From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752702AbdJ0UHQ (ORCPT ); Fri, 27 Oct 2017 16:07:16 -0400 Received: from mx2.suse.de ([195.135.220.15]:55943 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751633AbdJ0UHN (ORCPT ); Fri, 27 Oct 2017 16:07:13 -0400 Date: Fri, 27 Oct 2017 22:07:15 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: X86 ML , "linux-kernel@vger.kernel.org" , Brian Gerst , Dave Hansen , Linus Torvalds Subject: Re: [PATCH 05/18] x86/asm/64: Shrink paranoid_exit_restore and make labels local Message-ID: <20171027200715.GB12039@nazgul.tnic> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 26, 2017 at 01:26:37AM -0700, Andy Lutomirski wrote: > 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 > --- > 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 4ad40067162a..d6404a613df4 100644 > --- a/arch/x86/entry/entry_64.S > +++ b/arch/x86/entry/entry_64.S > @@ -1119,17 +1119,14 @@ 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 Kill that paranoid_exit_restore too and save everybody a jump: diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 1b9e8079ca3a..b88e17e120fa 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1122,10 +1122,9 @@ ENTRY(paranoid_exit) jnz .Lparanoid_exit_no_swapgs TRACE_IRQS_IRETQ SWAPGS_UNSAFE_STACK - jmp .Lparanoid_exit_restore + jmp restore_regs_and_return_to_kernel .Lparanoid_exit_no_swapgs: TRACE_IRQS_IRETQ_DEBUG -.Lparanoid_exit_restore: jmp restore_regs_and_return_to_kernel END(paranoid_exit) -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --