Make kallsyms heuristics stricter so it doesn't get confused on older devices.

[ezdiy]

Fixes "confused" kallsyms on 4.14 / A10.
This needs to be tested that it doesn't break newer kernels.

When kallsyms get "confused", we guess the offset of addresses/offsets wrong, and subsequently produce garbage kallsyms table. This then segfaults in page_init / other patches pointing to wrong (usually too large) address.

Potentially fixes #204, as they're getting segfault also (though it's not clear where).

[bmax121]

This is unreliable; the kernel image doesn't contain runtime addresses.

[ezdiy]

#if 0. This is left in code if heuristic fails, you're supposed to fill in your own just by copy paste, hence runtime addresses - this is deliberate for simplicity. It works because only deltas between em are compared. It's not immediately apparent, but it's what the code below does:

        uint64_t first = uint_unpack(img + pos, elem_size, info->is_be) - ofs[0];
        for (int i = 1; i < NOFS; i++) {
            if ((uint_unpack(img + pos + i * elem_size, elem_size, info->is_be) - ofs[i]) != first) {
                goto gonext;

That is, ofs[0] is used to "rebase".

[Admirepowered]

hard to merge,The code is not universal