2 * linux/arch/arm/kernel/entry-common.S
4 * Copyright (C) 2000 Russell King
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.
11 #include <asm/assembler.h>
12 #include <asm/unistd.h>
13 #include <asm/ftrace.h>
14 #include <asm/unwind.h>
16 #ifdef CONFIG_NEED_RET_TO_USER
17 #include <mach/entry-macro.S>
19 .macro arch_ret_to_user, tmp1, tmp2
23 #include "entry-header.S"
28 * This is the fast syscall return path. We do as little as
29 * possible here, and this includes saving r0 back into the SVC
35 disable_irq @ disable interrupts
36 ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
37 tst r1, #_TIF_SYSCALL_WORK
38 bne __sys_trace_return
39 tst r1, #_TIF_WORK_MASK
43 /* perform architecture specific actions before user return */
44 arch_ret_to_user r1, lr
47 restore_user_regs fast = 1, offset = S_OFF
51 * Ok, we need to do extra processing, enter the slow path.
54 str r0, [sp, #S_R0+S_OFF]! @ returned r0
57 mov r2, why @ 'syscall'
61 movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
62 ldmia sp, {r0 - r6} @ have to reload r0 - r6
63 b local_restart @ ... and off we go
66 * "slow" syscall return path. "why" tells us if this was a real syscall.
70 disable_irq @ disable interrupts
71 ENTRY(ret_to_user_from_irq)
72 ldr r1, [tsk, #TI_FLAGS]
73 tst r1, #_TIF_WORK_MASK
78 /* perform architecture specific actions before user return */
79 arch_ret_to_user r1, lr
80 ct_user_enter save = 0
82 restore_user_regs fast = 0, offset = 0
83 ENDPROC(ret_to_user_from_irq)
87 * This is how we return from a fork.
95 1: get_thread_info tsk
97 ENDPROC(ret_from_fork)
100 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
104 * Ensure that the system call table is equal to __NR_syscalls,
105 * which is the value the rest of the system sees
107 .ifne NR_syscalls - __NR_syscalls
108 .error "__NR_syscalls is not equal to the size of the syscall table"
112 #define CALL(x) .long x
114 /*=============================================================================
116 *-----------------------------------------------------------------------------
121 #ifdef CONFIG_CPU_V7M
124 sub sp, sp, #S_FRAME_SIZE
125 stmia sp, {r0 - r12} @ Calling r0 - r12
126 ARM( add r8, sp, #S_PC )
127 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
129 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
130 mrs r8, spsr @ called from non-FIQ mode, so ok.
131 str lr, [sp, #S_PC] @ Save calling PC
132 str r8, [sp, #S_PSR] @ Save CPSR
133 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
136 alignment_trap r10, ip, __cr_alignment
142 * Get the system call number.
145 #if defined(CONFIG_OABI_COMPAT)
148 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
149 * value to determine if it is an EABI or an old ABI call.
151 #ifdef CONFIG_ARM_THUMB
153 movne r10, #0 @ no thumb OABI emulation
154 USER( ldreq r10, [lr, #-4] ) @ get SWI instruction
156 USER( ldr r10, [lr, #-4] ) @ get SWI instruction
158 ARM_BE8(rev r10, r10) @ little endian instruction
160 #elif defined(CONFIG_AEABI)
163 * Pure EABI user space always put syscall number into scno (r7).
165 #elif defined(CONFIG_ARM_THUMB)
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 USER( ldreq scno, [lr, #-4] )
172 /* Legacy ABI only. */
173 USER( ldr scno, [lr, #-4] ) @ get SWI instruction
176 adr tbl, sys_call_table @ load syscall table pointer
178 #if defined(CONFIG_OABI_COMPAT)
180 * If the swi argument is zero, this is an EABI call and we do nothing.
182 * If this is an old ABI call, get the syscall number into scno and
183 * get the old ABI syscall table address.
185 bics r10, r10, #0xff000000
186 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
187 ldrne tbl, =sys_oabi_call_table
188 #elif !defined(CONFIG_AEABI)
189 bic scno, scno, #0xff000000 @ mask off SWI op-code
190 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
194 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
195 stmdb sp!, {r4, r5} @ push fifth and sixth args
197 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
200 cmp scno, #NR_syscalls @ check upper syscall limit
201 badr lr, ret_fast_syscall @ return address
202 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
205 2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
206 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
208 mov why, #0 @ no longer a real syscall
209 b sys_ni_syscall @ not private func
211 #if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
213 * We failed to handle a fault trying to access the page
214 * containing the swi instruction, but we're not really in a
215 * position to return -EFAULT. Instead, return back to the
216 * instruction and re-enter the user fault handling path trying
217 * to page it in. This will likely result in sending SEGV to the
228 * This is the really slow path. We're going to be doing
229 * context switches, and waiting for our parent to respond.
234 bl syscall_trace_enter
236 badr lr, __sys_trace_return @ return address
237 mov scno, r0 @ syscall number (possibly new)
238 add r1, sp, #S_R0 + S_OFF @ pointer to regs
239 cmp scno, #NR_syscalls @ check upper syscall limit
240 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
241 stmccia sp, {r4, r5} @ and update the stack args
242 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
243 cmp scno, #-1 @ skip the syscall?
245 add sp, sp, #S_OFF @ restore stack
249 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
251 bl syscall_trace_exit
255 #ifdef CONFIG_ALIGNMENT_TRAP
256 .type __cr_alignment, #object
263 * This is the syscall table declaration for native ABI syscalls.
264 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
266 #define ABI(native, compat) native
268 #define OBSOLETE(syscall) sys_ni_syscall
270 #define OBSOLETE(syscall) syscall
273 .type sys_call_table, #object
274 ENTRY(sys_call_table)
279 /*============================================================================
280 * Special system call wrappers
282 @ r0 = syscall number
285 bic scno, r0, #__NR_OABI_SYSCALL_BASE
286 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
287 cmpne scno, #NR_syscalls @ check range
288 stmloia sp, {r5, r6} @ shuffle args
293 ldrlo pc, [tbl, scno, lsl #2]
297 sys_sigreturn_wrapper:
299 mov why, #0 @ prevent syscall restart handling
301 ENDPROC(sys_sigreturn_wrapper)
303 sys_rt_sigreturn_wrapper:
305 mov why, #0 @ prevent syscall restart handling
307 ENDPROC(sys_rt_sigreturn_wrapper)
309 sys_statfs64_wrapper:
313 ENDPROC(sys_statfs64_wrapper)
315 sys_fstatfs64_wrapper:
319 ENDPROC(sys_fstatfs64_wrapper)
322 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
323 * offset, we return EINVAL.
328 moveq r5, r5, lsr #PAGE_SHIFT - 12
339 #ifdef CONFIG_OABI_COMPAT
342 * These are syscalls with argument register differences
348 ENDPROC(sys_oabi_pread64)
353 ENDPROC(sys_oabi_pwrite64)
359 ENDPROC(sys_oabi_truncate64)
361 sys_oabi_ftruncate64:
365 ENDPROC(sys_oabi_ftruncate64)
372 ENDPROC(sys_oabi_readahead)
375 * Let's declare a second syscall table for old ABI binaries
376 * using the compatibility syscall entries.
378 #define ABI(native, compat) compat
379 #define OBSOLETE(syscall) syscall
381 .type sys_oabi_call_table, #object
382 ENTRY(sys_oabi_call_table)