/*      $NetBSD: copyout.c,v 1.10 2022/05/22 11:27:34 andvar Exp $      */

/*-
 * Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Raytheon BBN Technologies Corp and Defense Advanced Research Projects
 * Agency and which was developed by Matt Thomas of 3am Software Foundry.
 *
 * This material is based upon work supported by the Defense Advanced Research
 * Projects Agency and Space and Naval Warfare Systems Center, Pacific, under
 * Contract No. N66001-09-C-2073.
 * Approved for Public Release, Distribution Unlimited
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#define __UFETCHSTORE_PRIVATE

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: copyout.c,v 1.10 2022/05/22 11:27:34 andvar Exp $");

#include <sys/param.h>
#include <sys/lwp.h>
#include <sys/systm.h>

#include <powerpc/pcb.h>

#include <powerpc/booke/cpuvar.h>

static inline void
copyout_uint8(uint8_t *udaddr, uint8_t data, register_t ds_msr)
{
        register_t msr;
        __asm volatile(
                "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "stb    %[data],0(%[udaddr])"           /* store user byte */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr)
            : [ds_msr] "r" (ds_msr), [data] "r" (data), [udaddr] "b" (udaddr));
}

static inline void
copyout_uint16(uint16_t *udaddr, uint8_t data, register_t ds_msr)
{
        register_t msr;
        __asm volatile(
                "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "sth    %[data],0(%[udaddr])"           /* store user half */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr)
            : [ds_msr] "r" (ds_msr), [data] "r" (data), [udaddr] "b" (udaddr));
}

static inline void
copyout_uint32(uint32_t * const udaddr, uint32_t data, register_t ds_msr)
{
        register_t msr;
        __asm volatile(
                "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "stw    %[data],0(%[udaddr])"           /* store user data */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr)
            : [ds_msr] "r" (ds_msr), [data] "r" (data), [udaddr] "b" (udaddr));
}

#if 0
static inline void
copyout_le32(uint32_t * const udaddr, uint32_t data, register_t ds_msr)
{
        register_t msr;
        __asm volatile(
                "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "stwbrx %[data],0,%[udaddr]"            /* store user data */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr)
            : [ds_msr] "r" (ds_msr), [data] "r" (data), [udaddr] "b" (udaddr));
}

static inline void
copyout_le32_with_mask(uint32_t * const udaddr, uint32_t data,
        uint32_t mask, register_t ds_msr)
{
        register_t msr;
        uint32_t tmp;
        KASSERT((data & ~mask) == 0);
        __asm volatile(
                "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "lwbrx  %[tmp],0,%[udaddr]"             /* fetch user data */
        "\n\t"  "andc   %[tmp],%[tmp],%[mask]"          /* mask out new data */
        "\n\t"  "or     %[tmp],%[tmp],%[data]"          /* merge new data */
        "\n\t"  "stwbrx %[tmp],0,%[udaddr]"             /* store user data */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr), [tmp] "=&r" (tmp)
            : [ds_msr] "r" (ds_msr), [data] "r" (data),
              [mask] "r" (mask), [udaddr] "b" (udaddr));
}
#endif

static inline void
copyout_16uint8s(const uint8_t *ksaddr8, uint8_t *udaddr8, register_t ds_msr)
{
        register_t msr;
        __asm volatile(
                "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "stb    %[data0],0(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data1],1(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data2],2(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data3],3(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data4],4(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data5],5(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data6],6(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data7],7(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data8],8(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data9],9(%[udaddr8])"         /* store user data */
        "\n\t"  "stb    %[data10],10(%[udaddr8])"       /* store user data */
        "\n\t"  "stb    %[data11],11(%[udaddr8])"       /* store user data */
        "\n\t"  "stb    %[data12],12(%[udaddr8])"       /* store user data */
        "\n\t"  "stb    %[data13],13(%[udaddr8])"       /* store user data */
        "\n\t"  "stb    %[data14],14(%[udaddr8])"       /* store user data */
        "\n\t"  "stb    %[data15],15(%[udaddr8])"       /* store user data */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr)
            : [ds_msr] "r" (ds_msr), [udaddr8] "b" (udaddr8),
              [data0] "r" (ksaddr8[0]), [data1] "r" (ksaddr8[1]),
              [data2] "r" (ksaddr8[2]), [data3] "r" (ksaddr8[3]),
              [data4] "r" (ksaddr8[4]), [data5] "r" (ksaddr8[5]),
              [data6] "r" (ksaddr8[6]), [data7] "r" (ksaddr8[7]),
              [data8] "r" (ksaddr8[8]), [data9] "r" (ksaddr8[9]),
              [data10] "r" (ksaddr8[10]), [data11] "r" (ksaddr8[11]),
              [data12] "r" (ksaddr8[12]), [data13] "r" (ksaddr8[13]),
              [data14] "r" (ksaddr8[14]), [data15] "r" (ksaddr8[15]));
}

static inline void
copyout_8uint32s(const uint32_t * const ksaddr32, uint32_t * const udaddr32,
        const register_t ds_msr, const size_t line_mask)
{
        register_t msr;
        register_t tmp;
        __asm volatile(
                "and.   %[tmp],%[line_mask],%[udaddr32]"
        "\n\t"  "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "bne    0,1f"
        "\n\t"  "dcba   0,%[udaddr32]"
        "\n"    "1:"
        "\n\t"  "stw    %[data0],0(%[udaddr32])"        /* store user data */
        "\n\t"  "stw    %[data1],4(%[udaddr32])"        /* store user data */
        "\n\t"  "stw    %[data2],8(%[udaddr32])"        /* store user data */
        "\n\t"  "stw    %[data3],12(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data4],16(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data5],20(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data6],24(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data7],28(%[udaddr32])"       /* store user data */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr), [tmp] "=&r" (tmp)
            : [ds_msr] "r" (ds_msr), [udaddr32] "b" (udaddr32),
              [line_mask] "r" (line_mask),
              [data0] "r" (ksaddr32[0]), [data1] "r" (ksaddr32[1]),
              [data2] "r" (ksaddr32[2]), [data3] "r" (ksaddr32[3]),
              [data4] "r" (ksaddr32[4]), [data5] "r" (ksaddr32[5]),
              [data6] "r" (ksaddr32[6]), [data7] "r" (ksaddr32[7])
            : "cr0");
}

static inline void
copyout_16uint32s(const uint32_t * const ksaddr32, uint32_t * const udaddr32,
        const register_t ds_msr, const size_t line_mask)
{
        KASSERT(((uintptr_t)udaddr32 & line_mask) == 0);
        register_t msr;
        register_t tmp;
        __asm volatile(
                "and.   %[tmp],%[line_mask],%[udaddr32]"
        "\n\t"  "cmplwi 2,%[line_size],32"
        "\n\t"  "mfmsr  %[msr]"                         /* Save MSR */
        "\n\t"  "mtmsr  %[ds_msr]; sync; isync"         /* DS on */
        "\n\t"  "bne    0,1f"
        "\n\t"  "dcba   0,%[udaddr32]"
        "\n\t"  "bne    2,1f"
        "\n\t"  "dcba   %[line_size],%[udaddr32]"
        "\n"    "1:"
        "\n\t"  "stw    %[data0],0(%[udaddr32])"        /* store user data */
        "\n\t"  "stw    %[data1],4(%[udaddr32])"        /* store user data */
        "\n\t"  "stw    %[data2],8(%[udaddr32])"        /* store user data */
        "\n\t"  "stw    %[data3],12(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data4],16(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data5],20(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data6],24(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data7],28(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data8],32(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data9],36(%[udaddr32])"       /* store user data */
        "\n\t"  "stw    %[data10],40(%[udaddr32])"      /* store user data */
        "\n\t"  "stw    %[data11],44(%[udaddr32])"      /* store user data */
        "\n\t"  "stw    %[data12],48(%[udaddr32])"      /* store user data */
        "\n\t"  "stw    %[data13],52(%[udaddr32])"      /* store user data */
        "\n\t"  "stw    %[data14],56(%[udaddr32])"      /* store user data */
        "\n\t"  "stw    %[data15],60(%[udaddr32])"      /* store user data */
        "\n\t"  "mtmsr  %[msr]; sync; isync"            /* DS off */
            : [msr] "=&r" (msr), [tmp] "=&r" (tmp)
            : [ds_msr] "r" (ds_msr), [udaddr32] "b" (udaddr32),
              [line_size] "r" (line_mask + 1), [line_mask] "r" (line_mask),
              [data0] "r" (ksaddr32[0]), [data1] "r" (ksaddr32[1]),
              [data2] "r" (ksaddr32[2]), [data3] "r" (ksaddr32[3]),
              [data4] "r" (ksaddr32[4]), [data5] "r" (ksaddr32[5]),
              [data6] "r" (ksaddr32[6]), [data7] "r" (ksaddr32[7]),
              [data8] "r" (ksaddr32[8]), [data9] "r" (ksaddr32[9]),
              [data10] "r" (ksaddr32[10]), [data11] "r" (ksaddr32[11]),
              [data12] "r" (ksaddr32[12]), [data13] "r" (ksaddr32[13]),
              [data14] "r" (ksaddr32[14]), [data15] "r" (ksaddr32[15])
            : "cr0", "cr2");
}

static inline void
copyout_uint8s(vaddr_t ksaddr, vaddr_t udaddr, size_t len, register_t ds_msr)
{
        const uint8_t *ksaddr8 = (void *)ksaddr;
        uint8_t *udaddr8 = (void *)udaddr;

        __builtin_prefetch(ksaddr8, 0, 1);

        for (; len >= 16; len -= 16, ksaddr8 += 16, udaddr8 += 16) {
                __builtin_prefetch(ksaddr8 + 16, 0, 1);
                copyout_16uint8s(ksaddr8, udaddr8, ds_msr);
        }

        while (len-- > 0) {
                copyout_uint8(udaddr8++, *ksaddr8++, ds_msr);
        }
}

static inline void
copyout_uint32s(vaddr_t ksaddr, vaddr_t udaddr, size_t len, register_t ds_msr)
{
        const size_t line_size = curcpu()->ci_ci.dcache_line_size;
        const size_t line_mask = line_size - 1;
        const size_t udalignment = udaddr & line_mask;
        KASSERT((ksaddr & 3) == 0);
        KASSERT((udaddr & 3) == 0);
        const uint32_t *ksaddr32 = (void *)ksaddr;
        uint32_t *udaddr32 = (void *)udaddr;
        len >>= 2;
        __builtin_prefetch(ksaddr32, 0, 1);
        if (udalignment != 0 && udalignment + 4*len > line_size) {
                size_t slen = (line_size - udalignment) >> 2;
                len -= slen;
                for (; slen >= 8; ksaddr32 += 8, udaddr32 += 8, slen -= 8) {
                        copyout_8uint32s(ksaddr32, udaddr32, ds_msr, line_mask);
                }
                while (slen-- > 0) {
                        copyout_uint32(udaddr32++, *ksaddr32++, ds_msr);
                }
                if (len == 0)
                        return;
        }
        __builtin_prefetch(ksaddr32, 0, 1);
        while (len >= 16) {
                __builtin_prefetch(ksaddr32 + 8, 0, 1);
                __builtin_prefetch(ksaddr32 + 16, 0, 1);
                copyout_16uint32s(ksaddr32, udaddr32, ds_msr, line_mask);
                ksaddr32 += 16, udaddr32 += 16, len -= 16;
        }
        KASSERT(len <= 16);
        if (len >= 8) {
                __builtin_prefetch(ksaddr32 + 8, 0, 1);
                copyout_8uint32s(ksaddr32, udaddr32, ds_msr, line_mask);
                ksaddr32 += 8, udaddr32 += 8, len -= 8;
        }
        while (len-- > 0) {
                copyout_uint32(udaddr32++, *ksaddr32++, ds_msr);
        }
}

int
_ustore_8(uint8_t *vusaddr, uint8_t val)
{
        struct pcb * const pcb = lwp_getpcb(curlwp);
        struct faultbuf env;

        if (setfault(&env) != 0) {
                pcb->pcb_onfault = NULL;
                return EFAULT;
        }

        copyout_uint8(vusaddr, val, mfmsr() | PSL_DS);

        pcb->pcb_onfault = NULL;

        return 0;
}

int
_ustore_16(uint16_t *vusaddr, uint16_t val)
{
        struct pcb * const pcb = lwp_getpcb(curlwp);
        struct faultbuf env;

        if (setfault(&env) != 0) {
                pcb->pcb_onfault = NULL;
                return EFAULT;
        }

        copyout_uint16(vusaddr, val, mfmsr() | PSL_DS);

        pcb->pcb_onfault = NULL;

        return 0;
}

int
_ustore_32(uint32_t *vusaddr, uint32_t val)
{
        struct pcb * const pcb = lwp_getpcb(curlwp);
        struct faultbuf env;

        if (setfault(&env) != 0) {
                pcb->pcb_onfault = NULL;
                return EFAULT;
        }

        copyout_uint32(vusaddr, val, mfmsr() | PSL_DS);

        pcb->pcb_onfault = NULL;

        return 0;
}

int
copyout(const void *vksaddr, void *vudaddr, size_t len)
{
        struct pcb * const pcb = lwp_getpcb(curlwp);
        struct faultbuf env;
        vaddr_t udaddr = (vaddr_t) vudaddr;
        vaddr_t ksaddr = (vaddr_t) vksaddr;

        if (__predict_false(len == 0)) {
                return 0;
        }

        const register_t ds_msr = mfmsr() | PSL_DS;

        int rv = setfault(&env);
        if (rv != 0) {
                pcb->pcb_onfault = NULL;
                return rv;
        }

        if (__predict_false(len < 4)) {
                copyout_uint8s(ksaddr, udaddr, len, ds_msr);
                pcb->pcb_onfault = NULL;
                return 0;
        }

        const size_t alignment = (udaddr ^ ksaddr) & 3;
        if (__predict_true(alignment == 0)) {
                size_t slen;
                if (__predict_false(ksaddr & 3)) {
                        slen = 4 - (ksaddr & 3);
                        copyout_uint8s(ksaddr, udaddr, slen, ds_msr);
                        udaddr += slen, ksaddr += slen, len -= slen;
                }
                slen = len & ~3;
                if (__predict_true(slen >= 4)) {
                        copyout_uint32s(ksaddr, udaddr, slen, ds_msr);
                        udaddr += slen, ksaddr += slen, len -= slen;
                }
        }

        if (len > 0) {
                copyout_uint8s(ksaddr, udaddr, len, ds_msr);
        }
        pcb->pcb_onfault = NULL;
        return 0;
}

#if 1
int
copyoutstr(const void *ksaddr, void *udaddr, size_t len, size_t *done)
{
        struct pcb * const pcb = lwp_getpcb(curlwp);
        struct faultbuf env;
        int rv;

        if (__predict_false(len == 0)) {
                if (done)
                        *done = 0;
                return 0;
        }

        rv = setfault(&env);
        if (rv != 0) {
                pcb->pcb_onfault = NULL;
                if (done)
                        *done = 0;
                return rv;
        }

        const register_t ds_msr = mfmsr() | PSL_DS;
        const uint8_t *ksaddr8 = ksaddr;
        size_t copylen = 0;

        uint8_t *udaddr8 = (void *)udaddr;

        while (copylen++ < len) {
                const uint8_t data = *ksaddr8++;
                copyout_uint8(udaddr8++, data, ds_msr);
                if (data == 0)
                        goto out;
        }
        rv = ENAMETOOLONG;

out:
        pcb->pcb_onfault = NULL;
        if (done)
                *done = copylen;
        return rv;
}
#else
/* XXX This version of copyoutstr(9) has never been enabled so far. */
int
copyoutstr(const void *ksaddr, void *udaddr, size_t len, size_t *lenp)
{
        struct pcb * const pcb = lwp_getpcb(curlwp);
        struct faultbuf env;

        if (__predict_false(len == 0)) {
                if (lenp)
                        *lenp = 0;
                return 0;
        }

        if (setfault(&env)) {
                pcb->pcb_onfault = NULL;
                if (lenp)
                        *lenp = 0;
                return EFAULT;
        }

        const register_t ds_msr = mfmsr() | PSL_DS;
        const uint8_t *ksaddr8 = ksaddr;
        size_t copylen = 0;

        uint32_t *udaddr32 = (void *)((uintptr_t)udaddr & ~3);

        size_t boff = (uintptr_t)udaddr & 3;
        bool done = false;
        size_t wlen = 0;
        size_t data = 0;

        /*
         * If the destination buffer doesn't start on a 32-bit boundary
         * try to partially fill in the first word.  If we succeed we can
         * finish writing it while preserving the bytes on front.
         */
        if (boff > 0) {
                KASSERT(len > 0);
                do {
                        data = (data << 8) | *ksaddr8++;
                        wlen++;
                        done = ((uint8_t)data == 0 || len == wlen);
                } while (!done && boff + wlen < 4);
                KASSERT(wlen > 0);
                data <<= 8 * boff;
                if (!done || boff + wlen == 4) {
                        uint32_t mask = 0xffffffff << (8 * boff);
                        copyout_le32_with_mask(udaddr32++, data, mask, ds_msr);
                        boff = 0;
                        copylen = wlen;
                        wlen = 0;
                        data = 0;
                }
        }

        /*
         * Now we get to the heart of the routine.  Build up complete words
         * if possible.  When we have one, write it to the user's address
         * space and go for the next.  If we ran out of space or we found the
         * end of the string, stop building.  If we managed to build a complete
         * word, just write it and be happy.  Otherwise we have to deal with
         * the trailing bytes.
         */
        KASSERT(done || boff == 0);
        KASSERT(done || copylen < len);
        while (!done) {
                KASSERT(wlen == 0);
                KASSERT(copylen < len);
                do {
                        data = (data << 8) | *ksaddr8++;
                        wlen++;
                        done = ((uint8_t)data == 0 || copylen + wlen == len);
                } while (!done && wlen < 4);
                KASSERT(done || wlen == 4);
                if (__predict_true(wlen == 4)) {
                        copyout_le32(udaddr32++, data, ds_msr);
                        data = 0;
                        copylen += wlen;
                        wlen = 0;
                        KASSERT(copylen < len || done);
                }
        }
        KASSERT(wlen < 3);
        if (wlen) {
                /*
                 * Remember even though we are running big-endian we are using
                 * byte reversed load/stores so we need to deal with things as
                 * little endian.
                 *
                 * wlen=1 boff=0:
                 * (~(~0 <<  8) <<  0) -> (~(0xffffff00) <<  0) -> 0x000000ff
                 * wlen=1 boff=1:
                 * (~(~0 <<  8) <<  8) -> (~(0xffffff00) <<  8) -> 0x0000ff00
                 * wlen=1 boff=2:
                 * (~(~0 <<  8) << 16) -> (~(0xffffff00) << 16) -> 0x00ff0000
                 * wlen=1 boff=3:
                 * (~(~0 <<  8) << 24) -> (~(0xffffff00) << 24) -> 0xff000000
                 * wlen=2 boff=0:
                 * (~(~0 << 16) <<  0) -> (~(0xffff0000) <<  0) -> 0x0000ffff
                 * wlen=2 boff=1:
                 * (~(~0 << 16) <<  8) -> (~(0xffff0000) <<  8) -> 0x00ffff00
                 * wlen=2 boff=2:
                 * (~(~0 << 16) << 16) -> (~(0xffff0000) << 16) -> 0xffff0000
                 * wlen=3 boff=0:
                 * (~(~0 << 24) <<  0) -> (~(0xff000000) <<  0) -> 0x00ffffff
                 * wlen=3 boff=1:
                 * (~(~0 << 24) <<  8) -> (~(0xff000000) <<  8) -> 0xffffff00
                 */
                KASSERT(boff + wlen <= 4);
                uint32_t mask = (~(~0 << (8 * wlen))) << (8 * boff);
                KASSERT(mask != 0xffffffff);
                copyout_le32_with_mask(udaddr32, data, mask, ds_msr);
                copylen += wlen;
        }

        pcb->pcb_onfault = NULL;
        if (lenp)
                *lenp = copylen;
        return 0;
}
#endif