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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1B8B7CCF9EA for ; Mon, 27 Oct 2025 08:44:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Date:MIME-Version:References:Subject:Cc :To:From:Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: List-Owner; bh=LP/xXGwo4LFbZfE0GTaYGZs/mLxKqdf4i1u3clg5O0Q=; b=iry/U2Ko03ZzqV 5gYd7oVPgWrgKQRn6J3ACRMfqP5xFosoNXI4hHLVhleqjEwgyMsO7xC+YfvZURe9UerXVONKn3kxx hnc46aqAjazzaU+33LqsWBm9VoRWMRtur7P/iC4U8JvPdNKNCrpe33MfhiafQwnWXiIHdYvuqZIGt k9R5xevJ3m0hRlpMsEzCEi90mKl+HV0XGrDrmNQzGoGsLe4fu7+EPn/6ZMcpJFBpFDB34+YJvTQNT g5qIIsAD5lHqfFRAORpQVl8zvvmevelQ4FmiajfDgQ+OPxCLjMH7SGVB/gd8Sj7jj3u9mmEM8kHJ5 mZAnKyvxR15dEsjPgZiQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vDIpX-0000000DO4m-43Kt; Mon, 27 Oct 2025 08:43:55 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vDIpP-0000000DNuO-1leR; Mon, 27 Oct 2025 08:43:48 +0000 Message-ID: <20251027083745.168468637@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1761554623; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=fZFzuFe1kZwWOtUDwXLfQwu5MJAw6qMRRDC36ZwVfYw=; b=iFqtRUO/UF2NLRN/kVvPD3nQK4TtwRE+uDnO/hAO9U0W3NxlSPxD/v9M3GkAgfLhzRq8vt CCj5rekchm56nj5Mkf0unik0Wc1yln3p29i6fLF4pDN2PJ4nydOyxBIJ7aCWP4ANtZSG2m EjPshhXBnv1o0WyIzzi7xVc6doO/sprXROIpHSbWiTpe3hvvz1UIyNOTUbrLwKuI0+Coh9 kRGd2RAdEdrM7wGIoDnrf7H33CaumUKoK1SI1UJVHhvofEUCgYuVGouzrKyUl6KLHmEkfh zO6cBR1DBJ/kbO/dGTiHnJ+qTvaCmUiblx012RiwgwaWPfEfF3sWe7Txt2k2tg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1761554623; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=fZFzuFe1kZwWOtUDwXLfQwu5MJAw6qMRRDC36ZwVfYw=; b=5XK95FhES5auvsDsX3IerBIddRz/phA3Vz8BHEXdqt/pEUw83Sq0/r1f7Qo4op0y1URgn/ liQFWLDPUinvqECg== From: Thomas Gleixner To: LKML Cc: kernel test robot , Russell King , linux-arm-kernel@lists.infradead.org, Linus Torvalds , x86@kernel.org, Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , linuxppc-dev@lists.ozlabs.org, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Heiko Carstens , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org, Mathieu Desnoyers , Andrew Cooper , David Laight , Julia Lawall , Nicolas Palix , Peter Zijlstra , Darren Hart , Davidlohr Bueso , =?UTF-8?q?Andr=C3=A9=20Almeida?= , Alexander Viro , Christian Brauner , Jan Kara , linux-fsdevel@vger.kernel.org Subject: [patch V5 01/12] ARM: uaccess: Implement missing __get_user_asm_dword() References: <20251027083700.573016505@linutronix.de> MIME-Version: 1.0 Date: Mon, 27 Oct 2025 09:43:42 +0100 (CET) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251027_014347_606162_D0E71C84 X-CRM114-Status: GOOD ( 14.19 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org When CONFIG_CPU_SPECTRE=n then get_user() is missing the 8 byte ASM variant for no real good reason. This prevents using get_user(u64) in generic code. Implement it as a sequence of two 4-byte reads with LE/BE awareness and make the unsigned long (or long long) type for the intermediate variable to read into dependend on the the target type. The __long_type() macro and idea was lifted from PowerPC. Thanks to Christophe for pointing it out. Reported-by: kernel test robot Signed-off-by: Thomas Gleixner Cc: Russell King Cc: linux-arm-kernel@lists.infradead.org Closes: https://lore.kernel.org/oe-kbuild-all/202509120155.pFgwfeUD-lkp@intel.com/ --- V2a: Solve the *ptr issue vs. unsigned long long - Russell/Christophe V2: New patch to fix the 0-day fallout --- arch/arm/include/asm/uaccess.h | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -283,10 +283,17 @@ extern int __put_user_8(void *, unsigned __gu_err; \ }) +/* + * This is a type: either unsigned long, if the argument fits into + * that type, or otherwise unsigned long long. + */ +#define __long_type(x) \ + __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) + #define __get_user_err(x, ptr, err, __t) \ do { \ unsigned long __gu_addr = (unsigned long)(ptr); \ - unsigned long __gu_val; \ + __long_type(x) __gu_val; \ unsigned int __ua_flags; \ __chk_user_ptr(ptr); \ might_fault(); \ @@ -295,6 +302,7 @@ do { \ case 1: __get_user_asm_byte(__gu_val, __gu_addr, err, __t); break; \ case 2: __get_user_asm_half(__gu_val, __gu_addr, err, __t); break; \ case 4: __get_user_asm_word(__gu_val, __gu_addr, err, __t); break; \ + case 8: __get_user_asm_dword(__gu_val, __gu_addr, err, __t); break; \ default: (__gu_val) = __get_user_bad(); \ } \ uaccess_restore(__ua_flags); \ @@ -353,6 +361,22 @@ do { \ #define __get_user_asm_word(x, addr, err, __t) \ __get_user_asm(x, addr, err, "ldr" __t) +#ifdef __ARMEB__ +#define __WORD0_OFFS 4 +#define __WORD1_OFFS 0 +#else +#define __WORD0_OFFS 0 +#define __WORD1_OFFS 4 +#endif + +#define __get_user_asm_dword(x, addr, err, __t) \ + ({ \ + unsigned long __w0, __w1; \ + __get_user_asm(__w0, addr + __WORD0_OFFS, err, "ldr" __t); \ + __get_user_asm(__w1, addr + __WORD1_OFFS, err, "ldr" __t); \ + (x) = ((u64)__w1 << 32) | (u64) __w0; \ +}) + #define __put_user_switch(x, ptr, __err, __fn) \ do { \ const __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \ _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv