Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752407AbbGBPd4 (ORCPT ); Thu, 2 Jul 2015 11:33:56 -0400 Received: from mail-la0-f50.google.com ([209.85.215.50]:36272 "EHLO mail-la0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752467AbbGBPdu (ORCPT ); Thu, 2 Jul 2015 11:33:50 -0400 MIME-Version: 1.0 In-Reply-To: <20150702105258.GG4001@pd.tnic> References: <1d672626fd72cb5fd5814f589d3147b1c15a1647.1435602481.git.luto@kernel.org> <20150702105258.GG4001@pd.tnic> From: Andy Lutomirski Date: Thu, 2 Jul 2015 08:33:28 -0700 Message-ID: Subject: Re: [PATCH v4 12/17] x86/asm/entry/64: Save all regs on interrupt entry To: Borislav Petkov Cc: Andy Lutomirski , X86 ML , "linux-kernel@vger.kernel.org" , =?UTF-8?B?RnLDqWTDqXJpYyBXZWlzYmVja2Vy?= , Rik van Riel , Oleg Nesterov , Denys Vlasenko , Kees Cook , Brian Gerst , Paul McKenney Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2005 Lines: 58 On Thu, Jul 2, 2015 at 3:52 AM, Borislav Petkov wrote: > On Mon, Jun 29, 2015 at 12:33:44PM -0700, Andy Lutomirski wrote: >> To prepare for the big rewrite of the error and interrupt exit >> paths, we will need pt_regs completely filled in. It's already >> completely filled in when error_exit runs, so rearrange interrupt >> handling to match it. This will slow down interrupt handling very >> slightly (eight instructions), but the simplification it enables >> will be more than worth it. >> >> Signed-off-by: Andy Lutomirski >> --- >> arch/x86/entry/entry_64.S | 29 +++++++++-------------------- >> 1 file changed, 9 insertions(+), 20 deletions(-) >> >> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S >> index 9bc76766aa71..51d34fafe4c0 100644 >> --- a/arch/x86/entry/entry_64.S >> +++ b/arch/x86/entry/entry_64.S >> @@ -502,21 +502,13 @@ END(irq_entries_start) >> /* 0(%rsp): ~(interrupt number) */ >> .macro interrupt func >> cld >> - /* >> - * Since nothing in interrupt handling code touches r12...r15 members >> - * of "struct pt_regs", and since interrupts can nest, we can save >> - * four stack slots and simultaneously provide >> - * an unwind-friendly stack layout by saving "truncated" pt_regs >> - * exactly up to rbp slot, without these members. >> - */ >> - ALLOC_PT_GPREGS_ON_STACK -RBP >> - SAVE_C_REGS -RBP >> - /* this goes to 0(%rsp) for unwinder, not for saving the value: */ >> - SAVE_EXTRA_REGS_RBP -RBP > > That macro's unused now AFAICT. > I'll delete it in v5. --Andy > -- > Regards/Gruss, > Boris. > > ECO tip #101: Trim your mails when you reply. > -- -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/