main.m

- (IBAction)runTest:(id)sender {
    
    // 32-bit assembly.  Set your architecture to armv7 (not arm64)
    uint32_t code[] = {
        0xe2800001, // add	r0, r0, #1
        0xe12fff1e, // bx	lr
    };
    
    uint32_t *p;
    
    int length = (int32_t)round_page(1024);
    
    vm_address_t bufferAddress;
    kern_return_t result = vm_allocate(mach_task_self(), &bufferAddress, length, VM_FLAGS_ANYWHERE);
    
    if ( result != ERR_SUCCESS ) {
        NSLog(@"Couldn't allocate");
        return;
    }
    
    p = (uint32_t *)bufferAddress;
    
    // copy instructions to function
    p[0] = code[0];
    p[1] = code[1];
    
    /* Mark the buffer read / execute. */
    if (mprotect(p, 1024, PROT_READ | PROT_EXEC)) {
        NSLog(@"Couldn't mprotect");
        return;
    }

    _inc = (inc_t)p;
    int a = 1;
    a = _inc(a);
    
    if (a==2) {
        UIAlertController* alert = [UIAlertController alertControllerWithTitle:@"PROT_EXEC Test"
                                                                       message:@"Test Passed"
                                                                preferredStyle:UIAlertControllerStyleAlert];
        
        UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault
                                                              handler:^(UIAlertAction * action) {}];
        [alert addAction:defaultAction];
        [self presentViewController:alert animated:YES completion:nil];
    }
}