mirror of
https://github.com/ioacademy-jikim/debugging
synced 2025-06-09 00:46:12 +00:00
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
/* Test if x87 FP valus are correctly propagated in and out of a signal
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handler and also check that the same applies for uninitialised values and
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their origins. */
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#include <assert.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <sys/ucontext.h>
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static siginfo_t si;
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static ucontext_t uc;
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static float inhandler[8];
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static void sighandler(int sig, siginfo_t *sip, ucontext_t *ucp)
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{
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int i;
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si = *sip;
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uc = *ucp;
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/* Reset the FP stack so it's possible to push other values onto it. (It
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is fully filled in main() before triggering the signal handler). Note
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that VEX also clears all FP values when the finit instruction is
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executed. This provides another level of validation that the restore
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code is correct. */
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__asm__ __volatile__(
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"finit\n");
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/* Convert 80b values in mcontext to 32b values in the inhandler array. */
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for (i = 0; i < 8; i++) {
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__asm__ __volatile__(
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"fldt %[in]\n"
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"fstps %[out]\n"
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: [out] "=m" (inhandler[i])
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: [in] "m" (*(char*)&ucp->uc_mcontext.fpregs.fp_reg_set.fpchip_state.st[i]));
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}
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}
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int main(void)
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{
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struct sigaction sa;
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pid_t pid;
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float out[8];
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float x0;
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/* Uninitialised, but we know px[0] is 0x0. */
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float *px = malloc(sizeof(*px));
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x0 = px[0];
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sa.sa_handler = sighandler;
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sa.sa_flags = SA_SIGINFO;
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if (sigfillset(&sa.sa_mask)) {
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perror("sigfillset");
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return 1;
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}
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if (sigaction(SIGUSR1, &sa, NULL)) {
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perror("sigaction");
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return 1;
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}
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pid = getpid();
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__asm__ __volatile__(
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/* Set values in the FP stack. */
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"flds %[x0]\n"
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"fld1\n"
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"flds %[x0]\n"
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"fld1\n"
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"flds %[x0]\n"
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"fld1\n"
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"flds %[x0]\n"
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"fld1\n"
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/* Trigger the signal handler. */
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"syscall\n"
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"fstps 0x00 + %[out]\n"
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"fstps 0x04 + %[out]\n"
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"fstps 0x08 + %[out]\n"
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"fstps 0x0c + %[out]\n"
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"fstps 0x10 + %[out]\n"
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"fstps 0x14 + %[out]\n"
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"fstps 0x18 + %[out]\n"
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"fstps 0x1c + %[out]\n"
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: [out] "=m" (out[0])
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: "a" (SYS_kill), "D" (pid), "S" (SIGUSR1), [x0] "m" (x0)
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: "rdx", "cc", "memory");
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printf("Values in the signal handler:\n");
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printf(" fp[0]=%f, fp[2]=%f, fp[4]=%f, fp[6]=%f\n",
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inhandler[0], inhandler[2], inhandler[4], inhandler[6]);
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/* Check that inhandler[1], inhandler[3], inhandler[5] and inhandler[7]
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contain uninitialised values (origin is px[0]). */
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if (inhandler[1] || inhandler[3] || inhandler[5] || inhandler[7])
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assert(0);
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printf("Values after the return from the signal handler:\n");
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printf(" fp[0]=%f, fp[2]=%f, fp[4]=%f, fp[6]=%f\n",
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out[0], out[2], out[4], out[6]);
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/* Check that out[1], out[3], out[5] and out[7] contain uninitialised
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values (origin is px[0]). */
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if (out[1] || out[3] || out[5] || out[7])
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assert(0);
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return 0;
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}
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