478 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			478 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
/*
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 *  linux/arch/arm/kernel/entry-common.S
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 *
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 *  Copyright (C) 2000 Russell King
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License version 2 as
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 * published by the Free Software Foundation.
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 */
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#include <asm/unistd.h>
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#include <asm/ftrace.h>
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#include <mach/entry-macro.S>
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#include <asm/unwind.h>
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#include "entry-header.S"
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	.align	5
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/*
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 * This is the fast syscall return path.  We do as little as
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 * possible here, and this includes saving r0 back into the SVC
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 * stack.
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 */
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ret_fast_syscall:
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 UNWIND(.fnstart	)
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 UNWIND(.cantunwind	)
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	disable_irq				@ disable interrupts
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	ldr	r1, [tsk, #TI_FLAGS]
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	tst	r1, #_TIF_WORK_MASK
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	bne	fast_work_pending
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	/* perform architecture specific actions before user return */
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	arch_ret_to_user r1, lr
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	restore_user_regs fast = 1, offset = S_OFF
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 UNWIND(.fnend		)
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/*
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 * Ok, we need to do extra processing, enter the slow path.
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 */
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fast_work_pending:
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	str	r0, [sp, #S_R0+S_OFF]!		@ returned r0
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work_pending:
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	tst	r1, #_TIF_NEED_RESCHED
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	bne	work_resched
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	tst	r1, #_TIF_SIGPENDING|_TIF_NOTIFY_RESUME
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	beq	no_work_pending
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	mov	r0, sp				@ 'regs'
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	mov	r2, why				@ 'syscall'
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	bl	do_notify_resume
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	b	ret_slow_syscall		@ Check work again
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work_resched:
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	bl	schedule
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/*
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 * "slow" syscall return path.  "why" tells us if this was a real syscall.
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 */
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ENTRY(ret_to_user)
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ret_slow_syscall:
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	disable_irq				@ disable interrupts
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	ldr	r1, [tsk, #TI_FLAGS]
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	tst	r1, #_TIF_WORK_MASK
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	bne	work_pending
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no_work_pending:
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	/* perform architecture specific actions before user return */
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	arch_ret_to_user r1, lr
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	restore_user_regs fast = 0, offset = 0
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ENDPROC(ret_to_user)
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/*
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 * This is how we return from a fork.
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 */
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ENTRY(ret_from_fork)
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	bl	schedule_tail
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	get_thread_info tsk
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	ldr	r1, [tsk, #TI_FLAGS]		@ check for syscall tracing
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	mov	why, #1
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	tst	r1, #_TIF_SYSCALL_TRACE		@ are we tracing syscalls?
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	beq	ret_slow_syscall
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	mov	r1, sp
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	mov	r0, #1				@ trace exit [IP = 1]
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	bl	syscall_trace
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	b	ret_slow_syscall
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ENDPROC(ret_from_fork)
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	.equ NR_syscalls,0
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#define CALL(x) .equ NR_syscalls,NR_syscalls+1
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#include "calls.S"
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#undef CALL
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#define CALL(x) .long x
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#ifdef CONFIG_FUNCTION_TRACER
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#ifdef CONFIG_DYNAMIC_FTRACE
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ENTRY(mcount)
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	stmdb sp!, {r0-r3, lr}
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	mov r0, lr
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	sub r0, r0, #MCOUNT_INSN_SIZE
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	.globl mcount_call
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mcount_call:
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	bl ftrace_stub
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	ldr lr, [fp, #-4]			@ restore lr
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	ldmia sp!, {r0-r3, pc}
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ENTRY(ftrace_caller)
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	stmdb sp!, {r0-r3, lr}
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	ldr r1, [fp, #-4]
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	mov r0, lr
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	sub r0, r0, #MCOUNT_INSN_SIZE
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	.globl ftrace_call
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ftrace_call:
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	bl ftrace_stub
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	ldr lr, [fp, #-4]			@ restore lr
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	ldmia sp!, {r0-r3, pc}
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#else
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ENTRY(__gnu_mcount_nc)
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	stmdb sp!, {r0-r3, lr}
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	ldr r0, =ftrace_trace_function
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	ldr r2, [r0]
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	adr r0, ftrace_stub
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	cmp r0, r2
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	bne gnu_trace
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	ldmia sp!, {r0-r3, ip, lr}
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	mov pc, ip
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gnu_trace:
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	ldr r1, [sp, #20]			@ lr of instrumented routine
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	mov r0, lr
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	sub r0, r0, #MCOUNT_INSN_SIZE
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	mov lr, pc
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	mov pc, r2
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	ldmia sp!, {r0-r3, ip, lr}
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	mov pc, ip
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ENTRY(mcount)
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	stmdb sp!, {r0-r3, lr}
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	ldr r0, =ftrace_trace_function
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	ldr r2, [r0]
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	adr r0, ftrace_stub
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	cmp r0, r2
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	bne trace
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	ldr lr, [fp, #-4]			@ restore lr
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	ldmia sp!, {r0-r3, pc}
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trace:
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	ldr r1, [fp, #-4]			@ lr of instrumented routine
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	mov r0, lr
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	sub r0, r0, #MCOUNT_INSN_SIZE
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	mov lr, pc
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	mov pc, r2
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	ldr lr, [fp, #-4]			@ restore lr
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	ldmia sp!, {r0-r3, pc}
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#endif /* CONFIG_DYNAMIC_FTRACE */
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	.globl ftrace_stub
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ftrace_stub:
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	mov pc, lr
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#endif /* CONFIG_FUNCTION_TRACER */
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/*=============================================================================
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 * SWI handler
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 *-----------------------------------------------------------------------------
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 */
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	/* If we're optimising for StrongARM the resulting code won't 
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	   run on an ARM7 and we can save a couple of instructions.  
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								--pb */
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#ifdef CONFIG_CPU_ARM710
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#define A710(code...) code
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.Larm710bug:
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	ldmia	sp, {r0 - lr}^			@ Get calling r0 - lr
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	mov	r0, r0
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	add	sp, sp, #S_FRAME_SIZE
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	subs	pc, lr, #4
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#else
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#define A710(code...)
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#endif
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	.align	5
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ENTRY(vector_swi)
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	sub	sp, sp, #S_FRAME_SIZE
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	stmia	sp, {r0 - r12}			@ Calling r0 - r12
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 ARM(	add	r8, sp, #S_PC		)
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 ARM(	stmdb	r8, {sp, lr}^		)	@ Calling sp, lr
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 THUMB(	mov	r8, sp			)
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 THUMB(	store_user_sp_lr r8, r10, S_SP	)	@ calling sp, lr
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	mrs	r8, spsr			@ called from non-FIQ mode, so ok.
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	str	lr, [sp, #S_PC]			@ Save calling PC
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	str	r8, [sp, #S_PSR]		@ Save CPSR
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	str	r0, [sp, #S_OLD_R0]		@ Save OLD_R0
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	zero_fp
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	/*
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	 * Get the system call number.
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	 */
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#if defined(CONFIG_OABI_COMPAT)
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	/*
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	 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
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	 * value to determine if it is an EABI or an old ABI call.
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	 */
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#ifdef CONFIG_ARM_THUMB
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	tst	r8, #PSR_T_BIT
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	movne	r10, #0				@ no thumb OABI emulation
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	ldreq	r10, [lr, #-4]			@ get SWI instruction
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#else
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	ldr	r10, [lr, #-4]			@ get SWI instruction
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  A710(	and	ip, r10, #0x0f000000		@ check for SWI		)
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  A710(	teq	ip, #0x0f000000						)
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  A710(	bne	.Larm710bug						)
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#endif
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#ifdef CONFIG_CPU_ENDIAN_BE8
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	rev	r10, r10			@ little endian instruction
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#endif
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#elif defined(CONFIG_AEABI)
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	/*
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	 * Pure EABI user space always put syscall number into scno (r7).
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	 */
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  A710(	ldr	ip, [lr, #-4]			@ get SWI instruction	)
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  A710(	and	ip, ip, #0x0f000000		@ check for SWI		)
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  A710(	teq	ip, #0x0f000000						)
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  A710(	bne	.Larm710bug						)
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#elif defined(CONFIG_ARM_THUMB)
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	/* Legacy ABI only, possibly thumb mode. */
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	tst	r8, #PSR_T_BIT			@ this is SPSR from save_user_regs
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	addne	scno, r7, #__NR_SYSCALL_BASE	@ put OS number in
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	ldreq	scno, [lr, #-4]
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#else
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	/* Legacy ABI only. */
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	ldr	scno, [lr, #-4]			@ get SWI instruction
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  A710(	and	ip, scno, #0x0f000000		@ check for SWI		)
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  A710(	teq	ip, #0x0f000000						)
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  A710(	bne	.Larm710bug						)
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#endif
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#ifdef CONFIG_ALIGNMENT_TRAP
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	ldr	ip, __cr_alignment
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	ldr	ip, [ip]
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	mcr	p15, 0, ip, c1, c0		@ update control register
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#endif
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	enable_irq
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	get_thread_info tsk
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	adr	tbl, sys_call_table		@ load syscall table pointer
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	ldr	ip, [tsk, #TI_FLAGS]		@ check for syscall tracing
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#if defined(CONFIG_OABI_COMPAT)
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	/*
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	 * If the swi argument is zero, this is an EABI call and we do nothing.
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	 *
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	 * If this is an old ABI call, get the syscall number into scno and
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	 * get the old ABI syscall table address.
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	 */
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	bics	r10, r10, #0xff000000
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	eorne	scno, r10, #__NR_OABI_SYSCALL_BASE
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	ldrne	tbl, =sys_oabi_call_table
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#elif !defined(CONFIG_AEABI)
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	bic	scno, scno, #0xff000000		@ mask off SWI op-code
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	eor	scno, scno, #__NR_SYSCALL_BASE	@ check OS number
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#endif
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	stmdb	sp!, {r4, r5}			@ push fifth and sixth args
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	tst	ip, #_TIF_SYSCALL_TRACE		@ are we tracing syscalls?
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	bne	__sys_trace
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	cmp	scno, #NR_syscalls		@ check upper syscall limit
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	adr	lr, BSYM(ret_fast_syscall)	@ return address
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	ldrcc	pc, [tbl, scno, lsl #2]		@ call sys_* routine
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	add	r1, sp, #S_OFF
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2:	mov	why, #0				@ no longer a real syscall
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	cmp	scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
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	eor	r0, scno, #__NR_SYSCALL_BASE	@ put OS number back
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	bcs	arm_syscall	
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	b	sys_ni_syscall			@ not private func
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ENDPROC(vector_swi)
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	/*
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	 * This is the really slow path.  We're going to be doing
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	 * context switches, and waiting for our parent to respond.
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	 */
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__sys_trace:
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	mov	r2, scno
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	add	r1, sp, #S_OFF
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	mov	r0, #0				@ trace entry [IP = 0]
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	bl	syscall_trace
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	adr	lr, BSYM(__sys_trace_return)	@ return address
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	mov	scno, r0			@ syscall number (possibly new)
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	add	r1, sp, #S_R0 + S_OFF		@ pointer to regs
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	cmp	scno, #NR_syscalls		@ check upper syscall limit
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	ldmccia	r1, {r0 - r3}			@ have to reload r0 - r3
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	ldrcc	pc, [tbl, scno, lsl #2]		@ call sys_* routine
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	b	2b
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__sys_trace_return:
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	str	r0, [sp, #S_R0 + S_OFF]!	@ save returned r0
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	mov	r2, scno
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	mov	r1, sp
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	mov	r0, #1				@ trace exit [IP = 1]
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	bl	syscall_trace
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	b	ret_slow_syscall
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	.align	5
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#ifdef CONFIG_ALIGNMENT_TRAP
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	.type	__cr_alignment, #object
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__cr_alignment:
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	.word	cr_alignment
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#endif
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	.ltorg
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/*
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 * This is the syscall table declaration for native ABI syscalls.
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 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
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 */
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#define ABI(native, compat) native
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#ifdef CONFIG_AEABI
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#define OBSOLETE(syscall) sys_ni_syscall
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#else
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#define OBSOLETE(syscall) syscall
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#endif
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	.type	sys_call_table, #object
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ENTRY(sys_call_table)
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#include "calls.S"
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#undef ABI
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#undef OBSOLETE
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/*============================================================================
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 * Special system call wrappers
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 */
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@ r0 = syscall number
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@ r8 = syscall table
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sys_syscall:
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		bic	scno, r0, #__NR_OABI_SYSCALL_BASE
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		cmp	scno, #__NR_syscall - __NR_SYSCALL_BASE
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		cmpne	scno, #NR_syscalls	@ check range
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		stmloia	sp, {r5, r6}		@ shuffle args
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		movlo	r0, r1
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		movlo	r1, r2
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		movlo	r2, r3
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		movlo	r3, r4
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		ldrlo	pc, [tbl, scno, lsl #2]
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		b	sys_ni_syscall
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ENDPROC(sys_syscall)
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sys_fork_wrapper:
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		add	r0, sp, #S_OFF
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		b	sys_fork
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ENDPROC(sys_fork_wrapper)
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sys_vfork_wrapper:
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		add	r0, sp, #S_OFF
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		b	sys_vfork
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ENDPROC(sys_vfork_wrapper)
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sys_execve_wrapper:
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		add	r3, sp, #S_OFF
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		b	sys_execve
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ENDPROC(sys_execve_wrapper)
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sys_clone_wrapper:
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		add	ip, sp, #S_OFF
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		str	ip, [sp, #4]
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		b	sys_clone
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ENDPROC(sys_clone_wrapper)
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sys_sigreturn_wrapper:
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		add	r0, sp, #S_OFF
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		b	sys_sigreturn
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ENDPROC(sys_sigreturn_wrapper)
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sys_rt_sigreturn_wrapper:
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		add	r0, sp, #S_OFF
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		b	sys_rt_sigreturn
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ENDPROC(sys_rt_sigreturn_wrapper)
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sys_sigaltstack_wrapper:
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		ldr	r2, [sp, #S_OFF + S_SP]
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		b	do_sigaltstack
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ENDPROC(sys_sigaltstack_wrapper)
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sys_statfs64_wrapper:
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		teq	r1, #88
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		moveq	r1, #84
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		b	sys_statfs64
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ENDPROC(sys_statfs64_wrapper)
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sys_fstatfs64_wrapper:
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		teq	r1, #88
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		moveq	r1, #84
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		b	sys_fstatfs64
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ENDPROC(sys_fstatfs64_wrapper)
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/*
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 * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
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 * offset, we return EINVAL.
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 */
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sys_mmap2:
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#if PAGE_SHIFT > 12
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		tst	r5, #PGOFF_MASK
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		moveq	r5, r5, lsr #PAGE_SHIFT - 12
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		streq	r5, [sp, #4]
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		beq	sys_mmap_pgoff
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		mov	r0, #-EINVAL
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		mov	pc, lr
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#else
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		str	r5, [sp, #4]
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						|
		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
 | 
						|
 |