kcov: properly handle subsequent mmap calls

Allocate the kcov buffer during KCOV_MODE_INIT in order to untie mmapping
of a kcov instance and the actual coverage collection process. Modify
kcov_mmap, so that it can be reliably used any number of times once
KCOV_MODE_INIT has succeeded.

These changes to the user-facing interface of the tool only weaken the
preconditions, so all existing user space code should remain compatible
with the new version.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Aleksandr Nogikh <[email protected]>
Reviewed-by: Dmitry Vyukov <[email protected]>
Reviewed-by: Andrey Konovalov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Taras Madan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions