common/os/subr.c

	subr.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * 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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */


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

#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/param.h>
#include <sys/vmparam.h>
#include <sys/systm.h>
#include <sys/cred.h>
#include <sys/user.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/tuneable.h>
#include <sys/cpuvar.h>
#include <sys/archsystm.h>
#include <sys/vmem.h>
#include <vm/seg_kmem.h>
#include <sys/errno.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/atomic.h>
#include <sys/model.h>
#include <sys/kmem.h>
#include <sys/memlist.h>
#include <sys/autoconf.h>
#include <sys/ontrap.h>
#include <sys/utsname.h>
#include <sys/zone.h>

#ifdef __sparc
#include <sys/membar.h>
#endif

/*
 * Routine which sets a user error; placed in
 * illegal entries in the bdevsw and cdevsw tables.
 */

int
nodev()
{
    return (curthread->t_lwp ?
        ttolwp(curthread)->lwp_error = ENXIO : ENXIO);
}

/*
 * Null routine; placed in insignificant entries
 * in the bdevsw and cdevsw tables.
 */

int
nulldev()
{
    return (0);
}

static kmutex_t udevlock;

/*
 * Generate an unused major device number.
 */
major_t
getudev()
{
    static major_t next = 0;
    major_t ret;

    /*
     * Ensure that we start allocating major numbers above the 'devcnt'
     * count.  The only limit we place on the number is that it should be a
     * legal 32-bit SVR4 major number and be greater than or equal to devcnt
     * in the current system).
     */
    mutex_enter(&udevlock);
    if (next == 0)
        next = devcnt;
    if (next <= L_MAXMAJ32 && next >= devcnt)
        ret = next++;
    else {
        /*
         * If we fail to allocate a major number because devcnt has
         * reached L_MAXMAJ32, we may be the victim of a sparsely
         * populated devnames array.  We scan the array backwards
         * looking for an empty slot;  if we find one, mark it as
         * DN_GETUDEV so it doesn't get taken by subsequent consumers
         * users of the devnames array, and issue a warning.
         * It is vital for this routine to take drastic measures to
         * succeed, since the kernel really needs it to boot.
         */
        int i;
        for (i = devcnt - 1; i >= 0; i--) {
            LOCK_DEV_OPS(&devnamesp[i].dn_lock);
            if (devnamesp[i].dn_name == NULL &&
                ((devnamesp[i].dn_flags & DN_TAKEN_GETUDEV) == 0))
                break;
            UNLOCK_DEV_OPS(&devnamesp[i].dn_lock);
        }
        if (i != -1) {
            cmn_err(CE_WARN, "Reusing device major number %d.", i);
            ASSERT(i >= 0 && i < devcnt);
            devnamesp[i].dn_flags |= DN_TAKEN_GETUDEV;
            UNLOCK_DEV_OPS(&devnamesp[i].dn_lock);
            ret = (major_t)i;
        } else {
            ret = (major_t)-1;
        }
    }
    mutex_exit(&udevlock);
    return (ret);
}


/*
 * Compress 'long' device number encoding to 32-bit device number
 * encoding.  If it won't fit, we return failure, but set the
 * device number to 32-bit NODEV for the sake of our callers.
 */
int
cmpldev(dev32_t *dst, dev_t dev)
{
#if defined(_LP64)
    if (dev == NODEV) {
        *dst = NODEV32;
    } else {
        major_t major = dev >> L_BITSMINOR;
        minor_t minor = dev & L_MAXMIN;

        if (major > L_MAXMAJ32 || minor > L_MAXMIN32) {
            *dst = NODEV32;
            return (0);
        }

        *dst = (dev32_t)((major << L_BITSMINOR32) | minor);
    }
#else
    *dst = (dev32_t)dev;
#endif
    return (1);
}

/*
 * Expand 32-bit dev_t's to long dev_t's.  Expansion always "fits"
 * into the return type, but we're careful to expand NODEV explicitly.
 */
dev_t
expldev(dev32_t dev32)
{
#ifdef _LP64
    if (dev32 == NODEV32)
        return (NODEV);
    return (makedevice((dev32 >> L_BITSMINOR32) & L_MAXMAJ32,
        dev32 & L_MAXMIN32));
#else
    return ((dev_t)dev32);
#endif
}

#ifndef _LP64
/*
 * Keep these entry points for 32-bit systems but enforce the use
 * of MIN/MAX macros on 64-bit systems.  The DDI header files already
 * define min/max as macros so drivers shouldn't need these functions.
 */

int
min(int a, int b)
{
    return (a < b ? a : b);
}

int
max(int a, int b)
{
    return (a > b ? a : b);
}

uint_t
umin(uint_t a, uint_t b)
{
    return (a < b ? a : b);
}

uint_t
umax(uint_t a, uint_t b)
{
    return (a > b ? a : b);
}

#endif /* !_LP64 */

/*
 * Return bit position of least significant bit set in mask,
 * starting numbering from 1.
 */
int
ffs(long mask)
{
    int i;

    if (mask == 0)
        return (0);
    for (i = 1; i <= NBBY * sizeof (mask); i++) {
        if (mask & 1)
            return (i);
        mask >>= 1;
    }
    return (0);
}

/*
 * Parse suboptions from a string.
 * Same as getsubopt(3C).
 */
int
getsubopt(char **optionsp, char * const *tokens, char **valuep)
{
    char *s = *optionsp, *p;
    int i;
    size_t optlen;

    *valuep = NULL;
    if (*s == '\0')
        return (-1);
    p = strchr(s, ',');     /* find next option */
    if (p == NULL) {
        p = s + strlen(s);
    } else {
        *p++ = '\0';        /* mark end and point to next */
    }
    *optionsp = p;          /* point to next option */
    p = strchr(s, '=');     /* find value */
    if (p == NULL) {
        optlen = strlen(s);
        *valuep = NULL;
    } else {
        optlen = p - s;
        *valuep = ++p;
    }
    for (i = 0; tokens[i] != NULL; i++) {
        if ((optlen == strlen(tokens[i])) &&
            (strncmp(s, tokens[i], optlen) == 0))
            return (i);
    }
    /* no match, point value at option and return error */
    *valuep = s;
    return (-1);
}

/*
 * Append the suboption string 'opt' starting at the position 'str'
 * within the buffer defined by 'buf' and 'len'. If 'buf' is not null,
 * a comma is appended first.
 * Return a pointer to the end of the resulting string (the null byte).
 * Return NULL if there isn't enough space left to append 'opt'.
 */
char *
append_subopt(const char *buf, size_t len, char *str, const char *opt)
{
    size_t l = strlen(opt);

    /*
     * Include a ',' if this is not the first option.
     * Include space for the null byte.
     */
    if (strlen(buf) + (buf[0] != '\0') + l + 1 > len)
        return (NULL);

    if (buf[0] != '\0')
        *str++ = ',';
    (void) strcpy(str, opt);
    return (str + l);
}

/*
 * Tables to convert a single byte to/from binary-coded decimal (BCD).
 */
uchar_t byte_to_bcd[256] = {
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
    0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29,
    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
    0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
    0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
    0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
    0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
    0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
};

uchar_t bcd_to_byte[256] = {        /* CSTYLED */
     0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  0,  0,  0,  0,  0,  0,
    10, 11, 12, 13, 14, 15, 16, 17, 18, 19,  0,  0,  0,  0,  0,  0,
    20, 21, 22, 23, 24, 25, 26, 27, 28, 29,  0,  0,  0,  0,  0,  0,
    30, 31, 32, 33, 34, 35, 36, 37, 38, 39,  0,  0,  0,  0,  0,  0,
    40, 41, 42, 43, 44, 45, 46, 47, 48, 49,  0,  0,  0,  0,  0,  0,
    50, 51, 52, 53, 54, 55, 56, 57, 58, 59,  0,  0,  0,  0,  0,  0,
    60, 61, 62, 63, 64, 65, 66, 67, 68, 69,  0,  0,  0,  0,  0,  0,
    70, 71, 72, 73, 74, 75, 76, 77, 78, 79,  0,  0,  0,  0,  0,  0,
    80, 81, 82, 83, 84, 85, 86, 87, 88, 89,  0,  0,  0,  0,  0,  0,
    90, 91, 92, 93, 94, 95, 96, 97, 98, 99,
};

/*
 * Hot-patch a single instruction in the kernel's text.
 * If you want to patch multiple instructions you must
 * arrange to do it so that all intermediate stages are
 * sane -- we don't stop other cpus while doing this.
 * Size must be 1, 2, or 4 bytes with iaddr aligned accordingly.
 */
void
hot_patch_kernel_text(caddr_t iaddr, uint32_t new_instr, uint_t size)
{
    caddr_t vaddr;
    page_t **ppp;
    uintptr_t off = (uintptr_t)iaddr & PAGEOFFSET;

    vaddr = vmem_alloc(heap_arena, PAGESIZE, VM_SLEEP);

    (void) as_pagelock(&kas, &ppp, iaddr - off, PAGESIZE, S_WRITE);

    hat_devload(kas.a_hat, vaddr, PAGESIZE,
        hat_getpfnum(kas.a_hat, iaddr - off),
        PROT_READ | PROT_WRITE, HAT_LOAD_LOCK | HAT_LOAD_NOCONSIST);

    switch (size) {
    case 1:
        *(uint8_t *)(vaddr + off) = new_instr;
        break;
    case 2:
        *(uint16_t *)(vaddr + off) = new_instr;
        break;
    case 4:
        *(uint32_t *)(vaddr + off) = new_instr;
        break;
    default:
        panic("illegal hot-patch");
    }

    membar_enter();
    sync_icache(vaddr + off, size);
    sync_icache(iaddr, size);
    as_pageunlock(&kas, ppp, iaddr - off, PAGESIZE, S_WRITE);
    hat_unload(kas.a_hat, vaddr, PAGESIZE, HAT_UNLOAD_UNLOCK);
    vmem_free(heap_arena, vaddr, PAGESIZE);
}

/*
 * Routine to report an attempt to execute non-executable data.  If the
 * address executed lies in the stack, explicitly say so.
 */
void
report_stack_exec(proc_t *p, caddr_t addr)
{
    if (!noexec_user_stack_log)
        return;

    if (addr < p->p_usrstack && addr >= (p->p_usrstack - p->p_stksize)) {
        cmn_err(CE_NOTE, "%s[%d] attempt to execute code "
            "on stack by uid %d", p->p_user.u_comm,
            p->p_pid, crgetruid(p->p_cred));
    } else {
        cmn_err(CE_NOTE, "%s[%d] attempt to execute non-executable "
            "data at 0x%p by uid %d", p->p_user.u_comm,
            p->p_pid, (void *) addr, crgetruid(p->p_cred));
    }

    delay(hz / 50);
}

/*
 * Determine whether the address range [addr, addr + len) is in memlist mp.
 */
int
address_in_memlist(struct memlist *mp, uint64_t addr, size_t len)
{
    while (mp != 0)  {
        if ((addr >= mp->address) &&
            (addr + len <= mp->address + mp->size))
            return (1);  /* TRUE */
        mp = mp->next;
    }
    return (0); /* FALSE */
}

/*
 * Pop the topmost element from the t_ontrap stack, removing the current set of
 * on_trap() protections.  Refer to <sys/ontrap.h> for more info.  If the
 * stack is already empty, no_trap() just returns.
 */
void
no_trap(void)
{
    if (curthread->t_ontrap != NULL) {
#ifdef __sparc
        membar_sync(); /* deferred error barrier (see sparcv9_subr.s) */
#endif
        curthread->t_ontrap = curthread->t_ontrap->ot_prev;
    }
}

/*
 * Return utsname.nodename outside a zone, or the zone name within.
 */
char *
uts_nodename(void)
{
    if (curproc == NULL)
        return (utsname.nodename);
    return (curproc->p_zone->zone_nodename);
}