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