tests/tcg/aarch64/bti-crt.inc.c

   1 /*
   2  * Minimal user-environment for testing BTI.
   3  *
   4  * Normal libc is not (yet) built with BTI support enabled,
   5  * and so could generate a BTI TRAP before ever reaching main.
   6  */
   7
   8 #include <stdlib.h>
   9 #include <signal.h>
  10 #include <ucontext.h>
  11 #include <asm/unistd.h>
  12
  13 int main(void);
  14
  15 void _start(void)
  16 {
  17     exit(main());
  18 }
  19
  20 void exit(int ret)
  21 {
  22     register int x0 __asm__("x0") = ret;
  23     register int x8 __asm__("x8") = __NR_exit;
  24
  25     asm volatile("svc #0" : : "r"(x0), "r"(x8));
  26     __builtin_unreachable();
  27 }
  28
  29 /*
  30  * Irritatingly, the user API struct sigaction does not match the
  31  * kernel API struct sigaction.  So for simplicity, isolate the
  32  * kernel ABI here, and make this act like signal.
  33  */
  34 void signal_info(int sig, void (*fn)(int, siginfo_t *, ucontext_t *))
  35 {
  36     struct kernel_sigaction {
  37         void (*handler)(int, siginfo_t *, ucontext_t *);
  38         unsigned long flags;
  39         unsigned long restorer;
  40         unsigned long mask;
  41     } sa = { fn, SA_SIGINFO, 0, 0 };
  42
  43     register int x0 __asm__("x0") = sig;
  44     register void *x1 __asm__("x1") = &sa;
  45     register void *x2 __asm__("x2") = 0;
  46     register int x3 __asm__("x3") = sizeof(unsigned long);
  47     register int x8 __asm__("x8") = __NR_rt_sigaction;
  48
  49     asm volatile("svc #0"
  50                  : : "r"(x0), "r"(x1), "r"(x2), "r"(x3), "r"(x8) : "memory");
  51 }