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
