400 lines
9.1 KiB
ArmAsm
400 lines
9.1 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/arch/entry-macro.S>
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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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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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@ fast_restore_user_regs
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ldr r1, [sp, #S_OFF + S_PSR] @ get calling cpsr
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ldr lr, [sp, #S_OFF + S_PC]! @ get pc
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msr spsr_cxsf, r1 @ save in spsr_svc
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ldmdb sp, {r1 - lr}^ @ get calling r1 - lr
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mov r0, r0
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add sp, sp, #S_FRAME_SIZE - S_PC
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movs pc, lr @ return & move spsr_svc into cpsr
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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
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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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@ slow_restore_user_regs
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ldr r1, [sp, #S_PSR] @ get calling cpsr
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ldr lr, [sp, #S_PC]! @ get pc
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msr spsr_cxsf, r1 @ save in spsr_svc
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ldmdb sp, {r0 - lr}^ @ get calling r0 - lr
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mov r0, r0
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add sp, sp, #S_FRAME_SIZE - S_PC
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movs pc, lr @ return & move spsr_svc into cpsr
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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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.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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/*=============================================================================
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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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add r8, sp, #S_PC
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stmdb r8, {sp, lr}^ @ 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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#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, 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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/*
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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, __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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.type sys_syscall, #function
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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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sys_fork_wrapper:
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add r0, sp, #S_OFF
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b sys_fork
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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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sys_execve_wrapper:
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add r3, sp, #S_OFF
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b sys_execve
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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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sys_sigsuspend_wrapper:
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add r3, sp, #S_OFF
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b sys_sigsuspend
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sys_rt_sigsuspend_wrapper:
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add r2, sp, #S_OFF
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b sys_rt_sigsuspend
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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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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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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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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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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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/*
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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 do_mmap2
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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 do_mmap2
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#endif
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#ifdef CONFIG_OABI_COMPAT
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/*
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* These are syscalls with argument register differences
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*/
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sys_oabi_pread64:
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stmia sp, {r3, r4}
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b sys_pread64
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sys_oabi_pwrite64:
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stmia sp, {r3, r4}
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b sys_pwrite64
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sys_oabi_truncate64:
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mov r3, r2
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mov r2, r1
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b sys_truncate64
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sys_oabi_ftruncate64:
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mov r3, r2
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mov r2, r1
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b sys_ftruncate64
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sys_oabi_readahead:
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str r3, [sp]
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mov r3, r2
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mov r2, r1
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b sys_readahead
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/*
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* Let's declare a second syscall table for old ABI binaries
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* using the compatibility syscall entries.
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*/
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#define ABI(native, compat) compat
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#define OBSOLETE(syscall) syscall
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.type sys_oabi_call_table, #object
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ENTRY(sys_oabi_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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#endif
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