| blob | a6c301e90a3b3fd6cc43508b73d3710244395164 |
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 */
11 #include <asm/unistd.h>
12 #include <asm/ftrace.h>
13 #include <asm/unwind.h>
15 #ifdef CONFIG_NEED_RET_TO_USER
16 #include <mach/entry-macro.S>
17 #else
18 .macro arch_ret_to_user, tmp1, tmp2
19 .endm
20 #endif
22 #include "entry-header.S"
25 .align 5
26 /*
27 * This is the fast syscall return path. We do as little as
28 * possible here, and this includes saving r0 back into the SVC
29 * stack.
30 */
31 ret_fast_syscall:
32 UNWIND(.fnstart )
33 UNWIND(.cantunwind )
34 disable_irq @ disable interrupts
35 ldr r1, [tsk, #TI_FLAGS]
36 tst r1, #_TIF_WORK_MASK
37 bne fast_work_pending
38 #if defined(CONFIG_IRQSOFF_TRACER)
39 asm_trace_hardirqs_on
40 #endif
42 /* perform architecture specific actions before user return */
43 arch_ret_to_user r1, lr
45 restore_user_regs fast = 1, offset = S_OFF
46 UNWIND(.fnend )
48 /*
49 * Ok, we need to do extra processing, enter the slow path.
50 */
51 fast_work_pending:
52 str r0, [sp, #S_R0+S_OFF]! @ returned r0
53 work_pending:
54 mov r0, sp @ 'regs'
55 mov r2, why @ 'syscall'
56 bl do_work_pending
57 cmp r0, #0
58 beq no_work_pending
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
63 /*
64 * "slow" syscall return path. "why" tells us if this was a real syscall.
65 */
66 ENTRY(ret_to_user)
67 ret_slow_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
72 bne work_pending
73 no_work_pending:
74 #if defined(CONFIG_IRQSOFF_TRACER)
75 asm_trace_hardirqs_on
76 #endif
77 /* perform architecture specific actions before user return */
78 arch_ret_to_user r1, lr
80 restore_user_regs fast = 0, offset = 0
81 ENDPROC(ret_to_user_from_irq)
82 ENDPROC(ret_to_user)
84 /*
85 * This is how we return from a fork.
86 */
87 ENTRY(ret_from_fork)
88 bl schedule_tail
89 cmp r5, #0
90 movne r0, r4
91 adrne lr, BSYM(1f)
92 movne pc, r5
93 1: get_thread_info tsk
94 b ret_slow_syscall
95 ENDPROC(ret_from_fork)
97 .equ NR_syscalls,0
98 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
99 #include "calls.S"
101 /*
102 * Ensure that the system call table is equal to __NR_syscalls,
103 * which is the value the rest of the system sees
104 */
105 .ifne NR_syscalls - __NR_syscalls
106 .error "__NR_syscalls is not equal to the size of the syscall table"
107 .endif
109 #undef CALL
110 #define CALL(x) .long x
112 #ifdef CONFIG_FUNCTION_TRACER
113 /*
114 * When compiling with -pg, gcc inserts a call to the mcount routine at the
115 * start of every function. In mcount, apart from the function's address (in
116 * lr), we need to get hold of the function's caller's address.
117 *
118 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
119 *
120 * bl mcount
121 *
122 * These versions have the limitation that in order for the mcount routine to
123 * be able to determine the function's caller's address, an APCS-style frame
124 * pointer (which is set up with something like the code below) is required.
125 *
126 * mov ip, sp
127 * push {fp, ip, lr, pc}
128 * sub fp, ip, #4
129 *
130 * With EABI, these frame pointers are not available unless -mapcs-frame is
131 * specified, and if building as Thumb-2, not even then.
132 *
133 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
134 * with call sites like:
135 *
136 * push {lr}
137 * bl __gnu_mcount_nc
138 *
139 * With these compilers, frame pointers are not necessary.
140 *
141 * mcount can be thought of as a function called in the middle of a subroutine
142 * call. As such, it needs to be transparent for both the caller and the
143 * callee: the original lr needs to be restored when leaving mcount, and no
144 * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
145 * clobber the ip register. This is OK because the ARM calling convention
146 * allows it to be clobbered in subroutines and doesn't use it to hold
147 * parameters.)
148 *
149 * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
150 * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
151 * arch/arm/kernel/ftrace.c).
152 */
154 #ifndef CONFIG_OLD_MCOUNT
155 #if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
156 #error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
157 #endif
158 #endif
160 .macro mcount_adjust_addr rd, rn
161 bic \rd, \rn, #1 @ clear the Thumb bit if present
162 sub \rd, \rd, #MCOUNT_INSN_SIZE
163 .endm
165 .macro __mcount suffix
166 mcount_enter
167 ldr r0, =ftrace_trace_function
168 ldr r2, [r0]
169 adr r0, .Lftrace_stub
170 cmp r0, r2
171 bne 1f
173 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
174 ldr r1, =ftrace_graph_return
175 ldr r2, [r1]
176 cmp r0, r2
177 bne ftrace_graph_caller\suffix
179 ldr r1, =ftrace_graph_entry
180 ldr r2, [r1]
181 ldr r0, =ftrace_graph_entry_stub
182 cmp r0, r2
183 bne ftrace_graph_caller\suffix
184 #endif
186 mcount_exit
188 1: mcount_get_lr r1 @ lr of instrumented func
189 mcount_adjust_addr r0, lr @ instrumented function
190 adr lr, BSYM(2f)
191 mov pc, r2
192 2: mcount_exit
193 .endm
195 .macro __ftrace_caller suffix
196 mcount_enter
198 mcount_get_lr r1 @ lr of instrumented func
199 mcount_adjust_addr r0, lr @ instrumented function
201 .globl ftrace_call\suffix
202 ftrace_call\suffix:
203 bl ftrace_stub
205 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
206 .globl ftrace_graph_call\suffix
207 ftrace_graph_call\suffix:
208 mov r0, r0
209 #endif
211 mcount_exit
212 .endm
214 .macro __ftrace_graph_caller
215 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
216 #ifdef CONFIG_DYNAMIC_FTRACE
217 @ called from __ftrace_caller, saved in mcount_enter
218 ldr r1, [sp, #16] @ instrumented routine (func)
219 mcount_adjust_addr r1, r1
220 #else
221 @ called from __mcount, untouched in lr
222 mcount_adjust_addr r1, lr @ instrumented routine (func)
223 #endif
224 mov r2, fp @ frame pointer
225 bl prepare_ftrace_return
226 mcount_exit
227 .endm
229 #ifdef CONFIG_OLD_MCOUNT
230 /*
231 * mcount
232 */
234 .macro mcount_enter
235 stmdb sp!, {r0-r3, lr}
236 .endm
238 .macro mcount_get_lr reg
239 ldr \reg, [fp, #-4]
240 .endm
242 .macro mcount_exit
243 ldr lr, [fp, #-4]
244 ldmia sp!, {r0-r3, pc}
245 .endm
247 ENTRY(mcount)
248 #ifdef CONFIG_DYNAMIC_FTRACE
249 stmdb sp!, {lr}
250 ldr lr, [fp, #-4]
251 ldmia sp!, {pc}
252 #else
253 __mcount _old
254 #endif
255 ENDPROC(mcount)
257 #ifdef CONFIG_DYNAMIC_FTRACE
258 ENTRY(ftrace_caller_old)
259 __ftrace_caller _old
260 ENDPROC(ftrace_caller_old)
261 #endif
263 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
264 ENTRY(ftrace_graph_caller_old)
265 __ftrace_graph_caller
266 ENDPROC(ftrace_graph_caller_old)
267 #endif
269 .purgem mcount_enter
270 .purgem mcount_get_lr
271 .purgem mcount_exit
272 #endif
274 /*
275 * __gnu_mcount_nc
276 */
278 .macro mcount_enter
279 stmdb sp!, {r0-r3, lr}
280 .endm
282 .macro mcount_get_lr reg
283 ldr \reg, [sp, #20]
284 .endm
286 .macro mcount_exit
287 ldmia sp!, {r0-r3, ip, lr}
288 mov pc, ip
289 .endm
291 ENTRY(__gnu_mcount_nc)
292 #ifdef CONFIG_DYNAMIC_FTRACE
293 mov ip, lr
294 ldmia sp!, {lr}
295 mov pc, ip
296 #else
297 __mcount
298 #endif
299 ENDPROC(__gnu_mcount_nc)
301 #ifdef CONFIG_DYNAMIC_FTRACE
302 ENTRY(ftrace_caller)
303 __ftrace_caller
304 ENDPROC(ftrace_caller)
305 #endif
307 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
308 ENTRY(ftrace_graph_caller)
309 __ftrace_graph_caller
310 ENDPROC(ftrace_graph_caller)
311 #endif
313 .purgem mcount_enter
314 .purgem mcount_get_lr
315 .purgem mcount_exit
317 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
318 .globl return_to_handler
319 return_to_handler:
320 stmdb sp!, {r0-r3}
321 mov r0, fp @ frame pointer
322 bl ftrace_return_to_handler
323 mov lr, r0 @ r0 has real ret addr
324 ldmia sp!, {r0-r3}
325 mov pc, lr
326 #endif
328 ENTRY(ftrace_stub)
329 .Lftrace_stub:
330 mov pc, lr
331 ENDPROC(ftrace_stub)
333 #endif /* CONFIG_FUNCTION_TRACER */
335 /*=============================================================================
336 * SWI handler
337 *-----------------------------------------------------------------------------
338 */
340 .align 5
341 ENTRY(vector_swi)
342 sub sp, sp, #S_FRAME_SIZE
343 stmia sp, {r0 - r12} @ Calling r0 - r12
344 ARM( add r8, sp, #S_PC )
345 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
346 THUMB( mov r8, sp )
347 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
348 mrs r8, spsr @ called from non-FIQ mode, so ok.
349 str lr, [sp, #S_PC] @ Save calling PC
350 str r8, [sp, #S_PSR] @ Save CPSR
351 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
352 zero_fp
354 /*
355 * Get the system call number.
356 */
358 #if defined(CONFIG_OABI_COMPAT)
360 /*
361 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
362 * value to determine if it is an EABI or an old ABI call.
363 */
364 #ifdef CONFIG_ARM_THUMB
365 tst r8, #PSR_T_BIT
366 movne r10, #0 @ no thumb OABI emulation
367 ldreq r10, [lr, #-4] @ get SWI instruction
368 #else
369 ldr r10, [lr, #-4] @ get SWI instruction
370 #endif
371 #ifdef CONFIG_CPU_ENDIAN_BE8
372 rev r10, r10 @ little endian instruction
373 #endif
375 #elif defined(CONFIG_AEABI)
377 /*
378 * Pure EABI user space always put syscall number into scno (r7).
379 */
380 #elif defined(CONFIG_ARM_THUMB)
381 /* Legacy ABI only, possibly thumb mode. */
382 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
383 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
384 ldreq scno, [lr, #-4]
386 #else
387 /* Legacy ABI only. */
388 ldr scno, [lr, #-4] @ get SWI instruction
389 #endif
391 #ifdef CONFIG_ALIGNMENT_TRAP
392 ldr ip, __cr_alignment
393 ldr ip, [ip]
394 mcr p15, 0, ip, c1, c0 @ update control register
395 #endif
396 enable_irq
398 get_thread_info tsk
399 adr tbl, sys_call_table @ load syscall table pointer
401 #if defined(CONFIG_OABI_COMPAT)
402 /*
403 * If the swi argument is zero, this is an EABI call and we do nothing.
404 *
405 * If this is an old ABI call, get the syscall number into scno and
406 * get the old ABI syscall table address.
407 */
408 bics r10, r10, #0xff000000
409 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
410 ldrne tbl, =sys_oabi_call_table
411 #elif !defined(CONFIG_AEABI)
412 bic scno, scno, #0xff000000 @ mask off SWI op-code
413 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
414 #endif
416 local_restart:
417 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
418 stmdb sp!, {r4, r5} @ push fifth and sixth args
420 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
421 bne __sys_trace
423 cmp scno, #NR_syscalls @ check upper syscall limit
424 adr lr, BSYM(ret_fast_syscall) @ return address
425 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
427 add r1, sp, #S_OFF
428 2: mov why, #0 @ no longer a real syscall
429 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
430 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
431 bcs arm_syscall
432 b sys_ni_syscall @ not private func
433 ENDPROC(vector_swi)
435 /*
436 * This is the really slow path. We're going to be doing
437 * context switches, and waiting for our parent to respond.
438 */
439 __sys_trace:
440 mov r1, scno
441 add r0, sp, #S_OFF
442 bl syscall_trace_enter
444 adr lr, BSYM(__sys_trace_return) @ return address
445 mov scno, r0 @ syscall number (possibly new)
446 add r1, sp, #S_R0 + S_OFF @ pointer to regs
447 cmp scno, #NR_syscalls @ check upper syscall limit
448 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
449 stmccia sp, {r4, r5} @ and update the stack args
450 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
451 cmp scno, #-1 @ skip the syscall?
452 bne 2b
453 add sp, sp, #S_OFF @ restore stack
454 b ret_slow_syscall
456 __sys_trace_return:
457 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
458 mov r0, sp
459 bl syscall_trace_exit
460 b ret_slow_syscall
462 .align 5
463 #ifdef CONFIG_ALIGNMENT_TRAP
464 .type __cr_alignment, #object
465 __cr_alignment:
466 .word cr_alignment
467 #endif
468 .ltorg
470 /*
471 * This is the syscall table declaration for native ABI syscalls.
472 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
473 */
474 #define ABI(native, compat) native
475 #ifdef CONFIG_AEABI
476 #define OBSOLETE(syscall) sys_ni_syscall
477 #else
478 #define OBSOLETE(syscall) syscall
479 #endif
481 .type sys_call_table, #object
482 ENTRY(sys_call_table)
483 #include "calls.S"
484 #undef ABI
485 #undef OBSOLETE
487 /*============================================================================
488 * Special system call wrappers
489 */
490 @ r0 = syscall number
491 @ r8 = syscall table
492 sys_syscall:
493 bic scno, r0, #__NR_OABI_SYSCALL_BASE
494 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
495 cmpne scno, #NR_syscalls @ check range
496 stmloia sp, {r5, r6} @ shuffle args
497 movlo r0, r1
498 movlo r1, r2
499 movlo r2, r3
500 movlo r3, r4
501 ldrlo pc, [tbl, scno, lsl #2]
502 b sys_ni_syscall
503 ENDPROC(sys_syscall)
505 sys_sigreturn_wrapper:
506 add r0, sp, #S_OFF
507 mov why, #0 @ prevent syscall restart handling
508 b sys_sigreturn
509 ENDPROC(sys_sigreturn_wrapper)
511 sys_rt_sigreturn_wrapper:
512 add r0, sp, #S_OFF
513 mov why, #0 @ prevent syscall restart handling
514 b sys_rt_sigreturn
515 ENDPROC(sys_rt_sigreturn_wrapper)
517 sys_sigaltstack_wrapper:
518 ldr r2, [sp, #S_OFF + S_SP]
519 b do_sigaltstack
520 ENDPROC(sys_sigaltstack_wrapper)
522 sys_statfs64_wrapper:
523 teq r1, #88
524 moveq r1, #84
525 b sys_statfs64
526 ENDPROC(sys_statfs64_wrapper)
528 sys_fstatfs64_wrapper:
529 teq r1, #88
530 moveq r1, #84
531 b sys_fstatfs64
532 ENDPROC(sys_fstatfs64_wrapper)
534 /*
535 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
536 * offset, we return EINVAL.
537 */
538 sys_mmap2:
539 #if PAGE_SHIFT > 12
540 tst r5, #PGOFF_MASK
541 moveq r5, r5, lsr #PAGE_SHIFT - 12
542 streq r5, [sp, #4]
543 beq sys_mmap_pgoff
544 mov r0, #-EINVAL
545 mov pc, lr
546 #else
547 str r5, [sp, #4]
548 b sys_mmap_pgoff
549 #endif
550 ENDPROC(sys_mmap2)
552 #ifdef CONFIG_OABI_COMPAT
554 /*
555 * These are syscalls with argument register differences
556 */
558 sys_oabi_pread64:
559 stmia sp, {r3, r4}
560 b sys_pread64
561 ENDPROC(sys_oabi_pread64)
563 sys_oabi_pwrite64:
564 stmia sp, {r3, r4}
565 b sys_pwrite64
566 ENDPROC(sys_oabi_pwrite64)
568 sys_oabi_truncate64:
569 mov r3, r2
570 mov r2, r1
571 b sys_truncate64
572 ENDPROC(sys_oabi_truncate64)
574 sys_oabi_ftruncate64:
575 mov r3, r2
576 mov r2, r1
577 b sys_ftruncate64
578 ENDPROC(sys_oabi_ftruncate64)
580 sys_oabi_readahead:
581 str r3, [sp]
582 mov r3, r2
583 mov r2, r1
584 b sys_readahead
585 ENDPROC(sys_oabi_readahead)
587 /*
588 * Let's declare a second syscall table for old ABI binaries
589 * using the compatibility syscall entries.
590 */
591 #define ABI(native, compat) compat
592 #define OBSOLETE(syscall) syscall
594 .type sys_oabi_call_table, #object
595 ENTRY(sys_oabi_call_table)
596 #include "calls.S"
597 #undef ABI
598 #undef OBSOLETE
600 #endif