linux-kernel - [RFC PATCH v3 5/6] x86/entry/64: move ASM_CLAC to interrupt

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Message-Id: <20180220210113.6725-6-linux@dominikbrodowski.net>
Date:   Tue, 20 Feb 2018 22:01:12 +0100
From:   Dominik Brodowski <linux@...inikbrodowski.net>
To:     linux-kernel@...r.kernel.org, mingo@...nel.org, x86@...nel.org,
        brgerst@...il.com, luto@...nel.org, jpoimboe@...hat.com
Cc:     torvalds@...ux-foundation.org, ak@...ux.intel.com,
        tglx@...utronix.de, dan.j.williams@...el.com
Subject: [RFC PATCH v3 5/6] x86/entry/64: move ASM_CLAC to interrupt_entry

Moving ASM_CLAC to interrupt_entry means two instructions (addq / pushq
and call interrupt_entry) are not covered by it. However, it offers a
noticeable size reduction (-.2k):

   text	   data	    bss	    dec	    hex	filename
  16882	      0	      0	  16882	   41f2	entry_64.o-orig
  16623	      0	      0	  16623	   40ef	entry_64.o

Suggested-by: Brian Gerst <brgerst@...il.com>
Signed-off-by: Dominik Brodowski <linux@...inikbrodowski.net>
---
 arch/x86/entry/entry_64.S | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 8ea03cf94a2d..42a4b652469d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -572,6 +572,7 @@ END(irq_entries_start)
 /* 8(%rsp): ~(interrupt number) */
 ENTRY(interrupt_entry)
 	UNWIND_HINT_FUNC
+	ASM_CLAC
 	cld
 
 	testb	$3, CS-ORIG_RAX+8(%rsp)
@@ -614,7 +615,6 @@ END(interrupt_entry)
 	 */
 	.p2align CONFIG_X86_L1_CACHE_SHIFT
 common_interrupt:
-	ASM_CLAC
 	addq	$-0x80, (%rsp)			/* Adjust vector to [-256, -1] range */
 	call	interrupt_entry
 	UNWIND_HINT_REGS indirect=1
@@ -811,7 +811,6 @@ END(common_interrupt)
 .macro apicinterrupt3 num sym do_sym
 ENTRY(\sym)
 	UNWIND_HINT_IRET_REGS
-	ASM_CLAC
 	pushq	$~(\num)
 .Lcommon_\sym:
 	call	interrupt_entry
-- 
2.16.2