This cleans up the ISA string handling to more closely match a version
of the ISA spec. This is visible in /proc/cpuinfo and the ordering
changes may break something in userspace, but these orderings have
changed before without issues so with any luck that's still the case.
This also adds documentation so userspace has a better idea of what is
intended when it comes to compatibility for /proc/cpuinfo, which should
help everyone as this will likely keep changing.
* b4-shazam-merge:
Documentation: riscv: add a section about ISA string ordering in /proc/cpuinfo
RISC-V: resort all extensions in consistent orders
RISC-V: clarify ISA string ordering rules in cpu.c
Link: https://lore.kernel.org/r/20221205144525.2148448-1-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Ordering between each and every list of extensions is wildly
inconsistent. Per discussion on the lists pick the following policy:
- The array defining order in /proc/cpuinfo follows a narrow
interpretation of the ISA specifications, described in a comment
immediately presiding it.
- All other lists of extensions are sorted alphabetically.
This will hopefully allow for easier review & future additions, and
reduce conflicts between patchsets as the number of extensions grows.
Link: https://lore.kernel.org/all/20221129144742.2935581-2-conor.dooley@microchip.com/
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221205144525.2148448-3-conor.dooley@microchip.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Add a static assert to ensure a RISCV_ISA_EXT_* enum is never
created with a value >= RISCV_ISA_EXT_MAX. We can do this by
putting RISCV_ISA_EXT_ID_MAX to more work. Before it was
redundant with RISCV_ISA_EXT_MAX and hence only used to
document the limit. Now it grows with the enum and is used to
check the limit.
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221201113750.18021-1-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Just like other ISA extensions, we allow callers/users to detect the
presence of Svinval extension from ISA string.
Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
This series implements Sstc extension support which was ratified
recently. Before the Sstc extension, an SBI call is necessary to
generate timer interrupts as only M-mode have access to the timecompare
registers. Thus, there is significant latency to generate timer
interrupts at kernel. For virtualized enviornments, its even worse as
the KVM handles the SBI call and uses a software timer to emulate the
timecomapre register.
Sstc extension solves both these problems by defining a
stimecmp/vstimecmp at supervisor (host/guest) level. It allows kernel to
program a timer and recieve interrupt without supervisor execution
enviornment (M-mode/HS mode) intervention.
* palmer/riscv-sstc:
RISC-V: Prefer sstc extension if available
RISC-V: Enable sstc extension parsing from DT
RISC-V: Add SSTC extension CSR details
The ISA extension framework now allows parsing any multi-letter
ISA extension.
Enable that for sstc extension.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20220722165047.519994-3-atishp@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The Zicbom ISA-extension was ratified in november 2021
and introduces instructions for dcache invalidate, clean
and flush operations.
Implement cache management operations for non-coherent devices
based on them.
Of course not all cores will support this, so implement an
alternative-based mechanism that replaces empty instructions
with ones done around Zicbom instructions.
As discussed in previous versions, assume the platform
being coherent by default so that non-coherent devices need
to get marked accordingly by firmware.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20220706231536.2041855-4-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Currently, riscv has several extensions which may not be supported on
all riscv platforms, for example, FPU and so on. To support unified
kernel Image style, we need to check whether the feature is supported
or not. If the check sits at hot code path, then performance will be
impacted a lot. static key can be used to solve the issue. In the past,
FPU support has been converted to use static key mechanism. I believe
we will have similar cases in the future.
This patch tries to add an unified mechanism to use static keys for
some ISA extensions by implementing an array of default-false static keys
and enabling them when detected.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20220522153543.2656-2-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Svpbmt (the S should be capitalized) is the
"Supervisor-mode: page-based memory types" extension
that specifies attributes for cacheability, idempotency
and ordering.
The relevant settings are done in special bits in PTEs:
Here is the svpbmt PTE format:
| 63 | 62-61 | 60-8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
N MT RSW D A G U X W R V
^
Of the Reserved bits [63:54] in a leaf PTE, the high bit is already
allocated (as the N bit), so bits [62:61] are used as the MT (aka
MemType) field. This field specifies one of three memory types that
are close equivalents (or equivalent in effect) to the three main x86
and ARMv8 memory types - as shown in the following table.
RISC-V
Encoding &
MemType RISC-V Description
---------- ------------------------------------------------
00 - PMA Normal Cacheable, No change to implied PMA memory type
01 - NC Non-cacheable, idempotent, weakly-ordered Main Memory
10 - IO Non-cacheable, non-idempotent, strongly-ordered I/O memory
11 - Rsvd Reserved for future standard use
As the extension will not be present on all implementations,
implement a method to handle cpufeatures via alternatives
to not incur runtime penalties on cpu variants not supporting
specific extensions and patch relevant code parts at runtime.
Co-developed-by: Wei Fu <wefu@redhat.com>
Signed-off-by: Wei Fu <wefu@redhat.com>
Co-developed-by: Liu Shaohua <liush@allwinnertech.com>
Signed-off-by: Liu Shaohua <liush@allwinnertech.com>
Co-developed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
[moved to use the alternatives mechanism]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Link: https://lore.kernel.org/r/20220511192921.2223629-10-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The sscofpmf extension allows counter overflow and filtering for
programmable counters. Enable the perf driver to handle the overflow
interrupt. The overflow interrupt is a hart local interrupt.
Thus, per cpu overflow interrupts are setup as a child under the root
INTC irq domain.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Currently, the /proc/cpuinfo outputs the entire riscv,isa string which
is not ideal when we have multiple ISA extensions present in the ISA
string. Some of them may not be enabled in kernel as well.
Same goes for the single letter extensions as well which prints the
entire ISA string. Some of they may not be valid ISA extensions as
well (e.g 'su')
Parse only the valid & enabled ISA extension and print them.
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Multi-letter extensions can be probed using exising
riscv_isa_extension_available API now. It doesn't support versioning
right now as there is no use case for it.
Individual extension specific implementation will be added during
each extension support.
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This patch adds riscv_isa bitmap which represents Host ISA features
common across all Host CPUs. The riscv_isa is not same as elf_hwcap
because elf_hwcap will only have ISA features relevant for user-space
apps whereas riscv_isa will have ISA features relevant to both kernel
and user-space apps.
One of the use-case for riscv_isa bitmap is in KVM hypervisor where
we will use it to do following operations:
1. Check whether hypervisor extension is available
2. Find ISA features that need to be virtualized (e.g. floating
point support, vector extension, etc.)
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
There are many different formats in each header now, such as
_ASM_XXX_H, __ASM_XXX_H, _ASM_RISCV_XXX_H, RISCV_XXX_H, etc., This patch
tries to unify the format by using _ASM_RISCV_XXX_H, because the most
header use it now. This patch also adds the conditional to the headers
if they lost it.
Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 503 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch contains the code that interfaces with ELF objects on RISC-V
systems, the vast majority of which is present to load kernel modules.
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
