[deliverable/linux.git] / arch / arm / kernel / entry-common.S

/*
 *  linux/arch/arm/kernel/entry-common.S
 *
 *  Copyright (C) 2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <asm/assembler.h>
#include <asm/unistd.h>
#include <asm/ftrace.h>
#include <asm/unwind.h>

#ifdef CONFIG_NEED_RET_TO_USER
#include <mach/entry-macro.S>
#else
	.macro  arch_ret_to_user, tmp1, tmp2
	.endm
#endif

#include "entry-header.S"


	.align	5
#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
/*
 * This is the fast syscall return path.  We do as little as possible here,
 * such as avoiding writing r0 to the stack.  We only use this path if we
 * have tracing and context tracking disabled - the overheads from those
 * features make this path too inefficient.
 */
ret_fast_syscall:
 UNWIND(.fnstart	)
 UNWIND(.cantunwind	)
	disable_irq_notrace			@ disable interrupts
	ldr	r1, [tsk, #TI_FLAGS]		@ re-check for syscall tracing
	tst	r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
	bne	fast_work_pending

	/* perform architecture specific actions before user return */
	arch_ret_to_user r1, lr

	restore_user_regs fast = 1, offset = S_OFF
 UNWIND(.fnend		)
ENDPROC(ret_fast_syscall)

	/* Ok, we need to do extra processing, enter the slow path. */
fast_work_pending:
	str	r0, [sp, #S_R0+S_OFF]!		@ returned r0
	/* fall through to work_pending */
#else
/*
 * The "replacement" ret_fast_syscall for when tracing or context tracking
 * is enabled.  As we will need to call out to some C functions, we save
 * r0 first to avoid needing to save registers around each C function call.
 */
ret_fast_syscall:
 UNWIND(.fnstart	)
 UNWIND(.cantunwind	)
	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0
	disable_irq_notrace			@ disable interrupts
	ldr	r1, [tsk, #TI_FLAGS]		@ re-check for syscall tracing
	tst	r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
	beq	no_work_pending
 UNWIND(.fnend		)
ENDPROC(ret_fast_syscall)

	/* Slower path - fall through to work_pending */
#endif

	tst	r1, #_TIF_SYSCALL_WORK
	bne	__sys_trace_return_nosave
slow_work_pending:
	mov	r0, sp				@ 'regs'
	mov	r2, why				@ 'syscall'
	bl	do_work_pending
	cmp	r0, #0
	beq	no_work_pending
	movlt	scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
	ldmia	sp, {r0 - r6}			@ have to reload r0 - r6
	b	local_restart			@ ... and off we go
ENDPROC(ret_fast_syscall)

/*
 * "slow" syscall return path.  "why" tells us if this was a real syscall.
 * IRQs may be enabled here, so always disable them.  Note that we use the
 * "notrace" version to avoid calling into the tracing code unnecessarily.
 * do_work_pending() will update this state if necessary.
 */
ENTRY(ret_to_user)
ret_slow_syscall:
	disable_irq_notrace			@ disable interrupts
ENTRY(ret_to_user_from_irq)
	ldr	r1, [tsk, #TI_FLAGS]
	tst	r1, #_TIF_WORK_MASK
	bne	slow_work_pending
no_work_pending:
	asm_trace_hardirqs_on save = 0

	/* perform architecture specific actions before user return */
	arch_ret_to_user r1, lr
	ct_user_enter save = 0

	restore_user_regs fast = 0, offset = 0
ENDPROC(ret_to_user_from_irq)
ENDPROC(ret_to_user)

/*
 * This is how we return from a fork.
 */
ENTRY(ret_from_fork)
	bl	schedule_tail
	cmp	r5, #0
	movne	r0, r4
	badrne	lr, 1f
	retne	r5
1:	get_thread_info tsk
	b	ret_slow_syscall
ENDPROC(ret_from_fork)

	.equ NR_syscalls,0
#define CALL(x) .equ NR_syscalls,NR_syscalls+1
#include "calls.S"

/*
 * Ensure that the system call table is equal to __NR_syscalls,
 * which is the value the rest of the system sees
 */
.ifne NR_syscalls - __NR_syscalls
.error "__NR_syscalls is not equal to the size of the syscall table"
.endif

#undef CALL
#define CALL(x) .long x

/*=============================================================================
 * SWI handler
 *-----------------------------------------------------------------------------
 */

	.align	5
ENTRY(vector_swi)
#ifdef CONFIG_CPU_V7M
	v7m_exception_entry
#else
	sub	sp, sp, #S_FRAME_SIZE
	stmia	sp, {r0 - r12}			@ Calling r0 - r12
 ARM(	add	r8, sp, #S_PC		)
 ARM(	stmdb	r8, {sp, lr}^		)	@ Calling sp, lr
 THUMB(	mov	r8, sp			)
 THUMB(	store_user_sp_lr r8, r10, S_SP	)	@ calling sp, lr
	mrs	r8, spsr			@ called from non-FIQ mode, so ok.
	str	lr, [sp, #S_PC]			@ Save calling PC
	str	r8, [sp, #S_PSR]		@ Save CPSR
	str	r0, [sp, #S_OLD_R0]		@ Save OLD_R0
#endif
	zero_fp
	alignment_trap r10, ip, __cr_alignment
	enable_irq
	ct_user_exit
	get_thread_info tsk

	/*
	 * Get the system call number.
	 */

#if defined(CONFIG_OABI_COMPAT)

	/*
	 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
	 * value to determine if it is an EABI or an old ABI call.
	 */
#ifdef CONFIG_ARM_THUMB
	tst	r8, #PSR_T_BIT
	movne	r10, #0				@ no thumb OABI emulation
 USER(	ldreq	r10, [lr, #-4]		)	@ get SWI instruction
#else
 USER(	ldr	r10, [lr, #-4]		)	@ get SWI instruction
#endif
 ARM_BE8(rev	r10, r10)			@ little endian instruction

#elif defined(CONFIG_AEABI)

	/*
	 * Pure EABI user space always put syscall number into scno (r7).
	 */
#elif defined(CONFIG_ARM_THUMB)
	/* Legacy ABI only, possibly thumb mode. */
	tst	r8, #PSR_T_BIT			@ this is SPSR from save_user_regs
	addne	scno, r7, #__NR_SYSCALL_BASE	@ put OS number in
 USER(	ldreq	scno, [lr, #-4]		)

#else
	/* Legacy ABI only. */
 USER(	ldr	scno, [lr, #-4]		)	@ get SWI instruction
#endif

	uaccess_disable tbl

	adr	tbl, sys_call_table		@ load syscall table pointer

#if defined(CONFIG_OABI_COMPAT)
	/*
	 * If the swi argument is zero, this is an EABI call and we do nothing.
	 *
	 * If this is an old ABI call, get the syscall number into scno and
	 * get the old ABI syscall table address.
	 */
	bics	r10, r10, #0xff000000
	eorne	scno, r10, #__NR_OABI_SYSCALL_BASE
	ldrne	tbl, =sys_oabi_call_table
#elif !defined(CONFIG_AEABI)
	bic	scno, scno, #0xff000000		@ mask off SWI op-code
	eor	scno, scno, #__NR_SYSCALL_BASE	@ check OS number
#endif

local_restart:
	ldr	r10, [tsk, #TI_FLAGS]		@ check for syscall tracing
	stmdb	sp!, {r4, r5}			@ push fifth and sixth args

	tst	r10, #_TIF_SYSCALL_WORK		@ are we tracing syscalls?
	bne	__sys_trace

	cmp	scno, #NR_syscalls		@ check upper syscall limit
	badr	lr, ret_fast_syscall		@ return address
	ldrcc	pc, [tbl, scno, lsl #2]		@ call sys_* routine

	add	r1, sp, #S_OFF
2:	cmp	scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
	eor	r0, scno, #__NR_SYSCALL_BASE	@ put OS number back
	bcs	arm_syscall
	mov	why, #0				@ no longer a real syscall
	b	sys_ni_syscall			@ not private func

#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)
	/*
	 * We failed to handle a fault trying to access the page
	 * containing the swi instruction, but we're not really in a
	 * position to return -EFAULT. Instead, return back to the
	 * instruction and re-enter the user fault handling path trying
	 * to page it in. This will likely result in sending SEGV to the
	 * current task.
	 */
9001:
	sub	lr, lr, #4
	str	lr, [sp, #S_PC]
	b	ret_fast_syscall
#endif
ENDPROC(vector_swi)

	/*
	 * This is the really slow path.  We're going to be doing
	 * context switches, and waiting for our parent to respond.
	 */
__sys_trace:
	mov	r1, scno
	add	r0, sp, #S_OFF
	bl	syscall_trace_enter

	badr	lr, __sys_trace_return		@ return address
	mov	scno, r0			@ syscall number (possibly new)
	add	r1, sp, #S_R0 + S_OFF		@ pointer to regs
	cmp	scno, #NR_syscalls		@ check upper syscall limit
	ldmccia	r1, {r0 - r6}			@ have to reload r0 - r6
	stmccia	sp, {r4, r5}			@ and update the stack args
	ldrcc	pc, [tbl, scno, lsl #2]		@ call sys_* routine
	cmp	scno, #-1			@ skip the syscall?
	bne	2b
	add	sp, sp, #S_OFF			@ restore stack
	b	ret_slow_syscall

__sys_trace_return:
	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0
	mov	r0, sp
	bl	syscall_trace_exit
	b	ret_slow_syscall

__sys_trace_return_nosave:
	enable_irq_notrace
	mov	r0, sp
	bl	syscall_trace_exit
	b	ret_slow_syscall

	.align	5
#ifdef CONFIG_ALIGNMENT_TRAP
	.type	__cr_alignment, #object
__cr_alignment:
	.word	cr_alignment
#endif
	.ltorg

/*
 * This is the syscall table declaration for native ABI syscalls.
 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
 */
#define ABI(native, compat) native
#ifdef CONFIG_AEABI
#define OBSOLETE(syscall) sys_ni_syscall
#else
#define OBSOLETE(syscall) syscall
#endif

	.type	sys_call_table, #object
ENTRY(sys_call_table)
#include "calls.S"
#undef ABI
#undef OBSOLETE

/*============================================================================
 * Special system call wrappers
 */
@ r0 = syscall number
@ r8 = syscall table
sys_syscall:
		bic	scno, r0, #__NR_OABI_SYSCALL_BASE
		cmp	scno, #__NR_syscall - __NR_SYSCALL_BASE
		cmpne	scno, #NR_syscalls	@ check range
		stmloia	sp, {r5, r6}		@ shuffle args
		movlo	r0, r1
		movlo	r1, r2
		movlo	r2, r3
		movlo	r3, r4
		ldrlo	pc, [tbl, scno, lsl #2]
		b	sys_ni_syscall
ENDPROC(sys_syscall)

sys_sigreturn_wrapper:
		add	r0, sp, #S_OFF
		mov	why, #0		@ prevent syscall restart handling
		b	sys_sigreturn
ENDPROC(sys_sigreturn_wrapper)

sys_rt_sigreturn_wrapper:
		add	r0, sp, #S_OFF
		mov	why, #0		@ prevent syscall restart handling
		b	sys_rt_sigreturn
ENDPROC(sys_rt_sigreturn_wrapper)

sys_statfs64_wrapper:
		teq	r1, #88
		moveq	r1, #84
		b	sys_statfs64
ENDPROC(sys_statfs64_wrapper)

sys_fstatfs64_wrapper:
		teq	r1, #88
		moveq	r1, #84
		b	sys_fstatfs64
ENDPROC(sys_fstatfs64_wrapper)

/*
 * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
 * offset, we return EINVAL.
 */
sys_mmap2:
#if PAGE_SHIFT > 12
		tst	r5, #PGOFF_MASK
		moveq	r5, r5, lsr #PAGE_SHIFT - 12
		streq	r5, [sp, #4]
		beq	sys_mmap_pgoff
		mov	r0, #-EINVAL
		ret	lr
#else
		str	r5, [sp, #4]
		b	sys_mmap_pgoff
#endif
ENDPROC(sys_mmap2)

#ifdef CONFIG_OABI_COMPAT

/*
 * These are syscalls with argument register differences
 */

sys_oabi_pread64:
		stmia	sp, {r3, r4}
		b	sys_pread64
ENDPROC(sys_oabi_pread64)

sys_oabi_pwrite64:
		stmia	sp, {r3, r4}
		b	sys_pwrite64
ENDPROC(sys_oabi_pwrite64)

sys_oabi_truncate64:
		mov	r3, r2
		mov	r2, r1
		b	sys_truncate64
ENDPROC(sys_oabi_truncate64)

sys_oabi_ftruncate64:
		mov	r3, r2
		mov	r2, r1
		b	sys_ftruncate64
ENDPROC(sys_oabi_ftruncate64)

sys_oabi_readahead:
		str	r3, [sp]
		mov	r3, r2
		mov	r2, r1
		b	sys_readahead
ENDPROC(sys_oabi_readahead)

/*
 * Let's declare a second syscall table for old ABI binaries
 * using the compatibility syscall entries.
 */
#define ABI(native, compat) compat
#define OBSOLETE(syscall) syscall

	.type	sys_oabi_call_table, #object
ENTRY(sys_oabi_call_table)
#include "calls.S"
#undef ABI
#undef OBSOLETE

#endif
Commit	Line	Data
	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/assembler.h>
	12	#include <asm/unistd.h>
	13	#include <asm/ftrace.h>
	14	#include <asm/unwind.h>
	15
	16	#ifdef CONFIG_NEED_RET_TO_USER
	17	#include <mach/entry-macro.S>
	18	#else
	19	.macro arch_ret_to_user, tmp1, tmp2
	20	.endm
	21	#endif
	22
	23	#include "entry-header.S"
	24
	25
	26	.align 5
	27	#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) \|\| IS_ENABLED(CONFIG_CONTEXT_TRACKING))
	28	/*
	29	* This is the fast syscall return path. We do as little as possible here,
	30	* such as avoiding writing r0 to the stack. We only use this path if we
	31	* have tracing and context tracking disabled - the overheads from those
	32	* features make this path too inefficient.
	33	*/
	34	ret_fast_syscall:
	35	UNWIND(.fnstart )
	36	UNWIND(.cantunwind )
	37	disable_irq_notrace @ disable interrupts
	38	ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
	39	tst r1, #_TIF_SYSCALL_WORK \| _TIF_WORK_MASK
	40	bne fast_work_pending
	41
	42	/* perform architecture specific actions before user return */
	43	arch_ret_to_user r1, lr
	44
	45	restore_user_regs fast = 1, offset = S_OFF
	46	UNWIND(.fnend )
	47	ENDPROC(ret_fast_syscall)
	48
	49	/* Ok, we need to do extra processing, enter the slow path. */
	50	fast_work_pending:
	51	str r0, [sp, #S_R0+S_OFF]! @ returned r0
	52	/* fall through to work_pending */
	53	#else
	54	/*
	55	* The "replacement" ret_fast_syscall for when tracing or context tracking
	56	* is enabled. As we will need to call out to some C functions, we save
	57	* r0 first to avoid needing to save registers around each C function call.
	58	*/
	59	ret_fast_syscall:
	60	UNWIND(.fnstart )
	61	UNWIND(.cantunwind )
	62	str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
	63	disable_irq_notrace @ disable interrupts
	64	ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
	65	tst r1, #_TIF_SYSCALL_WORK \| _TIF_WORK_MASK
	66	beq no_work_pending
	67	UNWIND(.fnend )
	68	ENDPROC(ret_fast_syscall)
	69
	70	/* Slower path - fall through to work_pending */
	71	#endif
	72
	73	tst r1, #_TIF_SYSCALL_WORK
	74	bne __sys_trace_return_nosave
	75	slow_work_pending:
	76	mov r0, sp @ 'regs'
	77	mov r2, why @ 'syscall'
	78	bl do_work_pending
	79	cmp r0, #0
	80	beq no_work_pending
	81	movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
	82	ldmia sp, {r0 - r6} @ have to reload r0 - r6
	83	b local_restart @ ... and off we go
	84	ENDPROC(ret_fast_syscall)
	85
	86	/*
	87	* "slow" syscall return path. "why" tells us if this was a real syscall.
	88	* IRQs may be enabled here, so always disable them. Note that we use the
	89	* "notrace" version to avoid calling into the tracing code unnecessarily.
	90	* do_work_pending() will update this state if necessary.
	91	*/
	92	ENTRY(ret_to_user)
	93	ret_slow_syscall:
	94	disable_irq_notrace @ disable interrupts
	95	ENTRY(ret_to_user_from_irq)
	96	ldr r1, [tsk, #TI_FLAGS]
	97	tst r1, #_TIF_WORK_MASK
	98	bne slow_work_pending
	99	no_work_pending:
	100	asm_trace_hardirqs_on save = 0
	101
	102	/* perform architecture specific actions before user return */
	103	arch_ret_to_user r1, lr
	104	ct_user_enter save = 0
	105
	106	restore_user_regs fast = 0, offset = 0
	107	ENDPROC(ret_to_user_from_irq)
	108	ENDPROC(ret_to_user)
	109
	110	/*
	111	* This is how we return from a fork.
	112	*/
	113	ENTRY(ret_from_fork)
	114	bl schedule_tail
	115	cmp r5, #0
	116	movne r0, r4
	117	badrne lr, 1f
	118	retne r5
	119	1: get_thread_info tsk
	120	b ret_slow_syscall
	121	ENDPROC(ret_from_fork)
	122
	123	.equ NR_syscalls,0
	124	#define CALL(x) .equ NR_syscalls,NR_syscalls+1
	125	#include "calls.S"
	126
	127	/*
	128	* Ensure that the system call table is equal to __NR_syscalls,
	129	* which is the value the rest of the system sees
	130	*/
	131	.ifne NR_syscalls - __NR_syscalls
	132	.error "__NR_syscalls is not equal to the size of the syscall table"
	133	.endif
	134
	135	#undef CALL
	136	#define CALL(x) .long x
	137
	138	/*=============================================================================
	139	* SWI handler
	140	*-----------------------------------------------------------------------------
	141	*/
	142
	143	.align 5
	144	ENTRY(vector_swi)
	145	#ifdef CONFIG_CPU_V7M
	146	v7m_exception_entry
	147	#else
	148	sub sp, sp, #S_FRAME_SIZE
	149	stmia sp, {r0 - r12} @ Calling r0 - r12
	150	ARM( add r8, sp, #S_PC )
	151	ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
	152	THUMB( mov r8, sp )
	153	THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
	154	mrs r8, spsr @ called from non-FIQ mode, so ok.
	155	str lr, [sp, #S_PC] @ Save calling PC
	156	str r8, [sp, #S_PSR] @ Save CPSR
	157	str r0, [sp, #S_OLD_R0] @ Save OLD_R0
	158	#endif
	159	zero_fp
	160	alignment_trap r10, ip, __cr_alignment
	161	enable_irq
	162	ct_user_exit
	163	get_thread_info tsk
	164
	165	/*
	166	* Get the system call number.
	167	*/
	168
	169	#if defined(CONFIG_OABI_COMPAT)
	170
	171	/*
	172	* If we have CONFIG_OABI_COMPAT then we need to look at the swi
	173	* value to determine if it is an EABI or an old ABI call.
	174	*/
	175	#ifdef CONFIG_ARM_THUMB
	176	tst r8, #PSR_T_BIT
	177	movne r10, #0 @ no thumb OABI emulation
	178	USER( ldreq r10, [lr, #-4] ) @ get SWI instruction
	179	#else
	180	USER( ldr r10, [lr, #-4] ) @ get SWI instruction
	181	#endif
	182	ARM_BE8(rev r10, r10) @ little endian instruction
	183
	184	#elif defined(CONFIG_AEABI)
	185
	186	/*
	187	* Pure EABI user space always put syscall number into scno (r7).
	188	*/
	189	#elif defined(CONFIG_ARM_THUMB)
	190	/* Legacy ABI only, possibly thumb mode. */
	191	tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
	192	addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
	193	USER( ldreq scno, [lr, #-4] )
	194
	195	#else
	196	/* Legacy ABI only. */
	197	USER( ldr scno, [lr, #-4] ) @ get SWI instruction
	198	#endif
	199
	200	uaccess_disable tbl
	201
	202	adr tbl, sys_call_table @ load syscall table pointer
	203
	204	#if defined(CONFIG_OABI_COMPAT)
	205	/*
	206	* If the swi argument is zero, this is an EABI call and we do nothing.
	207	*
	208	* If this is an old ABI call, get the syscall number into scno and
	209	* get the old ABI syscall table address.
	210	*/
	211	bics r10, r10, #0xff000000
	212	eorne scno, r10, #__NR_OABI_SYSCALL_BASE
	213	ldrne tbl, =sys_oabi_call_table
	214	#elif !defined(CONFIG_AEABI)
	215	bic scno, scno, #0xff000000 @ mask off SWI op-code
	216	eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
	217	#endif
	218
	219	local_restart:
	220	ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
	221	stmdb sp!, {r4, r5} @ push fifth and sixth args
	222
	223	tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
	224	bne __sys_trace
	225
	226	cmp scno, #NR_syscalls @ check upper syscall limit
	227	badr lr, ret_fast_syscall @ return address
	228	ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
	229
	230	add r1, sp, #S_OFF
	231	2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
	232	eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
	233	bcs arm_syscall
	234	mov why, #0 @ no longer a real syscall
	235	b sys_ni_syscall @ not private func
	236
	237	#if defined(CONFIG_OABI_COMPAT) \|\| !defined(CONFIG_AEABI)
	238	/*
	239	* We failed to handle a fault trying to access the page
	240	* containing the swi instruction, but we're not really in a
	241	* position to return -EFAULT. Instead, return back to the
	242	* instruction and re-enter the user fault handling path trying
	243	* to page it in. This will likely result in sending SEGV to the
	244	* current task.
	245	*/
	246	9001:
	247	sub lr, lr, #4
	248	str lr, [sp, #S_PC]
	249	b ret_fast_syscall
	250	#endif
	251	ENDPROC(vector_swi)
	252
	253	/*
	254	* This is the really slow path. We're going to be doing
	255	* context switches, and waiting for our parent to respond.
	256	*/
	257	__sys_trace:
	258	mov r1, scno
	259	add r0, sp, #S_OFF
	260	bl syscall_trace_enter
	261
	262	badr lr, __sys_trace_return @ return address
	263	mov scno, r0 @ syscall number (possibly new)
	264	add r1, sp, #S_R0 + S_OFF @ pointer to regs
	265	cmp scno, #NR_syscalls @ check upper syscall limit
	266	ldmccia r1, {r0 - r6} @ have to reload r0 - r6
	267	stmccia sp, {r4, r5} @ and update the stack args
	268	ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
	269	cmp scno, #-1 @ skip the syscall?
	270	bne 2b
	271	add sp, sp, #S_OFF @ restore stack
	272	b ret_slow_syscall
	273
	274	__sys_trace_return:
	275	str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
	276	mov r0, sp
	277	bl syscall_trace_exit
	278	b ret_slow_syscall
	279
	280	__sys_trace_return_nosave:
	281	enable_irq_notrace
	282	mov r0, sp
	283	bl syscall_trace_exit
	284	b ret_slow_syscall
	285
	286	.align 5
	287	#ifdef CONFIG_ALIGNMENT_TRAP
	288	.type __cr_alignment, #object
	289	__cr_alignment:
	290	.word cr_alignment
	291	#endif
	292	.ltorg
	293
	294	/*
	295	* This is the syscall table declaration for native ABI syscalls.
	296	* With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
	297	*/
	298	#define ABI(native, compat) native
	299	#ifdef CONFIG_AEABI
	300	#define OBSOLETE(syscall) sys_ni_syscall
	301	#else
	302	#define OBSOLETE(syscall) syscall
	303	#endif
	304
	305	.type sys_call_table, #object
	306	ENTRY(sys_call_table)
	307	#include "calls.S"
	308	#undef ABI
	309	#undef OBSOLETE
	310
	311	/*============================================================================
	312	* Special system call wrappers
	313	*/
	314	@ r0 = syscall number
	315	@ r8 = syscall table
	316	sys_syscall:
	317	bic scno, r0, #__NR_OABI_SYSCALL_BASE
	318	cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
	319	cmpne scno, #NR_syscalls @ check range
	320	stmloia sp, {r5, r6} @ shuffle args
	321	movlo r0, r1
	322	movlo r1, r2
	323	movlo r2, r3
	324	movlo r3, r4
	325	ldrlo pc, [tbl, scno, lsl #2]
	326	b sys_ni_syscall
	327	ENDPROC(sys_syscall)
	328
	329	sys_sigreturn_wrapper:
	330	add r0, sp, #S_OFF
	331	mov why, #0 @ prevent syscall restart handling
	332	b sys_sigreturn
	333	ENDPROC(sys_sigreturn_wrapper)
	334
	335	sys_rt_sigreturn_wrapper:
	336	add r0, sp, #S_OFF
	337	mov why, #0 @ prevent syscall restart handling
	338	b sys_rt_sigreturn
	339	ENDPROC(sys_rt_sigreturn_wrapper)
	340
	341	sys_statfs64_wrapper:
	342	teq r1, #88
	343	moveq r1, #84
	344	b sys_statfs64
	345	ENDPROC(sys_statfs64_wrapper)
	346
	347	sys_fstatfs64_wrapper:
	348	teq r1, #88
	349	moveq r1, #84
	350	b sys_fstatfs64
	351	ENDPROC(sys_fstatfs64_wrapper)
	352
	353	/*
	354	* Note: off_4k (r5) is always units of 4K. If we can't do the requested
	355	* offset, we return EINVAL.
	356	*/
	357	sys_mmap2:
	358	#if PAGE_SHIFT > 12
	359	tst r5, #PGOFF_MASK
	360	moveq r5, r5, lsr #PAGE_SHIFT - 12
	361	streq r5, [sp, #4]
	362	beq sys_mmap_pgoff
	363	mov r0, #-EINVAL
	364	ret lr
	365	#else
	366	str r5, [sp, #4]
	367	b sys_mmap_pgoff
	368	#endif
	369	ENDPROC(sys_mmap2)
	370
	371	#ifdef CONFIG_OABI_COMPAT
	372
	373	/*
	374	* These are syscalls with argument register differences
	375	*/
	376
	377	sys_oabi_pread64:
	378	stmia sp, {r3, r4}
	379	b sys_pread64
	380	ENDPROC(sys_oabi_pread64)
	381
	382	sys_oabi_pwrite64:
	383	stmia sp, {r3, r4}
	384	b sys_pwrite64
	385	ENDPROC(sys_oabi_pwrite64)
	386
	387	sys_oabi_truncate64:
	388	mov r3, r2
	389	mov r2, r1
	390	b sys_truncate64
	391	ENDPROC(sys_oabi_truncate64)
	392
	393	sys_oabi_ftruncate64:
	394	mov r3, r2
	395	mov r2, r1
	396	b sys_ftruncate64
	397	ENDPROC(sys_oabi_ftruncate64)
	398
	399	sys_oabi_readahead:
	400	str r3, [sp]
	401	mov r3, r2
	402	mov r2, r1
	403	b sys_readahead
	404	ENDPROC(sys_oabi_readahead)
	405
	406	/*
	407	* Let's declare a second syscall table for old ABI binaries
	408	* using the compatibility syscall entries.
	409	*/
	410	#define ABI(native, compat) compat
	411	#define OBSOLETE(syscall) syscall
	412
	413	.type sys_oabi_call_table, #object
	414	ENTRY(sys_oabi_call_table)
	415	#include "calls.S"
	416	#undef ABI
	417	#undef OBSOLETE
	418
	419	#endif
	420