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 <asm/unwind.h>
15 #ifdef CONFIG_NEED_RET_TO_USER
16 #include <mach/entry-macro.S>
18 .macro arch_ret_to_user, tmp1, tmp2
22 #include "entry-header.S"
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
34 disable_irq @ disable interrupts
35 ldr r1, [tsk, #TI_FLAGS]
36 tst r1, #_TIF_WORK_MASK
38 #if defined(CONFIG_IRQSOFF_TRACER)
42 /* perform architecture specific actions before user return */
43 arch_ret_to_user r1, lr
45 restore_user_regs fast = 1, offset = S_OFF
49 * Ok, we need to do extra processing, enter the slow path.
52 str r0, [sp, #S_R0+S_OFF]! @ returned r0
54 tst r1, #_TIF_NEED_RESCHED
56 tst r1, #_TIF_SIGPENDING|_TIF_NOTIFY_RESUME
59 mov r2, why @ 'syscall'
60 tst r1, #_TIF_SIGPENDING @ delivering a signal?
61 movne why, #0 @ prevent further restarts
63 b ret_slow_syscall @ Check work again
68 * "slow" syscall return path. "why" tells us if this was a real syscall.
72 disable_irq @ disable interrupts
73 ENTRY(ret_to_user_from_irq)
74 ldr r1, [tsk, #TI_FLAGS]
75 tst r1, #_TIF_WORK_MASK
78 #if defined(CONFIG_IRQSOFF_TRACER)
81 /* perform architecture specific actions before user return */
82 arch_ret_to_user r1, lr
84 restore_user_regs fast = 0, offset = 0
85 ENDPROC(ret_to_user_from_irq)
89 * This is how we return from a fork.
94 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
96 tst r1, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
99 mov r0, #1 @ trace exit [IP = 1]
102 ENDPROC(ret_from_fork)
105 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
108 #define CALL(x) .long x
110 #ifdef CONFIG_FUNCTION_TRACER
112 * When compiling with -pg, gcc inserts a call to the mcount routine at the
113 * start of every function. In mcount, apart from the function's address (in
114 * lr), we need to get hold of the function's caller's address.
116 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
120 * These versions have the limitation that in order for the mcount routine to
121 * be able to determine the function's caller's address, an APCS-style frame
122 * pointer (which is set up with something like the code below) is required.
125 * push {fp, ip, lr, pc}
128 * With EABI, these frame pointers are not available unless -mapcs-frame is
129 * specified, and if building as Thumb-2, not even then.
131 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
132 * with call sites like:
137 * With these compilers, frame pointers are not necessary.
139 * mcount can be thought of as a function called in the middle of a subroutine
140 * call. As such, it needs to be transparent for both the caller and the
141 * callee: the original lr needs to be restored when leaving mcount, and no
142 * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
143 * clobber the ip register. This is OK because the ARM calling convention
144 * allows it to be clobbered in subroutines and doesn't use it to hold
147 * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
148 * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
149 * arch/arm/kernel/ftrace.c).
152 #ifndef CONFIG_OLD_MCOUNT
153 #if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
154 #error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
158 .macro mcount_adjust_addr rd, rn
159 bic \rd, \rn, #1 @ clear the Thumb bit if present
160 sub \rd, \rd, #MCOUNT_INSN_SIZE
163 .macro __mcount suffix
165 ldr r0, =ftrace_trace_function
167 adr r0, .Lftrace_stub
171 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
172 ldr r1, =ftrace_graph_return
175 bne ftrace_graph_caller\suffix
177 ldr r1, =ftrace_graph_entry
179 ldr r0, =ftrace_graph_entry_stub
181 bne ftrace_graph_caller\suffix
186 1: mcount_get_lr r1 @ lr of instrumented func
187 mcount_adjust_addr r0, lr @ instrumented function
193 .macro __ftrace_caller suffix
196 mcount_get_lr r1 @ lr of instrumented func
197 mcount_adjust_addr r0, lr @ instrumented function
199 .globl ftrace_call\suffix
203 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
204 .globl ftrace_graph_call\suffix
205 ftrace_graph_call\suffix:
212 .macro __ftrace_graph_caller
213 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
214 #ifdef CONFIG_DYNAMIC_FTRACE
215 @ called from __ftrace_caller, saved in mcount_enter
216 ldr r1, [sp, #16] @ instrumented routine (func)
217 mcount_adjust_addr r1, r1
219 @ called from __mcount, untouched in lr
220 mcount_adjust_addr r1, lr @ instrumented routine (func)
222 mov r2, fp @ frame pointer
223 bl prepare_ftrace_return
227 #ifdef CONFIG_OLD_MCOUNT
233 stmdb sp!, {r0-r3, lr}
236 .macro mcount_get_lr reg
242 ldmia sp!, {r0-r3, pc}
246 #ifdef CONFIG_DYNAMIC_FTRACE
255 #ifdef CONFIG_DYNAMIC_FTRACE
256 ENTRY(ftrace_caller_old)
258 ENDPROC(ftrace_caller_old)
261 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
262 ENTRY(ftrace_graph_caller_old)
263 __ftrace_graph_caller
264 ENDPROC(ftrace_graph_caller_old)
268 .purgem mcount_get_lr
277 stmdb sp!, {r0-r3, lr}
280 .macro mcount_get_lr reg
285 ldmia sp!, {r0-r3, ip, lr}
289 ENTRY(__gnu_mcount_nc)
290 #ifdef CONFIG_DYNAMIC_FTRACE
297 ENDPROC(__gnu_mcount_nc)
299 #ifdef CONFIG_DYNAMIC_FTRACE
302 ENDPROC(ftrace_caller)
305 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
306 ENTRY(ftrace_graph_caller)
307 __ftrace_graph_caller
308 ENDPROC(ftrace_graph_caller)
312 .purgem mcount_get_lr
315 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
316 .globl return_to_handler
319 mov r0, fp @ frame pointer
320 bl ftrace_return_to_handler
321 mov lr, r0 @ r0 has real ret addr
331 #endif /* CONFIG_FUNCTION_TRACER */
333 /*=============================================================================
335 *-----------------------------------------------------------------------------
340 sub sp, sp, #S_FRAME_SIZE
341 stmia sp, {r0 - r12} @ Calling r0 - r12
342 ARM( add r8, sp, #S_PC )
343 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
345 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
346 mrs r8, spsr @ called from non-FIQ mode, so ok.
347 str lr, [sp, #S_PC] @ Save calling PC
348 str r8, [sp, #S_PSR] @ Save CPSR
349 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
353 * Get the system call number.
356 #if defined(CONFIG_OABI_COMPAT)
359 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
360 * value to determine if it is an EABI or an old ABI call.
362 #ifdef CONFIG_ARM_THUMB
364 movne r10, #0 @ no thumb OABI emulation
365 ldreq r10, [lr, #-4] @ get SWI instruction
367 ldr r10, [lr, #-4] @ get SWI instruction
369 #ifdef CONFIG_CPU_ENDIAN_BE8
370 rev r10, r10 @ little endian instruction
373 #elif defined(CONFIG_AEABI)
376 * Pure EABI user space always put syscall number into scno (r7).
378 #elif defined(CONFIG_ARM_THUMB)
379 /* Legacy ABI only, possibly thumb mode. */
380 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
381 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
382 ldreq scno, [lr, #-4]
385 /* Legacy ABI only. */
386 ldr scno, [lr, #-4] @ get SWI instruction
389 #ifdef CONFIG_ALIGNMENT_TRAP
390 ldr ip, __cr_alignment
392 mcr p15, 0, ip, c1, c0 @ update control register
397 adr tbl, sys_call_table @ load syscall table pointer
399 #if defined(CONFIG_OABI_COMPAT)
401 * If the swi argument is zero, this is an EABI call and we do nothing.
403 * If this is an old ABI call, get the syscall number into scno and
404 * get the old ABI syscall table address.
406 bics r10, r10, #0xff000000
407 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
408 ldrne tbl, =sys_oabi_call_table
409 #elif !defined(CONFIG_AEABI)
410 bic scno, scno, #0xff000000 @ mask off SWI op-code
411 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
414 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
415 stmdb sp!, {r4, r5} @ push fifth and sixth args
417 #ifdef CONFIG_SECCOMP
418 tst r10, #_TIF_SECCOMP
421 bl __secure_computing
422 add r0, sp, #S_R0 + S_OFF @ pointer to regs
423 ldmia r0, {r0 - r3} @ have to reload r0 - r3
427 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
430 cmp scno, #NR_syscalls @ check upper syscall limit
431 adr lr, BSYM(ret_fast_syscall) @ return address
432 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
435 2: mov why, #0 @ no longer a real syscall
436 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
437 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
439 b sys_ni_syscall @ not private func
443 * This is the really slow path. We're going to be doing
444 * context switches, and waiting for our parent to respond.
449 mov r0, #0 @ trace entry [IP = 0]
452 adr lr, BSYM(__sys_trace_return) @ return address
453 mov scno, r0 @ syscall number (possibly new)
454 add r1, sp, #S_R0 + S_OFF @ pointer to regs
455 cmp scno, #NR_syscalls @ check upper syscall limit
456 ldmccia r1, {r0 - r3} @ have to reload r0 - r3
457 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
461 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
464 mov r0, #1 @ trace exit [IP = 1]
469 #ifdef CONFIG_ALIGNMENT_TRAP
470 .type __cr_alignment, #object
477 * This is the syscall table declaration for native ABI syscalls.
478 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
480 #define ABI(native, compat) native
482 #define OBSOLETE(syscall) sys_ni_syscall
484 #define OBSOLETE(syscall) syscall
487 .type sys_call_table, #object
488 ENTRY(sys_call_table)
493 /*============================================================================
494 * Special system call wrappers
496 @ r0 = syscall number
499 bic scno, r0, #__NR_OABI_SYSCALL_BASE
500 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
501 cmpne scno, #NR_syscalls @ check range
502 stmloia sp, {r5, r6} @ shuffle args
507 ldrlo pc, [tbl, scno, lsl #2]
514 ENDPROC(sys_fork_wrapper)
519 ENDPROC(sys_vfork_wrapper)
524 ENDPROC(sys_execve_wrapper)
530 ENDPROC(sys_clone_wrapper)
532 sys_sigreturn_wrapper:
534 mov why, #0 @ prevent syscall restart handling
536 ENDPROC(sys_sigreturn_wrapper)
538 sys_rt_sigreturn_wrapper:
540 mov why, #0 @ prevent syscall restart handling
542 ENDPROC(sys_rt_sigreturn_wrapper)
544 sys_sigaltstack_wrapper:
545 ldr r2, [sp, #S_OFF + S_SP]
547 ENDPROC(sys_sigaltstack_wrapper)
549 sys_statfs64_wrapper:
553 ENDPROC(sys_statfs64_wrapper)
555 sys_fstatfs64_wrapper:
559 ENDPROC(sys_fstatfs64_wrapper)
562 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
563 * offset, we return EINVAL.
568 moveq r5, r5, lsr #PAGE_SHIFT - 12
579 #ifdef CONFIG_OABI_COMPAT
582 * These are syscalls with argument register differences
588 ENDPROC(sys_oabi_pread64)
593 ENDPROC(sys_oabi_pwrite64)
599 ENDPROC(sys_oabi_truncate64)
601 sys_oabi_ftruncate64:
605 ENDPROC(sys_oabi_ftruncate64)
612 ENDPROC(sys_oabi_readahead)
615 * Let's declare a second syscall table for old ABI binaries
616 * using the compatibility syscall entries.
618 #define ABI(native, compat) compat
619 #define OBSOLETE(syscall) syscall
621 .type sys_oabi_call_table, #object
622 ENTRY(sys_oabi_call_table)