[ARM] 3112/1: old ABI compat: config option to turn it on
[deliverable/linux.git] / arch / arm / kernel / entry-common.S
CommitLineData
1da177e4
LT
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
1da177e4
LT
12#include <asm/unistd.h>
13
14#include "entry-header.S"
15
1da177e4
LT
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 */
23ret_fast_syscall:
1ec42c0c 24 disable_irq @ disable interrupts
1da177e4
LT
25 ldr r1, [tsk, #TI_FLAGS]
26 tst r1, #_TIF_WORK_MASK
27 bne fast_work_pending
f4dc9a4c
RK
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
1da177e4
LT
37
38/*
39 * Ok, we need to do extra processing, enter the slow path.
40 */
41fast_work_pending:
42 str r0, [sp, #S_R0+S_OFF]! @ returned r0
43work_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
a6c61e9d 51 b ret_slow_syscall @ Check work again
1da177e4
LT
52
53work_resched:
54 bl schedule
55/*
56 * "slow" syscall return path. "why" tells us if this was a real syscall.
57 */
58ENTRY(ret_to_user)
59ret_slow_syscall:
1ec42c0c 60 disable_irq @ disable interrupts
1da177e4
LT
61 ldr r1, [tsk, #TI_FLAGS]
62 tst r1, #_TIF_WORK_MASK
63 bne work_pending
64no_work_pending:
f4dc9a4c
RK
65 @ slow_restore_user_regs
66 ldr r1, [sp, #S_PSR] @ get calling cpsr
67 ldr lr, [sp, #S_PC]! @ get pc
68 msr spsr_cxsf, r1 @ save in spsr_svc
69 ldmdb sp, {r0 - lr}^ @ get calling r1 - lr
70 mov r0, r0
71 add sp, sp, #S_FRAME_SIZE - S_PC
72 movs pc, lr @ return & move spsr_svc into cpsr
1da177e4
LT
73
74/*
75 * This is how we return from a fork.
76 */
77ENTRY(ret_from_fork)
78 bl schedule_tail
79 get_thread_info tsk
80 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
81 mov why, #1
82 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
83 beq ret_slow_syscall
84 mov r1, sp
85 mov r0, #1 @ trace exit [IP = 1]
86 bl syscall_trace
87 b ret_slow_syscall
88
89
90#include "calls.S"
91
92/*=============================================================================
93 * SWI handler
94 *-----------------------------------------------------------------------------
95 */
96
97 /* If we're optimising for StrongARM the resulting code won't
98 run on an ARM7 and we can save a couple of instructions.
99 --pb */
100#ifdef CONFIG_CPU_ARM710
3f2829a3
NP
101#define A710(code...) code
102.Larm710bug:
1da177e4
LT
103 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr
104 mov r0, r0
1da177e4 105 add sp, sp, #S_FRAME_SIZE
60ac133a 106 subs pc, lr, #4
1da177e4 107#else
3f2829a3 108#define A710(code...)
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109#endif
110
111 .align 5
112ENTRY(vector_swi)
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RK
113 sub sp, sp, #S_FRAME_SIZE
114 stmia sp, {r0 - r12} @ Calling r0 - r12
115 add r8, sp, #S_PC
116 stmdb r8, {sp, lr}^ @ Calling sp, lr
117 mrs r8, spsr @ called from non-FIQ mode, so ok.
118 str lr, [sp, #S_PC] @ Save calling PC
119 str r8, [sp, #S_PSR] @ Save CPSR
120 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
1da177e4 121 zero_fp
e0f9f4a6
RK
122
123 /*
124 * Get the system call number.
125 */
3f2829a3 126
dd35afc2 127#if defined(CONFIG_OABI_COMPAT)
3f2829a3 128
dd35afc2
NP
129 /*
130 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
131 * value to determine if it is an EABI or an old ABI call.
132 */
133#ifdef CONFIG_ARM_THUMB
134 tst r8, #PSR_T_BIT
135 movne r10, #0 @ no thumb OABI emulation
136 ldreq r10, [lr, #-4] @ get SWI instruction
137#else
138 ldr r10, [lr, #-4] @ get SWI instruction
139 A710( and ip, r10, #0x0f000000 @ check for SWI )
140 A710( teq ip, #0x0f000000 )
141 A710( bne .Larm710bug )
142#endif
143
144#elif defined(CONFIG_AEABI)
145
146 /*
147 * Pure EABI user space always put syscall number into scno (r7).
148 */
3f2829a3
NP
149 A710( ldr ip, [lr, #-4] @ get SWI instruction )
150 A710( and ip, ip, #0x0f000000 @ check for SWI )
151 A710( teq ip, #0x0f000000 )
152 A710( bne .Larm710bug )
dd35afc2 153
3f2829a3 154#elif defined(CONFIG_ARM_THUMB)
dd35afc2
NP
155
156 /* Legacy ABI only, possibly thumb mode. */
e0f9f4a6
RK
157 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
158 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
159 ldreq scno, [lr, #-4]
dd35afc2 160
e0f9f4a6 161#else
dd35afc2
NP
162
163 /* Legacy ABI only. */
e0f9f4a6 164 ldr scno, [lr, #-4] @ get SWI instruction
3f2829a3
NP
165 A710( and ip, scno, #0x0f000000 @ check for SWI )
166 A710( teq ip, #0x0f000000 )
167 A710( bne .Larm710bug )
dd35afc2 168
e0f9f4a6 169#endif
1da177e4
LT
170
171#ifdef CONFIG_ALIGNMENT_TRAP
172 ldr ip, __cr_alignment
173 ldr ip, [ip]
174 mcr p15, 0, ip, c1, c0 @ update control register
175#endif
1ec42c0c 176 enable_irq
1da177e4 177
1da177e4 178 get_thread_info tsk
dd35afc2 179 adr tbl, sys_call_table @ load syscall table pointer
1da177e4 180 ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing
dd35afc2
NP
181
182#if defined(CONFIG_OABI_COMPAT)
183 /*
184 * If the swi argument is zero, this is an EABI call and we do nothing.
185 *
186 * If this is an old ABI call, get the syscall number into scno and
187 * get the old ABI syscall table address.
188 */
189 bics r10, r10, #0xff000000
190 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
191 ldrne tbl, =sys_oabi_call_table
192#elif !defined(CONFIG_AEABI)
1da177e4 193 bic scno, scno, #0xff000000 @ mask off SWI op-code
e0f9f4a6 194 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
3f2829a3 195#endif
dd35afc2 196
3f2829a3 197 stmdb sp!, {r4, r5} @ push fifth and sixth args
1da177e4
LT
198 tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
199 bne __sys_trace
200
1da177e4 201 cmp scno, #NR_syscalls @ check upper syscall limit
3f2829a3 202 adr lr, ret_fast_syscall @ return address
1da177e4
LT
203 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
204
205 add r1, sp, #S_OFF
2062: mov why, #0 @ no longer a real syscall
e0f9f4a6
RK
207 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
208 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
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LT
209 bcs arm_syscall
210 b sys_ni_syscall @ not private func
211
212 /*
213 * This is the really slow path. We're going to be doing
214 * context switches, and waiting for our parent to respond.
215 */
216__sys_trace:
217 add r1, sp, #S_OFF
218 mov r0, #0 @ trace entry [IP = 0]
219 bl syscall_trace
220
221 adr lr, __sys_trace_return @ return address
222 add r1, sp, #S_R0 + S_OFF @ pointer to regs
223 cmp scno, #NR_syscalls @ check upper syscall limit
224 ldmccia r1, {r0 - r3} @ have to reload r0 - r3
225 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
226 b 2b
227
228__sys_trace_return:
229 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
230 mov r1, sp
231 mov r0, #1 @ trace exit [IP = 1]
232 bl syscall_trace
233 b ret_slow_syscall
234
235 .align 5
236#ifdef CONFIG_ALIGNMENT_TRAP
237 .type __cr_alignment, #object
238__cr_alignment:
239 .word cr_alignment
dd35afc2
NP
240#endif
241 .ltorg
242
243/*
244 * This is the syscall table declaration for native ABI syscalls.
245 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
246 */
247#define ABI(native, compat) native
248#ifdef CONFIG_AEABI
249#define OBSOLETE(syscall) sys_ni_syscall
250#else
251#define OBSOLETE(syscall) syscall
1da177e4
LT
252#endif
253
254 .type sys_call_table, #object
255ENTRY(sys_call_table)
256#include "calls.S"
dd35afc2
NP
257#undef ABI
258#undef OBSOLETE
1da177e4
LT
259
260/*============================================================================
261 * Special system call wrappers
262 */
263@ r0 = syscall number
567bd980 264@ r8 = syscall table
1da177e4
LT
265 .type sys_syscall, #function
266sys_syscall:
dd35afc2 267 eor scno, r0, #__NR_OABI_SYSCALL_BASE
1da177e4
LT
268 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
269 cmpne scno, #NR_syscalls @ check range
270 stmloia sp, {r5, r6} @ shuffle args
271 movlo r0, r1
272 movlo r1, r2
273 movlo r2, r3
274 movlo r3, r4
275 ldrlo pc, [tbl, scno, lsl #2]
276 b sys_ni_syscall
277
278sys_fork_wrapper:
279 add r0, sp, #S_OFF
280 b sys_fork
281
282sys_vfork_wrapper:
283 add r0, sp, #S_OFF
284 b sys_vfork
285
286sys_execve_wrapper:
287 add r3, sp, #S_OFF
288 b sys_execve
289
290sys_clone_wrapper:
291 add ip, sp, #S_OFF
292 str ip, [sp, #4]
293 b sys_clone
294
295sys_sigsuspend_wrapper:
296 add r3, sp, #S_OFF
297 b sys_sigsuspend
298
299sys_rt_sigsuspend_wrapper:
300 add r2, sp, #S_OFF
301 b sys_rt_sigsuspend
302
303sys_sigreturn_wrapper:
304 add r0, sp, #S_OFF
305 b sys_sigreturn
306
307sys_rt_sigreturn_wrapper:
308 add r0, sp, #S_OFF
309 b sys_rt_sigreturn
310
311sys_sigaltstack_wrapper:
312 ldr r2, [sp, #S_OFF + S_SP]
313 b do_sigaltstack
314
713c4815
NP
315sys_statfs64_wrapper:
316 teq r1, #88
317 moveq r1, #84
318 b sys_statfs64
319
320sys_fstatfs64_wrapper:
321 teq r1, #88
322 moveq r1, #84
323 b sys_fstatfs64
324
1da177e4
LT
325/*
326 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
327 * offset, we return EINVAL.
328 */
329sys_mmap2:
330#if PAGE_SHIFT > 12
331 tst r5, #PGOFF_MASK
332 moveq r5, r5, lsr #PAGE_SHIFT - 12
333 streq r5, [sp, #4]
334 beq do_mmap2
335 mov r0, #-EINVAL
336 RETINSTR(mov,pc, lr)
337#else
338 str r5, [sp, #4]
339 b do_mmap2
340#endif
687ad019
NP
341
342#ifdef CONFIG_OABI_COMPAT
dd35afc2 343
687ad019
NP
344/*
345 * These are syscalls with argument register differences
346 */
347
348sys_oabi_pread64:
349 stmia sp, {r3, r4}
350 b sys_pread64
351
352sys_oabi_pwrite64:
353 stmia sp, {r3, r4}
354 b sys_pwrite64
355
356sys_oabi_truncate64:
357 mov r3, r2
358 mov r2, r1
359 b sys_truncate64
360
361sys_oabi_ftruncate64:
362 mov r3, r2
363 mov r2, r1
364 b sys_ftruncate64
365
366sys_oabi_readahead:
367 str r3, [sp]
368 mov r3, r2
369 mov r2, r1
370 b sys_readahead
371
dd35afc2
NP
372/*
373 * Let's declare a second syscall table for old ABI binaries
374 * using the compatibility syscall entries.
375 */
376#define ABI(native, compat) compat
377#define OBSOLETE(syscall) syscall
378
379 .type sys_oabi_call_table, #object
380ENTRY(sys_oabi_call_table)
381#include "calls.S"
382#undef ABI
383#undef OBSOLETE
384
687ad019
NP
385#endif
386
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