src/lwp/process.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /* process.c - manage lwp context switches be means of setjmp/longjmp. */
  11
  12 #include <afsconfig.h>
  13 #include <afs/param.h>
  14
  15 RCSID("$Header$");
  16
  17 #include <stdio.h>
  18 #include <assert.h>
  19 #include "lwp.h"
  20 #ifdef HAVE_STDLIB_H
  21 #include <stdlib.h>
  22 #endif
  23
  24 #if defined(AFS_OSF_ENV) || defined(AFS_S390_LINUX20_ENV)
  25 extern int PRE_Block;              /* used in lwp.c and process.s */
  26 #else
  27 extern char PRE_Block;             /* used in lwp.c and process.s */
  28 #endif
  29
  30 #if defined(USE_UCONTEXT) && defined(HAVE_UCONTEXT_H)
  31
  32 afs_int32
  33 savecontext(ep, savearea, newsp)
  34 char    (*ep)();
  35 struct lwp_context *savearea;
  36 char*   newsp;
  37 {
  38 #if defined(AFS_IA64_LINUX20_ENV)
  39         register unsigned long sp __asm__("r12");
  40 #else
  41 #error  "You need to update stack pointer register for this platform"
  42 #endif
  43
  44         PRE_Block = 1;
  45
  46         savearea->state = 0;
  47         getcontext(&savearea->ucontext);
  48         savearea->topstack = sp;
  49         switch (savearea->state)
  50         {
  51                 case 0:
  52                         if (newsp)
  53                         {
  54                                 ucontext_t thread;
  55
  56                                 getcontext(&thread);
  57                                 thread.uc_stack.ss_sp = newsp - AFS_LWP_MINSTACKSIZE + sizeof(void *) + sizeof(void *);
  58                                 thread.uc_stack.ss_size = AFS_LWP_MINSTACKSIZE - sizeof(void *);
  59                                 makecontext(&thread, ep, 0);
  60                                 setcontext(&thread);
  61                         }
  62                         else
  63                                 (*ep)();
  64                         break;
  65                 case 2:
  66                         break;
  67         }
  68         return 0;
  69 }
  70
  71 void
  72 returnto(savearea)
  73 struct lwp_context *savearea;
  74 {
  75         PRE_Block = 0;
  76
  77         savearea->state = 2;
  78         setcontext(&savearea->ucontext);
  79 }
  80
  81 #else
  82
  83 /*
  84  * Magic stack pointer
  85  */
  86 #if     defined(AFS_SGI64_ENV)
  87 # ifdef _BSD_COMPAT
  88 #  define LWP_SP 34
  89 # else
  90 #  define LWP_SP JB_SP
  91 # endif
  92 #elif   defined(AFS_HPUX_ENV)
  93 #define LWP_SP  1
  94 #elif   defined(AFS_LINUX20_ENV)
  95 #if defined(AFS_PPC_LINUX20_ENV)
  96 #define LWP_SP 0
  97 #elif   defined(AFS_I386_LINUX20_ENV)
  98 #define LWP_SP 4
  99 #elif   defined(AFS_S390_LINUX20_ENV)
 100 #define LWP_SP 9
 101 #define LWP_FP 5
 102 #elif   defined(AFS_SPARC_LINUX20_ENV)
 103 #define LWP_SP 0
 104 #define LWP_FP 1
 105 #elif   defined(AFS_SPARC64_LINUX20_ENV) && defined(AFS_32BIT_USR_ENV)
 106 #define LWP_SP 0
 107 #define LWP_FP 1
 108 #elif defined(AFS_ALPHA_LINUX20_ENV)
 109 #define LWP_SP 8
 110 #define LWP_FP 7
 111 #elif defined(AFS_PARISC_LINUX24_ENV)
 112 #define LWP_SP 19
 113 #else
 114 #error Unsupported linux LWP system type.
 115 #endif
 116 #elif   defined(AFS_X86_FBSD_ENV)
 117 #define LWP_SP 4
 118 #elif   defined(AFS_DARWIN_ENV)
 119 #define LWP_SP 16
 120 #else
 121      Need offset to SP in jmp_buf for this platform.
 122 #endif
 123
 124 /**
 125   * On SGIs the type of the elements of the array passed to setjmp
 126   * differs based on the ISA chosen. It is int for mips1 and mips2 and
 127   * __uint64_t for mips3 and mips4
 128   */
 129
 130 #ifdef AFS_SGI64_ENV
 131 #if (_MIPS_ISA == _MIPS_ISA_MIPS3 || _MIPS_ISA == _MIPS_ISA_MIPS4)
 132 typedef __uint64_t jmp_buf_type;
 133 #endif
 134 #else
 135 #ifdef AFS_ALPHA_LINUX20_ENV
 136 typedef long jmp_buf_type;
 137 #else
 138 typedef int jmp_buf_type;
 139 #endif /*AFS_ALPHA_LINUX20_ENV*/
 140 #endif /*SGI*/
 141
 142 static jmp_buf  jmp_tmp;
 143 static char     (*EP)();
 144 static int      rc;
 145 static jmp_buf_type  *jmpBuffer;
 146
 147 afs_int32 savecontext(ep, savearea, sp)
 148 char    (*ep)();
 149 struct lwp_context *savearea;
 150 char*   sp;
 151 {
 152         int code;
 153
 154         PRE_Block = 1;
 155         EP = ep;
 156
 157         code =  setjmp(savearea->setjmp_buffer);
 158         jmpBuffer = (jmp_buf_type *)savearea->setjmp_buffer;
 159         savearea->topstack = (char*)jmpBuffer[LWP_SP];
 160
 161 #if     defined(DEBUG)
 162         {
 163             int i, *ptr = (int*)savearea->setjmp_buffer;
 164             printf("savecontext\n");
 165             for ( i=0; i < 5; i++)
 166                 printf("(%d) 0x%x   ",i, ptr[i]);
 167             printf("\n");
 168             for ( i=5; i < 10; i++)
 169                 printf("(%d) 0x%x   ",i, ptr[i]);
 170             printf("\n");
 171         }
 172 #endif
 173         switch ( code )
 174         {
 175                 case 0: if ( !sp )
 176                         (*EP)();
 177                         else
 178                         {
 179                                 rc = setjmp(jmp_tmp);
 180                                 switch ( rc )
 181                                 {
 182                                 case 0: jmpBuffer = (jmp_buf_type *)jmp_tmp;
 183                                         jmpBuffer[LWP_SP] = (jmp_buf_type)sp;
 184 #if defined(AFS_S390_LINUX20_ENV) || defined(AFS_SPARC_LINUX20_ENV) || (defined(AFS_SPARC64_LINUX20_ENV) && defined(AFS_32BIT_USR_ENV))
 185                                         jmpBuffer[LWP_FP] = (jmp_buf_type)sp;
 186 #endif
 187                                         longjmp(jmp_tmp,1);
 188                                         break;
 189                                 case 1: (*EP)();
 190                                         assert(0); /* never returns */
 191                                         break;
 192                                 default:
 193                                         perror("Error in setjmp1\n");
 194                                         exit(2);
 195                                 }
 196                         }
 197                         break;
 198                case 2: /* restoring frame */
 199                         break;
 200
 201                default:
 202                         perror("Error in setjmp2 : restoring\n");
 203                         exit(3);
 204         }
 205         return 0;
 206 }
 207
 208 afs_int32 returnto(savearea)
 209 struct lwp_context *savearea;
 210 {
 211 #if     defined(DEBUG)
 212         int i, *ptr = savearea->setjmp_buffer;
 213
 214         printf("Returning to \n");
 215         for ( i=0; i < 5; i++)
 216                 printf("(%d) 0x%x   ",i, ptr[i]);
 217         printf("\n");
 218         for ( i=5; i < 10; i++)
 219                 printf("(%d) 0x%x   ",i, ptr[i]);
 220         printf("\n");
 221 #endif
 222         PRE_Block = 0;
 223         longjmp(savearea->setjmp_buffer, 2);
 224         return 0;
 225 }
 226
 227 #endif