memcheck/tests/x86-solaris/context_eflags2.c

   1 /* x86 variant of the amd64-solaris/context_rflags2.c test. */
   2
   3 #include <assert.h>
   4 #include <signal.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8 #include <sys/regset.h>
   9 #include <sys/syscall.h>
  10 #include <ucontext.h>
  11
  12 #define OBIT(eflags) (!!((eflags) & (1 << 11)))
  13 #define SBIT(eflags) (!!((eflags) & (1 << 7)))
  14
  15 static siginfo_t si;
  16 static ucontext_t uc;
  17
  18 void break_out(void);
  19
  20 static void sighandler(int sig, siginfo_t *sip, void *arg)
  21 {
  22    ucontext_t *ucp = (ucontext_t *) arg;
  23
  24    si = *sip;
  25    uc = *ucp;
  26
  27    /* Break out of the endless loop. */
  28    *(uintptr_t*)&ucp->uc_mcontext.gregs[EIP] = (uintptr_t)break_out;
  29 }
  30
  31 int main(void)
  32 {
  33    struct sigaction sa;
  34    int eflags;
  35    int x1;
  36
  37    /* Uninitialised, but we know px[0] is 0x0. */
  38    int *px = malloc(sizeof(*px));
  39    x1 = px[0] + 1;
  40
  41    sa.sa_sigaction = sighandler;
  42    sa.sa_flags = SA_SIGINFO;
  43    if (sigfillset(&sa.sa_mask)) {
  44       perror("sigfillset");
  45       return 1;
  46    }
  47    if (sigaction(SIGALRM, &sa, NULL)) {
  48       perror("sigaction");
  49       return 1;
  50    }
  51
  52    alarm(2);
  53
  54    __asm__ __volatile__(
  55       /* Set overflow and sign flags. */
  56       "movl   %[x1], %%edx\n"
  57       "addl   $0x7fffffff, %%edx\n"
  58
  59       /* Loopity loop, this is where the SIGALRM is triggered. */
  60       "1:\n"
  61       "jmp    1b\n"
  62
  63       "break_out:\n"
  64       "pushfl\n"
  65       "popl   %%edx\n"
  66       : "=d" (eflags)
  67       : [x1] "m" (x1)
  68       : "cc", "memory");
  69
  70    /* Check that the overflow and sign flags are uninitialised.
  71
  72       Note: This actually fails because the eflags are only approximate
  73       (always initialised) in the signal handler. */
  74    if (!OBIT(uc.uc_mcontext.gregs[EFL]) || !SBIT(uc.uc_mcontext.gregs[EFL]))
  75       assert(0);
  76
  77    /* Check that the overflow and sign flags are uninitialised. */
  78    if (!OBIT(eflags) || !SBIT(eflags))
  79       assert(0);
  80
  81    return 0;
  82 }
  83