Rust doesn’t have “safe” and “unsafe” modes in the sense your comment alludes to.

You can just do the little unsafe thing in a function that guarantees its safety, and then the rest of the code is safe.

For example, using C functions from rust is unsafe, but most of the time a simple wrapper can be made safe.

Example C function:

int arraysum(const int *array, int length) {
    int sum = 0;
    while (length > 0) {
        sum += *array;
        array++;
        length--;
   }
}

In rust, you can call that function safely by just wrapping it with a function that makes sure that length is always the size of array. Such as:

fn rust_arraysum(array: Vec<i32>) -> i32 {
    unsafe{ arraysum(array.as_ptr(), array.len() as i32)}
}

Even though unsafe is used, it is perfectly safe to do so. And now we can call rust_arraysum without entering “unsafe mode”

You could do similar wrappers if you want to write your embedded code. Where only a fraction of the code is potentially unsafe.

And even in unsafe blocks, you don’t disable all of the rust checks.