[RFC PATCH 0/4] x86/entry/64: interrupt entry size reduction

From: Dominik Brodowski
Date: Wed Feb 14 2018 - 13:23:06 EST


This patchset applies on top of the two other tip/pti-related patches
I sent out moments ago,[*] and try to implement what Linus suggested a
few days ago[+].

[+] http://lkml.kernel.org/r/20180214175924.23065-1-linux@xxxxxxxxxxxxxxxxxxxx
[*] http://lkml.kernel.org/r/CA+55aFwLTF3EtaQ4OpDv2UM41J=EU7gfemv=eVq+uQi31-usSg@xxxxxxxxxxxxxx .

Overall, these patches provide for a sizeable cutting of up to 4.35k:

text data bss dec hex filename
20987 0 0 20987 51fb entry_64.o-orig
16621 0 0 16621 40ed entry_64.o

They are split up in four small steps to easen the review. Another
advantage is that we can decide whether each additional step is really
worth it in relation to an increase in code complexity.

NOTE / WARNING: As usual, please be extremely stringent in reviewing these
patches.

Thanks,
Dominik

Dominik Brodowski (4):
x86/entry/64: move PUSH_AND_CLEAR_REGS from interrupt macro to helper
function
x86/entry/64: move ENTER_IRQ_STACK from interrupt macro to helper
function
x86/entry/64: move switch_to_thread_stack to interrupt helper function
x86/entry/64: remove interrupt macro

arch/x86/entry/entry_64.S | 99 +++++++++++++++++++++++++++++------------------
1 file changed, 62 insertions(+), 37 deletions(-)

--
2.16.1