arch/mips/include/asm/stackframe.h

   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) 1994, 95, 96, 99, 2001 Ralf Baechle
   7  * Copyright (C) 1994, 1995, 1996 Paul M. Antoine.
   8  * Copyright (C) 1999 Silicon Graphics, Inc.
   9  * Copyright (C) 2007  Maciej W. Rozycki
  10  */
  11 #ifndef _ASM_STACKFRAME_H
  12 #define _ASM_STACKFRAME_H
  13
  14 #include <linux/threads.h>
  15
  16 #include <asm/asm.h>
  17 #include <asm/asmmacro.h>
  18 #include <asm/mipsregs.h>
  19 #include <asm/asm-offsets.h>
  20 #include <asm/thread_info.h>
  21
  22 /* Make the addition of cfi info a little easier. */
  23         .macro cfi_rel_offset reg offset=0 docfi=0
  24         .if \docfi
  25         .cfi_rel_offset \reg, \offset
  26         .endif
  27         .endm
  28
  29         .macro cfi_st reg offset=0 docfi=0
  30         LONG_S  \reg, \offset(sp)
  31         cfi_rel_offset \reg, \offset, \docfi
  32         .endm
  33
  34         .macro cfi_restore reg offset=0 docfi=0
  35         .if \docfi
  36         .cfi_restore \reg
  37         .endif
  38         .endm
  39
  40         .macro cfi_ld reg offset=0 docfi=0
  41         LONG_L  \reg, \offset(sp)
  42         cfi_restore \reg \offset \docfi
  43         .endm
  44
  45 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
  46 #define STATMASK 0x3f
  47 #else
  48 #define STATMASK 0x1f
  49 #endif
  50
  51                 .macro  SAVE_AT docfi=0
  52                 .set    push
  53                 .set    noat
  54                 cfi_st  $1, PT_R1, \docfi
  55                 .set    pop
  56                 .endm
  57
  58                 .macro  SAVE_TEMP docfi=0
  59 #ifdef CONFIG_CPU_HAS_SMARTMIPS
  60                 mflhxu  v1
  61                 LONG_S  v1, PT_LO(sp)
  62                 mflhxu  v1
  63                 LONG_S  v1, PT_HI(sp)
  64                 mflhxu  v1
  65                 LONG_S  v1, PT_ACX(sp)
  66 #elif !defined(CONFIG_CPU_MIPSR6)
  67                 mfhi    v1
  68 #endif
  69 #ifdef CONFIG_32BIT
  70                 cfi_st  $8, PT_R8, \docfi
  71                 cfi_st  $9, PT_R9, \docfi
  72 #endif
  73                 cfi_st  $10, PT_R10, \docfi
  74                 cfi_st  $11, PT_R11, \docfi
  75                 cfi_st  $12, PT_R12, \docfi
  76 #if !defined(CONFIG_CPU_HAS_SMARTMIPS) && !defined(CONFIG_CPU_MIPSR6)
  77                 LONG_S  v1, PT_HI(sp)
  78                 mflo    v1
  79 #endif
  80                 cfi_st  $13, PT_R13, \docfi
  81                 cfi_st  $14, PT_R14, \docfi
  82                 cfi_st  $15, PT_R15, \docfi
  83                 cfi_st  $24, PT_R24, \docfi
  84 #if !defined(CONFIG_CPU_HAS_SMARTMIPS) && !defined(CONFIG_CPU_MIPSR6)
  85                 LONG_S  v1, PT_LO(sp)
  86 #endif
  87 #ifdef CONFIG_CPU_CAVIUM_OCTEON
  88                 /*
  89                  * The Octeon multiplier state is affected by general
  90                  * multiply instructions. It must be saved before and
  91                  * kernel code might corrupt it
  92                  */
  93                 jal     octeon_mult_save
  94 #endif
  95                 .endm
  96
  97                 .macro  SAVE_STATIC docfi=0
  98                 cfi_st  $16, PT_R16, \docfi
  99                 cfi_st  $17, PT_R17, \docfi
 100                 cfi_st  $18, PT_R18, \docfi
 101                 cfi_st  $19, PT_R19, \docfi
 102                 cfi_st  $20, PT_R20, \docfi
 103                 cfi_st  $21, PT_R21, \docfi
 104                 cfi_st  $22, PT_R22, \docfi
 105                 cfi_st  $23, PT_R23, \docfi
 106                 cfi_st  $30, PT_R30, \docfi
 107                 .endm
 108
 109 /*
 110  * get_saved_sp returns the SP for the current CPU by looking in the
 111  * kernelsp array for it.  If tosp is set, it stores the current sp in
 112  * k0 and loads the new value in sp.  If not, it clobbers k0 and
 113  * stores the new value in k1, leaving sp unaffected.
 114  */
 115 #ifdef CONFIG_SMP
 116
 117                 /* SMP variation */
 118                 .macro  get_saved_sp docfi=0 tosp=0
 119                 ASM_CPUID_MFC0  k0, ASM_SMP_CPUID_REG
 120 #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
 121                 lui     k1, %hi(kernelsp)
 122 #else
 123                 lui     k1, %highest(kernelsp)
 124                 daddiu  k1, %higher(kernelsp)
 125                 dsll    k1, 16
 126                 daddiu  k1, %hi(kernelsp)
 127                 dsll    k1, 16
 128 #endif
 129                 LONG_SRL        k0, SMP_CPUID_PTRSHIFT
 130                 LONG_ADDU       k1, k0
 131                 .if \tosp
 132                 move    k0, sp
 133                 .if \docfi
 134                 .cfi_register sp, k0
 135                 .endif
 136                 LONG_L  sp, %lo(kernelsp)(k1)
 137                 .else
 138                 LONG_L  k1, %lo(kernelsp)(k1)
 139                 .endif
 140                 .endm
 141
 142                 .macro  set_saved_sp stackp temp temp2
 143                 ASM_CPUID_MFC0  \temp, ASM_SMP_CPUID_REG
 144                 LONG_SRL        \temp, SMP_CPUID_PTRSHIFT
 145                 LONG_S  \stackp, kernelsp(\temp)
 146                 .endm
 147 #else /* !CONFIG_SMP */
 148                 /* Uniprocessor variation */
 149                 .macro  get_saved_sp docfi=0 tosp=0
 150 #ifdef CONFIG_CPU_JUMP_WORKAROUNDS
 151                 /*
 152                  * Clear BTB (branch target buffer), forbid RAS (return address
 153                  * stack) to workaround the Out-of-order Issue in Loongson2F
 154                  * via its diagnostic register.
 155                  */
 156                 move    k0, ra
 157                 jal     1f
 158                  nop
 159 1:              jal     1f
 160                  nop
 161 1:              jal     1f
 162                  nop
 163 1:              jal     1f
 164                  nop
 165 1:              move    ra, k0
 166                 li      k0, 3
 167                 mtc0    k0, $22
 168 #endif /* CONFIG_CPU_JUMP_WORKAROUNDS */
 169 #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
 170                 lui     k1, %hi(kernelsp)
 171 #else
 172                 lui     k1, %highest(kernelsp)
 173                 daddiu  k1, %higher(kernelsp)
 174                 dsll    k1, k1, 16
 175                 daddiu  k1, %hi(kernelsp)
 176                 dsll    k1, k1, 16
 177 #endif
 178                 .if \tosp
 179                 move    k0, sp
 180                 .if \docfi
 181                 .cfi_register sp, k0
 182                 .endif
 183                 LONG_L  sp, %lo(kernelsp)(k1)
 184                 .else
 185                 LONG_L  k1, %lo(kernelsp)(k1)
 186                 .endif
 187                 .endm
 188
 189                 .macro  set_saved_sp stackp temp temp2
 190                 LONG_S  \stackp, kernelsp
 191                 .endm
 192 #endif
 193
 194                 .macro  SAVE_SOME docfi=0
 195                 .set    push
 196                 .set    noat
 197                 .set    reorder
 198                 mfc0    k0, CP0_STATUS
 199                 sll     k0, 3           /* extract cu0 bit */
 200                 .set    noreorder
 201                 bltz    k0, 8f
 202                  move   k0, sp
 203                 .if \docfi
 204                 .cfi_register sp, k0
 205                 .endif
 206 #ifdef CONFIG_EVA
 207                 /*
 208                  * Flush interAptiv's Return Prediction Stack (RPS) by writing
 209                  * EntryHi. Toggling Config7.RPS is slower and less portable.
 210                  *
 211                  * The RPS isn't automatically flushed when exceptions are
 212                  * taken, which can result in kernel mode speculative accesses
 213                  * to user addresses if the RPS mispredicts. That's harmless
 214                  * when user and kernel share the same address space, but with
 215                  * EVA the same user segments may be unmapped to kernel mode,
 216                  * even containing sensitive MMIO regions or invalid memory.
 217                  *
 218                  * This can happen when the kernel sets the return address to
 219                  * ret_from_* and jr's to the exception handler, which looks
 220                  * more like a tail call than a function call. If nested calls
 221                  * don't evict the last user address in the RPS, it will
 222                  * mispredict the return and fetch from a user controlled
 223                  * address into the icache.
 224                  *
 225                  * More recent EVA-capable cores with MAAR to restrict
 226                  * speculative accesses aren't affected.
 227                  */
 228                 MFC0    k0, CP0_ENTRYHI
 229                 MTC0    k0, CP0_ENTRYHI
 230 #endif
 231                 .set    reorder
 232                 /* Called from user mode, new stack. */
 233                 get_saved_sp docfi=\docfi tosp=1
 234 8:
 235 #ifdef CONFIG_CPU_DADDI_WORKAROUNDS
 236                 .set    at=k1
 237 #endif
 238                 PTR_SUBU sp, PT_SIZE
 239 #ifdef CONFIG_CPU_DADDI_WORKAROUNDS
 240                 .set    noat
 241 #endif
 242                 .if \docfi
 243                 .cfi_def_cfa sp,0
 244                 .endif
 245                 cfi_st  k0, PT_R29, \docfi
 246                 cfi_rel_offset  sp, PT_R29, \docfi
 247                 cfi_st  v1, PT_R3, \docfi
 248                 /*
 249                  * You might think that you don't need to save $0,
 250                  * but the FPU emulator and gdb remote debug stub
 251                  * need it to operate correctly
 252                  */
 253                 LONG_S  $0, PT_R0(sp)
 254                 mfc0    v1, CP0_STATUS
 255                 cfi_st  v0, PT_R2, \docfi
 256                 LONG_S  v1, PT_STATUS(sp)
 257                 cfi_st  $4, PT_R4, \docfi
 258                 mfc0    v1, CP0_CAUSE
 259                 cfi_st  $5, PT_R5, \docfi
 260                 LONG_S  v1, PT_CAUSE(sp)
 261                 cfi_st  $6, PT_R6, \docfi
 262                 cfi_st  ra, PT_R31, \docfi
 263                 MFC0    ra, CP0_EPC
 264                 cfi_st  $7, PT_R7, \docfi
 265 #ifdef CONFIG_64BIT
 266                 cfi_st  $8, PT_R8, \docfi
 267                 cfi_st  $9, PT_R9, \docfi
 268 #endif
 269                 LONG_S  ra, PT_EPC(sp)
 270                 .if \docfi
 271                 .cfi_rel_offset ra, PT_EPC
 272                 .endif
 273                 cfi_st  $25, PT_R25, \docfi
 274                 cfi_st  $28, PT_R28, \docfi
 275
 276                 /* Set thread_info if we're coming from user mode */
 277                 mfc0    k0, CP0_STATUS
 278                 sll     k0, 3           /* extract cu0 bit */
 279                 bltz    k0, 9f
 280
 281                 ori     $28, sp, _THREAD_MASK
 282                 xori    $28, _THREAD_MASK
 283 #ifdef CONFIG_CPU_CAVIUM_OCTEON
 284                 .set    mips64
 285                 pref    0, 0($28)       /* Prefetch the current pointer */
 286 #endif
 287 9:
 288                 .set    pop
 289                 .endm
 290
 291                 .macro  SAVE_ALL docfi=0
 292                 SAVE_SOME \docfi
 293                 SAVE_AT \docfi
 294                 SAVE_TEMP \docfi
 295                 SAVE_STATIC \docfi
 296                 .endm
 297
 298                 .macro  RESTORE_AT docfi=0
 299                 .set    push
 300                 .set    noat
 301                 cfi_ld  $1, PT_R1, \docfi
 302                 .set    pop
 303                 .endm
 304
 305                 .macro  RESTORE_TEMP docfi=0
 306 #ifdef CONFIG_CPU_CAVIUM_OCTEON
 307                 /* Restore the Octeon multiplier state */
 308                 jal     octeon_mult_restore
 309 #endif
 310 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 311                 LONG_L  $24, PT_ACX(sp)
 312                 mtlhx   $24
 313                 LONG_L  $24, PT_HI(sp)
 314                 mtlhx   $24
 315                 LONG_L  $24, PT_LO(sp)
 316                 mtlhx   $24
 317 #elif !defined(CONFIG_CPU_MIPSR6)
 318                 LONG_L  $24, PT_LO(sp)
 319                 mtlo    $24
 320                 LONG_L  $24, PT_HI(sp)
 321                 mthi    $24
 322 #endif
 323 #ifdef CONFIG_32BIT
 324                 cfi_ld  $8, PT_R8, \docfi
 325                 cfi_ld  $9, PT_R9, \docfi
 326 #endif
 327                 cfi_ld  $10, PT_R10, \docfi
 328                 cfi_ld  $11, PT_R11, \docfi
 329                 cfi_ld  $12, PT_R12, \docfi
 330                 cfi_ld  $13, PT_R13, \docfi
 331                 cfi_ld  $14, PT_R14, \docfi
 332                 cfi_ld  $15, PT_R15, \docfi
 333                 cfi_ld  $24, PT_R24, \docfi
 334                 .endm
 335
 336                 .macro  RESTORE_STATIC docfi=0
 337                 cfi_ld  $16, PT_R16, \docfi
 338                 cfi_ld  $17, PT_R17, \docfi
 339                 cfi_ld  $18, PT_R18, \docfi
 340                 cfi_ld  $19, PT_R19, \docfi
 341                 cfi_ld  $20, PT_R20, \docfi
 342                 cfi_ld  $21, PT_R21, \docfi
 343                 cfi_ld  $22, PT_R22, \docfi
 344                 cfi_ld  $23, PT_R23, \docfi
 345                 cfi_ld  $30, PT_R30, \docfi
 346                 .endm
 347
 348                 .macro  RESTORE_SP docfi=0
 349                 cfi_ld  sp, PT_R29, \docfi
 350                 .endm
 351
 352 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 353
 354                 .macro  RESTORE_SOME docfi=0
 355                 .set    push
 356                 .set    reorder
 357                 .set    noat
 358                 mfc0    a0, CP0_STATUS
 359                 li      v1, ST0_CU1 | ST0_IM
 360                 ori     a0, STATMASK
 361                 xori    a0, STATMASK
 362                 mtc0    a0, CP0_STATUS
 363                 and     a0, v1
 364                 LONG_L  v0, PT_STATUS(sp)
 365                 nor     v1, $0, v1
 366                 and     v0, v1
 367                 or      v0, a0
 368                 mtc0    v0, CP0_STATUS
 369                 cfi_ld  $31, PT_R31, \docfi
 370                 cfi_ld  $28, PT_R28, \docfi
 371                 cfi_ld  $25, PT_R25, \docfi
 372                 cfi_ld  $7,  PT_R7, \docfi
 373                 cfi_ld  $6,  PT_R6, \docfi
 374                 cfi_ld  $5,  PT_R5, \docfi
 375                 cfi_ld  $4,  PT_R4, \docfi
 376                 cfi_ld  $3,  PT_R3, \docfi
 377                 cfi_ld  $2,  PT_R2, \docfi
 378                 .set    pop
 379                 .endm
 380
 381                 .macro  RESTORE_SP_AND_RET docfi=0
 382                 .set    push
 383                 .set    noreorder
 384                 LONG_L  k0, PT_EPC(sp)
 385                 RESTORE_SP \docfi
 386                 jr      k0
 387                  rfe
 388                 .set    pop
 389                 .endm
 390
 391 #else
 392                 .macro  RESTORE_SOME docfi=0
 393                 .set    push
 394                 .set    reorder
 395                 .set    noat
 396                 mfc0    a0, CP0_STATUS
 397                 ori     a0, STATMASK
 398                 xori    a0, STATMASK
 399                 mtc0    a0, CP0_STATUS
 400                 li      v1, ST0_CU1 | ST0_FR | ST0_IM
 401                 and     a0, v1
 402                 LONG_L  v0, PT_STATUS(sp)
 403                 nor     v1, $0, v1
 404                 and     v0, v1
 405                 or      v0, a0
 406                 mtc0    v0, CP0_STATUS
 407                 LONG_L  v1, PT_EPC(sp)
 408                 MTC0    v1, CP0_EPC
 409                 cfi_ld  $31, PT_R31, \docfi
 410                 cfi_ld  $28, PT_R28, \docfi
 411                 cfi_ld  $25, PT_R25, \docfi
 412 #ifdef CONFIG_64BIT
 413                 cfi_ld  $8, PT_R8, \docfi
 414                 cfi_ld  $9, PT_R9, \docfi
 415 #endif
 416                 cfi_ld  $7,  PT_R7, \docfi
 417                 cfi_ld  $6,  PT_R6, \docfi
 418                 cfi_ld  $5,  PT_R5, \docfi
 419                 cfi_ld  $4,  PT_R4, \docfi
 420                 cfi_ld  $3,  PT_R3, \docfi
 421                 cfi_ld  $2,  PT_R2, \docfi
 422                 .set    pop
 423                 .endm
 424
 425                 .macro  RESTORE_SP_AND_RET docfi=0
 426                 RESTORE_SP \docfi
 427 #ifdef CONFIG_CPU_MIPSR6
 428                 eretnc
 429 #else
 430                 .set    push
 431                 .set    arch=r4000
 432                 eret
 433                 .set    pop
 434 #endif
 435                 .endm
 436
 437 #endif
 438
 439                 .macro  RESTORE_ALL docfi=0
 440                 RESTORE_TEMP \docfi
 441                 RESTORE_STATIC \docfi
 442                 RESTORE_AT \docfi
 443                 RESTORE_SOME \docfi
 444                 RESTORE_SP \docfi
 445                 .endm
 446
 447 /*
 448  * Move to kernel mode and disable interrupts.
 449  * Set cp0 enable bit as sign that we're running on the kernel stack
 450  */
 451                 .macro  CLI
 452                 mfc0    t0, CP0_STATUS
 453                 li      t1, ST0_CU0 | STATMASK
 454                 or      t0, t1
 455                 xori    t0, STATMASK
 456                 mtc0    t0, CP0_STATUS
 457                 irq_disable_hazard
 458                 .endm
 459
 460 /*
 461  * Move to kernel mode and enable interrupts.
 462  * Set cp0 enable bit as sign that we're running on the kernel stack
 463  */
 464                 .macro  STI
 465                 mfc0    t0, CP0_STATUS
 466                 li      t1, ST0_CU0 | STATMASK
 467                 or      t0, t1
 468                 xori    t0, STATMASK & ~1
 469                 mtc0    t0, CP0_STATUS
 470                 irq_enable_hazard
 471                 .endm
 472
 473 /*
 474  * Just move to kernel mode and leave interrupts as they are.  Note
 475  * for the R3000 this means copying the previous enable from IEp.
 476  * Set cp0 enable bit as sign that we're running on the kernel stack
 477  */
 478                 .macro  KMODE
 479                 mfc0    t0, CP0_STATUS
 480                 li      t1, ST0_CU0 | (STATMASK & ~1)
 481 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 482                 andi    t2, t0, ST0_IEP
 483                 srl     t2, 2
 484                 or      t0, t2
 485 #endif
 486                 or      t0, t1
 487                 xori    t0, STATMASK & ~1
 488                 mtc0    t0, CP0_STATUS
 489                 irq_disable_hazard
 490                 .endm
 491
 492 #endif /* _ASM_STACKFRAME_H */