << 17;     /* 128K default; tunable */
int bp_mapin_kpm_enable = 1;    /* enable default; tunable */

static void *
bp_vmem_alloc(vmem_t *vmp, size_t size, int vmflag)
{
    return (vmem_xalloc(vmp, size, bp_align, 0, 0, NULL, NULL, vmflag));
}

void
bp_init(size_t align, uint_t devload_flags)
{
    bp_align = MAX(align, PAGESIZE);
    bp_devload_flags |= devload_flags;

    if (bp_align <= bp_max_cache)
        bp_map_arena = vmem_create("bp_map", NULL, 0, bp_align,
            bp_vmem_alloc, vmem_free, heap_arena,
            MIN(8 * bp_align, bp_max_cache), VM_SLEEP);
}

/*
 * common routine so can be called with/without VM_SLEEP
 */
void *
bp_mapin_common(struct buf *bp, int flag)
{
    struct as   *as;
    pfn_t       pfnum;
    page_t      *pp;
    page_t      **pplist;
    caddr_t     kaddr;
    caddr_t     addr;
    uintptr_t   off;
    size_t      size;
    pgcnt_t     npages;
    int     color;

    /* return if already mapped in, no pageio/physio, or physio to kas */
    if ((bp->b_flags & B_REMAPPED) ||
        !(bp->b_flags & (B_PAGEIO | B_PHYS)) ||
        (((bp->b_flags & (B_PAGEIO | B_PHYS)) == B_PHYS) &&
        ((bp->b_proc == NULL) || (bp->b_proc->p_as == &kas))))
        return (bp->b_un.b_addr);

    ASSERT((bp->b_flags & (B_PAGEIO | B_PHYS)) != (B_PAGEIO | B_PHYS));

    addr = (caddr_t)bp->b_un.b_addr;
    off = (uintptr_t)addr & PAGEOFFSET;
    size = P2ROUNDUP(bp->b_bcount + off, PAGESIZE);
    npages = btop(size);

    /* Fastpath single page IO to locked memory by using kpm. */
    if ((bp->b_flags & (B_SHADOW | B_PAGEIO)) && (npages == 1) &&
        kpm_enable && bp_mapin_kpm_enable) {
        if (bp->b_flags & B_SHADOW)
            pp = *bp->b_shadow;
        else
            pp = bp->b_pages;
        kaddr = hat_kpm_mapin(pp, NULL);
        bp->b_un.b_addr = kaddr + off;
        bp->b_flags |= B_REMAPPED;
        return (bp->b_un.b_addr);
    }

    /*
     * Allocate kernel virtual space for remapping.
     */
    color = bp_color(bp);
    ASSERT(color < bp_align);

    if (bp_map_arena != NULL) {
        kaddr = (caddr_t)vmem_alloc(bp_map_arena,
            P2ROUNDUP(color + size, bp_align), flag);
        if (kaddr == NULL)
            return (NULL);
        kaddr += color;
    } else {
        kaddr = vmem_xalloc(heap_arena, size, bp_align, color,
            0, NULL, NULL, flag);
        if (kaddr == NULL)
            return (NULL);
    }

    ASSERT(P2PHASE((uintptr_t)kaddr, bp_align) == color);

    /*
     * Map bp into the virtual space we just allocated.
     */
    if (bp->b_flags & B_PAGEIO) {
        pp = bp->b_pages;
        pplist = NULL;
    } else if (bp->b_flags & B_SHADOW) {
        pp = NULL;
        pplist = bp->b_shadow;
    } else {
        pp = NULL;
        pplist = NULL;
        if (bp->b_proc == NULL || (as = bp->b_proc->p_as) == NULL)
            as = &kas;
    }

    bp->b_flags |= B_REMAPPED;
    bp->b_un.b_addr = kaddr + off;

    while (npages-- != 0) {
        if (pp) {
            pfnum = pp->p_pagenum;
            pp = pp->p_next;
        } else if (pplist == NULL) {
            pfnum = hat_getpfnum(as->a_hat,
                (caddr_t)((uintptr_t)addr & MMU_PAGEMASK));
            if (pfnum == PFN_INVALID)
                panic("bp_mapin_common: hat_getpfnum for"
                    " addr %p failed\n", (void *)addr);
            addr += PAGESIZE;
        } else {
            pfnum = (*pplist)->p_pagenum;
            pplist++;
        }

        hat_devload(kas.a_hat, kaddr, PAGESIZE, pfnum,
            bp_devload_flags, HAT_LOAD_LOCK);

        kaddr += PAGESIZE;
    }
    return (bp->b_un.b_addr);
}

/*
 * Convert bp for pageio/physio to a kernel addressable location.
 */
void
bp_mapin(struct buf *bp)
{
    (void) bp_mapin_common(bp, VM_SLEEP);
}

/*
 * Release all the resources associated with a previous bp_mapin() call.
 */
void
bp_mapout(struct buf *bp)
{
    caddr_t     addr;
    uintptr_t   off;
    uintptr_t   base;
    uintptr_t   color;
    size_t      size;
    pgcnt_t     npages;
    page_t      *pp;

    if ((bp->b_flags & B_REMAPPED) == 0)
        return;

    addr = bp->b_un.b_addr;
    off = (uintptr_t)addr & PAGEOFFSET;
    size = P2ROUNDUP(bp->b_bcount + off, PAGESIZE);
    npages = btop(size);

    bp->b_un.b_addr = (caddr_t)off;     /* debugging aid */

    if ((bp->b_flags & (B_SHADOW | B_PAGEIO)) && (npages == 1) &&
        kpm_enable && bp_mapin_kpm_enable) {
        if (bp->b_flags & B_SHADOW)
            pp = *bp->b_shadow;
        else
            pp = bp->b_pages;
        addr = (caddr_t)((uintptr_t)addr & MMU_PAGEMASK);
        hat_kpm_mapout(pp, NULL, addr);
        bp->b_flags &= ~B_REMAPPED;
        return;
    }

    base = (uintptr_t)addr & MMU_PAGEMASK;
    BP_FLUSH(base, size);
    hat_unload(kas.a_hat, (void *)base, size,
        HAT_UNLOAD_NOSYNC | HAT_UNLOAD_UNLOCK);
    if (bp_map_arena != NULL) {
        color = P2PHASE(base, bp_align);
        vmem_free(bp_map_arena, (void *)(base - color),
            P2ROUNDUP(color + size, bp_align));
    } else
        vmem_free(heap_arena, (void *)base, size);
    bp->b_flags &= ~B_REMAPPED;
}

/*
 * copy data from a KVA into a buf_t which may not be mapped in. offset
 * is relative to the buf_t only.
 */
int
bp_copyout(void *driverbuf, struct buf *bp, offset_t offset, size_t size)
{
    return (bp_copy_common(BP_COPYOUT, bp, driverbuf, offset, size));
}

/*
 * copy data from a buf_t which may not be mapped in, into a KVA.. offset
 * is relative to the buf_t only.
 */
int
bp_copyin(struct buf *bp, void *driverbuf, offset_t offset, size_t size)
{
    return (bp_copy_common(BP_COPYIN, bp, driverbuf, offset, size));
}


#define BP_COPY(dir, driverbuf, baddr, sz)  \
    (dir == BP_COPYIN) ? \
    bcopy(baddr, driverbuf, sz) :  bcopy(driverbuf, baddr, sz)

static int
bp_copy_common(bp_copydir_t dir, struct buf *bp, void *driverbuf,
    offset_t offset, size_t size)
{
    page_t **pplist;
    uintptr_t poff;
    uintptr_t voff;
    struct as *as;
    caddr_t kaddr;
    caddr_t addr;
    page_t *page;
    size_t psize;
    page_t *pp;
    pfn_t pfn;


    ASSERT((offset + size) <= bp->b_bcount);

    /* if the buf_t already has a KVA, just do a bcopy */
    if (!(bp->b_flags & (B_PHYS | B_PAGEIO))) {
        BP_COPY(dir, driverbuf, bp->b_un.b_addr + offset, size);
        return (0);
    }

    /* if we don't have kpm enabled, we need to do the slow path */
    if (!kpm_enable || bp_force_copy) {
        bp_mapin(bp);
        BP_COPY(dir, driverbuf, bp->b_un.b_addr + offset, size);
        bp_mapout(bp);
        return (0);
    }

    /*
     * kpm is enabled, and we need to map in the buf_t for the copy
     */

    /* setup pp, plist, and make sure 'as' is right */
    if (bp->b_flags & B_PAGEIO) {
        pp = bp->b_pages;
        pplist = NULL;
    } else if (bp->b_flags & B_SHADOW) {
        pp = NULL;
        pplist = bp->b_shadow;
    } else {
        pp = NULL;
        pplist = NULL;
        if (bp->b_proc == NULL || (as = bp->b_proc->p_as) == NULL) {
            as = &kas;
        }
    }

    /*
     * locals for the address, the offset into the first page, and the
     * size of the first page we are going to copy.
     */
    addr = (caddr_t)bp->b_un.b_addr;
    poff = (uintptr_t)addr & PAGEOFFSET;
    psize = MIN(PAGESIZE - poff, size);

    /*
     * we always start with a 0 offset into the driverbuf provided. The
     * offset passed in only applies to the buf_t.
     */
    voff = 0;

    /* Loop until we've copied al the data */
    while (size > 0) {

        /*
         * for a pp or pplist, get the pfn, then go to the next page_t
         * for the next time around the loop.
         */
        if (pp) {
            page = pp;
            pp = pp->p_next;
        } else if (pplist != NULL) {
            page = (*pplist);
            pplist++;

        /*
         * We have a user VA. If we are going to copy this page, (e.g.
         * the offset into the buf_t where we start to copy is
         * within this page), get the pfn. Don't waste the cycles
         * getting the pfn if we're not copying this page.
         */
        } else if (offset < psize) {
            pfn = hat_getpfnum(as->a_hat,
                (caddr_t)((uintptr_t)addr & PAGEMASK));
            if (pfn == PFN_INVALID) {
                return (-1);
            }
            page = page_numtopp_nolock(pfn);
            addr += psize - offset;
        } else {
            addr += psize;
        }

        /*
         * if we have an initial offset into the buf_t passed in,
         * and it falls within the current page, account for it in
         * the page size (how much we will copy) and the offset into the
         * page (where we'll start copying from).
         */
        if ((offset > 0) && (offset < psize)) {
            psize -= offset;
            poff += offset;
            offset = 0;

        /*
         * if we have an initial offset into the buf_t passed in,
         * and it's not within the current page, skip this page.
         * We don't have to worry about the first page offset and size
         * anymore. psize will normally be PAGESIZE now unless we are
         * on the last page.
         */
        } else if (offset >= psize) {
            offset -= psize;
            psize = MIN(PAGESIZE, size);
            poff = 0;
            continue;
        }

        /*
         * get a kpm mapping to the page, them copy in/out of the
         * page. update size left and offset into the driverbuf passed
         * in for the next time around the loop.
         */
        kaddr = hat_kpm_mapin(page, NULL) + poff;
        BP_COPY(dir, (void *)((uintptr_t)driverbuf + voff), kaddr,
            psize);
        hat_kpm_mapout(page, NULL, kaddr - poff);

        size -= psize;
        voff += psize;

        poff = 0;
        psize = MIN(PAGESIZE, size);
    }

    return (0);
}