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by Noreply＠lists.linaro.org

5 years, 1 month

[PATCHv2 0/4] perf/core: Add support to exclude kernel mode PMU tracing

by Sai Prakash Ranjan

Hardware assisted tracing families such as ARM Coresight, Intel PT provides rich tracing capabilities including instruction level tracing and accurate timestamps which are very useful for profiling and also pose a significant security risk. One such example of security risk is when kernel mode tracing is not excluded and these hardware assisted tracing can be used to analyze cryptographic code execution. In this case, even the root user must not be able to infer anything. To explain it more clearly in the words of a security team member (credits: Mattias Nissler), "Consider a system where disk contents are encrypted and the encryption key is set up by the user when mounting the file system. From that point on the encryption key resides in the kernel. It seems reasonable to expect that the disk encryption key be protected from exfiltration even if the system later suffers a root compromise (or even against insiders that have root access), at least as long as the attacker doesn't manage to compromise the kernel." Here the idea is to protect such important information from all users including root users since root privileges does not have to mean full control over the kernel [1] and root compromise does not have to be the end of the world. But "Peter said even the regular counters can be used for full branch trace, the information isn't as accurate as PT and friends and not easier but is good enough to infer plenty". This would mean that a global tunable config for all kernel mode pmu tracing is more appropriate than the one targeting the hardware assisted instruction tracing. Currently we can exclude kernel mode tracing via perf_event_paranoid sysctl but it has following limitations, * No option to restrict kernel mode instruction tracing by the root user. * Not possible to restrict kernel mode instruction tracing when the hardware assisted tracing IPs like ARM Coresight ETMs use an additional interface via sysfs for tracing in addition to perf interface. So introduce a new config CONFIG_EXCLUDE_KERNEL_PMU_TRACE to exclude kernel mode pmu tracing for all users including root which will be generic and applicable to all hardware tracing families and which can also be used with other interfaces like sysfs in case of ETMs. Patch 1 adds this new config and the support in perf core to exclude all kernel mode PMU tracing. Patch 2 adds the perf evsel warning message when the perf tool users attempt to perform a kernel mode trace with the config enabled to exclude the kernel mode tracing. Patch 3 and Patch 4 adds the support for excluding kernel mode for ARM Coresight ETM{4,3}XX sysfs mode using the newly introduced generic config. [1] https://lwn.net/Articles/796866/ Changes in v2: * Move from kernel mode instruction tracing to all kernel level PMU tracing (Peter) * Move the check and warning to the caller mode_store() (Doug) Sai Prakash Ranjan (4): perf/core: Add support to exclude kernel mode PMU tracing perf evsel: Print warning for excluding kernel mode instruction tracing coresight: etm4x: Add support to exclude kernel mode tracing coresight: etm3x: Add support to exclude kernel mode tracing drivers/hwtracing/coresight/coresight-etm3x-core.c | 3 +++ drivers/hwtracing/coresight/coresight-etm3x-sysfs.c | 6 ++++++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 6 +++++- drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 6 ++++++ init/Kconfig | 11 +++++++++++ kernel/events/core.c | 3 +++ tools/perf/util/evsel.c | 3 ++- 7 files changed, 36 insertions(+), 2 deletions(-) -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

5 years, 1 month

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5 years, 1 month

[PATCH v2 0/8] perf: Refine barriers for AUX ring buffer

by Leo Yan

Based on the discussion [1], this patch series is to refine the memory barriers for AUX ring buffer. Patches 01 ~ 04 to address the barriers usage in the kernel. The first patch is to make clear comment for how to use the barriers between the data store and aux_head store, this asks the driver to make sure the data is visible. Patches 02 ~ 04 is to refine the drivers for barriers after the data store. Patches 05 ~ 07 is to fix and clean up the memory barries in perf tool for AUX ring buffer. Since the 64-bit value's atomicity is not promised on 32-bit perf, the last patch is to report error and let perf to directly exit for this case. Have testes the patches on Arm64 Juno platform. [1] https://lore.kernel.org/patchwork/patch/1431867/ Leo Yan (8): perf/ring_buffer: Add comment for barriers on AUX ring buffer coresight: tmc-etr: Add barrier after updating AUX ring buffer coresight: tmc-etf: Add comment for store ordering perf/x86: Add barrier after updating bts perf auxtrace: Change to use SMP memory barriers perf auxtrace: Drop legacy __sync functions perf auxtrace: Use WRITE_ONCE() for updating aux_tail perf record: Directly bail out for compat case arch/x86/events/intel/bts.c | 3 +++ .../hwtracing/coresight/coresight-tmc-etf.c | 6 +++++ .../hwtracing/coresight/coresight-tmc-etr.c | 8 ++++++ kernel/events/ring_buffer.c | 9 +++++++ tools/perf/builtin-record.c | 17 ++++++++++++ tools/perf/util/auxtrace.h | 27 +++---------------- 6 files changed, 47 insertions(+), 23 deletions(-) -- 2.25.1

5 years, 1 month

From Nasser Rashid

by Nasser Rashid

5 years, 1 month

#Invitation to Bid

by Albert Bourla

5 years, 1 month

my future investment ventures in your country

by Ms. Kim

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5 years, 1 month

[RFC PATCH v4 0/1] perf cs-etm: Split Coresight decode by aux records

by James Clark

Changes since v3: * Include fix for snapshot mode * Fix typo that was in the initial snapshot fix posted to the previous thread (&& -> &) James Clark (1): perf cs-etm: Split Coresight decode by aux records tools/perf/util/cs-etm.c | 159 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 156 insertions(+), 3 deletions(-) -- 2.28.0

5 years, 1 month

From Nasser

by Nasser Rashid

5 years, 1 month

[PATCH 00/34] docs: avoid using ReST :doc:`foo` tag

by Mauro Carvalho Chehab

As discussed at: https://lore.kernel.org/linux-doc/871r9k6rmy.fsf@meer.lwn.net/ It is better to avoid using :doc:`foo` to refer to Documentation/foo.rst, as the automarkup.py extension should handle it automatically, on most cases. There are a couple of exceptions to this rule: 1. when :doc: tag is used to point to a kernel-doc DOC: markup; 2. when it is used with a named tag, e. g. :doc:`some name <foo>`; It should also be noticed that automarkup.py has currently an issue: if one use a markup like: Documentation/dev-tools/kunit/api/test.rst - documents all of the standard testing API excluding mocking or mocking related features. or, even: Documentation/dev-tools/kunit/api/test.rst documents all of the standard testing API excluding mocking or mocking related features. The automarkup.py will simply ignore it. Not sure why. This patch series avoid the above patterns (which is present only on 4 files), but it would be nice to have a followup patch fixing the issue at automarkup.py. On this series: Patch 1 manually adjust the references inside driver-api/pm/devices.rst, as there it uses :file:`foo` to refer to some Documentation/ files; Patch 2 converts a table at Documentation/dev-tools/kunit/api/index.rst into a list, carefully avoiding the Patch 3 converts the cross-references at the media documentation, also avoiding the automarkup.py bug; Patches 4-34 convert the other occurrences via a replace script. They were manually edited, in order to honour 80-columns where possible. I did a diff between the Sphinx 2.4.4 output before and after this patch series in order to double-check that all converted Documentation/ references will produce <a href=<foo>.rst>foo title</a> tags. Mauro Carvalho Chehab (34): docs: devices.rst: better reference documentation docs docs: dev-tools: kunit: don't use a table for docs name media: docs: */media/index.rst: don't use ReST doc:`foo` media: userspace-api: avoid using ReST :doc:`foo` markup media: driver-api: drivers: avoid using ReST :doc:`foo` markup media: admin-guide: avoid using ReST :doc:`foo` markup docs: admin-guide: pm: avoid using ReSt :doc:`foo` markup docs: admin-guide: hw-vuln: avoid using ReST :doc:`foo` markup docs: admin-guide: sysctl: avoid using ReST :doc:`foo` markup docs: block: biodoc.rst: avoid using ReSt :doc:`foo` markup docs: bpf: bpf_lsm.rst: avoid using ReSt :doc:`foo` markup docs: core-api: avoid using ReSt :doc:`foo` markup docs: dev-tools: testing-overview.rst: avoid using ReSt :doc:`foo` markup docs: dev-tools: kunit: avoid using ReST :doc:`foo` markup docs: devicetree: bindings: submitting-patches.rst: avoid using ReSt :doc:`foo` markup docs: doc-guide: avoid using ReSt :doc:`foo` markup docs: driver-api: avoid using ReSt :doc:`foo` markup docs: driver-api: gpio: using-gpio.rst: avoid using ReSt :doc:`foo` markup docs: driver-api: surface_aggregator: avoid using ReSt :doc:`foo` markup docs: driver-api: usb: avoid using ReSt :doc:`foo` markup docs: firmware-guide: acpi: avoid using ReSt :doc:`foo` markup docs: hwmon: adm1177.rst: avoid using ReSt :doc:`foo` markup docs: i2c: avoid using ReSt :doc:`foo` markup docs: kernel-hacking: hacking.rst: avoid using ReSt :doc:`foo` markup docs: networking: devlink: avoid using ReSt :doc:`foo` markup docs: PCI: endpoint: pci-endpoint-cfs.rst: avoid using ReSt :doc:`foo` markup docs: PCI: pci.rst: avoid using ReSt :doc:`foo` markup docs: process: submitting-patches.rst: avoid using ReSt :doc:`foo` markup docs: security: landlock.rst: avoid using ReSt :doc:`foo` markup docs: trace: coresight: coresight.rst: avoid using ReSt :doc:`foo` markup docs: trace: ftrace.rst: avoid using ReSt :doc:`foo` markup docs: userspace-api: landlock.rst: avoid using ReSt :doc:`foo` markup docs: virt: kvm: s390-pv-boot.rst: avoid using ReSt :doc:`foo` markup docs: x86: avoid using ReSt :doc:`foo` markup .../PCI/endpoint/pci-endpoint-cfs.rst | 2 +- Documentation/PCI/pci.rst | 6 +-- .../special-register-buffer-data-sampling.rst | 3 +- Documentation/admin-guide/media/bt8xx.rst | 15 ++++---- Documentation/admin-guide/media/bttv.rst | 21 ++++++----- Documentation/admin-guide/media/index.rst | 12 +++--- Documentation/admin-guide/media/saa7134.rst | 3 +- Documentation/admin-guide/pm/intel_idle.rst | 16 +++++--- Documentation/admin-guide/pm/intel_pstate.rst | 9 +++-- Documentation/admin-guide/sysctl/abi.rst | 2 +- Documentation/admin-guide/sysctl/kernel.rst | 37 ++++++++++--------- Documentation/block/biodoc.rst | 2 +- Documentation/bpf/bpf_lsm.rst | 13 ++++--- .../core-api/bus-virt-phys-mapping.rst | 2 +- Documentation/core-api/dma-api.rst | 5 ++- Documentation/core-api/dma-isa-lpc.rst | 2 +- Documentation/core-api/index.rst | 4 +- Documentation/dev-tools/kunit/api/index.rst | 8 ++-- Documentation/dev-tools/kunit/faq.rst | 2 +- Documentation/dev-tools/kunit/index.rst | 14 +++---- Documentation/dev-tools/kunit/start.rst | 6 +-- Documentation/dev-tools/kunit/tips.rst | 5 ++- Documentation/dev-tools/kunit/usage.rst | 8 ++-- Documentation/dev-tools/testing-overview.rst | 16 ++++---- .../bindings/submitting-patches.rst | 11 +++--- Documentation/doc-guide/contributing.rst | 8 ++-- Documentation/driver-api/gpio/using-gpio.rst | 4 +- Documentation/driver-api/ioctl.rst | 2 +- .../driver-api/media/drivers/bttv-devel.rst | 2 +- Documentation/driver-api/media/index.rst | 10 +++-- Documentation/driver-api/pm/devices.rst | 8 ++-- .../surface_aggregator/clients/index.rst | 3 +- .../surface_aggregator/internal.rst | 15 ++++---- .../surface_aggregator/overview.rst | 6 ++- Documentation/driver-api/usb/dma.rst | 6 +-- .../acpi/dsd/data-node-references.rst | 3 +- .../firmware-guide/acpi/dsd/graph.rst | 2 +- .../firmware-guide/acpi/enumeration.rst | 7 ++-- Documentation/hwmon/adm1177.rst | 3 +- Documentation/i2c/instantiating-devices.rst | 2 +- Documentation/i2c/old-module-parameters.rst | 3 +- Documentation/i2c/smbus-protocol.rst | 4 +- Documentation/kernel-hacking/hacking.rst | 4 +- .../networking/devlink/devlink-region.rst | 2 +- .../networking/devlink/devlink-trap.rst | 4 +- Documentation/process/submitting-patches.rst | 32 ++++++++-------- Documentation/security/landlock.rst | 3 +- Documentation/trace/coresight/coresight.rst | 8 ++-- Documentation/trace/ftrace.rst | 2 +- Documentation/userspace-api/landlock.rst | 11 +++--- .../userspace-api/media/glossary.rst | 2 +- Documentation/userspace-api/media/index.rst | 12 +++--- Documentation/virt/kvm/s390-pv-boot.rst | 2 +- Documentation/x86/boot.rst | 4 +- Documentation/x86/mtrr.rst | 2 +- 55 files changed, 217 insertions(+), 183 deletions(-) -- 2.31.1

5 years, 1 month

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