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
  65 sig_segv(int sig_no)
  66 {
  67    /* jumping to error handling in VAssert_IsInVM. */
  68    siglongjmp(segv_jmp, 1);
  69 }
  70
  71
  72 /*
  73  *---------------------------------------------------------------------
  74  *
  75  * VAssert_IsInVM --
  76  *
  77  *    Check if we are in virtual world.
  78  *
  79  * Results:
  80  *
  81  *    Return TRUE on success, or FALSE on failure.
  82  *
  83  * Side effects:
  84  *    None.
  85  *
  86  *---------------------------------------------------------------------
  87  */
  88
  89 static Bool
  90 VAssert_IsInVM(void)
  91 {
  92    uint32 eax, ebx, ecx, edx;
  93    static Bool inVM = FALSE;
  94    static Bool tested = FALSE;
  95    if (!tested) {
  96       /* Error handling. */
  97       if (sigsetjmp(segv_jmp, 0) != 0) {
  98          signal(SIGSEGV, SIG_DFL);
  99          inVM = FALSE;
 100          return inVM;
 101       }
 102       tested = TRUE;
 103       /* Install custom handler. */
 104       signal(SIGSEGV, sig_segv);
 105       /* Test if we are in a VM. */
 106       libvassert_process_backdoor(0x0a, 0, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 107       signal(SIGSEGV, SIG_DFL);
 108       inVM = TRUE;
 109    }
 110    return inVM;
 111 }
 112
 113
 114 /*
 115  *---------------------------------------------------------------------
 116  *
 117  * VAssert_Init --
 118  *
 119  *    Tell vmx that vassert is inited.
 120  *
 121  * Results:
 122  *
 123  *    Return 0 on success, or -1 on failure.
 124  *
 125  * Side effects:
 126  *    None
 127  *
 128  *---------------------------------------------------------------------
 129  */
 130
 131 char
 132 VAssert_Init(void)
 133 {
 134    uint32 eax, ebx, ecx, edx;
 135    VA page_address = (VA) &vassert_state.inReplay;
 136    if (!VAssert_IsInVM()) {
 137       return -1;
 138    }
 139    bzero((char*) &vassert_state, sizeof vassert_state);
 140 #ifndef __minix
 141    /* Lock the page. */
 142    if (mlock(&vassert_state, sizeof vassert_state)) {
 143       return -1;
 144    }
 145 #endif
 146
 147    libvassert_process_backdoor(CMD_SET_ADDRESS, page_address,
 148         MAGIC_PORT|(1<<16), &eax, &ebx, &ecx, &edx);
 149
 150    return (eax != -1) ? 0 : -1;
 151 }
 152
 153
 154 /*
 155  *---------------------------------------------------------------------
 156  *
 157  * VAssert_Uninit --
 158  *
 159  *    Tell vmx that vassert is finalized.
 160  *
 161  * Results:
 162  *
 163  *    Return 0 on success, or -1 on failure.
 164  *
 165  * Side effects:
 166  *    None
 167  *
 168  *---------------------------------------------------------------------
 169  */
 170
 171 char
 172 VAssert_Uninit(void)
 173 {
 174    unsigned int eax, ebx, ecx, edx;
 175    if (!VAssert_IsInVM()) {
 176       return -1;
 177    }
 178    libvassert_process_backdoor(CMD_SET_ADDRESS, 0, MAGIC_PORT|(0<<16), &eax, &ebx, &ecx, &edx);
 179    return (eax != -1) ? 0 : 1;
 180 }
 181
 182
 183 /*
 184  *---------------------------------------------------------------------
 185  *
 186  * VAssert_LogMain --
 187  *
 188  *    Print message to a text file on host side.
 189  *
 190  * Results:
 191  *    None
 192  *
 193  * Side effects:
 194  *    Write to a text file with fixed name.
 195  *    If the file exists, host UI will ask for append/replace/ignore
 196  *
 197  *---------------------------------------------------------------------
 198  */
 199
 200 void
 201 VAssert_LogMain(const char *format, ...)
 202 {
 203    unsigned int eax, ebx, ecx, edx;
 204    char buf[LOG_MAX];
 205    unsigned int len = 0;
 206    va_list ap;
 207    va_start(ap, format);
 208    len = vsnprintf(buf, LOG_MAX, format, ap);
 209    va_end(ap);
 210    __asm__ __volatile__("cld; rep outsb;"
 211                         : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx)
 212                         : "0"(MAGIC_CMD), "1"(CMD_LOG), "2"(len), "d"(HIGH_BAND_PORT), "S"(buf)
 213                         : "memory"
 214                        );
 215 }
 216
 217
 218 /*
 219  *---------------------------------------------------------------------
 220  *
 221  * VAssert_GoLiveMain --
 222  *
 223  *    Make the vm which is in replay exit replay.
 224  *
 225  * Results:
 226  *    None
 227  *
 228  * Side effects:
 229  *    Replay is stopped.
 230  *
 231  *---------------------------------------------------------------------
 232  */
 233
 234 void
 235 VAssert_GoLiveMain()
 236 {
 237    unsigned int eax, ebx, ecx, edx;
 238    vassert_state.inReplay = 0;
 239    libvassert_process_backdoor(CMD_GO_LIVE, 0, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 240 }
 241
 242
 243 /*
 244  *---------------------------------------------------------------------
 245  *
 246  * VAssert_ReturnToReplayMain --
 247  *
 248  *    Called after the custom work is done, and replay is to continue.
 249  *
 250  * Results:
 251  *    None
 252  *
 253  * Side effects:
 254  *    Replay is continued from pause.
 255  *
 256  *---------------------------------------------------------------------
 257  */
 258
 259 void
 260 VAssert_ReturnToReplayMain()
 261 {
 262    unsigned int eax, ebx, ecx, edx;
 263    libvassert_process_backdoor(CMD_RETURN_REPLAY, 0, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 264 }
 265
 266
 267 /*
 268  *---------------------------------------------------------------------
 269  *
 270  * VAssert_SetRecordingMain --
 271  *
 272  *    Ask vmx for starting or stopping recording.
 273  *
 274  * Results:
 275  *
 276  *    Return TRUE on success, or FALSE on failure.
 277  *
 278  * Side effects:
 279  *    Recording is started or stopped.
 280  *
 281  *---------------------------------------------------------------------
 282  */
 283
 284 char
 285 VAssert_SetRecordingMain(char start)
 286 {
 287    uint32 eax, ebx, ecx, edx;
 288    if (!VAssert_IsInVM()) {
 289       return FALSE;
 290    }
 291    libvassert_process_backdoor(CMD_SET_RECORD, start ? 1 : 2, MAGIC_PORT, &eax, &ebx, &ecx, &edx);
 292    return (eax == 1) ? TRUE : FALSE;
 293 }
 294