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[46.204.108.203]) by smtp.gmail.com with ESMTPSA id f10-20020a2ea0ca000000b00295b9db4302sm1247856ljm.33.2023.03.01.00.58.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Mar 2023 00:58:46 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 476312c6-b80f-11ed-969f-2f268f93b82a DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1677661127; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=6uT3qU1x60f3c7F7wVSes6L/icFBJH8FmXsYloSy1AE=; b=qRj4iJRkF+K0uo+72q09/mTARiBeNR969MH3zpBOzwgtsJsPyGUG8ae/Fh+5ZMRA+V 7k1RQUyPU3S0SzcjIXFJOfIr9sQtx6uwSmIzaRnJsqH78DwYby4NVia2npz3SbjQKfor AeIRFMgQbSSqN9K3ofcsqS6RcQDQCMvr+gfGdTcQwxMYbG3s59LGs92q7HUX3QK3FZQR z36vwtC5rBkHb5CU765pi5TSmFzBsP8UnirLBaHXPdRB45w0/ZcuytfQok8ikUj4QftJ A8Fv4uL7lTiZ/kIBJaUz6vCjzL3l7aHxO1ozP3/RPfwFo0iRy+oIm2ii+4uoizZNmEYJ UCag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677661127; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=6uT3qU1x60f3c7F7wVSes6L/icFBJH8FmXsYloSy1AE=; b=yeADI/fCZHRe4n2Bsb56AIoaVxqiNQ5Ho0G4iLsSFSxgr/JC6F3iu8E87qbZ+iDVCc 3cL9i1lW+/kd/ktATSKCQE6SvEbutTDx1QMYHHqFGwS1kIcUbC8SwYPHCm7hrQNWu38l skYN24nxLOHz802OVBKNjAnNk1wPCOjGdlhYTG9q/Wue9wsvCKSzMPJva0b4EVdWQA1a j4nrktHroptGmiW009pfr+KHVNCkK4EwOgKYMSR0dfUhULpe0I7iKgzKS4I1AJ0wEvfI GWirKEPAvBh3qhbquxLbKmxrdPzyUXbUEmIW2MWCtfWBXVxeVa6Gmnwqze4o3an3EeFm ZxHw== X-Gm-Message-State: AO0yUKVTppWmsDzcxib3zgXg9Glj4ZhkmPDeCP0whw20Fc9ctbB0tvHv TWR37YWvkhNNGCTpRGmpVHE= X-Google-Smtp-Source: AK7set+WNWSu2Hrku/f4CuyLaI9SQ5GeoQxiAMWapW/Oj8meQN9+kahHVvXtbeIawxzo+9kOvQx4wA== X-Received: by 2002:a05:651c:331:b0:295:903b:6a8a with SMTP id b17-20020a05651c033100b00295903b6a8amr1614481ljp.48.1677661126985; Wed, 01 Mar 2023 00:58:46 -0800 (PST) Message-ID: Subject: Re: [PATCH v3 3/4] xen/arm: switch ARM to use generic implementation of bug.h From: Oleksii To: Julien Grall , xen-devel@lists.xenproject.org Cc: Jan Beulich , Andrew Cooper , Stefano Stabellini , Gianluca Guida , Bertrand Marquis , Volodymyr Babchuk Date: Wed, 01 Mar 2023 10:58:15 +0200 In-Reply-To: <46e96dd9-bcb4-4569-b282-05c019cabcc3@xen.org> References: <46e96dd9-bcb4-4569-b282-05c019cabcc3@xen.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.3 (3.46.3-1.fc37) MIME-Version: 1.0 On Tue, 2023-02-28 at 17:48 +0000, Julien Grall wrote: > Hi Oleksii, >=20 > On 28/02/2023 15:09, Oleksii wrote: > > On Sat, 2023-02-25 at 16:49 +0000, Julien Grall wrote: > > > Hi Oleksii, > > >=20 > > > On 24/02/2023 11:31, Oleksii Kurochko wrote: > > > > The following changes were made: > > > > * make GENERIC_BUG_FRAME mandatory for ARM > > >=20 > > > I have asked in patch #1 but will ask it again because I think > > > this > > > should be recorded in the commit message. Can you outline why it > > > is > > > not > > > possible to completely switch to the generic version? > > I haven't tried to switch ARM too because of comment regarding 'i' > > in > > : > > /* > > =C2=A0 * GCC will not allow to use "i"=C2=A0 when PIE is enabled (Xen d= oesn't > > set > > the > > =C2=A0 * flag but instead rely on the default value from the compiler). > > So > > the > > =C2=A0 * easiest way to implement run_in_exception_handler() is to pass > > the > > to > > =C2=A0 * be called function in a fixed register. > > =C2=A0 */ >=20 > I would expect this comment to be valid for any arch. So if there is > a=20 > need to deal with PIE, then we would not be able to use "i" in the > BUG=20 > frame. >=20 > Note that we are now explicitly compiling Xen without PIE (see > Config.mk). Then it looks like some architectures isn't expected to be compiled with PIE. I mean that x86's bug.h is used 'i' and there is no any alternative version in case of PIE. If Xen should be compilable with PIE then we have to use ARM implementation of bug.h everywhere. ( based on comment about 'i' with PIE ). Now I am totally confused... ~ Oleksii