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/* $Id: switch.S,v 1.1 2005-12-20 09:50:43 jcastillo Exp $
 * switch.S: Sparc task switch code.
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 */

#include <asm/head.h>
#include <asm/asi.h>
#include <asm/contregs.h>
#include <asm/cprefix.h>
#include <asm/psr.h>
#include <asm/asmmacro.h>
#include <asm/ptrace.h>
#include <asm/winmacro.h>

#define sw_ntask     g1
#define sw_psr       g4
#define sw_wim       g5
#define sw_tmp       g6
#define sw_ctx       g7

/* Context switch code.  The new process's task_struct
 * ptr is passed as the first parameter.
 *
 * First successful task switch 05/13/95 21:52:37
 */
        .align 4
        .globl  C_LABEL(sparc_switch_to)
C_LABEL(sparc_switch_to):
        mov     %o0, %sw_ntask

        /* Save kernel state. */
        FLUSH_ALL_KERNEL_WINDOWS; 
        STORE_WINDOW(sp)
        rd      %psr, %sw_psr
        LOAD_CURRENT(sw_tmp, sw_wim)
        rd      %wim, %sw_wim
        std     %sw_psr, [%sw_tmp + THREAD_KPSR]
        std     %sp, [%sw_tmp + THREAD_KSP]

        /* Load new kernel state. */
        wr      %sw_psr, PSR_ET, %psr
        WRITE_PAUSE
#ifdef __SMP__
        GET_PROCESSOR_OFFSET(sw_psr)
        set     C_LABEL(current_set), %sw_tmp
        st      %sw_ntask, [%sw_tmp + %sw_psr]
#else
        sethi   %hi(C_LABEL(current_set)), %sw_tmp
        st      %sw_ntask, [%sw_tmp + %lo(C_LABEL(current_set))]
#endif
        ldd     [%sw_ntask + THREAD_KPSR], %sw_psr
        wr      %sw_psr, PSR_ET, %psr
        WRITE_PAUSE
        wr      %sw_wim, 0x0, %wim
        WRITE_PAUSE
        ldd     [%sw_ntask + THREAD_KSP], %sp
        LOAD_WINDOW(sp)

        wr      %sw_psr, 0x0, %psr              ! traps back on
        WRITE_PAUSE

        retl
         nop


#ifdef __SMP__
        /* Because of nasty register windows this is the only way
         * to start a processor into its cpu_idle() thread.
         */

        .globl  C_LABEL(sparc_cpusched)
C_LABEL(sparc_cpusched):
        LOAD_CURRENT(g1, g2)
        rd      %psr, %g7

        wr      %g7, PSR_ET, %psr
        WRITE_PAUSE

        ldd     [%g1 + THREAD_KPSR], %g2

        wr      %g2, PSR_ET, %psr
        WRITE_PAUSE

        wr      %g3, 0x0, %wim
        WRITE_PAUSE

        ldd     [%g1 + THREAD_KSP], %sp
        LOAD_WINDOW(sp)

        wr      %g2, 0x0, %psr
        WRITE_PAUSE

        retl
         nop
#endif