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Zicbop introduces cache blocks prefetching instructions, add the
necessary support for the kernel to use it in the coming commits.
Co-developed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Tested-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20250421142441.395849-3-alexghiti@rivosinc.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
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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>
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Using Clement's new validation callbacks, support checking that
dependencies have been satisfied for the floating point extensions.
The check for "d" might be slightly confusingly shorter than that of "f",
despite "d" depending on "f". This is because the requirement that a
hart supporting double precision must also support single precision,
should be validated by dt-bindings etc, not the kernel but lack of
support for single precision only is a limitation of the kernel.
Tested-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250312-reptile-platinum-62ee0f444a32@spud
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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Using Clement's new validation callbacks, support checking that
dependencies have been satisfied for the vector crpyto extensions.
Currently riscv_isa_extension_available(<vector crypto>) will return
true on systems that support the extensions but vector itself has been
disabled by the kernel, adding validation callbacks will prevent such a
scenario from occuring and make the behaviour of the extension detection
functions more consistent with user expectations - it's not expected to
have to check for vector AND the specific crypto extension.
The Unpriv spec states:
| The Zvknhb and Zvbc Vector Crypto Extensions --and accordingly the
| composite extensions Zvkn, Zvknc, Zvkng, and Zvksc-- require a Zve64x
| base, or application ("V") base Vector Extension. All of the other
| Vector Crypto Extensions can be built on any embedded (Zve*) or
| application ("V") base Vector Extension.
While this could be used as the basis for checking that the correct base
for individual crypto extensions, but that's not really the kernel's job
in my opinion and it is sufficient to leave that sort of precision to
the dt-bindings. The kernel only needs to make sure that vector, in some
form, is available.
Link: https://github.com/riscv/riscv-isa-manual/blob/main/src/vector-crypto.adoc#extensions-overview
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250312-entertain-shaking-b664142c2f99@spud
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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Using Clement's new validation callbacks, support checking that
dependencies have been satisfied for the vector extensions. From the
kernel's perfective, it's not required to differentiate between the
conditions for all the various vector subsets - it's the firmware's job
to not report impossible combinations. Instead, the kernel only has to
check that the correct config options are enabled and to enforce its
requirement of the d extension being present for FPU support.
Since vector will now be disabled proactively, there's no need to clear
the bit in elf_hwcap in riscv_fill_hwcap() any longer.
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250312-eclair-affluent-55b098c3602b@spud
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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These 2 new extensions are actually a subset of the A extension which
provides atomic memory operations and load-reserved/store-conditional
instructions.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240619153913.867263-3-cleger@rivosinc.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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Reduce three lines checking to single line using a ternary conditional
expression for getting the base extension word. In addition, the
test_bit macro function already return a boolean which matches the
return type of the caller, so directly return the result of the test_bit
macro function.
Signed-off-by: Chin Yik Ming <yikming2222@gmail.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20250129203843.1136838-1-yikming2222@gmail.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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Enabling cbo.clean and cbo.flush in user mode makes it more
convenient to manage the cache state and achieve better performance.
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Link: https://lore.kernel.org/r/20250226063206.71216-2-cuiyunhui@bytedance.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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Inochi Amaoto <inochiama@gmail.com> says:
Add description for the BFloat16 precision Floating-Point ISA extension,
(Zfbfmin, Zvfbfmin, Zvfbfwma). which was ratified in commit 4dc23d62
("Added Chapter title to BF16") of the riscv-isa-manual.
* patches from https://lore.kernel.org/r/20250213003849.147358-1-inochiama@gmail.com:
riscv: hwprobe: export bfloat16 ISA extension
riscv: add ISA extension parsing for bfloat16 ISA extension
dt-bindings: riscv: add bfloat16 ISA extension description
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250213003849.147358-1-inochiama@gmail.com
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Add parsing for Zfbmin, Zvfbfmin, Zvfbfwma ISA extension which
were ratified in 4dc23d62 ("Added Chapter title to BF16") of
the riscv-isa-manual.
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20250213003849.147358-3-inochiama@gmail.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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Comparison of bitmaps should be done using bitmap_equal(), not memcmp(),
use the former one to compare isa bitmaps.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Fixes: 625034abd52a8c ("riscv: add ISA extensions validation callback")
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250210155615.1545738-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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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] https://github.com/T-head-Semi/thead-extension-spec/blob/95358cb2cca9489361c61d335e03d3134b14133f/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>
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Follow the patterns of the other architectures that use
GENERIC_CPU_VULNERABILITIES for riscv to introduce the ghostwrite
vulnerability and mitigation. The mitigation is to disable all vector
which is accomplished by clearing the bit from the cpufeature field.
Ghostwrite only affects thead c9xx CPUs that impelment xtheadvector, so
the vulerability will only be mitigated on these CPUs.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Yangyu Chen <cyy@cyyself.name>
Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-14-236c22791ef9@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Use alternatives to add support for xtheadvector vector save/restore
routines.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Yangyu Chen <cyy@cyyself.name>
Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-9-236c22791ef9@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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If thead,vlenb is provided in the device tree, prefer that over reading
the vlenb csr.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Yangyu Chen <cyy@cyyself.name>
Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-5-236c22791ef9@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Add support to the kernel for THead vendor extensions with the target of
the new extension xtheadvector.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Yangyu Chen <cyy@cyyself.name>
Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-4-236c22791ef9@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Pull more kvm updates from Paolo Bonzini:
- ARM fixes
- RISC-V Svade and Svadu (accessed and dirty bit) extension support for
host and guest
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: riscv: selftests: Add Svade and Svadu Extension to get-reg-list test
RISC-V: KVM: Add Svade and Svadu Extensions Support for Guest/VM
dt-bindings: riscv: Add Svade and Svadu Entries
RISC-V: Add Svade and Svadu Extensions Support
KVM: arm64: Use MDCR_EL2.HPME to evaluate overflow of hyp counters
KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status
KVM: arm64: Mark set_sysreg_masks() as inline to avoid build failure
KVM: arm64: vgic-its: Add stronger type-checking to the ITS entry sizes
KVM: arm64: vgic: Kill VGIC_MAX_PRIVATE definition
KVM: arm64: vgic: Make vgic_get_irq() more robust
KVM: arm64: vgic-v3: Sanitise guest writes to GICR_INVLPIR
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-v updates from Palmer Dabbelt:
- Support for pointer masking in userspace
- Support for probing vector misaligned access performance
- Support for qspinlock on systems with Zacas and Zabha
* tag 'riscv-for-linus-6.13-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (38 commits)
RISC-V: Remove unnecessary include from compat.h
riscv: Fix default misaligned access trap
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
KVM: riscv: selftests: Add Smnpm and Ssnpm to get-reg-list test
RISC-V: KVM: Allow Smnpm and Ssnpm extensions for guests
riscv: hwprobe: Export the Supm ISA extension
riscv: selftests: Add a pointer masking test
riscv: Allow ptrace control of the tagged address ABI
...
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KVM/riscv changes for 6.13 part #2
- Svade and Svadu extension support for Host and Guest/VM
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Svade and Svadu extensions represent two schemes for managing the PTE A/D
bits. When the PTE A/D bits need to be set, Svade extension intdicates
that a related page fault will be raised. In contrast, the Svadu extension
supports hardware updating of PTE A/D bits. Since the Svade extension is
mandatory and the Svadu extension is optional in RVA23 profile, by default
the M-mode firmware will enable the Svadu extension in the menvcfg CSR
when only Svadu is present in DT.
This patch detects Svade and Svadu extensions from DT and adds
arch_has_hw_pte_young() to enable optimization in MGLRU and
__wp_page_copy_user() when we have the PTE A/D bits hardware updating
support.
Co-developed-by: Jinyu Tang <tjytimi@163.com>
Signed-off-by: Jinyu Tang <tjytimi@163.com>
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20240726084931.28924-2-yongxuan.wang@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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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>
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Add support to parse the Ziccrse string in the riscv,isa string.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-12-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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This adds runtime support for Zabha in cmpxchg8/16() operations.
Note that in the absence of Zacas support in the toolchain, CAS
instructions from Zabha won't be used.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20241103145153.105097-6-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Several architectures support text patching, but they name the header
files that declare patching functions differently.
Make all such headers consistently named text-patching.h and add an empty
header in asm-generic for architectures that do not support text patching.
Link: https://lkml.kernel.org/r/20241023162711.2579610-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: kdevops <kdevops@lists.linux.dev>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The RISC-V Pointer Masking specification defines three extensions:
Smmpm, Smnpm, and Ssnpm. Add support for parsing each of them. The
specific extension which provides pointer masking support to userspace
(Supm) depends on the kernel's privilege mode, so provide a macro to
abstract this selection.
Smmpm implies the existence of the mseccfg CSR. As it is the only user
of this CSR so far, there is no need for an Xlinuxmseccfg extension.
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20241016202814.4061541-3-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Now that the [ms]envcfg CSR value is maintained per thread, not per
hart, riscv_user_isa_enable() only needs to be called once during boot,
to set the value for the init task. This also allows it to be marked as
__init.
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Deepak Gupta <debug@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240814081126.956287-4-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Some bits in the [ms]envcfg CSR, such as the CFI state and pointer
masking mode, need to be controlled on a per-thread basis. Support this
by keeping a copy of the CSR value in struct thread_struct and writing
it during context switches. It is safe to discard the old CSR value
during the context switch because the CSR is modified only by software,
so the CSR will remain in sync with the copy in thread_struct.
Use ALTERNATIVE directly instead of riscv_has_extension_unlikely() to
minimize branchiness in the context switching code.
Since thread_struct is copied during fork(), setting the value for the
init task sets the default value for all other threads.
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Deepak Gupta <debug@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240814081126.956287-3-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Currently, we enable cbo.zero for usermode on each hart that supports
the Zicboz extension. This means that the [ms]envcfg CSR value may
differ between harts. Other features, such as pointer masking and CFI,
require setting [ms]envcfg bits on a per-thread basis. The combination
of these two adds quite some complexity and overhead to context
switching, as we would need to maintain two separate masks for the
per-hart and per-thread bits. Andrew Jones, who originally added Zicboz
support, writes[1][2]:
I've approached Zicboz the same way I would approach all
extensions, which is to be per-hart. I'm not currently aware of
a platform that is / will be composed of harts where some have
Zicboz and others don't, but there's nothing stopping a platform
like that from being built.
So, how about we add code that confirms Zicboz is on all harts.
If any hart does not have it, then we complain loudly and disable
it on all the other harts. If it was just a hardware description
bug, then it'll get fixed. If there's actually a platform which
doesn't have Zicboz on all harts, then, when the issue is reported,
we can decide to not support it, support it with defconfig, or
support it under a Kconfig guard which must be enabled by the user.
Let's follow his suggested solution and require the extension to be
available on all harts, so the envcfg CSR value does not need to change
when a thread migrates between harts. Since we are doing this for all
extensions with fields in envcfg, the CSR itself only needs to be saved/
restored when it is present on all harts.
This should not be a regression as no known hardware has asymmetric
Zicboz support, but if anyone reports seeing the warning, we will
re-evaluate our solution.
Link: https://lore.kernel.org/linux-riscv/20240322-168f191eeb8479b2ea169a5e@orel/ [1]
Link: https://lore.kernel.org/linux-riscv/20240323-28943722feb57a41fb0ff488@orel/ [2]
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Deepak Gupta <debug@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240814081126.956287-2-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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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>
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Add support to parse the Svvptc string in the riscv,isa string.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240717060125.139416-2-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The Linux-internal Xlinuxenvcfg ISA extension is omitted from the
riscv_isa_ext array because it has no DT binding and should not appear
in /proc/cpuinfo. The logic added in commit 625034abd52a ("riscv: add
ISA extensions validation callback") assumes all extensions are included
in riscv_isa_ext, and so riscv_resolve_isa() wrongly drops Xlinuxenvcfg
from the final ISA string. Instead, accept such Linux-internal ISA
extensions as if they have no validation callback.
Fixes: 625034abd52a ("riscv: add ISA extensions validation callback")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240718213011.2600150-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Instead of grouping all vendor extensions into the same riscv_isa_ext
that standard instructions use, create a struct
"riscv_isa_vendor_ext_data_list" that allows each vendor to maintain
their vendor extensions independently of the standard extensions.
xandespmu is currently the only vendor extension so that is the only
extension that is affected by this change.
An additional benefit of this is that the extensions of each vendor can
be conditionally enabled. A config RISCV_ISA_VENDOR_EXT_ANDES has been
added to allow for that.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andy Chiu <andy.chiu@sifive.com>
Tested-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Link: https://lore.kernel.org/r/20240719-support_vendor_extensions-v3-1-0af7587bbec0@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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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] https://github.com/jones-drew/linux/commit/cb2beccebcece10881db842ed69bdd5715cfab5d
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>
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RISC-V code uses the generic ticket lock implementation, which calls
the macros smp_cond_load_relaxed() and smp_cond_load_acquire().
Introduce a RISC-V specific implementation of smp_cond_load_relaxed()
which applies WRS.NTO of the Zawrs extension in order to reduce power
consumption while waiting and allows hypervisors to enable guests to
trap while waiting. smp_cond_load_acquire() doesn't need a RISC-V
specific implementation as the generic implementation is based on
smp_cond_load_relaxed() and smp_acquire__after_ctrl_dep() sufficiently
provides the acquire semantics.
This implementation is heavily based on Arm's approach which is the
approach Andrea Parri also suggested.
The Zawrs specification can be found here:
https://github.com/riscv/riscv-zawrs/blob/main/zawrs.adoc
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Co-developed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240426100820.14762-11-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Add parsing for Zcmop ISA extension which was ratified in commit
c732a4f39a4c ("Zcmop is ratified/1.0") of the riscv-isa-manual.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240619113529.676940-14-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The Zc* standard extension for code reduction introduces new extensions.
This patch adds support for Zca, Zcf, Zcd and Zcb. Zce, Zcmt and Zcmp
are left out of this patch since they are targeting microcontrollers/
embedded CPUs instead of application processors.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240619113529.676940-9-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Since a few extensions (Zicbom/Zicboz) already needs validation and
future ones will need it as well (Zc*) add a validate() callback to
struct riscv_isa_ext_data. This require to rework the way extensions are
parsed and split it in two phases. First phase is isa string or isa
extension list parsing and consists in enabling all the extensions in a
temporary bitmask (source isa) without any validation. The second step
"resolves" the final isa bitmap, handling potential missing dependencies.
The mechanism is quite simple and simply validate each extension
described in the source bitmap before enabling it in the resolved isa
bitmap. validate() callbacks can return either 0 for success,
-EPROBEDEFER if extension needs to be validated again at next loop. A
previous ISA bitmap is kept to avoid looping multiple times if an
extension dependencies are never satisfied until we reach a stable
state. In order to avoid any potential infinite looping, allow looping
a maximum of the number of extension we handle. Zicboz and Zicbom
extensions are modified to use this validation mechanism.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240619113529.676940-8-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Add parsing for Zimop ISA extension which was ratified in commit
58220614a5f of the riscv-isa-manual.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240619113529.676940-3-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Make has_vector() to check for ZVE32X. Every in-kernel usage of V that
requires a more complicate version of V must then call out explicitly.
Also, change riscv_v_first_use_handler(), and boot code that calls
riscv_v_setup_vsize() to accept ZVE32X.
Most kernel/user interfaces requires minimum of ZVE32X. Thus, programs
compiled and run with ZVE32X should be supported by the kernel on most
aspects. This includes context-switch, signal, ptrace, prctl, and
hwprobe.
One exception is that ELF_HWCAP returns 'V' only if full V is supported
on the platform. This means that the system without a full V must not
rely on ELF_HWCAP to tell whether it is allowable to execute Vector
without first invoking a prctl() check.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Joel Granados <j.granados@samsung.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-7-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Multiple Vector subextensions are added. Also, the patch takes care of
the dependencies of Vector subextensions by macro expansions. So, if
some "embedded" platform only reports "zve64f" on the ISA string, the
parser is able to expand it to zve32x zve32f zve64x and zve64f.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-5-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Single-letter extensions may also imply multiple subextensions. For
example, Vector extension implies zve64d, and zve64d implies zve64f.
Extension parsing for "riscv,isa-extensions" has the ability to resolve
the dependency by calling match_isa_ext(). This patch makes deprecated
parser call the same function for single letter extensions.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-3-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The function would fail when it detects the calling hart's vlen doesn't
match the first one's. The boot hart is the first hart calling this
function during riscv_fill_hwcap, so it is impossible to fail here. Add
a comment about this behavior.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-1-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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This loop is supposed to check if ext->subset_ext_ids[j] is valid, rather
than if ext->subset_ext_ids[i] is valid, before setting the extension
id ext->subset_ext_ids[j] in isainfo->isa.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Fixes: 0d8295ed975b ("riscv: add ISA extension parsing for scalar crypto")
Link: https://lore.kernel.org/r/20240502-cpufeature_fixes-v4-2-b3d1a088722d@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The riscv_cpuinfo struct that contains mvendorid and marchid is not
populated until all harts are booted which happens after the DT parsing.
Use the mvendorid/marchid from the boot hart to determine if the DT
contains an invalid V.
Fixes: d82f32202e0d ("RISC-V: Ignore V from the riscv,isa DT property on older T-Head CPUs")
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20240502-cpufeature_fixes-v4-1-b3d1a088722d@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Palmer Dabbelt:
- Support for various vector-accelerated crypto routines
- Hibernation is now enabled for portable kernel builds
- mmap_rnd_bits_max is larger on systems with larger VAs
- Support for fast GUP
- Support for membarrier-based instruction cache synchronization
- Support for the Andes hart-level interrupt controller and PMU
- Some cleanups around unaligned access speed probing and Kconfig
settings
- Support for ACPI LPI and CPPC
- Various cleanus related to barriers
- A handful of fixes
* tag 'riscv-for-linus-6.9-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (66 commits)
riscv: Fix syscall wrapper for >word-size arguments
crypto: riscv - add vector crypto accelerated AES-CBC-CTS
crypto: riscv - parallelize AES-CBC decryption
riscv: Only flush the mm icache when setting an exec pte
riscv: Use kcalloc() instead of kzalloc()
riscv/barrier: Add missing space after ','
riscv/barrier: Consolidate fence definitions
riscv/barrier: Define RISCV_FULL_BARRIER
riscv/barrier: Define __{mb,rmb,wmb}
RISC-V: defconfig: Enable CONFIG_ACPI_CPPC_CPUFREQ
cpufreq: Move CPPC configs to common Kconfig and add RISC-V
ACPI: RISC-V: Add CPPC driver
ACPI: Enable ACPI_PROCESSOR for RISC-V
ACPI: RISC-V: Add LPI driver
cpuidle: RISC-V: Move few functions to arch/riscv
riscv: Introduce set_compat_task() in asm/compat.h
riscv: Introduce is_compat_thread() into compat.h
riscv: add compile-time test into is_compat_task()
riscv: Replace direct thread flag check with is_compat_task()
riscv: Improve arch_get_mmap_end() macro
...
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Charlie Jenkins <charlie@rivosinc.com> says:
If the hardware unaligned access speed is known at compile time, it is
possible to avoid running the unaligned access speed probe to speedup
boot-time.
* b4-shazam-merge:
riscv: Set unaligned access speed at compile time
riscv: Decouple emulated unaligned accesses from access speed
riscv: Only check online cpus for emulated accesses
riscv: lib: Introduce has_fast_unaligned_access()
Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-0-a388770ba0ce@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Introduce Kconfig options to set the kernel unaligned access support.
These options provide a non-portable alternative to the runtime
unaligned access probe.
To support this, the unaligned access probing code is moved into it's
own file and gated behind a new RISCV_PROBE_UNALIGNED_ACCESS_SUPPORT
option.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-4-a388770ba0ce@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Detecting if a system traps into the kernel on an unaligned access
can be performed separately from checking the speed of unaligned
accesses. This decoupling will make it possible to selectively enable
or disable each of these checks.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-3-a388770ba0ce@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Create has_fast_unaligned_access to avoid needing to explicitly check
the fast_misaligned_access_speed_key static key.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240308-disable_misaligned_probe_config-v9-1-a388770ba0ce@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Assign riscv_pmu_irq_num the value of (256 + 18) for the custome PMU
and add SSCOUNTOVF and SIP alternatives to ALT_SBI_PMU_OVERFLOW()
and ALT_SBI_PMU_OVF_CLEAR_PENDING() macros, respectively.
To make use of Andes PMU extension, "xandespmu" needs to be appended
to the riscv,isa-extensions for each cpu node in device-tree, and
make sure CONFIG_ANDES_CUSTOM_PMU is enabled.
Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Charles Ci-Jyun Wu <dminus@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Co-developed-by: Locus Wei-Han Chen <locus84@andestech.com>
Signed-off-by: Locus Wei-Han Chen <locus84@andestech.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20240222083946.3977135-8-peterlin@andestech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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