kernel/generic/include/context.h

   1 /*
   2  * Copyright (c) 2001-2004 Jakub Jermar
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup generic
  30  * @{
  31  */
  32 /** @file
  33  */
  34
  35 #ifndef KERN_CONTEXT_H_
  36 #define KERN_CONTEXT_H_
  37
  38 #include <arch/types.h>
  39 #include <typedefs.h>
  40 #include <arch/context.h>
  41
  42
  43 #ifndef context_set
  44 #define context_set(c, _pc, stack, size)        \
  45         (c)->pc = (uintptr_t) (_pc);            \
  46         (c)->sp = ((uintptr_t) (stack)) + (size) - SP_DELTA;
  47 #endif /* context_set */
  48
  49 extern int context_save_arch(context_t *c);
  50 extern void context_restore_arch(context_t *c) __attribute__ ((noreturn));
  51
  52 /** Save register context.
  53  *
  54  * Save current register context (including stack pointers)
  55  * to context structure.
  56  *
  57  * Note that call to context_restore() will return at the same
  58  * address as the corresponding call to context_save().
  59  *
  60  * This MUST be a macro, gcc -O0 does not inline functions even
  61  * if they are marked inline and context_save_arch must be called
  62  * from level <= that when context_restore is called.
  63  *
  64  * @param c Context structure.
  65  *
  66  * @return context_save() returns 1, context_restore() returns 0.
  67  */
  68 #define context_save(c)   context_save_arch(c)
  69
  70 /** Restore register context.
  71  *
  72  * Restore previously saved register context (including stack pointers)
  73  * from context structure.
  74  *
  75  * Note that this function does not normally return.
  76  * Instead, it returns at the same address as the
  77  * corresponding call to context_save(), the only
  78  * difference being return value.
  79  *
  80  * Note that content of any local variable defined by
  81  * the caller of context_save() is undefined after
  82  * context_restore().
  83  *
  84  * @param c Context structure.
  85  */
  86 static inline void context_restore(context_t *c)
  87 {
  88         context_restore_arch(c);
  89 }
  90
  91 #endif
  92
  93 /** @}
  94  */