samples: ftrace: Save required argument registers in sample trampolines

The ftrace-direct-too sample traces the handle_mm_fault function whose
signature changed since the introduction of the sample. Since:
commit bce617edecad ("mm: do page fault accounting in handle_mm_fault")
handle_mm_fault now has 4 arguments. Therefore, the sample trampoline
should save 4 argument registers.

s390 saves all argument registers already so it does not need a change
but x86_64 needs an extra push and pop.

This also evolves the signature of the tracing function to make it
mirror the signature of the traced function.

Link: https://lkml.kernel.org/r/[email protected]

Cc: [email protected]
Fixes: bce617edecad ("mm: do page fault accounting in handle_mm_fault")
Reviewed-by: Steven Rostedt (Google) <[email protected]>
Reviewed-by: Mark Rutland <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Florent Revest <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

0 files changed, 0 insertions, 0 deletions