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
64 ENDPROC(ret_fast_syscall)
67 * "slow" syscall return path. "why" tells us if this was a real syscall.
71 disable_irq @ disable interrupts
72 ENTRY(ret_to_user_from_irq)
73 ldr r1, [tsk, #TI_FLAGS]
74 tst r1, #_TIF_WORK_MASK
79 /* perform architecture specific actions before user return */
80 arch_ret_to_user r1, lr
81 ct_user_enter save = 0
83 restore_user_regs fast = 0, offset = 0
84 ENDPROC(ret_to_user_from_irq)
88 * This is how we return from a fork.
96 1: get_thread_info tsk
98 ENDPROC(ret_from_fork)
101 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
105 * Ensure that the system call table is equal to __NR_syscalls,
106 * which is the value the rest of the system sees
108 .ifne NR_syscalls - __NR_syscalls
109 .error "__NR_syscalls is not equal to the size of the syscall table"
113 #define CALL(x) .long x
115 /*=============================================================================
117 *-----------------------------------------------------------------------------
122 #ifdef CONFIG_CPU_V7M
125 sub sp, sp, #S_FRAME_SIZE
126 stmia sp, {r0 - r12} @ Calling r0 - r12
127 ARM( add r8, sp, #S_PC )
128 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
130 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
131 mrs r8, spsr @ called from non-FIQ mode, so ok.
132 str lr, [sp, #S_PC] @ Save calling PC
133 str r8, [sp, #S_PSR] @ Save CPSR
134 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
137 alignment_trap r10, ip, __cr_alignment
143 * Get the system call number.
146 #if defined(CONFIG_OABI_COMPAT)
149 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
150 * value to determine if it is an EABI or an old ABI call.
152 #ifdef CONFIG_ARM_THUMB
154 movne r10, #0 @ no thumb OABI emulation
155 USER( ldreq r10, [lr, #-4] ) @ get SWI instruction
157 USER( ldr r10, [lr, #-4] ) @ get SWI instruction
159 ARM_BE8(rev r10, r10) @ little endian instruction
161 #elif defined(CONFIG_AEABI)
164 * Pure EABI user space always put syscall number into scno (r7).
166 #elif defined(CONFIG_ARM_THUMB)
167 /* Legacy ABI only, possibly thumb mode. */
168 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
169 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
170 USER( ldreq scno, [lr, #-4] )
173 /* Legacy ABI only. */
174 USER( ldr scno, [lr, #-4] ) @ get SWI instruction
179 adr tbl, sys_call_table @ load syscall table pointer
181 #if defined(CONFIG_OABI_COMPAT)
183 * If the swi argument is zero, this is an EABI call and we do nothing.
185 * If this is an old ABI call, get the syscall number into scno and
186 * get the old ABI syscall table address.
188 bics r10, r10, #0xff000000
189 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
190 ldrne tbl, =sys_oabi_call_table
191 #elif !defined(CONFIG_AEABI)
192 bic scno, scno, #0xff000000 @ mask off SWI op-code
193 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
197 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
198 stmdb sp!, {r4, r5} @ push fifth and sixth args
200 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
203 cmp scno, #NR_syscalls @ check upper syscall limit
204 badr lr, ret_fast_syscall @ return address
205 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
208 2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
209 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
211 mov why, #0 @ no longer a real syscall
212 b sys_ni_syscall @ not private func
214 #if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
216 * We failed to handle a fault trying to access the page
217 * containing the swi instruction, but we're not really in a
218 * position to return -EFAULT. Instead, return back to the
219 * instruction and re-enter the user fault handling path trying
220 * to page it in. This will likely result in sending SEGV to the
231 * This is the really slow path. We're going to be doing
232 * context switches, and waiting for our parent to respond.
237 bl syscall_trace_enter
239 badr lr, __sys_trace_return @ return address
240 mov scno, r0 @ syscall number (possibly new)
241 add r1, sp, #S_R0 + S_OFF @ pointer to regs
242 cmp scno, #NR_syscalls @ check upper syscall limit
243 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
244 stmccia sp, {r4, r5} @ and update the stack args
245 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
246 cmp scno, #-1 @ skip the syscall?
248 add sp, sp, #S_OFF @ restore stack
252 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
254 bl syscall_trace_exit
258 #ifdef CONFIG_ALIGNMENT_TRAP
259 .type __cr_alignment, #object
266 * This is the syscall table declaration for native ABI syscalls.
267 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
269 #define ABI(native, compat) native
271 #define OBSOLETE(syscall) sys_ni_syscall
273 #define OBSOLETE(syscall) syscall
276 .type sys_call_table, #object
277 ENTRY(sys_call_table)
282 /*============================================================================
283 * Special system call wrappers
285 @ r0 = syscall number
288 bic scno, r0, #__NR_OABI_SYSCALL_BASE
289 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
290 cmpne scno, #NR_syscalls @ check range
291 stmloia sp, {r5, r6} @ shuffle args
296 ldrlo pc, [tbl, scno, lsl #2]
300 sys_sigreturn_wrapper:
302 mov why, #0 @ prevent syscall restart handling
304 ENDPROC(sys_sigreturn_wrapper)
306 sys_rt_sigreturn_wrapper:
308 mov why, #0 @ prevent syscall restart handling
310 ENDPROC(sys_rt_sigreturn_wrapper)
312 sys_statfs64_wrapper:
316 ENDPROC(sys_statfs64_wrapper)
318 sys_fstatfs64_wrapper:
322 ENDPROC(sys_fstatfs64_wrapper)
325 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
326 * offset, we return EINVAL.
331 moveq r5, r5, lsr #PAGE_SHIFT - 12
342 #ifdef CONFIG_OABI_COMPAT
345 * These are syscalls with argument register differences
351 ENDPROC(sys_oabi_pread64)
356 ENDPROC(sys_oabi_pwrite64)
362 ENDPROC(sys_oabi_truncate64)
364 sys_oabi_ftruncate64:
368 ENDPROC(sys_oabi_ftruncate64)
375 ENDPROC(sys_oabi_readahead)
378 * Let's declare a second syscall table for old ABI binaries
379 * using the compatibility syscall entries.
381 #define ABI(native, compat) compat
382 #define OBSOLETE(syscall) syscall
384 .type sys_oabi_call_table, #object
385 ENTRY(sys_oabi_call_table)