arch/mn10300/kernel/switch_to.S

   1 ###############################################################################
   2 #
   3 # MN10300 Context switch operation
   4 #
   5 # Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   6 # Written by David Howells (dhowells@redhat.com)
   7 #
   8 # This program is free software; you can redistribute it and/or
   9 # modify it under the terms of the GNU General Public Licence
  10 # as published by the Free Software Foundation; either version
  11 # 2 of the Licence, or (at your option) any later version.
  12 #
  13 ###############################################################################
  14 #include <linux/sys.h>
  15 #include <linux/linkage.h>
  16 #include <asm/thread_info.h>
  17 #include <asm/cpu-regs.h>
  18
  19         .text
  20
  21 ###############################################################################
  22 #
  23 # struct task_struct *__switch_to(struct thread_struct *prev,
  24 #                                 struct thread_struct *next,
  25 #                                 struct task_struct *prev_task)
  26 #
  27 ###############################################################################
  28 ENTRY(__switch_to)
  29         movm    [d2,d3,a2,a3,exreg1],(sp)
  30         or      EPSW_NMID,epsw
  31
  32         mov     (44,sp),d2
  33
  34         mov     d0,a0
  35         mov     d1,a1
  36
  37         # save prev context
  38         mov     (__frame),d0
  39         mov     d0,(THREAD_FRAME,a0)
  40         mov     __switch_back,d0
  41         mov     d0,(THREAD_PC,a0)
  42         mov     sp,a2
  43         mov     a2,(THREAD_SP,a0)
  44         mov     a3,(THREAD_A3,a0)
  45
  46         mov     (THREAD_A3,a1),a3
  47         mov     (THREAD_SP,a1),a2
  48
  49         # switch
  50         mov     a2,sp
  51
  52         # load next context
  53         GET_THREAD_INFO a2
  54         mov     a2,(__current_ti)
  55         mov     (TI_task,a2),a2
  56         mov     a2,(__current)
  57 #ifdef CONFIG_MN10300_CURRENT_IN_E2
  58         mov     a2,e2
  59 #endif
  60
  61         mov     (THREAD_FRAME,a1),a2
  62         mov     a2,(__frame)
  63         mov     (THREAD_PC,a1),a2
  64         mov     d2,d0                   # for ret_from_fork
  65         mov     d0,a0                   # for __switch_to
  66
  67         jmp     (a2)
  68
  69 __switch_back:
  70         and     ~EPSW_NMID,epsw
  71         ret     [d2,d3,a2,a3,exreg1],32