Loading...
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
11#include <asm/unistd.h>
12#include <asm/ftrace.h>
13#include <asm/unwind.h>
14
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
21
22#include "entry-header.S"
23
24
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 */
31ret_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
41
42 /* perform architecture specific actions before user return */
43 arch_ret_to_user r1, lr
44
45 restore_user_regs fast = 1, offset = S_OFF
46 UNWIND(.fnend )
47
48/*
49 * Ok, we need to do extra processing, enter the slow path.
50 */
51fast_work_pending:
52 str r0, [sp, #S_R0+S_OFF]! @ returned r0
53work_pending:
54 tst r1, #_TIF_NEED_RESCHED
55 bne work_resched
56 /*
57 * TIF_SIGPENDING or TIF_NOTIFY_RESUME must've been set if we got here
58 */
59 ldr r2, [sp, #S_PSR]
60 mov r0, sp @ 'regs'
61 tst r2, #15 @ are we returning to user mode?
62 bne no_work_pending @ no? just leave, then...
63 mov r2, why @ 'syscall'
64 tst r1, #_TIF_SIGPENDING @ delivering a signal?
65 movne why, #0 @ prevent further restarts
66 bl do_notify_resume
67 b ret_slow_syscall @ Check work again
68
69work_resched:
70 bl schedule
71/*
72 * "slow" syscall return path. "why" tells us if this was a real syscall.
73 */
74ENTRY(ret_to_user)
75ret_slow_syscall:
76 disable_irq @ disable interrupts
77ENTRY(ret_to_user_from_irq)
78 ldr r1, [tsk, #TI_FLAGS]
79 tst r1, #_TIF_WORK_MASK
80 bne work_pending
81no_work_pending:
82#if defined(CONFIG_IRQSOFF_TRACER)
83 asm_trace_hardirqs_on
84#endif
85 /* perform architecture specific actions before user return */
86 arch_ret_to_user r1, lr
87
88 restore_user_regs fast = 0, offset = 0
89ENDPROC(ret_to_user_from_irq)
90ENDPROC(ret_to_user)
91
92/*
93 * This is how we return from a fork.
94 */
95ENTRY(ret_from_fork)
96 bl schedule_tail
97 get_thread_info tsk
98 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
99 mov why, #1
100 tst r1, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
101 beq ret_slow_syscall
102 mov r1, sp
103 mov r0, #1 @ trace exit [IP = 1]
104 bl syscall_trace
105 b ret_slow_syscall
106ENDPROC(ret_from_fork)
107
108 .equ NR_syscalls,0
109#define CALL(x) .equ NR_syscalls,NR_syscalls+1
110#include "calls.S"
111#undef CALL
112#define CALL(x) .long x
113
114#ifdef CONFIG_FUNCTION_TRACER
115/*
116 * When compiling with -pg, gcc inserts a call to the mcount routine at the
117 * start of every function. In mcount, apart from the function's address (in
118 * lr), we need to get hold of the function's caller's address.
119 *
120 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
121 *
122 * bl mcount
123 *
124 * These versions have the limitation that in order for the mcount routine to
125 * be able to determine the function's caller's address, an APCS-style frame
126 * pointer (which is set up with something like the code below) is required.
127 *
128 * mov ip, sp
129 * push {fp, ip, lr, pc}
130 * sub fp, ip, #4
131 *
132 * With EABI, these frame pointers are not available unless -mapcs-frame is
133 * specified, and if building as Thumb-2, not even then.
134 *
135 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
136 * with call sites like:
137 *
138 * push {lr}
139 * bl __gnu_mcount_nc
140 *
141 * With these compilers, frame pointers are not necessary.
142 *
143 * mcount can be thought of as a function called in the middle of a subroutine
144 * call. As such, it needs to be transparent for both the caller and the
145 * callee: the original lr needs to be restored when leaving mcount, and no
146 * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
147 * clobber the ip register. This is OK because the ARM calling convention
148 * allows it to be clobbered in subroutines and doesn't use it to hold
149 * parameters.)
150 *
151 * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
152 * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
153 * arch/arm/kernel/ftrace.c).
154 */
155
156#ifndef CONFIG_OLD_MCOUNT
157#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
158#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
159#endif
160#endif
161
162.macro mcount_adjust_addr rd, rn
163 bic \rd, \rn, #1 @ clear the Thumb bit if present
164 sub \rd, \rd, #MCOUNT_INSN_SIZE
165.endm
166
167.macro __mcount suffix
168 mcount_enter
169 ldr r0, =ftrace_trace_function
170 ldr r2, [r0]
171 adr r0, .Lftrace_stub
172 cmp r0, r2
173 bne 1f
174
175#ifdef CONFIG_FUNCTION_GRAPH_TRACER
176 ldr r1, =ftrace_graph_return
177 ldr r2, [r1]
178 cmp r0, r2
179 bne ftrace_graph_caller\suffix
180
181 ldr r1, =ftrace_graph_entry
182 ldr r2, [r1]
183 ldr r0, =ftrace_graph_entry_stub
184 cmp r0, r2
185 bne ftrace_graph_caller\suffix
186#endif
187
188 mcount_exit
189
1901: mcount_get_lr r1 @ lr of instrumented func
191 mcount_adjust_addr r0, lr @ instrumented function
192 adr lr, BSYM(2f)
193 mov pc, r2
1942: mcount_exit
195.endm
196
197.macro __ftrace_caller suffix
198 mcount_enter
199
200 mcount_get_lr r1 @ lr of instrumented func
201 mcount_adjust_addr r0, lr @ instrumented function
202
203 .globl ftrace_call\suffix
204ftrace_call\suffix:
205 bl ftrace_stub
206
207#ifdef CONFIG_FUNCTION_GRAPH_TRACER
208 .globl ftrace_graph_call\suffix
209ftrace_graph_call\suffix:
210 mov r0, r0
211#endif
212
213 mcount_exit
214.endm
215
216.macro __ftrace_graph_caller
217 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
218#ifdef CONFIG_DYNAMIC_FTRACE
219 @ called from __ftrace_caller, saved in mcount_enter
220 ldr r1, [sp, #16] @ instrumented routine (func)
221 mcount_adjust_addr r1, r1
222#else
223 @ called from __mcount, untouched in lr
224 mcount_adjust_addr r1, lr @ instrumented routine (func)
225#endif
226 mov r2, fp @ frame pointer
227 bl prepare_ftrace_return
228 mcount_exit
229.endm
230
231#ifdef CONFIG_OLD_MCOUNT
232/*
233 * mcount
234 */
235
236.macro mcount_enter
237 stmdb sp!, {r0-r3, lr}
238.endm
239
240.macro mcount_get_lr reg
241 ldr \reg, [fp, #-4]
242.endm
243
244.macro mcount_exit
245 ldr lr, [fp, #-4]
246 ldmia sp!, {r0-r3, pc}
247.endm
248
249ENTRY(mcount)
250#ifdef CONFIG_DYNAMIC_FTRACE
251 stmdb sp!, {lr}
252 ldr lr, [fp, #-4]
253 ldmia sp!, {pc}
254#else
255 __mcount _old
256#endif
257ENDPROC(mcount)
258
259#ifdef CONFIG_DYNAMIC_FTRACE
260ENTRY(ftrace_caller_old)
261 __ftrace_caller _old
262ENDPROC(ftrace_caller_old)
263#endif
264
265#ifdef CONFIG_FUNCTION_GRAPH_TRACER
266ENTRY(ftrace_graph_caller_old)
267 __ftrace_graph_caller
268ENDPROC(ftrace_graph_caller_old)
269#endif
270
271.purgem mcount_enter
272.purgem mcount_get_lr
273.purgem mcount_exit
274#endif
275
276/*
277 * __gnu_mcount_nc
278 */
279
280.macro mcount_enter
281 stmdb sp!, {r0-r3, lr}
282.endm
283
284.macro mcount_get_lr reg
285 ldr \reg, [sp, #20]
286.endm
287
288.macro mcount_exit
289 ldmia sp!, {r0-r3, ip, lr}
290 mov pc, ip
291.endm
292
293ENTRY(__gnu_mcount_nc)
294#ifdef CONFIG_DYNAMIC_FTRACE
295 mov ip, lr
296 ldmia sp!, {lr}
297 mov pc, ip
298#else
299 __mcount
300#endif
301ENDPROC(__gnu_mcount_nc)
302
303#ifdef CONFIG_DYNAMIC_FTRACE
304ENTRY(ftrace_caller)
305 __ftrace_caller
306ENDPROC(ftrace_caller)
307#endif
308
309#ifdef CONFIG_FUNCTION_GRAPH_TRACER
310ENTRY(ftrace_graph_caller)
311 __ftrace_graph_caller
312ENDPROC(ftrace_graph_caller)
313#endif
314
315.purgem mcount_enter
316.purgem mcount_get_lr
317.purgem mcount_exit
318
319#ifdef CONFIG_FUNCTION_GRAPH_TRACER
320 .globl return_to_handler
321return_to_handler:
322 stmdb sp!, {r0-r3}
323 mov r0, fp @ frame pointer
324 bl ftrace_return_to_handler
325 mov lr, r0 @ r0 has real ret addr
326 ldmia sp!, {r0-r3}
327 mov pc, lr
328#endif
329
330ENTRY(ftrace_stub)
331.Lftrace_stub:
332 mov pc, lr
333ENDPROC(ftrace_stub)
334
335#endif /* CONFIG_FUNCTION_TRACER */
336
337/*=============================================================================
338 * SWI handler
339 *-----------------------------------------------------------------------------
340 */
341
342 .align 5
343ENTRY(vector_swi)
344 sub sp, sp, #S_FRAME_SIZE
345 stmia sp, {r0 - r12} @ Calling r0 - r12
346 ARM( add r8, sp, #S_PC )
347 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
348 THUMB( mov r8, sp )
349 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
350 mrs r8, spsr @ called from non-FIQ mode, so ok.
351 str lr, [sp, #S_PC] @ Save calling PC
352 str r8, [sp, #S_PSR] @ Save CPSR
353 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
354 zero_fp
355
356 /*
357 * Get the system call number.
358 */
359
360#if defined(CONFIG_OABI_COMPAT)
361
362 /*
363 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
364 * value to determine if it is an EABI or an old ABI call.
365 */
366#ifdef CONFIG_ARM_THUMB
367 tst r8, #PSR_T_BIT
368 movne r10, #0 @ no thumb OABI emulation
369 ldreq r10, [lr, #-4] @ get SWI instruction
370#else
371 ldr r10, [lr, #-4] @ get SWI instruction
372#endif
373#ifdef CONFIG_CPU_ENDIAN_BE8
374 rev r10, r10 @ little endian instruction
375#endif
376
377#elif defined(CONFIG_AEABI)
378
379 /*
380 * Pure EABI user space always put syscall number into scno (r7).
381 */
382#elif defined(CONFIG_ARM_THUMB)
383 /* Legacy ABI only, possibly thumb mode. */
384 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
385 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
386 ldreq scno, [lr, #-4]
387
388#else
389 /* Legacy ABI only. */
390 ldr scno, [lr, #-4] @ get SWI instruction
391#endif
392
393#ifdef CONFIG_ALIGNMENT_TRAP
394 ldr ip, __cr_alignment
395 ldr ip, [ip]
396 mcr p15, 0, ip, c1, c0 @ update control register
397#endif
398 enable_irq
399
400 get_thread_info tsk
401 adr tbl, sys_call_table @ load syscall table pointer
402
403#if defined(CONFIG_OABI_COMPAT)
404 /*
405 * If the swi argument is zero, this is an EABI call and we do nothing.
406 *
407 * If this is an old ABI call, get the syscall number into scno and
408 * get the old ABI syscall table address.
409 */
410 bics r10, r10, #0xff000000
411 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
412 ldrne tbl, =sys_oabi_call_table
413#elif !defined(CONFIG_AEABI)
414 bic scno, scno, #0xff000000 @ mask off SWI op-code
415 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
416#endif
417
418 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
419 stmdb sp!, {r4, r5} @ push fifth and sixth args
420
421#ifdef CONFIG_SECCOMP
422 tst r10, #_TIF_SECCOMP
423 beq 1f
424 mov r0, scno
425 bl __secure_computing
426 add r0, sp, #S_R0 + S_OFF @ pointer to regs
427 ldmia r0, {r0 - r3} @ have to reload r0 - r3
4281:
429#endif
430
431 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
432 bne __sys_trace
433
434 cmp scno, #NR_syscalls @ check upper syscall limit
435 adr lr, BSYM(ret_fast_syscall) @ return address
436 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
437
438 add r1, sp, #S_OFF
4392: mov why, #0 @ no longer a real syscall
440 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
441 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
442 bcs arm_syscall
443 b sys_ni_syscall @ not private func
444ENDPROC(vector_swi)
445
446 /*
447 * This is the really slow path. We're going to be doing
448 * context switches, and waiting for our parent to respond.
449 */
450__sys_trace:
451 mov r2, scno
452 add r1, sp, #S_OFF
453 mov r0, #0 @ trace entry [IP = 0]
454 bl syscall_trace
455
456 adr lr, BSYM(__sys_trace_return) @ return address
457 mov scno, r0 @ syscall number (possibly new)
458 add r1, sp, #S_R0 + S_OFF @ pointer to regs
459 cmp scno, #NR_syscalls @ check upper syscall limit
460 ldmccia r1, {r0 - r3} @ have to reload r0 - r3
461 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
462 b 2b
463
464__sys_trace_return:
465 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
466 mov r2, scno
467 mov r1, sp
468 mov r0, #1 @ trace exit [IP = 1]
469 bl syscall_trace
470 b ret_slow_syscall
471
472 .align 5
473#ifdef CONFIG_ALIGNMENT_TRAP
474 .type __cr_alignment, #object
475__cr_alignment:
476 .word cr_alignment
477#endif
478 .ltorg
479
480/*
481 * This is the syscall table declaration for native ABI syscalls.
482 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
483 */
484#define ABI(native, compat) native
485#ifdef CONFIG_AEABI
486#define OBSOLETE(syscall) sys_ni_syscall
487#else
488#define OBSOLETE(syscall) syscall
489#endif
490
491 .type sys_call_table, #object
492ENTRY(sys_call_table)
493#include "calls.S"
494#undef ABI
495#undef OBSOLETE
496
497/*============================================================================
498 * Special system call wrappers
499 */
500@ r0 = syscall number
501@ r8 = syscall table
502sys_syscall:
503 bic scno, r0, #__NR_OABI_SYSCALL_BASE
504 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
505 cmpne scno, #NR_syscalls @ check range
506 stmloia sp, {r5, r6} @ shuffle args
507 movlo r0, r1
508 movlo r1, r2
509 movlo r2, r3
510 movlo r3, r4
511 ldrlo pc, [tbl, scno, lsl #2]
512 b sys_ni_syscall
513ENDPROC(sys_syscall)
514
515sys_fork_wrapper:
516 add r0, sp, #S_OFF
517 b sys_fork
518ENDPROC(sys_fork_wrapper)
519
520sys_vfork_wrapper:
521 add r0, sp, #S_OFF
522 b sys_vfork
523ENDPROC(sys_vfork_wrapper)
524
525sys_execve_wrapper:
526 add r3, sp, #S_OFF
527 b sys_execve
528ENDPROC(sys_execve_wrapper)
529
530sys_clone_wrapper:
531 add ip, sp, #S_OFF
532 str ip, [sp, #4]
533 b sys_clone
534ENDPROC(sys_clone_wrapper)
535
536sys_sigreturn_wrapper:
537 add r0, sp, #S_OFF
538 mov why, #0 @ prevent syscall restart handling
539 b sys_sigreturn
540ENDPROC(sys_sigreturn_wrapper)
541
542sys_rt_sigreturn_wrapper:
543 add r0, sp, #S_OFF
544 mov why, #0 @ prevent syscall restart handling
545 b sys_rt_sigreturn
546ENDPROC(sys_rt_sigreturn_wrapper)
547
548sys_sigaltstack_wrapper:
549 ldr r2, [sp, #S_OFF + S_SP]
550 b do_sigaltstack
551ENDPROC(sys_sigaltstack_wrapper)
552
553sys_statfs64_wrapper:
554 teq r1, #88
555 moveq r1, #84
556 b sys_statfs64
557ENDPROC(sys_statfs64_wrapper)
558
559sys_fstatfs64_wrapper:
560 teq r1, #88
561 moveq r1, #84
562 b sys_fstatfs64
563ENDPROC(sys_fstatfs64_wrapper)
564
565/*
566 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
567 * offset, we return EINVAL.
568 */
569sys_mmap2:
570#if PAGE_SHIFT > 12
571 tst r5, #PGOFF_MASK
572 moveq r5, r5, lsr #PAGE_SHIFT - 12
573 streq r5, [sp, #4]
574 beq sys_mmap_pgoff
575 mov r0, #-EINVAL
576 mov pc, lr
577#else
578 str r5, [sp, #4]
579 b sys_mmap_pgoff
580#endif
581ENDPROC(sys_mmap2)
582
583#ifdef CONFIG_OABI_COMPAT
584
585/*
586 * These are syscalls with argument register differences
587 */
588
589sys_oabi_pread64:
590 stmia sp, {r3, r4}
591 b sys_pread64
592ENDPROC(sys_oabi_pread64)
593
594sys_oabi_pwrite64:
595 stmia sp, {r3, r4}
596 b sys_pwrite64
597ENDPROC(sys_oabi_pwrite64)
598
599sys_oabi_truncate64:
600 mov r3, r2
601 mov r2, r1
602 b sys_truncate64
603ENDPROC(sys_oabi_truncate64)
604
605sys_oabi_ftruncate64:
606 mov r3, r2
607 mov r2, r1
608 b sys_ftruncate64
609ENDPROC(sys_oabi_ftruncate64)
610
611sys_oabi_readahead:
612 str r3, [sp]
613 mov r3, r2
614 mov r2, r1
615 b sys_readahead
616ENDPROC(sys_oabi_readahead)
617
618/*
619 * Let's declare a second syscall table for old ABI binaries
620 * using the compatibility syscall entries.
621 */
622#define ABI(native, compat) compat
623#define OBSOLETE(syscall) syscall
624
625 .type sys_oabi_call_table, #object
626ENTRY(sys_oabi_call_table)
627#include "calls.S"
628#undef ABI
629#undef OBSOLETE
630
631#endif
632
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
11#include <asm/unistd.h>
12#include <asm/ftrace.h>
13#include <mach/entry-macro.S>
14#include <asm/unwind.h>
15
16#include "entry-header.S"
17
18
19 .align 5
20/*
21 * This is the fast syscall return path. We do as little as
22 * possible here, and this includes saving r0 back into the SVC
23 * stack.
24 */
25ret_fast_syscall:
26 UNWIND(.fnstart )
27 UNWIND(.cantunwind )
28 disable_irq @ disable interrupts
29 ldr r1, [tsk, #TI_FLAGS]
30 tst r1, #_TIF_WORK_MASK
31 bne fast_work_pending
32#if defined(CONFIG_IRQSOFF_TRACER)
33 asm_trace_hardirqs_on
34#endif
35
36 /* perform architecture specific actions before user return */
37 arch_ret_to_user r1, lr
38
39 restore_user_regs fast = 1, offset = S_OFF
40 UNWIND(.fnend )
41
42/*
43 * Ok, we need to do extra processing, enter the slow path.
44 */
45fast_work_pending:
46 str r0, [sp, #S_R0+S_OFF]! @ returned r0
47work_pending:
48 tst r1, #_TIF_NEED_RESCHED
49 bne work_resched
50 tst r1, #_TIF_SIGPENDING|_TIF_NOTIFY_RESUME
51 beq no_work_pending
52 mov r0, sp @ 'regs'
53 mov r2, why @ 'syscall'
54 tst r1, #_TIF_SIGPENDING @ delivering a signal?
55 movne why, #0 @ prevent further restarts
56 bl do_notify_resume
57 b ret_slow_syscall @ Check work again
58
59work_resched:
60 bl schedule
61/*
62 * "slow" syscall return path. "why" tells us if this was a real syscall.
63 */
64ENTRY(ret_to_user)
65ret_slow_syscall:
66 disable_irq @ disable interrupts
67ENTRY(ret_to_user_from_irq)
68 ldr r1, [tsk, #TI_FLAGS]
69 tst r1, #_TIF_WORK_MASK
70 bne work_pending
71no_work_pending:
72#if defined(CONFIG_IRQSOFF_TRACER)
73 asm_trace_hardirqs_on
74#endif
75 /* perform architecture specific actions before user return */
76 arch_ret_to_user r1, lr
77
78 restore_user_regs fast = 0, offset = 0
79ENDPROC(ret_to_user_from_irq)
80ENDPROC(ret_to_user)
81
82/*
83 * This is how we return from a fork.
84 */
85ENTRY(ret_from_fork)
86 bl schedule_tail
87 get_thread_info tsk
88 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
89 mov why, #1
90 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
91 beq ret_slow_syscall
92 mov r1, sp
93 mov r0, #1 @ trace exit [IP = 1]
94 bl syscall_trace
95 b ret_slow_syscall
96ENDPROC(ret_from_fork)
97
98 .equ NR_syscalls,0
99#define CALL(x) .equ NR_syscalls,NR_syscalls+1
100#include "calls.S"
101#undef CALL
102#define CALL(x) .long x
103
104#ifdef CONFIG_FUNCTION_TRACER
105/*
106 * When compiling with -pg, gcc inserts a call to the mcount routine at the
107 * start of every function. In mcount, apart from the function's address (in
108 * lr), we need to get hold of the function's caller's address.
109 *
110 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
111 *
112 * bl mcount
113 *
114 * These versions have the limitation that in order for the mcount routine to
115 * be able to determine the function's caller's address, an APCS-style frame
116 * pointer (which is set up with something like the code below) is required.
117 *
118 * mov ip, sp
119 * push {fp, ip, lr, pc}
120 * sub fp, ip, #4
121 *
122 * With EABI, these frame pointers are not available unless -mapcs-frame is
123 * specified, and if building as Thumb-2, not even then.
124 *
125 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
126 * with call sites like:
127 *
128 * push {lr}
129 * bl __gnu_mcount_nc
130 *
131 * With these compilers, frame pointers are not necessary.
132 *
133 * mcount can be thought of as a function called in the middle of a subroutine
134 * call. As such, it needs to be transparent for both the caller and the
135 * callee: the original lr needs to be restored when leaving mcount, and no
136 * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
137 * clobber the ip register. This is OK because the ARM calling convention
138 * allows it to be clobbered in subroutines and doesn't use it to hold
139 * parameters.)
140 *
141 * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
142 * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
143 * arch/arm/kernel/ftrace.c).
144 */
145
146#ifndef CONFIG_OLD_MCOUNT
147#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
148#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
149#endif
150#endif
151
152.macro __mcount suffix
153 mcount_enter
154 ldr r0, =ftrace_trace_function
155 ldr r2, [r0]
156 adr r0, .Lftrace_stub
157 cmp r0, r2
158 bne 1f
159
160#ifdef CONFIG_FUNCTION_GRAPH_TRACER
161 ldr r1, =ftrace_graph_return
162 ldr r2, [r1]
163 cmp r0, r2
164 bne ftrace_graph_caller\suffix
165
166 ldr r1, =ftrace_graph_entry
167 ldr r2, [r1]
168 ldr r0, =ftrace_graph_entry_stub
169 cmp r0, r2
170 bne ftrace_graph_caller\suffix
171#endif
172
173 mcount_exit
174
1751: mcount_get_lr r1 @ lr of instrumented func
176 mov r0, lr @ instrumented function
177 sub r0, r0, #MCOUNT_INSN_SIZE
178 adr lr, BSYM(2f)
179 mov pc, r2
1802: mcount_exit
181.endm
182
183.macro __ftrace_caller suffix
184 mcount_enter
185
186 mcount_get_lr r1 @ lr of instrumented func
187 mov r0, lr @ instrumented function
188 sub r0, r0, #MCOUNT_INSN_SIZE
189
190 .globl ftrace_call\suffix
191ftrace_call\suffix:
192 bl ftrace_stub
193
194#ifdef CONFIG_FUNCTION_GRAPH_TRACER
195 .globl ftrace_graph_call\suffix
196ftrace_graph_call\suffix:
197 mov r0, r0
198#endif
199
200 mcount_exit
201.endm
202
203.macro __ftrace_graph_caller
204 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
205#ifdef CONFIG_DYNAMIC_FTRACE
206 @ called from __ftrace_caller, saved in mcount_enter
207 ldr r1, [sp, #16] @ instrumented routine (func)
208#else
209 @ called from __mcount, untouched in lr
210 mov r1, lr @ instrumented routine (func)
211#endif
212 sub r1, r1, #MCOUNT_INSN_SIZE
213 mov r2, fp @ frame pointer
214 bl prepare_ftrace_return
215 mcount_exit
216.endm
217
218#ifdef CONFIG_OLD_MCOUNT
219/*
220 * mcount
221 */
222
223.macro mcount_enter
224 stmdb sp!, {r0-r3, lr}
225.endm
226
227.macro mcount_get_lr reg
228 ldr \reg, [fp, #-4]
229.endm
230
231.macro mcount_exit
232 ldr lr, [fp, #-4]
233 ldmia sp!, {r0-r3, pc}
234.endm
235
236ENTRY(mcount)
237#ifdef CONFIG_DYNAMIC_FTRACE
238 stmdb sp!, {lr}
239 ldr lr, [fp, #-4]
240 ldmia sp!, {pc}
241#else
242 __mcount _old
243#endif
244ENDPROC(mcount)
245
246#ifdef CONFIG_DYNAMIC_FTRACE
247ENTRY(ftrace_caller_old)
248 __ftrace_caller _old
249ENDPROC(ftrace_caller_old)
250#endif
251
252#ifdef CONFIG_FUNCTION_GRAPH_TRACER
253ENTRY(ftrace_graph_caller_old)
254 __ftrace_graph_caller
255ENDPROC(ftrace_graph_caller_old)
256#endif
257
258.purgem mcount_enter
259.purgem mcount_get_lr
260.purgem mcount_exit
261#endif
262
263/*
264 * __gnu_mcount_nc
265 */
266
267.macro mcount_enter
268 stmdb sp!, {r0-r3, lr}
269.endm
270
271.macro mcount_get_lr reg
272 ldr \reg, [sp, #20]
273.endm
274
275.macro mcount_exit
276 ldmia sp!, {r0-r3, ip, lr}
277 mov pc, ip
278.endm
279
280ENTRY(__gnu_mcount_nc)
281#ifdef CONFIG_DYNAMIC_FTRACE
282 mov ip, lr
283 ldmia sp!, {lr}
284 mov pc, ip
285#else
286 __mcount
287#endif
288ENDPROC(__gnu_mcount_nc)
289
290#ifdef CONFIG_DYNAMIC_FTRACE
291ENTRY(ftrace_caller)
292 __ftrace_caller
293ENDPROC(ftrace_caller)
294#endif
295
296#ifdef CONFIG_FUNCTION_GRAPH_TRACER
297ENTRY(ftrace_graph_caller)
298 __ftrace_graph_caller
299ENDPROC(ftrace_graph_caller)
300#endif
301
302.purgem mcount_enter
303.purgem mcount_get_lr
304.purgem mcount_exit
305
306#ifdef CONFIG_FUNCTION_GRAPH_TRACER
307 .globl return_to_handler
308return_to_handler:
309 stmdb sp!, {r0-r3}
310 mov r0, fp @ frame pointer
311 bl ftrace_return_to_handler
312 mov lr, r0 @ r0 has real ret addr
313 ldmia sp!, {r0-r3}
314 mov pc, lr
315#endif
316
317ENTRY(ftrace_stub)
318.Lftrace_stub:
319 mov pc, lr
320ENDPROC(ftrace_stub)
321
322#endif /* CONFIG_FUNCTION_TRACER */
323
324/*=============================================================================
325 * SWI handler
326 *-----------------------------------------------------------------------------
327 */
328
329 /* If we're optimising for StrongARM the resulting code won't
330 run on an ARM7 and we can save a couple of instructions.
331 --pb */
332#ifdef CONFIG_CPU_ARM710
333#define A710(code...) code
334.Larm710bug:
335 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr
336 mov r0, r0
337 add sp, sp, #S_FRAME_SIZE
338 subs pc, lr, #4
339#else
340#define A710(code...)
341#endif
342
343 .align 5
344ENTRY(vector_swi)
345 sub sp, sp, #S_FRAME_SIZE
346 stmia sp, {r0 - r12} @ Calling r0 - r12
347 ARM( add r8, sp, #S_PC )
348 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
349 THUMB( mov r8, sp )
350 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
351 mrs r8, spsr @ called from non-FIQ mode, so ok.
352 str lr, [sp, #S_PC] @ Save calling PC
353 str r8, [sp, #S_PSR] @ Save CPSR
354 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
355 zero_fp
356
357 /*
358 * Get the system call number.
359 */
360
361#if defined(CONFIG_OABI_COMPAT)
362
363 /*
364 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
365 * value to determine if it is an EABI or an old ABI call.
366 */
367#ifdef CONFIG_ARM_THUMB
368 tst r8, #PSR_T_BIT
369 movne r10, #0 @ no thumb OABI emulation
370 ldreq r10, [lr, #-4] @ get SWI instruction
371#else
372 ldr r10, [lr, #-4] @ get SWI instruction
373 A710( and ip, r10, #0x0f000000 @ check for SWI )
374 A710( teq ip, #0x0f000000 )
375 A710( bne .Larm710bug )
376#endif
377#ifdef CONFIG_CPU_ENDIAN_BE8
378 rev r10, r10 @ little endian instruction
379#endif
380
381#elif defined(CONFIG_AEABI)
382
383 /*
384 * Pure EABI user space always put syscall number into scno (r7).
385 */
386 A710( ldr ip, [lr, #-4] @ get SWI instruction )
387 A710( and ip, ip, #0x0f000000 @ check for SWI )
388 A710( teq ip, #0x0f000000 )
389 A710( bne .Larm710bug )
390
391#elif defined(CONFIG_ARM_THUMB)
392
393 /* Legacy ABI only, possibly thumb mode. */
394 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
395 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
396 ldreq scno, [lr, #-4]
397
398#else
399
400 /* Legacy ABI only. */
401 ldr scno, [lr, #-4] @ get SWI instruction
402 A710( and ip, scno, #0x0f000000 @ check for SWI )
403 A710( teq ip, #0x0f000000 )
404 A710( bne .Larm710bug )
405
406#endif
407
408#ifdef CONFIG_ALIGNMENT_TRAP
409 ldr ip, __cr_alignment
410 ldr ip, [ip]
411 mcr p15, 0, ip, c1, c0 @ update control register
412#endif
413 enable_irq
414
415 get_thread_info tsk
416 adr tbl, sys_call_table @ load syscall table pointer
417
418#if defined(CONFIG_OABI_COMPAT)
419 /*
420 * If the swi argument is zero, this is an EABI call and we do nothing.
421 *
422 * If this is an old ABI call, get the syscall number into scno and
423 * get the old ABI syscall table address.
424 */
425 bics r10, r10, #0xff000000
426 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
427 ldrne tbl, =sys_oabi_call_table
428#elif !defined(CONFIG_AEABI)
429 bic scno, scno, #0xff000000 @ mask off SWI op-code
430 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
431#endif
432
433 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
434 stmdb sp!, {r4, r5} @ push fifth and sixth args
435
436#ifdef CONFIG_SECCOMP
437 tst r10, #_TIF_SECCOMP
438 beq 1f
439 mov r0, scno
440 bl __secure_computing
441 add r0, sp, #S_R0 + S_OFF @ pointer to regs
442 ldmia r0, {r0 - r3} @ have to reload r0 - r3
4431:
444#endif
445
446 tst r10, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
447 bne __sys_trace
448
449 cmp scno, #NR_syscalls @ check upper syscall limit
450 adr lr, BSYM(ret_fast_syscall) @ return address
451 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
452
453 add r1, sp, #S_OFF
4542: mov why, #0 @ no longer a real syscall
455 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
456 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
457 bcs arm_syscall
458 b sys_ni_syscall @ not private func
459ENDPROC(vector_swi)
460
461 /*
462 * This is the really slow path. We're going to be doing
463 * context switches, and waiting for our parent to respond.
464 */
465__sys_trace:
466 mov r2, scno
467 add r1, sp, #S_OFF
468 mov r0, #0 @ trace entry [IP = 0]
469 bl syscall_trace
470
471 adr lr, BSYM(__sys_trace_return) @ return address
472 mov scno, r0 @ syscall number (possibly new)
473 add r1, sp, #S_R0 + S_OFF @ pointer to regs
474 cmp scno, #NR_syscalls @ check upper syscall limit
475 ldmccia r1, {r0 - r3} @ have to reload r0 - r3
476 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
477 b 2b
478
479__sys_trace_return:
480 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
481 mov r2, scno
482 mov r1, sp
483 mov r0, #1 @ trace exit [IP = 1]
484 bl syscall_trace
485 b ret_slow_syscall
486
487 .align 5
488#ifdef CONFIG_ALIGNMENT_TRAP
489 .type __cr_alignment, #object
490__cr_alignment:
491 .word cr_alignment
492#endif
493 .ltorg
494
495/*
496 * This is the syscall table declaration for native ABI syscalls.
497 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
498 */
499#define ABI(native, compat) native
500#ifdef CONFIG_AEABI
501#define OBSOLETE(syscall) sys_ni_syscall
502#else
503#define OBSOLETE(syscall) syscall
504#endif
505
506 .type sys_call_table, #object
507ENTRY(sys_call_table)
508#include "calls.S"
509#undef ABI
510#undef OBSOLETE
511
512/*============================================================================
513 * Special system call wrappers
514 */
515@ r0 = syscall number
516@ r8 = syscall table
517sys_syscall:
518 bic scno, r0, #__NR_OABI_SYSCALL_BASE
519 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
520 cmpne scno, #NR_syscalls @ check range
521 stmloia sp, {r5, r6} @ shuffle args
522 movlo r0, r1
523 movlo r1, r2
524 movlo r2, r3
525 movlo r3, r4
526 ldrlo pc, [tbl, scno, lsl #2]
527 b sys_ni_syscall
528ENDPROC(sys_syscall)
529
530sys_fork_wrapper:
531 add r0, sp, #S_OFF
532 b sys_fork
533ENDPROC(sys_fork_wrapper)
534
535sys_vfork_wrapper:
536 add r0, sp, #S_OFF
537 b sys_vfork
538ENDPROC(sys_vfork_wrapper)
539
540sys_execve_wrapper:
541 add r3, sp, #S_OFF
542 b sys_execve
543ENDPROC(sys_execve_wrapper)
544
545sys_clone_wrapper:
546 add ip, sp, #S_OFF
547 str ip, [sp, #4]
548 b sys_clone
549ENDPROC(sys_clone_wrapper)
550
551sys_sigreturn_wrapper:
552 add r0, sp, #S_OFF
553 mov why, #0 @ prevent syscall restart handling
554 b sys_sigreturn
555ENDPROC(sys_sigreturn_wrapper)
556
557sys_rt_sigreturn_wrapper:
558 add r0, sp, #S_OFF
559 mov why, #0 @ prevent syscall restart handling
560 b sys_rt_sigreturn
561ENDPROC(sys_rt_sigreturn_wrapper)
562
563sys_sigaltstack_wrapper:
564 ldr r2, [sp, #S_OFF + S_SP]
565 b do_sigaltstack
566ENDPROC(sys_sigaltstack_wrapper)
567
568sys_statfs64_wrapper:
569 teq r1, #88
570 moveq r1, #84
571 b sys_statfs64
572ENDPROC(sys_statfs64_wrapper)
573
574sys_fstatfs64_wrapper:
575 teq r1, #88
576 moveq r1, #84
577 b sys_fstatfs64
578ENDPROC(sys_fstatfs64_wrapper)
579
580/*
581 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
582 * offset, we return EINVAL.
583 */
584sys_mmap2:
585#if PAGE_SHIFT > 12
586 tst r5, #PGOFF_MASK
587 moveq r5, r5, lsr #PAGE_SHIFT - 12
588 streq r5, [sp, #4]
589 beq sys_mmap_pgoff
590 mov r0, #-EINVAL
591 mov pc, lr
592#else
593 str r5, [sp, #4]
594 b sys_mmap_pgoff
595#endif
596ENDPROC(sys_mmap2)
597
598#ifdef CONFIG_OABI_COMPAT
599
600/*
601 * These are syscalls with argument register differences
602 */
603
604sys_oabi_pread64:
605 stmia sp, {r3, r4}
606 b sys_pread64
607ENDPROC(sys_oabi_pread64)
608
609sys_oabi_pwrite64:
610 stmia sp, {r3, r4}
611 b sys_pwrite64
612ENDPROC(sys_oabi_pwrite64)
613
614sys_oabi_truncate64:
615 mov r3, r2
616 mov r2, r1
617 b sys_truncate64
618ENDPROC(sys_oabi_truncate64)
619
620sys_oabi_ftruncate64:
621 mov r3, r2
622 mov r2, r1
623 b sys_ftruncate64
624ENDPROC(sys_oabi_ftruncate64)
625
626sys_oabi_readahead:
627 str r3, [sp]
628 mov r3, r2
629 mov r2, r1
630 b sys_readahead
631ENDPROC(sys_oabi_readahead)
632
633/*
634 * Let's declare a second syscall table for old ABI binaries
635 * using the compatibility syscall entries.
636 */
637#define ABI(native, compat) compat
638#define OBSOLETE(syscall) syscall
639
640 .type sys_oabi_call_table, #object
641ENTRY(sys_oabi_call_table)
642#include "calls.S"
643#undef ABI
644#undef OBSOLETE
645
646#endif
647