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 #elif defined(AFS_AMD64_LINUX24_ENV)
  41         register unsigned long sp __asm__("sp");
  42 #elif defined(AFS_HPUX1122_ENV)
  43 /* don't need anything special, will use
  44  * ucontext.uc_stack.ss_sp as it matches r12.
  45  * This should also work for Linux,
  46  * but dont have system to test DEE
  47  */
  48 #else
  49 #error  "You need to update stack pointer register for this platform"
  50 #endif
  51
  52         PRE_Block = 1;
  53
  54         savearea->state = 0;
  55         getcontext(&savearea->ucontext);
  56 #if defined(AFS_HPUX1122_ENV)
  57     savearea->topstack = savearea->ucontext.uc_stack.ss_sp;
  58 #else
  59         savearea->topstack = sp;
  60 #endif
  61         switch (savearea->state)
  62         {
  63                 case 0:
  64                         if (newsp)
  65                         {
  66                                 ucontext_t thread;
  67
  68                                 getcontext(&thread);
  69                                 thread.uc_stack.ss_sp = newsp - AFS_LWP_MINSTACKSIZE + sizeof(void *) + sizeof(void *);
  70                                 thread.uc_stack.ss_size = AFS_LWP_MINSTACKSIZE - sizeof(void *);
  71                                 makecontext(&thread, ep, 0);
  72                                 setcontext(&thread);
  73                         }
  74                         else
  75                                 (*ep)();
  76                         break;
  77                 case 2:
  78                         break;
  79         }
  80         return 0;
  81 }
  82
  83 void
  84 returnto(savearea)
  85 struct lwp_context *savearea;
  86 {
  87         PRE_Block = 0;
  88
  89         savearea->state = 2;
  90         setcontext(&savearea->ucontext);
  91 }
  92
  93 #else
  94
  95 /*
  96  * Magic stack pointer
  97  */
  98 #if     defined(AFS_SGI64_ENV)
  99 # ifdef _BSD_COMPAT
 100 #  define LWP_SP 34
 101 # else
 102 #  define LWP_SP JB_SP
 103 # endif
 104 #elif   defined(AFS_HPUX_ENV)
 105 #define LWP_SP  1
 106 #elif   defined(AFS_LINUX20_ENV)
 107 #if defined(AFS_PPC_LINUX20_ENV)
 108 #define LWP_SP 0
 109 #elif   defined(AFS_I386_LINUX20_ENV)
 110 #define LWP_SP 4
 111 #elif   defined(AFS_S390_LINUX20_ENV)
 112 #define LWP_SP 9
 113 #define LWP_FP 5
 114 #elif   defined(AFS_SPARC_LINUX20_ENV)
 115 #define LWP_SP 0
 116 #define LWP_FP 1
 117 #elif   defined(AFS_SPARC64_LINUX20_ENV) && defined(AFS_32BIT_USR_ENV)
 118 #define LWP_SP 0
 119 #define LWP_FP 1
 120 #elif defined(AFS_ALPHA_LINUX20_ENV)
 121 #define LWP_SP 8
 122 #define LWP_FP 7
 123 #elif defined(AFS_PARISC_LINUX24_ENV)
 124 #define LWP_SP 19
 125 #else
 126 #error Unsupported linux LWP system type.
 127 #endif
 128 #elif   defined(AFS_X86_FBSD_ENV)
 129 #define LWP_SP 4
 130 #elif   defined(AFS_DARWIN_ENV)
 131 #define LWP_SP 16
 132 #else
 133      Need offset to SP in jmp_buf for this platform.
 134 #endif
 135
 136 /**
 137   * On SGIs the type of the elements of the array passed to setjmp
 138   * differs based on the ISA chosen. It is int for mips1 and mips2 and
 139   * __uint64_t for mips3 and mips4
 140   */
 141
 142 #ifdef AFS_SGI64_ENV
 143 #if (_MIPS_ISA == _MIPS_ISA_MIPS3 || _MIPS_ISA == _MIPS_ISA_MIPS4)
 144 typedef __uint64_t jmp_buf_type;
 145 #endif
 146 #else
 147 #ifdef AFS_ALPHA_LINUX20_ENV
 148 typedef long jmp_buf_type;
 149 #else
 150 typedef int jmp_buf_type;
 151 #endif /*AFS_ALPHA_LINUX20_ENV*/
 152 #endif /*SGI*/
 153
 154 static jmp_buf  jmp_tmp;
 155 static char     (*EP)();
 156 static int      rc;
 157 static jmp_buf_type  *jmpBuffer;
 158
 159 afs_int32 savecontext(ep, savearea, sp)
 160 char    (*ep)();
 161 struct lwp_context *savearea;
 162 char*   sp;
 163 {
 164         int code;
 165
 166         PRE_Block = 1;
 167         EP = ep;
 168
 169         code =  setjmp(savearea->setjmp_buffer);
 170         jmpBuffer = (jmp_buf_type *)savearea->setjmp_buffer;
 171         savearea->topstack = (char*)jmpBuffer[LWP_SP];
 172
 173 #if     defined(DEBUG)
 174         {
 175             int i, *ptr = (int*)savearea->setjmp_buffer;
 176             printf("savecontext\n");
 177             for ( i=0; i < 5; i++)
 178                 printf("(%d) 0x%x   ",i, ptr[i]);
 179             printf("\n");
 180             for ( i=5; i < 10; i++)
 181                 printf("(%d) 0x%x   ",i, ptr[i]);
 182             printf("\n");
 183         }
 184 #endif
 185         switch ( code )
 186         {
 187                 case 0: if ( !sp )
 188                         (*EP)();
 189                         else
 190                         {
 191                                 rc = setjmp(jmp_tmp);
 192                                 switch ( rc )
 193                                 {
 194                                 case 0: jmpBuffer = (jmp_buf_type *)jmp_tmp;
 195                                         jmpBuffer[LWP_SP] = (jmp_buf_type)sp;
 196 #if defined(AFS_S390_LINUX20_ENV) || defined(AFS_SPARC_LINUX20_ENV) || (defined(AFS_SPARC64_LINUX20_ENV) && defined(AFS_32BIT_USR_ENV))
 197                                         jmpBuffer[LWP_FP] = (jmp_buf_type)sp;
 198 #endif
 199                                         longjmp(jmp_tmp,1);
 200                                         break;
 201                                 case 1: (*EP)();
 202                                         assert(0); /* never returns */
 203                                         break;
 204                                 default:
 205                                         perror("Error in setjmp1\n");
 206                                         exit(2);
 207                                 }
 208                         }
 209                         break;
 210                case 2: /* restoring frame */
 211                         break;
 212
 213                default:
 214                         perror("Error in setjmp2 : restoring\n");
 215                         exit(3);
 216         }
 217         return 0;
 218 }
 219
 220 afs_int32 returnto(savearea)
 221 struct lwp_context *savearea;
 222 {
 223 #if     defined(DEBUG)
 224         int i, *ptr = savearea->setjmp_buffer;
 225
 226         printf("Returning to \n");
 227         for ( i=0; i < 5; i++)
 228                 printf("(%d) 0x%x   ",i, ptr[i]);
 229         printf("\n");
 230         for ( i=5; i < 10; i++)
 231                 printf("(%d) 0x%x   ",i, ptr[i]);
 232         printf("\n");
 233 #endif
 234         PRE_Block = 0;
 235         longjmp(savearea->setjmp_buffer, 2);
 236         return 0;
 237 }
 238
 239 #endif