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)
94 ENTRY(ret_from_kernel_thread)
99 adr lr, BSYM(1f) @ kernel threads should not exit
104 ENDPROC(ret_from_kernel_thread)
107 * turn a kernel thread into userland process
108 * use: ret_from_kernel_execve(struct pt_regs *normal)
110 ENTRY(ret_from_kernel_execve)
111 mov why, #0 @ not a syscall
112 str why, [r0, #S_R0] @ ... and we want 0 in ->ARM_r0 as well
113 get_thread_info tsk @ thread structure
114 mov sp, r0 @ stack pointer just under pt_regs
116 ENDPROC(ret_from_kernel_execve)
119 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
123 * Ensure that the system call table is equal to __NR_syscalls,
124 * which is the value the rest of the system sees
126 .ifne NR_syscalls - __NR_syscalls
127 .error "__NR_syscalls is not equal to the size of the syscall table"
131 #define CALL(x) .long x
133 #ifdef CONFIG_FUNCTION_TRACER
135 * When compiling with -pg, gcc inserts a call to the mcount routine at the
136 * start of every function. In mcount, apart from the function's address (in
137 * lr), we need to get hold of the function's caller's address.
139 * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
143 * These versions have the limitation that in order for the mcount routine to
144 * be able to determine the function's caller's address, an APCS-style frame
145 * pointer (which is set up with something like the code below) is required.
148 * push {fp, ip, lr, pc}
151 * With EABI, these frame pointers are not available unless -mapcs-frame is
152 * specified, and if building as Thumb-2, not even then.
154 * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
155 * with call sites like:
160 * With these compilers, frame pointers are not necessary.
162 * mcount can be thought of as a function called in the middle of a subroutine
163 * call. As such, it needs to be transparent for both the caller and the
164 * callee: the original lr needs to be restored when leaving mcount, and no
165 * registers should be clobbered. (In the __gnu_mcount_nc implementation, we
166 * clobber the ip register. This is OK because the ARM calling convention
167 * allows it to be clobbered in subroutines and doesn't use it to hold
170 * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
171 * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
172 * arch/arm/kernel/ftrace.c).
175 #ifndef CONFIG_OLD_MCOUNT
176 #if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
177 #error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
181 .macro mcount_adjust_addr rd, rn
182 bic \rd, \rn, #1 @ clear the Thumb bit if present
183 sub \rd, \rd, #MCOUNT_INSN_SIZE
186 .macro __mcount suffix
188 ldr r0, =ftrace_trace_function
190 adr r0, .Lftrace_stub
194 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
195 ldr r1, =ftrace_graph_return
198 bne ftrace_graph_caller\suffix
200 ldr r1, =ftrace_graph_entry
202 ldr r0, =ftrace_graph_entry_stub
204 bne ftrace_graph_caller\suffix
209 1: mcount_get_lr r1 @ lr of instrumented func
210 mcount_adjust_addr r0, lr @ instrumented function
216 .macro __ftrace_caller suffix
219 mcount_get_lr r1 @ lr of instrumented func
220 mcount_adjust_addr r0, lr @ instrumented function
222 .globl ftrace_call\suffix
226 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
227 .globl ftrace_graph_call\suffix
228 ftrace_graph_call\suffix:
235 .macro __ftrace_graph_caller
236 sub r0, fp, #4 @ &lr of instrumented routine (&parent)
237 #ifdef CONFIG_DYNAMIC_FTRACE
238 @ called from __ftrace_caller, saved in mcount_enter
239 ldr r1, [sp, #16] @ instrumented routine (func)
240 mcount_adjust_addr r1, r1
242 @ called from __mcount, untouched in lr
243 mcount_adjust_addr r1, lr @ instrumented routine (func)
245 mov r2, fp @ frame pointer
246 bl prepare_ftrace_return
250 #ifdef CONFIG_OLD_MCOUNT
256 stmdb sp!, {r0-r3, lr}
259 .macro mcount_get_lr reg
265 ldmia sp!, {r0-r3, pc}
269 #ifdef CONFIG_DYNAMIC_FTRACE
278 #ifdef CONFIG_DYNAMIC_FTRACE
279 ENTRY(ftrace_caller_old)
281 ENDPROC(ftrace_caller_old)
284 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
285 ENTRY(ftrace_graph_caller_old)
286 __ftrace_graph_caller
287 ENDPROC(ftrace_graph_caller_old)
291 .purgem mcount_get_lr
300 stmdb sp!, {r0-r3, lr}
303 .macro mcount_get_lr reg
308 ldmia sp!, {r0-r3, ip, lr}
312 ENTRY(__gnu_mcount_nc)
313 #ifdef CONFIG_DYNAMIC_FTRACE
320 ENDPROC(__gnu_mcount_nc)
322 #ifdef CONFIG_DYNAMIC_FTRACE
325 ENDPROC(ftrace_caller)
328 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
329 ENTRY(ftrace_graph_caller)
330 __ftrace_graph_caller
331 ENDPROC(ftrace_graph_caller)
335 .purgem mcount_get_lr
338 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
339 .globl return_to_handler
342 mov r0, fp @ frame pointer
343 bl ftrace_return_to_handler
344 mov lr, r0 @ r0 has real ret addr
354 #endif /* CONFIG_FUNCTION_TRACER */
356 /*=============================================================================
358 *-----------------------------------------------------------------------------
363 sub sp, sp, #S_FRAME_SIZE
364 stmia sp, {r0 - r12} @ Calling r0 - r12
365 ARM( add r8, sp, #S_PC )
366 ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
368 THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
369 mrs r8, spsr @ called from non-FIQ mode, so ok.
370 str lr, [sp, #S_PC] @ Save calling PC
371 str r8, [sp, #S_PSR] @ Save CPSR
372 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
376 * Get the system call number.
379 #if defined(CONFIG_OABI_COMPAT)
382 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
383 * value to determine if it is an EABI or an old ABI call.
385 #ifdef CONFIG_ARM_THUMB
387 movne r10, #0 @ no thumb OABI emulation
388 ldreq r10, [lr, #-4] @ get SWI instruction
390 ldr r10, [lr, #-4] @ get SWI instruction
392 #ifdef CONFIG_CPU_ENDIAN_BE8
393 rev r10, r10 @ little endian instruction
396 #elif defined(CONFIG_AEABI)
399 * Pure EABI user space always put syscall number into scno (r7).
401 #elif defined(CONFIG_ARM_THUMB)
402 /* Legacy ABI only, possibly thumb mode. */
403 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
404 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
405 ldreq scno, [lr, #-4]
408 /* Legacy ABI only. */
409 ldr scno, [lr, #-4] @ get SWI instruction
412 #ifdef CONFIG_ALIGNMENT_TRAP
413 ldr ip, __cr_alignment
415 mcr p15, 0, ip, c1, c0 @ update control register
420 adr tbl, sys_call_table @ load syscall table pointer
422 #if defined(CONFIG_OABI_COMPAT)
424 * If the swi argument is zero, this is an EABI call and we do nothing.
426 * If this is an old ABI call, get the syscall number into scno and
427 * get the old ABI syscall table address.
429 bics r10, r10, #0xff000000
430 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
431 ldrne tbl, =sys_oabi_call_table
432 #elif !defined(CONFIG_AEABI)
433 bic scno, scno, #0xff000000 @ mask off SWI op-code
434 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
438 ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
439 stmdb sp!, {r4, r5} @ push fifth and sixth args
441 #ifdef CONFIG_SECCOMP
442 tst r10, #_TIF_SECCOMP
445 bl __secure_computing
446 add r0, sp, #S_R0 + S_OFF @ pointer to regs
447 ldmia r0, {r0 - r3} @ have to reload r0 - r3
451 tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
454 cmp scno, #NR_syscalls @ check upper syscall limit
455 adr lr, BSYM(ret_fast_syscall) @ return address
456 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
459 2: mov why, #0 @ no longer a real syscall
460 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
461 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
463 b sys_ni_syscall @ not private func
467 * This is the really slow path. We're going to be doing
468 * context switches, and waiting for our parent to respond.
473 bl syscall_trace_enter
475 adr lr, BSYM(__sys_trace_return) @ return address
476 mov scno, r0 @ syscall number (possibly new)
477 add r1, sp, #S_R0 + S_OFF @ pointer to regs
478 cmp scno, #NR_syscalls @ check upper syscall limit
479 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
480 stmccia sp, {r4, r5} @ and update the stack args
481 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
485 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
488 bl syscall_trace_exit
492 #ifdef CONFIG_ALIGNMENT_TRAP
493 .type __cr_alignment, #object
500 * This is the syscall table declaration for native ABI syscalls.
501 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
503 #define ABI(native, compat) native
505 #define OBSOLETE(syscall) sys_ni_syscall
507 #define OBSOLETE(syscall) syscall
510 .type sys_call_table, #object
511 ENTRY(sys_call_table)
516 /*============================================================================
517 * Special system call wrappers
519 @ r0 = syscall number
522 bic scno, r0, #__NR_OABI_SYSCALL_BASE
523 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
524 cmpne scno, #NR_syscalls @ check range
525 stmloia sp, {r5, r6} @ shuffle args
530 ldrlo pc, [tbl, scno, lsl #2]
537 ENDPROC(sys_fork_wrapper)
542 ENDPROC(sys_vfork_wrapper)
548 ENDPROC(sys_clone_wrapper)
550 sys_sigreturn_wrapper:
552 mov why, #0 @ prevent syscall restart handling
554 ENDPROC(sys_sigreturn_wrapper)
556 sys_rt_sigreturn_wrapper:
558 mov why, #0 @ prevent syscall restart handling
560 ENDPROC(sys_rt_sigreturn_wrapper)
562 sys_sigaltstack_wrapper:
563 ldr r2, [sp, #S_OFF + S_SP]
565 ENDPROC(sys_sigaltstack_wrapper)
567 sys_statfs64_wrapper:
571 ENDPROC(sys_statfs64_wrapper)
573 sys_fstatfs64_wrapper:
577 ENDPROC(sys_fstatfs64_wrapper)
580 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
581 * offset, we return EINVAL.
586 moveq r5, r5, lsr #PAGE_SHIFT - 12
597 #ifdef CONFIG_OABI_COMPAT
600 * These are syscalls with argument register differences
606 ENDPROC(sys_oabi_pread64)
611 ENDPROC(sys_oabi_pwrite64)
617 ENDPROC(sys_oabi_truncate64)
619 sys_oabi_ftruncate64:
623 ENDPROC(sys_oabi_ftruncate64)
630 ENDPROC(sys_oabi_readahead)
633 * Let's declare a second syscall table for old ABI binaries
634 * using the compatibility syscall entries.
636 #define ABI(native, compat) compat
637 #define OBSOLETE(syscall) syscall
639 .type sys_oabi_call_table, #object
640 ENTRY(sys_oabi_call_table)