arch/sparc/kernel/switch.S

/* */
   1 /* $Id: switch.S,v 1.18 1996/04/03 02:15:00 davem Exp $
   2  * switch.S: Sparc task switch code.
   3  *
   4  * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
   5  */
   6 
   7 #include <asm/head.h>
   8 #include <asm/asi.h>
   9 #include <asm/contregs.h>
  10 #include <asm/cprefix.h>
  11 #include <asm/psr.h>
  12 #include <asm/asmmacro.h>
  13 #include <asm/ptrace.h>
  14 #include <asm/winmacro.h>
  15 
  16 #define sw_ntask     g1
  17 #define sw_psr       g4
  18 #define sw_wim       g5
  19 #define sw_tmp       g6
  20 #define sw_ctx       g7
  21 
  22 /* Context switch code.  The new process's task_struct
  23  * ptr is passed as the first parameter.
  24  *
  25  * First successful task switch 05/13/95 21:52:37
  26  */
  27         .align 4
  28         .globl  C_LABEL(sparc_switch_to)
  29 C_LABEL(sparc_switch_to):
  30         mov     %o0, %sw_ntask
  31 
  32         /* Save kernel state. */
  33         FLUSH_ALL_KERNEL_WINDOWS; 
  34         STORE_WINDOW(sp)
  35         rd      %psr, %sw_psr
  36         LOAD_CURRENT(sw_tmp, sw_wim)
  37         rd      %wim, %sw_wim
  38         std     %sw_psr, [%sw_tmp + THREAD_KPSR]
  39         std     %sp, [%sw_tmp + THREAD_KSP]
  40 
  41         /* Load new kernel state. */
  42         wr      %sw_psr, PSR_ET, %psr
  43         WRITE_PAUSE
  44 #ifdef __SMP__
  45         GET_PROCESSOR_OFFSET(sw_psr)
  46         set     C_LABEL(current_set), %sw_tmp
  47         st      %sw_ntask, [%sw_tmp + %sw_psr]
  48 #else
  49         sethi   %hi(C_LABEL(current_set)), %sw_tmp
  50         st      %sw_ntask, [%sw_tmp + %lo(C_LABEL(current_set))]
  51 #endif
  52         ldd     [%sw_ntask + THREAD_KPSR], %sw_psr
  53         wr      %sw_psr, PSR_ET, %psr
  54         WRITE_PAUSE
  55         wr      %sw_wim, 0x0, %wim
  56         WRITE_PAUSE
  57         ldd     [%sw_ntask + THREAD_KSP], %sp
  58         LOAD_WINDOW(sp)
  59 
  60         wr      %sw_psr, 0x0, %psr              ! traps back on
  61         WRITE_PAUSE
  62 
  63         retl
  64          nop
  65 
  66 
  67 #ifdef __SMP__
  68         /* Because of nasty register windows this is the only way
  69          * to start a processor into it's cpu_idle() thread.
  70          */
  71 
  72         .globl  C_LABEL(sparc_cpusched)
  73 C_LABEL(sparc_cpusched):
  74         LOAD_CURRENT(g1, g2)
  75         rd      %psr, %g7
  76 
  77         wr      %g7, PSR_ET, %psr
  78         WRITE_PAUSE
  79 
  80         ldd     [%g1 + THREAD_KPSR], %g2
  81 
  82         wr      %g2, PSR_ET, %psr
  83         WRITE_PAUSE
  84 
  85         wr      %g3, 0x0, %wim
  86         WRITE_PAUSE
  87 
  88         ldd     [%g1 + THREAD_KSP], %sp
  89         LOAD_WINDOW(sp)
  90 
  91         wr      %g2, 0x0, %psr
  92         WRITE_PAUSE
  93 
  94         retl
  95          nop
  96 #endif
/* */
root/arch/sparc/kernel/switch.S
