From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756475AbbEVAdG (ORCPT ); Thu, 21 May 2015 20:33:06 -0400 Received: from terminus.zytor.com ([198.137.202.10]:54387 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756350AbbEVAdD (ORCPT ); Thu, 21 May 2015 20:33:03 -0400 Message-ID: <555E791D.1000700@zytor.com> Date: Thu, 21 May 2015 17:32:29 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Andy Lutomirski , x86@kernel.org, "H.J. Lu" CC: Borislav Petkov , Jan Beulich , Binutils , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: Stop relying on magic jmp behavior for early_idt_handlers References: <5bf75d3abce25ec615048075705f120b331aaf0b.1432253793.git.luto@kernel.org> In-Reply-To: <5bf75d3abce25ec615048075705f120b331aaf0b.1432253793.git.luto@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/21/2015 05:17 PM, Andy Lutomirski wrote: > > diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h > index 5a9856eb12ba..4bbe0eb24d7e 100644 > --- a/arch/x86/include/asm/segment.h > +++ b/arch/x86/include/asm/segment.h > @@ -231,12 +231,21 @@ > #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8) > > #ifdef __KERNEL__ > -#ifndef __ASSEMBLY__ > > -extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5]; > +/* > + * early_idt_handlers is an array of entry points. For simplicity, it's > + * a real array. We allocate nine bytes for each entry: two one-byte > + * push instructions and a five-byte jump in the worst case. > + */ > +#define EARLY_IDT_HANDLER_STRIDE 9 > +#ifndef __ASSEMBLY__ > +extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][EARLY_IDT_HANDLER_STRIDE]; > #ifdef CONFIG_TRACING > # define trace_early_idt_handlers early_idt_handlers > #endif > +#endif > + > +#ifndef __ASSEMBLY__ > Please get rid of the unnecessary #ifndef/#endif pair. > +/* Build the early_idt_handlers array */ > __INIT > .globl early_idt_handlers Let's use ENTRY(early_idt_handlers) for consistency. Otherwise it looks good. I like the use of .fill better than moving ., it seems more robust to me. Conditionally-Acked-by: H. Peter Anvin