On Tue, Nov 05, 2024 at 02:33:59PM +0100, Jiri Olsa wrote:

Adding interface to add special mapping for user space page that will be
used as place holder for uprobe trampoline in following changes.

The get_tramp_area(vaddr) function either finds 'callable' page or create
new one.  The 'callable' means it's reachable by call instruction (from
vaddr argument) and is decided by each arch via new arch_uprobe_is_callable
function.

The put_tramp_area function either drops refcount or destroys the special
mapping and all the maps are clean up when the process goes down.

In another thread somewhere, Andrii mentioned that Meta has executables
with more than 4G of .text. This isn't going to work for them, is it?