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
55 mov r2, why @ 'syscall'
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
64 * "slow" syscall return path. "why" tells us if this was a real 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
74 #if defined(CONFIG_IRQSOFF_TRACER)
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)
85 * This is how we return from a fork.
92 ENDPROC(ret_from_fork)
95 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
99 * Ensure that the system call table is equal to __NR_syscalls,
100 * which is the value the rest of the system sees
102 .ifne NR_syscalls - __NR_syscalls
103 .error "__NR_syscalls is not equal to the size of the syscall table"
107 #define CALL(x) .long x
109 #ifdef CONFIG_FUNCTION_TRACER
111 * When compiling with -pg, gcc inserts a call to the mcount routine at the
112 * start of every function. In mcount, apart from the function's address (in
113 * lr), we need to get hold of the function's caller's address.
115 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
119 * These versions have the limitation that in order for the mcount routine to
120 * be able to determine the function's caller's address, an APCS-style frame
121 * pointer (which is set up with something like the code below) is required.
124 * push {fp, ip, lr, pc}
127 * With EABI, these frame pointers are not available unless -mapcs-frame is
128 * specified, and if building as Thumb-2, not even then.
130 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
131 * with call sites like:
136 * With these compilers, frame pointers are not necessary.
138 * mcount can be thought of as a function called in the middle of a subroutine
139 * call. As such, it needs to be transparent for both the caller and the
140 * callee: the original lr needs to be restored when leaving mcount, and no
141 * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
142 * clobber the ip register. This is OK because the ARM calling convention
143 * allows it to be clobbered in subroutines and doesn't use it to hold
146 * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
147 * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
148 * arch/arm/kernel/ftrace.c).
151 #ifndef CONFIG_OLD_MCOUNT
152 #if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
153 #error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
157 .macro mcount_adjust_addr rd, rn
158 bic \rd, \rn, #1 @ clear the Thumb bit if present
159 sub \rd, \rd, #MCOUNT_INSN_SIZE
162 .macro __mcount suffix
164 ldr r0, =ftrace_trace_function
166 adr r0, .Lftrace_stub
170 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
171 ldr r1, =ftrace_graph_return
174 bne ftrace_graph_caller\suffix
176 ldr r1, =ftrace_graph_entry
178 ldr r0, =ftrace_graph_entry_stub
180 bne ftrace_graph_caller\suffix
185 1: mcount_get_lr r1 @ lr of instrumented func
186 mcount_adjust_addr r0, lr @ instrumented function
192 .macro __ftrace_caller suffix
195 mcount_get_lr r1 @ lr of instrumented func
196 mcount_adjust_addr r0, lr @ instrumented function
198 .globl ftrace_call\suffix
202 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
203 .globl ftrace_graph_call\suffix
204 ftrace_graph_call\suffix:
211 .macro __ftrace_graph_caller
212 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
213 #ifdef CONFIG_DYNAMIC_FTRACE
214 @ called from __ftrace_caller, saved in mcount_enter
215 ldr r1, [sp, #16] @ instrumented routine (func)
216 mcount_adjust_addr r1, r1
218 @ called from __mcount, untouched in lr
219 mcount_adjust_addr r1, lr @ instrumented routine (func)
221 mov r2, fp @ frame pointer
222 bl prepare_ftrace_return
226 #ifdef CONFIG_OLD_MCOUNT
232 stmdb sp!, {r0-r3, lr}
235 .macro mcount_get_lr reg
241 ldmia sp!, {r0-r3, pc}
245 #ifdef CONFIG_DYNAMIC_FTRACE
254 #ifdef CONFIG_DYNAMIC_FTRACE
255 ENTRY(ftrace_caller_old)
257 ENDPROC(ftrace_caller_old)
260 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
261 ENTRY(ftrace_graph_caller_old)
262 __ftrace_graph_caller
263 ENDPROC(ftrace_graph_caller_old)
267 .purgem mcount_get_lr
276 stmdb sp!, {r0-r3, lr}
279 .macro mcount_get_lr reg
284 ldmia sp!, {r0-r3, ip, lr}
288 ENTRY(__gnu_mcount_nc)
289 #ifdef CONFIG_DYNAMIC_FTRACE
296 ENDPROC(__gnu_mcount_nc)
298 #ifdef CONFIG_DYNAMIC_FTRACE
301 ENDPROC(ftrace_caller)
304 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
305 ENTRY(ftrace_graph_caller)
306 __ftrace_graph_caller
307 ENDPROC(ftrace_graph_caller)
311 .purgem mcount_get_lr
314 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
315 .globl return_to_handler
318 mov r0, fp @ frame pointer
319 bl ftrace_return_to_handler
320 mov lr, r0 @ r0 has real ret addr
330 #endif /* CONFIG_FUNCTION_TRACER */
332 /*=============================================================================
334 *-----------------------------------------------------------------------------
339 sub sp, sp, #S_FRAME_SIZE
340 stmia sp, {r0 - r12} @ Calling r0 - r12
341 ARM( add r8, sp, #S_PC )
342 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
344 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
345 mrs r8, spsr @ called from non-FIQ mode, so ok.
346 str lr, [sp, #S_PC] @ Save calling PC
347 str r8, [sp, #S_PSR] @ Save CPSR
348 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
352 * Get the system call number.
355 #if defined(CONFIG_OABI_COMPAT)
358 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
359 * value to determine if it is an EABI or an old ABI call.
361 #ifdef CONFIG_ARM_THUMB
363 movne r10, #0 @ no thumb OABI emulation
364 ldreq r10, [lr, #-4] @ get SWI instruction
366 ldr r10, [lr, #-4] @ get SWI instruction
368 #ifdef CONFIG_CPU_ENDIAN_BE8
369 rev r10, r10 @ little endian instruction
372 #elif defined(CONFIG_AEABI)
375 * Pure EABI user space always put syscall number into scno (r7).
377 #elif defined(CONFIG_ARM_THUMB)
378 /* Legacy ABI only, possibly thumb mode. */
379 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
380 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
381 ldreq scno, [lr, #-4]
384 /* Legacy ABI only. */
385 ldr scno, [lr, #-4] @ get SWI instruction
388 #ifdef CONFIG_ALIGNMENT_TRAP
389 ldr ip, __cr_alignment
391 mcr p15, 0, ip, c1, c0 @ update control register
396 adr tbl, sys_call_table @ load syscall table pointer
398 #if defined(CONFIG_OABI_COMPAT)
400 * If the swi argument is zero, this is an EABI call and we do nothing.
402 * If this is an old ABI call, get the syscall number into scno and
403 * get the old ABI syscall table address.
405 bics r10, r10, #0xff000000
406 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
407 ldrne tbl, =sys_oabi_call_table
408 #elif !defined(CONFIG_AEABI)
409 bic scno, scno, #0xff000000 @ mask off SWI op-code
410 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 bl syscall_trace_enter
451 adr lr, BSYM(__sys_trace_return) @ return address
452 mov scno, r0 @ syscall number (possibly new)
453 add r1, sp, #S_R0 + S_OFF @ pointer to regs
454 cmp scno, #NR_syscalls @ check upper syscall limit
455 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
456 stmccia sp, {r4, r5} @ and update the stack args
457 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
461 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
464 bl syscall_trace_exit
468 #ifdef CONFIG_ALIGNMENT_TRAP
469 .type __cr_alignment, #object
476 * This is the syscall table declaration for native ABI syscalls.
477 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
479 #define ABI(native, compat) native
481 #define OBSOLETE(syscall) sys_ni_syscall
483 #define OBSOLETE(syscall) syscall
486 .type sys_call_table, #object
487 ENTRY(sys_call_table)
492 /*============================================================================
493 * Special system call wrappers
495 @ r0 = syscall number
498 bic scno, r0, #__NR_OABI_SYSCALL_BASE
499 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
500 cmpne scno, #NR_syscalls @ check range
501 stmloia sp, {r5, r6} @ shuffle args
506 ldrlo pc, [tbl, scno, lsl #2]
513 ENDPROC(sys_fork_wrapper)
518 ENDPROC(sys_vfork_wrapper)
523 ENDPROC(sys_execve_wrapper)
529 ENDPROC(sys_clone_wrapper)
531 sys_sigreturn_wrapper:
533 mov why, #0 @ prevent syscall restart handling
535 ENDPROC(sys_sigreturn_wrapper)
537 sys_rt_sigreturn_wrapper:
539 mov why, #0 @ prevent syscall restart handling
541 ENDPROC(sys_rt_sigreturn_wrapper)
543 sys_sigaltstack_wrapper:
544 ldr r2, [sp, #S_OFF + S_SP]
546 ENDPROC(sys_sigaltstack_wrapper)
548 sys_statfs64_wrapper:
552 ENDPROC(sys_statfs64_wrapper)
554 sys_fstatfs64_wrapper:
558 ENDPROC(sys_fstatfs64_wrapper)
561 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
562 * offset, we return EINVAL.
567 moveq r5, r5, lsr #PAGE_SHIFT - 12
578 #ifdef CONFIG_OABI_COMPAT
581 * These are syscalls with argument register differences
587 ENDPROC(sys_oabi_pread64)
592 ENDPROC(sys_oabi_pwrite64)
598 ENDPROC(sys_oabi_truncate64)
600 sys_oabi_ftruncate64:
604 ENDPROC(sys_oabi_ftruncate64)
611 ENDPROC(sys_oabi_readahead)
614 * Let's declare a second syscall table for old ABI binaries
615 * using the compatibility syscall entries.
617 #define ABI(native, compat) compat
618 #define OBSOLETE(syscall) syscall
620 .type sys_oabi_call_table, #object
621 ENTRY(sys_oabi_call_table)