Test for checking whether PAC is enabled, or is a NOP on the current system.

pactest.cpp

#include <cstdio>
#include <cstdint>

__attribute__((noinline))
int pac_test()
{
    uint64_t original = 0;
    uint64_t res = 0;
    printf("I wonder if this has PAC enabled?\n");
    __asm__ ("MOV %[original], X30\n"
             "PACIASP\n"
             "MOV %[result], X30\n"
    : [result] "=r" (res), [original] "=r" (original)
    );

    printf("Original LR (X30): %ld\nNew LR (X30): %ld\n", original, res);
    return original != res;
}

int main()
{
    if (pac_test())
        printf("PAC is enabled! (PACIASP)\n");
    else
        printf("PAC is not enabled (NOP).\n");
        
    return 0;
}