Re: [PATCH v5 00/30] ARM Scalable Vector Extension (SVE)

[Yury Norov <ynorov at caviumnetworks dot com>]

On Mon, Jan 15, 2018 at 05:22:01PM +0000, Dave Martin wrote:
> On Tue, Jan 09, 2018 at 07:51:20PM +0300, Yury Norov wrote:
> > On Mon, Jan 08, 2018 at 05:49:05PM +0300, Yury Norov wrote:
> > > 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
> > 
> > Hi Dave,
> > 
> > I fixed the crash. It was my local problem.
> 
> Ah, right :)
> 
> I'll take a look at your code anyway in case there's something
> else one of us didn't think of.

Thanks, Dave.

This is the branch:
https://github.com/norov/linux/tree/ilp32-4.15-rc7

SVE-related changes are mostly in patches:
arm64: ilp32: introduce ilp32-specific handlers for sigframe and ucontext
arm64: signal32: move ilp32 and aarch32 common code to separated file
arm64: signal: share lp64 signal structures and routines to ilp32
arm64: ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it

Yury