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[PATCH] Documentation: kunit: Make the KUnit documentation less UML-specific

by David Gow

Remove some of the outmoded "Why KUnit" rationale -- which focuses significantly on UML -- and update the Getting Started guide to mention running tests without the kunit_tool wrapper. Signed-off-by: David Gow <davidgow(a)google.com> --- This is an attempt at resolving some of the issues with the KUnit documentation pointed out here: https://lore.kernel.org/linux-kselftest/CABVgOSkiLi0UNijH1xTSvmsJEE5+ocCZ7n… There's definitely room for further work on the KUnit documentation (e.g., adding more information around the environment tests run in), but this hopefully is better than nothing as a starting point. Documentation/dev-tools/kunit/index.rst | 60 ++++--------------- Documentation/dev-tools/kunit/start.rst | 80 +++++++++++++++++++++---- 2 files changed, 78 insertions(+), 62 deletions(-) diff --git a/Documentation/dev-tools/kunit/index.rst b/Documentation/dev-tools/kunit/index.rst index d16a4d2c3a41..6064cd14dfad 100644 --- a/Documentation/dev-tools/kunit/index.rst +++ b/Documentation/dev-tools/kunit/index.rst @@ -17,63 +17,23 @@ What is KUnit? ============== KUnit is a lightweight unit testing and mocking framework for the Linux kernel. -These tests are able to be run locally on a developer's workstation without a VM -or special hardware. KUnit is heavily inspired by JUnit, Python's unittest.mock, and Googletest/Googlemock for C++. KUnit provides facilities for defining unit test cases, grouping related test cases into test suites, providing common infrastructure for running tests, and much more. -Get started now: :doc:`start` - -Why KUnit? -========== - -A unit test is supposed to test a single unit of code in isolation, hence the -name. A unit test should be the finest granularity of testing and as such should -allow all possible code paths to be tested in the code under test; this is only -possible if the code under test is very small and does not have any external -dependencies outside of the test's control like hardware. - -Outside of KUnit, there are no testing frameworks currently -available for the kernel that do not require installing the kernel on a test -machine or in a VM and all require tests to be written in userspace running on -the kernel; this is true for Autotest, and kselftest, disqualifying -any of them from being considered unit testing frameworks. +KUnit consists of a kernel component, which provides a set of macros for easily +writing unit tests. Tests written against KUnit will run on kernel boot if +built-in, or when loaded if built as a module. These tests write out results to +the kernel log in `TAP <https://testanything.org/>`_ format. -KUnit addresses the problem of being able to run tests without needing a virtual -machine or actual hardware with User Mode Linux. User Mode Linux is a Linux -architecture, like ARM or x86; however, unlike other architectures it compiles -to a standalone program that can be run like any other program directly inside -of a host operating system; to be clear, it does not require any virtualization -support; it is just a regular program. +To make running these tests (and reading the results) easier, KUnit offsers +:doc:`kunit_tool <kunit-tool>`, which builds a `User Mode Linux +<http://user-mode-linux.sourceforge.net>`_ kernel, runs it, and parses the test +results. This provides a quick way of running KUnit tests during development. -Alternatively, kunit and kunit tests can be built as modules and tests will -run when the test module is loaded. - -KUnit is fast. Excluding build time, from invocation to completion KUnit can run -several dozen tests in only 10 to 20 seconds; this might not sound like a big -deal to some people, but having such fast and easy to run tests fundamentally -changes the way you go about testing and even writing code in the first place. -Linus himself said in his `git talk at Google -<https://gist.github.com/lorn/1272686/revisions#diff-53c65572127855f1b003db4…>`_: - - "... a lot of people seem to think that performance is about doing the - same thing, just doing it faster, and that is not true. That is not what - performance is all about. If you can do something really fast, really - well, people will start using it differently." - -In this context Linus was talking about branching and merging, -but this point also applies to testing. If your tests are slow, unreliable, are -difficult to write, and require a special setup or special hardware to run, -then you wait a lot longer to write tests, and you wait a lot longer to run -tests; this means that tests are likely to break, unlikely to test a lot of -things, and are unlikely to be rerun once they pass. If your tests are really -fast, you run them all the time, every time you make a change, and every time -someone sends you some code. Why trust that someone ran all their tests -correctly on every change when you can just run them yourself in less time than -it takes to read their test log? +Get started now: :doc:`start` How do I use it? ================ @@ -81,3 +41,5 @@ How do I use it? * :doc:`start` - for new users of KUnit * :doc:`usage` - for a more detailed explanation of KUnit features * :doc:`api/index` - for the list of KUnit APIs used for testing +* :doc:`kunit-tool` - for more information on the kunit_tool helper script +* :doc:`faq` - for answers to some common questions about KUnit diff --git a/Documentation/dev-tools/kunit/start.rst b/Documentation/dev-tools/kunit/start.rst index 4e1d24db6b13..e1c5ce80ce12 100644 --- a/Documentation/dev-tools/kunit/start.rst +++ b/Documentation/dev-tools/kunit/start.rst @@ -9,11 +9,10 @@ Installing dependencies KUnit has the same dependencies as the Linux kernel. As long as you can build the kernel, you can run KUnit. -KUnit Wrapper -============= -Included with KUnit is a simple Python wrapper that helps format the output to -easily use and read KUnit output. It handles building and running the kernel, as -well as formatting the output. +Running tests with the KUnit Wrapper +==================================== +Included with KUnit is a simple Python wrapper which runs tests under User Mode +Linux, and formats the test results. The wrapper can be run with: @@ -21,22 +20,42 @@ The wrapper can be run with: ./tools/testing/kunit/kunit.py run --defconfig -For more information on this wrapper (also called kunit_tool) checkout the +For more information on this wrapper (also called kunit_tool) check out the :doc:`kunit-tool` page. Creating a .kunitconfig -======================= -The Python script is a thin wrapper around Kbuild. As such, it needs to be -configured with a ``.kunitconfig`` file. This file essentially contains the -regular Kernel config, with the specific test targets as well. - +----------------------- +If you want to run a specific set of tests (rather than those listed in the +KUnit defconfig), you can provide Kconfig options in the ``.kunitconfig`` file. +This file essentially contains the regular Kernel config, with the specific +test targets as well. The ``.kunitconfig`` should also contain any other config +options required by the tests. + +A good starting point for a ``.kunitconfig`` is the KUnit defconfig: .. code-block:: bash cd $PATH_TO_LINUX_REPO cp arch/um/configs/kunit_defconfig .kunitconfig -Verifying KUnit Works ---------------------- +You can then add any other Kconfig options you wish, e.g.: +.. code-block:: none + + CONFIG_LIST_KUNIT_TEST=y + +:doc:`kunit_tool <kunit-tool>` will ensure that all config options set in +``.kunitconfig`` are set in the kernel ``.config`` before running the tests. +It'll warn you if you haven't included the dependencies of the options you're +using. + +.. note:: + Note that removing something from the ``.kunitconfig`` will not trigger a + rebuild of the ``.config`` file: the configuration is only updated if the + ``.kunitconfig`` is not a subset of ``.config``. This means that you can use + other tools (such as make menuconfig) to adjust other config options. + + +Running the tests +----------------- To make sure that everything is set up correctly, simply invoke the Python wrapper from your kernel repo: @@ -62,6 +81,41 @@ followed by a list of tests that are run. All of them should be passing. Because it is building a lot of sources for the first time, the ``Building KUnit kernel`` step may take a while. +Running tests without the KUnit Wrapper +======================================= + +If you'd rather not use the KUnit Wrapper (if, for example, you need to +integrate with other systems, or use an architecture other than UML), KUnit can +be included in any kernel, and the results read out and parsed manually. + +.. note:: + KUnit is not designed for use in a production system, and it's possible that + tests may reduce the stability or security of the system. + + + +Configuring the kernel +---------------------- + +In order to enable KUnit itself, you simply need to enable the ``CONFIG_KUNIT`` +Kconfig option (it's under Kernel Hacking/Kernel Testing and Coverage in +menuconfig). From there, you can enable any KUnit tests you want: they usually +have config options ending in ``_KUNIT_TEST``. + +KUnit and KUnit tests can be compiled as modules: in this case the tests in a +module will be run when the module is loaded. + +Running the tests +----------------- + +Build and run your kernel as usual. Test output will be written to the kernel +log in `TAP <https://testanything.org/>`_ format. + +.. note:: + It's possible that there will be other lines and/or data interspersed in the + TAP output. + + Writing your first test ======================= -- 2.25.0.341.g760bfbb309-goog

5 years, 7 months

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[PATCH] Removing a duplicate condition.

by Isaac Young

Signed-off-by: Isaac Young <isaac.young5(a)gmail.com> --- tools/testing/selftests/bpf/prog_tests/select_reuseport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/select_reuseport.c b/tools/testing/selftests/bpf/prog_tests/select_reuseport.c index 098bcae5f827..0954c7a8aa08 100644 --- a/tools/testing/selftests/bpf/prog_tests/select_reuseport.c +++ b/tools/testing/selftests/bpf/prog_tests/select_reuseport.c @@ -823,7 +823,7 @@ void test_select_reuseport(void) saved_tcp_fo = read_int_sysctl(TCP_FO_SYSCTL); saved_tcp_syncookie = read_int_sysctl(TCP_SYNCOOKIE_SYSCTL); - if (saved_tcp_syncookie < 0 || saved_tcp_syncookie < 0) + if (saved_tcp_syncookie < 0) goto out; if (enable_fastopen()) -- 2.24.1

5 years, 7 months

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next-20200211 kselftest results

by ci_notify＠linaro.org

Summary ------------------------------------------------------------------------ kernel: 5.6.0-rc1 git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git branch: master git commit: ac431e2d7b1be81bfe58163b9f81ba79bc987dc3 git describe: next-20200211 Test details: https://qa-reports.linaro.org/lkft/linux-next-oe/build/next-20200211 Regressions (compared to build next-20200117) ------------------------------------------------------------------------ No regressions Fixes (compared to build next-20200117) ------------------------------------------------------------------------ No fixes In total: ------------------------------------------------------------------------ Ran 0 total tests in the following environments and test suites. pass 0 fail 0 xfail 0 skip 0 Environments -------------- - dragonboard-410c - arm64 - hi6220-hikey - arm64 - i386 - juno-r2 - arm64 - x15 - arm - x86_64 Test Suites ----------- Failures ------------------------------------------------------------------------ juno-r2: x15: x86: i386: hi6220-hikey: dragonboard-410c: Skips ------------------------------------------------------------------------ No skips -- Linaro LKFT https://lkft.linaro.org

5 years, 7 months

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[PATCH] Documentation: kunit: fix Sphinx directive warning

by Randy Dunlap

From: Randy Dunlap <rdunlap(a)infradead.org> Fix Documentation warning due to missing a blank line after a directive: linux/Documentation/dev-tools/kunit/usage.rst:553: WARNING: Error in "code-block" directive: maximum 1 argument(s) allowed, 3 supplied. .. code-block:: bash modprobe example-test Fixes: 6ae2bfd3df06 ("kunit: update documentation to describe module-based build") Signed-off-by: Randy Dunlap <rdunlap(a)infradead.org> Cc: Alan Maguire <alan.maguire(a)oracle.com> Cc: Knut Omang <knut.omang(a)oracle.com> Cc: Brendan Higgins <brendanhiggins(a)google.com> Cc: linux-kselftest(a)vger.kernel.org Cc: kunit-dev(a)googlegroups.com Cc: Shuah Khan <skhan(a)linuxfoundation.org> --- Documentation/dev-tools/kunit/usage.rst | 1 + 1 file changed, 1 insertion(+) --- lnx-56-rc1.orig/Documentation/dev-tools/kunit/usage.rst +++ lnx-56-rc1/Documentation/dev-tools/kunit/usage.rst @@ -551,6 +551,7 @@ options to your ``.config``: Once the kernel is built and installed, a simple .. code-block:: bash + modprobe example-test ...will run the tests.

5 years, 7 months

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[RESEND PATCH v9 00/13] selftests/resctrl: Add resctrl selftest

by Fenghua Yu

[Resend the v9 patch set to Shuah Khan and linux-kselftest mailing list. No code and commit message change.] With more and more resctrl features are being added by Intel, AMD and ARM, a test tool is becoming more and more useful to validate that both hardware and software functionalities work as expected. We introduce resctrl selftest to cover resctrl features on X86, AMD and ARM architectures. It first implements MBM (Memory Bandwidth Monitoring), MBA (Memory Bandwidth Allocation), L3 CAT (Cache Allocation Technology), and CQM (Cache QoS Monitoring) tests. We will enhance the selftest tool to include more functionality tests in the future. The tool has been tested on Intel RDT, AMD QoS and ARM MPAM and is in tools/testing/selftests/resctrl in order to have generic test code base for all architectures. The selftest tool we are introducing here provides a convenient tool which does automatic resctrl testing, is easily available in kernel tree, and covers Intel RDT, AMD QoS and ARM MPAM. There is an existing resctrl test suite 'intel_cmt_cat'. But its major purpose is to test Intel RDT hardware via writing and reading MSR registers. It does access resctrl file system; but the functionalities are very limited. And it doesn't support automatic test and a lot of manual verifications are involved. Changelog: v9: - Per Boris suggestion, add Co-developed-by in each patch to make it clear who contributed to the patch set. v8: Update code per comments from Andre Przywara from ARM: - Change Makefile and remove inline assembly code to build and test the tool on ARM - Change the output to TAP format because the format is both readable by human and other test tools. - Detect resctrl feature from /proc/cpuinfo instead of dmesg to support generic detection on all architectures. - Fix a few coding issues. v7: - Fix a few warnings when compiling patches separately, pointed by Babu v6: - Fix a benchmark reading optimized out issue in newer GCC. - Fix a few coding style issues. - Re-arrange code among patches to make cleaner code. No change in patches structure. v5: - Based the v4 patches submitted by Fenghua Yu and added changes to support AMD. - Changed the function name get_sock_num to get_resource_id. Intel uses socket number for schemata and AMD uses l3 index id. To generalize, changed the function name to get_resource_id. - Added the code to detect vendor. - Disabled the few tests for AMD where the test results are not clear. Also AMD does not have IMC. - Fixed few compile issues. - Some cleanup to make each patch independent. - Tested the patches on AMD system. Fenghua, Need your help to test on Intel box. Please feel free to change and resubmit if something broken. v4: - address comments from Balu and Randy - Add CAT and CQM tests v3: - Change code based on comments from Babu Moger - Remove some unnessary code and use pipe to communicate b/w processes v2: - Change code based on comments from Babu Moger - Clean up other places. Babu Moger (3): selftests/resctrl: Add vendor detection mechanism selftests/resctrl: Use cache index3 id for AMD schemata masks selftests/resctrl: Disable MBA and MBM tests for AMD Fenghua Yu (6): selftests/resctrl: Add README for resctrl tests selftests/resctrl: Add MBM test selftests/resctrl: Add MBA test selftests/resctrl: Add Cache QoS Monitoring (CQM) selftest selftests/resctrl: Add Cache Allocation Technology (CAT) selftest selftests/resctrl: Add the test in MAINTAINERS Sai Praneeth Prakhya (4): selftests/resctrl: Add basic resctrl file system operations and data selftests/resctrl: Read memory bandwidth from perf IMC counter and from resctrl file system selftests/resctrl: Add callback to start a benchmark selftests/resctrl: Add built in benchmark MAINTAINERS | 1 + tools/testing/selftests/resctrl/Makefile | 17 + tools/testing/selftests/resctrl/README | 53 ++ tools/testing/selftests/resctrl/cache.c | 272 +++++++ tools/testing/selftests/resctrl/cat_test.c | 250 ++++++ tools/testing/selftests/resctrl/cqm_test.c | 176 +++++ tools/testing/selftests/resctrl/fill_buf.c | 213 +++++ tools/testing/selftests/resctrl/mba_test.c | 171 ++++ tools/testing/selftests/resctrl/mbm_test.c | 145 ++++ tools/testing/selftests/resctrl/resctrl.h | 107 +++ .../testing/selftests/resctrl/resctrl_tests.c | 202 +++++ tools/testing/selftests/resctrl/resctrl_val.c | 744 ++++++++++++++++++ tools/testing/selftests/resctrl/resctrlfs.c | 722 +++++++++++++++++ 13 files changed, 3073 insertions(+) create mode 100644 tools/testing/selftests/resctrl/Makefile create mode 100644 tools/testing/selftests/resctrl/README create mode 100644 tools/testing/selftests/resctrl/cache.c create mode 100644 tools/testing/selftests/resctrl/cat_test.c create mode 100644 tools/testing/selftests/resctrl/cqm_test.c create mode 100644 tools/testing/selftests/resctrl/fill_buf.c create mode 100644 tools/testing/selftests/resctrl/mba_test.c create mode 100644 tools/testing/selftests/resctrl/mbm_test.c create mode 100644 tools/testing/selftests/resctrl/resctrl.h create mode 100644 tools/testing/selftests/resctrl/resctrl_tests.c create mode 100644 tools/testing/selftests/resctrl/resctrl_val.c create mode 100644 tools/testing/selftests/resctrl/resctrlfs.c -- 2.19.1

5 years, 7 months

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[PATCH v5 00/12] mm/gup: track FOLL_PIN pages

by John Hubbard

Hi, Here's another update after another round of reviews from Kirill and Jan. There is a git repo and branch, for convenience in reviewing: git@github.com:johnhubbard/linux.git track_user_pages_v5 ============================================================ Changes since v4: * Added documentation about the huge page behavior of the new /proc/vmstat items. * Added a missing mode_node_page_state() call to put_compound_head(). * Fixed a tracepoint call in page_ref_sub_return(). * Added a trailing underscore to a URL in pin_user_pages.rst, to fix a broken generated link. * Added ACKs and reviewed-by's from Jan Kara and Kirill Shutemov. * Rebased onto today's linux.git, and * I am experimenting here with "git format-patch --base=<commit>". This generated the "base-commit:" tag you'll see at the end of this cover letter. I was inspired to do so after trying out a new get-lore-mbox.py tool (it's very nice), mentioned in a recent LWN article (https://lwn.net/Articles/811528/ ). That tool relies on the base-commit tag for some things. ============================================================ Changes since v3: * Rebased onto latest linux.git * Added ACKs and reviewed-by's from Kirill Shutemov and Jan Kara. * /proc/vmstat: * Renamed items, after realizing that I hate the previous names: nr_foll_pin_requested --> nr_foll_pin_acquired nr_foll_pin_returned --> nr_foll_pin_released * Removed the CONFIG_DEBUG_VM guard, and collapsed away a wrapper routine: now just calls mod_node_page_state() directly. * Tweaked the WARN_ON_ONCE() statements in mm/hugetlb.c to be more informative, and added comments above them as well. * Fixed gup_benchmark: signed int --> unsigned long. * One or two minor formatting changes. ============================================================ Changes since v2: * Rebased onto linux.git, because the akpm tree for 5.6 has been merged. * Split the tracking patch into even more patches, as requested. * Merged Matthew Wilcox's dump_page() changes into mine, as part of the first patch. * Renamed: page_dma_pinned() --> page_maybe_dma_pinned(), in response to Kirill Shutemov's review. * Moved a WARN to the top of a routine, and fixed a typo in the commit description of patch #7, also as suggested by Kirill. ============================================================ Changes since v1: * Split the tracking patch into 6 smaller patches * Rebased onto today's linux-next/akpm (there weren't any conflicts). * Fixed an "unsigned int" vs. "int" problem in gup_benchmark, reported by Nathan Chancellor. (I don't see it in my local builds, probably because they use gcc, but an LLVM test found the mismatch.) * Fixed a huge page pincount problem (add/subtract vs. increment/decrement), spotted by Jan Kara. ============================================================ There is a reasonable case to be made for merging two of the patches (patches 7 and 8), given that patch 7 provides tracking that has upper limits on the number of pins that can be done with huge pages. Let me know if anyone wants those merged, but unless there is some weird chance of someone grabbing patch 7 and not patch 8, I don't really see the need. Meanwhile, it's easier to review in this form. Also, patch 3 has been revived. Earlier reviewers asked for it to be merged into the tracking patch (one cannot please everyone, heh), but now it's back out on it's own. This activates tracking of FOLL_PIN pages. This is in support of fixing the get_user_pages()+DMA problem described in [1]-[4]. FOLL_PIN support is now in the main linux tree. However, the patch to use FOLL_PIN to track pages was *not* submitted, because Leon saw an RDMA test suite failure that involved (I think) page refcount overflows when huge pages were used. This patch definitively solves that kind of overflow problem, by adding an exact pincount, for compound pages (of order > 1), in the 3rd struct page of a compound page. If available, that form of pincounting is used, instead of the GUP_PIN_COUNTING_BIAS approach. Thanks again to Jan Kara for that idea. Other interesting changes: * dump_page(): added one, or two new things to report for compound pages: head refcount (for all compound pages), and map_pincount (for compound pages of order > 1). * Documentation/core-api/pin_user_pages.rst: removed the "TODO" for the huge page refcount upper limit problems, and added notes about how it works now. Also added a note about the dump_page() enhancements. * Added some comments in gup.c and mm.h, to explain that there are two ways to count pinned pages: exact (for compound pages of order > 1) and fuzzy (GUP_PIN_COUNTING_BIAS: for all other pages). ============================================================ General notes about the tracking patch: This is a prerequisite to solving the problem of proper interactions between file-backed pages, and [R]DMA activities, as discussed in [1], [2], [3], [4] and in a remarkable number of email threads since about 2017. :) In contrast to earlier approaches, the page tracking can be incrementally applied to the kernel call sites that, until now, have been simply calling get_user_pages() ("gup"). In other words, opt-in by changing from this: get_user_pages() (sets FOLL_GET) put_page() to this: pin_user_pages() (sets FOLL_PIN) unpin_user_page() ============================================================ Next steps: * Convert more subsystems from get_user_pages() to pin_user_pages(). * Work with Ira and others to connect this all up with file system leases. [1] Some slow progress on get_user_pages() (Apr 2, 2019): https://lwn.net/Articles/784574/ [2] DMA and get_user_pages() (LPC: Dec 12, 2018): https://lwn.net/Articles/774411/ [3] The trouble with get_user_pages() (Apr 30, 2018): https://lwn.net/Articles/753027/ [4] LWN kernel index: get_user_pages() https://lwn.net/Kernel/Index/#Memory_management-get_user_pages John Hubbard (12): mm: dump_page(): better diagnostics for compound pages mm/gup: split get_user_pages_remote() into two routines mm/gup: pass a flags arg to __gup_device_* functions mm: introduce page_ref_sub_return() mm/gup: pass gup flags to two more routines mm/gup: require FOLL_GET for get_user_pages_fast() mm/gup: track FOLL_PIN pages mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages mm: dump_page(): better diagnostics for huge pinned pages mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting mm/gup_benchmark: support pin_user_pages() and related calls selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage Documentation/core-api/pin_user_pages.rst | 86 ++-- include/linux/mm.h | 108 ++++- include/linux/mm_types.h | 7 +- include/linux/mmzone.h | 2 + include/linux/page_ref.h | 9 + mm/debug.c | 61 ++- mm/gup.c | 452 ++++++++++++++++----- mm/gup_benchmark.c | 71 +++- mm/huge_memory.c | 29 +- mm/hugetlb.c | 60 ++- mm/page_alloc.c | 2 + mm/rmap.c | 6 + mm/vmstat.c | 2 + tools/testing/selftests/vm/gup_benchmark.c | 15 +- tools/testing/selftests/vm/run_vmtests | 22 + 15 files changed, 752 insertions(+), 180 deletions(-) base-commit: 90568ecf561540fa330511e21fcd823b0c3829c6 -- 2.25.0

5 years, 7 months

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Re: linux-5.6-rc1/tools/testing/selftests/bpf/prog_tests/select_reuseport.cc :826: possible cut-n-paste error ?

by Martin KaFai Lau

On Mon, Feb 10, 2020 at 01:42:45PM +0000, David Binderman wrote: > Hello there, > > saved_tcp_fo = read_int_sysctl(TCP_FO_SYSCTL); > saved_tcp_syncookie = read_int_sysctl(TCP_SYNCOOKIE_SYSCTL); > if (saved_tcp_syncookie < 0 || saved_tcp_syncookie < 0) > goto out; > > Maybe better code > > saved_tcp_fo = read_int_sysctl(TCP_FO_SYSCTL); > saved_tcp_syncookie = read_int_sysctl(TCP_SYNCOOKIE_SYSCTL); > if (saved_tcp_fo < 0 || saved_tcp_syncookie < 0) Thanks for the report. I will post a fix.

5 years, 7 months

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[PATCH v26 20/22] selftests/x86: Add vDSO selftest for SGX

by Jarkko Sakkinen

Expand the selftest by invoking the enclave by using __vdso_sgx_enter_enclave() in addition to direct ENCLS[EENTER]. Cc: linux-kselftest(a)vger.kernel.org Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen(a)linux.intel.com> --- tools/testing/selftests/x86/sgx/main.c | 132 +++++++++++++++++++++ tools/testing/selftests/x86/sgx/sgx_call.S | 43 +++++++ tools/testing/selftests/x86/sgx/sgx_call.h | 3 + 3 files changed, 178 insertions(+) diff --git a/tools/testing/selftests/x86/sgx/main.c b/tools/testing/selftests/x86/sgx/main.c index 48ed5fdfb3cb..d97cc3cf0093 100644 --- a/tools/testing/selftests/x86/sgx/main.c +++ b/tools/testing/selftests/x86/sgx/main.c @@ -21,6 +21,109 @@ #define PAGE_SIZE 4096 static const uint64_t MAGIC = 0x1122334455667788ULL; +void *eenter; + +struct vdso_symtab { + Elf64_Sym *elf_symtab; + const char *elf_symstrtab; + Elf64_Word *elf_hashtab; +}; + +static void *vdso_get_base_addr(char *envp[]) +{ + Elf64_auxv_t *auxv; + int i; + + for (i = 0; envp[i]; i++) + ; + + auxv = (Elf64_auxv_t *)&envp[i + 1]; + + for (i = 0; auxv[i].a_type != AT_NULL; i++) { + if (auxv[i].a_type == AT_SYSINFO_EHDR) + return (void *)auxv[i].a_un.a_val; + } + + return NULL; +} + +static Elf64_Dyn *vdso_get_dyntab(void *addr) +{ + Elf64_Ehdr *ehdr = addr; + Elf64_Phdr *phdrtab = addr + ehdr->e_phoff; + int i; + + for (i = 0; i < ehdr->e_phnum; i++) + if (phdrtab[i].p_type == PT_DYNAMIC) + return addr + phdrtab[i].p_offset; + + return NULL; +} + +static void *vdso_get_dyn(void *addr, Elf64_Dyn *dyntab, Elf64_Sxword tag) +{ + int i; + + for (i = 0; dyntab[i].d_tag != DT_NULL; i++) + if (dyntab[i].d_tag == tag) + return addr + dyntab[i].d_un.d_ptr; + + return NULL; +} + +static bool vdso_get_symtab(void *addr, struct vdso_symtab *symtab) +{ + Elf64_Dyn *dyntab = vdso_get_dyntab(addr); + + symtab->elf_symtab = vdso_get_dyn(addr, dyntab, DT_SYMTAB); + if (!symtab->elf_symtab) + return false; + + symtab->elf_symstrtab = vdso_get_dyn(addr, dyntab, DT_STRTAB); + if (!symtab->elf_symstrtab) + return false; + + symtab->elf_hashtab = vdso_get_dyn(addr, dyntab, DT_HASH); + if (!symtab->elf_hashtab) + return false; + + return true; +} + +static unsigned long elf_sym_hash(const char *name) +{ + unsigned long h = 0, high; + + while (*name) { + h = (h << 4) + *name++; + high = h & 0xf0000000; + + if (high) + h ^= high >> 24; + + h &= ~high; + } + + return h; +} + +static Elf64_Sym *vdso_symtab_get(struct vdso_symtab *symtab, const char *name) +{ + Elf64_Word bucketnum = symtab->elf_hashtab[0]; + Elf64_Word *buckettab = &symtab->elf_hashtab[2]; + Elf64_Word *chaintab = &symtab->elf_hashtab[2 + bucketnum]; + Elf64_Sym *sym; + Elf64_Word i; + + for (i = buckettab[elf_sym_hash(name) % bucketnum]; i != STN_UNDEF; + i = chaintab[i]) { + sym = &symtab->elf_symtab[i]; + if (!strcmp(name, &symtab->elf_symstrtab[sym->st_name])) + return sym; + } + + return NULL; +} static bool encl_create(int dev_fd, unsigned long bin_size, struct sgx_secs *secs) @@ -218,10 +321,14 @@ bool load_sigstruct(const char *path, void *sigstruct) int main(int argc, char *argv[], char *envp[]) { + struct sgx_enclave_exception exception; struct sgx_sigstruct sigstruct; + struct vdso_symtab symtab; + Elf64_Sym *eenter_sym; struct sgx_secs secs; uint64_t result = 0; off_t bin_size; + void *addr; void *bin; if (!encl_data_map("encl.bin", &bin, &bin_size)) @@ -243,5 +350,30 @@ int main(int argc, char *argv[], char *envp[]) printf("Output: 0x%lx\n", result); + memset(&exception, 0, sizeof(exception)); + + addr = vdso_get_base_addr(envp); + if (!addr) + exit(1); + + if (!vdso_get_symtab(addr, &symtab)) + exit(1); + + eenter_sym = vdso_symtab_get(&symtab, "__vdso_sgx_enter_enclave"); + if (!eenter_sym) + exit(1); + eenter = addr + eenter_sym->st_value; + + printf("Input: 0x%lx\n", MAGIC); + + sgx_call_vdso((void *)&MAGIC, &result, 0, NULL, NULL, NULL, + (void *)secs.base, &exception, NULL); + if (result != MAGIC) { + fprintf(stderr, "0x%lx != 0x%lx\n", result, MAGIC); + exit(1); + } + + printf("Output: 0x%lx\n", result); + exit(0); } diff --git a/tools/testing/selftests/x86/sgx/sgx_call.S b/tools/testing/selftests/x86/sgx/sgx_call.S index ca4c7893f9d9..e71f44f7a995 100644 --- a/tools/testing/selftests/x86/sgx/sgx_call.S +++ b/tools/testing/selftests/x86/sgx/sgx_call.S @@ -21,3 +21,46 @@ sgx_async_exit: ENCLU pop %rbx ret + + .global sgx_call_vdso +sgx_call_vdso: + .cfi_startproc + push %r15 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r15, 0 + push %r14 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r14, 0 + push %r13 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r13, 0 + push %r12 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r12, 0 + push %rbx + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %rbx, 0 + push $0 + .cfi_adjust_cfa_offset 8 + push 0x48(%rsp) + .cfi_adjust_cfa_offset 8 + push 0x48(%rsp) + .cfi_adjust_cfa_offset 8 + push 0x48(%rsp) + .cfi_adjust_cfa_offset 8 + mov $2, %eax + call *eenter(%rip) + add $0x20, %rsp + .cfi_adjust_cfa_offset -0x20 + pop %rbx + .cfi_adjust_cfa_offset -8 + pop %r12 + .cfi_adjust_cfa_offset -8 + pop %r13 + .cfi_adjust_cfa_offset -8 + pop %r14 + .cfi_adjust_cfa_offset -8 + pop %r15 + .cfi_adjust_cfa_offset -8 + ret + .cfi_endproc diff --git a/tools/testing/selftests/x86/sgx/sgx_call.h b/tools/testing/selftests/x86/sgx/sgx_call.h index bf72068ada23..a4072c5ecce7 100644 --- a/tools/testing/selftests/x86/sgx/sgx_call.h +++ b/tools/testing/selftests/x86/sgx/sgx_call.h @@ -8,4 +8,7 @@ void sgx_call_eenter(void *rdi, void *rsi, void *entry); +int sgx_call_vdso(void *rdi, void *rsi, long rdx, void *rcx, void *r8, void *r9, + void *tcs, struct sgx_enclave_exception *ei, void *cb); + #endif /* SGX_CALL_H */ -- 2.20.1

5 years, 7 months

1
0
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[PATCH v26 12/22] selftests/x86: Add a selftest for SGX

by Jarkko Sakkinen

Add a selftest for SGX. It is a trivial test where a simple enclave copies one 64-bit word of memory between two memory locations given to the enclave as arguments. Use ENCLS[EENTER] to invoke the enclave. Cc: linux-sgx(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen(a)linux.intel.com> --- tools/testing/selftests/x86/sgx/.gitignore | 3 + tools/testing/selftests/x86/sgx/Makefile | 48 ++ tools/testing/selftests/x86/sgx/defines.h | 17 + tools/testing/selftests/x86/sgx/encl.c | 20 + tools/testing/selftests/x86/sgx/encl.lds | 34 ++ .../selftests/x86/sgx/encl_bootstrap.S | 94 ++++ tools/testing/selftests/x86/sgx/main.c | 247 +++++++++ tools/testing/selftests/x86/sgx/sgx_call.S | 23 + tools/testing/selftests/x86/sgx/sgx_call.h | 11 + tools/testing/selftests/x86/sgx/sgxsign.c | 493 ++++++++++++++++++ .../testing/selftests/x86/sgx/signing_key.pem | 39 ++ 11 files changed, 1029 insertions(+) create mode 100644 tools/testing/selftests/x86/sgx/.gitignore create mode 100644 tools/testing/selftests/x86/sgx/Makefile create mode 100644 tools/testing/selftests/x86/sgx/defines.h create mode 100644 tools/testing/selftests/x86/sgx/encl.c create mode 100644 tools/testing/selftests/x86/sgx/encl.lds create mode 100644 tools/testing/selftests/x86/sgx/encl_bootstrap.S create mode 100644 tools/testing/selftests/x86/sgx/main.c create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.S create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.h create mode 100644 tools/testing/selftests/x86/sgx/sgxsign.c create mode 100644 tools/testing/selftests/x86/sgx/signing_key.pem diff --git a/tools/testing/selftests/x86/sgx/.gitignore b/tools/testing/selftests/x86/sgx/.gitignore new file mode 100644 index 000000000000..98eb2d439606 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/.gitignore @@ -0,0 +1,3 @@ +encl.ss +sgxsign +test_sgx diff --git a/tools/testing/selftests/x86/sgx/Makefile b/tools/testing/selftests/x86/sgx/Makefile new file mode 100644 index 000000000000..f838700029e2 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/Makefile @@ -0,0 +1,48 @@ +top_srcdir = ../../../../.. + +include ../../lib.mk + +ifndef OBJCOPY +OBJCOPY := $(CROSS_COMPILE)objcopy +endif + +INCLUDES := -I$(top_srcdir)/tools/include +HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC -z noexecstack +ENCL_CFLAGS := -Wall -Werror -static -nostdlib -nostartfiles -fPIC \ + -fno-stack-protector -mrdrnd $(INCLUDES) + +TEST_CUSTOM_PROGS := $(OUTPUT)/test_sgx $(OUTPUT)/encl.bin $(OUTPUT)/encl.ss + +all: $(TEST_CUSTOM_PROGS) + +$(OUTPUT)/test_sgx: $(OUTPUT)/main.o $(OUTPUT)/sgx_call.o + $(CC) $(HOST_CFLAGS) -o $@ $^ + +$(OUTPUT)/main.o: main.c + $(CC) $(HOST_CFLAGS) -c $< -o $@ + +$(OUTPUT)/sgx_call.o: sgx_call.S + $(CC) $(HOST_CFLAGS) -c $< -o $@ + +$(OUTPUT)/encl.bin: $(OUTPUT)/encl.elf $(OUTPUT)/sgxsign + $(OBJCOPY) -O binary $< $@ + +$(OUTPUT)/encl.elf: encl.lds encl.c encl_bootstrap.S + $(CC) $(ENCL_CFLAGS) -T $^ -o $@ + +$(OUTPUT)/encl.ss: $(OUTPUT)/encl.bin + $(OUTPUT)/sgxsign signing_key.pem $(OUTPUT)/encl.bin $(OUTPUT)/encl.ss + +$(OUTPUT)/sgxsign: sgxsign.c + $(CC) $(INCLUDES) -o $@ $< -lcrypto + +EXTRA_CLEAN := \ + $(OUTPUT)/encl.bin \ + $(OUTPUT)/encl.elf \ + $(OUTPUT)/encl.ss \ + $(OUTPUT)/sgx_call.o \ + $(OUTPUT)/sgxsign \ + $(OUTPUT)/test_sgx \ + $(OUTPUT)/test_sgx.o \ + +.PHONY: clean diff --git a/tools/testing/selftests/x86/sgx/defines.h b/tools/testing/selftests/x86/sgx/defines.h new file mode 100644 index 000000000000..87264f85cb9f --- /dev/null +++ b/tools/testing/selftests/x86/sgx/defines.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright(c) 2016-19 Intel Corporation. + */ + +#ifndef DEFINES_H +#define DEFINES_H + +#include <stdint.h> + +#define __aligned(x) __attribute__((__aligned__(x))) +#define __packed __attribute__((packed)) + +#include "../../../../../arch/x86/kernel/cpu/sgx/arch.h" +#include "../../../../../arch/x86/include/uapi/asm/sgx.h" + +#endif /* DEFINES_H */ diff --git a/tools/testing/selftests/x86/sgx/encl.c b/tools/testing/selftests/x86/sgx/encl.c new file mode 100644 index 000000000000..ede915399742 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/encl.c @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +// Copyright(c) 2016-18 Intel Corporation. + +#include <stddef.h> +#include "defines.h" + +static void *memcpy(void *dest, const void *src, size_t n) +{ + size_t i; + + for (i = 0; i < n; i++) + ((char *)dest)[i] = ((char *)src)[i]; + + return dest; +} + +void encl_body(void *rdi, void *rsi) +{ + memcpy(rsi, rdi, 8); +} diff --git a/tools/testing/selftests/x86/sgx/encl.lds b/tools/testing/selftests/x86/sgx/encl.lds new file mode 100644 index 000000000000..9a56d3064104 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/encl.lds @@ -0,0 +1,34 @@ +OUTPUT_FORMAT(elf64-x86-64) + +SECTIONS +{ + . = 0; + .tcs : { + *(.tcs*) + } + + . = ALIGN(4096); + .text : { + *(.text*) + *(.rodata*) + } + + . = ALIGN(4096); + .data : { + *(.data*) + } + + /DISCARD/ : { + *(.data*) + *(.comment*) + *(.note*) + *(.debug*) + *(.eh_frame*) + } +} + +ASSERT(!DEFINED(.altinstructions), "ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.altinstr_replacement), "ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.discard.retpoline_safe), "RETPOLINE ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.discard.nospec), "RETPOLINE ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.got.plt), "Libcalls are not supported in enclaves") diff --git a/tools/testing/selftests/x86/sgx/encl_bootstrap.S b/tools/testing/selftests/x86/sgx/encl_bootstrap.S new file mode 100644 index 000000000000..d07f970ccdf9 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/encl_bootstrap.S @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */ +/* + * Copyright(c) 2016-18 Intel Corporation. + */ + + .macro ENCLU + .byte 0x0f, 0x01, 0xd7 + .endm + + .section ".tcs", "a" + .balign 4096 + + .fill 1, 8, 0 # STATE (set by CPU) + .fill 1, 8, 0 # FLAGS + .quad encl_ssa # OSSA + .fill 1, 4, 0 # CSSA (set by CPU) + .fill 1, 4, 1 # NSSA + .quad encl_entry # OENTRY + .fill 1, 8, 0 # AEP (set by EENTER and ERESUME) + .fill 1, 8, 0 # OFSBASE + .fill 1, 8, 0 # OGSBASE + .fill 1, 4, 0xFFFFFFFF # FSLIMIT + .fill 1, 4, 0xFFFFFFFF # GSLIMIT + .fill 4024, 1, 0 # Reserved + + .text + +encl_entry: + # RBX contains the base address for TCS, which is also the first address + # inside the enclave. By adding the value of le_stack_end to it, we get + # the absolute address for the stack. + lea (encl_stack)(%rbx), %rax + xchg %rsp, %rax + push %rax + + push %rcx # push the address after EENTER + push %rbx # push the enclave base address + + call encl_body + + pop %rbx # pop the enclave base address + + # Restore XSAVE registers to a synthetic state. + mov $0xFFFFFFFF, %rax + mov $0xFFFFFFFF, %rdx + lea (xsave_area)(%rbx), %rdi + fxrstor (%rdi) + + # Clear GPRs. + xor %rcx, %rcx + xor %rdx, %rdx + xor %rdi, %rdi + xor %rsi, %rsi + xor %r8, %r8 + xor %r9, %r9 + xor %r10, %r10 + xor %r11, %r11 + xor %r12, %r12 + xor %r13, %r13 + xor %r14, %r14 + xor %r15, %r15 + + # Reset status flags. + add %rdx, %rdx # OF = SF = AF = CF = 0; ZF = PF = 1 + + # Prepare EEXIT target by popping the address of the instruction after + # EENTER to RBX. + pop %rbx + + # Restore the caller stack. + pop %rax + mov %rax, %rsp + + # EEXIT + mov $4, %rax + enclu + + .section ".data", "aw" + +encl_ssa: + .space 4096 + +xsave_area: + .fill 1, 4, 0x037F # FCW + .fill 5, 4, 0 + .fill 1, 4, 0x1F80 # MXCSR + .fill 1, 4, 0xFFFF # MXCSR_MASK + .fill 123, 4, 0 + .fill 1, 4, 0x80000000 # XCOMP_BV[63] = 1, compaction mode + .fill 12, 4, 0 + + .balign 4096 + .space 8192 +encl_stack: diff --git a/tools/testing/selftests/x86/sgx/main.c b/tools/testing/selftests/x86/sgx/main.c new file mode 100644 index 000000000000..48ed5fdfb3cb --- /dev/null +++ b/tools/testing/selftests/x86/sgx/main.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +// Copyright(c) 2016-18 Intel Corporation. + +#include <elf.h> +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <sys/types.h> +#include "defines.h" +#include "sgx_call.h" + +#define PAGE_SIZE 4096 + +static const uint64_t MAGIC = 0x1122334455667788ULL; + +static bool encl_create(int dev_fd, unsigned long bin_size, + struct sgx_secs *secs) +{ + struct sgx_enclave_create ioc; + void *area; + int rc; + + memset(secs, 0, sizeof(*secs)); + secs->ssa_frame_size = 1; + secs->attributes = SGX_ATTR_MODE64BIT; + secs->xfrm = 3; + + for (secs->size = 4096; secs->size < bin_size; ) + secs->size <<= 1; + + area = mmap(NULL, secs->size * 2, PROT_NONE, MAP_SHARED, dev_fd, 0); + if (area == MAP_FAILED) { + perror("mmap"); + return false; + } + + secs->base = ((uint64_t)area + secs->size - 1) & ~(secs->size - 1); + + munmap(area, secs->base - (uint64_t)area); + munmap((void *)(secs->base + secs->size), + (uint64_t)area + secs->size - secs->base); + + ioc.src = (unsigned long)secs; + rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_CREATE, &ioc); + if (rc) { + fprintf(stderr, "ECREATE failed rc=%d, err=%d.\n", rc, errno); + munmap((void *)secs->base, secs->size); + return false; + } + + return true; +} + +static bool encl_add_pages(int dev_fd, unsigned long offset, void *data, + unsigned long length, uint64_t flags) +{ + struct sgx_enclave_add_pages ioc; + struct sgx_secinfo secinfo; + int rc; + + memset(&secinfo, 0, sizeof(secinfo)); + secinfo.flags = flags; + + ioc.src = (uint64_t)data; + ioc.offset = offset; + ioc.length = length; + ioc.secinfo = (unsigned long)&secinfo; + ioc.flags = SGX_PAGE_MEASURE; + + rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_ADD_PAGES, &ioc); + if (rc) { + fprintf(stderr, "EADD failed rc=%d.\n", rc); + return false; + } + + if (ioc.count != ioc.length) { + fprintf(stderr, "Partially processed, update the test.\n"); + return false; + } + + return true; +} + +#define SGX_REG_PAGE_FLAGS \ + (SGX_SECINFO_REG | SGX_SECINFO_R | SGX_SECINFO_W | SGX_SECINFO_X) + +static bool encl_build(struct sgx_secs *secs, void *bin, + unsigned long bin_size, struct sgx_sigstruct *sigstruct) +{ + struct sgx_enclave_init ioc; + void *addr; + int dev_fd; + int rc; + + dev_fd = open("/dev/sgx/enclave", O_RDWR); + if (dev_fd < 0) { + fprintf(stderr, "Unable to open /dev/sgx\n"); + return false; + } + + if (!encl_create(dev_fd, bin_size, secs)) + goto out_dev_fd; + + if (!encl_add_pages(dev_fd, 0, bin, PAGE_SIZE, SGX_SECINFO_TCS)) + goto out_dev_fd; + + if (!encl_add_pages(dev_fd, PAGE_SIZE, bin + PAGE_SIZE, + bin_size - PAGE_SIZE, SGX_REG_PAGE_FLAGS)) + goto out_dev_fd; + + ioc.sigstruct = (uint64_t)sigstruct; + rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_INIT, &ioc); + if (rc) { + printf("EINIT failed rc=%d\n", rc); + goto out_map; + } + + addr = mmap((void *)secs->base, PAGE_SIZE, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_FIXED, dev_fd, 0); + if (addr == MAP_FAILED) { + fprintf(stderr, "mmap() failed on TCS, errno=%d.\n", errno); + return false; + } + + addr = mmap((void *)(secs->base + PAGE_SIZE), bin_size - PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_SHARED | MAP_FIXED, dev_fd, 0); + if (addr == MAP_FAILED) { + fprintf(stderr, "mmap() failed, errno=%d.\n", errno); + return false; + } + + close(dev_fd); + return true; +out_map: + munmap((void *)secs->base, secs->size); +out_dev_fd: + close(dev_fd); + return false; +} + +bool get_file_size(const char *path, off_t *bin_size) +{ + struct stat sb; + int ret; + + ret = stat(path, &sb); + if (ret) { + perror("stat"); + return false; + } + + if (!sb.st_size || sb.st_size & 0xfff) { + fprintf(stderr, "Invalid blob size %lu\n", sb.st_size); + return false; + } + + *bin_size = sb.st_size; + return true; +} + +bool encl_data_map(const char *path, void **bin, off_t *bin_size) +{ + int fd; + + fd = open(path, O_RDONLY); + if (fd == -1) { + fprintf(stderr, "open() %s failed, errno=%d.\n", path, errno); + return false; + } + + if (!get_file_size(path, bin_size)) + goto err_out; + + *bin = mmap(NULL, *bin_size, PROT_READ, MAP_PRIVATE, fd, 0); + if (*bin == MAP_FAILED) { + fprintf(stderr, "mmap() %s failed, errno=%d.\n", path, errno); + goto err_out; + } + + close(fd); + return true; + +err_out: + close(fd); + return false; +} + +bool load_sigstruct(const char *path, void *sigstruct) +{ + int fd; + + fd = open(path, O_RDONLY); + if (fd == -1) { + fprintf(stderr, "open() %s failed, errno=%d.\n", path, errno); + return false; + } + + if (read(fd, sigstruct, sizeof(struct sgx_sigstruct)) != + sizeof(struct sgx_sigstruct)) { + fprintf(stderr, "read() %s failed, errno=%d.\n", path, errno); + close(fd); + return false; + } + + close(fd); + return true; +} + +int main(int argc, char *argv[], char *envp[]) +{ + struct sgx_sigstruct sigstruct; + struct sgx_secs secs; + uint64_t result = 0; + off_t bin_size; + void *bin; + + if (!encl_data_map("encl.bin", &bin, &bin_size)) + exit(1); + + if (!load_sigstruct("encl.ss", &sigstruct)) + exit(1); + + if (!encl_build(&secs, bin, bin_size, &sigstruct)) + exit(1); + + printf("Input: 0x%lx\n", MAGIC); + + sgx_call_eenter((void *)&MAGIC, &result, (void *)secs.base); + if (result != MAGIC) { + fprintf(stderr, "0x%lx != 0x%lx\n", result, MAGIC); + exit(1); + } + + printf("Output: 0x%lx\n", result); + + exit(0); +} diff --git a/tools/testing/selftests/x86/sgx/sgx_call.S b/tools/testing/selftests/x86/sgx/sgx_call.S new file mode 100644 index 000000000000..ca4c7893f9d9 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/sgx_call.S @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */ +/** +* Copyright(c) 2016-18 Intel Corporation. +*/ + + .text + + .macro ENCLU + .byte 0x0f, 0x01, 0xd7 + .endm + + .text + + .global sgx_call_eenter +sgx_call_eenter: + push %rbx + mov $0x02, %rax + mov %rdx, %rbx + lea sgx_async_exit(%rip), %rcx +sgx_async_exit: + ENCLU + pop %rbx + ret diff --git a/tools/testing/selftests/x86/sgx/sgx_call.h b/tools/testing/selftests/x86/sgx/sgx_call.h new file mode 100644 index 000000000000..bf72068ada23 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/sgx_call.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright(c) 2016-19 Intel Corporation. + */ + +#ifndef SGX_CALL_H +#define SGX_CALL_H + +void sgx_call_eenter(void *rdi, void *rsi, void *entry); + +#endif /* SGX_CALL_H */ diff --git a/tools/testing/selftests/x86/sgx/sgxsign.c b/tools/testing/selftests/x86/sgx/sgxsign.c new file mode 100644 index 000000000000..3d9007af40c9 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/sgxsign.c @@ -0,0 +1,493 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +// Copyright(c) 2016-18 Intel Corporation. + +#define _GNU_SOURCE +#include <getopt.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> +#include <openssl/err.h> +#include <openssl/pem.h> +#include "defines.h" + +struct sgx_sigstruct_payload { + struct sgx_sigstruct_header header; + struct sgx_sigstruct_body body; +}; + +static bool check_crypto_errors(void) +{ + int err; + bool had_errors = false; + const char *filename; + int line; + char str[256]; + + for ( ; ; ) { + if (ERR_peek_error() == 0) + break; + + had_errors = true; + err = ERR_get_error_line(&filename, &line); + ERR_error_string_n(err, str, sizeof(str)); + fprintf(stderr, "crypto: %s: %s:%d\n", str, filename, line); + } + + return had_errors; +} + +static void exit_usage(const char *program) +{ + fprintf(stderr, + "Usage: %s/sign-le <key> <enclave> <sigstruct>\n", program); + exit(1); +} + +static inline const BIGNUM *get_modulus(RSA *key) +{ +#if OPENSSL_VERSION_NUMBER < 0x10100000L + return key->n; +#else + const BIGNUM *n; + + RSA_get0_key(key, &n, NULL, NULL); + return n; +#endif +} + +static RSA *load_sign_key(const char *path) +{ + FILE *f; + RSA *key; + + f = fopen(path, "rb"); + if (!f) { + fprintf(stderr, "Unable to open %s\n", path); + return NULL; + } + key = RSA_new(); + if (!PEM_read_RSAPrivateKey(f, &key, NULL, NULL)) + return NULL; + fclose(f); + + if (BN_num_bytes(get_modulus(key)) != SGX_MODULUS_SIZE) { + fprintf(stderr, "Invalid key size %d\n", + BN_num_bytes(get_modulus(key))); + RSA_free(key); + return NULL; + } + + return key; +} + +static void reverse_bytes(void *data, int length) +{ + int i = 0; + int j = length - 1; + uint8_t temp; + uint8_t *ptr = data; + + while (i < j) { + temp = ptr[i]; + ptr[i] = ptr[j]; + ptr[j] = temp; + i++; + j--; + } +} + +enum mrtags { + MRECREATE = 0x0045544145524345, + MREADD = 0x0000000044444145, + MREEXTEND = 0x00444E4554584545, +}; + +static bool mrenclave_update(EVP_MD_CTX *ctx, const void *data) +{ + if (!EVP_DigestUpdate(ctx, data, 64)) { + fprintf(stderr, "digest update failed\n"); + return false; + } + + return true; +} + +static bool mrenclave_commit(EVP_MD_CTX *ctx, uint8_t *mrenclave) +{ + unsigned int size; + + if (!EVP_DigestFinal_ex(ctx, (unsigned char *)mrenclave, &size)) { + fprintf(stderr, "digest commit failed\n"); + return false; + } + + if (size != 32) { + fprintf(stderr, "invalid digest size = %u\n", size); + return false; + } + + return true; +} + +struct mrecreate { + uint64_t tag; + uint32_t ssaframesize; + uint64_t size; + uint8_t reserved[44]; +} __attribute__((__packed__)); + + +static bool mrenclave_ecreate(EVP_MD_CTX *ctx, uint64_t blob_size) +{ + struct mrecreate mrecreate; + uint64_t encl_size; + + for (encl_size = 0x1000; encl_size < blob_size; ) + encl_size <<= 1; + + memset(&mrecreate, 0, sizeof(mrecreate)); + mrecreate.tag = MRECREATE; + mrecreate.ssaframesize = 1; + mrecreate.size = encl_size; + + if (!EVP_DigestInit_ex(ctx, EVP_sha256(), NULL)) + return false; + + return mrenclave_update(ctx, &mrecreate); +} + +struct mreadd { + uint64_t tag; + uint64_t offset; + uint64_t flags; /* SECINFO flags */ + uint8_t reserved[40]; +} __attribute__((__packed__)); + +static bool mrenclave_eadd(EVP_MD_CTX *ctx, uint64_t offset, uint64_t flags) +{ + struct mreadd mreadd; + + memset(&mreadd, 0, sizeof(mreadd)); + mreadd.tag = MREADD; + mreadd.offset = offset; + mreadd.flags = flags; + + return mrenclave_update(ctx, &mreadd); +} + +struct mreextend { + uint64_t tag; + uint64_t offset; + uint8_t reserved[48]; +} __attribute__((__packed__)); + +static bool mrenclave_eextend(EVP_MD_CTX *ctx, uint64_t offset, uint8_t *data) +{ + struct mreextend mreextend; + int i; + + for (i = 0; i < 0x1000; i += 0x100) { + memset(&mreextend, 0, sizeof(mreextend)); + mreextend.tag = MREEXTEND; + mreextend.offset = offset + i; + + if (!mrenclave_update(ctx, &mreextend)) + return false; + + if (!mrenclave_update(ctx, &data[i + 0x00])) + return false; + + if (!mrenclave_update(ctx, &data[i + 0x40])) + return false; + + if (!mrenclave_update(ctx, &data[i + 0x80])) + return false; + + if (!mrenclave_update(ctx, &data[i + 0xC0])) + return false; + } + + return true; +} + +/** + * measure_encl - measure enclave + * @path: path to the enclave + * @mrenclave: measurement + * + * Calculates MRENCLAVE. Assumes that the very first page is a TCS page and + * following pages are regular pages. Does not measure the contents of the + * enclave as the signing tool is used at the moment only for the launch + * enclave, which is pass-through (everything gets a token). + */ +static bool measure_encl(const char *path, uint8_t *mrenclave) +{ + FILE *file; + struct stat sb; + EVP_MD_CTX *ctx; + uint64_t flags; + uint64_t offset; + uint8_t data[0x1000]; + int rc; + + ctx = EVP_MD_CTX_create(); + if (!ctx) + return false; + + file = fopen(path, "rb"); + if (!file) { + perror("fopen"); + EVP_MD_CTX_destroy(ctx); + return false; + } + + rc = stat(path, &sb); + if (rc) { + perror("stat"); + goto out; + } + + if (!sb.st_size || sb.st_size & 0xfff) { + fprintf(stderr, "Invalid blob size %lu\n", sb.st_size); + goto out; + } + + if (!mrenclave_ecreate(ctx, sb.st_size)) + goto out; + + for (offset = 0; offset < sb.st_size; offset += 0x1000) { + if (!offset) + flags = SGX_SECINFO_TCS; + else + flags = SGX_SECINFO_REG | SGX_SECINFO_R | + SGX_SECINFO_W | SGX_SECINFO_X; + + if (!mrenclave_eadd(ctx, offset, flags)) + goto out; + + rc = fread(data, 1, 0x1000, file); + if (!rc) + break; + if (rc < 0x1000) + goto out; + + if (!mrenclave_eextend(ctx, offset, data)) + goto out; + } + + if (!mrenclave_commit(ctx, mrenclave)) + goto out; + + fclose(file); + EVP_MD_CTX_destroy(ctx); + return true; +out: + fclose(file); + EVP_MD_CTX_destroy(ctx); + return false; +} + +/** + * sign_encl - sign enclave + * @sigstruct: pointer to SIGSTRUCT + * @key: 3072-bit RSA key + * @signature: byte array for the signature + * + * Calculates EMSA-PKCSv1.5 signature for the given SIGSTRUCT. The result is + * stored in big-endian format so that it can be further passed to OpenSSL + * libcrypto functions. + */ +static bool sign_encl(const struct sgx_sigstruct *sigstruct, RSA *key, + uint8_t *signature) +{ + struct sgx_sigstruct_payload payload; + unsigned int siglen; + uint8_t digest[SHA256_DIGEST_LENGTH]; + bool ret; + + memcpy(&payload.header, &sigstruct->header, sizeof(sigstruct->header)); + memcpy(&payload.body, &sigstruct->body, sizeof(sigstruct->body)); + + SHA256((unsigned char *)&payload, sizeof(payload), digest); + + ret = RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH, signature, + &siglen, key); + + return ret; +} + +struct q1q2_ctx { + BN_CTX *bn_ctx; + BIGNUM *m; + BIGNUM *s; + BIGNUM *q1; + BIGNUM *qr; + BIGNUM *q2; +}; + +static void free_q1q2_ctx(struct q1q2_ctx *ctx) +{ + BN_CTX_free(ctx->bn_ctx); + BN_free(ctx->m); + BN_free(ctx->s); + BN_free(ctx->q1); + BN_free(ctx->qr); + BN_free(ctx->q2); +} + +static bool alloc_q1q2_ctx(const uint8_t *s, const uint8_t *m, + struct q1q2_ctx *ctx) +{ + ctx->bn_ctx = BN_CTX_new(); + ctx->s = BN_bin2bn(s, SGX_MODULUS_SIZE, NULL); + ctx->m = BN_bin2bn(m, SGX_MODULUS_SIZE, NULL); + ctx->q1 = BN_new(); + ctx->qr = BN_new(); + ctx->q2 = BN_new(); + + if (!ctx->bn_ctx || !ctx->s || !ctx->m || !ctx->q1 || !ctx->qr || + !ctx->q2) { + free_q1q2_ctx(ctx); + return false; + } + + return true; +} + +static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1, + uint8_t *q2) +{ + struct q1q2_ctx ctx; + + if (!alloc_q1q2_ctx(s, m, &ctx)) { + fprintf(stderr, "Not enough memory for Q1Q2 calculation\n"); + return false; + } + + if (!BN_mul(ctx.q1, ctx.s, ctx.s, ctx.bn_ctx)) + goto out; + + if (!BN_div(ctx.q1, ctx.qr, ctx.q1, ctx.m, ctx.bn_ctx)) + goto out; + + if (BN_num_bytes(ctx.q1) > SGX_MODULUS_SIZE) { + fprintf(stderr, "Too large Q1 %d bytes\n", + BN_num_bytes(ctx.q1)); + goto out; + } + + if (!BN_mul(ctx.q2, ctx.s, ctx.qr, ctx.bn_ctx)) + goto out; + + if (!BN_div(ctx.q2, NULL, ctx.q2, ctx.m, ctx.bn_ctx)) + goto out; + + if (BN_num_bytes(ctx.q2) > SGX_MODULUS_SIZE) { + fprintf(stderr, "Too large Q2 %d bytes\n", + BN_num_bytes(ctx.q2)); + goto out; + } + + BN_bn2bin(ctx.q1, q1); + BN_bn2bin(ctx.q2, q2); + + free_q1q2_ctx(&ctx); + return true; +out: + free_q1q2_ctx(&ctx); + return false; +} + +static bool save_sigstruct(const struct sgx_sigstruct *sigstruct, + const char *path) +{ + FILE *f = fopen(path, "wb"); + + if (!f) { + fprintf(stderr, "Unable to open %s\n", path); + return false; + } + + fwrite(sigstruct, sizeof(*sigstruct), 1, f); + fclose(f); + return true; +} + +int main(int argc, char **argv) +{ + uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000}; + uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060}; + struct sgx_sigstruct ss; + const char *program; + int opt; + RSA *sign_key; + + memset(&ss, 0, sizeof(ss)); + ss.header.header1[0] = header1[0]; + ss.header.header1[1] = header1[1]; + ss.header.header2[0] = header2[0]; + ss.header.header2[1] = header2[1]; + ss.exponent = 3; + +#ifndef CONFIG_EINITTOKENKEY + ss.body.attributes = SGX_ATTR_MODE64BIT; +#else + ss.body.attributes = SGX_ATTR_MODE64BIT | SGX_ATTR_EINITTOKENKEY; +#endif + ss.body.xfrm = 3, + + program = argv[0]; + + do { + opt = getopt(argc, argv, ""); + switch (opt) { + case -1: + break; + default: + exit_usage(program); + } + } while (opt != -1); + + argc -= optind; + argv += optind; + + if (argc < 3) + exit_usage(program); + + /* sanity check only */ + if (check_crypto_errors()) + exit(1); + + sign_key = load_sign_key(argv[0]); + if (!sign_key) + goto out; + + BN_bn2bin(get_modulus(sign_key), ss.modulus); + + if (!measure_encl(argv[1], ss.body.mrenclave)) + goto out; + + if (!sign_encl(&ss, sign_key, ss.signature)) + goto out; + + if (!calc_q1q2(ss.signature, ss.modulus, ss.q1, ss.q2)) + goto out; + + /* convert to little endian */ + reverse_bytes(ss.signature, SGX_MODULUS_SIZE); + reverse_bytes(ss.modulus, SGX_MODULUS_SIZE); + reverse_bytes(ss.q1, SGX_MODULUS_SIZE); + reverse_bytes(ss.q2, SGX_MODULUS_SIZE); + + if (!save_sigstruct(&ss, argv[2])) + goto out; + exit(0); +out: + check_crypto_errors(); + exit(1); +} diff --git a/tools/testing/selftests/x86/sgx/signing_key.pem b/tools/testing/selftests/x86/sgx/signing_key.pem new file mode 100644 index 000000000000..d76f21f19187 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/signing_key.pem @@ -0,0 +1,39 @@ +-----BEGIN RSA PRIVATE KEY----- +MIIG4wIBAAKCAYEApalGbq7Q+usM91CPtksu3D+b0Prc8gAFL6grM3mg85A5Bx8V +cfMXPgtrw8EYFwQxDAvzZWwl+9VfOX0ECrFRBkOHcOiG0SnADN8+FLj1UiNUQwbp +S6OzhNWuRcSbGraSOyUlVlV0yMQSvewyzGklOaXBe30AJqzIBc8QfdSxKuP8rs0Z +ga6k/Bl73osrYKByILJTUUeZqjLERsE6GebsdzbWgKn8qVqng4ZS4yMNg6LeRlH3 ++9CIPgg4jwpSLHcp7dq2qTIB9a0tGe9ayp+5FbucpB6U7ePold0EeRN6RlJGDF9k +L93v8P5ykz5G5gYZ2g0K1X2sHIWV4huxPgv5PXgdyQYbK+6olqj0d5rjYuwX57Ul +k6SroPS1U6UbdCjG5txM+BNGU0VpD0ZhrIRw0leQdnNcCO9sTJuInZrgYacSVJ7u +mtB+uCt+uzUesc+l+xPRYA+9e14lLkZp7AAmo9FvL816XDI09deehJ3i/LmHKCRN +tuqC5TprRjFwUr6dAgEDAoIBgG5w2Z8fNfycs0+LCnmHdJLVEotR6KFVWMpwHMz7 +wKJgJgS/Y6FMuilc8oKAuroCy11dTO5IGVKOP3uorVx2NgQtBPXwWeDGgAiU1A3Q +o4wXjYIEm4fCd63jyYPYZ2ckYXzDbjmOTdstYdPyzIhGGNEZK6eoqsRzMAPfYFPj +IMdCqHSIu6vJw1K7p+myHOsVoWshjODaZnF3LYSA0WaZ8vokjwBxUxuRxQJZjJds +s60XPtmL+qfgWtQFewoG4XL6GuD8FcXccynRRtzrLtFNPIl9BQfWfjBBhTC1/Te1 +0Z6XbZvpdUTD9OfLB7SbR2OUFNpKQgriO0iYVdbW3cr7uu38Zwp4W1TX73DPjoi6 +KNooP6SGWd4mRJW2+dUmSYS4QNG8eVVZswKcploEIXlAKRsOe4kzJJ1iETugIe85 +uX8nd1WYEp65xwoRUg8hqng0MeyveVbXqNKuJG6tzNDt9kgFYo+hmC/oouAW2Dtc +T9jdRAwKJXqA2Eg6OkgXCEv+kwKBwQDYaQiFMlFhsmLlqI+EzCUh7c941/cL7m6U +7j98+8ngl0HgCEcrc10iJVCKakQW3YbPzAx3XkKTaGjWazvvrFarXIGlOud64B8a +iWyQ7VdlnmZnNEdk+C83tI91OQeaTKqRLDGzKh29Ry/jL8Pcbazt+kDgxa0H7qJp +roADUanLQuNkYubpbhFBh3xpa2EExaVq6rF7nIVsD8W9TrbmPKA4LgH7z0iy544D +kVCNYsTjYDdUWP+WiSor8kCnnpjnN9sCgcEAw/eNezUD1UDf6OYFC9+5JZJFn4Tg +mZMyN93JKIb199ffwnjtHUSjcyiWeesXucpzwtGbTcwQnDisSW4oneYKLSEBlBaq +scqiUugyGZZOthFSCbdXYXMViK2vHrKlkse7GxVlROKcEhM/pRBrmjaGO8eWR+D4 +FO2wCXzVs3KgV6j779frw0vC54oHOxc9+Lu1rSHp4i+600koyvL/zF6U/5tZXIvN +YW2yoiQJnjCmVA1pwbwV6KAUTPDTMnBK+YjnAoHBAJBGBa4hi5Z27JkbCliIGMFJ +NPs6pLKe9GNJf6in2+sPgUAFhMeiPhbDiwbxgrnpBIqICE+ULGJFmzmc0p/IOceT +ARjR76dAFLxbnbXzj5kURETNhO36yiUjCk4mBRGIcbYddndxaSjaH+zKgpLzyJ6m +1esuc1qfFvEfAAI2cTIsl5hB70ZJYNZaUvDyQK3ZGPHxy6e9rkgKg9OJz0QoatAe +q/002yHvtAJg4F5B2JeVejg7VQ8GHB1MKxppu0TP5wKBwQCCpQj8zgKOKz/wmViy +lSYZDC5qWJW7t3bP6TDFr06lOpUsUJ4TgxeiGw778g/RMaKB4RIz3WBoJcgw9BsT +7rFza1ZiucchMcGMmswRDt8kC4wGejpA92Owc8oUdxkMhSdnY5jYlxK2t3/DYEe8 +JFl9L7mFQKVjSSAGUzkiTGrlG1Kf5UfXh9dFBq98uilQfSPIwUaWynyM23CHTKqI +Pw3/vOY9sojrnncWwrEUIG7is5vWfWPwargzSzd29YdRBe8CgcEAuRVewK/YeNOX +B7ZG6gKKsfsvrGtY7FPETzLZAHjoVXYNea4LVZ2kn4hBXXlvw/4HD+YqcTt4wmif +5JQlDvjNobUiKJZpzy7hklVhF7wZFl4pCF7Yh43q9iQ7gKTaeUG7MiaK+G8Zz8aY +HW9rsiihbdZkccMvnPfO9334XMxl3HtBRzLstjUlbLB7Sdh+7tZ3JQidCOFNs5pE +XyWwnASPu4tKfDahH1UUTp1uJcq/6716CSWg080avYxFcn75qqsb +-----END RSA PRIVATE KEY----- -- 2.20.1

5 years, 7 months

1
0
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[PATCH v2 0/4] Implement FUTEX_WAIT_MULTIPLE operation

by André Almeida

Hello, This patchset implements a new futex operation, called FUTEX_WAIT_MULTIPLE, which allows a thread to wait on several futexes at the same time, and be awoken by any of them. The use case lies in the Wine implementation of the Windows NT interface WaitMultipleObjects. This Windows API function allows a thread to sleep waiting on the first of a set of event sources (mutexes, timers, signal, console input, etc) to signal. Considering this is a primitive synchronization operation for Windows applications, being able to quickly signal events on the producer side, and quickly go to sleep on the consumer side is essential for good performance of those running over Wine. Since this API exposes a mechanism to wait on multiple objects, and we might have multiple waiters for each of these events, a M->N relationship, the current Linux interfaces fell short on performance evaluation of large M,N scenarios. We experimented, for instance, with eventfd, which has performance problems discussed below, but we also experimented with userspace solutions, like making each consumer wait on a condition variable guarding the entire list of objects, and then waking up multiple variables on the producer side, but this is prohibitively expensive since we either need to signal many condition variables or share that condition variable among multiple waiters, and then verify for the event being signaled in userspace, which means dealing with often false positive wakes ups. The natural interface to implement the behavior we want, also considering that one of the waitable objects is a mutex itself, would be the futex interface. Therefore, this patchset proposes a mechanism for a thread to wait on multiple futexes at once, and wake up on the first futex that was awaken. In particular, using futexes in our Wine use case reduced the CPU utilization by 4% for the game Beat Saber and by 1.5% for the game Shadow of Tomb Raider, both running over Proton (a Wine based solution for Windows emulation), when compared to the eventfd interface. This implementation also doesn't rely of file descriptors, so it doesn't risk overflowing the resource. In time, we are also proposing modifications to glibc and libpthread to make this feature available for Linux native multithreaded applications using libpthread, which can benefit from the behavior of waiting on any of a group of futexes. Technically, the existing FUTEX_WAIT implementation can be easily reworked by using futex_wait_multiple() with a count of one, and I have a patch showing how it works. I'm not proposing it, since futex is such a tricky code, that I'd be more comfortable to have FUTEX_WAIT_MULTIPLE running upstream for a couple development cycles, before considering modifying FUTEX_WAIT. The patch series includes an extensive set of kselftests validating the behavior of the interface. We also implemented support[1] on Syzkaller and survived the fuzzy testing. Finally, if you'd rather pull directly a branch with this set you can find it here: https://gitlab.collabora.com/tonyk/linux/commits/futex-dev === Performance of eventfd === Polling on several eventfd contexts with semaphore semantics would provide us with the exact semantics we are looking for. However, as shown below, in a scenario with sufficient producers and consumers, the eventfd interface itself becomes a bottleneck, in particular because each thread will compete to acquire a sequence of waitqueue locks for each eventfd context in the poll list. In addition, in the uncontended case, where the producer is ready for consumption, eventfd still requires going into the kernel on the consumer side. When a write or a read operation in an eventfd file succeeds, it will try to wake up all threads that are waiting to perform some operation to the file. The lock (ctx->wqh.lock) that hold the access to the file value (ctx->count) is the same lock used to control access the waitqueue. When all those those thread woke, they will compete to get this lock. Along with that, the poll() also manipulates the waitqueue and need to hold this same lock. This lock is specially hard to acquire when poll() calls poll_freewait(), where it tries to free all waitqueues associated with this poll. While doing that, it will compete with a lot of read and write operations that have been waken. In our use case, with a huge number of parallel reads, writes and polls, this lock is a bottleneck and hurts the performance of applications. Our implementation of futex, however, decrease the calls of spin lock by more than 80% in some user applications. Finally, eventfd operates on file descriptors, which is a limited resource that has shown its limitation in our use cases. Despite the Windows interface not waiting on more than 64 objects at once, we still have multiple waiters at the same time, and we were easily able to exhaust the FD limits on applications like games. The RFC for this patch can be found here: https://lkml.org/lkml/2019/7/30/1399 Thanks, André [1] https://github.com/andrealmeid/syzkaller/tree/futex-wait-multiple Gabriel Krisman Bertazi (4): futex: Implement mechanism to wait on any of several futexes selftests: futex: Add FUTEX_WAIT_MULTIPLE timeout test selftests: futex: Add FUTEX_WAIT_MULTIPLE wouldblock test selftests: futex: Add FUTEX_WAIT_MULTIPLE wake up test include/uapi/linux/futex.h | 20 + kernel/futex.c | 356 +++++++++++++++++- .../selftests/futex/functional/.gitignore | 1 + .../selftests/futex/functional/Makefile | 3 +- .../futex/functional/futex_wait_multiple.c | 173 +++++++++ .../futex/functional/futex_wait_timeout.c | 38 +- .../futex/functional/futex_wait_wouldblock.c | 28 +- .../testing/selftests/futex/functional/run.sh | 3 + .../selftests/futex/include/futextest.h | 22 + 9 files changed, 635 insertions(+), 7 deletions(-) create mode 100644 tools/testing/selftests/futex/functional/futex_wait_multiple.c -- 2.25.0

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