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/*
 *  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 <linux/config.h>
#include "entry-header.S"

/* 
 * We rely on the fact that R0 is at the bottom of the stack (due to
 * slow/fast restore user regs).
 */
#if S_R0 != 0
#error "Please fix"
#endif

/*
 * Our do_softirq out of line code.  See include/asm-arm/softirq.h for
 * the calling assembly.
 */
ENTRY(__do_softirq)
        stmfd   sp!, {r0 - r3, ip, lr}
        bl      do_softirq
        ldmfd   sp!, {r0 - r3, ip, pc}

        .align  5
/*
 * This is the fast syscall return path.  We do as little as
 * possible here, and this includes saving r0 back into the SVC
 * stack.
 */
ret_fast_syscall:
        disable_irq r1                          @ ensure IRQs are disabled
        ldr     r1, [tsk, #TSK_NEED_RESCHED]
        ldr     r2, [tsk, #TSK_SIGPENDING]
        teq     r1, #0                          @ need_resched || sigpending
        teqeq   r2, #0
        bne     slow
        fast_restore_user_regs

/*
 * Ok, we need to do extra processing, enter the slow path.
 */
slow:   str     r0, [sp, #S_R0+S_OFF]!  @ returned r0
        teq     r1, #0
        beq     1f

/*
 * "slow" syscall return path.  "why" tells us if this was a real syscall.
 */
reschedule:
        bl      SYMBOL_NAME(schedule)
ret_disable_irq:
        disable_irq r1                          @ ensure IRQs are disabled
ENTRY(ret_to_user)
ret_slow_syscall:
        ldr     r1, [tsk, #TSK_NEED_RESCHED]
        ldr     r2, [tsk, #TSK_SIGPENDING]
        teq     r1, #0                          @ need_resched => schedule()
        bne     reschedule
1:      teq     r2, #0                          @ sigpending => do_signal()
        bne     __do_signal
restore:
        restore_user_regs

__do_signal:
        enable_irq r1
        mov     r0, #0                          @ NULL 'oldset'
        mov     r1, sp                          @ 'regs'
        mov     r2, why                         @ 'syscall'
        bl      SYMBOL_NAME(do_signal)          @ note the bl above sets lr
        disable_irq r1                          @ ensure IRQs are disabled
        b       restore

/*
 * This is how we return from a fork.  __switch_to will be calling us
 * with r0 pointing at the previous task that was running (ready for
 * calling schedule_tail).
 */
ENTRY(ret_from_fork)
        bl      SYMBOL_NAME(schedule_tail)
        get_current_task tsk
        ldr     ip, [tsk, #TSK_PTRACE]          @ check for syscall tracing
        mov     why, #1
        tst     ip, #PT_TRACESYS                @ are we tracing syscalls?
        beq     ret_disable_irq
        mov     r1, sp
        mov     r0, #1                          @ trace exit [IP = 1]
        bl      SYMBOL_NAME(syscall_trace)
        b       ret_disable_irq
        

#include "calls.S"

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

        /* If we're optimising for StrongARM the resulting code won't 
           run on an ARM7 and we can save a couple of instructions.  
                                                                --pb */
#ifdef CONFIG_CPU_ARM710
        .macro  arm710_bug_check, instr, temp
        and     \temp, \instr, #0x0f000000      @ check for SWI
        teq     \temp, #0x0f000000
        bne     .Larm700bug
        .endm

.Larm700bug:
        ldr     r0, [sp, #S_PSR]                @ Get calling cpsr
        sub     lr, lr, #4
        str     lr, [r8]
        msr     spsr, r0
        ldmia   sp, {r0 - lr}^                  @ Get calling r0 - lr
        mov     r0, r0
        ldr     lr, [sp, #S_PC]                 @ Get PC
        add     sp, sp, #S_FRAME_SIZE
        movs    pc, lr
#else
        .macro  arm710_bug_check, instr, temp
        .endm
#endif

        .align  5
ENTRY(vector_swi)
        save_user_regs
        zero_fp
        get_scno
        arm710_bug_check scno, ip

#ifdef CONFIG_ALIGNMENT_TRAP
        ldr     ip, __cr_alignment
        ldr     ip, [ip]
        mcr     p15, 0, ip, c1, c0              @ update control register
#endif
        enable_irq ip

        str     r4, [sp, #-S_OFF]!              @ push fifth arg

        get_current_task tsk
        ldr     ip, [tsk, #TSK_PTRACE]          @ check for syscall tracing
        bic     scno, scno, #0xff000000         @ mask off SWI op-code
        eor     scno, scno, #OS_NUMBER << 20    @ check OS number
        adr     tbl, sys_call_table             @ load syscall table pointer
        tst     ip, #PT_TRACESYS                @ are we tracing syscalls?
        bne     __sys_trace

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

        add     r1, sp, #S_OFF
2:      mov     why, #0                         @ no longer a real syscall
        cmp     scno, #ARMSWI_OFFSET
        eor     r0, scno, #OS_NUMBER << 20      @ put OS number back
        bcs     SYMBOL_NAME(arm_syscall)        
        b       SYMBOL_NAME(sys_ni_syscall)     @ not private func

        /*
         * This is the really slow path.  We're going to be doing
         * context switches, and waiting for our parent to respond.
         */
__sys_trace:
        add     r1, sp, #S_OFF
        mov     r0, #0                          @ trace entry [IP = 0]
        bl      SYMBOL_NAME(syscall_trace)

        adrsvc  al, lr, __sys_trace_return      @ return address
        add     r1, sp, #S_R0 + S_OFF           @ pointer to regs
        cmp     scno, #NR_syscalls              @ check upper syscall limit
        ldmccia r1, {r0 - r3}                   @ have to reload r0 - r3
        ldrcc   pc, [tbl, scno, lsl #2]         @ call sys_* routine
        b       2b

__sys_trace_return:
        str     r0, [sp, #S_R0 + S_OFF]!        @ save returned r0
        mov     r1, sp
        mov     r0, #1                          @ trace exit [IP = 1]
        bl      SYMBOL_NAME(syscall_trace)
        b       ret_disable_irq

        .align  5
#ifdef CONFIG_ALIGNMENT_TRAP
        .type   __cr_alignment, #object
__cr_alignment:
        .word   SYMBOL_NAME(cr_alignment)
#endif

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

/*============================================================================
 * Special system call wrappers
 */
@ r0 = syscall number
@ r5 = syscall table
                .type   sys_syscall, #function
SYMBOL_NAME(sys_syscall):
                eor     scno, r0, #OS_NUMBER << 20
                cmp     scno, #NR_syscalls      @ check range
                stmleia sp, {r5, r6}            @ shuffle args
                movle   r0, r1
                movle   r1, r2
                movle   r2, r3
                movle   r3, r4
                ldrle   pc, [tbl, scno, lsl #2]
                b       sys_ni_syscall

sys_fork_wrapper:
                add     r0, sp, #S_OFF
                b       SYMBOL_NAME(sys_fork)

sys_vfork_wrapper:
                add     r0, sp, #S_OFF
                b       SYMBOL_NAME(sys_vfork)

sys_execve_wrapper:
                add     r3, sp, #S_OFF
                b       SYMBOL_NAME(sys_execve)

sys_clone_wapper:
                add     r2, sp, #S_OFF
                b       SYMBOL_NAME(sys_clone)

sys_sigsuspend_wrapper:
                add     r3, sp, #S_OFF
                b       SYMBOL_NAME(sys_sigsuspend)

sys_rt_sigsuspend_wrapper:
                add     r2, sp, #S_OFF
                b       SYMBOL_NAME(sys_rt_sigsuspend)

sys_sigreturn_wrapper:
                add     r0, sp, #S_OFF
                b       SYMBOL_NAME(sys_sigreturn)

sys_rt_sigreturn_wrapper:
                add     r0, sp, #S_OFF
                b       SYMBOL_NAME(sys_rt_sigreturn)

sys_sigaltstack_wrapper:
                ldr     r2, [sp, #S_OFF + S_SP]
                b       do_sigaltstack

/*
 * 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     do_mmap2
                mov     r0, #-EINVAL
                RETINSTR(mov,pc, lr)
#else
                str     r5, [sp, #4]
                b       do_mmap2
#endif