Pull RISC-V updates from Paul Walmsley:
- Enable parallel hotplug for RISC-V
- Optimize vector regset allocation for ptrace()
- Add a kernel selftest for the vector ptrace interface
- Enable the userspace RAID6 test to build and run using RISC-V vectors
- Add initial support for the Zalasr RISC-V ratified ISA extension
- For the Zicbop RISC-V ratified ISA extension to userspace, expose
hardware and kernel support to userspace and add a kselftest for
Zicbop
- Convert open-coded instances of 'asm goto's that are controlled by
runtime ALTERNATIVEs to use riscv_has_extension_{un,}likely(),
following arm64's alternative_has_cap_{un,}likely()
- Remove an unnecessary mask in the GFP flags used in some calls to
pagetable_alloc()
* tag 'riscv-for-linus-6.19-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
selftests/riscv: Add Zicbop prefetch test
riscv: hwprobe: Expose Zicbop extension and its block size
riscv: Introduce Zalasr instructions
riscv: hwprobe: Export Zalasr extension
dt-bindings: riscv: Add Zalasr ISA extension description
riscv: Add ISA extension parsing for Zalasr
selftests: riscv: Add test for the Vector ptrace interface
riscv: ptrace: Optimize the allocation of vector regset
raid6: test: Add support for RISC-V
raid6: riscv: Allow code to be compiled in userspace
raid6: riscv: Prevent compiler from breaking inline vector assembly code
riscv: cmpxchg: Use riscv_has_extension_likely
riscv: bitops: Use riscv_has_extension_likely
riscv: hweight: Use riscv_has_extension_likely
riscv: checksum: Use riscv_has_extension_likely
riscv: pgtable: Use riscv_has_extension_unlikely
riscv: Remove __GFP_HIGHMEM masking
RISC-V: Enable HOTPLUG_PARALLEL for secondary CPUs
Pull SoC dt updates from Arnd Bergmann:
"There are five sets of new SoCs that get added in existing families,
all of them being either upgrades or cut-down versions of the older
chips:
- Apple M2 Pro, M2 Max and M2 Ultra, used in the 2022/2023 generation
of high-end workstations and laptops from Apple. Linux has been
working on these for a while but stil requires patches.
- Axis Artpec8 is an Armv8 chip based on Samsung Exynos design,
unlike the earlier Armv7 Artpec6 from the same company that was
part of a separate family of chips.
- NXP i.MX91 is a cut-down version of i.MX93, using only a single
Cortex-A55 core.
- Qualcomm Lemans Auto is a variant of the Lemans SoC that was
originally merged under the sa8775p name, the differences being
mostly the firmware configuration of the platform.
- Four new Renesas SoCs RZ/T2H (r9a09g077m44), RZ/N2H (r9a09g087m44),
RZ/T2H (r9a09g077), and RZ/N2H (r9a09g087) are all industrial
bedded SoCs based on Cortex-A55 cores
In total, there are 65 new machines, including:
- Industrial embedded system and single-board computers based on NXP,
Allwinner, TI, Rockchips, Marvell, Xilinx Spacemit, Starfive chips.
- Reference boards for the newly added Renesas, Qualcomm, NXP and
Axis ARMv8 chips as well as Microchip's MPFS RISC-V SoC
- Laptops and Workstations using Apple M2 and Qualcomm Snapdragon X1
chips.
- Several Samsung phones using Qualcomm Snapdragon chips
- Set-top boxes based on Allwinner H313
- Five BMC boards using 32-bit ASpeed SoCs
- Three network routers using IXP4xx (ARMv5!) and Broadcom bcm4708
(ARMv7) SoCs
Two machines get phased out because they were available only in small
quantities but never made it into products: one STi407 based reference
board, and a Snapdragon 845 based Chromebook.
Aside from the newly added machines, a lot of work went into improving
hardware support on the existing machines and cleaning up contents for
validation"
* tag 'soc-dt-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (931 commits)
arm64: dts: apm-shadowcat: Drop "apm,xgene2-pcie" compatible
arm64: dts: apm-shadowcat: Move slimpro nodes out of "simple-bus" node
ARM: dts: microchip: sam9x7: Add qspi controller
arm64: dts: qcom: Add MST pixel streams for displayport
arm64: dts: qcom: sm6350: correct DP compatibility strings
arm64: dts: qcom: monaco-evk: Enable Adreno 623 GPU
arm64: dts: qcom: qcs8300-ride: Enable Adreno 623 GPU
arm64: dts: qcom: qcs8300: Add gpu and gmu nodes
arm64: dts: allwinner: h313: Add Amediatech X96Q
dt-bindings: arm: sunxi: Add Amediatech X96Q
arm64: dts: apple: t8015: Add SPMI node
arm64: dts: apple: t8012: Add SPMI node
arm64: dts: apple: Add J180d (Mac Pro, M2 Ultra, 2023) device tree
arm64: dts: rockchip: Add devicetree for the ROC-RK3588-RT
dt-bindings: arm: rockchip: Add Firefly ROC-RK3588-RT
arm64: dts: rockchip: update pinctrl names for Radxa E52C
arm64: dts: rockchip: remove vcc_3v3_pmu regulator for Radxa E52C
arm64: dts: apple: Add J474s, J475c and J475d device trees
arm64: dts: apple: Add J414 and J416 Macbook Pro device trees
arm64: dts: apple: Add initial t6020/t6021/t6022 DTs
...
Conor Dooley <conor@kernel.org> says:
From: Conor Dooley <conor.dooley@microchip.com>
Yo,
This series is partly leveraging Clement's work adding a validate
callback in the extension detection code so that things like checking
for whether a vector crypto extension is usable can be done like:
has_extension(<vector crypto>)
rather than
has_vector() && has_extension(<vector crypto>)
which Eric pointed out was a poor design some months ago.
The rest of this is adding some requirements to the bindings that
prevent combinations of extensions disallowed by the ISA.
There's a bunch of over-long lines in here, but I thought that the
over-long lines were clearer than breaking them up.
Cheers,
Conor.
* patches from https://lore.kernel.org/r/20250312-abide-pancreas-3576b8c44d2c@spud:
dt-bindings: riscv: document vector crypto requirements
dt-bindings: riscv: add vector sub-extension dependencies
dt-bindings: riscv: d requires f
RISC-V: add f & d extension validation checks
RISC-V: add vector crypto extension validation checks
RISC-V: add vector extension validation checks
Link: https://lore.kernel.org/r/20250312-abide-pancreas-3576b8c44d2c@spud
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Charlie Jenkins <charlie@rivosinc.com> says:
xtheadvector is a custom extension that is based upon riscv vector
version 0.7.1 [1]. All of the vector routines have been modified to
support this alternative vector version based upon whether xtheadvector
was determined to be supported at boot.
vlenb is not supported on the existing xtheadvector hardware, so a
devicetree property thead,vlenb is added to provide the vlenb to Linux.
There is a new hwprobe key RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 that is
used to request which thead vendor extensions are supported on the
current platform. This allows future vendors to allocate hwprobe keys
for their vendor.
Support for xtheadvector is also added to the vector kselftests.
[1] 95358cb2cc/xtheadvector.adoc
* b4-shazam-merge:
riscv: Add ghostwrite vulnerability
selftests: riscv: Support xtheadvector in vector tests
selftests: riscv: Fix vector tests
riscv: hwprobe: Document thead vendor extensions and xtheadvector extension
riscv: hwprobe: Add thead vendor extension probing
riscv: vector: Support xtheadvector save/restore
riscv: Add xtheadvector instruction definitions
riscv: csr: Add CSR encodings for CSR_VXRM/CSR_VXSAT
RISC-V: define the elements of the VCSR vector CSR
riscv: vector: Use vlenb from DT for thead
riscv: Add thead and xtheadvector as a vendor extension
riscv: dts: allwinner: Add xtheadvector to the D1/D1s devicetree
dt-bindings: cpus: add a thead vlen register length property
dt-bindings: riscv: Add xtheadvector ISA extension description
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-0-236c22791ef9@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Alexandre Ghiti <alexghiti@rivosinc.com> says:
This implements [cmp]xchgXX() macros using Zacas and Zabha extensions
and finally uses those newly introduced macros to add support for
qspinlocks: note that this implementation of qspinlocks satisfies the
forward progress guarantee.
It also uses Ziccrse to provide the qspinlock implementation.
Thanks to Guo and Leonardo for their work!
* b4-shazam-merge: (1314 commits)
riscv: Add qspinlock support
dt-bindings: riscv: Add Ziccrse ISA extension description
riscv: Add ISA extension parsing for Ziccrse
asm-generic: ticket-lock: Add separate ticket-lock.h
asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock
riscv: Implement xchg8/16() using Zabha
riscv: Implement arch_cmpxchg128() using Zacas
riscv: Improve zacas fully-ordered cmpxchg()
riscv: Implement cmpxchg8/16() using Zabha
dt-bindings: riscv: Add Zabha ISA extension description
riscv: Implement cmpxchg32/64() using Zacas
riscv: Do not fail to build on byte/halfword operations with Zawrs
riscv: Move cpufeature.h macros into their own header
Link: https://lore.kernel.org/r/20241103145153.105097-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Alexandre Ghiti <alexghiti@rivosinc.com> says:
In RISC-V, after a new mapping is established, a sfence.vma needs to be
emitted for different reasons:
- if the uarch caches invalid entries, we need to invalidate it otherwise
we would trap on this invalid entry,
- if the uarch does not cache invalid entries, a reordered access could fail
to see the new mapping and then trap (sfence.vma acts as a fence).
We can actually avoid emitting those (mostly) useless and costly sfence.vma
by handling the traps instead:
- for new kernel mappings: only vmalloc mappings need to be taken care of,
other new mapping are rare and already emit the required sfence.vma if
needed.
That must be achieved very early in the exception path as explained in
patch 3, and this also fixes our fragile way of dealing with vmalloc faults.
- for new user mappings: Svvptc makes update_mmu_cache() a no-op but we can
take some gratuitous page faults (which are very unlikely though).
Patch 1 and 2 introduce Svvptc extension probing.
On our uarch that does not cache invalid entries and a 6.5 kernel, the
gains are measurable:
* Kernel boot: 6%
* ltp - mmapstress01: 8%
* lmbench - lat_pagefault: 20%
* lmbench - lat_mmap: 5%
Here are the corresponding numbers of sfence.vma emitted:
* Ubuntu boot to login:
Before: ~630k sfence.vma
After: ~200k sfence.vma
* ltp - mmapstress01
Before: ~45k
After: ~6.3k
* lmbench - lat_pagefault
Before: ~665k
After: 832 (!)
* lmbench - lat_mmap
Before: ~546k
After: 718 (!)
Thanks to Ved and Matt Evans for triggering the discussion that led to
this patchset!
* b4-shazam-merge:
riscv: Stop emitting preventive sfence.vma for new userspace mappings with Svvptc
riscv: Stop emitting preventive sfence.vma for new vmalloc mappings
dt-bindings: riscv: Add Svvptc ISA extension description
riscv: Add ISA extension parsing for Svvptc
Link: https://lore.kernel.org/r/20240717060125.139416-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Andrew Jones <ajones@ventanamicro.com> says:
Zawrs provides two instructions (wrs.nto and wrs.sto), where both are
meant to allow the hart to enter a low-power state while waiting on a
store to a memory location. The instructions also both wait an
implementation-defined "short" duration (unless the implementation
terminates the stall for another reason). The difference is that while
wrs.sto will terminate when the duration elapses, wrs.nto, depending on
configuration, will either just keep waiting or an ILL exception will be
raised. Linux will use wrs.nto, so if platforms have an implementation
which falls in the "just keep waiting" category (which is not expected),
then it should _not_ advertise Zawrs in the hardware description.
Like wfi (and with the same {m,h}status bits to configure it), when
wrs.nto is configured to raise exceptions it's expected that the higher
privilege level will see the instruction was a wait instruction, do
something, and then resume execution following the instruction. For
example, KVM does configure exceptions for wfi (hstatus.VTW=1) and
therefore also for wrs.nto. KVM does this for wfi since it's better to
allow other tasks to be scheduled while a VCPU waits for an interrupt.
For waits such as those where wrs.nto/sto would be used, which are
typically locks, it is also a good idea for KVM to be involved, as it
can attempt to schedule the lock holding VCPU.
This series starts with Christoph's addition of the riscv
smp_cond_load_relaxed function which applies wrs.sto when available.
That patch has been reworked to use wrs.nto and to use the same approach
as Arm for the wait loop, since we can't have arbitrary C code between
the load-reserved and the wrs. Then, hwprobe support is added (since the
instructions are also usable from usermode), and finally KVM is
taught about wrs.nto, allowing guests to see and use the Zawrs
extension.
We still don't have test results from hardware, and it's not possible to
prove that using Zawrs is a win when testing on QEMU, not even when
oversubscribing VCPUs to guests. However, it is possible to use KVM
selftests to force a scenario where we can prove Zawrs does its job and
does it well. [4] is a test which does this and, on my machine, without
Zawrs it takes 16 seconds to complete and with Zawrs it takes 0.25
seconds.
This series is also available here [1]. In order to use QEMU for testing
a build with [2] is needed. In order to enable guests to use Zawrs with
KVM using kvmtool, the branch at [3] may be used.
[1] https://github.com/jones-drew/linux/commits/riscv/zawrs-v3/
[2] https://lore.kernel.org/all/20240312152901.512001-2-ajones@ventanamicro.com/
[3] https://github.com/jones-drew/kvmtool/commits/riscv/zawrs/
[4] cb2beccebc
Link: https://lore.kernel.org/r/20240426100820.14762-8-ajones@ventanamicro.com
* b4-shazam-merge:
KVM: riscv: selftests: Add Zawrs extension to get-reg-list test
KVM: riscv: Support guest wrs.nto
riscv: hwprobe: export Zawrs ISA extension
riscv: Add Zawrs support for spinlocks
dt-bindings: riscv: Add Zawrs ISA extension description
riscv: Provide a definition for 'pause'
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
intro
=====
When the RISC-V dt-bindings were accepted upstream in Linux, the base
ISA etc had yet to be ratified. By the ratification of the base ISA,
incompatible changes had snuck into the specifications - for example the
Zicsr and Zifencei extensions were spun out of the base ISA.
Fast forward to today, and the reason for this patch.
Currently the riscv,isa dt property permits only a specific subset of
the ISA string - in particular it excludes version numbering.
With the current constraints, it is not possible to discern whether
"rv64i" means that the hart supports the fence.i instruction, for
example.
Future systems may choose to implement their own instruction fencing,
perhaps using a vendor extension, or they may not implement the optional
counter extensions. Software needs a way to determine this.
versioning schemes
==================
"Use the extension versions that are described in the ISA manual" you
may say, and it's not like this has not been considered.
Firstly, software that parses the riscv,isa property at runtime will
need to contain a lookup table of some sort that maps arbitrary versions
to versions it understands. There is not a consistent application of
version number applied to extensions, with a higgledy-piggledy
collection of tags, "bare" and versioned documents awaiting the reader
on the "recently ratified extensions" page:
https://wiki.riscv.org/display/HOME/Recently+Ratified+Extensions
As an aside, and this is reflected in the patch too, since many
extensions have yet to appear in a release of the ISA specs,
they are defined by commits in their respective "working draft"
repositories.
Secondly, there is an issue of backwards compatibility, whereby allowing
numbers in the ISA string, some parsers may be broken. This would
require an additional property to be created to even use the versions in
this manner.
~boolean properties~ string array property
==========================================
If a new property is needed, the whole approach may as well be looked at
from the bottom up. A string with limited character choices etc is
hardly the best approach for communicating extension information to
software.
Switching to using properties that are defined on a per extension basis,
allows us to define explicit meanings for the DT representation of each
extension - rather than the current situation where different operating
systems or other bits of software may impart different meanings to
characters in the string.
Clearly the best source of meanings is the specifications themselves,
this just provides us the ability to choose at what point in time the
meaning is set. If an extension changes incompatibility in the future,
a new property will be required.
Off-list, some of the RVI folks have committed to shoring up the wording
in either the ISA specifications, the riscv-isa-manual or
so that in the future, modifications to and additions or removals of
features will require a new extension. Codifying that assertion
somewhere would make it quite unlikely that compatibility would be
broken, but we have the tools required to deal with it, if & when it
crops up.
It is in our collective interest, as consumers of extension meanings, to
define a scheme that enforces compatibility.
The use of individual elements, rather than a single string, will also
permit validation that the properties have a meaning, as well as
potentially reject mutually exclusive combinations, or enforce
dependencies between extensions. That would not have be possible with
the current dt-schema infrastructure for arbitrary strings, as we would
need to add a riscv,isa parser to dt-validate!
That's not implemented in this patch, but rather left as future work (for
the brave, or the foolish).
parser simplicity
=================
Many systems that parse DT at runtime already implement an function that
can check for the presence of a string in an array of string, as it is
similar to the process for parsing a list of compatible strings, so a
bunch of new, custom, DT parsing should not be needed.
Getting rid of "riscv,isa" parsing would be a nice simplification, but
unfortunately for backwards compatibility with old dtbs, existing
parsers may not be removable - which may greatly simplify
dt parsing code. In Linux, for example, checking for whether a hart
supports an extension becomes as simple as:
of_property_match_string(node, "riscv,isa-extensions", "zicbom")
vendor extensions
=================
Compared to riscv,isa, this proposed scheme promotes vendor extensions,
oft touted as the strength of RISC-V, to first-class citizens.
At present, extensions are defined as meaning what the RISC-V ISA
specifications say they do. There is no realistic way of using that
interface to provide cross-platform definitions for what vendor
extensions mean. Vendor extensions may also have even less consistency
than RVI do in terms of versioning, or no care about backwards
compatibility.
The new property allows us to assign explicit meanings on a per vendor
extension basis, backed up by a description of their meanings.
fin
===
Create a new file to store the extension meanings and a new
riscv,isa-base property to replace the aspect of riscv,isa that is
not represented by the new property - the base ISA implemented by a hart.
As a starting point, add properties for extensions currently used in
Linux.
Finally, mark riscv,isa as deprecated, as removing support for it in
existing programs would be an ABI break.
CC: Palmer Dabbelt <palmer@dabbelt.com>
CC: Paul Walmsley <paul.walmsley@sifive.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
CC: Alistair Francis <alistair.francis@wdc.com>
CC: Andrew Jones <ajones@ventanamicro.com>
CC: Anup Patel <apatel@ventanamicro.com>
CC: Atish Patra <atishp@atishpatra.org>
CC: Jessica Clarke <jrtc27@jrtc27.com>
CC: Rick Chen <rick@andestech.com>
CC: Leo <ycliang@andestech.com>
CC: Oleksii <oleksii.kurochko@gmail.com>
CC: linux-riscv@lists.infradead.org
CC: qemu-riscv@nongnu.org
CC: u-boot@lists.denx.de
CC: devicetree@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230702-eats-scorebook-c951f170d29f@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
