memcheck/tests/amd64-solaris/context_gpr.c

   1 /* Test if values in rax, rbx, rcx, rdx, rsi and rdi are correctly propagated
   2    into and out of a signal handler and also check that the same applies for
   3    uninitialised values and their origins. */
   4
   5 #include <assert.h>
   6 #include <signal.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <sys/regset.h>
  11 #include <sys/syscall.h>
  12 #include <ucontext.h>
  13
  14 static siginfo_t si;
  15 static ucontext_t uc;
  16 /* x0 is always zero, but is visible to Valgrind as uninitialised. */
  17 static long x0;
  18
  19 void break_out(void);
  20
  21 static void sighandler(int sig, siginfo_t *sip, void *arg)
  22 {
  23    ucontext_t *ucp = (ucontext_t *) arg;
  24
  25    si = *sip;
  26    uc = *ucp;
  27
  28    ucp->uc_mcontext.gregs[REG_RCX] = x0;
  29
  30    /* Break out of the endless loop. */
  31    *(uintptr_t*)&ucp->uc_mcontext.gregs[REG_RIP] = (uintptr_t)break_out;
  32 }
  33
  34 int main(void)
  35 {
  36    struct sigaction sa;
  37    long rax, rbx, rcx, rdx, rsi, rdi;
  38    long y0;
  39
  40    /* Uninitialised, but we know px[0] is 0x0. */
  41    long *px = malloc(sizeof(*px));
  42    x0 = px[0];
  43
  44    /* Uninitialised, but we know py[0] is 0x0. */
  45    long *py = malloc(sizeof(*py));
  46    y0 = py[0];
  47
  48    sa.sa_sigaction = sighandler;
  49    sa.sa_flags = SA_SIGINFO;
  50    if (sigfillset(&sa.sa_mask)) {
  51       perror("sigfillset");
  52       return 1;
  53    }
  54    if (sigaction(SIGALRM, &sa, NULL)) {
  55       perror("sigaction");
  56       return 1;
  57    }
  58
  59    alarm(2);
  60
  61    __asm__ __volatile__(
  62       /* Set values in general purpose registers. */
  63       "movq   $0xf0, %%rax\n"
  64       "movq   %[y0], %%rbx\n"
  65       "movq   $0xf1, %%rcx\n"
  66       "movq   $0xf2, %%rdx\n"
  67       "movq   $0xf3, %%rsi\n"
  68       "movq   $0xf4, %%rdi\n"
  69
  70       /* Loopity loop, this is where the SIGALRM is triggered. */
  71       "1:\n"
  72       "jmp    1b\n"
  73
  74       "break_out:\n"
  75       : "=a" (rax), "=b" (rbx), "=c" (rcx), "=d" (rdx), "=S" (rsi),
  76         "=D" (rdi)
  77       : [y0] "m" (y0)
  78       : "cc", "memory");
  79
  80    printf("Values in the signal handler:\n");
  81    printf("  rax=%#lx, rcx=%#lx, rdx=%#lx, rsi=%#lx, rdi=%#lx\n",
  82           uc.uc_mcontext.gregs[REG_RAX], uc.uc_mcontext.gregs[REG_RCX],
  83           uc.uc_mcontext.gregs[REG_RDX], uc.uc_mcontext.gregs[REG_RSI],
  84           uc.uc_mcontext.gregs[REG_RDI]);
  85    /* Check that rbx contains an uninitialised value (origin is py[0]). */
  86    if (uc.uc_mcontext.gregs[REG_RBX])
  87       assert(0);
  88
  89    printf("Values after the return from the signal handler:\n");
  90    printf("  rax=%#lx, rdx=%#lx, rsi=%#lx, rdi=%#lx\n", rax, rdx, rsi, rdi);
  91    /* Check that rbx and rcx contain uninitialised values (origin is py[0]
  92       and px[0], respectively). */
  93    if (rbx || rcx)
  94       assert(0);
  95
  96    return 0;
  97 }
  98