i86pc/vm/hat_kdi.c

	hat_kdi.c revision 7aec1d6e253b21f9e9b7ef68b4d81ab9859b51fe
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*
 * HAT interfaces used by the kernel debugger to interact with the VM system.
 * These interfaces are invoked when the world is stopped.  As such, no blocking
 * operations may be performed.
 */

#include <sys/cpuvar.h>
#include <sys/kdi_impl.h>
#include <sys/errno.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/mman.h>
#include <sys/bootconf.h>
#include <sys/cmn_err.h>
#include <vm/seg_kmem.h>
#include <vm/hat_i86.h>
#include <sys/machsystm.h>

/*
 * The debugger needs direct access to the PTE of one page table entry
 * in order to implement vtop and physical read/writes
 */
extern uintptr_t ptable_va;
static uintptr_t hat_kdi_page = 0;  /* vaddr for phsical page accesses */
static x86pte_t *hat_kdi_pte = NULL;    /* vaddr of pte for hat_kdi_page */
uint_t hat_kdi_use_pae;         /* if 0, use x86pte32_t for pte type */

/*
 * Allocate virtual page to use for kernel debugger accesses to physical memory.
 * This is done very early in boot - before vmem allocator is available, so
 * we use a special hand picked address. (blech) The address is one page
 * above where the hat will put pages for pagetables -- see ptable_alloc() --
 * and is outside of the kernel's address space.
 *
 * We'll pick a new VA after the kernel's hat has been initialized.
 */
void
hat_boot_kdi_init(void)
{

    /*
     * The 1st ptable_va page is for the HAT, we use the 2nd.
     */
    hat_kdi_page = ptable_va + MMU_PAGESIZE;
#if defined(__amd64)
    hat_kdi_use_pae = 1;
#elif defined(__i386)
    hat_kdi_use_pae = 0;
#endif
}

/*
 * Switch to using a page in the kernel's va range for physical memory access.
 * We need to allocate a virtual page, then permanently map in the page that
 * contains the PTE to it.
 */
void
hat_kdi_init(void)
{
    htable_t *ht;

    /*
     * Get an kernel page VA to use for phys mem access. Then make sure
     * the VA has a page table.
     */
    hat_kdi_use_pae = mmu.pae_hat;
    hat_kdi_page = (uintptr_t)vmem_alloc(heap_arena, PAGESIZE, VM_SLEEP);
    ht = htable_create(kas.a_hat, hat_kdi_page, 0, NULL);

    /*
     * Get an address at which to put the pagetable and devload it.
     */
    hat_kdi_pte = vmem_xalloc(heap_arena, MMU_PAGESIZE, MMU_PAGESIZE, 0,
        0, NULL, NULL, VM_SLEEP);
    hat_devload(kas.a_hat, (caddr_t)hat_kdi_pte, MMU_PAGESIZE, ht->ht_pfn,
        PROT_READ | PROT_WRITE | HAT_NOSYNC | HAT_UNORDERED_OK,
        HAT_LOAD | HAT_LOAD_NOCONSIST);
    hat_kdi_pte = (x86pte_t *)((uintptr_t)hat_kdi_pte +
        (htable_va2entry(hat_kdi_page, ht) << mmu.pte_size_shift));

    HTABLE_INC(ht->ht_valid_cnt);
    htable_release(ht);
}

/*ARGSUSED*/
int
kdi_vtop(uintptr_t va, uint64_t *pap)
{
    uintptr_t vaddr = va;
    size_t  len;
    pfn_t   pfn;
    uint_t  prot;
    int level;
    x86pte_t pte;
    int index;

    /*
     * if the mmu struct isn't relevant yet, we need to probe
     * the boot loader's pagetables.
     */
    if (!khat_running) {
        if (hat_boot_probe(&vaddr, &len, &pfn, &prot) == 0)
            return (ENOENT);
        if (vaddr > va)
            return (ENOENT);
        if (vaddr < va)
            pfn += mmu_btop(va - vaddr);
        *pap = (uint64_t)mmu_ptob(pfn) + (vaddr & MMU_PAGEOFFSET);
        return (0);
    }

    /*
     * We can't go through normal hat routines, so we'll use
     * kdi_pread() to walk the page tables
     */
    *pap = getcr3() & MMU_PAGEMASK;
    for (level = mmu.max_level; ; --level) {
        index = (va >> LEVEL_SHIFT(level)) & (mmu.ptes_per_table - 1);
        *pap += index << mmu.pte_size_shift;
        pte = 0;
        if (kdi_pread((caddr_t)&pte, mmu.pte_size, *pap, &len) != 0)
            return (ENOENT);
        if (pte == 0)
            return (ENOENT);
        if (level > 0 && level <= mmu.max_page_level &&
            (pte & PT_PAGESIZE)) {
            *pap = pte & PT_PADDR_LGPG;
            break;
        } else {
            *pap = pte & PT_PADDR;
            if (level == 0)
                break;
        }
    }
    *pap += va & LEVEL_OFFSET(level);
    return (0);
}

static int
kdi_prw(caddr_t buf, size_t nbytes, uint64_t pa, size_t *ncopiedp, int doread)
{
    size_t  ncopied = 0;
    off_t   pgoff;
    size_t  sz;
    caddr_t va;
    caddr_t from;
    caddr_t to;
    x86pte_t pte;

    /*
     * if this is called before any initialization - fail
     */
    if (hat_kdi_page == 0)
        return (EAGAIN);

    while (nbytes > 0) {
        /*
         * figure out the addresses and construct a minimal PTE
         */
        pgoff = pa & MMU_PAGEOFFSET;
        sz = MIN(nbytes, MMU_PAGESIZE - pgoff);
        va = (caddr_t)hat_kdi_page + pgoff;
        pte = MAKEPTE(btop(pa), 0);
        if (doread) {
            from = va;
            to = buf;
        } else {
            PTE_SET(pte, PT_WRITABLE);
            from = buf;
            to = va;
        }

        /*
         * map the physical page
         */
        if (hat_kdi_pte == NULL)
            (void) hat_boot_remap(hat_kdi_page, btop(pa));
        else if (hat_kdi_use_pae)
            *hat_kdi_pte = pte;
        else
            *(x86pte32_t *)hat_kdi_pte = pte;
        mmu_tlbflush_entry((caddr_t)hat_kdi_page);

        bcopy(from, to, sz);

        /*
         * erase the mapping
         */
        if (hat_kdi_pte == NULL)
            hat_boot_demap(hat_kdi_page);
        else if (hat_kdi_use_pae)
            *hat_kdi_pte = 0;
        else
            *(x86pte32_t *)hat_kdi_pte = 0;
        mmu_tlbflush_entry((caddr_t)hat_kdi_page);

        buf += sz;
        pa += sz;
        nbytes -= sz;
        ncopied += sz;
    }

    if (ncopied == 0)
        return (ENOENT);

    *ncopiedp = ncopied;
    return (0);
}

int
kdi_pread(caddr_t buf, size_t nbytes, uint64_t addr, size_t *ncopiedp)
{
    return (kdi_prw(buf, nbytes, addr, ncopiedp, 1));
}

int
kdi_pwrite(caddr_t buf, size_t nbytes, uint64_t addr, size_t *ncopiedp)
{
    return (kdi_prw(buf, nbytes, addr, ncopiedp, 0));
}


/*
 * Return the number of bytes, relative to the beginning of a given range, that
 * are non-toxic (can be read from and written to with relative impunity).
 */
/*ARGSUSED*/
size_t
kdi_range_is_nontoxic(uintptr_t va, size_t sz, int write)
{
#ifdef __amd64
    extern uintptr_t toxic_addr;
    extern size_t   toxic_size;

    /*
     * Check 64 bit toxic range.
     */
    if (toxic_addr != 0 &&
        va + sz >= toxic_addr &&
        va < toxic_addr + toxic_size)
        return (va < toxic_addr ? toxic_addr - va : 0);

    /*
     * avoid any Virtual Address hole
     */
    if (va + sz >= hole_start && va < hole_end)
        return (va < hole_start ? hole_start - va : 0);

    return (sz);

#else
    extern void *device_arena_contains(void *, size_t, size_t *);
    uintptr_t v;

    v = (uintptr_t)device_arena_contains((void *)va, sz, NULL);
    if (v == 0)
        return (sz);
    else if (v <= va)
        return (0);
    else
        return (v - va);

#endif
}

void
hat_kdi_fini(void)
{
}