From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5D81230DD10; Tue, 18 Aug 2026 14:57:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787065056; cv=none; b=BOQaEBIEr038hZYSZ0RZvN11ZWJ8mYnubQ0H49AnrG3Rkf391xp1VxzsZv4sgLsFeMyj9OWRNnVOX/19SGq26i9vwr48Sq1xRgUCx1XQOzu0KwmRix3ThCenAtWBuyOsmgL7WxYS69ROuL2gv7DW/qYz9vSZB6cM0qG98Q2mdr4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787065056; c=relaxed/simple; bh=2arL0F2ECWlJkjWCpnJulwnrA+LEqqhfJELQ1VivG10=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=aCxV0jUjh9X8Dt/N+uat3MUSH6LwOM5Jkf2KOS9uVdVep9xLeWPOC1ChPuA4v+HGGROm0bCfcRpR7XVLXtZglkjGMBQe6/e4iw9ZjFrtbV4mGuDZDRtPJl5A5iqn8l70+ZVwNTqmoazn3ehaVM8iZT2ayXeU8Pm8P7tVfbpAEX4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kxt0OngW; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kxt0OngW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5ADD1F000E9; Tue, 18 Aug 2026 14:57:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787065055; bh=YdqUqWZUBav86LMF1u57xEiZtN0Sxgbt9YFutSxX3Cc=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=kxt0OngWAsP3DbCNMojC0BR9g/oTHFiUbHdtc5fpCesK9aADGQzTTp2fiuZp3m9pq KOnWjLjNwz/jiQ0Z1s4kKbPKHfZndxtrGekP58WDMeevpTmSwV5gVTPM0sdR7FKwFc kgC3b+Z9h7VP0LIahW0rFWC+UEFOISB1pNOtd912jrpmfLcFCjJ4jHRPSNBkzQXW8i sHFj8z4Ynoe1iENYWd1zurDIToejSourHal1/HfInR1gMic9mqCyLZmBkIM8kJxfbD ot0DiW29RdNgEVPHRpWhh4tdHi1MMmUqw/1dscPlJ1fzXnGkKSQUCB2fUsQOiV6jzN BHoEdRcJNFEZA== From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v1 06/25] unwind_user: Enable archs that define CFA = SP_callsite + offset Reply-To: sashiko-reviews@lists.linux.dev To: "Jens Remus" Cc: "Alexander Gordeev" , "Christian Borntraeger" , linux-trace-kernel@vger.kernel.org, "Heiko Carstens" , "Vasily Gorbik" , linux-s390@vger.kernel.org In-Reply-To: <20260818144954.2320378-7-jremus@linux.ibm.com> References: <20260818144954.2320378-1-jremus@linux.ibm.com> <20260818144954.2320378-7-jremus@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 18 Aug 2026 14:57:34 +0000 Message-Id: <20260818145734.A5ADD1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Most architectures define their CFA as the value of the stack pointer > (SP) at the call site in the previous frame, as suggested by the DWARF > standard. Therefore the SP at call site can be unwound using an > implicitly assumed value offset from CFA rule with an offset of zero: >=20 > .cfi_val_offset , 0 >=20 > As a result the SP at call site computes as follows: >=20 > SP =3D CFA >=20 > Enable unwinding of user space for architectures, such as s390, which > define their CFA as the value of the SP at the call site in the previous > frame with an offset. Do so by enabling architectures to override the > default SP value offset from CFA of zero with an architecture-specific > one: >=20 > .cfi_val_offset , offset >=20 > So that the SP at call site computes as follows: >=20 > SP =3D CFA + offset >=20 > Signed-off-by: Jens Remus Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260818144954.2320= 378-1-jremus@linux.ibm.com?part=3D6