Re: [PATCH 00/14] scripts/sorttable: ftrace: Remove place holders for weak functions in available_filter_functions

Linus Torvalds
2025-01-02T19:30:32Z

On Thu, 2 Jan 2025 at 10:59, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Where the file created by "nm -S" is read, recording the address
> and the associated sizes of each function. It then is sorted, and
> before sorting the mcount_loc table, it is scanned to make sure
> all symbols in the mcounc_loc are within the boundaries of the functions
> defined by nm. If they are not, they are zeroed out, as they are most
> likely weak functions (I don't know what else they would be).

Please just do this by sorting non-existent functions at the end,
instead of just zeroing them out.

That makes the mcount_loc table dense in valid entries. We could then
just rewrite the size of the table (or just add a variable containing
the size, if you don't want to change ELF metadata - but you're
already sorting the table, so why not?)

Because:

> Then on boot up, when creating the ftrace tables from the mcount_loc
> table, it will ignore any function that matches the kaslr_offset()
> value.

Why even do that? Why not just make the mcount_loc table be proper in
the first place.

Linus