arch/mips/loongson64/cop2-ex.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2014 Lemote Corporation.
   7  *   written by Huacai Chen <chenhc@lemote.com>
   8  *
   9  * based on arch/mips/cavium-octeon/cpu.c
  10  * Copyright (C) 2009 Wind River Systems,
  11  *   written by Ralf Baechle <ralf@linux-mips.org>
  12  */
  13 #include <linux/init.h>
  14 #include <linux/sched.h>
  15 #include <linux/notifier.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/sched/signal.h>
  19
  20 #include <asm/fpu.h>
  21 #include <asm/cop2.h>
  22 #include <asm/inst.h>
  23 #include <asm/branch.h>
  24 #include <asm/current.h>
  25 #include <asm/mipsregs.h>
  26 #include <asm/unaligned-emul.h>
  27
  28 static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
  29         void *data)
  30 {
  31         unsigned int res, fpu_owned;
  32         unsigned long ra, value, value_next;
  33         union mips_instruction insn;
  34         int fr = !test_thread_flag(TIF_32BIT_FPREGS);
  35         struct pt_regs *regs = (struct pt_regs *)data;
  36         void __user *addr = (void __user *)regs->cp0_badvaddr;
  37         unsigned int __user *pc = (unsigned int __user *)exception_epc(regs);
  38
  39         ra = regs->regs[31];
  40         __get_user(insn.word, pc);
  41
  42         switch (action) {
  43         case CU2_EXCEPTION:
  44                 preempt_disable();
  45                 fpu_owned = __is_fpu_owner();
  46                 if (!fr)
  47                         set_c0_status(ST0_CU1 | ST0_CU2);
  48                 else
  49                         set_c0_status(ST0_CU1 | ST0_CU2 | ST0_FR);
  50                 enable_fpu_hazard();
  51                 KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
  52                 if (fr)
  53                         KSTK_STATUS(current) |= ST0_FR;
  54                 else
  55                         KSTK_STATUS(current) &= ~ST0_FR;
  56                 /* If FPU is owned, we needn't init or restore fp */
  57                 if (!fpu_owned) {
  58                         set_thread_flag(TIF_USEDFPU);
  59                         init_fp_ctx(current);
  60                         _restore_fp(current);
  61                 }
  62                 preempt_enable();
  63
  64                 return NOTIFY_STOP;     /* Don't call default notifier */
  65
  66         case CU2_LWC2_OP:
  67                 if (insn.loongson3_lswc2_format.ls == 0)
  68                         goto sigbus;
  69
  70                 if (insn.loongson3_lswc2_format.fr == 0) {      /* gslq */
  71                         if (!access_ok(addr, 16))
  72                                 goto sigbus;
  73
  74                         LoadDW(addr, value, res);
  75                         if (res)
  76                                 goto fault;
  77
  78                         LoadDW(addr + 8, value_next, res);
  79                         if (res)
  80                                 goto fault;
  81
  82                         regs->regs[insn.loongson3_lswc2_format.rt] = value;
  83                         regs->regs[insn.loongson3_lswc2_format.rq] = value_next;
  84                         compute_return_epc(regs);
  85                 } else {                                        /* gslqc1 */
  86                         if (!access_ok(addr, 16))
  87                                 goto sigbus;
  88
  89                         lose_fpu(1);
  90                         LoadDW(addr, value, res);
  91                         if (res)
  92                                 goto fault;
  93
  94                         LoadDW(addr + 8, value_next, res);
  95                         if (res)
  96                                 goto fault;
  97
  98                         set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rt], 0, value);
  99                         set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rq], 0, value_next);
 100                         compute_return_epc(regs);
 101                         own_fpu(1);
 102                 }
 103                 return NOTIFY_STOP;     /* Don't call default notifier */
 104
 105         case CU2_SWC2_OP:
 106                 if (insn.loongson3_lswc2_format.ls == 0)
 107                         goto sigbus;
 108
 109                 if (insn.loongson3_lswc2_format.fr == 0) {      /* gssq */
 110                         if (!access_ok(addr, 16))
 111                                 goto sigbus;
 112
 113                         /* write upper 8 bytes first */
 114                         value_next = regs->regs[insn.loongson3_lswc2_format.rq];
 115
 116                         StoreDW(addr + 8, value_next, res);
 117                         if (res)
 118                                 goto fault;
 119                         value = regs->regs[insn.loongson3_lswc2_format.rt];
 120
 121                         StoreDW(addr, value, res);
 122                         if (res)
 123                                 goto fault;
 124
 125                         compute_return_epc(regs);
 126                 } else {                                        /* gssqc1 */
 127                         if (!access_ok(addr, 16))
 128                                 goto sigbus;
 129
 130                         lose_fpu(1);
 131                         value_next = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rq], 0);
 132
 133                         StoreDW(addr + 8, value_next, res);
 134                         if (res)
 135                                 goto fault;
 136
 137                         value = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lswc2_format.rt], 0);
 138
 139                         StoreDW(addr, value, res);
 140                         if (res)
 141                                 goto fault;
 142
 143                         compute_return_epc(regs);
 144                         own_fpu(1);
 145                 }
 146                 return NOTIFY_STOP;     /* Don't call default notifier */
 147
 148         case CU2_LDC2_OP:
 149                 switch (insn.loongson3_lsdc2_format.opcode1) {
 150                 /*
 151                  * Loongson-3 overridden ldc2 instructions.
 152                  * opcode1              instruction
 153                  *   0x1          gslhx: load 2 bytes to GPR
 154                  *   0x2          gslwx: load 4 bytes to GPR
 155                  *   0x3          gsldx: load 8 bytes to GPR
 156                  *   0x6          gslwxc1: load 4 bytes to FPR
 157                  *   0x7          gsldxc1: load 8 bytes to FPR
 158                  */
 159                 case 0x1:
 160                         if (!access_ok(addr, 2))
 161                                 goto sigbus;
 162
 163                         LoadHW(addr, value, res);
 164                         if (res)
 165                                 goto fault;
 166
 167                         compute_return_epc(regs);
 168                         regs->regs[insn.loongson3_lsdc2_format.rt] = value;
 169                         break;
 170                 case 0x2:
 171                         if (!access_ok(addr, 4))
 172                                 goto sigbus;
 173
 174                         LoadW(addr, value, res);
 175                         if (res)
 176                                 goto fault;
 177
 178                         compute_return_epc(regs);
 179                         regs->regs[insn.loongson3_lsdc2_format.rt] = value;
 180                         break;
 181                 case 0x3:
 182                         if (!access_ok(addr, 8))
 183                                 goto sigbus;
 184
 185                         LoadDW(addr, value, res);
 186                         if (res)
 187                                 goto fault;
 188
 189                         compute_return_epc(regs);
 190                         regs->regs[insn.loongson3_lsdc2_format.rt] = value;
 191                         break;
 192                 case 0x6:
 193                         die_if_kernel("Unaligned FP access in kernel code", regs);
 194                         BUG_ON(!used_math());
 195                         if (!access_ok(addr, 4))
 196                                 goto sigbus;
 197
 198                         lose_fpu(1);
 199                         LoadW(addr, value, res);
 200                         if (res)
 201                                 goto fault;
 202
 203                         set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0, value);
 204                         compute_return_epc(regs);
 205                         own_fpu(1);
 206
 207                         break;
 208                 case 0x7:
 209                         die_if_kernel("Unaligned FP access in kernel code", regs);
 210                         BUG_ON(!used_math());
 211                         if (!access_ok(addr, 8))
 212                                 goto sigbus;
 213
 214                         lose_fpu(1);
 215                         LoadDW(addr, value, res);
 216                         if (res)
 217                                 goto fault;
 218
 219                         set_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0, value);
 220                         compute_return_epc(regs);
 221                         own_fpu(1);
 222                         break;
 223
 224                 }
 225                 return NOTIFY_STOP;     /* Don't call default notifier */
 226
 227         case CU2_SDC2_OP:
 228                 switch (insn.loongson3_lsdc2_format.opcode1) {
 229                 /*
 230                  * Loongson-3 overridden sdc2 instructions.
 231                  * opcode1              instruction
 232                  *   0x1          gsshx: store 2 bytes from GPR
 233                  *   0x2          gsswx: store 4 bytes from GPR
 234                  *   0x3          gssdx: store 8 bytes from GPR
 235                  *   0x6          gsswxc1: store 4 bytes from FPR
 236                  *   0x7          gssdxc1: store 8 bytes from FPR
 237                  */
 238                 case 0x1:
 239                         if (!access_ok(addr, 2))
 240                                 goto sigbus;
 241
 242                         compute_return_epc(regs);
 243                         value = regs->regs[insn.loongson3_lsdc2_format.rt];
 244
 245                         StoreHW(addr, value, res);
 246                         if (res)
 247                                 goto fault;
 248
 249                         break;
 250                 case 0x2:
 251                         if (!access_ok(addr, 4))
 252                                 goto sigbus;
 253
 254                         compute_return_epc(regs);
 255                         value = regs->regs[insn.loongson3_lsdc2_format.rt];
 256
 257                         StoreW(addr, value, res);
 258                         if (res)
 259                                 goto fault;
 260
 261                         break;
 262                 case 0x3:
 263                         if (!access_ok(addr, 8))
 264                                 goto sigbus;
 265
 266                         compute_return_epc(regs);
 267                         value = regs->regs[insn.loongson3_lsdc2_format.rt];
 268
 269                         StoreDW(addr, value, res);
 270                         if (res)
 271                                 goto fault;
 272
 273                         break;
 274
 275                 case 0x6:
 276                         die_if_kernel("Unaligned FP access in kernel code", regs);
 277                         BUG_ON(!used_math());
 278
 279                         if (!access_ok(addr, 4))
 280                                 goto sigbus;
 281
 282                         lose_fpu(1);
 283                         value = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0);
 284
 285                         StoreW(addr, value, res);
 286                         if (res)
 287                                 goto fault;
 288
 289                         compute_return_epc(regs);
 290                         own_fpu(1);
 291
 292                         break;
 293                 case 0x7:
 294                         die_if_kernel("Unaligned FP access in kernel code", regs);
 295                         BUG_ON(!used_math());
 296
 297                         if (!access_ok(addr, 8))
 298                                 goto sigbus;
 299
 300                         lose_fpu(1);
 301                         value = get_fpr64(&current->thread.fpu.fpr[insn.loongson3_lsdc2_format.rt], 0);
 302
 303                         StoreDW(addr, value, res);
 304                         if (res)
 305                                 goto fault;
 306
 307                         compute_return_epc(regs);
 308                         own_fpu(1);
 309
 310                         break;
 311                 }
 312                 return NOTIFY_STOP;     /* Don't call default notifier */
 313         }
 314
 315         return NOTIFY_OK;               /* Let default notifier send signals */
 316
 317 fault:
 318         /* roll back jump/branch */
 319         regs->regs[31] = ra;
 320         regs->cp0_epc = (unsigned long)pc;
 321         /* Did we have an exception handler installed? */
 322         if (fixup_exception(regs))
 323                 return NOTIFY_STOP;     /* Don't call default notifier */
 324
 325         die_if_kernel("Unhandled kernel unaligned access", regs);
 326         force_sig(SIGSEGV);
 327
 328         return NOTIFY_STOP;     /* Don't call default notifier */
 329
 330 sigbus:
 331         die_if_kernel("Unhandled kernel unaligned access", regs);
 332         force_sig(SIGBUS);
 333
 334         return NOTIFY_STOP;     /* Don't call default notifier */
 335 }
 336
 337 static int __init loongson_cu2_setup(void)
 338 {
 339         return cu2_notifier(loongson_cu2_call, 0);
 340 }
 341 early_initcall(loongson_cu2_setup);