From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id F2822B7416 for ; Wed, 16 Mar 2011 02:07:24 +1100 (EST) Subject: Re: [PATCH] e500: Erratum cpu a005 workaround Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: text/plain; charset=us-ascii From: Kumar Gala In-Reply-To: <1295935333-13045-1-git-send-email-yu.liu@freescale.com> Date: Tue, 15 Mar 2011 10:07:18 -0500 Message-Id: <518DEEA6-64ED-441C-B795-BCAC9913CDB4@kernel.crashing.org> References: <1295935333-13045-1-git-send-email-yu.liu@freescale.com> To: Liu Yu Cc: B11780@freescale.com, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Jan 25, 2011, at 12:02 AM, Liu Yu wrote: > This errata can occur if a single-precision floating-point, = double-precision > floating-point or vector floating-point instruction on a mispredicted = branch > path signals one of the floating-point data interrupts which are = enabled by the > SPEFSCR (FINVE, FDBZE, FUNFE or FOVFE bits). This interrupt must be = recorded > in a one-cycle window when the misprediction is resolved. If this = extremely > rare event should occur, the result could be: >=20 > The SPE Data Exception from the mispredicted path may be reported > erroneously if a single-precision floating-point, double-precision > floating-point or vector floating-point instruction is the second = instruction > on the correct branch path. >=20 > According to errata description, some efp instructions > which are not supposed to trigger SPE exceptions > can trigger the exceptions in this case. > However, as we haven't emulated these instructions here, > a signal will send to userspace, and userspace application would exit. >=20 > This patch re-issue the efp instruction that we haven't emulated, > so that hardware can properly execute it again if this case happen. >=20 > Signed-off-by: Liu Yu > --- > This is an erratum workaround patch. > It would be better if the patch can go into 2.6.38. >=20 > arch/powerpc/include/asm/reg.h | 2 + > arch/powerpc/math-emu/math_efp.c | 53 = +++++++++++++++++++++++++++++++++++++- > 2 files changed, 54 insertions(+), 1 deletions(-) applied - k=