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         @ fast_restore_user_regs
  37         ldr     r1, [sp, #S_OFF + S_PSR]        @ get calling cpsr
  38         ldr     lr, [sp, #S_OFF + S_PC]!        @ get pc
  39         msr     spsr_cxsf, r1                   @ save in spsr_svc
  40         ldmdb   sp, {r1 - lr}^                  @ get calling r1 - lr
  41         mov     r0, r0
  42         add     sp, sp, #S_FRAME_SIZE - S_PC
  43         movs    pc, lr                          @ return & move spsr_svc into cpsr
  44  UNWIND(.fnend          )
  45
  46 /*
  47  * Ok, we need to do extra processing, enter the slow path.
  48  */
  49 fast_work_pending:
  50         str     r0, [sp, #S_R0+S_OFF]!          @ returned r0
  51 work_pending:
  52         tst     r1, #_TIF_NEED_RESCHED
  53         bne     work_resched
  54         tst     r1, #_TIF_SIGPENDING
  55         beq     no_work_pending
  56         mov     r0, sp                          @ 'regs'
  57         mov     r2, why                         @ 'syscall'
  58         bl      do_notify_resume
  59         b       ret_slow_syscall                @ Check work again
  60
  61 work_resched:
  62         bl      schedule
  63 /*
  64  * "slow" syscall return path.  "why" tells us if this was a real syscall.
  65  */
  66 ENTRY(ret_to_user)
  67 ret_slow_syscall:
  68         disable_irq                             @ disable interrupts
  69         ldr     r1, [tsk, #TI_FLAGS]
  70         tst     r1, #_TIF_WORK_MASK
  71         bne     work_pending
  72 no_work_pending:
  73         /* perform architecture specific actions before user return */
  74         arch_ret_to_user r1, lr
  75
  76         @ slow_restore_user_regs
  77         ldr     r1, [sp, #S_PSR]                @ get calling cpsr
  78         ldr     lr, [sp, #S_PC]!                @ get pc
  79         msr     spsr_cxsf, r1                   @ save in spsr_svc
  80         ldmdb   sp, {r0 - lr}^                  @ get calling r0 - lr
  81         mov     r0, r0
  82         add     sp, sp, #S_FRAME_SIZE - S_PC
  83         movs    pc, lr                          @ return & move spsr_svc into cpsr
  84 ENDPROC(ret_to_user)
  85
  86 /*
  87  * This is how we return from a fork.
  88  */
  89 ENTRY(ret_from_fork)
  90         bl      schedule_tail
  91         get_thread_info tsk
  92         ldr     r1, [tsk, #TI_FLAGS]            @ check for syscall tracing
  93         mov     why, #1
  94         tst     r1, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
  95         beq     ret_slow_syscall
  96         mov     r1, sp
  97         mov     r0, #1                          @ trace exit [IP = 1]
  98         bl      syscall_trace
  99         b       ret_slow_syscall
 100 ENDPROC(ret_from_fork)
 101
 102         .equ NR_syscalls,0
 103 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
 104 #include "calls.S"
 105 #undef CALL
 106 #define CALL(x) .long x
 107
 108 #ifdef CONFIG_FUNCTION_TRACER
 109 #ifdef CONFIG_DYNAMIC_FTRACE
 110 ENTRY(mcount)
 111         stmdb sp!, {r0-r3, lr}
 112         mov r0, lr
 113         sub r0, r0, #MCOUNT_INSN_SIZE
 114
 115         .globl mcount_call
 116 mcount_call:
 117         bl ftrace_stub
 118         ldr lr, [fp, #-4]                       @ restore lr
 119         ldmia sp!, {r0-r3, pc}
 120
 121 ENTRY(ftrace_caller)
 122         stmdb sp!, {r0-r3, lr}
 123         ldr r1, [fp, #-4]
 124         mov r0, lr
 125         sub r0, r0, #MCOUNT_INSN_SIZE
 126
 127         .globl ftrace_call
 128 ftrace_call:
 129         bl ftrace_stub
 130         ldr lr, [fp, #-4]                       @ restore lr
 131         ldmia sp!, {r0-r3, pc}
 132
 133 #else
 134
 135 ENTRY(mcount)
 136         stmdb sp!, {r0-r3, lr}
 137         ldr r0, =ftrace_trace_function
 138         ldr r2, [r0]
 139         adr r0, ftrace_stub
 140         cmp r0, r2
 141         bne trace
 142         ldr lr, [fp, #-4]                       @ restore lr
 143         ldmia sp!, {r0-r3, pc}
 144
 145 trace:
 146         ldr r1, [fp, #-4]                       @ lr of instrumented routine
 147         mov r0, lr
 148         sub r0, r0, #MCOUNT_INSN_SIZE
 149         mov lr, pc
 150         mov pc, r2
 151         mov lr, r1                              @ restore lr
 152         ldmia sp!, {r0-r3, pc}
 153
 154 #endif /* CONFIG_DYNAMIC_FTRACE */
 155
 156         .globl ftrace_stub
 157 ftrace_stub:
 158         mov pc, lr
 159
 160 #endif /* CONFIG_FUNCTION_TRACER */
 161
 162 /*=============================================================================
 163  * SWI handler
 164  *-----------------------------------------------------------------------------
 165  */
 166
 167         /* If we're optimising for StrongARM the resulting code won't
 168            run on an ARM7 and we can save a couple of instructions.
 169                                                                 --pb */
 170 #ifdef CONFIG_CPU_ARM710
 171 #define A710(code...) code
 172 .Larm710bug:
 173         ldmia   sp, {r0 - lr}^                  @ Get calling r0 - lr
 174         mov     r0, r0
 175         add     sp, sp, #S_FRAME_SIZE
 176         subs    pc, lr, #4
 177 #else
 178 #define A710(code...)
 179 #endif
 180
 181         .align  5
 182 ENTRY(vector_swi)
 183         sub     sp, sp, #S_FRAME_SIZE
 184         stmia   sp, {r0 - r12}                  @ Calling r0 - r12
 185         add     r8, sp, #S_PC
 186         stmdb   r8, {sp, lr}^                   @ Calling sp, lr
 187         mrs     r8, spsr                        @ called from non-FIQ mode, so ok.
 188         str     lr, [sp, #S_PC]                 @ Save calling PC
 189         str     r8, [sp, #S_PSR]                @ Save CPSR
 190         str     r0, [sp, #S_OLD_R0]             @ Save OLD_R0
 191         zero_fp
 192
 193         /*
 194          * Get the system call number.
 195          */
 196
 197 #if defined(CONFIG_OABI_COMPAT)
 198
 199         /*
 200          * If we have CONFIG_OABI_COMPAT then we need to look at the swi
 201          * value to determine if it is an EABI or an old ABI call.
 202          */
 203 #ifdef CONFIG_ARM_THUMB
 204         tst     r8, #PSR_T_BIT
 205         movne   r10, #0                         @ no thumb OABI emulation
 206         ldreq   r10, [lr, #-4]                  @ get SWI instruction
 207 #else
 208         ldr     r10, [lr, #-4]                  @ get SWI instruction
 209   A710( and     ip, r10, #0x0f000000            @ check for SWI         )
 210   A710( teq     ip, #0x0f000000                                         )
 211   A710( bne     .Larm710bug                                             )
 212 #endif
 213 #ifdef CONFIG_CPU_ENDIAN_BE8
 214         rev     r10, r10                        @ little endian instruction
 215 #endif
 216
 217 #elif defined(CONFIG_AEABI)
 218
 219         /*
 220          * Pure EABI user space always put syscall number into scno (r7).
 221          */
 222   A710( ldr     ip, [lr, #-4]                   @ get SWI instruction   )
 223   A710( and     ip, ip, #0x0f000000             @ check for SWI         )
 224   A710( teq     ip, #0x0f000000                                         )
 225   A710( bne     .Larm710bug                                             )
 226
 227 #elif defined(CONFIG_ARM_THUMB)
 228
 229         /* Legacy ABI only, possibly thumb mode. */
 230         tst     r8, #PSR_T_BIT                  @ this is SPSR from save_user_regs
 231         addne   scno, r7, #__NR_SYSCALL_BASE    @ put OS number in
 232         ldreq   scno, [lr, #-4]
 233
 234 #else
 235
 236         /* Legacy ABI only. */
 237         ldr     scno, [lr, #-4]                 @ get SWI instruction
 238   A710( and     ip, scno, #0x0f000000           @ check for SWI         )
 239   A710( teq     ip, #0x0f000000                                         )
 240   A710( bne     .Larm710bug                                             )
 241
 242 #endif
 243
 244 #ifdef CONFIG_ALIGNMENT_TRAP
 245         ldr     ip, __cr_alignment
 246         ldr     ip, [ip]
 247         mcr     p15, 0, ip, c1, c0              @ update control register
 248 #endif
 249         enable_irq
 250
 251         get_thread_info tsk
 252         adr     tbl, sys_call_table             @ load syscall table pointer
 253         ldr     ip, [tsk, #TI_FLAGS]            @ check for syscall tracing
 254
 255 #if defined(CONFIG_OABI_COMPAT)
 256         /*
 257          * If the swi argument is zero, this is an EABI call and we do nothing.
 258          *
 259          * If this is an old ABI call, get the syscall number into scno and
 260          * get the old ABI syscall table address.
 261          */
 262         bics    r10, r10, #0xff000000
 263         eorne   scno, r10, #__NR_OABI_SYSCALL_BASE
 264         ldrne   tbl, =sys_oabi_call_table
 265 #elif !defined(CONFIG_AEABI)
 266         bic     scno, scno, #0xff000000         @ mask off SWI op-code
 267         eor     scno, scno, #__NR_SYSCALL_BASE  @ check OS number
 268 #endif
 269
 270         stmdb   sp!, {r4, r5}                   @ push fifth and sixth args
 271         tst     ip, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
 272         bne     __sys_trace
 273
 274         cmp     scno, #NR_syscalls              @ check upper syscall limit
 275         adr     lr, ret_fast_syscall            @ return address
 276         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 277
 278         add     r1, sp, #S_OFF
 279 2:      mov     why, #0                         @ no longer a real syscall
 280         cmp     scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
 281         eor     r0, scno, #__NR_SYSCALL_BASE    @ put OS number back
 282         bcs     arm_syscall
 283         b       sys_ni_syscall                  @ not private func
 284 ENDPROC(vector_swi)
 285
 286         /*
 287          * This is the really slow path.  We're going to be doing
 288          * context switches, and waiting for our parent to respond.
 289          */
 290 __sys_trace:
 291         mov     r2, scno
 292         add     r1, sp, #S_OFF
 293         mov     r0, #0                          @ trace entry [IP = 0]
 294         bl      syscall_trace
 295
 296         adr     lr, __sys_trace_return          @ return address
 297         mov     scno, r0                        @ syscall number (possibly new)
 298         add     r1, sp, #S_R0 + S_OFF           @ pointer to regs
 299         cmp     scno, #NR_syscalls              @ check upper syscall limit
 300         ldmccia r1, {r0 - r3}                   @ have to reload r0 - r3
 301         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 302         b       2b
 303
 304 __sys_trace_return:
 305         str     r0, [sp, #S_R0 + S_OFF]!        @ save returned r0
 306         mov     r2, scno
 307         mov     r1, sp
 308         mov     r0, #1                          @ trace exit [IP = 1]
 309         bl      syscall_trace
 310         b       ret_slow_syscall
 311
 312         .align  5
 313 #ifdef CONFIG_ALIGNMENT_TRAP
 314         .type   __cr_alignment, #object
 315 __cr_alignment:
 316         .word   cr_alignment
 317 #endif
 318         .ltorg
 319
 320 /*
 321  * This is the syscall table declaration for native ABI syscalls.
 322  * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
 323  */
 324 #define ABI(native, compat) native
 325 #ifdef CONFIG_AEABI
 326 #define OBSOLETE(syscall) sys_ni_syscall
 327 #else
 328 #define OBSOLETE(syscall) syscall
 329 #endif
 330
 331         .type   sys_call_table, #object
 332 ENTRY(sys_call_table)
 333 #include "calls.S"
 334 #undef ABI
 335 #undef OBSOLETE
 336
 337 /*============================================================================
 338  * Special system call wrappers
 339  */
 340 @ r0 = syscall number
 341 @ r8 = syscall table
 342 sys_syscall:
 343                 bic     scno, r0, #__NR_OABI_SYSCALL_BASE
 344                 cmp     scno, #__NR_syscall - __NR_SYSCALL_BASE
 345                 cmpne   scno, #NR_syscalls      @ check range
 346                 stmloia sp, {r5, r6}            @ shuffle args
 347                 movlo   r0, r1
 348                 movlo   r1, r2
 349                 movlo   r2, r3
 350                 movlo   r3, r4
 351                 ldrlo   pc, [tbl, scno, lsl #2]
 352                 b       sys_ni_syscall
 353 ENDPROC(sys_syscall)
 354
 355 sys_fork_wrapper:
 356                 add     r0, sp, #S_OFF
 357                 b       sys_fork
 358 ENDPROC(sys_fork_wrapper)
 359
 360 sys_vfork_wrapper:
 361                 add     r0, sp, #S_OFF
 362                 b       sys_vfork
 363 ENDPROC(sys_vfork_wrapper)
 364
 365 sys_execve_wrapper:
 366                 add     r3, sp, #S_OFF
 367                 b       sys_execve
 368 ENDPROC(sys_execve_wrapper)
 369
 370 sys_clone_wrapper:
 371                 add     ip, sp, #S_OFF
 372                 str     ip, [sp, #4]
 373                 b       sys_clone
 374 ENDPROC(sys_clone_wrapper)
 375
 376 sys_sigsuspend_wrapper:
 377                 add     r3, sp, #S_OFF
 378                 b       sys_sigsuspend
 379 ENDPROC(sys_sigsuspend_wrapper)
 380
 381 sys_rt_sigsuspend_wrapper:
 382                 add     r2, sp, #S_OFF
 383                 b       sys_rt_sigsuspend
 384 ENDPROC(sys_rt_sigsuspend_wrapper)
 385
 386 sys_sigreturn_wrapper:
 387                 add     r0, sp, #S_OFF
 388                 b       sys_sigreturn
 389 ENDPROC(sys_sigreturn_wrapper)
 390
 391 sys_rt_sigreturn_wrapper:
 392                 add     r0, sp, #S_OFF
 393                 b       sys_rt_sigreturn
 394 ENDPROC(sys_rt_sigreturn_wrapper)
 395
 396 sys_sigaltstack_wrapper:
 397                 ldr     r2, [sp, #S_OFF + S_SP]
 398                 b       do_sigaltstack
 399 ENDPROC(sys_sigaltstack_wrapper)
 400
 401 sys_statfs64_wrapper:
 402                 teq     r1, #88
 403                 moveq   r1, #84
 404                 b       sys_statfs64
 405 ENDPROC(sys_statfs64_wrapper)
 406
 407 sys_fstatfs64_wrapper:
 408                 teq     r1, #88
 409                 moveq   r1, #84
 410                 b       sys_fstatfs64
 411 ENDPROC(sys_fstatfs64_wrapper)
 412
 413 /*
 414  * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
 415  * offset, we return EINVAL.
 416  */
 417 sys_mmap2:
 418 #if PAGE_SHIFT > 12
 419                 tst     r5, #PGOFF_MASK
 420                 moveq   r5, r5, lsr #PAGE_SHIFT - 12
 421                 streq   r5, [sp, #4]
 422                 beq     do_mmap2
 423                 mov     r0, #-EINVAL
 424                 mov     pc, lr
 425 #else
 426                 str     r5, [sp, #4]
 427                 b       do_mmap2
 428 #endif
 429 ENDPROC(sys_mmap2)
 430
 431 ENTRY(pabort_ifar)
 432                 mrc     p15, 0, r0, cr6, cr0, 2
 433 ENTRY(pabort_noifar)
 434                 mov     pc, lr
 435 ENDPROC(pabort_ifar)
 436 ENDPROC(pabort_noifar)
 437
 438 #ifdef CONFIG_OABI_COMPAT
 439
 440 /*
 441  * These are syscalls with argument register differences
 442  */
 443
 444 sys_oabi_pread64:
 445                 stmia   sp, {r3, r4}
 446                 b       sys_pread64
 447 ENDPROC(sys_oabi_pread64)
 448
 449 sys_oabi_pwrite64:
 450                 stmia   sp, {r3, r4}
 451                 b       sys_pwrite64
 452 ENDPROC(sys_oabi_pwrite64)
 453
 454 sys_oabi_truncate64:
 455                 mov     r3, r2
 456                 mov     r2, r1
 457                 b       sys_truncate64
 458 ENDPROC(sys_oabi_truncate64)
 459
 460 sys_oabi_ftruncate64:
 461                 mov     r3, r2
 462                 mov     r2, r1
 463                 b       sys_ftruncate64
 464 ENDPROC(sys_oabi_ftruncate64)
 465
 466 sys_oabi_readahead:
 467                 str     r3, [sp]
 468                 mov     r3, r2
 469                 mov     r2, r1
 470                 b       sys_readahead
 471 ENDPROC(sys_oabi_readahead)
 472
 473 /*
 474  * Let's declare a second syscall table for old ABI binaries
 475  * using the compatibility syscall entries.
 476  */
 477 #define ABI(native, compat) compat
 478 #define OBSOLETE(syscall) syscall
 479
 480         .type   sys_oabi_call_table, #object
 481 ENTRY(sys_oabi_call_table)
 482 #include "calls.S"
 483 #undef ABI
 484 #undef OBSOLETE
 485
 486 #endif
 487