From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B96B6C352AA for ; Tue, 1 Oct 2019 14:39:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 977002054F for ; Tue, 1 Oct 2019 14:39:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389165AbfJAOjo (ORCPT ); Tue, 1 Oct 2019 10:39:44 -0400 Received: from foss.arm.com ([217.140.110.172]:51216 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388932AbfJAOjn (ORCPT ); Tue, 1 Oct 2019 10:39:43 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BFB4F1000; Tue, 1 Oct 2019 07:39:42 -0700 (PDT) Received: from [10.37.8.149] (unknown [10.37.8.149]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6C8253F71A; Tue, 1 Oct 2019 07:39:41 -0700 (PDT) Subject: Re: [PATCH v3 3/5] arm64: vdso32: Fix compilation warning To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, ard.biesheuvel@linaro.org, ndesaulniers@google.com, catalin.marinas@arm.com, tglx@linutronix.de References: <20190920142738.qlsjwguc6bpnez63@willie-the-truck> <20190926214342.34608-1-vincenzo.frascino@arm.com> <20190926214342.34608-4-vincenzo.frascino@arm.com> <20191001132108.jx2x7quyk2p2vyfw@willie-the-truck> From: Vincenzo Frascino Message-ID: Date: Tue, 1 Oct 2019 15:41:31 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20191001132108.jx2x7quyk2p2vyfw@willie-the-truck> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/1/19 2:21 PM, Will Deacon wrote: > On Thu, Sep 26, 2019 at 10:43:40PM +0100, Vincenzo Frascino wrote: >> As reported by Will Deacon the following compilation warning appears >> during the compilation of the vdso32: >> >> In file included from ./arch/arm64/include/asm/thread_info.h:17:0, >> from ./include/linux/thread_info.h:38, >> from ./arch/arm64/include/asm/preempt.h:5, >> from ./include/linux/preempt.h:78, >> from ./include/linux/spinlock.h:51, >> from ./include/linux/seqlock.h:36, >> from ./include/linux/time.h:6, >> from .../work/linux/lib/vdso/gettimeofday.c:7, >> from :0: >> ./arch/arm64/include/asm/memory.h: In function ‘__tag_set’: >> ./arch/arm64/include/asm/memory.h:233:15: warning: cast from pointer to >> integer of different size [-Wpointer-to-int-cast] >> u64 __addr = (u64)addr & ~__tag_shifted(0xff); >> ^ >> In file included from ./arch/arm64/include/asm/pgtable-hwdef.h:8:0, >> from ./arch/arm64/include/asm/processor.h:34, >> from ./arch/arm64/include/asm/elf.h:118, >> from ./include/linux/elf.h:5, >> from ./include/linux/elfnote.h:62, >> from arch/arm64/kernel/vdso32/note.c:11: >> ./arch/arm64/include/asm/memory.h: In function ‘__tag_set’: >> ./arch/arm64/include/asm/memory.h:233:15: warning: cast from pointer to >> integer of different size [-Wpointer-to-int-cast] >> u64 __addr = (u64)addr & ~__tag_shifted(0xff); >> ^ >> >> This happens because few 64 bit compilation headers are included during >> the generation of vdso32. >> >> Fix the issue redefining the __tag_set function. >> >> Note: This fix is meant to be temporary, a more comprehensive solution >> based on the refactoring of the generic headers will be provided with a >> future patch set. At that point it will be possible to revert this patch. >> >> Cc: Will Deacon >> Cc: Catalin Marinas >> Signed-off-by: Vincenzo Frascino >> --- >> arch/arm64/include/asm/memory.h | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h >> index b61b50bf68b1..c61b2eb50a3b 100644 >> --- a/arch/arm64/include/asm/memory.h >> +++ b/arch/arm64/include/asm/memory.h >> @@ -228,11 +228,14 @@ static inline unsigned long kaslr_offset(void) >> #define __tag_get(addr) 0 >> #endif /* CONFIG_KASAN_SW_TAGS */ >> >> +#ifdef __aarch64__ >> +/* Do not attempt to compile this code with compat vdso */ >> static inline const void *__tag_set(const void *addr, u8 tag) >> { >> u64 __addr = (u64)addr & ~__tag_shifted(0xff); >> return (const void *)(__addr | __tag_shifted(tag)); >> } >> +#endif > > Sorry, but I'm not taking this. > > I know you're trying to fix the issues I reported as quickly as you can (and > thank you for that), but I'm sure that you agree this needs more thought to > develop a proper solution to what is a much bigger issue than can be solved > by sprinkling #ifdefs. I can live with the warning on the basis that a > proper fix is in the pipeline, but in the meantime it can serve as a > reminder that we're not done here. > This was my original preference as well, if we silence the warnings we tend to forget about them. Since you reported the issue as urgent, I reacted with something that fixes it temporarily, but I have not objections if you want to wait for a more comprehensive solution. > Will > -- Regards, Vincenzo