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
code
Clone this repository
https://tangled.org/tjh.dev/kernel
git@gordian.tjh.dev:tjh.dev/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Pull Kbuild fixes from Masahiro Yamada:
- Remove unused scripts/gcc-ld script
- Add zstd support to scripts/extract-ikconfig
- Check 'make headers' for UML
- Fix scripts/mksysmap to ignore local symbols
* tag 'kbuild-fixes-v6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
mksysmap: Fix the mismatch of 'L0' symbols in System.map
kbuild: disable header exports for UML in a straightforward way
scripts/extract-ikconfig: add zstd compression support
scripts: remove obsolete gcc-ld script
Pull arm64 fixes from Will Deacon:
"Three small arm64 fixes, all related to optional architecture
extensions: BTI, SME and 52-bit virtual addressing:
- Disable in-kernel BTI when compiling with GCC, as it makes invalid
assumptions about the distance between functions which has led to
crashes when calling modules on a CPU with BTI support
- Remove bogus TIF_SME flag management if memory allocation fails in
the ptrace code
- Fix the resume path when configured for 52-bit virtual addressing"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: mm: fix resume for 52-bit enabled builds
arm64/ptrace: Don't clear calling process' TIF_SME on OOM
arm64/bti: Disable in kernel BTI when cross section thunks are broken
When System.map was generated, the kernel used mksysmap to filter the
kernel symbols, we need to filter "L0" symbols in LoongArch architecture.
$ cat System.map | grep L0
9000000000221540 t L0
The L0 symbol exists in System.map, but not in .tmp_System.map. When
"cmp -s System.map .tmp_System.map" will show "Inconsistent kallsyms
data" error message in link-vmlinux.sh script.
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull i2c fixes from Wolfram Sang:
"Only documentation and DT binding fixes and improvements"
* tag 'i2c-for-6.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
dt-bindings: i2c: renesas,riic: Fix 'unevaluatedProperties' warnings
docs: i2c: piix4: Fix typos, add markup, drop link
docs: i2c: i2c-topology: reorder sections more logically
docs: i2c: i2c-topology: fix incorrect heading
docs: i2c: i2c-topology: fix typo
__cpu_setup() was changed to take the actual number of VA bits in x0,
however the resume path was not updated at the same time.
Load `vabits_actual` in the resume path, to ensure that the correct
number of VA bits is used.
This fixes booting v6.0-rc kernels on my Juno.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Fixes: 0aaa68532e9d ("arm64: mm: fix booting with 52-bit address space")
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220909124311.38489-1-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Previously 'make ARCH=um headers' stopped because of missing
arch/um/include/uapi/asm/Kbuild.
The error is not shown since commit ed102bf2afed ("um: Fix W=1
missing-include-dirs warnings") added arch/um/include/uapi/asm/Kbuild.
Hard-code the unsupported architecture, so it works like before.
Fixes: ed102bf2afed ("um: Fix W=1 missing-include-dirs warnings")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Richard Weinberger <richard@nod.at>
Pull iommu fixes from Joerg Roedel:
- Intel VT-d fixes from Lu Baolu:
- Boot kdump kernels with VT-d scalable mode on
- Calculate the right page table levels
- Fix two recursive locking issues
- Fix a lockdep splat issue
- AMD IOMMU fixes:
- Fix for completion-wait command to use full 64 bits of data
- Fix PASID related issue where GPU sound devices failed to
initialize
- Fix for Virtio-IOMMU to report correct caching behavior, needed for
use with VFIO
* tag 'iommu-fixes-v6.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu: Fix false ownership failure on AMD systems with PASID activated
iommu/vt-d: Fix possible recursive locking in intel_iommu_init()
iommu/virtio: Fix interaction with VFIO
iommu/vt-d: Fix lockdep splat due to klist iteration in atomic context
iommu/vt-d: Fix recursive lock issue in iommu_flush_dev_iotlb()
iommu/vt-d: Correctly calculate sagaw value of IOMMU
iommu/vt-d: Fix kdump kernels boot failure with scalable mode
iommu/amd: use full 64-bit value in build_completion_wait()
With 'unevaluatedProperties' support implemented, there's a number of
warnings when running dtbs_check:
arch/arm64/boot/dts/renesas/r9a07g043u11-smarc.dtb: i2c@10058000: Unevaluated properties are not allowed ('resets' was unexpected)
From schema: Documentation/devicetree/bindings/i2c/renesas,riic.yaml
The main problem is that bindings schema marks resets as a required
property for RZ/G2L (and alike) SoC's but resets property is not part
of schema. So to fix this just add a resets property with maxItems
set to 1.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
If allocating memory for the target SVE state in za_set() fails we clear
TIF_SME for the ptracing task which is obviously not correct. If we are
here we know that the target task already had neither TIF_SVE nor
TIF_SME set since we only need to allocate if either the target had not
used either SVE or SME and had no need to allocate state before or we
just changed the vector length with vec_set_vector_length() which clears
TIF_ for us on allocation failure so just remove the clear entirely.
Reported-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220902132802.39682-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Add extract-ikconfig support for kernel images compressed with zstd.
Signed-off-by: Thitat Auareesuksakul <thitat@flux.ci>
Tested-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull MIPS fixes from Thomas Bogendoerfer:
- fix for loongson32 starup hang
- fix for octeon irq setup problem
- fix compiler warning for new CONFIG option
- switch to SPARSEMEM_EXTREME for all platforms selecting SPARSEMEM
* tag 'mips-fixes_6.0_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
mips: Select SPARSEMEM_EXTREME
MIPS: OCTEON: irq: Fix octeon_irq_force_ciu_mapping()
MIPS: octeon: Get rid of preprocessor directives around RESERVE32
MIPS: loongson32: ls1c: Fix hang during startup
The AMD IOMMU driver cannot activate PASID mode on a RID without the RID's
translation being set to IDENTITY. Further it requires changing the RID's
page table layout from the normal v1 IOMMU_DOMAIN_IDENTITY layout to a
different v2 layout.
It does this by creating a new iommu_domain, configuring that domain for
v2 identity operation and then attaching it to the group, from within the
driver. This logic assumes the group is already set to the IDENTITY domain
and is being used by the DMA API.
However, since the ownership logic is based on the group's domain pointer
equaling the default domain to detect DMA API ownership, this causes it to
look like the group is not attached to the DMA API any more. This blocks
attaching drivers to any other devices in the group.
In a real system this manifests itself as the HD-audio devices on some AMD
platforms losing their device drivers.
Work around this unique behavior of the AMD driver by checking for
equality of IDENTITY domains based on their type, not their pointer
value. This allows the AMD driver to have two IDENTITY domains for
internal purposes without breaking the check.
Have the AMD driver properly declare that the special domain it created is
actually an IDENTITY domain.
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: stable@vger.kernel.org
Fixes: 512881eacfa7 ("bus: platform,amba,fsl-mc,PCI: Add device DMA ownership management")
Reported-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/0-v1-ea566e16b06b+811-amd_owner_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
[JD: Update the subject
One more typo fixed
Drop the link to lm-sensors' README, it's irrelevant]
Signed-off-by: Bruce Duncan <bwduncan@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
GCC does not insert a `bti c` instruction at the beginning of a function
when it believes that all callers reach the function through a direct
branch[1]. Unfortunately the logic it uses to determine this is not
sufficiently robust, for example not taking account of functions being
placed in different sections which may be loaded separately, so we may
still see thunks being generated to these functions. If that happens,
the first instruction in the callee function will result in a Branch
Target Exception due to the missing landing pad.
While this has currently only been observed in the case of modules
having their main code loaded sufficiently far from their init section
to require thunks it could potentially happen for other cases so the
safest thing is to disable BTI for the kernel when building with an
affected toolchain.
[1]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106671
Reported-by: D Scott Phillips <scott@os.amperecomputing.com>
[Bits of the commit message are lifted from his report & workaround]
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220905142255.591990-1-broonie@kernel.org
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Will Deacon <will@kernel.org>
README