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/unistd.h>
12 #include <asm/ftrace.h>
13 #include <mach/entry-macro.S>
14 #include <asm/unwind.h>
16 #include "entry-header.S"
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
28 disable_irq @ disable interrupts
29 ldr r1, [tsk, #TI_FLAGS]
30 tst r1, #_TIF_WORK_MASK
32 #if defined(CONFIG_IRQSOFF_TRACER)
36 /* perform architecture specific actions before user return */
37 arch_ret_to_user r1, lr
39 restore_user_regs fast = 1, offset = S_OFF
43 * Ok, we need to do extra processing, enter the slow path.
46 str r0, [sp, #S_R0+S_OFF]! @ returned r0
48 tst r1, #_TIF_NEED_RESCHED
50 tst r1, #_TIF_SIGPENDING|_TIF_NOTIFY_RESUME
53 mov r2, why @ 'syscall'
54 tst r1, #_TIF_SIGPENDING @ delivering a signal?
55 movne why, #0 @ prevent further restarts
57 b ret_slow_syscall @ Check work again
62 * "slow" syscall return path. "why" tells us if this was a real syscall.
66 disable_irq @ disable interrupts
67 ENTRY(ret_to_user_from_irq)
68 ldr r1, [tsk, #TI_FLAGS]
69 tst r1, #_TIF_WORK_MASK
72 #if defined(CONFIG_IRQSOFF_TRACER)
75 /* perform architecture specific actions before user return */
76 arch_ret_to_user r1, lr
78 restore_user_regs fast = 0, offset = 0
79 ENDPROC(ret_to_user_from_irq)
83 * This is how we return from a fork.
88 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
90 tst r1, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
93 mov r0, #1 @ trace exit [IP = 1]
96 ENDPROC(ret_from_fork)
99 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
102 #define CALL(x) .long x
104 #ifdef CONFIG_FUNCTION_TRACER
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.
110 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
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.
119 * push {fp, ip, lr, pc}
122 * With EABI, these frame pointers are not available unless -mapcs-frame is
123 * specified, and if building as Thumb-2, not even then.
125 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
126 * with call sites like:
131 * With these compilers, frame pointers are not necessary.
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
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).
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.
152 .macro mcount_adjust_addr rd, rn
153 bic \rd, \rn, #1 @ clear the Thumb bit if present
154 sub \rd, \rd, #MCOUNT_INSN_SIZE
157 .macro __mcount suffix
159 ldr r0, =ftrace_trace_function
161 adr r0, .Lftrace_stub
165 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
166 ldr r1, =ftrace_graph_return
169 bne ftrace_graph_caller\suffix
171 ldr r1, =ftrace_graph_entry
173 ldr r0, =ftrace_graph_entry_stub
175 bne ftrace_graph_caller\suffix
180 1: mcount_get_lr r1 @ lr of instrumented func
181 mcount_adjust_addr r0, lr @ instrumented function
187 .macro __ftrace_caller suffix
190 mcount_get_lr r1 @ lr of instrumented func
191 mcount_adjust_addr r0, lr @ instrumented function
193 .globl ftrace_call\suffix
197 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
198 .globl ftrace_graph_call\suffix
199 ftrace_graph_call\suffix:
206 .macro __ftrace_graph_caller
207 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
208 #ifdef CONFIG_DYNAMIC_FTRACE
209 @ called from __ftrace_caller, saved in mcount_enter
210 ldr r1, [sp, #16] @ instrumented routine (func)
211 mcount_adjust_addr r1, r1
213 @ called from __mcount, untouched in lr
214 mcount_adjust_addr r1, lr @ instrumented routine (func)
216 mov r2, fp @ frame pointer
217 bl prepare_ftrace_return
221 #ifdef CONFIG_OLD_MCOUNT
227 stmdb sp!, {r0-r3, lr}
230 .macro mcount_get_lr reg
236 ldmia sp!, {r0-r3, pc}
240 #ifdef CONFIG_DYNAMIC_FTRACE
249 #ifdef CONFIG_DYNAMIC_FTRACE
250 ENTRY(ftrace_caller_old)
252 ENDPROC(ftrace_caller_old)
255 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
256 ENTRY(ftrace_graph_caller_old)
257 __ftrace_graph_caller
258 ENDPROC(ftrace_graph_caller_old)
262 .purgem mcount_get_lr
271 stmdb sp!, {r0-r3, lr}
274 .macro mcount_get_lr reg
279 ldmia sp!, {r0-r3, ip, lr}
283 ENTRY(__gnu_mcount_nc)
284 #ifdef CONFIG_DYNAMIC_FTRACE
291 ENDPROC(__gnu_mcount_nc)
293 #ifdef CONFIG_DYNAMIC_FTRACE
296 ENDPROC(ftrace_caller)
299 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
300 ENTRY(ftrace_graph_caller)
301 __ftrace_graph_caller
302 ENDPROC(ftrace_graph_caller)
306 .purgem mcount_get_lr
309 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
310 .globl return_to_handler
313 mov r0, fp @ frame pointer
314 bl ftrace_return_to_handler
315 mov lr, r0 @ r0 has real ret addr
325 #endif /* CONFIG_FUNCTION_TRACER */
327 /*=============================================================================
329 *-----------------------------------------------------------------------------
332 /* If we're optimising for StrongARM the resulting code won't
333 run on an ARM7 and we can save a couple of instructions.
335 #ifdef CONFIG_CPU_ARM710
336 #define A710(code...) code
338 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr
340 add sp, sp, #S_FRAME_SIZE
343 #define A710(code...)
348 sub sp, sp, #S_FRAME_SIZE
349 stmia sp, {r0 - r12} @ Calling r0 - r12
350 ARM( add r8, sp, #S_PC )
351 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
353 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
354 mrs r8, spsr @ called from non-FIQ mode, so ok.
355 str lr, [sp, #S_PC] @ Save calling PC
356 str r8, [sp, #S_PSR] @ Save CPSR
357 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
361 * Get the system call number.
364 #if defined(CONFIG_OABI_COMPAT)
367 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
368 * value to determine if it is an EABI or an old ABI call.
370 #ifdef CONFIG_ARM_THUMB
372 movne r10, #0 @ no thumb OABI emulation
373 ldreq r10, [lr, #-4] @ get SWI instruction
375 ldr r10, [lr, #-4] @ get SWI instruction
376 A710( and ip, r10, #0x0f000000 @ check for SWI )
377 A710( teq ip, #0x0f000000 )
378 A710( bne .Larm710bug )
380 #ifdef CONFIG_CPU_ENDIAN_BE8
381 rev r10, r10 @ little endian instruction
384 #elif defined(CONFIG_AEABI)
387 * Pure EABI user space always put syscall number into scno (r7).
389 A710( ldr ip, [lr, #-4] @ get SWI instruction )
390 A710( and ip, ip, #0x0f000000 @ check for SWI )
391 A710( teq ip, #0x0f000000 )
392 A710( bne .Larm710bug )
394 #elif defined(CONFIG_ARM_THUMB)
396 /* Legacy ABI only, possibly thumb mode. */
397 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
398 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
399 ldreq scno, [lr, #-4]
403 /* Legacy ABI only. */
404 ldr scno, [lr, #-4] @ get SWI instruction
405 A710( and ip, scno, #0x0f000000 @ check for SWI )
406 A710( teq ip, #0x0f000000 )
407 A710( bne .Larm710bug )
411 #ifdef CONFIG_ALIGNMENT_TRAP
412 ldr ip, __cr_alignment
414 mcr p15, 0, ip, c1, c0 @ update control register
419 adr tbl, sys_call_table @ load syscall table pointer
421 #if defined(CONFIG_OABI_COMPAT)
423 * If the swi argument is zero, this is an EABI call and we do nothing.
425 * If this is an old ABI call, get the syscall number into scno and
426 * get the old ABI syscall table address.
428 bics r10, r10, #0xff000000
429 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
430 ldrne tbl, =sys_oabi_call_table
431 #elif !defined(CONFIG_AEABI)
432 bic scno, scno, #0xff000000 @ mask off SWI op-code
433 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
436 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
437 stmdb sp!, {r4, r5} @ push fifth and sixth args
439 #ifdef CONFIG_SECCOMP
440 tst r10, #_TIF_SECCOMP
443 bl __secure_computing
444 add r0, sp, #S_R0 + S_OFF @ pointer to regs
445 ldmia r0, {r0 - r3} @ have to reload r0 - r3
449 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
452 cmp scno, #NR_syscalls @ check upper syscall limit
453 adr lr, BSYM(ret_fast_syscall) @ return address
454 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
457 2: mov why, #0 @ no longer a real syscall
458 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
459 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
461 b sys_ni_syscall @ not private func
465 * This is the really slow path. We're going to be doing
466 * context switches, and waiting for our parent to respond.
471 mov r0, #0 @ trace entry [IP = 0]
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 - r3} @ have to reload r0 - r3
479 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
483 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
486 mov r0, #1 @ trace exit [IP = 1]
491 #ifdef CONFIG_ALIGNMENT_TRAP
492 .type __cr_alignment, #object
499 * This is the syscall table declaration for native ABI syscalls.
500 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
502 #define ABI(native, compat) native
504 #define OBSOLETE(syscall) sys_ni_syscall
506 #define OBSOLETE(syscall) syscall
509 .type sys_call_table, #object
510 ENTRY(sys_call_table)
515 /*============================================================================
516 * Special system call wrappers
518 @ r0 = syscall number
521 bic scno, r0, #__NR_OABI_SYSCALL_BASE
522 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
523 cmpne scno, #NR_syscalls @ check range
524 stmloia sp, {r5, r6} @ shuffle args
529 ldrlo pc, [tbl, scno, lsl #2]
536 ENDPROC(sys_fork_wrapper)
541 ENDPROC(sys_vfork_wrapper)
546 ENDPROC(sys_execve_wrapper)
552 ENDPROC(sys_clone_wrapper)
554 sys_sigreturn_wrapper:
556 mov why, #0 @ prevent syscall restart handling
558 ENDPROC(sys_sigreturn_wrapper)
560 sys_rt_sigreturn_wrapper:
562 mov why, #0 @ prevent syscall restart handling
564 ENDPROC(sys_rt_sigreturn_wrapper)
566 sys_sigaltstack_wrapper:
567 ldr r2, [sp, #S_OFF + S_SP]
569 ENDPROC(sys_sigaltstack_wrapper)
571 sys_statfs64_wrapper:
575 ENDPROC(sys_statfs64_wrapper)
577 sys_fstatfs64_wrapper:
581 ENDPROC(sys_fstatfs64_wrapper)
584 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
585 * offset, we return EINVAL.
590 moveq r5, r5, lsr #PAGE_SHIFT - 12
601 #ifdef CONFIG_OABI_COMPAT
604 * These are syscalls with argument register differences
610 ENDPROC(sys_oabi_pread64)
615 ENDPROC(sys_oabi_pwrite64)
621 ENDPROC(sys_oabi_truncate64)
623 sys_oabi_ftruncate64:
627 ENDPROC(sys_oabi_ftruncate64)
634 ENDPROC(sys_oabi_readahead)
637 * Let's declare a second syscall table for old ABI binaries
638 * using the compatibility syscall entries.
640 #define ABI(native, compat) compat
641 #define OBSOLETE(syscall) syscall
643 .type sys_oabi_call_table, #object
644 ENTRY(sys_oabi_call_table)