linux-kernel - [tip:x86/asm] x86/entry/64: Shrink paranoid_exit

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Date:   Thu, 2 Nov 2017 03:50:42 -0700
From:   tip-bot for Andy Lutomirski <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     peterz@...radead.org, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, dave.hansen@...el.com, hpa@...or.com,
        bpetkov@...e.de, brgerst@...il.com, luto@...nel.org,
        torvalds@...ux-foundation.org, mingo@...nel.org
Subject: [tip:x86/asm] x86/entry/64: Shrink paranoid_exit_restore and make
 labels local

Commit-ID:  e53178328c9b96fbdbc719e78c93b5687ee007c3
Gitweb:     https://git.kernel.org/tip/e53178328c9b96fbdbc719e78c93b5687ee007c3
Author:     Andy Lutomirski <luto@...nel.org>
AuthorDate: Thu, 2 Nov 2017 00:59:02 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 2 Nov 2017 11:04:39 +0100

x86/entry/64: Shrink paranoid_exit_restore and make labels local

paranoid_exit_restore was a copy of restore_regs_and_return_to_kernel.
Merge them and make the paranoid_exit internal labels local.

Keeping .Lparanoid_exit makes the code a bit shorter because it
allows a 2-byte jnz instead of a 5-byte jnz.

Saves 96 bytes of text.

( This is still a bit suboptimal in a non-CONFIG_TRACE_IRQFLAGS
  kernel, but fixing that would make the code rather messy. )

Signed-off-by: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bpetkov@...e.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/510d66a1895cda9473c84b1086f0bb974f22de6a.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/entry/entry_64.S | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 925d562..15539644 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1123,17 +1123,14 @@ ENTRY(paranoid_exit)
 	DISABLE_INTERRUPTS(CLBR_ANY)
 	TRACE_IRQS_OFF_DEBUG
 	testl	%ebx, %ebx			/* swapgs needed? */
-	jnz	paranoid_exit_no_swapgs
+	jnz	.Lparanoid_exit_no_swapgs
 	TRACE_IRQS_IRETQ
 	SWAPGS_UNSAFE_STACK
-	jmp	paranoid_exit_restore
-paranoid_exit_no_swapgs:
+	jmp	.Lparanoid_exit_restore
+.Lparanoid_exit_no_swapgs:
 	TRACE_IRQS_IRETQ_DEBUG
-paranoid_exit_restore:
-	RESTORE_EXTRA_REGS
-	RESTORE_C_REGS
-	REMOVE_PT_GPREGS_FROM_STACK 8
-	INTERRUPT_RETURN
+.Lparanoid_exit_restore:
+	jmp restore_regs_and_return_to_kernel
 END(paranoid_exit)
 
 /*