Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751750AbdHBXNP (ORCPT ); Wed, 2 Aug 2017 19:13:15 -0400 Received: from mail-qt0-f177.google.com ([209.85.216.177]:35629 "EHLO mail-qt0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751073AbdHBXNN (ORCPT ); Wed, 2 Aug 2017 19:13:13 -0400 MIME-Version: 1.0 In-Reply-To: <20170802225159.159536-2-mka@chromium.org> References: <20170802225159.159536-1-mka@chromium.org> <20170802225159.159536-2-mka@chromium.org> From: Nick Desaulniers Date: Wed, 2 Aug 2017 16:13:12 -0700 Message-ID: Subject: Re: [PATCH 2/2] arm64: Define PAGE_OFFSET using GENMASK_ULL To: Matthias Kaehlcke Cc: zijun_hu , Andrew Morton , Catalin Marinas , Will Deacon , Mark Rutland , Laura Abbott , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Doug Anderson , Greg Hackmann 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: 2255 Lines: 59 don't forget to include linux/bitops.h now in memory.h /usr/local/google/home/ndesaulniers/android/kernel-wahoo/private/msm-google/arch/arm64/kernel/head.S:47:8: error: function-like macro 'GENMASK_ULL' is not defined #elif (PAGE_OFFSET & 0x1fffff) != 0 ^ /usr/local/google/home/ndesaulniers/android/kernel-wahoo/private/msm-google/arch/arm64/include/asm/memory.h:52:22: note: expanded from macro 'PAGE_OFFSET' #define PAGE_OFFSET GENMASK_ULL(BITS_PER_LONG_LONG - 1, VA_BITS - 1) ^ 1 error generated. On Wed, Aug 2, 2017 at 3:51 PM, Matthias Kaehlcke wrote: > As is the definition causes an integer overflow, which is expected, > however clang raises the following warning: > > arch/arm64/kernel/head.S:47:8: warning: > integer overflow in preprocessor expression > #elif (PAGE_OFFSET & 0x1fffff) != 0 > ^~~~~~~~~~~ > arch/arm64/include/asm/memory.h:52:46: note: > expanded from macro 'PAGE_OFFSET' > #define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1)) > ~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~ > > Use GENMASK_ULL() instead of shifting explicitly, the macro takes care > of avoiding the overflow. > > Reported-by: Nick Desaulniers > Signed-off-by: Matthias Kaehlcke > --- > arch/arm64/include/asm/memory.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 32f82723338a..732d4eed8edd 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -65,7 +65,7 @@ > */ > #define VA_BITS (CONFIG_ARM64_VA_BITS) > #define VA_START (UL(0xffffffffffffffff) << VA_BITS) > -#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1)) > +#define PAGE_OFFSET GENMASK_ULL(BITS_PER_LONG_LONG - 1, VA_BITS - 1) > #define KIMAGE_VADDR (MODULES_END) > #define MODULES_END (MODULES_VADDR + MODULES_VSIZE) > #define MODULES_VADDR (VA_START + KASAN_SHADOW_SIZE) > -- > 2.14.0.rc1.383.gd1ce394fe2-goog > -- Thanks, ~Nick Desaulniers