The PUSH_AND_CLEAR_REGS macro is able to insert the GP registers "above" the original return address. This allows us to move a sizeable part of the interrupt entry macro to an interrupt entry helper function:
text data bss dec hex filename 20987 0 0 20987 51fb entry_64.o-orig 17905 0 0 17905 45f1 entry_64.o Suggested-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Dominik Brodowski <li...@dominikbrodowski.net> --- arch/x86/entry/entry_64.S | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 5d9cb0f037e4..de8a0da0d347 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -526,6 +526,15 @@ END(irq_entries_start) * * Entry runs with interrupts off. */ +ENTRY(interrupt_helper) + UNWIND_HINT_FUNC + cld + + PUSH_AND_CLEAR_REGS save_ret=1 + ENCODE_FRAME_POINTER 8 + + ret +END(interrupt_helper) /* 0(%rsp): ~(interrupt number) */ .macro interrupt func @@ -537,8 +546,7 @@ END(irq_entries_start) call switch_to_thread_stack 1: - PUSH_AND_CLEAR_REGS - ENCODE_FRAME_POINTER + call interrupt_helper testb $3, CS(%rsp) jz 1f -- 2.16.1