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zfs/module/spl/spl-generic.c

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/*****************************************************************************\
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://github.com/behlendorf/spl/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
*****************************************************************************
* Solaris Porting Layer (SPL) Generic Implementation.
\*****************************************************************************/
#include <sys/sysmacros.h>
#include <sys/systeminfo.h>
#include <sys/vmsystm.h>
#include <sys/kobj.h>
#include <sys/kmem.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>
#include <sys/taskq.h>
#include <sys/tsd.h>
#include <sys/zmod.h>
#include <sys/debug.h>
#include <sys/proc.h>
#include <sys/kstat.h>
#include <sys/utsname.h>
#include <sys/file.h>
#include <linux/kmod.h>
#include <linux/proc_compat.h>
#include <spl-debug.h>
#ifdef SS_DEBUG_SUBSYS
#undef SS_DEBUG_SUBSYS
#endif
#define SS_DEBUG_SUBSYS SS_GENERIC
char spl_version[32] = "SPL v" SPL_META_VERSION "-" SPL_META_RELEASE;
EXPORT_SYMBOL(spl_version);
unsigned long spl_hostid = HW_INVALID_HOSTID;
EXPORT_SYMBOL(spl_hostid);
module_param(spl_hostid, ulong, 0644);
MODULE_PARM_DESC(spl_hostid, "The system hostid.");
char hw_serial[HW_HOSTID_LEN] = "<none>";
EXPORT_SYMBOL(hw_serial);
proc_t p0 = { 0 };
EXPORT_SYMBOL(p0);
#ifndef HAVE_KALLSYMS_LOOKUP_NAME
DECLARE_WAIT_QUEUE_HEAD(spl_kallsyms_lookup_name_waitq);
kallsyms_lookup_name_t spl_kallsyms_lookup_name_fn = SYMBOL_POISON;
#endif
int
highbit(unsigned long i)
{
register int h = 1;
SENTRY;
if (i == 0)
SRETURN(0);
#if BITS_PER_LONG == 64
if (i & 0xffffffff00000000ul) {
h += 32; i >>= 32;
}
#endif
if (i & 0xffff0000) {
h += 16; i >>= 16;
}
if (i & 0xff00) {
h += 8; i >>= 8;
}
if (i & 0xf0) {
h += 4; i >>= 4;
}
if (i & 0xc) {
h += 2; i >>= 2;
}
if (i & 0x2) {
h += 1;
}
SRETURN(h);
}
EXPORT_SYMBOL(highbit);
#if BITS_PER_LONG == 32
/*
* Support 64/64 => 64 division on a 32-bit platform. While the kernel
* provides a div64_u64() function for this we do not use it because the
* implementation is flawed. There are cases which return incorrect
* results as late as linux-2.6.35. Until this is fixed upstream the
* spl must provide its own implementation.
*
* This implementation is a slightly modified version of the algorithm
* proposed by the book 'Hacker's Delight'. The original source can be
* found here and is available for use without restriction.
*
* http://www.hackersdelight.org/HDcode/newCode/divDouble.c
*/
/*
* Calculate number of leading of zeros for a 64-bit value.
*/
static int
nlz64(uint64_t x) {
register int n = 0;
if (x == 0)
return 64;
if (x <= 0x00000000FFFFFFFFULL) {n = n + 32; x = x << 32;}
if (x <= 0x0000FFFFFFFFFFFFULL) {n = n + 16; x = x << 16;}
if (x <= 0x00FFFFFFFFFFFFFFULL) {n = n + 8; x = x << 8;}
if (x <= 0x0FFFFFFFFFFFFFFFULL) {n = n + 4; x = x << 4;}
if (x <= 0x3FFFFFFFFFFFFFFFULL) {n = n + 2; x = x << 2;}
if (x <= 0x7FFFFFFFFFFFFFFFULL) {n = n + 1;}
return n;
}
/*
* Newer kernels have a div_u64() function but we define our own
* to simplify portibility between kernel versions.
*/
static inline uint64_t
__div_u64(uint64_t u, uint32_t v)
{
(void) do_div(u, v);
return u;
}
/*
* Implementation of 64-bit unsigned division for 32-bit machines.
*
* First the procedure takes care of the case in which the divisor is a
* 32-bit quantity. There are two subcases: (1) If the left half of the
* dividend is less than the divisor, one execution of do_div() is all that
* is required (overflow is not possible). (2) Otherwise it does two
* divisions, using the grade school method.
*/
uint64_t
__udivdi3(uint64_t u, uint64_t v)
{
uint64_t u0, u1, v1, q0, q1, k;
int n;
if (v >> 32 == 0) { // If v < 2**32:
if (u >> 32 < v) { // If u/v cannot overflow,
return __div_u64(u, v); // just do one division.
} else { // If u/v would overflow:
u1 = u >> 32; // Break u into two halves.
u0 = u & 0xFFFFFFFF;
q1 = __div_u64(u1, v); // First quotient digit.
k = u1 - q1 * v; // First remainder, < v.
u0 += (k << 32);
q0 = __div_u64(u0, v); // Seconds quotient digit.
return (q1 << 32) + q0;
}
} else { // If v >= 2**32:
n = nlz64(v); // 0 <= n <= 31.
v1 = (v << n) >> 32; // Normalize divisor, MSB is 1.
u1 = u >> 1; // To ensure no overflow.
q1 = __div_u64(u1, v1); // Get quotient from
q0 = (q1 << n) >> 31; // Undo normalization and
// division of u by 2.
if (q0 != 0) // Make q0 correct or
q0 = q0 - 1; // too small by 1.
if ((u - q0 * v) >= v)
q0 = q0 + 1; // Now q0 is correct.
return q0;
}
}
EXPORT_SYMBOL(__udivdi3);
/*
* Implementation of 64-bit signed division for 32-bit machines.
*/
int64_t
__divdi3(int64_t u, int64_t v)
{
int64_t q, t;
q = __udivdi3(abs64(u), abs64(v));
t = (u ^ v) >> 63; // If u, v have different
return (q ^ t) - t; // signs, negate q.
}
EXPORT_SYMBOL(__divdi3);
/*
* Implementation of 64-bit unsigned modulo for 32-bit machines.
*/
uint64_t
__umoddi3(uint64_t dividend, uint64_t divisor)
{
return (dividend - (divisor * __udivdi3(dividend, divisor)));
}
EXPORT_SYMBOL(__umoddi3);
#if defined(__arm) || defined(__arm__)
/*
* Implementation of 64-bit (un)signed division for 32-bit arm machines.
*
* Run-time ABI for the ARM Architecture (page 20). A pair of (unsigned)
* long longs is returned in {{r0, r1}, {r2,r3}}, the quotient in {r0, r1},
* and the remainder in {r2, r3}. The return type is specifically left
* set to 'void' to ensure the compiler does not overwrite these registers
* during the return. All results are in registers as per ABI
*/
void
__aeabi_uldivmod(uint64_t u, uint64_t v)
{
uint64_t res;
uint64_t mod;
res = __udivdi3(u, v);
mod = __umoddi3(u, v);
{
register uint32_t r0 asm("r0") = (res & 0xFFFFFFFF);
register uint32_t r1 asm("r1") = (res >> 32);
register uint32_t r2 asm("r2") = (mod & 0xFFFFFFFF);
register uint32_t r3 asm("r3") = (mod >> 32);
asm volatile(""
: "+r"(r0), "+r"(r1), "+r"(r2),"+r"(r3) /* output */
: "r"(r0), "r"(r1), "r"(r2), "r"(r3)); /* input */
return; /* r0; */
}
}
EXPORT_SYMBOL(__aeabi_uldivmod);
void
__aeabi_ldivmod(int64_t u, int64_t v)
{
int64_t res;
uint64_t mod;
res = __divdi3(u, v);
mod = __umoddi3(u, v);
{
register uint32_t r0 asm("r0") = (res & 0xFFFFFFFF);
register uint32_t r1 asm("r1") = (res >> 32);
register uint32_t r2 asm("r2") = (mod & 0xFFFFFFFF);
register uint32_t r3 asm("r3") = (mod >> 32);
asm volatile(""
: "+r"(r0), "+r"(r1), "+r"(r2),"+r"(r3) /* output */
: "r"(r0), "r"(r1), "r"(r2), "r"(r3)); /* input */
return; /* r0; */
}
}
EXPORT_SYMBOL(__aeabi_ldivmod);
#endif /* __arm || __arm__ */
#endif /* BITS_PER_LONG */
/* NOTE: The strtoxx behavior is solely based on my reading of the Solaris
* ddi_strtol(9F) man page. I have not verified the behavior of these
* functions against their Solaris counterparts. It is possible that I
* may have misinterpreted the man page or the man page is incorrect.
*/
int ddi_strtoul(const char *, char **, int, unsigned long *);
int ddi_strtol(const char *, char **, int, long *);
int ddi_strtoull(const char *, char **, int, unsigned long long *);
int ddi_strtoll(const char *, char **, int, long long *);
#define define_ddi_strtoux(type, valtype) \
int ddi_strtou##type(const char *str, char **endptr, \
int base, valtype *result) \
{ \
valtype last_value, value = 0; \
char *ptr = (char *)str; \
int flag = 1, digit; \
\
if (strlen(ptr) == 0) \
return EINVAL; \
\
/* Auto-detect base based on prefix */ \
if (!base) { \
if (str[0] == '0') { \
if (tolower(str[1])=='x' && isxdigit(str[2])) { \
base = 16; /* hex */ \
ptr += 2; \
} else if (str[1] >= '0' && str[1] < 8) { \
base = 8; /* octal */ \
ptr += 1; \
} else { \
return EINVAL; \
} \
} else { \
base = 10; /* decimal */ \
} \
} \
\
while (1) { \
if (isdigit(*ptr)) \
digit = *ptr - '0'; \
else if (isalpha(*ptr)) \
digit = tolower(*ptr) - 'a' + 10; \
else \
break; \
\
if (digit >= base) \
break; \
\
last_value = value; \
value = value * base + digit; \
if (last_value > value) /* Overflow */ \
return ERANGE; \
\
flag = 1; \
ptr++; \
} \
\
if (flag) \
*result = value; \
\
if (endptr) \
*endptr = (char *)(flag ? ptr : str); \
\
return 0; \
} \
#define define_ddi_strtox(type, valtype) \
int ddi_strto##type(const char *str, char **endptr, \
int base, valtype *result) \
{ \
int rc; \
\
if (*str == '-') { \
rc = ddi_strtou##type(str + 1, endptr, base, result); \
if (!rc) { \
if (*endptr == str + 1) \
*endptr = (char *)str; \
else \
*result = -*result; \
} \
} else { \
rc = ddi_strtou##type(str, endptr, base, result); \
} \
\
return rc; \
}
define_ddi_strtoux(l, unsigned long)
define_ddi_strtox(l, long)
define_ddi_strtoux(ll, unsigned long long)
define_ddi_strtox(ll, long long)
EXPORT_SYMBOL(ddi_strtoul);
EXPORT_SYMBOL(ddi_strtol);
EXPORT_SYMBOL(ddi_strtoll);
EXPORT_SYMBOL(ddi_strtoull);
int
ddi_copyin(const void *from, void *to, size_t len, int flags)
{
/* Fake ioctl() issued by kernel, 'from' is a kernel address */
if (flags & FKIOCTL) {
memcpy(to, from, len);
return 0;
}
return copyin(from, to, len);
}
EXPORT_SYMBOL(ddi_copyin);
int
ddi_copyout(const void *from, void *to, size_t len, int flags)
{
/* Fake ioctl() issued by kernel, 'from' is a kernel address */
if (flags & FKIOCTL) {
memcpy(to, from, len);
return 0;
}
return copyout(from, to, len);
}
EXPORT_SYMBOL(ddi_copyout);
#ifndef HAVE_PUT_TASK_STRUCT
/*
* This is only a stub function which should never be used. The SPL should
* never be putting away the last reference on a task structure so this will
* not be called. However, we still need to define it so the module does not
* have undefined symbol at load time. That all said if this impossible
* thing does somehow happen PANIC immediately so we know about it.
*/
void
__put_task_struct(struct task_struct *t)
{
PANIC("Unexpectly put last reference on task %d\n", (int)t->pid);
}
EXPORT_SYMBOL(__put_task_struct);
#endif /* HAVE_PUT_TASK_STRUCT */
struct new_utsname *__utsname(void)
{
#ifdef HAVE_INIT_UTSNAME
return init_utsname();
#else
return &system_utsname;
#endif
}
EXPORT_SYMBOL(__utsname);
/*
* Read the unique system identifier from the /etc/hostid file.
*
* The behavior of /usr/bin/hostid on Linux systems with the
* regular eglibc and coreutils is:
*
* 1. Generate the value if the /etc/hostid file does not exist
* or if the /etc/hostid file is less than four bytes in size.
*
* 2. If the /etc/hostid file is at least 4 bytes, then return
* the first four bytes [0..3] in native endian order.
*
* 3. Always ignore bytes [4..] if they exist in the file.
*
* Only the first four bytes are significant, even on systems that
* have a 64-bit word size.
*
* See:
*
* eglibc: sysdeps/unix/sysv/linux/gethostid.c
* coreutils: src/hostid.c
*
* Notes:
*
* The /etc/hostid file on Solaris is a text file that often reads:
*
* # DO NOT EDIT
* "0123456789"
*
* Directly copying this file to Linux results in a constant
* hostid of 4f442023 because the default comment constitutes
* the first four bytes of the file.
*
*/
char *spl_hostid_path = HW_HOSTID_PATH;
module_param(spl_hostid_path, charp, 0444);
MODULE_PARM_DESC(spl_hostid_path, "The system hostid file (/etc/hostid)");
static int
hostid_read(void)
{
int result;
uint64_t size;
struct _buf *file;
unsigned long hostid = 0;
file = kobj_open_file(spl_hostid_path);
if (file == (struct _buf *)-1)
return -1;
result = kobj_get_filesize(file, &size);
if (result != 0) {
printk(KERN_WARNING
"SPL: kobj_get_filesize returned %i on %s\n",
result, spl_hostid_path);
kobj_close_file(file);
return -2;
}
if (size < sizeof(HW_HOSTID_MASK)) {
printk(KERN_WARNING
"SPL: Ignoring the %s file because it is %llu bytes; "
"expecting %lu bytes instead.\n", spl_hostid_path,
size, (unsigned long)sizeof(HW_HOSTID_MASK));
kobj_close_file(file);
return -3;
}
/* Read directly into the variable like eglibc does. */
/* Short reads are okay; native behavior is preserved. */
result = kobj_read_file(file, (char *)&hostid, sizeof(hostid), 0);
if (result < 0) {
printk(KERN_WARNING
"SPL: kobj_read_file returned %i on %s\n",
result, spl_hostid_path);
kobj_close_file(file);
return -4;
}
/* Mask down to 32 bits like coreutils does. */
spl_hostid = hostid & HW_HOSTID_MASK;
kobj_close_file(file);
return 0;
}
#define GET_HOSTID_CMD \
"exec 0</dev/null " \
" 1>/proc/sys/kernel/spl/hostid " \
" 2>/dev/null; " \
"hostid"
static int
hostid_exec(void)
{
char *argv[] = { "/bin/sh",
"-c",
GET_HOSTID_CMD,
NULL };
char *envp[] = { "HOME=/",
"TERM=linux",
"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
NULL };
int rc;
/* Doing address resolution in the kernel is tricky and just
* not a good idea in general. So to set the proper 'hw_serial'
* use the usermodehelper support to ask '/bin/sh' to run
* '/usr/bin/hostid' and redirect the result to /proc/sys/spl/hostid
* for us to use. It's a horrific solution but it will do for now.
*/
rc = call_usermodehelper(argv[0], argv, envp, 1);
if (rc)
printk("SPL: Failed user helper '%s %s %s', rc = %d\n",
argv[0], argv[1], argv[2], rc);
return rc;
}
uint32_t
zone_get_hostid(void *zone)
{
static int first = 1;
unsigned long hostid;
int rc;
/* Only the global zone is supported */
ASSERT(zone == NULL);
if (first) {
first = 0;
/*
* Get the hostid if it was not passed as a module parameter.
* Try reading the /etc/hostid file directly, and then fall
* back to calling the /usr/bin/hostid utility.
*/
if ((spl_hostid == HW_INVALID_HOSTID) &&
(rc = hostid_read()) && (rc = hostid_exec()))
return HW_INVALID_HOSTID;
printk(KERN_NOTICE "SPL: using hostid 0x%08x\n",
(unsigned int) spl_hostid);
}
if (ddi_strtoul(hw_serial, NULL, HW_HOSTID_LEN-1, &hostid) != 0)
return HW_INVALID_HOSTID;
return (uint32_t)hostid;
}
EXPORT_SYMBOL(zone_get_hostid);
#ifndef HAVE_KALLSYMS_LOOKUP_NAME
/*
* The kallsyms_lookup_name() kernel function is not an exported symbol in
* Linux 2.6.19 through 2.6.32 inclusive.
*
* This function replaces the functionality by performing an upcall to user
* space where /proc/kallsyms is consulted for the requested address.
*
*/
#define GET_KALLSYMS_ADDR_CMD \
"exec 0</dev/null " \
" 1>/proc/sys/kernel/spl/kallsyms_lookup_name " \
" 2>/dev/null; " \
"awk '{ if ( $3 == \"kallsyms_lookup_name\" ) { print $1 } }' " \
" /proc/kallsyms "
static int
set_kallsyms_lookup_name(void)
{
char *argv[] = { "/bin/sh",
"-c",
GET_KALLSYMS_ADDR_CMD,
NULL };
char *envp[] = { "HOME=/",
"TERM=linux",
"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
NULL };
int rc;
rc = call_usermodehelper(argv[0], argv, envp, 1);
/*
* Due to I/O buffering the helper may return successfully before
* the proc handler has a chance to execute. To catch this case
* wait up to 1 second to verify spl_kallsyms_lookup_name_fn was
* updated to a non SYMBOL_POISON value.
*/
if (rc == 0) {
rc = wait_event_timeout(spl_kallsyms_lookup_name_waitq,
spl_kallsyms_lookup_name_fn != SYMBOL_POISON, HZ);
if (rc == 0)
rc = -ETIMEDOUT;
else if (spl_kallsyms_lookup_name_fn == SYMBOL_POISON)
rc = -EFAULT;
else
rc = 0;
}
if (rc)
printk("SPL: Failed user helper '%s %s %s', rc = %d\n",
argv[0], argv[1], argv[2], rc);
return rc;
}
#endif
static int
__init spl_init(void)
{
int rc = 0;
if ((rc = spl_debug_init()))
return rc;
if ((rc = spl_kmem_init()))
SGOTO(out1, rc);
if ((rc = spl_mutex_init()))
SGOTO(out2, rc);
if ((rc = spl_rw_init()))
SGOTO(out3, rc);
if ((rc = spl_taskq_init()))
SGOTO(out4, rc);
if ((rc = spl_vn_init()))
SGOTO(out5, rc);
if ((rc = spl_proc_init()))
SGOTO(out6, rc);
if ((rc = spl_kstat_init()))
SGOTO(out7, rc);
if ((rc = spl_tsd_init()))
SGOTO(out8, rc);
if ((rc = spl_zlib_init()))
SGOTO(out9, rc);
#ifndef HAVE_KALLSYMS_LOOKUP_NAME
if ((rc = set_kallsyms_lookup_name()))
SGOTO(out10, rc = -EADDRNOTAVAIL);
#endif /* HAVE_KALLSYMS_LOOKUP_NAME */
if ((rc = spl_kmem_init_kallsyms_lookup()))
SGOTO(out10, rc);
if ((rc = spl_vn_init_kallsyms_lookup()))
SGOTO(out10, rc);
printk(KERN_NOTICE "SPL: Loaded module v%s-%s%s\n", SPL_META_VERSION,
SPL_META_RELEASE, SPL_DEBUG_STR);
SRETURN(rc);
out10:
spl_zlib_fini();
out9:
spl_tsd_fini();
out8:
spl_kstat_fini();
out7:
spl_proc_fini();
out6:
spl_vn_fini();
out5:
spl_taskq_fini();
out4:
spl_rw_fini();
out3:
spl_mutex_fini();
out2:
spl_kmem_fini();
out1:
spl_debug_fini();
printk(KERN_NOTICE "SPL: Failed to Load Solaris Porting Layer "
"v%s-%s%s, rc = %d\n", SPL_META_VERSION, SPL_META_RELEASE,
SPL_DEBUG_STR, rc);
return rc;
}
static void
spl_fini(void)
{
SENTRY;
printk(KERN_NOTICE "SPL: Unloaded module v%s-%s%s\n",
SPL_META_VERSION, SPL_META_RELEASE, SPL_DEBUG_STR);
spl_zlib_fini();
spl_tsd_fini();
spl_kstat_fini();
spl_proc_fini();
spl_vn_fini();
spl_taskq_fini();
spl_rw_fini();
spl_mutex_fini();
spl_kmem_fini();
spl_debug_fini();
}
/* Called when a dependent module is loaded */
void
spl_setup(void)
{
int rc;
/*
* At module load time the pwd is set to '/' on a Solaris system.
* On a Linux system will be set to whatever directory the caller
* was in when executing insmod/modprobe.
*/
rc = vn_set_pwd("/");
if (rc)
printk("SPL: Warning unable to set pwd to '/': %d\n", rc);
}
EXPORT_SYMBOL(spl_setup);
/* Called when a dependent module is unloaded */
void
spl_cleanup(void)
{
}
EXPORT_SYMBOL(spl_cleanup);
module_init(spl_init);
module_exit(spl_fini);
MODULE_AUTHOR("Lawrence Livermore National Labs");
MODULE_DESCRIPTION("Solaris Porting Layer");
MODULE_LICENSE("GPL");
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