arch/frv/kernel/futex.c

   1 /* futex.c: futex operations
   2  *
   3  * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/futex.h>
  13 #include <linux/uaccess.h>
  14 #include <asm/futex.h>
  15 #include <asm/errno.h>
  16
  17 /*
  18  * the various futex operations; MMU fault checking is ignored under no-MMU
  19  * conditions
  20  */
  21 static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr, int *_oldval)
  22 {
  23         int oldval, ret;
  24
  25         asm("0:                                         \n"
  26             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
  27             "   ckeq            icc3,cc7                \n"
  28             "1: ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
  29             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
  30             "2: cst.p           %3,%M0          ,cc3,#1 \n"
  31             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
  32             "   beq             icc3,#0,0b              \n"
  33             "   setlos          0,%2                    \n"
  34             "3:                                         \n"
  35             ".subsection 2                              \n"
  36             "4: setlos          %5,%2                   \n"
  37             "   bra             3b                      \n"
  38             ".previous                                  \n"
  39             ".section __ex_table,\"a\"                  \n"
  40             "   .balign         8                       \n"
  41             "   .long           1b,4b                   \n"
  42             "   .long           2b,4b                   \n"
  43             ".previous"
  44             : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
  45             : "3"(oparg), "i"(-EFAULT)
  46             : "memory", "cc7", "cc3", "icc3"
  47             );
  48
  49         *_oldval = oldval;
  50         return ret;
  51 }
  52
  53 static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr, int *_oldval)
  54 {
  55         int oldval, ret;
  56
  57         asm("0:                                         \n"
  58             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
  59             "   ckeq            icc3,cc7                \n"
  60             "1: ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
  61             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
  62             "   add             %1,%3,%3                \n"
  63             "2: cst.p           %3,%M0          ,cc3,#1 \n"
  64             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
  65             "   beq             icc3,#0,0b              \n"
  66             "   setlos          0,%2                    \n"
  67             "3:                                         \n"
  68             ".subsection 2                              \n"
  69             "4: setlos          %5,%2                   \n"
  70             "   bra             3b                      \n"
  71             ".previous                                  \n"
  72             ".section __ex_table,\"a\"                  \n"
  73             "   .balign         8                       \n"
  74             "   .long           1b,4b                   \n"
  75             "   .long           2b,4b                   \n"
  76             ".previous"
  77             : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
  78             : "3"(oparg), "i"(-EFAULT)
  79             : "memory", "cc7", "cc3", "icc3"
  80             );
  81
  82         *_oldval = oldval;
  83         return ret;
  84 }
  85
  86 static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr, int *_oldval)
  87 {
  88         int oldval, ret;
  89
  90         asm("0:                                         \n"
  91             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
  92             "   ckeq            icc3,cc7                \n"
  93             "1: ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
  94             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
  95             "   or              %1,%3,%3                \n"
  96             "2: cst.p           %3,%M0          ,cc3,#1 \n"
  97             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
  98             "   beq             icc3,#0,0b              \n"
  99             "   setlos          0,%2                    \n"
 100             "3:                                         \n"
 101             ".subsection 2                              \n"
 102             "4: setlos          %5,%2                   \n"
 103             "   bra             3b                      \n"
 104             ".previous                                  \n"
 105             ".section __ex_table,\"a\"                  \n"
 106             "   .balign         8                       \n"
 107             "   .long           1b,4b                   \n"
 108             "   .long           2b,4b                   \n"
 109             ".previous"
 110             : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
 111             : "3"(oparg), "i"(-EFAULT)
 112             : "memory", "cc7", "cc3", "icc3"
 113             );
 114
 115         *_oldval = oldval;
 116         return ret;
 117 }
 118
 119 static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr, int *_oldval)
 120 {
 121         int oldval, ret;
 122
 123         asm("0:                                         \n"
 124             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
 125             "   ckeq            icc3,cc7                \n"
 126             "1: ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
 127             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
 128             "   and             %1,%3,%3                \n"
 129             "2: cst.p           %3,%M0          ,cc3,#1 \n"
 130             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
 131             "   beq             icc3,#0,0b              \n"
 132             "   setlos          0,%2                    \n"
 133             "3:                                         \n"
 134             ".subsection 2                              \n"
 135             "4: setlos          %5,%2                   \n"
 136             "   bra             3b                      \n"
 137             ".previous                                  \n"
 138             ".section __ex_table,\"a\"                  \n"
 139             "   .balign         8                       \n"
 140             "   .long           1b,4b                   \n"
 141             "   .long           2b,4b                   \n"
 142             ".previous"
 143             : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
 144             : "3"(oparg), "i"(-EFAULT)
 145             : "memory", "cc7", "cc3", "icc3"
 146             );
 147
 148         *_oldval = oldval;
 149         return ret;
 150 }
 151
 152 static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr, int *_oldval)
 153 {
 154         int oldval, ret;
 155
 156         asm("0:                                         \n"
 157             "   orcc            gr0,gr0,gr0,icc3        \n"     /* set ICC3.Z */
 158             "   ckeq            icc3,cc7                \n"
 159             "1: ld.p            %M0,%1                  \n"     /* LD.P/ORCR must be atomic */
 160             "   orcr            cc7,cc7,cc3             \n"     /* set CC3 to true */
 161             "   xor             %1,%3,%3                \n"
 162             "2: cst.p           %3,%M0          ,cc3,#1 \n"
 163             "   corcc           gr29,gr29,gr0   ,cc3,#1 \n"     /* clear ICC3.Z if store happens */
 164             "   beq             icc3,#0,0b              \n"
 165             "   setlos          0,%2                    \n"
 166             "3:                                         \n"
 167             ".subsection 2                              \n"
 168             "4: setlos          %5,%2                   \n"
 169             "   bra             3b                      \n"
 170             ".previous                                  \n"
 171             ".section __ex_table,\"a\"                  \n"
 172             "   .balign         8                       \n"
 173             "   .long           1b,4b                   \n"
 174             "   .long           2b,4b                   \n"
 175             ".previous"
 176             : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
 177             : "3"(oparg), "i"(-EFAULT)
 178             : "memory", "cc7", "cc3", "icc3"
 179             );
 180
 181         *_oldval = oldval;
 182         return ret;
 183 }
 184
 185 /*****************************************************************************/
 186 /*
 187  * do the futex operations
 188  */
 189 int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
 190 {
 191         int op = (encoded_op >> 28) & 7;
 192         int cmp = (encoded_op >> 24) & 15;
 193         int oparg = (encoded_op << 8) >> 20;
 194         int cmparg = (encoded_op << 20) >> 20;
 195         int oldval = 0, ret;
 196
 197         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
 198                 oparg = 1 << oparg;
 199
 200         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
 201                 return -EFAULT;
 202
 203         pagefault_disable();
 204
 205         switch (op) {
 206         case FUTEX_OP_SET:
 207                 ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);
 208                 break;
 209         case FUTEX_OP_ADD:
 210                 ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);
 211                 break;
 212         case FUTEX_OP_OR:
 213                 ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);
 214                 break;
 215         case FUTEX_OP_ANDN:
 216                 ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);
 217                 break;
 218         case FUTEX_OP_XOR:
 219                 ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);
 220                 break;
 221         default:
 222                 ret = -ENOSYS;
 223                 break;
 224         }
 225
 226         pagefault_enable();
 227
 228         if (!ret) {
 229                 switch (cmp) {
 230                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
 231                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
 232                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
 233                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
 234                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
 235                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
 236                 default: ret = -ENOSYS; break;
 237                 }
 238         }
 239
 240         return ret;
 241
 242 } /* end futex_atomic_op_inuser() */