tjh.dev
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Pull more perf tools updates from Arnaldo Carvalho de Melo:
- Avoid SEGV if core.cpus isn't set in 'perf stat'.
- Stop depending on .git files for building PERF-VERSION-FILE, used in
'perf --version', fixing some perf tools build scenarios.
- Convert tracepoint.py example to python3.
- Update UAPI header copies from the kernel sources: socket,
mman-common, msr-index, KVM, i915 and cpufeatures.
- Update copy of libbpf's hashmap.c.
- Directly return instead of using local ret variable in
evlist__create_syswide_maps(), found by coccinelle.
* tag 'perf-tools-for-v5.18-2022-04-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
perf python: Convert tracepoint.py example to python3
perf evlist: Directly return instead of using local ret variable
perf cpumap: More cpu map reuse by merge.
perf cpumap: Add is_subset function
perf evlist: Rename cpus to user_requested_cpus
perf tools: Stop depending on .git files for building PERF-VERSION-FILE
tools headers cpufeatures: Sync with the kernel sources
tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
tools headers UAPI: Sync linux/kvm.h with the kernel sources
tools kvm headers arm64: Update KVM headers from the kernel sources
tools arch x86: Sync the msr-index.h copy with the kernel sources
tools headers UAPI: Sync asm-generic/mman-common.h with the kernel
perf beauty: Update copy of linux/socket.h with the kernel sources
perf tools: Update copy of libbpf's hashmap.c
perf stat: Avoid SEGV if core.cpus isn't set
Pull Kbuild fixes from Masahiro Yamada:
- Fix empty $(PYTHON) expansion.
- Fix UML, which got broken by the attempt to suppress Clang warnings.
- Fix warning message in modpost.
* tag 'kbuild-fixes-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
modpost: restore the warning message for missing symbol versions
Revert "um: clang: Strip out -mno-global-merge from USER_CFLAGS"
kbuild: Remove '-mno-global-merge'
kbuild: fix empty ${PYTHON} in scripts/link-vmlinux.sh
kconfig: remove stale comment about removed kconfig_print_symbol()
Convert the tracepoint.py file to python3 as many of the files in
tools/perf are already written in python3.
Committer testing:
# export PYTHONPATH=/tmp/build/perf/python/
# python3 ~acme/git/perf/tools/perf/python/tracepoint.py | head
time 67394457376909 prev_comm=swapper/12 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=gnome-terminal- next_pid=3313 next_prio=120
time 67394457807669 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457811859 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457824929 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457831899 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457842299 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457844179 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457853879 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
time 67394457856339 prev_comm=swapper/13 prev_pid=0 prev_prio=120 prev_state=0x0 ==> next_comm=python3 next_pid=1485930 next_prio=120
time 67394457865659 prev_comm=python3 prev_pid=1485930 prev_prio=120 prev_state=0x1 ==> next_comm=swapper/13 next_pid=0 next_prio=120
Traceback (most recent call last):
File "/var/home/acme/git/perf/tools/perf/python/tracepoint.py", line 48, in <module>
main()
File "/var/home/acme/git/perf/tools/perf/python/tracepoint.py", line 37, in main
print("time %u prev_comm=%s prev_pid=%d prev_prio=%d prev_state=0x%x ==> next_comm=%s next_pid=%d next_prio=%d" % (
BrokenPipeError: [Errno 32] Broken pipe
#
Signed-off-by: Tanu M <tanu235m@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/linux-perf-users/CAPS78prawYzRZnyhWjgOnGw4EwoswNwztvfZFdCOPOydFzVwzQ@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull MIPS fixes from Thomas Bogendoerfer:
- build fix for gpio
- fix crc32 build problems
- check for failed memory allocations
* tag 'mips_5.18_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: crypto: Fix CRC32 code
MIPS: rb532: move GPIOD definition into C-files
MIPS: lantiq: check the return value of kzalloc()
mips: sgi-ip22: add a check for the return of kzalloc()
This log message was accidentally chopped off.
I was wondering why this happened, but checking the ML log, Mark
precisely followed my suggestion [1].
I just used "..." because I was too lazy to type the sentence fully.
Sorry for the confusion.
[1]: https://lore.kernel.org/all/CAK7LNAR6bXXk9-ZzZYpTqzFqdYbQsZHmiWspu27rtsFxvfRuVA@mail.gmail.com/
Fixes: 4a6795933a89 ("kbuild: modpost: Explicitly warn about unprototyped symbols")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Addresses this coccinelle warning:
./tools/perf/util/evlist.c:1333:5-8: Unneeded variable: "err". Return
"- ENOMEM" on line 1358
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/1648432532-23151-1-git-send-email-baihaowen@meizu.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull kvm fixes from Paolo Bonzini:
- Only do MSR filtering for MSRs accessed by rdmsr/wrmsr
- Documentation improvements
- Prevent module exit until all VMs are freed
- PMU Virtualization fixes
- Fix for kvm_irq_delivery_to_apic_fast() NULL-pointer dereferences
- Other miscellaneous bugfixes
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (42 commits)
KVM: x86: fix sending PV IPI
KVM: x86/mmu: do compare-and-exchange of gPTE via the user address
KVM: x86: Remove redundant vm_entry_controls_clearbit() call
KVM: x86: cleanup enter_rmode()
KVM: x86: SVM: fix tsc scaling when the host doesn't support it
kvm: x86: SVM: remove unused defines
KVM: x86: SVM: move tsc ratio definitions to svm.h
KVM: x86: SVM: fix avic spec based definitions again
KVM: MIPS: remove reference to trap&emulate virtualization
KVM: x86: document limitations of MSR filtering
KVM: x86: Only do MSR filtering when access MSR by rdmsr/wrmsr
KVM: x86/emulator: Emulate RDPID only if it is enabled in guest
KVM: x86/pmu: Fix and isolate TSX-specific performance event logic
KVM: x86: mmu: trace kvm_mmu_set_spte after the new SPTE was set
KVM: x86/svm: Clear reserved bits written to PerfEvtSeln MSRs
KVM: x86: Trace all APICv inhibit changes and capture overall status
KVM: x86: Add wrappers for setting/clearing APICv inhibits
KVM: x86: Make APICv inhibit reasons an enum and cleanup naming
KVM: X86: Handle implicit supervisor access with SMAP
KVM: X86: Rename variable smap to not_smap in permission_fault()
...
Commit 67512a8cf5a7 ("MIPS: Avoid macro redefinitions") changed how the
MIPS register macros were defined, in order to allow the code to compile
under LLVM/Clang.
The MIPS CRC32 code however wasn't updated accordingly, causing a build
bug when using a MIPS32r6 toolchain without CRC support.
Update the CRC32 code to use the macros correctly, to fix the build
failures.
Fixes: 67512a8cf5a7 ("MIPS: Avoid macro redefinitions")
Cc: <stable@vger.kernel.org>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This reverts commit 6580c5c18fb3df2b11c5e0452372f815deeff895.
This patch is buggy, as noted in the patch linked below. The root cause
has been solved by removing '-mno-global-merge' for the entire kernel.
Link: https://lore.kernel.org/r/20220322173547.677760-1-nathan@kernel.org/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
perf_cpu_map__merge() will reuse one of its arguments if they are equal or
the other argument is NULL.
The arguments could be reused if it is known one set of values is a
subset of the other.
For example, a map of 0-1 and a map of just 0 when merged yields the map
of 0-1.
Currently a new map is created rather than adding a reference count to
the original 0-1 map.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: German Gomez <german.gomez@arm.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: John Garry <john.garry@huawei.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220328232648.2127340-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull block driver fix from Jens Axboe:
"Got two reports on nbd spewing warnings on load now, which is a
regression from a commit that went into your tree yesterday.
Revert the problematic change for now"
* tag 'for-5.18/drivers-2022-04-02' of git://git.kernel.dk/linux-block:
Revert "nbd: fix possible overflow on 'first_minor' in nbd_dev_add()"
If apic_id is less than min, and (max - apic_id) is greater than
KVM_IPI_CLUSTER_SIZE, then the third check condition is satisfied but
the new apic_id does not fit the bitmask. In this case __send_ipi_mask
should send the IPI.
This is mostly theoretical, but it can happen if the apic_ids on three
iterations of the loop are for example 1, KVM_IPI_CLUSTER_SIZE, 0.
Fixes: aaffcfd1e82 ("KVM: X86: Implement PV IPIs in linux guest")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Message-Id: <1646814944-51801-1-git-send-email-lirongqing@baidu.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
My kernel robot reports build error from drivers/iio/adc/da9150-gpadc.c,
drivers/iio/adc/da9150-gpadc.c:254:13: error: ‘DA9150_GPADC_CHAN_0x08’
undeclared here (not in a function); did you mean ‘DA9150_GPADC_CHAN_TBAT’?
254 | .channel = DA9150_GPADC_CHAN_##_id,
We define GPIOD in rb.h, in fact it should only be used in gpio.c, but
it affects the driver da9150-gpadc.c which goes against the original
intention of the design, just move it to its scope.
Fixes: 1b432840d0a4 ("MIPS: RB532: GPIO register offsets are relative to GPIOBASE")
Suggested-by: Jonathan Cameron <jic23@kernel.org>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reported-by: k2ci <kernel-bot@kylinos.cn>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This flag is specific to clang, where it is only used by the 32-bit and
64-bit ARM backends. In certain situations, the presence of this flag
will cause a warning, as shown by commit 6580c5c18fb3 ("um: clang: Strip
out -mno-global-merge from USER_CFLAGS").
Since commit 61163efae020 ("kbuild: LLVMLinux: Add Kbuild support for
building kernel with Clang") that added this flag back in 2014, there
have been quite a few changes to the GlobalMerge pass in LLVM. Building
several different ARCH=arm and ARCH=arm64 configurations with LLVM 11
(minimum) and 15 (current main version) with this flag removed (i.e.,
with the default of '-mglobal-merge') reveals no modpost warnings, so it
is likely that the issue noted in the comment is no longer relevant due
to changes in LLVM or modpost, meaning this flag can be removed.
If any new warnings show up that are a result of the removal of this
flag, it can be added back under arch/arm{,64}/Makefile to avoid
warnings on other architectures.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: David Gow <davidgow@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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