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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2B932C433E0 for ; Sat, 23 May 2020 05:22:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D14CD207F7 for ; Sat, 23 May 2020 05:22:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="He8O+pWt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D14CD207F7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 698548000A; Sat, 23 May 2020 01:22:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6480780007; Sat, 23 May 2020 01:22:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 536E08000A; Sat, 23 May 2020 01:22:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id 3A96A80007 for ; Sat, 23 May 2020 01:22:48 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id ECB7F5DDA for ; Sat, 23 May 2020 05:22:47 +0000 (UTC) X-FDA: 76846839174.15.year67_357d161b46615 X-HE-Tag: year67_357d161b46615 X-Filterd-Recvd-Size: 5443 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf03.hostedemail.com (Postfix) with ESMTP for ; Sat, 23 May 2020 05:22:47 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D9E70207DA; Sat, 23 May 2020 05:22:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590211366; bh=gBj4Gh7gmXQScSACXe/QWawHujvOrqEcCHWYk5EGB6c=; h=Date:From:To:Subject:In-Reply-To:From; b=He8O+pWtwH1QQ0/949GaTJjLhRCzmtT5M3D36PPDQ25eqsqaXna+tw9XeeWglMhhq peMpy1jKRIVlsIzsmPEqdnbOrm/zCwwLnJ9tE3rT09d8V+SZCYC7atTvIWwU8Bxsmf l/uglBiP4pXRUsmJUse20Q9vxA7u2gL6R//V573w= Date: Fri, 22 May 2020 22:22:45 -0700 From: Andrew Morton To: akpm@linux-foundation.org, andriy.shevchenko@intel.com, aryabinin@virtuozzo.com, bot@kernelci.org, bp@alien8.de, brgerst@gmail.com, dja@axtens.net, elver@google.com, hpa@zytor.com, ilie.halip@gmail.com, jesse.brandeburg@intel.com, linux-mm@kvack.org, luc.vanoostenryck@gmail.com, mingo@redhat.com, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, paulmck@kernel.org, peterz@infradead.org, sedat.dilek@gmail.com, tglx@linutronix.de, torvalds@linux-foundation.org, yamada.masahiro@socionext.com Subject: [patch 02/11] x86: bitops: fix build regression Message-ID: <20200523052245.o_gif23zt%akpm@linux-foundation.org> In-Reply-To: <20200522222217.ee14ad7eda7aab1e6697da6c@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Nick Desaulniers Subject: x86: bitops: fix build regression This is easily reproducible via CC=clang+CONFIG_STAGING=y+CONFIG_VT6656=m. It turns out that if your config tickles __builtin_constant_p via differences in choices to inline or not, these statements produce invalid assembly: $ cat foo.c long a(long b, long c) { asm("orb %1, %0" : "+q"(c): "r"(b)); return c; } $ gcc foo.c foo.c: Assembler messages: foo.c:2: Error: `%rax' not allowed with `orb' Use the `%b` "x86 Operand Modifier" to instead force register allocation to select a lower-8-bit GPR operand. The "q" constraint only has meaning on -m32 otherwise is treated as "r". Not all GPRs have low-8-bit aliases for -m32. Link: http://lkml.kernel.org/r/20200508183230.229464-1-ndesaulniers@google.com Link: https://github.com/ClangBuiltLinux/linux/issues/961 Link: https://lore.kernel.org/lkml/20200504193524.GA221287@google.com/ Link: https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#x86Operandmodifiers Fixes: 1651e700664b4 ("x86: Fix bitops.h warning with a moved cast") Signed-off-by: Nick Desaulniers Tested-by: Sedat Dilek Reported-by: kernelci.org bot Suggested-by: Andy Shevchenko Suggested-by: Brian Gerst Suggested-by: H. Peter Anvin Suggested-by: Ilie Halip Reviewed-by: Nathan Chancellor Reviewed-By: Brian Gerst Tested-by: Nathan Chancellor [build, clang-11] Reviewed-by: Jesse Brandeburg Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Marco Elver Cc: "Paul E. McKenney" Cc: Andrey Ryabinin Cc: Luc Van Oostenryck Cc: Masahiro Yamada Cc: Daniel Axtens Cc: "Peter Zijlstra (Intel)" Signed-off-by: Andrew Morton --- arch/x86/include/asm/bitops.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/arch/x86/include/asm/bitops.h~x86-bitops-fix-build-regression +++ a/arch/x86/include/asm/bitops.h @@ -52,9 +52,9 @@ static __always_inline void arch_set_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { - asm volatile(LOCK_PREFIX "orb %1,%0" + asm volatile(LOCK_PREFIX "orb %b1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" (CONST_MASK(nr) & 0xff) + : "iq" (CONST_MASK(nr)) : "memory"); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(bts) " %1,%0" @@ -72,9 +72,9 @@ static __always_inline void arch_clear_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { - asm volatile(LOCK_PREFIX "andb %1,%0" + asm volatile(LOCK_PREFIX "andb %b1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" (CONST_MASK(nr) ^ 0xff)); + : "iq" (~CONST_MASK(nr))); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(btr) " %1,%0" : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); @@ -123,9 +123,9 @@ static __always_inline void arch_change_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { - asm volatile(LOCK_PREFIX "xorb %1,%0" + asm volatile(LOCK_PREFIX "xorb %b1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" ((u8)CONST_MASK(nr))); + : "iq" (CONST_MASK(nr))); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(btc) " %1,%0" : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); _