include/asm-sh/switch.h

   1 /*
   2  * Copyright (C) 2011 Philippe Gerum <rpm@xenomai.org>.
   3  *
   4  * Xenomai is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Xenomai is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with Xenomai; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  17  * 02111-1307, USA.
  18  */
  19
  20 #ifndef _XENO_ASM_SH_SWITCH_H
  21 #define _XENO_ASM_SH_SWITCH_H
  22
  23 #ifndef __KERNEL__
  24 #error "Pure kernel header included from user-space!"
  25 #endif
  26
  27 #include <asm/system.h>
  28
  29 /*
  30  * Most of this code was lifted from the regular Linux task switching
  31  * code. A provision for handling Xenomai-originated kernel threads
  32  * (aka "hybrid scheduling" is added).
  33  */
  34 #define xnarch_switch_threads(otcb, itcb, prev, next)           \
  35         ({                                                      \
  36         register u32 *__ts1 __asm__ ("r1");                     \
  37         register u32 *__ts2 __asm__ ("r2");                     \
  38         register u32 *__ts4 __asm__ ("r4");                     \
  39         register u32 *__ts5 __asm__ ("r5");                     \
  40         register u32 *__ts6 __asm__ ("r6");                     \
  41         register u32 __ts7 __asm__ ("r7");                      \
  42         struct task_struct *__last = prev;                      \
  43         struct xnarchtcb *__ltcb = otcb;                        \
  44                                                                 \
  45         if (otcb->tsp == &prev->thread &&                       \
  46             is_dsp_enabled(prev))                               \
  47                 __save_dsp(prev);                               \
  48                                                                 \
  49         __ts1 = (u32 *)&otcb->tsp->sp;                          \
  50         __ts2 = (u32 *)&otcb->tsp->pc;                          \
  51         __ts4 = (u32 *)prev;                                    \
  52         __ts5 = (u32 *)next;                                    \
  53         __ts6 = (u32 *)&itcb->tsp->sp;                          \
  54         __ts7 = itcb->tsp->pc;                                  \
  55                                                                 \
  56         __asm__ __volatile__ (                                  \
  57                 ".balign 4\n\t"                                 \
  58                 "stc.l  gbr, @-r15\n\t"                         \
  59                 "sts.l  pr, @-r15\n\t"                          \
  60                 "mov.l  r8, @-r15\n\t"                          \
  61                 "mov.l  r9, @-r15\n\t"                          \
  62                 "mov.l  r10, @-r15\n\t"                         \
  63                 "mov.l  r11, @-r15\n\t"                         \
  64                 "mov.l  r12, @-r15\n\t"                         \
  65                 "mov.l  r13, @-r15\n\t"                         \
  66                 "mov.l  r14, @-r15\n\t"                         \
  67                 "mov.l  r15, @r1\t! save SP\n\t"                \
  68                 "mov.l  @r6, r15\t! change to new stack\n\t"    \
  69                 "mova   1f, %0\n\t"                             \
  70                 "mov.l  %0, @r2\t! save PC\n\t"                 \
  71                 "mov    #0, r8\n\t"                             \
  72                 "cmp/eq r5, r8\n\t"                             \
  73                 "bt/s   3f\n\t"                                 \
  74                 " lds   r7, pr\t!  return to saved PC\n\t"      \
  75                 "mov.l  2f, %0\n\t"                             \
  76                 "jmp    @%0\t! call __switch_to\n\t"            \
  77                 " nop\t\n\t"                                    \
  78                 "3:\n\t"                                        \
  79                 "rts\n\t"                                       \
  80                 ".balign        4\n"                            \
  81                 "2:\n\t"                                        \
  82                 ".long  __switch_to\n"                          \
  83                 "1:\n\t"                                        \
  84                 "mov.l  @r15+, r14\n\t"                         \
  85                 "mov.l  @r15+, r13\n\t"                         \
  86                 "mov.l  @r15+, r12\n\t"                         \
  87                 "mov.l  @r15+, r11\n\t"                         \
  88                 "mov.l  @r15+, r10\n\t"                         \
  89                 "mov.l  @r15+, r9\n\t"                          \
  90                 "mov.l  @r15+, r8\n\t"                          \
  91                 "lds.l  @r15+, pr\n\t"                          \
  92                 "ldc.l  @r15+, gbr\n\t"                         \
  93                 : "=z" (__last)                                 \
  94                 : "r" (__ts1), "r" (__ts2), "r" (__ts4),        \
  95                   "r" (__ts5), "r" (__ts6), "r" (__ts7)         \
  96                 : "r3", "t");                                   \
  97                                                                 \
  98         if (__ltcb->tsp == &__last->thread &&                   \
  99             is_dsp_enabled(__last))                             \
 100                 __restore_dsp(__last);                          \
 101                                                                 \
 102         __last;                                                 \
 103         })
 104
 105 #endif /* _XENO_ASM_SH_SWITCH_H */