| 1 | /* |
| 2 | * arch/ubicom32/lib/checksum.c |
| 3 | * Optimized checksum utilities for IP. |
| 4 | * |
| 5 | * (C) Copyright 2009, Ubicom, Inc. |
| 6 | * |
| 7 | * This file is part of the Ubicom32 Linux Kernel Port. |
| 8 | * |
| 9 | * The Ubicom32 Linux Kernel Port is free software: you can redistribute |
| 10 | * it and/or modify it under the terms of the GNU General Public License |
| 11 | * as published by the Free Software Foundation, either version 2 of the |
| 12 | * License, or (at your option) any later version. |
| 13 | * |
| 14 | * The Ubicom32 Linux Kernel Port is distributed in the hope that it |
| 15 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
| 16 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| 17 | * the GNU General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU General Public License |
| 20 | * along with the Ubicom32 Linux Kernel Port. If not, |
| 21 | * see <http://www.gnu.org/licenses/>. |
| 22 | * |
| 23 | * Ubicom32 implementation derived from (with many thanks): |
| 24 | * arch/m68knommu |
| 25 | * arch/blackfin |
| 26 | * arch/parisc |
| 27 | */ |
| 28 | /* |
| 29 | * INET An implementation of the TCP/IP protocol suite for the LINUX |
| 30 | * operating system. INET is implemented using the BSD Socket |
| 31 | * interface as the means of communication with the user level. |
| 32 | * |
| 33 | * IP/TCP/UDP checksumming routines |
| 34 | * |
| 35 | * Authors: Jorge Cwik, <jorge@laser.satlink.net> |
| 36 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> |
| 37 | * Tom May, <ftom@netcom.com> |
| 38 | * Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de> |
| 39 | * Lots of code moved from tcp.c and ip.c; see those files |
| 40 | * for more names. |
| 41 | * |
| 42 | * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: |
| 43 | * Fixed some nasty bugs, causing some horrible crashes. |
| 44 | * A: At some points, the sum (%0) was used as |
| 45 | * length-counter instead of the length counter |
| 46 | * (%1). Thanks to Roman Hodek for pointing this out. |
| 47 | * B: GCC seems to mess up if one uses too many |
| 48 | * data-registers to hold input values and one tries to |
| 49 | * specify d0 and d1 as scratch registers. Letting gcc choose these |
| 50 | * registers itself solves the problem. |
| 51 | * |
| 52 | * This program is free software; you can redistribute it and/or |
| 53 | * modify it under the terms of the GNU General Public License |
| 54 | * as published by the Free Software Foundation; either version |
| 55 | * 2 of the License, or (at your option) any later version. |
| 56 | */ |
| 57 | |
| 58 | /* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access kills, so most |
| 59 | of the assembly has to go. */ |
| 60 | |
| 61 | #include <linux/module.h> |
| 62 | #include <net/checksum.h> |
| 63 | |
| 64 | static unsigned long do_csum(const unsigned char * buff, int len) |
| 65 | { |
| 66 | int count; |
| 67 | unsigned long result = 0; |
| 68 | |
| 69 | /* |
| 70 | * The following optimized assembly code cannot handle data length less than 7 bytes! |
| 71 | */ |
| 72 | if (likely(len >= 7)) { |
| 73 | len -= (4 - (int)buff) & 3; |
| 74 | count = len >> 2; |
| 75 | asm ( |
| 76 | " sub.4 d15, #0, %2 \n\t" // set up for jump table |
| 77 | " and.4 d15, #(32-1), d15 \n\t" // d15 = (-m) & (32 - 1) |
| 78 | |
| 79 | " bfextu d14, %0, #2 \n\t" // test 2 LSB of buff |
| 80 | " jmpne.w.f 100f \n\t" |
| 81 | " add.4 %1, #0, %1 \n\t" // clear C |
| 82 | " moveai a3, #%%hi(1f) \n\t" // table jump |
| 83 | " lea.1 a3, %%lo(1f)(a3) \n\t" |
| 84 | " lea.4 a3, (a3,d15) \n\t" |
| 85 | " calli a3, 0(a3) \n\t" |
| 86 | |
| 87 | "100: sub.4 %0, %0, d14 \n\t" |
| 88 | " sub.4 d14, #4, d14 \n\t" |
| 89 | " lsl.4 d14, d14, #3 \n\t" |
| 90 | " add.4 %1, #0, %1 \n\t" // clear C |
| 91 | " moveai a3, #%%hi(1f) \n\t" // table jump |
| 92 | " lea.1 a3, %%lo(1f)(a3) \n\t" |
| 93 | " lea.4 a3, (a3,d15) \n\t" |
| 94 | " bfextu %1, (%0)4++, d14 \n\t" // read first partial word |
| 95 | " calli a3, 0(a3) \n\t" |
| 96 | #if 1 |
| 97 | "200: lsl.4 %3, %3, #3 \n\t" |
| 98 | " bfrvrs d15, (%0), #0 \n\t" // read last word (partial) |
| 99 | " bfextu d15, d15, %3 \n\t" |
| 100 | " bfrvrs d15, d15, #0 \n\t" |
| 101 | " add.4 %1, d15, %1 \n\t" |
| 102 | " addc %1, #0, %1 \n\t" // sample C again |
| 103 | " jmpt.w.t 2f \n\t" |
| 104 | #else |
| 105 | "200: move.1 d15, 0(%0) \n\t" |
| 106 | " lsl.4 d15, d15, #8 \n\t" |
| 107 | " add.4 %1, d15, %1 \n\t" |
| 108 | " addc %1, #0, %1 \n\t" // sample C again |
| 109 | " add.4 %3, #-1, %3 \n\t" |
| 110 | " jmpeq.w.t 2f \n\t" |
| 111 | |
| 112 | " move.1 d15, 1(%0) \n\t" |
| 113 | " add.4 %1, d15, %1 \n\t" |
| 114 | " addc %1, #0, %1 \n\t" // sample C again |
| 115 | " add.4 %3, #-1, %3 \n\t" |
| 116 | " jmpeq.w.t 2f \n\t" |
| 117 | |
| 118 | " move.1 d15, 2(%0) \n\t" |
| 119 | " lsl.4 d15, d15, #8 \n\t" |
| 120 | " add.4 %1, d15, %1 \n\t" |
| 121 | " addc %1, #0, %1 \n\t" // sample C again |
| 122 | " jmpt.w.t 2f \n\t" |
| 123 | #endif |
| 124 | #if defined(IP7000) || defined(IP7000_REV2) |
| 125 | "300: swapb.2 %1, %1 \n\t" |
| 126 | #else |
| 127 | "300: shmrg.2 %1, %1, %1 \n\t" |
| 128 | " lsr.4 %1, %1, #8 \n\t" |
| 129 | " bfextu %1, %1, #16 \n\t" |
| 130 | #endif |
| 131 | " jmpt.w.t 3f \n\t" |
| 132 | |
| 133 | "1: add.4 %1, (%0)4++, %1 \n\t" // first add without C |
| 134 | " .rept 31 \n\t" |
| 135 | " addc %1, (%0)4++, %1 \n\t" |
| 136 | " .endr \n\t" |
| 137 | " addc %1, #0, %1 \n\t" // sample C again |
| 138 | " add.4 %2, #-32, %2 \n\t" |
| 139 | " jmpgt.w.t 1b \n\t" |
| 140 | |
| 141 | " and.4 %3, #3, %3 \n\t" // check n |
| 142 | " jmpne.w.f 200b \n\t" |
| 143 | |
| 144 | "2: .rept 2 \n\t" |
| 145 | " lsr.4 d15, %1, #16 \n\t" |
| 146 | " bfextu %1, %1, #16 \n\t" |
| 147 | " add.4 %1, d15, %1 \n\t" |
| 148 | " .endr \n\t" |
| 149 | " btst d14, #3 \n\t" // start from odd address (<< 3)? |
| 150 | " jmpne.w.f 300b \n\t" |
| 151 | "3: \n\t" |
| 152 | |
| 153 | : "+a"(buff), "+d"(result), "+d"(count), "+d"(len) |
| 154 | : |
| 155 | : "d15", "d14", "a3", "cc" |
| 156 | ); |
| 157 | |
| 158 | return result; |
| 159 | } |
| 160 | |
| 161 | /* |
| 162 | * handle a few bytes and fold result into 16-bit |
| 163 | */ |
| 164 | while (len-- > 0) { |
| 165 | result += (*buff++ << 8); |
| 166 | if (len) { |
| 167 | result += *buff++; |
| 168 | len--; |
| 169 | } |
| 170 | } |
| 171 | asm ( |
| 172 | " .rept 2 \n\t" |
| 173 | " lsr.4 d15, %0, #16 \n\t" |
| 174 | " bfextu %0, %0, #16 \n\t" |
| 175 | " add.4 %0, d15, %0 \n\t" |
| 176 | " .endr \n\t" |
| 177 | : "+d" (result) |
| 178 | : |
| 179 | : "d15", "cc" |
| 180 | ); |
| 181 | |
| 182 | return result; |
| 183 | } |
| 184 | |
| 185 | /* |
| 186 | * This is a version of ip_compute_csum() optimized for IP headers, |
| 187 | * which always checksum on 4 octet boundaries. |
| 188 | */ |
| 189 | __sum16 ip_fast_csum(const void *iph, unsigned int ihl) |
| 190 | { |
| 191 | return (__force __sum16)~do_csum(iph,ihl*4); |
| 192 | } |
| 193 | |
| 194 | /* |
| 195 | * computes the checksum of a memory block at buff, length len, |
| 196 | * and adds in "sum" (32-bit) |
| 197 | * |
| 198 | * returns a 32-bit number suitable for feeding into itself |
| 199 | * or csum_tcpudp_magic |
| 200 | * |
| 201 | * this function must be called with even lengths, except |
| 202 | * for the last fragment, which may be odd |
| 203 | * |
| 204 | * it's best to have buff aligned on a 32-bit boundary |
| 205 | */ |
| 206 | __wsum csum_partial(const void *buff, int len, __wsum sum) |
| 207 | { |
| 208 | unsigned int result = do_csum(buff, len); |
| 209 | |
| 210 | /* add in old sum, and carry.. */ |
| 211 | result += (__force u32)sum; |
| 212 | if ((__force u32)sum > result) |
| 213 | result += 1; |
| 214 | return (__force __wsum)result; |
| 215 | } |
| 216 | |
| 217 | EXPORT_SYMBOL(csum_partial); |
| 218 | |
| 219 | /* |
| 220 | * this routine is used for miscellaneous IP-like checksums, mainly |
| 221 | * in icmp.c |
| 222 | */ |
| 223 | __sum16 ip_compute_csum(const void *buff, int len) |
| 224 | { |
| 225 | return (__force __sum16)~do_csum(buff,len); |
| 226 | } |
| 227 | |
| 228 | /* |
| 229 | * copy from fs while checksumming, otherwise like csum_partial |
| 230 | */ |
| 231 | |
| 232 | __wsum |
| 233 | csum_partial_copy_from_user(const void __user *src, void *dst, |
| 234 | int len, __wsum sum, int *csum_err) |
| 235 | { |
| 236 | if (csum_err) *csum_err = 0; |
| 237 | memcpy(dst, (__force const void *)src, len); |
| 238 | return csum_partial(dst, len, sum); |
| 239 | } |
| 240 | |
| 241 | /* |
| 242 | * copy from ds while checksumming, otherwise like csum_partial |
| 243 | */ |
| 244 | |
| 245 | __wsum |
| 246 | csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum) |
| 247 | { |
| 248 | memcpy(dst, src, len); |
| 249 | return csum_partial(dst, len, sum); |
| 250 | } |
| 251 | |
