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]
37 tst r1, #_TIF_WORK_MASK
41 /* perform architecture specific actions before user return */
42 arch_ret_to_user r1, lr
45 restore_user_regs fast = 1, offset = S_OFF
49 * Ok, we need to do extra processing, enter the slow path.
52 str r0, [sp, #S_R0+S_OFF]! @ returned r0
55 mov r2, why @ 'syscall'
59 movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
60 ldmia sp, {r0 - r6} @ have to reload r0 - r6
61 b local_restart @ ... and off we go
64 * "slow" syscall return path. "why" tells us if this was a real syscall.
68 disable_irq @ disable interrupts
69 ENTRY(ret_to_user_from_irq)
70 ldr r1, [tsk, #TI_FLAGS]
71 tst r1, #_TIF_WORK_MASK
76 /* perform architecture specific actions before user return */
77 arch_ret_to_user r1, lr
78 ct_user_enter save = 0
80 restore_user_regs fast = 0, offset = 0
81 ENDPROC(ret_to_user_from_irq)
85 * This is how we return from a fork.
93 1: get_thread_info tsk
95 ENDPROC(ret_from_fork)
98 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
102 * Ensure that the system call table is equal to __NR_syscalls,
103 * which is the value the rest of the system sees
105 .ifne NR_syscalls - __NR_syscalls
106 .error "__NR_syscalls is not equal to the size of the syscall table"
110 #define CALL(x) .long x
112 /*=============================================================================
114 *-----------------------------------------------------------------------------
119 #ifdef CONFIG_CPU_V7M
122 sub sp, sp, #S_FRAME_SIZE
123 stmia sp, {r0 - r12} @ Calling r0 - r12
124 ARM( add r8, sp, #S_PC )
125 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
127 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
128 mrs r8, spsr @ called from non-FIQ mode, so ok.
129 str lr, [sp, #S_PC] @ Save calling PC
130 str r8, [sp, #S_PSR] @ Save CPSR
131 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
134 alignment_trap r10, ip, __cr_alignment
140 * Get the system call number.
143 #if defined(CONFIG_OABI_COMPAT)
146 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
147 * value to determine if it is an EABI or an old ABI call.
149 #ifdef CONFIG_ARM_THUMB
151 movne r10, #0 @ no thumb OABI emulation
152 USER( ldreq r10, [lr, #-4] ) @ get SWI instruction
154 USER( ldr r10, [lr, #-4] ) @ get SWI instruction
156 ARM_BE8(rev r10, r10) @ little endian instruction
158 #elif defined(CONFIG_AEABI)
161 * Pure EABI user space always put syscall number into scno (r7).
163 #elif defined(CONFIG_ARM_THUMB)
164 /* Legacy ABI only, possibly thumb mode. */
165 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
166 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
167 USER( ldreq scno, [lr, #-4] )
170 /* Legacy ABI only. */
171 USER( ldr scno, [lr, #-4] ) @ get SWI instruction
174 adr tbl, sys_call_table @ load syscall table pointer
176 #if defined(CONFIG_OABI_COMPAT)
178 * If the swi argument is zero, this is an EABI call and we do nothing.
180 * If this is an old ABI call, get the syscall number into scno and
181 * get the old ABI syscall table address.
183 bics r10, r10, #0xff000000
184 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
185 ldrne tbl, =sys_oabi_call_table
186 #elif !defined(CONFIG_AEABI)
187 bic scno, scno, #0xff000000 @ mask off SWI op-code
188 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
192 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
193 stmdb sp!, {r4, r5} @ push fifth and sixth args
195 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
198 cmp scno, #NR_syscalls @ check upper syscall limit
199 adr lr, BSYM(ret_fast_syscall) @ return address
200 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
203 2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
204 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
206 mov why, #0 @ no longer a real syscall
207 b sys_ni_syscall @ not private func
209 #if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
211 * We failed to handle a fault trying to access the page
212 * containing the swi instruction, but we're not really in a
213 * position to return -EFAULT. Instead, return back to the
214 * instruction and re-enter the user fault handling path trying
215 * to page it in. This will likely result in sending SEGV to the
226 * This is the really slow path. We're going to be doing
227 * context switches, and waiting for our parent to respond.
232 bl syscall_trace_enter
234 adr lr, BSYM(__sys_trace_return) @ return address
235 mov scno, r0 @ syscall number (possibly new)
236 add r1, sp, #S_R0 + S_OFF @ pointer to regs
237 cmp scno, #NR_syscalls @ check upper syscall limit
238 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
239 stmccia sp, {r4, r5} @ and update the stack args
240 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
241 cmp scno, #-1 @ skip the syscall?
243 add sp, sp, #S_OFF @ restore stack
247 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
249 bl syscall_trace_exit
253 #ifdef CONFIG_ALIGNMENT_TRAP
254 .type __cr_alignment, #object
261 * This is the syscall table declaration for native ABI syscalls.
262 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
264 #define ABI(native, compat) native
266 #define OBSOLETE(syscall) sys_ni_syscall
268 #define OBSOLETE(syscall) syscall
271 .type sys_call_table, #object
272 ENTRY(sys_call_table)
277 /*============================================================================
278 * Special system call wrappers
280 @ r0 = syscall number
283 bic scno, r0, #__NR_OABI_SYSCALL_BASE
284 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
285 cmpne scno, #NR_syscalls @ check range
286 stmloia sp, {r5, r6} @ shuffle args
291 ldrlo pc, [tbl, scno, lsl #2]
295 sys_sigreturn_wrapper:
297 mov why, #0 @ prevent syscall restart handling
299 ENDPROC(sys_sigreturn_wrapper)
301 sys_rt_sigreturn_wrapper:
303 mov why, #0 @ prevent syscall restart handling
305 ENDPROC(sys_rt_sigreturn_wrapper)
307 sys_statfs64_wrapper:
311 ENDPROC(sys_statfs64_wrapper)
313 sys_fstatfs64_wrapper:
317 ENDPROC(sys_fstatfs64_wrapper)
320 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
321 * offset, we return EINVAL.
326 moveq r5, r5, lsr #PAGE_SHIFT - 12
337 #ifdef CONFIG_OABI_COMPAT
340 * These are syscalls with argument register differences
346 ENDPROC(sys_oabi_pread64)
351 ENDPROC(sys_oabi_pwrite64)
357 ENDPROC(sys_oabi_truncate64)
359 sys_oabi_ftruncate64:
363 ENDPROC(sys_oabi_ftruncate64)
370 ENDPROC(sys_oabi_readahead)
373 * Let's declare a second syscall table for old ABI binaries
374 * using the compatibility syscall entries.
376 #define ABI(native, compat) compat
377 #define OBSOLETE(syscall) syscall
379 .type sys_oabi_call_table, #object
380 ENTRY(sys_oabi_call_table)