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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Low level exception handling
 *
 * Copyright (C) 1994 - 2000, 2001 Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics
 * Copyright (C) 2001 MIPS Technologies, Inc.
 */
#include <asm/asm.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#include <asm/offset.h>
#include <asm/stackframe.h>

#define KU_USER 0x10

                .text
                .align  5
FEXPORT(ret_from_fork)
                move    a0, v0                  # prev
                jal     schedule_tail
                ld      t0, TASK_PTRACE($28)    # syscall tracing enabled?
                andi    t0, _PT_TRACESYS
                bnez    t0, tracesys_exit
                j       ret_from_sys_call

tracesys_exit:
                jal     syscall_trace
                b       ret_from_sys_call

EXPORT(ret_from_irq)
EXPORT(ret_from_exception)
                ld      t0, PT_STATUS(sp)       # returning to kernel mode?
                andi    t0, t0, KU_USER
                bnez    t0, ret_from_sys_call
                j       restore_all

reschedule:     jal     schedule

FEXPORT(ret_from_sys_call)
                mfc0    t0, CP0_STATUS  # need_resched and signals atomic test
                ori     t0, t0, 1
                xori    t0, t0, 1
                mtc0    t0, CP0_STATUS
                SSNOP; SSNOP; SSNOP

                ld      v0, TASK_NEED_RESCHED($28)
                lw      v1, TASK_SIGPENDING($28)
                bnez    v0, reschedule
                bnez    v1, signal_return

restore_all:    .set    noat
                RESTORE_ALL
                eret
                .set    at

signal_return:  .type   signal_return, @function

                mfc0    t0, CP0_STATUS
                ori     t0, t0, 1
                mtc0    t0, CP0_STATUS

                move    a0, zero
                move    a1, sp
                jal     do_signal
                b       restore_all

/*
 * Common spurious interrupt handler.
 */
                .text
                .align  5
LEAF(spurious_interrupt)
                /*
                 * Someone tried to fool us by sending an interrupt but we
                 * couldn't find a cause for it.
                 */
                lui     t1, %hi(irq_err_count)
1:              ll      t0, %lo(irq_err_count)(t1)
                addiu   t0, 1
                sc      t0, %lo(irq_err_count)(t1)
                beqz    t0, 1b
                j       ret_from_irq
                END(spurious_interrupt)