Hi, On Fri, Nov 24, 2023 at 08:21:37AM +0100, Christoph Muellner wrote: > From: Christoph Müllner <christoph.muellner@xxxxxxxx> > > The upcoming RISC-V Ssdtso specification introduces a bit in the senvcfg > CSR to switch the memory consistency model at run-time from RVWMO to TSO > (and back). The active consistency model can therefore be switched on a > per-hart base and managed by the kernel on a per-process/thread base. > > This patch implements basic Ssdtso support and adds a prctl API on top > so that user-space processes can switch to a stronger memory consistency > model (than the kernel was written for) at run-time. > > I am not sure if other architectures support switching the memory > consistency model at run-time, but designing the prctl API in an > arch-independent way allows reusing it in the future. > > The patchset also comes with a short documentation of the prctl API. > > This series is based on the second draft of the Ssdtso specification > which was published recently on an RVI list: > https://lists.riscv.org/g/tech-arch-review/message/183 > Note, that the Ssdtso specification is in development state > (i.e., not frozen or even ratified) which is also the reason > why I marked the series as RFC. > > One aspect that is not covered in this patchset is virtualization. > It is planned to add virtualization support in a later version. > Hints/suggestions on how to implement this part are very much > appreciated. > > Christoph Müllner (5): I know this is an RFC, but it could probably do with a bit more compile testing, as: > RISC-V: Add basic Ssdtso support This patch doesn't build for rv64 allmodconfig > RISC-V: Expose Ssdtso via hwprobe API This one seems to build fine > uapi: prctl: Add new prctl call to set/get the memory consistency > model > RISC-V: Implement prctl call to set/get the memory consistency model > RISC-V: selftests: Add DTSO tests These don't build for: rv32 defconfig rv64 allmodconfig rv64 nommu Cheers, Conor.
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