From nobody Sun Feb 8 11:06:18 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A5FF23904D6; Tue, 13 Jan 2026 13:47:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768312053; cv=none; b=WmCRBCg0IOTYdqls6ZelnND2aVyEoyxGa7abxn1qJCoZS/PxGSIkC30r0NlJyoBTepY+wLdKdI/BBJuCaKrRZ3iFKfn9WYxhRwX1LL5uxV+hV0rpg5NhL/+Wpa0IMoU6Zu18wSw7aOqiL+XcXwpKiLhHLk3wE0mOTX1dUZFBmvo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768312053; c=relaxed/simple; bh=weiPnmfHFZ3ElBOLcjP1pFWkvfK+2CYE/K5CPRMhBJQ=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=bMS93EUckO0n4ScqYR7Get6Lm7Y4XFtGg7d6/REDv289Ox9XgC9OjNtGa6Uh9alNeih7KC8fImhR41V3/K5gAri76yX0wSg4MI81CfSNh184kOc/I8GNQqBtbuk34eGiS+ldZEfH3QBiVEOL6ZK2CB1ZSVMzkRTq2OtbBEAq1PM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=x/IpNSgh; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=xevI0Twi; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="x/IpNSgh"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="xevI0Twi" Date: Tue, 13 Jan 2026 13:47:29 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1768312050; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JIVDtZvr60lr512WnCflRnUDaq8FQeIL7Jsjil1txPY=; b=x/IpNSgh785SJeg3IMr6tsDCBSVgCWZyQywXJ1WBmrXtnnZGAg2HbIBau0wpp7lWULIy6e OrsS5HZzNOKqh5O0f7qcCvyN4YbtfyA+uN9uZbcWHxbbjt+V4fu6TQGMuV3vjlwpu4ksmG MI9YzHmhmpdp/HvsBGPlHdg294TPiXTdqqf28VJ6flrOywaesnuOqb7kf+CelKAP7q5RXL pd6OwLLsrv0ris/7qkkgQ+rLgOciFI3IzhmIa71D2zxw8efNH7fems3oTo6j+Jb/DWbg4r jzDhb0ISc1FAifrB8vcMnJwSSViHDj4YMDQriNGXLMKQzaDge6RS2Fa/XRshBw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1768312050; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JIVDtZvr60lr512WnCflRnUDaq8FQeIL7Jsjil1txPY=; b=xevI0TwiinL2Rv0ZrBj1WPzXvelGdcqwGx2iMTJMTzLRVt3Kha8wZuijfGtwnLwgamxBx/ JNJDpnD2rjeXunAA== From: "tip-bot2 for Ian Rogers" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: timers/vdso] vdso: Switch get/put_unaligned() from packed struct to memcpy() Cc: Ian Rogers , Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20251016205126.2882625-3-irogers@google.com> References: <20251016205126.2882625-3-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <176831204906.510.7821433428524791632.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the timers/vdso branch of tip: Commit-ID: e04a494143bab7ea804fe1ebe286701ee8288e4a Gitweb: https://git.kernel.org/tip/e04a494143bab7ea804fe1ebe286701ee= 8288e4a Author: Ian Rogers AuthorDate: Thu, 16 Oct 2025 13:51:24 -07:00 Committer: Thomas Gleixner CommitterDate: Tue, 13 Jan 2026 14:46:00 +01:00 vdso: Switch get/put_unaligned() from packed struct to memcpy() Type punning is necessary for get/put_unaligned() but the use of a packed struct violates strict aliasing rules, requiring -fno-strict-aliasing to be passed to the C compiler. Switch to using memcpy() so that -fno-strict-aliasing isn't necessary. Signed-off-by: Ian Rogers Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20251016205126.2882625-3-irogers@google.com --- include/vdso/unaligned.h | 41 +++++++++++++++++++++++++++++++++------ 1 file changed, 35 insertions(+), 6 deletions(-) diff --git a/include/vdso/unaligned.h b/include/vdso/unaligned.h index ff0c06b..9076483 100644 --- a/include/vdso/unaligned.h +++ b/include/vdso/unaligned.h @@ -2,14 +2,43 @@ #ifndef __VDSO_UNALIGNED_H #define __VDSO_UNALIGNED_H =20 -#define __get_unaligned_t(type, ptr) ({ \ - const struct { type x; } __packed * __get_pptr =3D (typeof(__get_pptr))(p= tr); \ - __get_pptr->x; \ +#include + +/** + * __get_unaligned_t - read an unaligned value from memory. + * @type: the type to load from the pointer. + * @ptr: the pointer to load from. + * + * Use memcpy to affect an unaligned type sized load avoiding undefined be= havior + * from approaches like type punning that require -fno-strict-aliasing in = order + * to be correct. As type may be const, use __unqual_scalar_typeof to map = to a + * non-const type - you can't memcpy into a const type. The + * __get_unaligned_ctrl_type gives __unqual_scalar_typeof its required + * expression rather than type, a pointer is used to avoid warnings about = mixing + * the use of 0 and NULL. The void* cast silences ubsan warnings. + */ +#define __get_unaligned_t(type, ptr) ({ \ + type *__get_unaligned_ctrl_type __always_unused =3D NULL; \ + __unqual_scalar_typeof(*__get_unaligned_ctrl_type) __get_unaligned_val; \ + __builtin_memcpy(&__get_unaligned_val, (void *)(ptr), \ + sizeof(__get_unaligned_val)); \ + __get_unaligned_val; \ }) =20 -#define __put_unaligned_t(type, val, ptr) do { \ - struct { type x; } __packed * __put_pptr =3D (typeof(__put_pptr))(ptr); \ - __put_pptr->x =3D (val); \ +/** + * __put_unaligned_t - write an unaligned value to memory. + * @type: the type of the value to store. + * @val: the value to store. + * @ptr: the pointer to store to. + * + * Use memcpy to affect an unaligned type sized store avoiding undefined + * behavior from approaches like type punning that require -fno-strict-ali= asing + * in order to be correct. The void* cast silences ubsan warnings. + */ +#define __put_unaligned_t(type, val, ptr) do { \ + type __put_unaligned_val =3D (val); \ + __builtin_memcpy((void *)(ptr), &__put_unaligned_val, \ + sizeof(__put_unaligned_val)); \ } while (0) =20 #endif /* __VDSO_UNALIGNED_H */