From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM01-BN3-obe.outbound.protection.outlook.com (mail-bn3nam01on0070.outbound.protection.outlook.com [104.47.33.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vXJ336XmqzDq8M for ; Tue, 28 Feb 2017 10:34:55 +1100 (AEDT) Subject: Re: [PATCH] jump_label: align jump_entry table to at least 4-bytes To: Jason Baron , Steven Rostedt , Sachin Sant References: <1488221364-13905-1-git-send-email-jbaron@akamai.com> <93219edf-0f6d-5cc7-309c-c998f16fe7ac@akamai.com> <20170227160601.5b79a1fe@gandalf.local.home> <6db89a8d-6053-51d1-5fd4-bae0179a5ebd@caviumnetworks.com> <20170227170911.2280ca3e@gandalf.local.home> <7fa95eea-20be-611c-2b63-fca600779465@caviumnetworks.com> <20170227173630.57fff459@gandalf.local.home> <7bd72716-feea-073f-741c-04212ebd0802@caviumnetworks.com> <68fe24ea-7795-24d8-211b-9d8a50affe9f@akamai.com> Cc: linux-mips@linux-mips.org, Ralf Baechle , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Ingo Molnar , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Anton Blanchard , Rabin Vincent , Russell King , Chris Metcalf , Zhigang Lu From: David Daney Message-ID: <8fb467e8-2ab9-e52b-ea47-083947b9cfe4@caviumnetworks.com> Date: Mon, 27 Feb 2017 15:34:44 -0800 MIME-Version: 1.0 In-Reply-To: <68fe24ea-7795-24d8-211b-9d8a50affe9f@akamai.com> Content-Type: text/plain; charset=windows-1252; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 02/27/2017 02:50 PM, Jason Baron wrote: > > > On 02/27/2017 05:45 PM, David Daney wrote: >> On 02/27/2017 02:36 PM, Steven Rostedt wrote: >>> On Mon, 27 Feb 2017 14:21:21 -0800 >>> David Daney wrote: >>> >>>> See attached for mips. It seems to do the right thing. >>>> >>>> I leave it as an exercise to the reader to fix the other architectures. >>>> >>>> Consult your own binutils experts to verify that what I say is true. >>> >>> It may still just be safer to do the pointers instead. That way we >>> don't need to worry about some strange arch or off by one binutils >>> messing it up. >> >> Obviously it is your choice, but this is bog standard ELF linking. In >> theory even the arrays of power-of-2 sized objects should also supply an >> entity size. Think __ex_table and its ilk. >> >> >> The benefit of supplying an entsize is that you don't have to change the >> structure of the existing code and risk breaking something in the >> process. >> >> David Daney >> >> > > Thanks for the suggestion! I would like to see if this resolves the ppc > issue we had. I'm attaching a powerpc patch based on your suggestion. > Hopefully, Sachin can try it. > If there are problems, you could try something like: $ find . -name \*\.o | xargs mips64-octeon-linux-gnu-readelf -eW | grep 'File:\| __jump_table' File: ./drivers/firmware/built-in.o File: ./drivers/built-in.o [3249] __jump_table PROGBITS 0000000000000000 1838c8 0022c8 18 WAM 0 0 8 File: ./drivers/spi/built-in.o [82] __jump_table PROGBITS 0000000000000000 008cb0 000048 18 WAM 0 0 8 File: ./drivers/spi/spi-cavium-octeon.o File: ./drivers/spi/spi-cavium.o File: ./drivers/spi/spi.o . . . Look for files where the size of the __jump_table section is not a integer multiple of the entsize. > Thanks, > > -Jason