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a4bfd8ea1b
Up until now no SPL consumer attempted to perform signed 64-bit division so there was no need to support this. That has now changed so I adding 64-bit division support for 32-bit platforms. The signed implementation is based on the unsigned version. Since the have been several bug reports in the past concerning correct 64-bit division on 32-bit platforms I added some long over due regression tests. Much to my surprise the unsigned 64-bit division regression tests failed. This was surprising because __udivdi3() was implemented by simply calling div64_u64() which is provided by the kernel. This meant that the linux kernels 64-bit division algorithm on 32-bit platforms was flawed. After some investigation this turned out to be exactly the case. Because of this I was forced to abandon the kernel helper and instead to fully implement 64-bit division in the spl. There are several published implementation out there on how to do this properly and I settled on one proposed in the book Hacker's Delight. Their proposed algoritm is freely available without restriction and I have just modified it to be linux kernel friendly. The update implementation now passed all the unsigned and signed regression tests. This should be functional, but not fast, which is good enough for out purposes. If you want fast too I'd strongly suggest you upgrade to a 64-bit platform. I have also reported the kernel bug and we'll see if we can't get it fixed up stream.
550 lines
14 KiB
C
550 lines
14 KiB
C
/*****************************************************************************\
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* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
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* Copyright (C) 2007 The Regents of the University of California.
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* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
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* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
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* UCRL-CODE-235197
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*
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* This file is part of the SPL, Solaris Porting Layer.
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* For details, see <http://github.com/behlendorf/spl/>.
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*
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* The SPL is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* The SPL is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with the SPL. If not, see <http://www.gnu.org/licenses/>.
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*****************************************************************************
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* Solaris Porting Layer (SPL) Generic Implementation.
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\*****************************************************************************/
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#include <sys/sysmacros.h>
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#include <sys/systeminfo.h>
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#include <sys/vmsystm.h>
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#include <sys/vnode.h>
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#include <sys/kmem.h>
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#include <sys/mutex.h>
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#include <sys/rwlock.h>
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#include <sys/taskq.h>
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#include <sys/debug.h>
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#include <sys/proc.h>
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#include <sys/kstat.h>
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#include <sys/utsname.h>
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#include <sys/file.h>
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#include <linux/kmod.h>
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#include <linux/proc_compat.h>
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#ifdef DEBUG_SUBSYSTEM
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#undef DEBUG_SUBSYSTEM
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#endif
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#define DEBUG_SUBSYSTEM S_GENERIC
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char spl_version[16] = "SPL v" SPL_META_VERSION;
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EXPORT_SYMBOL(spl_version);
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long spl_hostid = 0;
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EXPORT_SYMBOL(spl_hostid);
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char hw_serial[HW_HOSTID_LEN] = "<none>";
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EXPORT_SYMBOL(hw_serial);
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proc_t p0 = { 0 };
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EXPORT_SYMBOL(p0);
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#ifndef HAVE_KALLSYMS_LOOKUP_NAME
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kallsyms_lookup_name_t spl_kallsyms_lookup_name_fn = SYMBOL_POISON;
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#endif
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int
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highbit(unsigned long i)
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{
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register int h = 1;
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ENTRY;
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if (i == 0)
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RETURN(0);
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#if BITS_PER_LONG == 64
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if (i & 0xffffffff00000000ul) {
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h += 32; i >>= 32;
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}
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#endif
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if (i & 0xffff0000) {
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h += 16; i >>= 16;
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}
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if (i & 0xff00) {
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h += 8; i >>= 8;
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}
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if (i & 0xf0) {
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h += 4; i >>= 4;
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}
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if (i & 0xc) {
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h += 2; i >>= 2;
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}
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if (i & 0x2) {
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h += 1;
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}
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RETURN(h);
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}
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EXPORT_SYMBOL(highbit);
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#if BITS_PER_LONG == 32
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/*
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* Support 64/64 => 64 division on a 32-bit platform. While the kernel
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* provides a div64_u64() function for this we do not use it because the
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* implementation is flawed. There are cases which return incorrect
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* results as late as linux-2.6.35. Until this is fixed upstream the
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* spl must provide its own implementation.
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*
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* This implementation is a slightly modified version of the algorithm
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* proposed by the book 'Hacker's Delight'. The original source can be
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* found here and is available for use without restriction.
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*
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* http://www.hackersdelight.org/HDcode/newCode/divDouble.c
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*/
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/*
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* Calculate number of leading of zeros for a 64-bit value.
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*/
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static int
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nlz64(uint64_t x) {
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register int n = 0;
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if (x == 0)
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return 64;
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if (x <= 0x00000000FFFFFFFFULL) {n = n + 32; x = x << 32;}
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if (x <= 0x0000FFFFFFFFFFFFULL) {n = n + 16; x = x << 16;}
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if (x <= 0x00FFFFFFFFFFFFFFULL) {n = n + 8; x = x << 8;}
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if (x <= 0x0FFFFFFFFFFFFFFFULL) {n = n + 4; x = x << 4;}
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if (x <= 0x3FFFFFFFFFFFFFFFULL) {n = n + 2; x = x << 2;}
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if (x <= 0x7FFFFFFFFFFFFFFFULL) {n = n + 1;}
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return n;
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}
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/*
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* Newer kernels have a div_u64() function but we define our own
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* to simplify portibility between kernel versions.
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*/
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static inline uint64_t
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__div_u64(uint64_t u, uint32_t v)
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{
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(void) do_div(u, v);
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return u;
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}
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/*
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* Implementation of 64-bit unsigned division for 32-bit machines.
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*
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* First the procedure takes care of the case in which the divisor is a
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* 32-bit quantity. There are two subcases: (1) If the left half of the
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* dividend is less than the divisor, one execution of do_div() is all that
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* is required (overflow is not possible). (2) Otherwise it does two
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* divisions, using the grade school method.
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*/
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uint64_t
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__udivdi3(uint64_t u, uint64_t v)
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{
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uint64_t u0, u1, v1, q0, q1, k;
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int n;
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if (v >> 32 == 0) { // If v < 2**32:
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if (u >> 32 < v) { // If u/v cannot overflow,
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return __div_u64(u, v); // just do one division.
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} else { // If u/v would overflow:
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u1 = u >> 32; // Break u into two halves.
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u0 = u & 0xFFFFFFFF;
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q1 = __div_u64(u1, v); // First quotient digit.
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k = u1 - q1 * v; // First remainder, < v.
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u0 += (k << 32);
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q0 = __div_u64(u0, v); // Seconds quotient digit.
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return (q1 << 32) + q0;
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}
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} else { // If v >= 2**32:
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n = nlz64(v); // 0 <= n <= 31.
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v1 = (v << n) >> 32; // Normalize divisor, MSB is 1.
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u1 = u >> 1; // To ensure no overflow.
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q1 = __div_u64(u1, v1); // Get quotient from
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q0 = (q1 << n) >> 31; // Undo normalization and
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// division of u by 2.
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if (q0 != 0) // Make q0 correct or
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q0 = q0 - 1; // too small by 1.
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if ((u - q0 * v) >= v)
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q0 = q0 + 1; // Now q0 is correct.
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return q0;
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}
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}
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EXPORT_SYMBOL(__udivdi3);
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/*
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* Implementation of 64-bit signed division for 32-bit machines.
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*/
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int64_t
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__divdi3(int64_t u, int64_t v)
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{
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int64_t q, t;
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q = __udivdi3(abs64(u), abs64(v));
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t = (u ^ v) >> 63; // If u, v have different
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return (q ^ t) - t; // signs, negate q.
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}
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EXPORT_SYMBOL(__divdi3);
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/*
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* Implementation of 64-bit unsigned modulo for 32-bit machines.
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*/
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uint64_t
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__umoddi3(uint64_t dividend, uint64_t divisor)
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{
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return (dividend - (divisor * __udivdi3(dividend, divisor)));
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}
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EXPORT_SYMBOL(__umoddi3);
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#endif /* BITS_PER_LONG */
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/* NOTE: The strtoxx behavior is solely based on my reading of the Solaris
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* ddi_strtol(9F) man page. I have not verified the behavior of these
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* functions against their Solaris counterparts. It is possible that I
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* may have misinterpreted the man page or the man page is incorrect.
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*/
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int ddi_strtoul(const char *, char **, int, unsigned long *);
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int ddi_strtol(const char *, char **, int, long *);
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int ddi_strtoull(const char *, char **, int, unsigned long long *);
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int ddi_strtoll(const char *, char **, int, long long *);
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#define define_ddi_strtoux(type, valtype) \
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int ddi_strtou##type(const char *str, char **endptr, \
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int base, valtype *result) \
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{ \
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valtype last_value, value = 0; \
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char *ptr = (char *)str; \
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int flag = 1, digit; \
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\
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if (strlen(ptr) == 0) \
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return EINVAL; \
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\
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/* Auto-detect base based on prefix */ \
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if (!base) { \
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if (str[0] == '0') { \
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if (tolower(str[1])=='x' && isxdigit(str[2])) { \
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base = 16; /* hex */ \
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ptr += 2; \
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} else if (str[1] >= '0' && str[1] < 8) { \
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base = 8; /* octal */ \
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ptr += 1; \
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} else { \
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return EINVAL; \
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} \
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} else { \
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base = 10; /* decimal */ \
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} \
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} \
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\
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while (1) { \
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if (isdigit(*ptr)) \
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digit = *ptr - '0'; \
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else if (isalpha(*ptr)) \
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digit = tolower(*ptr) - 'a' + 10; \
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else \
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break; \
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\
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if (digit >= base) \
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break; \
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\
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last_value = value; \
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value = value * base + digit; \
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if (last_value > value) /* Overflow */ \
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return ERANGE; \
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\
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flag = 1; \
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ptr++; \
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} \
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\
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if (flag) \
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*result = value; \
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\
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if (endptr) \
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*endptr = (char *)(flag ? ptr : str); \
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\
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return 0; \
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} \
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#define define_ddi_strtox(type, valtype) \
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int ddi_strto##type(const char *str, char **endptr, \
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int base, valtype *result) \
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{ \
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int rc; \
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\
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if (*str == '-') { \
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rc = ddi_strtou##type(str + 1, endptr, base, result); \
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if (!rc) { \
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if (*endptr == str + 1) \
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*endptr = (char *)str; \
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else \
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*result = -*result; \
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} \
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} else { \
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rc = ddi_strtou##type(str, endptr, base, result); \
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} \
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\
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return rc; \
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}
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define_ddi_strtoux(l, unsigned long)
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define_ddi_strtox(l, long)
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define_ddi_strtoux(ll, unsigned long long)
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define_ddi_strtox(ll, long long)
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EXPORT_SYMBOL(ddi_strtoul);
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EXPORT_SYMBOL(ddi_strtol);
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EXPORT_SYMBOL(ddi_strtoll);
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EXPORT_SYMBOL(ddi_strtoull);
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int
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ddi_copyin(const void *from, void *to, size_t len, int flags)
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{
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/* Fake ioctl() issued by kernel, 'from' is a kernel address */
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if (flags & FKIOCTL) {
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memcpy(to, from, len);
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return 0;
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}
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return copyin(from, to, len);
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}
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EXPORT_SYMBOL(ddi_copyin);
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int
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ddi_copyout(const void *from, void *to, size_t len, int flags)
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{
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/* Fake ioctl() issued by kernel, 'from' is a kernel address */
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if (flags & FKIOCTL) {
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memcpy(to, from, len);
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return 0;
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}
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return copyout(from, to, len);
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}
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EXPORT_SYMBOL(ddi_copyout);
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#ifndef HAVE_PUT_TASK_STRUCT
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/*
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* This is only a stub function which should never be used. The SPL should
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* never be putting away the last reference on a task structure so this will
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* not be called. However, we still need to define it so the module does not
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* have undefined symbol at load time. That all said if this impossible
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* thing does somehow happen SBUG() immediately so we know about it.
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*/
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void
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__put_task_struct(struct task_struct *t)
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{
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SBUG();
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}
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EXPORT_SYMBOL(__put_task_struct);
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#endif /* HAVE_PUT_TASK_STRUCT */
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struct new_utsname *__utsname(void)
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{
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#ifdef HAVE_INIT_UTSNAME
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return init_utsname();
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#else
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return &system_utsname;
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#endif
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}
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EXPORT_SYMBOL(__utsname);
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static int
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set_hostid(void)
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{
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char sh_path[] = "/bin/sh";
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char *argv[] = { sh_path,
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"-c",
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"/usr/bin/hostid >/proc/sys/kernel/spl/hostid",
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NULL };
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char *envp[] = { "HOME=/",
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"TERM=linux",
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"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
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NULL };
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int rc;
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/* Doing address resolution in the kernel is tricky and just
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* not a good idea in general. So to set the proper 'hw_serial'
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* use the usermodehelper support to ask '/bin/sh' to run
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* '/usr/bin/hostid' and redirect the result to /proc/sys/spl/hostid
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* for us to use. It's a horrific solution but it will do for now.
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*/
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rc = call_usermodehelper(sh_path, argv, envp, 1);
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if (rc)
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printk("SPL: Failed user helper '%s %s %s', rc = %d\n",
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argv[0], argv[1], argv[2], rc);
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return rc;
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}
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uint32_t
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zone_get_hostid(void *zone)
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{
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unsigned long hostid;
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/* Only the global zone is supported */
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ASSERT(zone == NULL);
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if (ddi_strtoul(hw_serial, NULL, HW_HOSTID_LEN-1, &hostid) != 0)
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return HW_INVALID_HOSTID;
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return (uint32_t)hostid;
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}
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EXPORT_SYMBOL(zone_get_hostid);
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#ifndef HAVE_KALLSYMS_LOOKUP_NAME
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/*
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* Because kallsyms_lookup_name() is no longer exported in the
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* mainline kernel we are forced to resort to somewhat drastic
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* measures. This function replaces the functionality by performing
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* an upcall to user space where /proc/kallsyms is consulted for
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* the requested address.
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*/
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#define GET_KALLSYMS_ADDR_CMD \
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"gawk '{ if ( $3 == \"kallsyms_lookup_name\") { print $1 } }' " \
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"/proc/kallsyms >/proc/sys/kernel/spl/kallsyms_lookup_name"
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static int
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set_kallsyms_lookup_name(void)
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{
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char sh_path[] = "/bin/sh";
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char *argv[] = { sh_path,
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"-c",
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GET_KALLSYMS_ADDR_CMD,
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NULL };
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char *envp[] = { "HOME=/",
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"TERM=linux",
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"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
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NULL };
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int rc;
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rc = call_usermodehelper(sh_path, argv, envp, 1);
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if (rc)
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printk("SPL: Failed user helper '%s %s %s', rc = %d\n",
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argv[0], argv[1], argv[2], rc);
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return rc;
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}
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#endif
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static int
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__init spl_init(void)
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{
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int rc = 0;
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if ((rc = debug_init()))
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return rc;
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if ((rc = spl_kmem_init()))
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GOTO(out1, rc);
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if ((rc = spl_mutex_init()))
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GOTO(out2, rc);
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if ((rc = spl_rw_init()))
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GOTO(out3, rc);
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if ((rc = spl_taskq_init()))
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GOTO(out4, rc);
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if ((rc = vn_init()))
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GOTO(out5, rc);
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if ((rc = proc_init()))
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GOTO(out6, rc);
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if ((rc = kstat_init()))
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GOTO(out7, rc);
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if ((rc = set_hostid()))
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GOTO(out8, rc = -EADDRNOTAVAIL);
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#ifndef HAVE_KALLSYMS_LOOKUP_NAME
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if ((rc = set_kallsyms_lookup_name()))
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GOTO(out8, rc = -EADDRNOTAVAIL);
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#endif /* HAVE_KALLSYMS_LOOKUP_NAME */
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if ((rc = spl_kmem_init_kallsyms_lookup()))
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GOTO(out8, rc);
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printk("SPL: Loaded Solaris Porting Layer v%s\n", SPL_META_VERSION);
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RETURN(rc);
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out8:
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kstat_fini();
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out7:
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proc_fini();
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out6:
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vn_fini();
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out5:
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spl_taskq_fini();
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out4:
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spl_rw_fini();
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out3:
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spl_mutex_fini();
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out2:
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spl_kmem_fini();
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out1:
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debug_fini();
|
|
|
|
printk("SPL: Failed to Load Solaris Porting Layer v%s, "
|
|
"rc = %d\n", SPL_META_VERSION, rc);
|
|
return rc;
|
|
}
|
|
|
|
static void
|
|
spl_fini(void)
|
|
{
|
|
ENTRY;
|
|
|
|
printk("SPL: Unloaded Solaris Porting Layer v%s\n", SPL_META_VERSION);
|
|
kstat_fini();
|
|
proc_fini();
|
|
vn_fini();
|
|
spl_taskq_fini();
|
|
spl_rw_fini();
|
|
spl_mutex_fini();
|
|
spl_kmem_fini();
|
|
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");
|