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
1443962
3
927
Clone this repository
https://tangled.org/tjh.dev/kernel
https://tangled.org/did:plc:65gha4t3avpfpzmvpbwovss7/kernel
git@gordian.tjh.dev:tjh.dev/kernel
git@gordian.tjh.dev:did:plc:65gha4t3avpfpzmvpbwovss7/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
A microcode update on some Intel processors causes all TSX transactions
to always abort by default[*]. Microcode also added functionality to
re-enable TSX for development purposes. With this microcode loaded, if
tsx=on was passed on the cmdline, and TSX development mode was already
enabled before the kernel boot, it may make the system vulnerable to TSX
Asynchronous Abort (TAA).
To be on safer side, unconditionally disable TSX development mode during
boot. If a viable use case appears, this can be revisited later.
[*]: Intel TSX Disable Update for Selected Processors, doc ID: 643557
[ bp: Drop unstable web link, massage heavily. ]
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/347bd844da3a333a9793c6687d4e4eb3b2419a3e.1646943780.git.pawan.kumar.gupta@linux.intel.com
tsx_clear_cpuid() uses MSR_TSX_FORCE_ABORT to clear CPUID.RTM and
CPUID.HLE. Not all CPUs support MSR_TSX_FORCE_ABORT, alternatively use
MSR_IA32_TSX_CTRL when supported.
[ bp: Document how and why TSX gets disabled. ]
Fixes: 293649307ef9 ("x86/tsx: Clear CPUID bits when TSX always force aborts")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/5b323e77e251a9c8bcdda498c5cc0095be1e1d3c.1646943780.git.pawan.kumar.gupta@linux.intel.com
Pull serial driver fix from Greg KH:
"This is a single serial driver fix for a build issue that showed up
due to changes that came in through the tty tree in 5.18-rc1 that were
missed previously. It resolves a build error with the mpc52xx_uart
driver.
It has been in linux-next this week with no reported problems"
* tag 'tty-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
tty: serial: mpc52xx_uart: make rx/tx hooks return unsigned, part II.
Pull staging driver fix from Greg KH:
"Here is a single staging driver fix for 5.18-rc2 that resolves an
endian issue for the r8188eu driver. It has been in linux-next all
this week with no reported problems"
* tag 'staging-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: r8188eu: Fix PPPoE tag insertion on little endian systems
The below commit changed types of some hooks in struct psc_ops. It also
changed the types of the functions which are referenced in the instances
of the above struct.
However the commit did so only for CONFIG_PPC_MPC52xx, but not for
CONFIG_PPC_MPC512x. This results in build errors like:
mpc52xx_uart.c:static unsigned int mpc52xx_psc_raw_tx_rdy(struct uart_port *port)
mpc52xx_uart.c:static int mpc512x_psc_raw_tx_rdy(struct uart_port *port)
^^^
mpc52xx_uart.c:static int mpc5125_psc_raw_tx_rdy(struct uart_port *port)
^^^
Therefore, fix the latter case now too.
Fixes: 18662a1d8f35 (tty: serial: mpc52xx_uart: make rx/tx hooks return unsigned)
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220404055122.31194-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge tag 'driver-core-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here are two small driver core changes for 5.18-rc2.
They are the final bits in the removal of the default_attrs field in
struct kobj_type. I had to wait until after 5.18-rc1 for all of the
changes to do this came in through different development trees, and
then one new user snuck in. So this series has two changes:
- removal of the default_attrs field in the powerpc/pseries/vas code.
The change has been acked by the PPC maintainers to come through
this tree
- removal of default_attrs from struct kobj_type now that all
in-kernel users are removed.
This cleans up the kobject code a little bit and removes some
duplicated functionality that confused people (now there is only
one way to do default groups)
Both of these have been in linux-next for all of this week with no
reported problems"
* tag 'driver-core-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
kobject: kobj_type: remove default_attrs
powerpc/pseries/vas: use default_groups in kobj_type
In __nat25_add_pppoe_tag(), the tag length is read from the tag data
structure. The value is kept in network format, but read as raw value.
With -Warray-bounds, this results in the following gcc error/warning
when building the driver on alpha.
In function '__nat25_add_pppoe_tag',
inlined from 'nat25_db_handle' at
drivers/staging/r8188eu/core/rtw_br_ext.c:479:11:
arch/alpha/include/asm/string.h:22:16: error:
'__builtin_memcpy' forming offset [40, 2051] is out of the bounds
[0, 40] of object 'tag_buf' with type 'unsigned char[40]'
Add the missing be16_to_cpu() to fix the compile error. It should be
noted, however, that this fix means that the code did probably not work
on any little endian systems and/or that the driver has other endiannes
related issues. A build with C=1 suggests that this is indeed the case.
This patch does not attempt to fix any of those other issues.
Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")
Cc: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220404134338.3276991-1-linux@roeck-us.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull char/misc driver fix from Greg KH:
"A single driver fix. It resolves the build warning issue on 32bit
systems in the habannalabs driver that came in during the 5.18-rc1
merge cycle.
It has been in linux-next for all this week with no reported problems"
* tag 'char-misc-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
habanalabs: Fix test build failures
Now that all in-kernel users of default_attrs for the kobj_type are gone
and converted to properly use the default_groups pointer instead, it can
be safely removed.
There is one standard way to create sysfs files in a kobj_type, and not
two like before, causing confusion as to which should be used.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20220106133151.607703-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull more tracing updates from Steven Rostedt:
- Rename the staging files to give them some meaning. Just
stage1,stag2,etc, does not show what they are for
- Check for NULL from allocation in bootconfig
- Hold event mutex for dyn_event call in user events
- Mark user events to broken (to work on the API)
- Remove eBPF updates from user events
- Remove user events from uapi header to keep it from being installed.
- Move ftrace_graph_is_dead() into inline as it is called from hot
paths and also convert it into a static branch.
* tag 'trace-v5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Move user_events.h temporarily out of include/uapi
ftrace: Make ftrace_graph_is_dead() a static branch
tracing: Set user_events to BROKEN
tracing/user_events: Remove eBPF interfaces
tracing/user_events: Hold event_mutex during dyn_event_add
proc: bootconfig: Add null pointer check
tracing: Rename the staging files for trace_events
Pull powerpc fixes from Michael Ellerman:
- Fix KVM "lost kick" race, where an attempt to pull a vcpu out of the
guest could be lost (or delayed until the next guest exit).
- Disable SCV (system call vectored) when PR KVM guests could be run.
- Fix KVM PR guests using SCV, by disallowing AIL != 0 for KVM PR
guests.
- Add a new KVM CAP to indicate if AIL == 3 is supported.
- Fix a regression when hotplugging a CPU to a memoryless/cpuless node.
- Make virt_addr_valid() stricter for 64-bit Book3E & 32-bit, which
fixes crashes seen due to hardened usercopy.
- Revert a change to max_mapnr which broke HIGHMEM.
Thanks to Christophe Leroy, Fabiano Rosas, Kefeng Wang, Nicholas Piggin,
and Srikar Dronamraju.
* tag 'powerpc-5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
Revert "powerpc: Set max_mapnr correctly"
powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit
KVM: PPC: Move kvmhv_on_pseries() into kvm_ppc.h
powerpc/numa: Handle partially initialized numa nodes
powerpc/64: Fix build failure with allyesconfig in book3s_64_entry.S
KVM: PPC: Use KVM_CAP_PPC_AIL_MODE_3
KVM: PPC: Book3S PR: Disallow AIL != 0
KVM: PPC: Book3S PR: Disable SCV when AIL could be disabled
KVM: PPC: Book3S HV P9: Fix "lost kick" race
README