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1 /*****************************************************************************\
2 * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
3 * Copyright (C) 2007 The Regents of the University of California.
4 * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
5 * Written by Brian Behlendorf <behlendorf1@llnl.gov>.
8 * This file is part of the SPL, Solaris Porting Layer.
9 * For details, see <http://zfsonlinux.org/>.
11 * The SPL is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
16 * The SPL is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
21 * You should have received a copy of the GNU General Public License along
22 * with the SPL. If not, see <http://www.gnu.org/licenses/>.
23 *****************************************************************************
24 * Solaris Porting Layer (SPL) Generic Implementation.
25 \*****************************************************************************/
27 #include <sys/sysmacros.h>
28 #include <sys/systeminfo.h>
29 #include <sys/vmsystm.h>
32 #include <sys/kmem_cache.h>
34 #include <sys/mutex.h>
35 #include <sys/rwlock.h>
36 #include <sys/taskq.h>
39 #include <sys/debug.h>
41 #include <sys/kstat.h>
43 #include <linux/ctype.h>
45 #include <sys/random.h>
46 #include <linux/kmod.h>
47 #include <linux/math64_compat.h>
48 #include <linux/proc_compat.h>
50 char spl_version
[32] = "SPL v" SPL_META_VERSION
"-" SPL_META_RELEASE
;
51 EXPORT_SYMBOL(spl_version
);
53 unsigned long spl_hostid
= 0;
54 EXPORT_SYMBOL(spl_hostid
);
55 module_param(spl_hostid
, ulong
, 0644);
56 MODULE_PARM_DESC(spl_hostid
, "The system hostid.");
62 * Xorshift Pseudo Random Number Generator based on work by Sebastiano Vigna
64 * "Further scramblings of Marsaglia's xorshift generators"
65 * http://vigna.di.unimi.it/ftp/papers/xorshiftplus.pdf
67 * random_get_pseudo_bytes() is an API function on Illumos whose sole purpose
68 * is to provide bytes containing random numbers. It is mapped to /dev/urandom
69 * on Illumos, which uses a "FIPS 186-2 algorithm". No user of the SPL's
70 * random_get_pseudo_bytes() needs bytes that are of cryptographic quality, so
71 * we can implement it using a fast PRNG that we seed using Linux' actual
72 * equivalent to random_get_pseudo_bytes(). We do this by providing each CPU
73 * with an independent seed so that all calls to random_get_pseudo_bytes() are
74 * free of atomic instructions.
76 * A consequence of using a fast PRNG is that using random_get_pseudo_bytes()
77 * to generate words larger than 128 bits will paradoxically be limited to
78 * `2^128 - 1` possibilities. This is because we have a sequence of `2^128 - 1`
79 * 128-bit words and selecting the first will implicitly select the second. If
80 * a caller finds this behavior undesireable, random_get_bytes() should be used
83 * XXX: Linux interrupt handlers that trigger within the critical section
84 * formed by `s[1] = xp[1];` and `xp[0] = s[0];` and call this function will
85 * see the same numbers. Nothing in the code currently calls this in an
86 * interrupt handler, so this is considered to be okay. If that becomes a
87 * problem, we could create a set of per-cpu variables for interrupt handlers
88 * and use them when in_interrupt() from linux/preempt_mask.h evaluates to
91 static DEFINE_PER_CPU(uint64_t[2], spl_pseudo_entropy
);
94 * spl_rand_next()/spl_rand_jump() are copied from the following CC-0 licensed
97 * http://xorshift.di.unimi.it/xorshift128plus.c
100 static inline uint64_t
101 spl_rand_next(uint64_t *s
) {
103 const uint64_t s0
= s
[1];
106 s
[1] = s1
^ s0
^ (s1
>> 18) ^ (s0
>> 5); // b, c
111 spl_rand_jump(uint64_t *s
) {
112 static const uint64_t JUMP
[] = { 0x8a5cd789635d2dff, 0x121fd2155c472f96 };
117 for(i
= 0; i
< sizeof JUMP
/ sizeof *JUMP
; i
++)
118 for(b
= 0; b
< 64; b
++) {
119 if (JUMP
[i
] & 1ULL << b
) {
123 (void) spl_rand_next(s
);
131 random_get_pseudo_bytes(uint8_t *ptr
, size_t len
)
137 xp
= get_cpu_var(spl_pseudo_entropy
);
145 uint8_t byte
[sizeof (uint64_t)];
147 int i
= MIN(len
, sizeof (uint64_t));
150 entropy
.ui64
= spl_rand_next(s
);
153 *ptr
++ = entropy
.byte
[i
];
159 put_cpu_var(spl_pseudo_entropy
);
165 EXPORT_SYMBOL(random_get_pseudo_bytes
);
167 #if BITS_PER_LONG == 32
169 * Support 64/64 => 64 division on a 32-bit platform. While the kernel
170 * provides a div64_u64() function for this we do not use it because the
171 * implementation is flawed. There are cases which return incorrect
172 * results as late as linux-2.6.35. Until this is fixed upstream the
173 * spl must provide its own implementation.
175 * This implementation is a slightly modified version of the algorithm
176 * proposed by the book 'Hacker's Delight'. The original source can be
177 * found here and is available for use without restriction.
179 * http://www.hackersdelight.org/HDcode/newCode/divDouble.c
183 * Calculate number of leading of zeros for a 64-bit value.
192 if (x
<= 0x00000000FFFFFFFFULL
) {n
= n
+ 32; x
= x
<< 32;}
193 if (x
<= 0x0000FFFFFFFFFFFFULL
) {n
= n
+ 16; x
= x
<< 16;}
194 if (x
<= 0x00FFFFFFFFFFFFFFULL
) {n
= n
+ 8; x
= x
<< 8;}
195 if (x
<= 0x0FFFFFFFFFFFFFFFULL
) {n
= n
+ 4; x
= x
<< 4;}
196 if (x
<= 0x3FFFFFFFFFFFFFFFULL
) {n
= n
+ 2; x
= x
<< 2;}
197 if (x
<= 0x7FFFFFFFFFFFFFFFULL
) {n
= n
+ 1;}
203 * Newer kernels have a div_u64() function but we define our own
204 * to simplify portibility between kernel versions.
206 static inline uint64_t
207 __div_u64(uint64_t u
, uint32_t v
)
214 * Implementation of 64-bit unsigned division for 32-bit machines.
216 * First the procedure takes care of the case in which the divisor is a
217 * 32-bit quantity. There are two subcases: (1) If the left half of the
218 * dividend is less than the divisor, one execution of do_div() is all that
219 * is required (overflow is not possible). (2) Otherwise it does two
220 * divisions, using the grade school method.
223 __udivdi3(uint64_t u
, uint64_t v
)
225 uint64_t u0
, u1
, v1
, q0
, q1
, k
;
228 if (v
>> 32 == 0) { // If v < 2**32:
229 if (u
>> 32 < v
) { // If u/v cannot overflow,
230 return __div_u64(u
, v
); // just do one division.
231 } else { // If u/v would overflow:
232 u1
= u
>> 32; // Break u into two halves.
234 q1
= __div_u64(u1
, v
); // First quotient digit.
235 k
= u1
- q1
* v
; // First remainder, < v.
237 q0
= __div_u64(u0
, v
); // Seconds quotient digit.
238 return (q1
<< 32) + q0
;
240 } else { // If v >= 2**32:
241 n
= nlz64(v
); // 0 <= n <= 31.
242 v1
= (v
<< n
) >> 32; // Normalize divisor, MSB is 1.
243 u1
= u
>> 1; // To ensure no overflow.
244 q1
= __div_u64(u1
, v1
); // Get quotient from
245 q0
= (q1
<< n
) >> 31; // Undo normalization and
246 // division of u by 2.
247 if (q0
!= 0) // Make q0 correct or
248 q0
= q0
- 1; // too small by 1.
249 if ((u
- q0
* v
) >= v
)
250 q0
= q0
+ 1; // Now q0 is correct.
255 EXPORT_SYMBOL(__udivdi3
);
258 * Implementation of 64-bit signed division for 32-bit machines.
261 __divdi3(int64_t u
, int64_t v
)
264 q
= __udivdi3(abs64(u
), abs64(v
));
265 t
= (u
^ v
) >> 63; // If u, v have different
266 return (q
^ t
) - t
; // signs, negate q.
268 EXPORT_SYMBOL(__divdi3
);
271 * Implementation of 64-bit unsigned modulo for 32-bit machines.
274 __umoddi3(uint64_t dividend
, uint64_t divisor
)
276 return (dividend
- (divisor
* __udivdi3(dividend
, divisor
)));
278 EXPORT_SYMBOL(__umoddi3
);
280 #if defined(__arm) || defined(__arm__)
282 * Implementation of 64-bit (un)signed division for 32-bit arm machines.
284 * Run-time ABI for the ARM Architecture (page 20). A pair of (unsigned)
285 * long longs is returned in {{r0, r1}, {r2,r3}}, the quotient in {r0, r1},
286 * and the remainder in {r2, r3}. The return type is specifically left
287 * set to 'void' to ensure the compiler does not overwrite these registers
288 * during the return. All results are in registers as per ABI
291 __aeabi_uldivmod(uint64_t u
, uint64_t v
)
296 res
= __udivdi3(u
, v
);
297 mod
= __umoddi3(u
, v
);
299 register uint32_t r0
asm("r0") = (res
& 0xFFFFFFFF);
300 register uint32_t r1
asm("r1") = (res
>> 32);
301 register uint32_t r2
asm("r2") = (mod
& 0xFFFFFFFF);
302 register uint32_t r3
asm("r3") = (mod
>> 32);
305 : "+r"(r0
), "+r"(r1
), "+r"(r2
),"+r"(r3
) /* output */
306 : "r"(r0
), "r"(r1
), "r"(r2
), "r"(r3
)); /* input */
311 EXPORT_SYMBOL(__aeabi_uldivmod
);
314 __aeabi_ldivmod(int64_t u
, int64_t v
)
319 res
= __divdi3(u
, v
);
320 mod
= __umoddi3(u
, v
);
322 register uint32_t r0
asm("r0") = (res
& 0xFFFFFFFF);
323 register uint32_t r1
asm("r1") = (res
>> 32);
324 register uint32_t r2
asm("r2") = (mod
& 0xFFFFFFFF);
325 register uint32_t r3
asm("r3") = (mod
>> 32);
328 : "+r"(r0
), "+r"(r1
), "+r"(r2
),"+r"(r3
) /* output */
329 : "r"(r0
), "r"(r1
), "r"(r2
), "r"(r3
)); /* input */
334 EXPORT_SYMBOL(__aeabi_ldivmod
);
335 #endif /* __arm || __arm__ */
336 #endif /* BITS_PER_LONG */
338 /* NOTE: The strtoxx behavior is solely based on my reading of the Solaris
339 * ddi_strtol(9F) man page. I have not verified the behavior of these
340 * functions against their Solaris counterparts. It is possible that I
341 * may have misinterpreted the man page or the man page is incorrect.
343 int ddi_strtoul(const char *, char **, int, unsigned long *);
344 int ddi_strtol(const char *, char **, int, long *);
345 int ddi_strtoull(const char *, char **, int, unsigned long long *);
346 int ddi_strtoll(const char *, char **, int, long long *);
348 #define define_ddi_strtoux(type, valtype) \
349 int ddi_strtou##type(const char *str, char **endptr, \
350 int base, valtype *result) \
352 valtype last_value, value = 0; \
353 char *ptr = (char *)str; \
354 int flag = 1, digit; \
356 if (strlen(ptr) == 0) \
359 /* Auto-detect base based on prefix */ \
361 if (str[0] == '0') { \
362 if (tolower(str[1])=='x' && isxdigit(str[2])) { \
363 base = 16; /* hex */ \
365 } else if (str[1] >= '0' && str[1] < 8) { \
366 base = 8; /* octal */ \
372 base = 10; /* decimal */ \
378 digit = *ptr - '0'; \
379 else if (isalpha(*ptr)) \
380 digit = tolower(*ptr) - 'a' + 10; \
387 last_value = value; \
388 value = value * base + digit; \
389 if (last_value > value) /* Overflow */ \
400 *endptr = (char *)(flag ? ptr : str); \
405 #define define_ddi_strtox(type, valtype) \
406 int ddi_strto##type(const char *str, char **endptr, \
407 int base, valtype *result) \
412 rc = ddi_strtou##type(str + 1, endptr, base, result); \
414 if (*endptr == str + 1) \
415 *endptr = (char *)str; \
417 *result = -*result; \
420 rc = ddi_strtou##type(str, endptr, base, result); \
426 define_ddi_strtoux(l
, unsigned long)
427 define_ddi_strtox(l
, long)
428 define_ddi_strtoux(ll
, unsigned long long)
429 define_ddi_strtox(ll
, long long)
431 EXPORT_SYMBOL(ddi_strtoul
);
432 EXPORT_SYMBOL(ddi_strtol
);
433 EXPORT_SYMBOL(ddi_strtoll
);
434 EXPORT_SYMBOL(ddi_strtoull
);
437 ddi_copyin(const void *from
, void *to
, size_t len
, int flags
)
439 /* Fake ioctl() issued by kernel, 'from' is a kernel address */
440 if (flags
& FKIOCTL
) {
441 memcpy(to
, from
, len
);
445 return copyin(from
, to
, len
);
447 EXPORT_SYMBOL(ddi_copyin
);
450 ddi_copyout(const void *from
, void *to
, size_t len
, int flags
)
452 /* Fake ioctl() issued by kernel, 'from' is a kernel address */
453 if (flags
& FKIOCTL
) {
454 memcpy(to
, from
, len
);
458 return copyout(from
, to
, len
);
460 EXPORT_SYMBOL(ddi_copyout
);
462 #ifndef HAVE_PUT_TASK_STRUCT
464 * This is only a stub function which should never be used. The SPL should
465 * never be putting away the last reference on a task structure so this will
466 * not be called. However, we still need to define it so the module does not
467 * have undefined symbol at load time. That all said if this impossible
468 * thing does somehow happen PANIC immediately so we know about it.
471 __put_task_struct(struct task_struct
*t
)
473 PANIC("Unexpectly put last reference on task %d\n", (int)t
->pid
);
475 EXPORT_SYMBOL(__put_task_struct
);
476 #endif /* HAVE_PUT_TASK_STRUCT */
479 * Read the unique system identifier from the /etc/hostid file.
481 * The behavior of /usr/bin/hostid on Linux systems with the
482 * regular eglibc and coreutils is:
484 * 1. Generate the value if the /etc/hostid file does not exist
485 * or if the /etc/hostid file is less than four bytes in size.
487 * 2. If the /etc/hostid file is at least 4 bytes, then return
488 * the first four bytes [0..3] in native endian order.
490 * 3. Always ignore bytes [4..] if they exist in the file.
492 * Only the first four bytes are significant, even on systems that
493 * have a 64-bit word size.
497 * eglibc: sysdeps/unix/sysv/linux/gethostid.c
498 * coreutils: src/hostid.c
502 * The /etc/hostid file on Solaris is a text file that often reads:
507 * Directly copying this file to Linux results in a constant
508 * hostid of 4f442023 because the default comment constitutes
509 * the first four bytes of the file.
513 char *spl_hostid_path
= HW_HOSTID_PATH
;
514 module_param(spl_hostid_path
, charp
, 0444);
515 MODULE_PARM_DESC(spl_hostid_path
, "The system hostid file (/etc/hostid)");
525 file
= kobj_open_file(spl_hostid_path
);
527 if (file
== (struct _buf
*)-1)
530 result
= kobj_get_filesize(file
, &size
);
534 "SPL: kobj_get_filesize returned %i on %s\n",
535 result
, spl_hostid_path
);
536 kobj_close_file(file
);
540 if (size
< sizeof(HW_HOSTID_MASK
)) {
542 "SPL: Ignoring the %s file because it is %llu bytes; "
543 "expecting %lu bytes instead.\n", spl_hostid_path
,
544 size
, (unsigned long)sizeof(HW_HOSTID_MASK
));
545 kobj_close_file(file
);
549 /* Read directly into the variable like eglibc does. */
550 /* Short reads are okay; native behavior is preserved. */
551 result
= kobj_read_file(file
, (char *)&hostid
, sizeof(hostid
), 0);
555 "SPL: kobj_read_file returned %i on %s\n",
556 result
, spl_hostid_path
);
557 kobj_close_file(file
);
561 /* Mask down to 32 bits like coreutils does. */
562 spl_hostid
= hostid
& HW_HOSTID_MASK
;
563 kobj_close_file(file
);
568 zone_get_hostid(void *zone
)
570 static int first
= 1;
572 /* Only the global zone is supported */
573 ASSERT(zone
== NULL
);
578 spl_hostid
&= HW_HOSTID_MASK
;
580 * Get the hostid if it was not passed as a module parameter.
581 * Try reading the /etc/hostid file directly.
583 if (spl_hostid
== 0 && hostid_read())
587 printk(KERN_NOTICE
"SPL: using hostid 0x%08x\n",
588 (unsigned int) spl_hostid
);
593 EXPORT_SYMBOL(zone_get_hostid
);
600 rc
= spl_kmem_init();
604 rc
= spl_vmem_init();
614 * We initialize the random number generator with 128 bits of entropy from the
615 * system random number generator. In the improbable case that we have a zero
616 * seed, we fallback to the system jiffies, unless it is also zero, in which
617 * situation we use a preprogrammed seed. We step forward by 2^64 iterations to
618 * initialize each of the per-cpu seeds so that the sequences generated on each
619 * CPU are guaranteed to never overlap in practice.
622 spl_random_init(void)
627 get_random_bytes(s
, sizeof (s
));
629 if (s
[0] == 0 && s
[1] == 0) {
634 (void) memcpy(s
, "improbable seed", sizeof (s
));
636 printk("SPL: get_random_bytes() returned 0 "
637 "when generating random seed. Setting initial seed to "
638 "0x%016llx%016llx.", cpu_to_be64(s
[0]), cpu_to_be64(s
[1]));
641 for (i
= 0; i
< NR_CPUS
; i
++) {
642 uint64_t *wordp
= per_cpu(spl_pseudo_entropy
, i
);
665 if ((rc
= spl_kvmem_init()))
668 if ((rc
= spl_mutex_init()))
671 if ((rc
= spl_rw_init()))
674 if ((rc
= spl_tsd_init()))
677 if ((rc
= spl_taskq_init()))
680 if ((rc
= spl_kmem_cache_init()))
683 if ((rc
= spl_vn_init()))
686 if ((rc
= spl_proc_init()))
689 if ((rc
= spl_kstat_init()))
692 if ((rc
= spl_zlib_init()))
695 printk(KERN_NOTICE
"SPL: Loaded module v%s-%s%s\n", SPL_META_VERSION
,
696 SPL_META_RELEASE
, SPL_DEBUG_STR
);
706 spl_kmem_cache_fini();
718 printk(KERN_NOTICE
"SPL: Failed to Load Solaris Porting Layer "
719 "v%s-%s%s, rc = %d\n", SPL_META_VERSION
, SPL_META_RELEASE
,
728 printk(KERN_NOTICE
"SPL: Unloaded module v%s-%s%s\n",
729 SPL_META_VERSION
, SPL_META_RELEASE
, SPL_DEBUG_STR
);
734 spl_kmem_cache_fini();
742 module_init(spl_init
);
743 module_exit(spl_fini
);
745 MODULE_DESCRIPTION("Solaris Porting Layer");
746 MODULE_AUTHOR(SPL_META_AUTHOR
);
747 MODULE_LICENSE(SPL_META_LICENSE
);
748 MODULE_VERSION(SPL_META_VERSION
"-" SPL_META_RELEASE
);