[LLVM-494] LLD is now turned on for clang linux kernel defconfig builds
[LLVM-542] Worked out how to get Zephyr (Linaro's choice of IoT
embedded OS) compiling with clang. Looks like it is going to be
difficult to get linking with clang/lld so I've used the gcc/ld.bfd
for now.
Linux kernel sent a draft patch to try and alleviate some object
ordering problems that arise when linking the linux kernel with LTO.
[Misc]
Intel patch to add CET to LLD https://reviews.llvm.org/D58102
I mention this as this is related to BTI and CFI and
.note.gnu.property sections. There has been some pushback to the use
of .note.gnu.property sections, and in Intel's case their 2 level PLT
scheme although it seems like as this has been mitigated by the
presence of this option in gcc for some time. I have noticed that we
tend to do design of a feature in one community (LLVM, GNU) and then
attempt to win over the other one with leverage that the other
community supports it. We may need to cast our early feedback net a
bit wider to mitigate the chance that one of the communities blocks
one of our features.
There was an interesting RFC on a linker feature for improving
code-size for mobile phones
http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html in
essence an application is developed with loadable features implemented
in DSOs loaded by dlopen. The entry points of the DSO are recorded,
then all the input objects are given to the static linker which then
performs LTO and creates stripped down DSOs that must be loaded at a
specific offset from the application (shrinking them but losing the
shared part of DSO).
QEMU Tooling ([VIRT-252])
=========================
QEMU plugin support ([VIRT-280])
- posted {PATCH v3 0/3} softmmu demacro Message-Id:
<20190215143115.28777-1-alex.bennee(a)linaro.org>
- looks like there is still a bug on x86 TCG Message-Id:
<20190219182528.GA19925@flamenco>
- started v4 re-base, but realised we need better testing so
- posted {PATCH v2 00/16} Enabling tcg/tests for cris and system
mode xtensa & arm Message-Id:
<c3a65d4b-8720-2957-1394-032823a78760(a)redhat.com>
- started writing an i386 test case (x86 exercises more of the
softmmu edge cases)
- started reviewing v3 of plugin patches
[VIRT-280] https://projects.linaro.org/browse/VIRT-280
Upstream Work ([VIRT-109])
==========================
- posted {PATCH v5} hw/block: better reporting on pflash backing file
mismatch Message-Id: <20190227111347.15063-1-alex.bennee(a)linaro.org>
- tested the possible ahci/migrate fix Message-Id:
<20190227121052.GD2602@work-vm> for hang identified last week
- posted {PULL 0/7} softfloat updates, mostly for s390x Message-Id:
<20190226141201.16999-1-alex.bennee(a)linaro.org>
- posted {PATCH v1 0/6} current state of gitdm/next Message-Id:
<20190226164656.mhasc4xxfjf34hns@function>
- and follow-up {PATCH v2 0/5} gitdm/next updates Message-Id:
<20190301100310.22345-4-alex.bennee(a)linaro.org>
- added some stats to VIRT-26/VIRT-326 for possible KPI use
[VIRT-109] https://projects.linaro.org/browse/VIRT-109
Other
=====
- more drafting of Connect talk
Completed Reviews [1/1]
=======================
{PATCH v2 00/11} pflash: Fixes and cleanups
Message-Id: <20190226193408.23862-5-armbru(a)redhat.com>
- CLOSING NOTE [2019-03-01 Fri 16:59]
Looks like a good cleanup
Absences
========
- Connect BKK19 (1-5th April 2019)
- holiday after Connect
Current Review Queue
====================
* {RFC v2 00/38} Plugin support
Message-Id: <20181209193749.12277-1-cota(a)braap.org>
* {Qemu-devel} {PATCH 00/23} tests/tcg/xtensa: conditionalize xtensa tests
Message-Id: <20190219061111.10231-1-jcmvbkbc(a)gmail.com>
* {PATCH 00/10} Rework debug exception handling code
Message-Id: <20190301132809.24653-7-will.deacon(a)arm.com>
* {PATCH v2 00/11} Enable build and install of our rST docs
Message-Id: <20190228145624.24885-1-peter.maydell(a)linaro.org>
* {PATCH+RFC 0/6} target/arm: Define cortex-a{73,75,76}
Message-Id: <20190223023957.18865-1-richard.henderson(a)linaro.org>
* {PATCH v3 00/20} Acceptance Tests: target architecture support
Message-Id: <20190221005753.27955-1-crosa(a)redhat.com>
--
Alex Bennée
== Progress ==
* [Thumb GlobalISel] Support global variables [LLVM-540]
- Committed upstream
* [Thumb GlobalISel] Support G_CTLZ [LLVM-543]
- Committed upstream
- We now have the same level of support for Thumb2 and ARM mode
* LLVM 8.0.0 Release for ARM & AArch64 [LLVM-526]
- Tested and uploaded rc3
== Plan ==
* Out of office between 4 - 8 March (i.e. next week)
* GlobalISel bugfixing and cleanup (both ARM and Thumb2)
== Progress ==
* PR88836
- I have a patch (for backend and CSE) which now passes bootstrap and
regression except for one testcase failure (which looks like a pattern
issue). Looking into it.
* Look at GDB BZ #21221 - gdb hangs while stepping an empty loop
- Not convinced that it is a gcc issue. Looking into the dwarf specification.
* PR88838
- Looking at it.
- Also familiarising with auto-vectorisation of SVE
== Plan ==
* Complete above PRs
* Look at GDB BZ #21221 - gdb hangs while stepping an empty loop
[LLVM-158] Monitor and maintain buildbots
- Some work to track down a faulty msan test on AArch64 that was
intermittently failing.
- Spent some time trying to reproduce an intermittent failure in libfuzzer.
[LLVM-523] Synthesise EXIDX_CANTUNWIND entries for sections without tables.
- Not getting much response from upstream beyond a vague suggestion to
rewrite the whole of .ARM.exidx handling as a single custom section. I
may have to go down this path to get the feature accepted, even if it
is to show that it is a bad idea.
[LLVM-496] LLD in linux kernel
- Submitted patch to ignore -p (--no-pipeline-knowledge) which is used
by the AArch32 linux kernel.
- Submitted patch to integrate LLD in TCWG kernel regression test.
- Learned, the hard way, about how the linux kernel build system works
and how to pass extra flags.
Reviews:
Spent an awful long time looking at how clang passes options to GNU as
to try and match the existing clang defaults. I'm not sure I've seen
anything much more confusing than tracing through target features from
clang to llvm and back again.
re-essayer de flash le kernel sur la board (mais est-ce possible vu
qu'il semble plus gros que la flash?)
$ openocd -f /usr/share/openocd/scripts/board/stm32f429discovery.cfg
-f flash-kernel.cfg
[...]
Info : device id = 0x20016419
Info : flash size = 2048kbytes
Info : Dual Bank 2048 kiB STM32F42x/43x/469/479 found
Warn : no flash bank found for address 0
wrote 0 bytes from file
/home/lyon/src/kernel/linux/arch/arm/boot/xipImage in 0.007352s (0.000
KiB/s)
** Programming Finished **
demander de l'aide aux gens de ST?
re-essayer avec un openocd plus recent
== Progress ==
* FDPIC
- (GNU-411) GDB: debugging problems with FDPIC support. Trying to
setup a stm32 board to avoid problems with unsupported configurations
mix between kernel and qemu.
* GCC upstream validation:
- reported a few regressions
* GCC:
- (GNU-99) ubsan / bare-metal. No progress.
* misc (conf-calls, meetings, emails, ....)
- reviewing infra script patches
- debugging new benchmarking round-robin jobs
== Next ==
Holidays, back on March 4th
== Next-next ==
FDPIC:
- GCC: handle feedback on v4 patches
- GDB: update patches
- uclibc-ng: look at how to test fdpic mode with openadk
- complete board setup
Infra:
- benchmarking jobs
Progress:
* VIRT-65 [QEMU upstream maintainership]
+ patch review: RTH's JSConv/FHM patchset
+ sent another arm pull request
* VIRT-268 [QEMU support for dual-core Cortex-M Musca board]
+ Implemented and wired up the SSE-200 Message Handling Units
+ Implemented the mechanism by which a guest can power up CPU 1
+ Sent out patches for these; this can run the Zephyr MHU/dualcore testcase
+ Started looking at implementing floating point support for M profile
thanks
-- PMM
== Progress ==
* [Thumb GlobalISel] Support control flow [LLVM-530]
- Committed upstream
* [Thumb GlobalISel] Support accessing the stack [LLVM-527]
- Committed upstream
* [Thumb GlobalISel] Support floating point [LLVM-531]
- Committed upstream
* LLVM 8.0.0 Release for ARM & AArch64 [LLVM-526]
- Investigated the release blocker from rc1, turned out to be an
issue with the filesystem used in the container on the APMs
- Changed the release job to run on the D05 instead, where we use a
different container [LLVM-539]
- Testing still in progress
== Plan ==
* [Thumb GlobalISel] Support global variables [LLVM-540]
* Out of office between 4 - 8 March
== Progress ==
* PR88834:
* Have a patch for ivopt and backend that generates the required
addressing mode and code. Still need cleanup and some improvements.
* PR88836
Made the required changes to the backend.
CSE is still not happening. Looked at CSE in detail and made few
changes but still need more work. The issues are:
- Parallel rtx with one setting a register and other using it will
be immediately invalidated as the invalidation happens after
processing both.
- If CSE is such that one instruction is with one constant operand
and other with constant in a register, it will not be detected
- VEC_DUPLICATE is not handled.
- Not sure any other pass like GCSE is a better option
== Plan ==
* Complete above PRs
* Look at GDB BZ #21221 - gdb hangs while stepping an empty loop
[VIRT-68 # QEMU should implement tagged pointer support ]
Closed. We merged these patches on Feb 5.
[VIRT-242 # ARMv8.3-JSCVT ]
Sent v4.
[VIRT-274 # ARMv8.2-FHM, Floating-point multiplication variant ]
Sent v2.
[VIRT-344 # ARMv8.5-MemTag, Memory Tagging Extension ]
Sent v3 vs 00eac6.
[VIRT-327 # Richard's upstream QEMU work ]
Reviewed s390 floating point extension feature.
Fixed AT_PLATFORM for arm-linux-user and aarch64_be-linux-user.
Implemented missing float_round_to_odd functionality.
r~
QEMU Tooling ([VIRT-252])
=========================
[VIRT-280] https://projects.linaro.org/browse/VIRT-280
QEMU plugin support ([VIRT-280])
- posted {PATCH v3 0/3} softmmu demacro Message-Id:
<20190215143115.28777-1-alex.bennee(a)linaro.org>
- awaiting v3 of plugin patches :todo
Upstream Work ([VIRT-109])
==========================
- posted {PULL 00/18} testing updates: travis/cirrus/vm-test/binfmt
Message-Id: <20190211130507.8710-1-alex.bennee(a)linaro.org>
- posted {PATCH v2 0/6} HWCAP_CPUID registers for aarch64 Message-Id:
<20190205190224.2198-1-alex.bennee(a)linaro.org>
- fixes pulled into target-arm.next
- test case held back due to compiler version needed, need to respin
- posted {PATCH v2} hw/block: report when pflash backing file isn't
aligned Message-Id: <20190215122808.22301-1-alex.bennee(a)linaro.org>
- prompted further discussion on best solution as -pflash fails in
ways -bios doesn't
[VIRT-109] https://projects.linaro.org/browse/VIRT-109
Other
=====
- Spent time building cross-tools for Debian/ARM64
- sent {PATCH} binutils: enable s390x/ppc64el on arm64 hosts
Message-Id: <20190212140851.22478-1-alex.bennee(a)linaro.org>
- Discussion on [Debian #921458] (buster apt source qemu)
- upstream consensus seems to be it is acceptable
- apt-get build-dep --arch-only qemu
[Debian #921458]
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=921458
Completed Reviews [1/1]
=======================
{RFC} arm: Allow system registers for KVM guests to be changed by QEMU code
Message-Id: <20181206151401.13455-1-peter.maydell(a)linaro.org>
- CLOSING NOTE [2019-02-13 Wed 16:30]
Looks fine, although we still need to keep squashing single-step
while debug is on
Absences
========
- 15-18th Feb (long w/e)
- Connect BKK19 (1-5th April 2019)
- holiday after Connect
Current Review Queue
====================
* {PATCH 0/4} target/arm: Reduce overhead of cpu_get_tb_cpu_state
Message-Id: <20190214040652.4811-1-richard.henderson(a)linaro.org>
* {RFC v2 00/38} Plugin support
Message-Id: <20181209193749.12277-1-cota(a)braap.org>
* {Qemu-devel} {PATCH v6 00/49} linux-user: Split do_syscall
Message-Id: <20190118213122.22865-1-richard.henderson(a)linaro.org>
* {PATCH 0/5} target/mips: Add MSA ASE tests
Message-Id: <1550001205-7883-1-git-send-email-aleksandar.markovic(a)rt-rk.com>
* {Qemu-arm} {PATCH 00/25} Kconfig dependencies for ARM machines
Message-Id: <1549694366-1284-1-git-send-email-thuth(a)redhat.com>
* {RFC QEMU v2 0/2} arm/virt: Account for guest pause time
Message-Id: <1543352837-21529-1-git-send-email-bijan.mottahedeh(a)oracle.com>
--
Alex Bennée
Progress:
* VIRT-65 [QEMU upstream maintainership]
+ usual code review/maintainer work
+ Coverity Scan is back up; triaged the issues that it found
+ updated OSX "handle Mojave" patchset to actually wire
up events correctly; sent v2
* VIRT-268 [QEMU support for dual-core Cortex-M Musca board]
+ Finished, tested and sent out the initial Musca board model
patches for review
+ Fixed a handful of random bugs identified in the course
of doing this and testing it with various guests
+ Investigated why tip-of-trunk ARM-TFM stopped working on
the mps2-an521 model; turned out to be a QEMU bug which I have
sent out a patch for
thanks
-- PMM
== Progress ==
* [Thumb GlobalISel] Support G_SELECT [LLVM-529]
- Committed upstream
* [Thumb GlobalISel] Support control flow [LLVM-530]
- Committed support for branches
- Support for PHI in progress
* LLVM 8.0.0 Release for ARM & AArch64 [LLVM-526]
- rc2 uploaded, no changes from rc1 on our side
* Use new version of GCC on buildbots [LLVM-515]
- Restarted the buildbots, they are running GCC 7 now
* Buildbot babysitting [LLVM-158]
- Reproduced a couple of failures, ran a pre-commit for one of them
== Plan ==
* Continue LLVM-526 and LLVM-530
== This Week ==
* SVE ACLE (4/10)
- Committed svlsl patch to branch
* SVE (3/10)
- Studying GCC's vectorizer
- Started looking at PR88839
* Validation (2/10)
- GNU-156: Working on tcwg_gnu CI job.
* Misc (1/10)
- Meetings
- Filed PR89332 in GCC bugzilla.
== Next Week ==
- Continue ongoing tasks
[VIRT-242 # ARMv8.3-JSCVT ]
Posted v1 & v2.
[VIRT-339 # ARMv8.5-BTI, Branch Target Identification ]
Posted v3.
[VIRT-327 # Richard's upstream QEMU work ]
Posted v3 of arm tcg vector improvements. Now uses ssadd & usadd tcg opcodes
from AdvSIMD and not just SVE. This would have made it easier to find a bug in
my previous tcg backend patches.
Found the last two bugs in a conversion of target/hppa to decodetree, and
posted the patch set. Sent pull request for some other queued hppa patches.
Fix a minor RISU bug wrt SVE.
[LoAAS]
Travel to/from Cambridge for 2 days of Linux on ARM Summit.
r~
== Progress ==
* FDPIC
- (GNU-411) GDB: debugging problems with FDPIC support.
* GCC upstream validation:
- reported a few regressions, helping test patches
- dealing with some random results, still
* GCC:
- (GNU-99) rebased ubsan / bare-metal patches. No progress.
* misc (conf-calls, meetings, emails, ....)
- reviewing/submitted infra script patches
- debugging new benchmarking round-robin jobs
== Next ==
FDPIC:
- GCC: handle feedback on v4 patches
- GDB: update patches
- uclibc-ng: look at how to test fdpic mode with openadk
Infra:
- benchmarking jobs
QEMU Tooling ([VIRT-252])
=========================
QEMU plugin support ([VIRT-280])
- re-based [ldst demacro to v3]
- recollect stats to see if slowdown still there :todo
- awaiting v3 of plugin patches
[VIRT-280] https://projects.linaro.org/browse/VIRT-280
[ldst demacro to v3]
https://github.com/stsquad/qemu/tree/ldst/demacrofy-v3
Upstream Work ([VIRT-109])
==========================
- need to finish the re-work of [system test and misc arch] tests
:todo
- will be useful for test cases for plugins
- also more test cases queued up for system tests
- debugged an occasional failure in pauth-1 test case
- expected given PAuth architecture, test needs tightening up
- posted {PATCH v1 0/4} HWCAP_CPUID registers for aarch64 Message-Id:
<20190128173940.25813-1-alex.bennee(a)linaro.org>
- posted {PATCH v2 0/6} HWCAP_CPUID registers for aarch64 Message-Id:
<20190205190224.2198-1-alex.bennee(a)linaro.org>
- posted {PATCH v2 00/16} current testing/next queue (with build
fixes) Message-Id: <20190207183744.5054-1-alex.bennee(a)linaro.org>
- this fixes regression of check-tcg but also
- discovered the Debian Buster's QEMU arm64 packaging is broken
- spent time trying to able to join #debian's IRC channels (aws
hosts banned!)
- tried to revive the cross-tools packaging I'd started with Wookey
last Connect
[VIRT-109] https://projects.linaro.org/browse/VIRT-109
[the linux-user multiarch but it is not ready yet]
https://github.com/stsquad/qemu/tree/testing/next-with-linux-user
[system test and misc arch]
https://github.com/stsquad/qemu/tree/testing/enable-system-tcg-tests-v2
Other
=====
- Connect talk has been accepted, Friday 8.30 slot
Completed Reviews [1/1]
=======================
{Qemu-arm} {PATCH v6 00/73} per-CPU locks
Message-Id: <20190130004811.27372-1-cota(a)braap.org>
- CLOSING NOTE [2019-02-08 Fri 17:19]
Looks good, improves MTTCG scalability to 10-12 core now ;-)
Absences
========
- 15-18th Feb (long w/e)
- Connect BKK19 (1-5th April 2019)
- holiday after Connect
Current Review Queue
====================
* {RFC} arm: Allow system registers for KVM guests to be changed by QEMU code
Message-Id: <20181206151401.13455-1-peter.maydell(a)linaro.org>
* {RFC v2 00/38} Plugin support
Message-Id: <20181209193749.12277-1-cota(a)braap.org>
* {RFC QEMU v2 0/2} arm/virt: Account for guest pause time
Message-Id: <1543352837-21529-1-git-send-email-bijan.mottahedeh(a)oracle.com>
* {PATCH v12 00/25} Fixing record/replay and adding reverse debugging
Message-Id: <154935478086.7509.4349987292919289245.stgit@pasha-VirtualBox>
* {PATCH v2 00/18} OpenBSD: Enable qtesting
Message-Id: <20190129175403.18017-1-philmd(a)redhat.com>
* {PATCH v11 00/25} Fixing record/replay and adding reverse debugging
Message-Id: <20190131131520.23264.75724.stgit@pasha-VirtualBox>
--
Alex Bennée
Fosdem:
- Presented on LLD performance at LLVM devroom
https://fosdem.org/2019/schedule/track/llvm/
- Other interesting presentations from the devroom include:
-- Compiling the Linux kernel with LLVM tools
-- Lessons in TableGen
LLVM-523 LLD should synthesise .cantunwind .ARM.exidx sections for
sections without them
- Implementation and regression tests done. Will do a bit more testing
and post upstream on Monday.
LLVM-521 Taking the address of an ifunc in LLD
- Spent some time reviewing upstream patch that should fix the
remaining LLD ifunc address equivalence problems for all Targets.
Progress:
* VIRT-65 [QEMU upstream maintainership]
+ reviewed RTH's patchsets for BTI and MemTag support
* VIRT-268 [QEMU support for dual-core Cortex-M Musca board]
+ Implemented a first pass at a Musca board model, which
has the PPC and MPC infrastructure, plus RAM, and ROM for
the flash; need to add at least the UARTs and do some testing
* misc
+ sorting out travel arrangements, visa, etc for Connect
+ kicked off a discussion on whether there are aspects of
QEMU's role as the userspace component of a KVM VM that
Linaro should be putting more effort/attention into
thanks
-- PMM
== Progress ==
* Out of office on Monday
* [Thumb GlobalISel] Support G_GEP [LLVM-532]
- Committed upstream
* [Thumb GlobalISel] Support G_ICMP [LLVM-528]
- Committed upstream
* [Thumb GlobalISel] Support G_SELECT [LLVM-529]
- Almost ready to commit
* LLVM 8.0.0 Release for ARM & AArch64 [LLVM-526]
- rc2 in progress
* Minor changes to Jenkins jobs [LLVM-533]
- TCWG Regression Detection job: launch LLVM 7.0.0 release on xenial
containers (as opposed to 6.0.0 on trusty)
- Release job: forced parallelism to 3 on the TK1s, to reduce some
of the swapping; also posted a patch upstream to allow us to use
ninja, so we can limit only the number of link jobs (like we do on the
buildbots)
== Plan ==
* Continue LLVM-526 and LLVM-529
* Use new version of GCC on buildbots [LLVM-515]
- Restart the buildbots so they begin using GCC 7
