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
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When booting a MacBookPro9,1, duplicate link downtraining messages are
logged for the devices directly attached to the two CPU-internal Root Ports
of the Core i7 3615QM: Once on device enumeration and once on enablement
of the bandwidth notification interrupt on the Root Ports.
Duplicate messages do not occur with Root Ports on the PCH and Downstream
Ports on the Thunderbolt controller: Only a single message is logged for
these, namely on device enumeration.
The reason for the duplicate messages is a stale interrupt in the Link
Status register of the 3615QM's internal Root Ports. Avoid by clearing the
interrupt before enabling it.
An alternative approach would be to clear the interrupt already on device
enumeration or to report link downtraining only if the speed has changed.
That way, link downtraining occurring between device enumeration and
enablement of the bandwidth notification interrupt could be caught.
However clearing stale interrupts before enabling them is a standard
operating procedure for any driver and keeping the two steps in one place
makes the code easier to follow.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alexandru Gagniuc <alex.gagniuc@dellteam.com>
A threaded IRQ with a NULL handler does not work with level-triggered
interrupts. request_threaded_irq() will return an error:
genirq: Threaded irq requested with handler=NULL and !ONESHOT for irq 16
pcie_bw_notification: probe of 0000:00:1b.0:pcie010 failed with error -22
For level interrupts we need to silence the interrupt before exiting the
IRQ handler, so just clear the PCI_EXP_LNKSTA_LBMS bit there.
Fixes: e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Pull more Kbuild updates from Masahiro Yamada:
- add more Build-Depends to Debian source package
- prefix header search paths with $(srctree)/
- make modpost show verbose section mismatch warnings
- avoid hard-coded CROSS_COMPILE for h8300
- fix regression for Debian make-kpkg command
- add semantic patch to detect missing put_device()
- fix some warnings of 'make deb-pkg'
- optimize NOSTDINC_FLAGS evaluation
- add warnings about redundant generic-y
- clean up Makefiles and scripts
* tag 'kbuild-v5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: remove stale lxdialog/.gitignore
kbuild: force all architectures except um to include mandatory-y
kbuild: warn redundant generic-y
Revert "modsign: Abort modules_install when signing fails"
kbuild: Make NOSTDINC_FLAGS a simply expanded variable
kbuild: deb-pkg: avoid implicit effects
coccinelle: semantic code search for missing put_device()
kbuild: pkg: grep include/config/auto.conf instead of $KCONFIG_CONFIG
kbuild: deb-pkg: introduce is_enabled and if_enabled_echo to builddeb
kbuild: deb-pkg: add CONFIG_ prefix to kernel config options
kbuild: add workaround for Debian make-kpkg
kbuild: source include/config/auto.conf instead of ${KCONFIG_CONFIG}
unicore32: simplify linker script generation for decompressor
h8300: use cc-cross-prefix instead of hardcoding h8300-unknown-linux-
kbuild: move archive command to scripts/Makefile.lib
modpost: always show verbose warning for section mismatch
ia64: prefix header search path with $(srctree)/
libfdt: prefix header search paths with $(srctree)/
deb-pkg: generate correct build dependencies
Pull x86 asm updates from Thomas Gleixner:
"Two cleanup patches removing dead conditionals and unused code"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/asm: Remove unused __constant_c_x_memset() macro and inlines
x86/asm: Remove dead __GNUC__ conditionals
When this .gitignore was added, lxdialog was an independent hostprogs-y.
Now that all objects in lxdialog/ are directly linked to mconf, the
lxdialog is no longer generated.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull perf fixes from Thomas Gleixner:
"Three fixes for the fallout from the TSX errata workaround:
- Prevent memory corruption caused by a unchecked out of bound array
index.
- Two trivial fixes to address compiler warnings"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Make dev_attr_allow_tsx_force_abort static
perf/x86: Fixup typo in stub functions
perf/x86/intel: Fix memory corruption
Nothing refers to the __constant_c_x_memset() macro anymore. Remove
it and the two referenced static inline functions.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190111084931.24601-2-linux@rasmusvillemoes.dk
Currently, every arch/*/include/uapi/asm/Kbuild explicitly includes
the common Kbuild.asm file. Factor out the duplicated include directives
to scripts/Makefile.asm-generic so that no architecture would opt out
of the mandatory-y mechanism.
um is not forced to include mandatory-y since it is a very exceptional
case which does not support UAPI.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull xen fix from Juergen Gross:
"A fix for a Xen bug introduced by David's series for excluding
ballooned pages in vmcores"
* tag 'for-linus-5.1b-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/balloon: Fix mapping PG_offline pages to user space
Fixes: 400816f60c54 ("perf/x86/intel: Implement support for TSX Force Abort")
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: kbuild-all@01.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190313184243.GA10820@lkp-sb-ep06
The minimum supported gcc version is >= 4.6, so these can be removed.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190111084931.24601-1-linux@rasmusvillemoes.dk
The generic-y is redundant under the following condition:
- arch has its own implementation
- the same header is added to generated-y
- the same header is added to mandatory-y
If a redundant generic-y is found, the warning like follows is displayed:
scripts/Makefile.asm-generic:20: redundant generic-y found in arch/arm/include/asm/Kbuild: timex.h
I fixed up arch Kbuild files found by this.
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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