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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 <asm/fpumacro.h>
  24
  25 /* #define DEBUG_MNA */
  26
  27 enum direction {
  28         load,    /* ld, ldd, ldh, ldsh */
  29         store,   /* st, std, sth, stsh */
  30         both,    /* Swap, ldstub, cas, ... */
  31         fpld,
  32         fpst,
  33         invalid,
  34 };
  35
  36 #ifdef DEBUG_MNA
  37 static char *dirstrings[] = {
  38   "load", "store", "both", "fpload", "fpstore", "invalid"
  39 };
  40 #endif
  41
  42 static inline enum direction decode_direction(unsigned int insn)
  43 {
  44         unsigned long tmp = (insn >> 21) & 1;
  45
  46         if (!tmp)
  47                 return load;
  48         else {
  49                 switch ((insn>>19)&0xf) {
  50                 case 15: /* swap* */
  51                         return both;
  52                 default:
  53                         return store;
  54                 }
  55         }
  56 }
  57
  58 /* 16 = double-word, 8 = extra-word, 4 = word, 2 = half-word */
  59 static inline int decode_access_size(unsigned int insn)
  60 {
  61         unsigned int tmp;
  62
  63         tmp = ((insn >> 19) & 0xf);
  64         if (tmp == 11 || tmp == 14) /* ldx/stx */
  65                 return 8;
  66         tmp &= 3;
  67         if (!tmp)
  68                 return 4;
  69         else if (tmp == 3)
  70                 return 16;      /* ldd/std - Although it is actually 8 */
  71         else if (tmp == 2)
  72                 return 2;
  73         else {
  74                 printk("Impossible unaligned trap. insn=%08x\n", insn);
  75                 die_if_kernel("Byte sized unaligned access?!?!", current_thread_info()->kregs);
  76
  77                 /* GCC should never warn that control reaches the end
  78                  * of this function without returning a value because
  79                  * die_if_kernel() is marked with attribute 'noreturn'.
  80                  * Alas, some versions do...
  81                  */
  82
  83                 return 0;
  84         }
  85 }
  86
  87 static inline int decode_asi(unsigned int insn, struct pt_regs *regs)
  88 {
  89         if (insn & 0x800000) {
  90                 if (insn & 0x2000)
  91                         return (unsigned char)(regs->tstate >> 24);     /* %asi */
  92                 else
  93                         return (unsigned char)(insn >> 5);              /* imm_asi */
  94         } else
  95                 return ASI_P;
  96 }
  97
  98 /* 0x400000 = signed, 0 = unsigned */
  99 static inline int decode_signedness(unsigned int insn)
 100 {
 101         return (insn & 0x400000);
 102 }
 103
 104 static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
 105                                        unsigned int rd, int from_kernel)
 106 {
 107         if (rs2 >= 16 || rs1 >= 16 || rd >= 16) {
 108                 if (from_kernel != 0)
 109                         __asm__ __volatile__("flushw");
 110                 else
 111                         flushw_user();
 112         }
 113 }
 114
 115 static inline long sign_extend_imm13(long imm)
 116 {
 117         return imm << 51 >> 51;
 118 }
 119
 120 static unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
 121 {
 122         unsigned long value;
 123
 124         if (reg < 16)
 125                 return (!reg ? 0 : regs->u_regs[reg]);
 126         if (regs->tstate & TSTATE_PRIV) {
 127                 struct reg_window *win;
 128                 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 129                 value = win->locals[reg - 16];
 130         } else if (test_thread_flag(TIF_32BIT)) {
 131                 struct reg_window32 __user *win32;
 132                 win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
 133                 get_user(value, &win32->locals[reg - 16]);
 134         } else {
 135                 struct reg_window __user *win;
 136                 win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 137                 get_user(value, &win->locals[reg - 16]);
 138         }
 139         return value;
 140 }
 141
 142 static unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
 143 {
 144         if (reg < 16)
 145                 return &regs->u_regs[reg];
 146         if (regs->tstate & TSTATE_PRIV) {
 147                 struct reg_window *win;
 148                 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 149                 return &win->locals[reg - 16];
 150         } else if (test_thread_flag(TIF_32BIT)) {
 151                 struct reg_window32 *win32;
 152                 win32 = (struct reg_window32 *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
 153                 return (unsigned long *)&win32->locals[reg - 16];
 154         } else {
 155                 struct reg_window *win;
 156                 win = (struct reg_window *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 157                 return &win->locals[reg - 16];
 158         }
 159 }
 160
 161 unsigned long compute_effective_address(struct pt_regs *regs,
 162                                         unsigned int insn, unsigned int rd)
 163 {
 164         unsigned int rs1 = (insn >> 14) & 0x1f;
 165         unsigned int rs2 = insn & 0x1f;
 166         int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
 167
 168         if (insn & 0x2000) {
 169                 maybe_flush_windows(rs1, 0, rd, from_kernel);
 170                 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
 171         } else {
 172                 maybe_flush_windows(rs1, rs2, rd, from_kernel);
 173                 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
 174         }
 175 }
 176
 177 /* This is just to make gcc think die_if_kernel does return... */
 178 static void __attribute_used__ unaligned_panic(char *str, struct pt_regs *regs)
 179 {
 180         die_if_kernel(str, regs);
 181 }
 182
 183 extern void do_int_load(unsigned long *dest_reg, int size,
 184                         unsigned long *saddr, int is_signed, int asi);
 185
 186 extern void __do_int_store(unsigned long *dst_addr, int size,
 187                            unsigned long *src_val, int asi);
 188
 189 static inline void do_int_store(int reg_num, int size, unsigned long *dst_addr,
 190                                 struct pt_regs *regs, int asi)
 191 {
 192         unsigned long zero = 0;
 193         unsigned long *src_val = &zero;
 194
 195         if (size == 16) {
 196                 size = 8;
 197                 zero = (((long)(reg_num ?
 198                         (unsigned)fetch_reg(reg_num, regs) : 0)) << 32) |
 199                         (unsigned)fetch_reg(reg_num + 1, regs);
 200         } else if (reg_num) {
 201                 src_val = fetch_reg_addr(reg_num, regs);
 202         }
 203         __do_int_store(dst_addr, size, src_val, asi);
 204 }
 205
 206 static inline void advance(struct pt_regs *regs)
 207 {
 208         regs->tpc   = regs->tnpc;
 209         regs->tnpc += 4;
 210         if (test_thread_flag(TIF_32BIT)) {
 211                 regs->tpc &= 0xffffffff;
 212                 regs->tnpc &= 0xffffffff;
 213         }
 214 }
 215
 216 static inline int floating_point_load_or_store_p(unsigned int insn)
 217 {
 218         return (insn >> 24) & 1;
 219 }
 220
 221 static inline int ok_for_kernel(unsigned int insn)
 222 {
 223         return !floating_point_load_or_store_p(insn);
 224 }
 225
 226 void kernel_mna_trap_fault(void)
 227 {
 228         struct pt_regs *regs = current_thread_info()->kern_una_regs;
 229         unsigned int insn = current_thread_info()->kern_una_insn;
 230         unsigned long g2 = regs->u_regs[UREG_G2];
 231         unsigned long fixup = search_extables_range(regs->tpc, &g2);
 232
 233         if (!fixup) {
 234                 unsigned long address;
 235
 236                 address = compute_effective_address(regs, insn,
 237                                                     ((insn >> 25) & 0x1f));
 238                 if (address < PAGE_SIZE) {
 239                         printk(KERN_ALERT "Unable to handle kernel NULL "
 240                                "pointer dereference in mna handler");
 241                 } else
 242                         printk(KERN_ALERT "Unable to handle kernel paging "
 243                                "request in mna handler");
 244                 printk(KERN_ALERT " at virtual address %016lx\n",address);
 245                 printk(KERN_ALERT "current->{active_,}mm->context = %016lx\n",
 246                         (current->mm ? CTX_HWBITS(current->mm->context) :
 247                         CTX_HWBITS(current->active_mm->context)));
 248                 printk(KERN_ALERT "current->{active_,}mm->pgd = %016lx\n",
 249                         (current->mm ? (unsigned long) current->mm->pgd :
 250                         (unsigned long) current->active_mm->pgd));
 251                 die_if_kernel("Oops", regs);
 252                 /* Not reached */
 253         }
 254         regs->tpc = fixup;
 255         regs->tnpc = regs->tpc + 4;
 256         regs->u_regs [UREG_G2] = g2;
 257
 258         regs->tstate &= ~TSTATE_ASI;
 259         regs->tstate |= (ASI_AIUS << 24UL);
 260 }
 261
 262 asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn, unsigned long sfar, unsigned long sfsr)
 263 {
 264         enum direction dir = decode_direction(insn);
 265         int size = decode_access_size(insn);
 266
 267         current_thread_info()->kern_una_regs = regs;
 268         current_thread_info()->kern_una_insn = insn;
 269
 270         if (!ok_for_kernel(insn) || dir == both) {
 271                 printk("Unsupported unaligned load/store trap for kernel "
 272                        "at <%016lx>.\n", regs->tpc);
 273                 unaligned_panic("Kernel does fpu/atomic "
 274                                 "unaligned load/store.", regs);
 275
 276                 kernel_mna_trap_fault();
 277         } else {
 278                 unsigned long addr;
 279
 280                 addr = compute_effective_address(regs, insn,
 281                                                  ((insn >> 25) & 0x1f));
 282 #ifdef DEBUG_MNA
 283                 printk("KMNA: pc=%016lx [dir=%s addr=%016lx size=%d] "
 284                        "retpc[%016lx]\n",
 285                        regs->tpc, dirstrings[dir], addr, size,
 286                        regs->u_regs[UREG_RETPC]);
 287 #endif
 288                 switch (dir) {
 289                 case load:
 290                         do_int_load(fetch_reg_addr(((insn>>25)&0x1f), regs),
 291                                     size, (unsigned long *) addr,
 292                                     decode_signedness(insn),
 293                                     decode_asi(insn, regs));
 294                         break;
 295
 296                 case store:
 297                         do_int_store(((insn>>25)&0x1f), size,
 298                                      (unsigned long *) addr, regs,
 299                                      decode_asi(insn, regs));
 300                         break;
 301
 302                 default:
 303                         panic("Impossible kernel unaligned trap.");
 304                         /* Not reached... */
 305                 }
 306                 advance(regs);
 307         }
 308 }
 309
 310 static char popc_helper[] = {
 311 0, 1, 1, 2, 1, 2, 2, 3,
 312 1, 2, 2, 3, 2, 3, 3, 4,
 313 };
 314
 315 int handle_popc(u32 insn, struct pt_regs *regs)
 316 {
 317         u64 value;
 318         int ret, i, rd = ((insn >> 25) & 0x1f);
 319         int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
 320
 321         if (insn & 0x2000) {
 322                 maybe_flush_windows(0, 0, rd, from_kernel);
 323                 value = sign_extend_imm13(insn);
 324         } else {
 325                 maybe_flush_windows(0, insn & 0x1f, rd, from_kernel);
 326                 value = fetch_reg(insn & 0x1f, regs);
 327         }
 328         for (ret = 0, i = 0; i < 16; i++) {
 329                 ret += popc_helper[value & 0xf];
 330                 value >>= 4;
 331         }
 332         if (rd < 16) {
 333                 if (rd)
 334                         regs->u_regs[rd] = ret;
 335         } else {
 336                 if (test_thread_flag(TIF_32BIT)) {
 337                         struct reg_window32 __user *win32;
 338                         win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
 339                         put_user(ret, &win32->locals[rd - 16]);
 340                 } else {
 341                         struct reg_window __user *win;
 342                         win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS);
 343                         put_user(ret, &win->locals[rd - 16]);
 344                 }
 345         }
 346         advance(regs);
 347         return 1;
 348 }
 349
 350 extern void do_fpother(struct pt_regs *regs);
 351 extern void do_privact(struct pt_regs *regs);
 352 extern void spitfire_data_access_exception(struct pt_regs *regs,
 353                                            unsigned long sfsr,
 354                                            unsigned long sfar);
 355
 356 int handle_ldf_stq(u32 insn, struct pt_regs *regs)
 357 {
 358         unsigned long addr = compute_effective_address(regs, insn, 0);
 359         int freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
 360         struct fpustate *f = FPUSTATE;
 361         int asi = decode_asi(insn, regs);
 362         int flag = (freg < 32) ? FPRS_DL : FPRS_DU;
 363
 364         save_and_clear_fpu();
 365         current_thread_info()->xfsr[0] &= ~0x1c000;
 366         if (freg & 3) {
 367                 current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
 368                 do_fpother(regs);
 369                 return 0;
 370         }
 371         if (insn & 0x200000) {
 372                 /* STQ */
 373                 u64 first = 0, second = 0;
 374
 375                 if (current_thread_info()->fpsaved[0] & flag) {
 376                         first = *(u64 *)&f->regs[freg];
 377                         second = *(u64 *)&f->regs[freg+2];
 378                 }
 379                 if (asi < 0x80) {
 380                         do_privact(regs);
 381                         return 1;
 382                 }
 383                 switch (asi) {
 384                 case ASI_P:
 385                 case ASI_S: break;
 386                 case ASI_PL:
 387                 case ASI_SL:
 388                         {
 389                                 /* Need to convert endians */
 390                                 u64 tmp = __swab64p(&first);
 391
 392                                 first = __swab64p(&second);
 393                                 second = tmp;
 394                                 break;
 395                         }
 396                 default:
 397                         spitfire_data_access_exception(regs, 0, addr);
 398                         return 1;
 399                 }
 400                 if (put_user (first >> 32, (u32 __user *)addr) ||
 401                     __put_user ((u32)first, (u32 __user *)(addr + 4)) ||
 402                     __put_user (second >> 32, (u32 __user *)(addr + 8)) ||
 403                     __put_user ((u32)second, (u32 __user *)(addr + 12))) {
 404                         spitfire_data_access_exception(regs, 0, addr);
 405                         return 1;
 406                 }
 407         } else {
 408                 /* LDF, LDDF, LDQF */
 409                 u32 data[4] __attribute__ ((aligned(8)));
 410                 int size, i;
 411                 int err;
 412
 413                 if (asi < 0x80) {
 414                         do_privact(regs);
 415                         return 1;
 416                 } else if (asi > ASI_SNFL) {
 417                         spitfire_data_access_exception(regs, 0, addr);
 418                         return 1;
 419                 }
 420                 switch (insn & 0x180000) {
 421                 case 0x000000: size = 1; break;
 422                 case 0x100000: size = 4; break;
 423                 default: size = 2; break;
 424                 }
 425                 for (i = 0; i < size; i++)
 426                         data[i] = 0;
 427
 428                 err = get_user (data[0], (u32 __user *) addr);
 429                 if (!err) {
 430                         for (i = 1; i < size; i++)
 431                                 err |= __get_user (data[i], (u32 __user *)(addr + 4*i));
 432                 }
 433                 if (err && !(asi & 0x2 /* NF */)) {
 434                         spitfire_data_access_exception(regs, 0, addr);
 435                         return 1;
 436                 }
 437                 if (asi & 0x8) /* Little */ {
 438                         u64 tmp;
 439
 440                         switch (size) {
 441                         case 1: data[0] = le32_to_cpup(data + 0); break;
 442                         default:*(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 0));
 443                                 break;
 444                         case 4: tmp = le64_to_cpup((u64 *)(data + 0));
 445                                 *(u64 *)(data + 0) = le64_to_cpup((u64 *)(data + 2));
 446                                 *(u64 *)(data + 2) = tmp;
 447                                 break;
 448                         }
 449                 }
 450                 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
 451                         current_thread_info()->fpsaved[0] = FPRS_FEF;
 452                         current_thread_info()->gsr[0] = 0;
 453                 }
 454                 if (!(current_thread_info()->fpsaved[0] & flag)) {
 455                         if (freg < 32)
 456                                 memset(f->regs, 0, 32*sizeof(u32));
 457                         else
 458                                 memset(f->regs+32, 0, 32*sizeof(u32));
 459                 }
 460                 memcpy(f->regs + freg, data, size * 4);
 461                 current_thread_info()->fpsaved[0] |= flag;
 462         }
 463         advance(regs);
 464         return 1;
 465 }
 466
 467 void handle_ld_nf(u32 insn, struct pt_regs *regs)
 468 {
 469         int rd = ((insn >> 25) & 0x1f);
 470         int from_kernel = (regs->tstate & TSTATE_PRIV) != 0;
 471         unsigned long *reg;
 472
 473         maybe_flush_windows(0, 0, rd, from_kernel);
 474         reg = fetch_reg_addr(rd, regs);
 475         if (from_kernel || rd < 16) {
 476                 reg[0] = 0;
 477                 if ((insn & 0x780000) == 0x180000)
 478                         reg[1] = 0;
 479         } else if (test_thread_flag(TIF_32BIT)) {
 480                 put_user(0, (int __user *) reg);
 481                 if ((insn & 0x780000) == 0x180000)
 482                         put_user(0, ((int __user *) reg) + 1);
 483         } else {
 484                 put_user(0, (unsigned long __user *) reg);
 485                 if ((insn & 0x780000) == 0x180000)
 486                         put_user(0, (unsigned long __user *) reg + 1);
 487         }
 488         advance(regs);
 489 }
 490
 491 void handle_lddfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
 492 {
 493         unsigned long pc = regs->tpc;
 494         unsigned long tstate = regs->tstate;
 495         u32 insn;
 496         u32 first, second;
 497         u64 value;
 498         u8 asi, freg;
 499         int flag;
 500         struct fpustate *f = FPUSTATE;
 501
 502         if (tstate & TSTATE_PRIV)
 503                 die_if_kernel("lddfmna from kernel", regs);
 504         if (test_thread_flag(TIF_32BIT))
 505                 pc = (u32)pc;
 506         if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
 507                 asi = sfsr >> 16;
 508                 if ((asi > ASI_SNFL) ||
 509                     (asi < ASI_P))
 510                         goto daex;
 511                 if (get_user(first, (u32 __user *)sfar) ||
 512                      get_user(second, (u32 __user *)(sfar + 4))) {
 513                         if (asi & 0x2) /* NF */ {
 514                                 first = 0; second = 0;
 515                         } else
 516                                 goto daex;
 517                 }
 518                 save_and_clear_fpu();
 519                 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
 520                 value = (((u64)first) << 32) | second;
 521                 if (asi & 0x8) /* Little */
 522                         value = __swab64p(&value);
 523                 flag = (freg < 32) ? FPRS_DL : FPRS_DU;
 524                 if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
 525                         current_thread_info()->fpsaved[0] = FPRS_FEF;
 526                         current_thread_info()->gsr[0] = 0;
 527                 }
 528                 if (!(current_thread_info()->fpsaved[0] & flag)) {
 529                         if (freg < 32)
 530                                 memset(f->regs, 0, 32*sizeof(u32));
 531                         else
 532                                 memset(f->regs+32, 0, 32*sizeof(u32));
 533                 }
 534                 *(u64 *)(f->regs + freg) = value;
 535                 current_thread_info()->fpsaved[0] |= flag;
 536         } else {
 537 daex:           spitfire_data_access_exception(regs, sfsr, sfar);
 538                 return;
 539         }
 540         advance(regs);
 541         return;
 542 }
 543
 544 void handle_stdfmna(struct pt_regs *regs, unsigned long sfar, unsigned long sfsr)
 545 {
 546         unsigned long pc = regs->tpc;
 547         unsigned long tstate = regs->tstate;
 548         u32 insn;
 549         u64 value;
 550         u8 asi, freg;
 551         int flag;
 552         struct fpustate *f = FPUSTATE;
 553
 554         if (tstate & TSTATE_PRIV)
 555                 die_if_kernel("stdfmna from kernel", regs);
 556         if (test_thread_flag(TIF_32BIT))
 557                 pc = (u32)pc;
 558         if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
 559                 freg = ((insn >> 25) & 0x1e) | ((insn >> 20) & 0x20);
 560                 asi = sfsr >> 16;
 561                 value = 0;
 562                 flag = (freg < 32) ? FPRS_DL : FPRS_DU;
 563                 if ((asi > ASI_SNFL) ||
 564                     (asi < ASI_P))
 565                         goto daex;
 566                 save_and_clear_fpu();
 567                 if (current_thread_info()->fpsaved[0] & flag)
 568                         value = *(u64 *)&f->regs[freg];
 569                 switch (asi) {
 570                 case ASI_P:
 571                 case ASI_S: break;
 572                 case ASI_PL:
 573                 case ASI_SL:
 574                         value = __swab64p(&value); break;
 575                 default: goto daex;
 576                 }
 577                 if (put_user (value >> 32, (u32 __user *) sfar) ||
 578                     __put_user ((u32)value, (u32 __user *)(sfar + 4)))
 579                         goto daex;
 580         } else {
 581 daex:           spitfire_data_access_exception(regs, sfsr, sfar);
 582                 return;
 583         }
 584         advance(regs);
 585         return;
 586 }