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   1 /* $Id: unaligned.c,v 1.24 2002/02/09 19:49:31 davem Exp $
   2  * unaligned.c: Unaligned load/store trap handling with special
   3  *              cases for the kernel to do them more quickly.
   4  *
   5  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
   6  * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   7  */
   8
   9
  10 #include <linux/kernel.h>
  11 #include <linux/sched.h>
  12 #include <linux/mm.h>
  13 #include <linux/module.h>
  14 #include <asm/asi.h>
  15 #include <asm/ptrace.h>
  16 #include <asm/pstate.h>
  17 #include <asm/processor.h>
  18 #include <asm/system.h>
  19 #include <asm/uaccess.h>
  20 #include <linux/smp.h>
  21 #include <linux/smp_lock.h>
  22 #include <linux/bitops.h>
  23 #include <linux/kallsyms.h>
  24 #include <asm/fpumacro.h>
  25
  26 /* #define DEBUG_MNA */
  27
  28 enum direction {
  29         load,    /* ld, ldd, ldh, ldsh */
  30         store,   /* st, std, sth, stsh */
  31         both,    /* Swap, ldstub, cas, ... */
  32         fpld,
  33         fpst,
  34         invalid,
  35 };
  36
  37 #ifdef DEBUG_MNA
  38 static char *dirstrings[] = {
  39   "load", "store", "both", "fpload", "fpstore", "invalid"
  40 };
  41 #endif
  42
  43 static inline enum direction decode_direction(unsigned int insn)
  44 {
  45         unsigned long tmp = (insn >> 21) & 1;
  46
  47         if (!tmp)
  48                 return load;
  49         else {
  50                 switch ((insn>>19)&0xf) {
  51                 case 15: /* swap* */
  52                         return both;
  53                 default:
  54                         return store;
  55                 }
  56         }
  57 }
  58
  59 /* 16 = double-word, 8 = extra-word, 4 = word, 2 = half-word */
  60 static inline int decode_access_size(unsigned int insn)
  61 {
  62         unsigned int tmp;
  63
  64         tmp = ((insn >> 19) & 0xf);
  65         if (tmp == 11 || tmp == 14) /* ldx/stx */
  66                 return 8;
  67         tmp &= 3;
  68         if (!tmp)
  69                 return 4;
  70         else if (tmp == 3)
  71                 return 16;      /* ldd/std - Although it is actually 8 */
  72         else if (tmp == 2)
  73                 return 2;
  74         else {
  75                 printk("Impossible unaligned trap. insn=%08x\n", insn);
  76                 die_if_kernel("Byte sized unaligned access?!?!", current_thread_info()->kregs);
  77
  78                 /* GCC should never warn that control reaches the end
  79                  * of this function without returning a value because
  80                  * die_if_kernel() is marked with attribute 'noreturn'.
  81                  * Alas, some versions do...
  82                  */
  83
  84                 return 0;
  85         }
  86 }
  87
  88 static inline int decode_asi(unsigned int insn, struct pt_regs *regs)
  89 {
  90         if (insn & 0x800000) {
  91                 if (insn & 0x2000)
  92                         return (unsigned char)(regs->tstate >> 24);     /* %asi */
  93                 else
  94                         return (unsigned char)(insn >> 5);              /* imm_asi */
  95         } else
  96                 return ASI_P;
  97 }
  98
  99 /* 0x400000 = signed, 0 = unsigned */
 100 static inline int decode_signedness(unsigned int insn)
 101 {
 102         return (insn & 0x400000);
 103 }
 104
 105 static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
 106                                        unsigned int rd, int from_kernel)
 107 {
 108         if (rs2 >= 16 || rs1 >= 16 || rd >= 16) {
 109                 if (from_kernel != 0)
 110                         __asm__ __volatile__("flushw");
 111                 else
 112                         flushw_user();
 113         }
 114 }
 115
 116 static inline long sign_extend_imm13(long imm)
 117 {
 118         return imm << 51 >> 51;
 119 }
 120
 121 static unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
 122 {
 123         unsigned long value;
 124
 125         if (reg < 16)
 126                 return (!reg ? 0 : regs->u_regs[reg]);
 127         if (regs->tstate & TSTATE_PRIV) {
 128                 struct reg_window *win;
 129                 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 130                 value = win->locals[reg - 16];
 131         } else if (test_thread_flag(TIF_32BIT)) {
 132                 struct reg_window32 __user *win32;
 133                 win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
 134                 get_user(value, &win32->locals[reg - 16]);
 135         } else {
 136                 struct reg_window __user *win;
 137                 win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 138                 get_user(value, &win->locals[reg - 16]);
 139         }
 140         return value;
 141 }
 142
 143 static unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
 144 {
 145         if (reg < 16)
 146                 return &regs->u_regs[reg];
 147         if (regs->tstate & TSTATE_PRIV) {
 148                 struct reg_window *win;
 149                 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 150                 return &win->locals[reg - 16];
 151         } else if (test_thread_flag(TIF_32BIT)) {
 152                 struct reg_window32 *win32;
 153                 win32 = (struct reg_window32 *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
 154                 return (unsigned long *)&win32->locals[reg - 16];
 155         } else {
 156                 struct reg_window *win;
 157                 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 158                 return &win->locals[reg - 16];
 159         }
 160 }
 161
 162 unsigned long compute_effective_address(struct pt_regs *regs,
 163                                         unsigned int insn, unsigned int rd)
 164 {
 165         unsigned int rs1 = (insn >> 14) & 0x1f;
 166         unsigned int rs2 = insn & 0x1f;
 167         int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
 168
 169         if (insn & 0x2000) {
 170                 maybe_flush_windows(rs1, 0, rd, from_kernel);
 171                 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
 172         } else {
 173                 maybe_flush_windows(rs1, rs2, rd, from_kernel);
 174                 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
 175         }
 176 }
 177
 178 /* This is just to make gcc think die_if_kernel does return... */
 179 static void __attribute_used__ unaligned_panic(char *str, struct pt_regs *regs)
 180 {
 181         die_if_kernel(str, regs);
 182 }
 183
 184 extern int do_int_load(unsigned long *dest_reg, int size,
 185                        unsigned long *saddr, int is_signed, int asi);
 186
 187 extern int __do_int_store(unsigned long *dst_addr, int size,
 188                           unsigned long src_val, int asi);
 189
 190 static inline int do_int_store(int reg_num, int size, unsigned long *dst_addr,
 191                                struct pt_regs *regs, int asi, int orig_asi)
 192 {
 193         unsigned long zero = 0;
 194         unsigned long *src_val_p = &zero;
 195         unsigned long src_val;
 196
 197         if (size == 16) {
 198                 size = 8;
 199                 zero = (((long)(reg_num ?
 200                         (unsigned)fetch_reg(reg_num, regs) : 0)) << 32) |
 201                         (unsigned)fetch_reg(reg_num + 1, regs);
 202         } else if (reg_num) {
 203                 src_val_p = fetch_reg_addr(reg_num, regs);
 204         }
 205         src_val = *src_val_p;
 206         if (unlikely(asi != orig_asi)) {
 207                 switch (size) {
 208                 case 2:
 209                         src_val = swab16(src_val);
 210                         break;
 211                 case 4:
 212                         src_val = swab32(src_val);
 213                         break;
 214                 case 8:
 215                         src_val = swab64(src_val);
 216                         break;
 217                 case 16:
 218                 default:
 219                         BUG();
 220                         break;
 221                 };
 222         }
 223         return __do_int_store(dst_addr, size, src_val, asi);
 224 }
 225
 226 static inline void advance(struct pt_regs *regs)
 227 {
 228         regs->tpc   = regs->tnpc;
 229         regs->tnpc += 4;
 230         if (test_thread_flag(TIF_32BIT)) {
 231                 regs->tpc &= 0xffffffff;
 232                 regs->tnpc &= 0xffffffff;
 233         }
 234 }
 235
 236 static inline int floating_point_load_or_store_p(unsigned int insn)
 237 {
 238         return (insn >> 24) & 1;
 239 }
 240
 241 static inline int ok_for_kernel(unsigned int insn)
 242 {
 243         return !floating_point_load_or_store_p(insn);
 244 }
 245
 246 static void kernel_mna_trap_fault(void)
 247 {
 248         struct pt_regs *regs = current_thread_info()->kern_una_regs;
 249         unsigned int insn = current_thread_info()->kern_una_insn;
 250         const struct exception_table_entry *entry;
 251
 252         entry = search_exception_tables(regs->tpc);
 253         if (!entry) {
 254                 unsigned long address;
 255
 256                 address = compute_effective_address(regs, insn,
 257                                                     ((insn >> 25) & 0x1f));
 258                 if (address < PAGE_SIZE) {
 259                         printk(KERN_ALERT "Unable to handle kernel NULL "
 260                                "pointer dereference in mna handler");
 261                 } else
 262                         printk(KERN_ALERT "Unable to handle kernel paging "
 263                                "request in mna handler");
 264                 printk(KERN_ALERT " at virtual address %016lx\n",address);
 265                 printk(KERN_ALERT "current->{active_,}mm->context = %016lx\n",
 266                         (current->mm ? CTX_HWBITS(current->mm->context) :
 267                         CTX_HWBITS(current->active_mm->context)));
 268                 printk(KERN_ALERT "current->{active_,}mm->pgd = %016lx\n",
 269                         (current->mm ? (unsigned long) current->mm->pgd :
 270                         (unsigned long) current->active_mm->pgd));
 271                 die_if_kernel("Oops", regs);
 272                 /* Not reached */
 273         }
 274         regs->tpc = entry->fixup;
 275         regs->tnpc = regs->tpc + 4;
 276
 277         regs->tstate &= ~TSTATE_ASI;
 278         regs->tstate |= (ASI_AIUS << 24UL);
 279 }
 280
 281 asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
 282 {
 283         static unsigned long count, last_time;
 284         enum direction dir = decode_direction(insn);
 285         int size = decode_access_size(insn);
 286
 287         current_thread_info()->kern_una_regs = regs;
 288         current_thread_info()->kern_una_insn = insn;
 289
 290         if (jiffies - last_time > 5 * HZ)
 291                 count = 0;
 292         if (count < 5) {
 293                 last_time = jiffies;
 294                 count++;
 295                 printk("Kernel unaligned access at TPC[%lx] ", regs->tpc);
 296                 print_symbol("%s\n", regs->tpc);
 297         }
 298
 299         if (!ok_for_kernel(insn) || dir == both) {
 300                 printk("Unsupported unaligned load/store trap for kernel "
 301                        "at <%016lx>.\n", regs->tpc);
 302                 unaligned_panic("Kernel does fpu/atomic "
 303                                 "unaligned load/store.", regs);
 304
 305                 kernel_mna_trap_fault();
 306         } else {
 307                 unsigned long addr, *reg_addr;
 308                 int orig_asi, asi, err;
 309
 310                 addr = compute_effective_address(regs, insn,
 311                                                  ((insn >> 25) & 0x1f));
 312 #ifdef DEBUG_MNA
 313                 printk("KMNA: pc=%016lx [dir=%s addr=%016lx size=%d] "
 314                        "retpc[%016lx]\n",
 315                        regs->tpc, dirstrings[dir], addr, size,
 316                        regs->u_regs[UREG_RETPC]);
 317 #endif
 318                 orig_asi = asi = decode_asi(insn, regs);
 319                 switch (asi) {
 320                 case ASI_NL:
 321                 case ASI_AIUPL:
 322                 case ASI_AIUSL:
 323                 case ASI_PL:
 324                 case ASI_SL:
 325                 case ASI_PNFL:
 326                 case ASI_SNFL:
 327                         asi &= ~0x08;
 328                         break;
 329                 };
 330                 switch (dir) {
 331                 case load:
 332                         reg_addr = fetch_reg_addr(((insn>>25)&0x1f), regs);
 333                         err = do_int_load(reg_addr, size,
 334                                           (unsigned long *) addr,
 335                                           decode_signedness(insn), asi);
 336                         if (likely(!err) && unlikely(asi != orig_asi)) {
 337                                 unsigned long val_in = *reg_addr;
 338                                 switch (size) {
 339                                 case 2:
 340                                         val_in = swab16(val_in);
 341                                         break;
 342                                 case 4:
 343                                         val_in = swab32(val_in);
 344                                         break;
 345                                 case 8:
 346                                         val_in = swab64(val_in);
 347                                         break;
 348                                 case 16:
 349                                 default:
 350                                         BUG();
 351                                         break;
 352                                 };
 353                                 *reg_addr = val_in;
 354                         }
 355                         break;
 356
 357                 case store:
 358                         err = do_int_store(((insn>>25)&0x1f), size,
 359                                            (unsigned long *) addr, regs,
 360                                            asi, orig_asi);
 361                         break;
 362
 363                 default:
 364                         panic("Impossible kernel unaligned trap.");
 365                         /* Not reached... */
 366                 }
 367                 if (unlikely(err))
 368                         kernel_mna_trap_fault();
 369                 else
 370                         advance(regs);
 371         }
 372 }
 373
 374 static char popc_helper[] = {
 375 0, 1, 1, 2, 1, 2, 2, 3,
 376 1, 2, 2, 3, 2, 3, 3, 4,
 377 };
 378
 379 int handle_popc(u32 insn, struct pt_regs *regs)
 380 {
 381         u64 value;
 382         int ret, i, rd = ((insn >> 25) & 0x1f);
 383         int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
 384
 385         if (insn & 0x2000) {
 386                 maybe_flush_windows(0, 0, rd, from_kernel);
 387                 value = sign_extend_imm13(insn);
 388         } else {
 389                 maybe_flush_windows(0, insn & 0x1f, rd, from_kernel);
 390                 value = fetch_reg(insn & 0x1f, regs);
 391         }
 392         for (ret = 0, i = 0; i < 16; i++) {
 393                 ret += popc_helper[value & 0xf];
 394                 value >>= 4;
 395         }
 396         if (rd < 16) {
 397                 if (rd)
 398                         regs->u_regs[rd] = ret;
 399         } else {
 400                 if (test_thread_flag(TIF_32BIT)) {
 401                         struct reg_window32 __user *win32;
 402                         win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
 403                         put_user(ret, &win32->locals[rd - 16]);
 404                 } else {
 405                         struct reg_window __user *win;
 406                         win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 407                         put_user(ret, &win->locals[rd - 16]);
 408                 }
 409         }
 410         advance(regs);
 411         return 1;
 412 }
 413
 414 extern void do_fpother(struct pt_regs *regs);
 415 extern void do_privact(struct pt_regs *regs);
 416 extern void spitfire_data_access_exception(struct pt_regs *regs,
 417                                            unsigned long sfsr,
 418                                            unsigned long sfar);
 419 extern void sun4v_data_access_exception(struct pt_regs *regs,
 420                                         unsigned long addr,
 421                                         unsigned long type_ctx);
 422
 423 int handle_ldf_stq(u32 insn, struct pt_regs *regs)
 424 {
 425         unsigned long addr = compute_effective_address(regs, insn, 0);
 426         int freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
 427         struct fpustate *f = FPUSTATE;
 428         int asi = decode_asi(insn, regs);
 429         int flag = (freg < 32) ? FPRS_DL : FPRS_DU;
 430
 431         save_and_clear_fpu();
 432         current_thread_info()->xfsr[0] &= ~0x1c000;
 433         if (freg & 3) {
 434                 current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
 435                 do_fpother(regs);
 436                 return 0;
 437         }
 438         if (insn & 0x200000) {
 439                 /* STQ */
 440                 u64 first = 0, second = 0;
 441
 442                 if (current_thread_info()->fpsaved[0] & flag) {
 443                         first = *(u64 *)&f->regs[freg];
 444                         second = *(u64 *)&f->regs[freg+2];
 445                 }
 446                 if (asi < 0x80) {
 447                         do_privact(regs);
 448                         return 1;
 449                 }
 450                 switch (asi) {
 451                 case ASI_P:
 452                 case ASI_S: break;
 453                 case ASI_PL:
 454                 case ASI_SL:
 455                         {
 456                                 /* Need to convert endians */
 457                                 u64 tmp = __swab64p(&first);
 458
 459                                 first = __swab64p(&second);
 460                                 second = tmp;
 461                                 break;
 462                         }
 463                 default:
 464                         if (tlb_type == hypervisor)
 465                                 sun4v_data_access_exception(regs, addr, 0);
 466                         else
 467                                 spitfire_data_access_exception(regs, 0, addr);
 468                         return 1;
 469                 }
 470                 if (put_user (first >> 32, (u32 __user *)addr) ||
 471                     __put_user ((u32)first, (u32 __user *)(addr + 4)) ||
 472                     __put_user (second >> 32, (u32 __user *)(addr + 8)) ||
 473                     __put_user ((u32)second, (u32 __user *)(addr + 12))) {
 474                         if (tlb_type == hypervisor)
 475                                 sun4v_data_access_exception(regs, addr, 0);
 476                         else
 477                                 spitfire_data_access_exception(regs, 0, addr);
 478                         return 1;
 479                 }
 480         } else {
 481                 /* LDF, LDDF, LDQF */
 482                 u32 data[4] __attribute__ ((aligned(8)));
 483                 int size, i;
 484                 int err;
 485
 486                 if (asi < 0x80) {
 487                         do_privact(regs);
 488                         return 1;
 489                 } else if (asi > ASI_SNFL) {
 490                         if (tlb_type == hypervisor)
 491                                 sun4v_data_access_exception(regs, addr, 0);
 492                         else
 493                                 spitfire_data_access_exception(regs, 0, addr);
 494                         return 1;
 495                 }
 496                 switch (insn & 0x180000) {
 497                 case 0x000000: size = 1; break;
 498                 case 0x100000: size = 4; break;
 499                 default: size = 2; break;
 500                 }
 501                 for (i = 0; i < size; i++)
 502                         data[i] = 0;
 503
 504                 err = get_user (data[0], (u32 __user *) addr);
 505                 if (!err) {
 506                         for (i = 1; i < size; i++)
 507                                 err |= __get_user (data[i], (u32 __user *)(addr + 4*i));
 508                 }
 509                 if (err && !(asi & 0x2 /* NF */)) {
 510                         if (tlb_type == hypervisor)
 511                                 sun4v_data_access_exception(regs, addr, 0);
 512                         else
 513                                 spitfire_data_access_exception(regs, 0, addr);
 514                         return 1;
 515                 }
 516                 if (asi & 0x8) /* Little */ {
 517                         u64 tmp;
 518
 519                         switch (size) {
 520                         case 1: data[0] = le32_to_cpup(data + 0); break;
 521                         default:*(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 0));
 522                                 break;
 523                         case 4: tmp = le64_to_cpup((u64 *)(data + 0));
 524                                 *(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 2));
 525                                 *(u64 *)(data + 2) = tmp;
 526                                 break;
 527                         }
 528                 }
 529                 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
 530                         current_thread_info()->fpsaved[0] = FPRS_FEF;
 531                         current_thread_info()->gsr[0] = 0;
 532                 }
 533                 if (!(current_thread_info()->fpsaved[0] & flag)) {
 534                         if (freg < 32)
 535                                 memset(f->regs, 0, 32*sizeof(u32));
 536                         else
 537                                 memset(f->regs+32, 0, 32*sizeof(u32));
 538                 }
 539                 memcpy(f->regs + freg, data, size * 4);
 540                 current_thread_info()->fpsaved[0] |= flag;
 541         }
 542         advance(regs);
 543         return 1;
 544 }
 545
 546 void handle_ld_nf(u32 insn, struct pt_regs *regs)
 547 {
 548         int rd = ((insn >> 25) & 0x1f);
 549         int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
 550         unsigned long *reg;
 551
 552         maybe_flush_windows(0, 0, rd, from_kernel);
 553         reg = fetch_reg_addr(rd, regs);
 554         if (from_kernel || rd < 16) {
 555                 reg[0] = 0;
 556                 if ((insn & 0x780000) == 0x180000)
 557                         reg[1] = 0;
 558         } else if (test_thread_flag(TIF_32BIT)) {
 559                 put_user(0, (int __user *) reg);
 560                 if ((insn & 0x780000) == 0x180000)
 561                         put_user(0, ((int __user *) reg) + 1);
 562         } else {
 563                 put_user(0, (unsigned long __user *) reg);
 564                 if ((insn & 0x780000) == 0x180000)
 565                         put_user(0, (unsigned long __user *) reg + 1);
 566         }
 567         advance(regs);
 568 }
 569
 570 void handle_lddfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
 571 {
 572         unsigned long pc = regs->tpc;
 573         unsigned long tstate = regs->tstate;
 574         u32 insn;
 575         u32 first, second;
 576         u64 value;
 577         u8 freg;
 578         int flag;
 579         struct fpustate *f = FPUSTATE;
 580
 581         if (tstate & TSTATE_PRIV)
 582                 die_if_kernel("lddfmna from kernel", regs);
 583         if (test_thread_flag(TIF_32BIT))
 584                 pc = (u32)pc;
 585         if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
 586                 int asi = decode_asi(insn, regs);
 587                 if ((asi > ASI_SNFL) ||
 588                     (asi < ASI_P))
 589                         goto daex;
 590                 if (get_user(first, (u32 __user *)sfar) ||
 591                      get_user(second, (u32 __user *)(sfar + 4))) {
 592                         if (asi & 0x2) /* NF */ {
 593                                 first = 0; second = 0;
 594                         } else
 595                                 goto daex;
 596                 }
 597                 save_and_clear_fpu();
 598                 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
 599                 value = (((u64)first) << 32) | second;
 600                 if (asi & 0x8) /* Little */
 601                         value = __swab64p(&value);
 602                 flag = (freg < 32) ? FPRS_DL : FPRS_DU;
 603                 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
 604                         current_thread_info()->fpsaved[0] = FPRS_FEF;
 605                         current_thread_info()->gsr[0] = 0;
 606                 }
 607                 if (!(current_thread_info()->fpsaved[0] & flag)) {
 608                         if (freg < 32)
 609                                 memset(f->regs, 0, 32*sizeof(u32));
 610                         else
 611                                 memset(f->regs+32, 0, 32*sizeof(u32));
 612                 }
 613                 *(u64 *)(f->regs + freg) = value;
 614                 current_thread_info()->fpsaved[0] |= flag;
 615         } else {
 616 daex:
 617                 if (tlb_type == hypervisor)
 618                         sun4v_data_access_exception(regs, sfar, sfsr);
 619                 else
 620                         spitfire_data_access_exception(regs, sfsr, sfar);
 621                 return;
 622         }
 623         advance(regs);
 624         return;
 625 }
 626
 627 void handle_stdfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
 628 {
 629         unsigned long pc = regs->tpc;
 630         unsigned long tstate = regs->tstate;
 631         u32 insn;
 632         u64 value;
 633         u8 freg;
 634         int flag;
 635         struct fpustate *f = FPUSTATE;
 636
 637         if (tstate & TSTATE_PRIV)
 638                 die_if_kernel("stdfmna from kernel", regs);
 639         if (test_thread_flag(TIF_32BIT))
 640                 pc = (u32)pc;
 641         if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
 642                 int asi = decode_asi(insn, regs);
 643                 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
 644                 value = 0;
 645                 flag = (freg < 32) ? FPRS_DL : FPRS_DU;
 646                 if ((asi > ASI_SNFL) ||
 647                     (asi < ASI_P))
 648                         goto daex;
 649                 save_and_clear_fpu();
 650                 if (current_thread_info()->fpsaved[0] & flag)
 651                         value = *(u64 *)&f->regs[freg];
 652                 switch (asi) {
 653                 case ASI_P:
 654                 case ASI_S: break;
 655                 case ASI_PL:
 656                 case ASI_SL:
 657                         value = __swab64p(&value); break;
 658                 default: goto daex;
 659                 }
 660                 if (put_user (value >> 32, (u32 __user *) sfar) ||
 661                     __put_user ((u32)value, (u32 __user *)(sfar + 4)))
 662                         goto daex;
 663         } else {
 664 daex:
 665                 if (tlb_type == hypervisor)
 666                         sun4v_data_access_exception(regs, sfar, sfsr);
 667                 else
 668                         spitfire_data_access_exception(regs, sfsr, sfar);
 669                 return;
 670         }
 671         advance(regs);
 672         return;
 673 }