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
  15 #include "entry-header.S"
  16
  17
  18         .align  5
  19 /*
  20  * This is the fast syscall return path.  We do as little as
  21  * possible here, and this includes saving r0 back into the SVC
  22  * stack.
  23  */
  24 ret_fast_syscall:
  25         disable_irq                             @ disable interrupts
  26         ldr     r1, [tsk, #TI_FLAGS]
  27         tst     r1, #_TIF_WORK_MASK
  28         bne     fast_work_pending
  29
  30         /* perform architecture specific actions before user return */
  31         arch_ret_to_user r1, lr
  32
  33         @ fast_restore_user_regs
  34         ldr     r1, [sp, #S_OFF + S_PSR]        @ get calling cpsr
  35         ldr     lr, [sp, #S_OFF + S_PC]!        @ get pc
  36         msr     spsr_cxsf, r1                   @ save in spsr_svc
  37         ldmdb   sp, {r1 - lr}^                  @ get calling r1 - lr
  38         mov     r0, r0
  39         add     sp, sp, #S_FRAME_SIZE - S_PC
  40         movs    pc, lr                          @ return & move spsr_svc into cpsr
  41
  42 /*
  43  * Ok, we need to do extra processing, enter the slow path.
  44  */
  45 fast_work_pending:
  46         str     r0, [sp, #S_R0+S_OFF]!          @ returned r0
  47 work_pending:
  48         tst     r1, #_TIF_NEED_RESCHED
  49         bne     work_resched
  50         tst     r1, #_TIF_SIGPENDING
  51         beq     no_work_pending
  52         mov     r0, sp                          @ 'regs'
  53         mov     r2, why                         @ 'syscall'
  54         bl      do_notify_resume
  55         b       ret_slow_syscall                @ Check work again
  56
  57 work_resched:
  58         bl      schedule
  59 /*
  60  * "slow" syscall return path.  "why" tells us if this was a real syscall.
  61  */
  62 ENTRY(ret_to_user)
  63 ret_slow_syscall:
  64         disable_irq                             @ disable interrupts
  65         ldr     r1, [tsk, #TI_FLAGS]
  66         tst     r1, #_TIF_WORK_MASK
  67         bne     work_pending
  68 no_work_pending:
  69         /* perform architecture specific actions before user return */
  70         arch_ret_to_user r1, lr
  71
  72         @ slow_restore_user_regs
  73         ldr     r1, [sp, #S_PSR]                @ get calling cpsr
  74         ldr     lr, [sp, #S_PC]!                @ get pc
  75         msr     spsr_cxsf, r1                   @ save in spsr_svc
  76         ldmdb   sp, {r0 - lr}^                  @ get calling r0 - lr
  77         mov     r0, r0
  78         add     sp, sp, #S_FRAME_SIZE - S_PC
  79         movs    pc, lr                          @ return & move spsr_svc into cpsr
  80 ENDPROC(ret_to_user)
  81
  82 /*
  83  * This is how we return from a fork.
  84  */
  85 ENTRY(ret_from_fork)
  86         bl      schedule_tail
  87         get_thread_info tsk
  88         ldr     r1, [tsk, #TI_FLAGS]            @ check for syscall tracing
  89         mov     why, #1
  90         tst     r1, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
  91         beq     ret_slow_syscall
  92         mov     r1, sp
  93         mov     r0, #1                          @ trace exit [IP = 1]
  94         bl      syscall_trace
  95         b       ret_slow_syscall
  96 ENDPROC(ret_from_fork)
  97
  98         .equ NR_syscalls,0
  99 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
 100 #include "calls.S"
 101 #undef CALL
 102 #define CALL(x) .long x
 103
 104 #ifdef CONFIG_FUNCTION_TRACER
 105 #ifdef CONFIG_DYNAMIC_FTRACE
 106 ENTRY(mcount)
 107         stmdb sp!, {r0-r3, lr}
 108         mov r0, lr
 109         sub r0, r0, #MCOUNT_INSN_SIZE
 110
 111         .globl mcount_call
 112 mcount_call:
 113         bl ftrace_stub
 114         ldmia sp!, {r0-r3, pc}
 115
 116 ENTRY(ftrace_caller)
 117         stmdb sp!, {r0-r3, lr}
 118         ldr r1, [fp, #-4]
 119         mov r0, lr
 120         sub r0, r0, #MCOUNT_INSN_SIZE
 121
 122         .globl ftrace_call
 123 ftrace_call:
 124         bl ftrace_stub
 125         ldmia sp!, {r0-r3, pc}
 126
 127 #else
 128
 129 ENTRY(mcount)
 130         stmdb sp!, {r0-r3, lr}
 131         ldr r0, =ftrace_trace_function
 132         ldr r2, [r0]
 133         adr r0, ftrace_stub
 134         cmp r0, r2
 135         bne trace
 136         ldmia sp!, {r0-r3, pc}
 137
 138 trace:
 139         ldr r1, [fp, #-4]
 140         mov r0, lr
 141         sub r0, r0, #MCOUNT_INSN_SIZE
 142         mov lr, pc
 143         mov pc, r2
 144         ldmia sp!, {r0-r3, pc}
 145
 146 #endif /* CONFIG_DYNAMIC_FTRACE */
 147
 148         .globl ftrace_stub
 149 ftrace_stub:
 150         mov pc, lr
 151
 152 #endif /* CONFIG_FUNCTION_TRACER */
 153
 154 /*=============================================================================
 155  * SWI handler
 156  *-----------------------------------------------------------------------------
 157  */
 158
 159         /* If we're optimising for StrongARM the resulting code won't
 160            run on an ARM7 and we can save a couple of instructions.
 161                                                                 --pb */
 162 #ifdef CONFIG_CPU_ARM710
 163 #define A710(code...) code
 164 .Larm710bug:
 165         ldmia   sp, {r0 - lr}^                  @ Get calling r0 - lr
 166         mov     r0, r0
 167         add     sp, sp, #S_FRAME_SIZE
 168         subs    pc, lr, #4
 169 #else
 170 #define A710(code...)
 171 #endif
 172
 173         .align  5
 174 ENTRY(vector_swi)
 175         sub     sp, sp, #S_FRAME_SIZE
 176         stmia   sp, {r0 - r12}                  @ Calling r0 - r12
 177         add     r8, sp, #S_PC
 178         stmdb   r8, {sp, lr}^                   @ Calling sp, lr
 179         mrs     r8, spsr                        @ called from non-FIQ mode, so ok.
 180         str     lr, [sp, #S_PC]                 @ Save calling PC
 181         str     r8, [sp, #S_PSR]                @ Save CPSR
 182         str     r0, [sp, #S_OLD_R0]             @ Save OLD_R0
 183         zero_fp
 184
 185         /*
 186          * Get the system call number.
 187          */
 188
 189 #if defined(CONFIG_OABI_COMPAT)
 190
 191         /*
 192          * If we have CONFIG_OABI_COMPAT then we need to look at the swi
 193          * value to determine if it is an EABI or an old ABI call.
 194          */
 195 #ifdef CONFIG_ARM_THUMB
 196         tst     r8, #PSR_T_BIT
 197         movne   r10, #0                         @ no thumb OABI emulation
 198         ldreq   r10, [lr, #-4]                  @ get SWI instruction
 199 #else
 200         ldr     r10, [lr, #-4]                  @ get SWI instruction
 201   A710( and     ip, r10, #0x0f000000            @ check for SWI         )
 202   A710( teq     ip, #0x0f000000                                         )
 203   A710( bne     .Larm710bug                                             )
 204 #endif
 205
 206 #elif defined(CONFIG_AEABI)
 207
 208         /*
 209          * Pure EABI user space always put syscall number into scno (r7).
 210          */
 211   A710( ldr     ip, [lr, #-4]                   @ get SWI instruction   )
 212   A710( and     ip, ip, #0x0f000000             @ check for SWI         )
 213   A710( teq     ip, #0x0f000000                                         )
 214   A710( bne     .Larm710bug                                             )
 215
 216 #elif defined(CONFIG_ARM_THUMB)
 217
 218         /* Legacy ABI only, possibly thumb mode. */
 219         tst     r8, #PSR_T_BIT                  @ this is SPSR from save_user_regs
 220         addne   scno, r7, #__NR_SYSCALL_BASE    @ put OS number in
 221         ldreq   scno, [lr, #-4]
 222
 223 #else
 224
 225         /* Legacy ABI only. */
 226         ldr     scno, [lr, #-4]                 @ get SWI instruction
 227   A710( and     ip, scno, #0x0f000000           @ check for SWI         )
 228   A710( teq     ip, #0x0f000000                                         )
 229   A710( bne     .Larm710bug                                             )
 230
 231 #endif
 232
 233 #ifdef CONFIG_ALIGNMENT_TRAP
 234         ldr     ip, __cr_alignment
 235         ldr     ip, [ip]
 236         mcr     p15, 0, ip, c1, c0              @ update control register
 237 #endif
 238         enable_irq
 239
 240         get_thread_info tsk
 241         adr     tbl, sys_call_table             @ load syscall table pointer
 242         ldr     ip, [tsk, #TI_FLAGS]            @ check for syscall tracing
 243
 244 #if defined(CONFIG_OABI_COMPAT)
 245         /*
 246          * If the swi argument is zero, this is an EABI call and we do nothing.
 247          *
 248          * If this is an old ABI call, get the syscall number into scno and
 249          * get the old ABI syscall table address.
 250          */
 251         bics    r10, r10, #0xff000000
 252         eorne   scno, r10, #__NR_OABI_SYSCALL_BASE
 253         ldrne   tbl, =sys_oabi_call_table
 254 #elif !defined(CONFIG_AEABI)
 255         bic     scno, scno, #0xff000000         @ mask off SWI op-code
 256         eor     scno, scno, #__NR_SYSCALL_BASE  @ check OS number
 257 #endif
 258
 259         stmdb   sp!, {r4, r5}                   @ push fifth and sixth args
 260         tst     ip, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
 261         bne     __sys_trace
 262
 263         cmp     scno, #NR_syscalls              @ check upper syscall limit
 264         adr     lr, ret_fast_syscall            @ return address
 265         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 266
 267         add     r1, sp, #S_OFF
 268 2:      mov     why, #0                         @ no longer a real syscall
 269         cmp     scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
 270         eor     r0, scno, #__NR_SYSCALL_BASE    @ put OS number back
 271         bcs     arm_syscall
 272         b       sys_ni_syscall                  @ not private func
 273 ENDPROC(vector_swi)
 274
 275         /*
 276          * This is the really slow path.  We're going to be doing
 277          * context switches, and waiting for our parent to respond.
 278          */
 279 __sys_trace:
 280         mov     r2, scno
 281         add     r1, sp, #S_OFF
 282         mov     r0, #0                          @ trace entry [IP = 0]
 283         bl      syscall_trace
 284
 285         adr     lr, __sys_trace_return          @ return address
 286         mov     scno, r0                        @ syscall number (possibly new)
 287         add     r1, sp, #S_R0 + S_OFF           @ pointer to regs
 288         cmp     scno, #NR_syscalls              @ check upper syscall limit
 289         ldmccia r1, {r0 - r3}                   @ have to reload r0 - r3
 290         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 291         b       2b
 292
 293 __sys_trace_return:
 294         str     r0, [sp, #S_R0 + S_OFF]!        @ save returned r0
 295         mov     r2, scno
 296         mov     r1, sp
 297         mov     r0, #1                          @ trace exit [IP = 1]
 298         bl      syscall_trace
 299         b       ret_slow_syscall
 300
 301         .align  5
 302 #ifdef CONFIG_ALIGNMENT_TRAP
 303         .type   __cr_alignment, #object
 304 __cr_alignment:
 305         .word   cr_alignment
 306 #endif
 307         .ltorg
 308
 309 /*
 310  * This is the syscall table declaration for native ABI syscalls.
 311  * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
 312  */
 313 #define ABI(native, compat) native
 314 #ifdef CONFIG_AEABI
 315 #define OBSOLETE(syscall) sys_ni_syscall
 316 #else
 317 #define OBSOLETE(syscall) syscall
 318 #endif
 319
 320         .type   sys_call_table, #object
 321 ENTRY(sys_call_table)
 322 #include "calls.S"
 323 #undef ABI
 324 #undef OBSOLETE
 325
 326 /*============================================================================
 327  * Special system call wrappers
 328  */
 329 @ r0 = syscall number
 330 @ r8 = syscall table
 331 sys_syscall:
 332                 bic     scno, r0, #__NR_OABI_SYSCALL_BASE
 333                 cmp     scno, #__NR_syscall - __NR_SYSCALL_BASE
 334                 cmpne   scno, #NR_syscalls      @ check range
 335                 stmloia sp, {r5, r6}            @ shuffle args
 336                 movlo   r0, r1
 337                 movlo   r1, r2
 338                 movlo   r2, r3
 339                 movlo   r3, r4
 340                 ldrlo   pc, [tbl, scno, lsl #2]
 341                 b       sys_ni_syscall
 342 ENDPROC(sys_syscall)
 343
 344 sys_fork_wrapper:
 345                 add     r0, sp, #S_OFF
 346                 b       sys_fork
 347 ENDPROC(sys_fork_wrapper)
 348
 349 sys_vfork_wrapper:
 350                 add     r0, sp, #S_OFF
 351                 b       sys_vfork
 352 ENDPROC(sys_vfork_wrapper)
 353
 354 sys_execve_wrapper:
 355                 add     r3, sp, #S_OFF
 356                 b       sys_execve
 357 ENDPROC(sys_execve_wrapper)
 358
 359 sys_clone_wrapper:
 360                 add     ip, sp, #S_OFF
 361                 str     ip, [sp, #4]
 362                 b       sys_clone
 363 ENDPROC(sys_clone_wrapper)
 364
 365 sys_sigsuspend_wrapper:
 366                 add     r3, sp, #S_OFF
 367                 b       sys_sigsuspend
 368 ENDPROC(sys_sigsuspend_wrapper)
 369
 370 sys_rt_sigsuspend_wrapper:
 371                 add     r2, sp, #S_OFF
 372                 b       sys_rt_sigsuspend
 373 ENDPROC(sys_rt_sigsuspend_wrapper)
 374
 375 sys_sigreturn_wrapper:
 376                 add     r0, sp, #S_OFF
 377                 b       sys_sigreturn
 378 ENDPROC(sys_sigreturn_wrapper)
 379
 380 sys_rt_sigreturn_wrapper:
 381                 add     r0, sp, #S_OFF
 382                 b       sys_rt_sigreturn
 383 ENDPROC(sys_rt_sigreturn_wrapper)
 384
 385 sys_sigaltstack_wrapper:
 386                 ldr     r2, [sp, #S_OFF + S_SP]
 387                 b       do_sigaltstack
 388 ENDPROC(sys_sigaltstack_wrapper)
 389
 390 sys_statfs64_wrapper:
 391                 teq     r1, #88
 392                 moveq   r1, #84
 393                 b       sys_statfs64
 394 ENDPROC(sys_statfs64_wrapper)
 395
 396 sys_fstatfs64_wrapper:
 397                 teq     r1, #88
 398                 moveq   r1, #84
 399                 b       sys_fstatfs64
 400 ENDPROC(sys_fstatfs64_wrapper)
 401
 402 /*
 403  * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
 404  * offset, we return EINVAL.
 405  */
 406 sys_mmap2:
 407 #if PAGE_SHIFT > 12
 408                 tst     r5, #PGOFF_MASK
 409                 moveq   r5, r5, lsr #PAGE_SHIFT - 12
 410                 streq   r5, [sp, #4]
 411                 beq     do_mmap2
 412                 mov     r0, #-EINVAL
 413                 mov     pc, lr
 414 #else
 415                 str     r5, [sp, #4]
 416                 b       do_mmap2
 417 #endif
 418 ENDPROC(sys_mmap2)
 419
 420 ENTRY(pabort_ifar)
 421                 mrc     p15, 0, r0, cr6, cr0, 2
 422 ENTRY(pabort_noifar)
 423                 mov     pc, lr
 424 ENDPROC(pabort_ifar)
 425 ENDPROC(pabort_noifar)
 426
 427 #ifdef CONFIG_OABI_COMPAT
 428
 429 /*
 430  * These are syscalls with argument register differences
 431  */
 432
 433 sys_oabi_pread64:
 434                 stmia   sp, {r3, r4}
 435                 b       sys_pread64
 436 ENDPROC(sys_oabi_pread64)
 437
 438 sys_oabi_pwrite64:
 439                 stmia   sp, {r3, r4}
 440                 b       sys_pwrite64
 441 ENDPROC(sys_oabi_pwrite64)
 442
 443 sys_oabi_truncate64:
 444                 mov     r3, r2
 445                 mov     r2, r1
 446                 b       sys_truncate64
 447 ENDPROC(sys_oabi_truncate64)
 448
 449 sys_oabi_ftruncate64:
 450                 mov     r3, r2
 451                 mov     r2, r1
 452                 b       sys_ftruncate64
 453 ENDPROC(sys_oabi_ftruncate64)
 454
 455 sys_oabi_readahead:
 456                 str     r3, [sp]
 457                 mov     r3, r2
 458                 mov     r2, r1
 459                 b       sys_readahead
 460 ENDPROC(sys_oabi_readahead)
 461
 462 /*
 463  * Let's declare a second syscall table for old ABI binaries
 464  * using the compatibility syscall entries.
 465  */
 466 #define ABI(native, compat) compat
 467 #define OBSOLETE(syscall) syscall
 468
 469         .type   sys_oabi_call_table, #object
 470 ENTRY(sys_oabi_call_table)
 471 #include "calls.S"
 472 #undef ABI
 473 #undef OBSOLETE
 474
 475 #endif
 476