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2022-08-12RISC-V: Add Sstc extension supportPalmer Dabbelt1-0/+5
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
2022-08-12RISC-V: Add SSTC extension CSR detailsAtish Patra1-0/+5
This patch just introduces the required CSR fields related to the SSTC extension. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20220722165047.519994-2-atishp@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-07-29RISC-V: KVM: Add support for Svpbmt inside Guest/VMAnup Patel1-0/+16
The Guest/VM can use Svpbmt in VS-stage page tables when allowed by the Hypervisor using the henvcfg.PBMTE bit. We add Svpbmt support for the KVM Guest/VM which can be enabled/disabled by the KVM user-space (QEMU/KVMTOOL) using the ISA extension ONE_REG interface. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-06-01Merge tag 'riscv-for-linus-5.19-mw0' of ↵Linus Torvalds1-0/+7
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull RISC-V updates from Palmer Dabbelt: - Support for the Svpbmt extension, which allows memory attributes to be encoded in pages - Support for the Allwinner D1's implementation of page-based memory attributes - Support for running rv32 binaries on rv64 systems, via the compat subsystem - Support for kexec_file() - Support for the new generic ticket-based spinlocks, which allows us to also move to qrwlock. These should have already gone in through the asm-geneic tree as well - A handful of cleanups and fixes, include some larger ones around atomics and XIP * tag 'riscv-for-linus-5.19-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (51 commits) RISC-V: Prepare dropping week attribute from arch_kexec_apply_relocations[_add] riscv: compat: Using seperated vdso_maps for compat_vdso_info RISC-V: Fix the XIP build RISC-V: Split out the XIP fixups into their own file RISC-V: ignore xipImage RISC-V: Avoid empty create_*_mapping definitions riscv: Don't output a bogus mmu-type on a no MMU kernel riscv: atomic: Add custom conditional atomic operation implementation riscv: atomic: Optimize dec_if_positive functions riscv: atomic: Cleanup unnecessary definition RISC-V: Load purgatory in kexec_file RISC-V: Add purgatory RISC-V: Support for kexec_file on panic RISC-V: Add kexec_file support RISC-V: use memcpy for kexec_file mode kexec_file: Fix kexec_file.c build error for riscv platform riscv: compat: Add COMPAT Kbuild skeletal support riscv: compat: ptrace: Add compat_arch_ptrace implement riscv: compat: signal: Add rt_frame implementation riscv: add memory-type errata for T-Head ...
2022-05-20RISC-V: KVM: Add Sv57x4 mode support for G-stageAnup Patel1-0/+1
Latest QEMU supports G-stage Sv57x4 mode so this patch extends KVM RISC-V G-stage handling to detect and use Sv57x4 mode when available. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-04-26riscv: compat: syscall: Add entry.S implementationGuo Ren1-0/+7
Implement the entry of compat_sys_call_table[] in asm. Ref to riscv-privileged spec 4.1.1 Supervisor Status Register (sstatus): BIT[32:33] = UXL[1:0]: - 1:32 - 2:64 - 3:128 Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Tested-by: Heiko Stuebner <heiko@sntech.de> Link: https://lore.kernel.org/r/20220405071314.3225832-13-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-03-22perf: RISC-V: Add support for SBI PMU and SscofpmfPalmer Dabbelt1-1/+65
This series improves perf support for RISC-V based system using SBI PMU and Sscofpmf extensions, by adding a new generic RISC-V perf framework along with a pair of drivers: one that usese the new performance-monitoring extensions and one that keeps support for the existing systems that only have the legacy counters. Tested-by: Nikita Shubin <n.shubin@yadro.com> * palmer/riscv-pmu: MAINTAINERS: Add entry for RISC-V PMU drivers Documentation: riscv: Remove the old documentation RISC-V: Add sscofpmf extension support RISC-V: Add perf platform driver based on SBI PMU extension RISC-V: Add RISC-V SBI PMU extension definitions RISC-V: Add a simple platform driver for RISC-V legacy perf RISC-V: Add a perf core library for pmu drivers RISC-V: Add CSR encodings for all HPMCOUNTERS RISC-V: Remove the current perf implementation
2022-03-22RISC-V: Add sscofpmf extension supportAtish Patra1-1/+7
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>
2022-03-22RISC-V: Add CSR encodings for all HPMCOUNTERSAtish Patra1-0/+58
Linux kernel can directly read these counters as the HPMCOUNTERS CSRs are accessible in S-mode. Reviewed-by: Anup Patel <anup@brainfault.org> 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>
2022-02-15riscv: mm: Set sv57 on defaultlyQinglin Pan1-0/+1
This patch sets sv57 on defaultly if CONFIG_64BIT. And do fallback to try to set sv48 on boot time if sv57 is not supported in current hardware. Signed-off-by: Qinglin Pan <panqinglin2020@iscas.ac.cn> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-01-20riscv: Implement sv48 supportAlexandre Ghiti1-2/+1
By adding a new 4th level of page table, give the possibility to 64bit kernel to address 2^48 bytes of virtual address: in practice, that offers 128TB of virtual address space to userspace and allows up to 64TB of physical memory. If the underlying hardware does not support sv48, we will automatically fallback to a standard 3-level page table by folding the new PUD level into PGDIR level. In order to detect HW capabilities at runtime, we use SATP feature that ignores writes with an unsupported mode. Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2021-10-04RISC-V: Add hypervisor extension related CSR definesAnup Patel1-0/+87
This patch adds asm/kvm_csr.h for RISC-V hypervisor extension related defines. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alexander Graf <graf@amazon.com> Message-Id: <20210927114016.1089328-2-anup.patel@wdc.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-26riscv: Introduce alternative mechanism to apply errata solutionVincent Chen1-0/+3
Introduce the "alternative" mechanism from ARM64 and x86 to apply the CPU vendors' errata solution at runtime. The main purpose of this patch is to provide a framework. Therefore, the implementation is quite basic for now so that some scenarios could not use this schemei, such as patching code to a module, relocating the patching code and heterogeneous CPU topology. Users could use the macro ALTERNATIVE to apply an errata to the existing code flow. In the macro ALTERNATIVE, users need to specify the manufacturer information(vendorid, archid, and impid) for this errata. Therefore, kernel will know this errata is suitable for which CPU core. During the booting procedure, kernel will select the errata required by the CPU core and then patch it. It means that the kernel only applies the errata to the specified CPU core. In this case, the vendor's errata does not affect each other at runtime. The above patching procedure only occurs during the booting phase, so we only take the overhead of the "alternative" mechanism once. This "alternative" mechanism is enabled by default to ensure that all required errata will be applied. However, users can disable this feature by the Kconfig "CONFIG_RISCV_ERRATA_ALTERNATIVE". Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-02-19RISC-V: Implement ASID allocatorAnup Patel1-0/+6
Currently, we do local TLB flush on every MM switch. This is very harsh on performance because we are forcing page table walks after every MM switch. This patch implements ASID allocator for assigning an ASID to a MM context. The number of ASIDs are limited in HW so we create a logical entity named CONTEXTID for assigning to MM context. The lower bits of CONTEXTID are ASID and upper bits are VERSION number. The number of usable ASID bits supported by HW are detected at boot-time by writing 1s to ASID bits in SATP CSR. We allocate new CONTEXTID on first MM switch for a MM context where the ASID is allocated from an ASID bitmap and VERSION is provide by an atomic counter. At time of allocating new CONTEXTID, if we run out of available ASIDs then: 1. We flush the ASID bitmap 2. Increment current VERSION atomic counter 3. Re-allocate ASID from ASID bitmap 4. Flush TLB on all CPUs 5. Try CONTEXTID re-assignment on all CPUs Please note that we don't use ASID #0 because it is used at boot-time by all CPUs for initial MM context. Also, newly created context is always assigned CONTEXTID #0 (i.e. VERSION #0 and ASID #0) which is an invalid context in our implementation. Using above approach, we have virtually infinite CONTEXTIDs on-top-of limited number of HW ASIDs. This approach is inspired from ASID allocator used for Linux ARM/ARM64 but we have adapted it for RISC-V. Overall, this ASID allocator helps us reduce rate of local TLB flushes on every CPU thereby increasing performance. This patch is tested on QEMU virt machine, Spike and SiFive Unleashed board. On QEMU virt machine, we see some (3-5% approx) performance improvement with SW emulated TLBs provided by QEMU. Unfortunately, the ASID bits of the SATP CSR are not implemented on Spike and SiFive Unleashed board so we don't see any change in performance. On real HW having all ASID bits implemented, the performance gains will be much more due improved sharing of TLB among different processes. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-05-05RISC-V: Remove N-extension related definesAnup Patel1-3/+0
The RISC-V N-extension is still in draft state hence remove N-extension related defines from asm/csr.h. Signed-off-by: Anup Patel <anup.patel@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-02-18riscv: set pmp configuration if kernel is running in M-modeGreentime Hu1-0/+12
When the kernel is running in S-mode, the expectation is that the bootloader or SBI layer will configure the PMP to allow the kernel to access physical memory. But, when the kernel is running in M-mode and is started with the ELF "loader", there's probably no bootloader or SBI layer involved to configure the PMP. Thus, we need to configure the PMP ourselves to enable the kernel to access all regions. Signed-off-by: Greentime Hu <greentime.hu@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-01-05riscv: prefix IRQ_ macro names with an RV_ namespacePaul Walmsley1-9/+9
"IRQ_TIMER", used in the arch/riscv CSR header file, is a sufficiently generic macro name that it's used by several source files across the Linux code base. Some of these other files ultimately include the arch/riscv CSR include file, causing collisions. Fix by prefixing the RISC-V csr.h IRQ_ macro names with an RV_ prefix. Fixes: a4c3733d32a72 ("riscv: abstract out CSR names for supervisor vs machine mode") Reported-by: Olof Johansson <olof@lixom.net> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-18riscv: clear the instruction cache and all registers when bootingChristoph Hellwig1-0/+1
When we get booted we want a clear slate without any leaks from previous supervisors or the firmware. Flush the instruction cache and then clear all registers to known good values. This is really important for the upcoming nommu support that runs on M-mode, but can't really harm when running in S-mode either. Vaguely based on the concepts from opensbi. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-18riscv: read the hart ID from mhartid on bootDamien Le Moal1-0/+1
When in M-Mode, we can use the mhartid CSR to get the ID of the running HART. Doing so, direct M-Mode boot without firmware is possible. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-05riscv: abstract out CSR names for supervisor vs machine modeChristoph Hellwig1-10/+62
Many of the privileged CSRs exist in a supervisor and machine version that are used very similarly. Provide versions of the CSR names and fields that map to either the S-mode or M-mode variant depending on a new CONFIG_RISCV_M_MODE kconfig symbol. Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com> and Paul Walmsley <paul.walmsley@sifive.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> # for drivers/clocksource, drivers/irqchip [paul.walmsley@sifive.com: updated to apply] Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286Thomas Gleixner1-9/+1
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 as published by the free software foundation version 2 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 97 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.025053186@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-17RISC-V: Access CSRs using CSR numbersAnup Patel1-7/+25
We should prefer accessing CSRs using their CSR numbers because: 1. It compiles fine with older toolchains. 2. We can use latest CSR names in #define macro names of CSR numbers as-per RISC-V spec. 3. We can access newly added CSRs even if toolchain does not recognize newly addes CSRs by name. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-05-17RISC-V: Add interrupt related SCAUSE defines in asm/csr.hAnup Patel1-4/+17
This patch adds SCAUSE interrupt flag and SCAUSE interrupt related defines to asm/csr.h. We also use these defines in kernel/irq.c and express SIE/SIP flags in-terms of SCAUSE interrupt causes. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-05-17RISC-V: Use tabs to align macro values in asm/csr.hAnup Patel1-38/+38
The spacing between macro name and value is not consistent in asm/csr.h. This patch beautifies asm/csr.h by using tabs to align macro values instead of spaces. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-08-13RISC-V: add a definition for the SIE SEIE bitChristoph Hellwig1-0/+1
This mirrors the SIE_SSIE and SETE bits that are used in a similar fashion. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-01-31riscv: rename sptbr to satpChristoph Hellwig1-7/+7
satp is the name used by the current privileged spec 1.10, use it instead of the old name. The most recent release binutils release (2.29) doesn't know about the satp name yet, so stick to the name from the previous privileged ISA release and comment on the fact. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-01-08riscv: rename SR_* constants to match the specChristoph Hellwig1-4/+4
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2017-09-27RISC-V: Generic library routines and assemblyPalmer Dabbelt1-0/+132
This patch contains code that is more specific to the RISC-V ISA than it is to Linux. It contains string and math operations, C wrappers for various assembly instructions, stack walking code, and uaccess. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
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