arch/arm/kernel/entry-common.S

   1 /*
   2  *  linux/arch/arm/kernel/entry-common.S
   3  *
   4  *  Copyright (C) 2000 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <asm/unistd.h>
  12 #include <asm/ftrace.h>
  13 #include <mach/entry-macro.S>
  14 #include <asm/unwind.h>
  15
  16 #include "entry-header.S"
  17
  18
  19         .align  5
  20 /*
  21  * This is the fast syscall return path.  We do as little as
  22  * possible here, and this includes saving r0 back into the SVC
  23  * stack.
  24  */
  25 ret_fast_syscall:
  26  UNWIND(.fnstart        )
  27  UNWIND(.cantunwind     )
  28         disable_irq                             @ disable interrupts
  29         ldr     r1, [tsk, #TI_FLAGS]
  30         tst     r1, #_TIF_WORK_MASK
  31         bne     fast_work_pending
  32
  33         /* perform architecture specific actions before user return */
  34         arch_ret_to_user r1, lr
  35
  36         restore_user_regs fast = 1, offset = S_OFF
  37  UNWIND(.fnend          )
  38
  39 /*
  40  * Ok, we need to do extra processing, enter the slow path.
  41  */
  42 fast_work_pending:
  43         str     r0, [sp, #S_R0+S_OFF]!          @ returned r0
  44 work_pending:
  45         tst     r1, #_TIF_NEED_RESCHED
  46         bne     work_resched
  47         tst     r1, #_TIF_SIGPENDING
  48         beq     no_work_pending
  49         mov     r0, sp                          @ 'regs'
  50         mov     r2, why                         @ 'syscall'
  51         bl      do_notify_resume
  52         b       ret_slow_syscall                @ Check work again
  53
  54 work_resched:
  55         bl      schedule
  56 /*
  57  * "slow" syscall return path.  "why" tells us if this was a real syscall.
  58  */
  59 ENTRY(ret_to_user)
  60 ret_slow_syscall:
  61         disable_irq                             @ disable interrupts
  62         ldr     r1, [tsk, #TI_FLAGS]
  63         tst     r1, #_TIF_WORK_MASK
  64         bne     work_pending
  65 no_work_pending:
  66         /* perform architecture specific actions before user return */
  67         arch_ret_to_user r1, lr
  68
  69         restore_user_regs fast = 0, offset = 0
  70 ENDPROC(ret_to_user)
  71
  72 /*
  73  * This is how we return from a fork.
  74  */
  75 ENTRY(ret_from_fork)
  76         bl      schedule_tail
  77         get_thread_info tsk
  78         ldr     r1, [tsk, #TI_FLAGS]            @ check for syscall tracing
  79         mov     why, #1
  80         tst     r1, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
  81         beq     ret_slow_syscall
  82         mov     r1, sp
  83         mov     r0, #1                          @ trace exit [IP = 1]
  84         bl      syscall_trace
  85         b       ret_slow_syscall
  86 ENDPROC(ret_from_fork)
  87
  88         .equ NR_syscalls,0
  89 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
  90 #include "calls.S"
  91 #undef CALL
  92 #define CALL(x) .long x
  93
  94 #ifdef CONFIG_FUNCTION_TRACER
  95 #ifdef CONFIG_DYNAMIC_FTRACE
  96 ENTRY(mcount)
  97         stmdb sp!, {r0-r3, lr}
  98         mov r0, lr
  99         sub r0, r0, #MCOUNT_INSN_SIZE
 100
 101         .globl mcount_call
 102 mcount_call:
 103         bl ftrace_stub
 104         ldr lr, [fp, #-4]                       @ restore lr
 105         ldmia sp!, {r0-r3, pc}
 106
 107 ENTRY(ftrace_caller)
 108         stmdb sp!, {r0-r3, lr}
 109         ldr r1, [fp, #-4]
 110         mov r0, lr
 111         sub r0, r0, #MCOUNT_INSN_SIZE
 112
 113         .globl ftrace_call
 114 ftrace_call:
 115         bl ftrace_stub
 116         ldr lr, [fp, #-4]                       @ restore lr
 117         ldmia sp!, {r0-r3, pc}
 118
 119 #else
 120
 121 ENTRY(mcount)
 122         stmdb sp!, {r0-r3, lr}
 123         ldr r0, =ftrace_trace_function
 124         ldr r2, [r0]
 125         adr r0, ftrace_stub
 126         cmp r0, r2
 127         bne trace
 128         ldr lr, [fp, #-4]                       @ restore lr
 129         ldmia sp!, {r0-r3, pc}
 130
 131 trace:
 132         ldr r1, [fp, #-4]                       @ lr of instrumented routine
 133         mov r0, lr
 134         sub r0, r0, #MCOUNT_INSN_SIZE
 135         mov lr, pc
 136         mov pc, r2
 137         mov lr, r1                              @ restore lr
 138         ldmia sp!, {r0-r3, pc}
 139
 140 #endif /* CONFIG_DYNAMIC_FTRACE */
 141
 142         .globl ftrace_stub
 143 ftrace_stub:
 144         mov pc, lr
 145
 146 #endif /* CONFIG_FUNCTION_TRACER */
 147
 148 /*=============================================================================
 149  * SWI handler
 150  *-----------------------------------------------------------------------------
 151  */
 152
 153         /* If we're optimising for StrongARM the resulting code won't
 154            run on an ARM7 and we can save a couple of instructions.
 155                                                                 --pb */
 156 #ifdef CONFIG_CPU_ARM710
 157 #define A710(code...) code
 158 .Larm710bug:
 159         ldmia   sp, {r0 - lr}^                  @ Get calling r0 - lr
 160         mov     r0, r0
 161         add     sp, sp, #S_FRAME_SIZE
 162         subs    pc, lr, #4
 163 #else
 164 #define A710(code...)
 165 #endif
 166
 167         .align  5
 168 ENTRY(vector_swi)
 169         sub     sp, sp, #S_FRAME_SIZE
 170         stmia   sp, {r0 - r12}                  @ Calling r0 - r12
 171  ARM(   add     r8, sp, #S_PC           )
 172  ARM(   stmdb   r8, {sp, lr}^           )       @ Calling sp, lr
 173  THUMB( mov     r8, sp                  )
 174  THUMB( store_user_sp_lr r8, r10, S_SP  )       @ calling sp, lr
 175         mrs     r8, spsr                        @ called from non-FIQ mode, so ok.
 176         str     lr, [sp, #S_PC]                 @ Save calling PC
 177         str     r8, [sp, #S_PSR]                @ Save CPSR
 178         str     r0, [sp, #S_OLD_R0]             @ Save OLD_R0
 179         zero_fp
 180
 181         /*
 182          * Get the system call number.
 183          */
 184
 185 #if defined(CONFIG_OABI_COMPAT)
 186
 187         /*
 188          * If we have CONFIG_OABI_COMPAT then we need to look at the swi
 189          * value to determine if it is an EABI or an old ABI call.
 190          */
 191 #ifdef CONFIG_ARM_THUMB
 192         tst     r8, #PSR_T_BIT
 193         movne   r10, #0                         @ no thumb OABI emulation
 194         ldreq   r10, [lr, #-4]                  @ get SWI instruction
 195 #else
 196         ldr     r10, [lr, #-4]                  @ get SWI instruction
 197   A710( and     ip, r10, #0x0f000000            @ check for SWI         )
 198   A710( teq     ip, #0x0f000000                                         )
 199   A710( bne     .Larm710bug                                             )
 200 #endif
 201 #ifdef CONFIG_CPU_ENDIAN_BE8
 202         rev     r10, r10                        @ little endian instruction
 203 #endif
 204
 205 #elif defined(CONFIG_AEABI)
 206
 207         /*
 208          * Pure EABI user space always put syscall number into scno (r7).
 209          */
 210   A710( ldr     ip, [lr, #-4]                   @ get SWI instruction   )
 211   A710( and     ip, ip, #0x0f000000             @ check for SWI         )
 212   A710( teq     ip, #0x0f000000                                         )
 213   A710( bne     .Larm710bug                                             )
 214
 215 #elif defined(CONFIG_ARM_THUMB)
 216
 217         /* Legacy ABI only, possibly thumb mode. */
 218         tst     r8, #PSR_T_BIT                  @ this is SPSR from save_user_regs
 219         addne   scno, r7, #__NR_SYSCALL_BASE    @ put OS number in
 220         ldreq   scno, [lr, #-4]
 221
 222 #else
 223
 224         /* Legacy ABI only. */
 225         ldr     scno, [lr, #-4]                 @ get SWI instruction
 226   A710( and     ip, scno, #0x0f000000           @ check for SWI         )
 227   A710( teq     ip, #0x0f000000                                         )
 228   A710( bne     .Larm710bug                                             )
 229
 230 #endif
 231
 232 #ifdef CONFIG_ALIGNMENT_TRAP
 233         ldr     ip, __cr_alignment
 234         ldr     ip, [ip]
 235         mcr     p15, 0, ip, c1, c0              @ update control register
 236 #endif
 237         enable_irq
 238
 239         get_thread_info tsk
 240         adr     tbl, sys_call_table             @ load syscall table pointer
 241         ldr     ip, [tsk, #TI_FLAGS]            @ check for syscall tracing
 242
 243 #if defined(CONFIG_OABI_COMPAT)
 244         /*
 245          * If the swi argument is zero, this is an EABI call and we do nothing.
 246          *
 247          * If this is an old ABI call, get the syscall number into scno and
 248          * get the old ABI syscall table address.
 249          */
 250         bics    r10, r10, #0xff000000
 251         eorne   scno, r10, #__NR_OABI_SYSCALL_BASE
 252         ldrne   tbl, =sys_oabi_call_table
 253 #elif !defined(CONFIG_AEABI)
 254         bic     scno, scno, #0xff000000         @ mask off SWI op-code
 255         eor     scno, scno, #__NR_SYSCALL_BASE  @ check OS number
 256 #endif
 257
 258         stmdb   sp!, {r4, r5}                   @ push fifth and sixth args
 259         tst     ip, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
 260         bne     __sys_trace
 261
 262         cmp     scno, #NR_syscalls              @ check upper syscall limit
 263         adr     lr, BSYM(ret_fast_syscall)      @ return address
 264         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 265
 266         add     r1, sp, #S_OFF
 267 2:      mov     why, #0                         @ no longer a real syscall
 268         cmp     scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
 269         eor     r0, scno, #__NR_SYSCALL_BASE    @ put OS number back
 270         bcs     arm_syscall
 271         b       sys_ni_syscall                  @ not private func
 272 ENDPROC(vector_swi)
 273
 274         /*
 275          * This is the really slow path.  We're going to be doing
 276          * context switches, and waiting for our parent to respond.
 277          */
 278 __sys_trace:
 279         mov     r2, scno
 280         add     r1, sp, #S_OFF
 281         mov     r0, #0                          @ trace entry [IP = 0]
 282         bl      syscall_trace
 283
 284         adr     lr, BSYM(__sys_trace_return)    @ return address
 285         mov     scno, r0                        @ syscall number (possibly new)
 286         add     r1, sp, #S_R0 + S_OFF           @ pointer to regs
 287         cmp     scno, #NR_syscalls              @ check upper syscall limit
 288         ldmccia r1, {r0 - r3}                   @ have to reload r0 - r3
 289         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 290         b       2b
 291
 292 __sys_trace_return:
 293         str     r0, [sp, #S_R0 + S_OFF]!        @ save returned r0
 294         mov     r2, scno
 295         mov     r1, sp
 296         mov     r0, #1                          @ trace exit [IP = 1]
 297         bl      syscall_trace
 298         b       ret_slow_syscall
 299
 300         .align  5
 301 #ifdef CONFIG_ALIGNMENT_TRAP
 302         .type   __cr_alignment, #object
 303 __cr_alignment:
 304         .word   cr_alignment
 305 #endif
 306         .ltorg
 307
 308 /*
 309  * This is the syscall table declaration for native ABI syscalls.
 310  * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
 311  */
 312 #define ABI(native, compat) native
 313 #ifdef CONFIG_AEABI
 314 #define OBSOLETE(syscall) sys_ni_syscall
 315 #else
 316 #define OBSOLETE(syscall) syscall
 317 #endif
 318
 319         .type   sys_call_table, #object
 320 ENTRY(sys_call_table)
 321 #include "calls.S"
 322 #undef ABI
 323 #undef OBSOLETE
 324
 325 /*============================================================================
 326  * Special system call wrappers
 327  */
 328 @ r0 = syscall number
 329 @ r8 = syscall table
 330 sys_syscall:
 331                 bic     scno, r0, #__NR_OABI_SYSCALL_BASE
 332                 cmp     scno, #__NR_syscall - __NR_SYSCALL_BASE
 333                 cmpne   scno, #NR_syscalls      @ check range
 334                 stmloia sp, {r5, r6}            @ shuffle args
 335                 movlo   r0, r1
 336                 movlo   r1, r2
 337                 movlo   r2, r3
 338                 movlo   r3, r4
 339                 ldrlo   pc, [tbl, scno, lsl #2]
 340                 b       sys_ni_syscall
 341 ENDPROC(sys_syscall)
 342
 343 sys_fork_wrapper:
 344                 add     r0, sp, #S_OFF
 345                 b       sys_fork
 346 ENDPROC(sys_fork_wrapper)
 347
 348 sys_vfork_wrapper:
 349                 add     r0, sp, #S_OFF
 350                 b       sys_vfork
 351 ENDPROC(sys_vfork_wrapper)
 352
 353 sys_execve_wrapper:
 354                 add     r3, sp, #S_OFF
 355                 b       sys_execve
 356 ENDPROC(sys_execve_wrapper)
 357
 358 sys_clone_wrapper:
 359                 add     ip, sp, #S_OFF
 360                 str     ip, [sp, #4]
 361                 b       sys_clone
 362 ENDPROC(sys_clone_wrapper)
 363
 364 sys_sigsuspend_wrapper:
 365                 add     r3, sp, #S_OFF
 366                 b       sys_sigsuspend
 367 ENDPROC(sys_sigsuspend_wrapper)
 368
 369 sys_rt_sigsuspend_wrapper:
 370                 add     r2, sp, #S_OFF
 371                 b       sys_rt_sigsuspend
 372 ENDPROC(sys_rt_sigsuspend_wrapper)
 373
 374 sys_sigreturn_wrapper:
 375                 add     r0, sp, #S_OFF
 376                 b       sys_sigreturn
 377 ENDPROC(sys_sigreturn_wrapper)
 378
 379 sys_rt_sigreturn_wrapper:
 380                 add     r0, sp, #S_OFF
 381                 b       sys_rt_sigreturn
 382 ENDPROC(sys_rt_sigreturn_wrapper)
 383
 384 sys_sigaltstack_wrapper:
 385                 ldr     r2, [sp, #S_OFF + S_SP]
 386                 b       do_sigaltstack
 387 ENDPROC(sys_sigaltstack_wrapper)
 388
 389 sys_statfs64_wrapper:
 390                 teq     r1, #88
 391                 moveq   r1, #84
 392                 b       sys_statfs64
 393 ENDPROC(sys_statfs64_wrapper)
 394
 395 sys_fstatfs64_wrapper:
 396                 teq     r1, #88
 397                 moveq   r1, #84
 398                 b       sys_fstatfs64
 399 ENDPROC(sys_fstatfs64_wrapper)
 400
 401 /*
 402  * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
 403  * offset, we return EINVAL.
 404  */
 405 sys_mmap2:
 406 #if PAGE_SHIFT > 12
 407                 tst     r5, #PGOFF_MASK
 408                 moveq   r5, r5, lsr #PAGE_SHIFT - 12
 409                 streq   r5, [sp, #4]
 410                 beq     do_mmap2
 411                 mov     r0, #-EINVAL
 412                 mov     pc, lr
 413 #else
 414                 str     r5, [sp, #4]
 415                 b       do_mmap2
 416 #endif
 417 ENDPROC(sys_mmap2)
 418
 419 ENTRY(pabort_ifar)
 420                 mrc     p15, 0, r0, cr6, cr0, 2
 421 ENTRY(pabort_noifar)
 422                 mov     pc, lr
 423 ENDPROC(pabort_ifar)
 424 ENDPROC(pabort_noifar)
 425
 426 #ifdef CONFIG_OABI_COMPAT
 427
 428 /*
 429  * These are syscalls with argument register differences
 430  */
 431
 432 sys_oabi_pread64:
 433                 stmia   sp, {r3, r4}
 434                 b       sys_pread64
 435 ENDPROC(sys_oabi_pread64)
 436
 437 sys_oabi_pwrite64:
 438                 stmia   sp, {r3, r4}
 439                 b       sys_pwrite64
 440 ENDPROC(sys_oabi_pwrite64)
 441
 442 sys_oabi_truncate64:
 443                 mov     r3, r2
 444                 mov     r2, r1
 445                 b       sys_truncate64
 446 ENDPROC(sys_oabi_truncate64)
 447
 448 sys_oabi_ftruncate64:
 449                 mov     r3, r2
 450                 mov     r2, r1
 451                 b       sys_ftruncate64
 452 ENDPROC(sys_oabi_ftruncate64)
 453
 454 sys_oabi_readahead:
 455                 str     r3, [sp]
 456                 mov     r3, r2
 457                 mov     r2, r1
 458                 b       sys_readahead
 459 ENDPROC(sys_oabi_readahead)
 460
 461 /*
 462  * Let's declare a second syscall table for old ABI binaries
 463  * using the compatibility syscall entries.
 464  */
 465 #define ABI(native, compat) compat
 466 #define OBSOLETE(syscall) syscall
 467
 468         .type   sys_oabi_call_table, #object
 469 ENTRY(sys_oabi_call_table)
 470 #include "calls.S"
 471 #undef ABI
 472 #undef OBSOLETE
 473
 474 #endif
 475