minix/lib/libvassert/vassert.c

   1 #include <string.h>
   2 #include <stdarg.h>
   3 #include <signal.h>
   4 #include <setjmp.h>
   5 #include <minix/config.h>
   6 #include <minix/const.h>
   7 #include <minix/ipc.h>
   8 #include <minix/com.h>
   9 #include <minix/syslib.h>
  10 #include <machine/stackframe.h>
  11 #include "vassert.h"
  12
  13 VAssert_StateWrapper vassert_state ALIGNED(VASSERT_PAGE_SIZE);
  14
  15 #define TRUE 1
  16 #define FALSE 0
  17
  18 #define MAGIC_CMD  0x564d5868
  19 #define MAGIC_PORT 0x5658
  20 #define HIGH_BAND_PORT 0x5659
  21
  22 #define BACKDOOR_PORT           51
  23 #define BACKDOOR_HB_PORT        1
  24 #define CMD_SET_ADDRESS         BACKDOOR_PORT|(1<<16)
  25 #define CMD_RETURN_REPLAY       BACKDOOR_PORT|(2<<16)
  26 #define CMD_GO_LIVE             BACKDOOR_PORT|(3<<16)
  27 #define CMD_LOG                 BACKDOOR_HB_PORT|(4<<16)
  28 #define CMD_SET_RECORD          47
  29
  30 #define LOG_MAX 512
  31
  32 typedef char Bool;
  33 typedef unsigned int uint32;
  34 typedef unsigned long long uint64;
  35
  36 #ifdef VM_X86_64
  37 typedef uint64 VA;
  38 #else
  39 typedef uint32 VA;
  40 #endif
  41
  42 static sigjmp_buf segv_jmp;
  43
  44 void libvassert_process_backdoor(uint32, uint32, uint32, reg_t *, reg_t *,
  45                                  reg_t *, reg_t *);
  46
  47 /*
  48  *---------------------------------------------------------------------
  49  *
  50  * sig_segv --
  51  *
  52  *    Customed SEGV signal handler for VAssert_IsInVM.
  53  *
  54  * Results:
  55  *
  56  *    None.
  57  *
  58  * Side effects:
  59  *    None.
  60  *
  61  *---------------------------------------------------------------------
  62  */
  63
  64 static void sig_segv(int sig_no)
  65 {
  66    /* jumping to error handling in VAssert_IsInVM. */
  67    siglongjmp(segv_jmp, 1);
  68 }
  69
  70
  71 /*
  72  *---------------------------------------------------------------------
  73  *
  74  * VAssert_IsInVM --
  75  *
  76  *    Check if we are in virtual world.
  77  *
  78  * Results:
  79  *
  80  *    Return TRUE on success, or FALSE on failure.
  81  *
  82  * Side effects:
  83  *    None.
  84  *
  85  *---------------------------------------------------------------------
  86  */
  87
  88 static Bool VAssert_IsInVM(void)
  89 {
  90    uint32 eax, ebx, ecx, edx;
  91    static Bool inVM = FALSE;
  92    static Bool tested = FALSE;
  93    if (!tested) {
  94       /* Error handling. */
  95       if (sigsetjmp(segv_jmp, 0) != 0) {
  96          signal(SIGSEGV, SIG_DFL);
  97          inVM = FALSE;
  98          return inVM;
  99       }
 100       tested = TRUE;
 101       /* Install custom handler. */
 102       signal(SIGSEGV, sig_segv);
 103       /* Test if we are in a VM. */
 104       libvassert_process_backdoor(0x0a, 0, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 105       signal(SIGSEGV, SIG_DFL);
 106       inVM = TRUE;
 107    }
 108    return inVM;
 109 }
 110
 111
 112 /*
 113  *---------------------------------------------------------------------
 114  *
 115  * VAssert_Init --
 116  *
 117  *    Tell vmx that vassert is inited.
 118  *
 119  * Results:
 120  *
 121  *    Return 0 on success, or -1 on failure.
 122  *
 123  * Side effects:
 124  *    None
 125  *
 126  *---------------------------------------------------------------------
 127  */
 128
 129 char VAssert_Init(void)
 130 {
 131    uint32 eax, ebx, ecx, edx;
 132    VA page_address = (VA) &vassert_state.inReplay;
 133    if (!VAssert_IsInVM()) {
 134       return -1;
 135    }
 136    bzero((char*) &vassert_state, sizeof vassert_state);
 137 #ifndef __minix
 138    /* Lock the page. */
 139    if (mlock(&vassert_state, sizeof vassert_state)) {
 140       return -1;
 141    }
 142 #endif
 143
 144    libvassert_process_backdoor(CMD_SET_ADDRESS, page_address,
 145         MAGIC_PORT|(1<<16), &eax, &ebx, &ecx, &edx);
 146
 147    return (eax != -1) ? 0 : -1;
 148 }
 149
 150
 151 /*
 152  *---------------------------------------------------------------------
 153  *
 154  * VAssert_Uninit --
 155  *
 156  *    Tell vmx that vassert is finalized.
 157  *
 158  * Results:
 159  *
 160  *    Return 0 on success, or -1 on failure.
 161  *
 162  * Side effects:
 163  *    None
 164  *
 165  *---------------------------------------------------------------------
 166  */
 167
 168 char VAssert_Uninit(void)
 169 {
 170    unsigned int eax, ebx, ecx, edx;
 171    if (!VAssert_IsInVM()) {
 172       return -1;
 173    }
 174    libvassert_process_backdoor(CMD_SET_ADDRESS, 0, MAGIC_PORT|(0<<16), &eax, &ebx, &ecx, &edx);
 175    return (eax != -1) ? 0 : 1;
 176 }
 177
 178
 179 /*
 180  *---------------------------------------------------------------------
 181  *
 182  * VAssert_LogMain --
 183  *
 184  *    Print message to a text file on host side.
 185  *
 186  * Results:
 187  *    None
 188  *
 189  * Side effects:
 190  *    Write to a text file with fixed name.
 191  *    If the file exists, host UI will ask for append/replace/ignore
 192  *
 193  *---------------------------------------------------------------------
 194  */
 195
 196 void VAssert_LogMain(const char *format, ...)
 197 {
 198    unsigned int eax, ebx, ecx, edx;
 199    char buf[LOG_MAX];
 200    unsigned int len = 0;
 201    va_list ap;
 202    va_start(ap, format);
 203    len = vsnprintf(buf, LOG_MAX, format, ap);
 204    va_end(ap);
 205    __asm__ __volatile__("cld; rep outsb;"
 206                         : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx)
 207                         : "0"(MAGIC_CMD), "1"(CMD_LOG), "2"(len), "d"(HIGH_BAND_PORT), "S"(buf)
 208                         : "memory"
 209                        );
 210 }
 211
 212
 213 /*
 214  *---------------------------------------------------------------------
 215  *
 216  * VAssert_GoLiveMain --
 217  *
 218  *    Make the vm which is in replay exit replay.
 219  *
 220  * Results:
 221  *    None
 222  *
 223  * Side effects:
 224  *    Replay is stopped.
 225  *
 226  *---------------------------------------------------------------------
 227  */
 228
 229 void VAssert_GoLiveMain(void)
 230 {
 231    unsigned int eax, ebx, ecx, edx;
 232    vassert_state.inReplay = 0;
 233    libvassert_process_backdoor(CMD_GO_LIVE, 0, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 234 }
 235
 236
 237 /*
 238  *---------------------------------------------------------------------
 239  *
 240  * VAssert_ReturnToReplayMain --
 241  *
 242  *    Called after the custom work is done, and replay is to continue.
 243  *
 244  * Results:
 245  *    None
 246  *
 247  * Side effects:
 248  *    Replay is continued from pause.
 249  *
 250  *---------------------------------------------------------------------
 251  */
 252
 253 void VAssert_ReturnToReplayMain(void)
 254 {
 255    unsigned int eax, ebx, ecx, edx;
 256    libvassert_process_backdoor(CMD_RETURN_REPLAY, 0, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 257 }
 258
 259
 260 /*
 261  *---------------------------------------------------------------------
 262  *
 263  * VAssert_SetRecordingMain --
 264  *
 265  *    Ask vmx for starting or stopping recording.
 266  *
 267  * Results:
 268  *
 269  *    Return TRUE on success, or FALSE on failure.
 270  *
 271  * Side effects:
 272  *    Recording is started or stopped.
 273  *
 274  *---------------------------------------------------------------------
 275  */
 276
 277 char VAssert_SetRecordingMain(char start)
 278 {
 279    uint32 eax, ebx, ecx, edx;
 280    if (!VAssert_IsInVM()) {
 281       return FALSE;
 282    }
 283    libvassert_process_backdoor(CMD_SET_RECORD, start ? 1 : 2, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 284    return (eax == 1) ? TRUE : FALSE;
 285 }
 286