From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yury Norov Subject: Re: [PATCH v5 00/30] ARM Scalable Vector Extension (SVE) Date: Mon, 8 Jan 2018 17:49:05 +0300 Message-ID: <20180108144905.qu5qbmaaglcgwvwq@yury-thinkpad> References: <1509465082-30427-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1509465082-30427-1-git-send-email-Dave.Martin@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Dave Martin Cc: Okamoto Takayuki , Szabolcs Nagy , Catalin Marinas , Will Deacon , "H. Peter Anvin" , kvmarm@lists.cs.columbia.edu, linux-arch@vger.kernel.org, Ingo Molnar , Michael Kerrisk , Alan Hayward , "H . J . Lu" , Alexander Viro , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, libc-alpha@sourceware.org, Ard Biesheuvel , Dmitry Safonov , Oleg Nesterov , linux-api@vger.kernel.org List-Id: linux-api@vger.kernel.org On Tue, Oct 31, 2017 at 03:50:52PM +0000, Dave Martin wrote: > This series implements Linux kernel support for the ARM Scalable Vector > Extension (SVE). [1] It supersedes the previous v3: see [3] for link > and full cover letter. > > This is a minor update to v4, but does contain a couple of important > fixes. > > As in previous postings, the last two patches (here 29-30) are still > RFC and not proposed for merging at this time. > > The patches apply on > git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git > for-next/core > d7b1d22d3821 ("arm64: uapi: Remove PSR_Q_BIT") > > To reduce spam, some people may not been copied on the entire series. > For those who did not receive the whole series, it can be found in the > linux-arm-kernel archive. [2] > > See the individual patches for details of changes. > > For reviewer convenience, a git tree is available. [4] > > Since there are some changes against already-reviewed patches, I've also > pushed an unsquashed fixes tree for people to take a look at if it > helps. [5] > > > Summary: > > * "regset: Add support for dynamically sized regsets" fixed to avoid > x86 breakage; > > * one trival arm64 patch added to add asmlinkage annotations, and a > corresponding minor change to the Core task context handling patch; > > * one new arm64 fix ("signal: Verify extra data is user-readable in > sys_rt_sigreturn") to ensure that access_ok() checks are done for the > whole extended signal frame, not just the base frame; > > * one minor fix to the SVE sigreturn code to return consistent > intermediate error values (semantic correctness, non-functional > change); > > * one minor change to call __copy_from_user() instead of > copy_from_user() in a situation where there is already an access_ok() > check; > > > [1] ARM Scalable Vector Extension > https://community.arm.com/groups/processors/blog/2016/08/22/technology-update-the-scalable-vector-extension-sve-for-the-armv8-a-architecture > > [2] linux-arm-kernel October 2017 Archives by thread > http://lists.infradead.org/pipermail/linux-arm-kernel/2017-October/thread.html > > [3] [PATCH v4 00/28] ARM Scalable Vector Extension (SVE) > http://lists.infradead.org/pipermail/linux-arm-kernel/2017-October/539414.html > > [4] For review and testing only -- **do not pull** > (This branch has review changelogs which should not form part of > the final commits.) > > v5 series (this posting) > > http://linux-arm.org/git?p=linux-dm.git;a=shortlog;h=refs/heads/sve/v5 > git://linux-arm.org/linux-dm.git sve/v5 > > [5] For review and testing only -- **do not pull** > (This branch has review changelogs which should not form part of > the final commits.) > > v4 with unsquashed fixes > > http://linux-arm.org/git?p=linux-dm.git;a=shortlog;h=refs/heads/sve/v4%2Bfixes > git://linux-arm.org/linux-dm.git sve/v4+fixes Hi Dave, During rebase of my ILP32 series on 4.15 kernel I found that ILP32 needs to be enabled with SVE support, like you do for LP64 in this series. I did all rebase work on this draft branch: https://github.com/norov/linux/tree/ilp32-4.15-rc7 But any ILP32 program I tried crash, and the message in dmesg looks like this: [ 39.510667] CPU: 0 PID: 1857 Comm: mytime Not tainted 4.15.0-rc7-00028-g45e0659df4d9 #41 [ 39.510712] Hardware name: linux,dummy-virt (DT) [ 39.510829] pstate: 00000000 (nzcv daif -PAN -UAO) [ 39.511101] pc : 0x33488e28 [ 39.511125] lr : 0x33488e28 [ 39.511138] sp : 00000000fffef670 [ 39.511158] x29: 000000005a536c33 x28: 0000000000000000 [ 39.511211] x27: 0000000000000000 x26: 0000000000000000 [ 39.511235] x25: 0000000000000000 x24: 0000000000000000 [ 39.511257] x23: 0000000000466000 x22: 0000000000000000 [ 39.511278] x21: 0000000000000000 x20: 000000000047f2a8 [ 39.511300] x19: 0000000000000000 x18: 0000000000000001 [ 39.511321] x17: 0000000000001000 x16: 0000000000001030 [ 39.511342] x15: 0000000000554e47 x14: 0000000000000001 [ 39.511364] x13: 0000000000000004 x12: 000000000000003c [ 39.511385] x11: 0000100000000000 x10: 0800000000000000 [ 39.511406] x9 : 0fffffffffffffff x8 : 000000000000007c [ 39.511427] x7 : 0000000000000077 x6 : 0000000000000041 [ 39.511448] x5 : 0000000000000411 x4 : 00000000fbad2488 [ 39.511468] x3 : 0000000000000001 x2 : 0000000000497950 [ 39.511489] x1 : 0000000000497550 x0 : 0000000000000001 (PC, LR and other registers may differ depending on test) I'm pretty sure that this is SVE-related issue because if I disable ARM64_SVE in config, everything becomes working. I didn't get deep enough into this yet, and most probably there's some stupid reason for crashing apps on my side, but in mail list I found some sve-related patches that I cannot apply both on 4.15-rc and next-20180108. And according to patch names, it is important fixes, like this one: https://www.spinics.net/lists/arm-kernel/msg619548.html ILP32 code may spit some kernel issues from time to time, so there's minor chance that the problem is not in ILP32 itself - that's why I write this email to you. What I want to ask you, do you have some branch with the most recent SVE code that includes all fixes? Better if it would be 4.15-based series, because we don't support ILP32 on next-* kernels now. Also, if you have few minutes to take look at my series, I would kindly ask you do this, because I still think that this is my misunderstanding of how SVE should work for ILP32, and you as author may just catch the bug at a glance. Thanks, Yury