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 #include <linux/config.h>
  11
  12 #include <asm/unistd.h>
  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         @ fast_restore_user_regs
  30         ldr     r1, [sp, #S_OFF + S_PSR]        @ get calling cpsr
  31         ldr     lr, [sp, #S_OFF + S_PC]!        @ get pc
  32         msr     spsr_cxsf, r1                   @ save in spsr_svc
  33         ldmdb   sp, {r1 - lr}^                  @ get calling r1 - lr
  34         mov     r0, r0
  35         add     sp, sp, #S_FRAME_SIZE - S_PC
  36         movs    pc, lr                          @ return & move spsr_svc into cpsr
  37
  38 /*
  39  * Ok, we need to do extra processing, enter the slow path.
  40  */
  41 fast_work_pending:
  42         str     r0, [sp, #S_R0+S_OFF]!          @ returned r0
  43 work_pending:
  44         tst     r1, #_TIF_NEED_RESCHED
  45         bne     work_resched
  46         tst     r1, #_TIF_NOTIFY_RESUME | _TIF_SIGPENDING
  47         beq     no_work_pending
  48         mov     r0, sp                          @ 'regs'
  49         mov     r2, why                         @ 'syscall'
  50         bl      do_notify_resume
  51         disable_irq                             @ disable interrupts
  52         b       no_work_pending
  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         @ slow_restore_user_regs
  67         ldr     r1, [sp, #S_PSR]                @ get calling cpsr
  68         ldr     lr, [sp, #S_PC]!                @ get pc
  69         msr     spsr_cxsf, r1                   @ save in spsr_svc
  70         ldmdb   sp, {r0 - lr}^                  @ get calling r1 - lr
  71         mov     r0, r0
  72         add     sp, sp, #S_FRAME_SIZE - S_PC
  73         movs    pc, lr                          @ return & move spsr_svc into cpsr
  74
  75 /*
  76  * This is how we return from a fork.
  77  */
  78 ENTRY(ret_from_fork)
  79         bl      schedule_tail
  80         get_thread_info tsk
  81         ldr     r1, [tsk, #TI_FLAGS]            @ check for syscall tracing
  82         mov     why, #1
  83         tst     r1, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
  84         beq     ret_slow_syscall
  85         mov     r1, sp
  86         mov     r0, #1                          @ trace exit [IP = 1]
  87         bl      syscall_trace
  88         b       ret_slow_syscall
  89
  90
  91 #include "calls.S"
  92
  93 /*=============================================================================
  94  * SWI handler
  95  *-----------------------------------------------------------------------------
  96  */
  97
  98         /* If we're optimising for StrongARM the resulting code won't
  99            run on an ARM7 and we can save a couple of instructions.
 100                                                                 --pb */
 101 #ifdef CONFIG_CPU_ARM710
 102         .macro  arm710_bug_check, instr, temp
 103         and     \temp, \instr, #0x0f000000      @ check for SWI
 104         teq     \temp, #0x0f000000
 105         bne     .Larm700bug
 106         .endm
 107
 108 .Larm700bug:
 109         ldr     r0, [sp, #S_PSR]                @ Get calling cpsr
 110         sub     lr, lr, #4
 111         str     lr, [r8]
 112         msr     spsr_cxsf, r0
 113         ldmia   sp, {r0 - lr}^                  @ Get calling r0 - lr
 114         mov     r0, r0
 115         ldr     lr, [sp, #S_PC]                 @ Get PC
 116         add     sp, sp, #S_FRAME_SIZE
 117         movs    pc, lr
 118 #else
 119         .macro  arm710_bug_check, instr, temp
 120         .endm
 121 #endif
 122
 123         .align  5
 124 ENTRY(vector_swi)
 125         sub     sp, sp, #S_FRAME_SIZE
 126         stmia   sp, {r0 - r12}                  @ Calling r0 - r12
 127         add     r8, sp, #S_PC
 128         stmdb   r8, {sp, lr}^                   @ Calling sp, lr
 129         mrs     r8, spsr                        @ called from non-FIQ mode, so ok.
 130         str     lr, [sp, #S_PC]                 @ Save calling PC
 131         str     r8, [sp, #S_PSR]                @ Save CPSR
 132         str     r0, [sp, #S_OLD_R0]             @ Save OLD_R0
 133         zero_fp
 134
 135         /*
 136          * Get the system call number.
 137          */
 138 #ifdef CONFIG_ARM_THUMB
 139         tst     r8, #PSR_T_BIT                  @ this is SPSR from save_user_regs
 140         addne   scno, r7, #__NR_SYSCALL_BASE    @ put OS number in
 141         ldreq   scno, [lr, #-4]
 142 #else
 143         ldr     scno, [lr, #-4]                 @ get SWI instruction
 144 #endif
 145         arm710_bug_check scno, ip
 146
 147 #ifdef CONFIG_ALIGNMENT_TRAP
 148         ldr     ip, __cr_alignment
 149         ldr     ip, [ip]
 150         mcr     p15, 0, ip, c1, c0              @ update control register
 151 #endif
 152         enable_irq
 153
 154         str     r4, [sp, #-S_OFF]!              @ push fifth arg
 155
 156         get_thread_info tsk
 157         ldr     ip, [tsk, #TI_FLAGS]            @ check for syscall tracing
 158         bic     scno, scno, #0xff000000         @ mask off SWI op-code
 159         eor     scno, scno, #__NR_SYSCALL_BASE  @ check OS number
 160         adr     tbl, sys_call_table             @ load syscall table pointer
 161         tst     ip, #_TIF_SYSCALL_TRACE         @ are we tracing syscalls?
 162         bne     __sys_trace
 163
 164         adr     lr, ret_fast_syscall            @ return address
 165         cmp     scno, #NR_syscalls              @ check upper syscall limit
 166         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 167
 168         add     r1, sp, #S_OFF
 169 2:      mov     why, #0                         @ no longer a real syscall
 170         cmp     scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
 171         eor     r0, scno, #__NR_SYSCALL_BASE    @ put OS number back
 172         bcs     arm_syscall
 173         b       sys_ni_syscall                  @ not private func
 174
 175         /*
 176          * This is the really slow path.  We're going to be doing
 177          * context switches, and waiting for our parent to respond.
 178          */
 179 __sys_trace:
 180         add     r1, sp, #S_OFF
 181         mov     r0, #0                          @ trace entry [IP = 0]
 182         bl      syscall_trace
 183
 184         adr     lr, __sys_trace_return          @ return address
 185         add     r1, sp, #S_R0 + S_OFF           @ pointer to regs
 186         cmp     scno, #NR_syscalls              @ check upper syscall limit
 187         ldmccia r1, {r0 - r3}                   @ have to reload r0 - r3
 188         ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
 189         b       2b
 190
 191 __sys_trace_return:
 192         str     r0, [sp, #S_R0 + S_OFF]!        @ save returned r0
 193         mov     r1, sp
 194         mov     r0, #1                          @ trace exit [IP = 1]
 195         bl      syscall_trace
 196         b       ret_slow_syscall
 197
 198         .align  5
 199 #ifdef CONFIG_ALIGNMENT_TRAP
 200         .type   __cr_alignment, #object
 201 __cr_alignment:
 202         .word   cr_alignment
 203 #endif
 204
 205         .type   sys_call_table, #object
 206 ENTRY(sys_call_table)
 207 #include "calls.S"
 208
 209 /*============================================================================
 210  * Special system call wrappers
 211  */
 212 @ r0 = syscall number
 213 @ r5 = syscall table
 214                 .type   sys_syscall, #function
 215 sys_syscall:
 216                 eor     scno, r0, #__NR_SYSCALL_BASE
 217                 cmp     scno, #__NR_syscall - __NR_SYSCALL_BASE
 218                 cmpne   scno, #NR_syscalls      @ check range
 219                 stmloia sp, {r5, r6}            @ shuffle args
 220                 movlo   r0, r1
 221                 movlo   r1, r2
 222                 movlo   r2, r3
 223                 movlo   r3, r4
 224                 ldrlo   pc, [tbl, scno, lsl #2]
 225                 b       sys_ni_syscall
 226
 227 sys_fork_wrapper:
 228                 add     r0, sp, #S_OFF
 229                 b       sys_fork
 230
 231 sys_vfork_wrapper:
 232                 add     r0, sp, #S_OFF
 233                 b       sys_vfork
 234
 235 sys_execve_wrapper:
 236                 add     r3, sp, #S_OFF
 237                 b       sys_execve
 238
 239 sys_clone_wrapper:
 240                 add     ip, sp, #S_OFF
 241                 str     ip, [sp, #4]
 242                 b       sys_clone
 243
 244 sys_sigsuspend_wrapper:
 245                 add     r3, sp, #S_OFF
 246                 b       sys_sigsuspend
 247
 248 sys_rt_sigsuspend_wrapper:
 249                 add     r2, sp, #S_OFF
 250                 b       sys_rt_sigsuspend
 251
 252 sys_sigreturn_wrapper:
 253                 add     r0, sp, #S_OFF
 254                 b       sys_sigreturn
 255
 256 sys_rt_sigreturn_wrapper:
 257                 add     r0, sp, #S_OFF
 258                 b       sys_rt_sigreturn
 259
 260 sys_sigaltstack_wrapper:
 261                 ldr     r2, [sp, #S_OFF + S_SP]
 262                 b       do_sigaltstack
 263
 264 sys_futex_wrapper:
 265                 str     r5, [sp, #4]            @ push sixth arg
 266                 b       sys_futex
 267
 268 sys_arm_fadvise64_64_wrapper:
 269                 str     r5, [sp, #4]            @ push r5 to stack
 270                 b       sys_arm_fadvise64_64
 271
 272 /*
 273  * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
 274  * offset, we return EINVAL.
 275  */
 276 sys_mmap2:
 277 #if PAGE_SHIFT > 12
 278                 tst     r5, #PGOFF_MASK
 279                 moveq   r5, r5, lsr #PAGE_SHIFT - 12
 280                 streq   r5, [sp, #4]
 281                 beq     do_mmap2
 282                 mov     r0, #-EINVAL
 283                 RETINSTR(mov,pc, lr)
 284 #else
 285                 str     r5, [sp, #4]
 286                 b       do_mmap2
 287 #endif