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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
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 asm_trace_hardirqs_on
39
40 /* perform architecture specific actions before user return */
41 arch_ret_to_user r1, lr
42 ct_user_enter
43
44 restore_user_regs fast = 1, offset = S_OFF
45 UNWIND(.fnend )
46
47/*
48 * Ok, we need to do extra processing, enter the slow path.
49 */
50fast_work_pending:
51 str r0, [sp, #S_R0+S_OFF]! @ returned r0
52work_pending:
53 mov r0, sp @ 'regs'
54 mov r2, why @ 'syscall'
55 bl do_work_pending
56 cmp r0, #0
57 beq no_work_pending
58 movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
59 ldmia sp, {r0 - r6} @ have to reload r0 - r6
60 b local_restart @ ... and off we go
61
62/*
63 * "slow" syscall return path. "why" tells us if this was a real syscall.
64 */
65ENTRY(ret_to_user)
66ret_slow_syscall:
67 disable_irq @ disable interrupts
68ENTRY(ret_to_user_from_irq)
69 ldr r1, [tsk, #TI_FLAGS]
70 tst r1, #_TIF_WORK_MASK
71 bne work_pending
72no_work_pending:
73 asm_trace_hardirqs_on
74
75 /* perform architecture specific actions before user return */
76 arch_ret_to_user r1, lr
77 ct_user_enter save = 0
78
79 restore_user_regs fast = 0, offset = 0
80ENDPROC(ret_to_user_from_irq)
81ENDPROC(ret_to_user)
82
83/*
84 * This is how we return from a fork.
85 */
86ENTRY(ret_from_fork)
87 bl schedule_tail
88 cmp r5, #0
89 movne r0, r4
90 adrne lr, BSYM(1f)
91 movne pc, r5
921: get_thread_info tsk
93 b ret_slow_syscall
94ENDPROC(ret_from_fork)
95
96 .equ NR_syscalls,0
97#define CALL(x) .equ NR_syscalls,NR_syscalls+1
98#include "calls.S"
99
100/*
101 * Ensure that the system call table is equal to __NR_syscalls,
102 * which is the value the rest of the system sees
103 */
104.ifne NR_syscalls - __NR_syscalls
105.error "__NR_syscalls is not equal to the size of the syscall table"
106.endif
107
108#undef CALL
109#define CALL(x) .long x
110
111#ifdef CONFIG_FUNCTION_TRACER
112/*
113 * When compiling with -pg, gcc inserts a call to the mcount routine at the
114 * start of every function. In mcount, apart from the function's address (in
115 * lr), we need to get hold of the function's caller's address.
116 *
117 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
118 *
119 * bl mcount
120 *
121 * These versions have the limitation that in order for the mcount routine to
122 * be able to determine the function's caller's address, an APCS-style frame
123 * pointer (which is set up with something like the code below) is required.
124 *
125 * mov ip, sp
126 * push {fp, ip, lr, pc}
127 * sub fp, ip, #4
128 *
129 * With EABI, these frame pointers are not available unless -mapcs-frame is
130 * specified, and if building as Thumb-2, not even then.
131 *
132 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
133 * with call sites like:
134 *
135 * push {lr}
136 * bl __gnu_mcount_nc
137 *
138 * With these compilers, frame pointers are not necessary.
139 *
140 * mcount can be thought of as a function called in the middle of a subroutine
141 * call. As such, it needs to be transparent for both the caller and the
142 * callee: the original lr needs to be restored when leaving mcount, and no
143 * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
144 * clobber the ip register. This is OK because the ARM calling convention
145 * allows it to be clobbered in subroutines and doesn't use it to hold
146 * parameters.)
147 *
148 * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
149 * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
150 * arch/arm/kernel/ftrace.c).
151 */
152
153#ifndef CONFIG_OLD_MCOUNT
154#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
155#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
156#endif
157#endif
158
159.macro mcount_adjust_addr rd, rn
160 bic \rd, \rn, #1 @ clear the Thumb bit if present
161 sub \rd, \rd, #MCOUNT_INSN_SIZE
162.endm
163
164.macro __mcount suffix
165 mcount_enter
166 ldr r0, =ftrace_trace_function
167 ldr r2, [r0]
168 adr r0, .Lftrace_stub
169 cmp r0, r2
170 bne 1f
171
172#ifdef CONFIG_FUNCTION_GRAPH_TRACER
173 ldr r1, =ftrace_graph_return
174 ldr r2, [r1]
175 cmp r0, r2
176 bne ftrace_graph_caller\suffix
177
178 ldr r1, =ftrace_graph_entry
179 ldr r2, [r1]
180 ldr r0, =ftrace_graph_entry_stub
181 cmp r0, r2
182 bne ftrace_graph_caller\suffix
183#endif
184
185 mcount_exit
186
1871: mcount_get_lr r1 @ lr of instrumented func
188 mcount_adjust_addr r0, lr @ instrumented function
189 adr lr, BSYM(2f)
190 mov pc, r2
1912: mcount_exit
192.endm
193
194.macro __ftrace_caller suffix
195 mcount_enter
196
197 mcount_get_lr r1 @ lr of instrumented func
198 mcount_adjust_addr r0, lr @ instrumented function
199
200 .globl ftrace_call\suffix
201ftrace_call\suffix:
202 bl ftrace_stub
203
204#ifdef CONFIG_FUNCTION_GRAPH_TRACER
205 .globl ftrace_graph_call\suffix
206ftrace_graph_call\suffix:
207 mov r0, r0
208#endif
209
210 mcount_exit
211.endm
212
213.macro __ftrace_graph_caller
214 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
215#ifdef CONFIG_DYNAMIC_FTRACE
216 @ called from __ftrace_caller, saved in mcount_enter
217 ldr r1, [sp, #16] @ instrumented routine (func)
218 mcount_adjust_addr r1, r1
219#else
220 @ called from __mcount, untouched in lr
221 mcount_adjust_addr r1, lr @ instrumented routine (func)
222#endif
223 mov r2, fp @ frame pointer
224 bl prepare_ftrace_return
225 mcount_exit
226.endm
227
228#ifdef CONFIG_OLD_MCOUNT
229/*
230 * mcount
231 */
232
233.macro mcount_enter
234 stmdb sp!, {r0-r3, lr}
235.endm
236
237.macro mcount_get_lr reg
238 ldr \reg, [fp, #-4]
239.endm
240
241.macro mcount_exit
242 ldr lr, [fp, #-4]
243 ldmia sp!, {r0-r3, pc}
244.endm
245
246ENTRY(mcount)
247#ifdef CONFIG_DYNAMIC_FTRACE
248 stmdb sp!, {lr}
249 ldr lr, [fp, #-4]
250 ldmia sp!, {pc}
251#else
252 __mcount _old
253#endif
254ENDPROC(mcount)
255
256#ifdef CONFIG_DYNAMIC_FTRACE
257ENTRY(ftrace_caller_old)
258 __ftrace_caller _old
259ENDPROC(ftrace_caller_old)
260#endif
261
262#ifdef CONFIG_FUNCTION_GRAPH_TRACER
263ENTRY(ftrace_graph_caller_old)
264 __ftrace_graph_caller
265ENDPROC(ftrace_graph_caller_old)
266#endif
267
268.purgem mcount_enter
269.purgem mcount_get_lr
270.purgem mcount_exit
271#endif
272
273/*
274 * __gnu_mcount_nc
275 */
276
277.macro mcount_enter
278/*
279 * This pad compensates for the push {lr} at the call site. Note that we are
280 * unable to unwind through a function which does not otherwise save its lr.
281 */
282 UNWIND(.pad #4)
283 stmdb sp!, {r0-r3, lr}
284 UNWIND(.save {r0-r3, lr})
285.endm
286
287.macro mcount_get_lr reg
288 ldr \reg, [sp, #20]
289.endm
290
291.macro mcount_exit
292 ldmia sp!, {r0-r3, ip, lr}
293 mov pc, ip
294.endm
295
296ENTRY(__gnu_mcount_nc)
297UNWIND(.fnstart)
298#ifdef CONFIG_DYNAMIC_FTRACE
299 mov ip, lr
300 ldmia sp!, {lr}
301 mov pc, ip
302#else
303 __mcount
304#endif
305UNWIND(.fnend)
306ENDPROC(__gnu_mcount_nc)
307
308#ifdef CONFIG_DYNAMIC_FTRACE
309ENTRY(ftrace_caller)
310UNWIND(.fnstart)
311 __ftrace_caller
312UNWIND(.fnend)
313ENDPROC(ftrace_caller)
314#endif
315
316#ifdef CONFIG_FUNCTION_GRAPH_TRACER
317ENTRY(ftrace_graph_caller)
318UNWIND(.fnstart)
319 __ftrace_graph_caller
320UNWIND(.fnend)
321ENDPROC(ftrace_graph_caller)
322#endif
323
324.purgem mcount_enter
325.purgem mcount_get_lr
326.purgem mcount_exit
327
328#ifdef CONFIG_FUNCTION_GRAPH_TRACER
329 .globl return_to_handler
330return_to_handler:
331 stmdb sp!, {r0-r3}
332 mov r0, fp @ frame pointer
333 bl ftrace_return_to_handler
334 mov lr, r0 @ r0 has real ret addr
335 ldmia sp!, {r0-r3}
336 mov pc, lr
337#endif
338
339ENTRY(ftrace_stub)
340.Lftrace_stub:
341 mov pc, lr
342ENDPROC(ftrace_stub)
343
344#endif /* CONFIG_FUNCTION_TRACER */
345
346/*=============================================================================
347 * SWI handler
348 *-----------------------------------------------------------------------------
349 */
350
351 .align 5
352ENTRY(vector_swi)
353#ifdef CONFIG_CPU_V7M
354 v7m_exception_entry
355#else
356 sub sp, sp, #S_FRAME_SIZE
357 stmia sp, {r0 - r12} @ Calling r0 - r12
358 ARM( add r8, sp, #S_PC )
359 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
360 THUMB( mov r8, sp )
361 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
362 mrs r8, spsr @ called from non-FIQ mode, so ok.
363 str lr, [sp, #S_PC] @ Save calling PC
364 str r8, [sp, #S_PSR] @ Save CPSR
365 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
366#endif
367 zero_fp
368
369#ifdef CONFIG_ALIGNMENT_TRAP
370 ldr ip, __cr_alignment
371 ldr ip, [ip]
372 mcr p15, 0, ip, c1, c0 @ update control register
373#endif
374
375 enable_irq
376 ct_user_exit
377 get_thread_info tsk
378
379 /*
380 * Get the system call number.
381 */
382
383#if defined(CONFIG_OABI_COMPAT)
384
385 /*
386 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
387 * value to determine if it is an EABI or an old ABI call.
388 */
389#ifdef CONFIG_ARM_THUMB
390 tst r8, #PSR_T_BIT
391 movne r10, #0 @ no thumb OABI emulation
392 USER( ldreq r10, [lr, #-4] ) @ get SWI instruction
393#else
394 USER( ldr r10, [lr, #-4] ) @ get SWI instruction
395#endif
396 ARM_BE8(rev r10, r10) @ little endian instruction
397
398#elif defined(CONFIG_AEABI)
399
400 /*
401 * Pure EABI user space always put syscall number into scno (r7).
402 */
403#elif defined(CONFIG_ARM_THUMB)
404 /* Legacy ABI only, possibly thumb mode. */
405 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
406 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
407 USER( ldreq scno, [lr, #-4] )
408
409#else
410 /* Legacy ABI only. */
411 USER( ldr scno, [lr, #-4] ) @ get SWI instruction
412#endif
413
414 adr tbl, sys_call_table @ load syscall table pointer
415
416#if defined(CONFIG_OABI_COMPAT)
417 /*
418 * If the swi argument is zero, this is an EABI call and we do nothing.
419 *
420 * If this is an old ABI call, get the syscall number into scno and
421 * get the old ABI syscall table address.
422 */
423 bics r10, r10, #0xff000000
424 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
425 ldrne tbl, =sys_oabi_call_table
426#elif !defined(CONFIG_AEABI)
427 bic scno, scno, #0xff000000 @ mask off SWI op-code
428 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
429#endif
430
431local_restart:
432 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
433 stmdb sp!, {r4, r5} @ push fifth and sixth args
434
435 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
436 bne __sys_trace
437
438 cmp scno, #NR_syscalls @ check upper syscall limit
439 adr lr, BSYM(ret_fast_syscall) @ return address
440 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
441
442 add r1, sp, #S_OFF
4432: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
444 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
445 bcs arm_syscall
446 mov why, #0 @ no longer a real syscall
447 b sys_ni_syscall @ not private func
448
449#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
450 /*
451 * We failed to handle a fault trying to access the page
452 * containing the swi instruction, but we're not really in a
453 * position to return -EFAULT. Instead, return back to the
454 * instruction and re-enter the user fault handling path trying
455 * to page it in. This will likely result in sending SEGV to the
456 * current task.
457 */
4589001:
459 sub lr, lr, #4
460 str lr, [sp, #S_PC]
461 b ret_fast_syscall
462#endif
463ENDPROC(vector_swi)
464
465 /*
466 * This is the really slow path. We're going to be doing
467 * context switches, and waiting for our parent to respond.
468 */
469__sys_trace:
470 mov r1, scno
471 add r0, sp, #S_OFF
472 bl syscall_trace_enter
473
474 adr lr, BSYM(__sys_trace_return) @ return address
475 mov scno, r0 @ syscall number (possibly new)
476 add r1, sp, #S_R0 + S_OFF @ pointer to regs
477 cmp scno, #NR_syscalls @ check upper syscall limit
478 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
479 stmccia sp, {r4, r5} @ and update the stack args
480 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
481 cmp scno, #-1 @ skip the syscall?
482 bne 2b
483 add sp, sp, #S_OFF @ restore stack
484 b ret_slow_syscall
485
486__sys_trace_return:
487 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
488 mov r0, sp
489 bl syscall_trace_exit
490 b ret_slow_syscall
491
492 .align 5
493#ifdef CONFIG_ALIGNMENT_TRAP
494 .type __cr_alignment, #object
495__cr_alignment:
496 .word cr_alignment
497#endif
498 .ltorg
499
500/*
501 * This is the syscall table declaration for native ABI syscalls.
502 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
503 */
504#define ABI(native, compat) native
505#ifdef CONFIG_AEABI
506#define OBSOLETE(syscall) sys_ni_syscall
507#else
508#define OBSOLETE(syscall) syscall
509#endif
510
511 .type sys_call_table, #object
512ENTRY(sys_call_table)
513#include "calls.S"
514#undef ABI
515#undef OBSOLETE
516
517/*============================================================================
518 * Special system call wrappers
519 */
520@ r0 = syscall number
521@ r8 = syscall table
522sys_syscall:
523 bic scno, r0, #__NR_OABI_SYSCALL_BASE
524 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
525 cmpne scno, #NR_syscalls @ check range
526 stmloia sp, {r5, r6} @ shuffle args
527 movlo r0, r1
528 movlo r1, r2
529 movlo r2, r3
530 movlo r3, r4
531 ldrlo pc, [tbl, scno, lsl #2]
532 b sys_ni_syscall
533ENDPROC(sys_syscall)
534
535sys_sigreturn_wrapper:
536 add r0, sp, #S_OFF
537 mov why, #0 @ prevent syscall restart handling
538 b sys_sigreturn
539ENDPROC(sys_sigreturn_wrapper)
540
541sys_rt_sigreturn_wrapper:
542 add r0, sp, #S_OFF
543 mov why, #0 @ prevent syscall restart handling
544 b sys_rt_sigreturn
545ENDPROC(sys_rt_sigreturn_wrapper)
546
547sys_statfs64_wrapper:
548 teq r1, #88
549 moveq r1, #84
550 b sys_statfs64
551ENDPROC(sys_statfs64_wrapper)
552
553sys_fstatfs64_wrapper:
554 teq r1, #88
555 moveq r1, #84
556 b sys_fstatfs64
557ENDPROC(sys_fstatfs64_wrapper)
558
559/*
560 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
561 * offset, we return EINVAL.
562 */
563sys_mmap2:
564#if PAGE_SHIFT > 12
565 tst r5, #PGOFF_MASK
566 moveq r5, r5, lsr #PAGE_SHIFT - 12
567 streq r5, [sp, #4]
568 beq sys_mmap_pgoff
569 mov r0, #-EINVAL
570 mov pc, lr
571#else
572 str r5, [sp, #4]
573 b sys_mmap_pgoff
574#endif
575ENDPROC(sys_mmap2)
576
577#ifdef CONFIG_OABI_COMPAT
578
579/*
580 * These are syscalls with argument register differences
581 */
582
583sys_oabi_pread64:
584 stmia sp, {r3, r4}
585 b sys_pread64
586ENDPROC(sys_oabi_pread64)
587
588sys_oabi_pwrite64:
589 stmia sp, {r3, r4}
590 b sys_pwrite64
591ENDPROC(sys_oabi_pwrite64)
592
593sys_oabi_truncate64:
594 mov r3, r2
595 mov r2, r1
596 b sys_truncate64
597ENDPROC(sys_oabi_truncate64)
598
599sys_oabi_ftruncate64:
600 mov r3, r2
601 mov r2, r1
602 b sys_ftruncate64
603ENDPROC(sys_oabi_ftruncate64)
604
605sys_oabi_readahead:
606 str r3, [sp]
607 mov r3, r2
608 mov r2, r1
609 b sys_readahead
610ENDPROC(sys_oabi_readahead)
611
612/*
613 * Let's declare a second syscall table for old ABI binaries
614 * using the compatibility syscall entries.
615 */
616#define ABI(native, compat) compat
617#define OBSOLETE(syscall) syscall
618
619 .type sys_oabi_call_table, #object
620ENTRY(sys_oabi_call_table)
621#include "calls.S"
622#undef ABI
623#undef OBSOLETE
624
625#endif
626