[PATCH v6 0/7] RISC-V IPI Improvements

[Anup Patel]

Hi Marc and Thomas,

Just a friendly ping ...

On Mon, Apr 18, 2022 at 4:23 PM Anup Patel <apatel at ventanamicro.com> wrote:
>
> This series aims to improve IPI support in Linux RISC-V in following ways:
>  1) Treat IPIs as normal per-CPU interrupts instead of having custom RISC-V
>     specific hooks. This also makes Linux RISC-V IPI support aligned with
>     other architectures.
>  2) Remote TLB flushes and icache flushes should prefer local IPIs instead
>     of SBI calls whenever we have specialized hardware (such as RISC-V AIA
>     IMSIC and RISC-V SWI) which allows S-mode software to directly inject
>     IPIs without any assistance from M-mode runtime firmware.
>
> These patches were originally part of the "Linux RISC-V ACLINT Support"
> series but this now a separate series so that it can be merged independently
> of the "Linux RISC-V ACLINT Support" series.
> (Refer, https://lore.kernel.org/lkml/20211007123632.697666-1-anup.patel@wdc.com/)
>
> These patches are also a preparatory patches for the up-coming:
>  1) Linux RISC-V AIA support
>  2) KVM RISC-V TLB flush improvements
>  3) Linux RISC-V SWI support
>
> These patches can also be found in riscv_ipi_imp_v6 branch at:
> https://github.com/avpatel/linux.git
>
> Changes since v5:
>  - Rebased on Linux-5.18-rc3
>  - Used kernel doc style in PATCH3
>  - Removed redundant loop in ipi_mux_process() of PATCH3
>  - Removed "RISC-V" prefix form ipi_mux_chip.name of PATCH3
>  - Removed use of "this patch" in PATCH3 commit description
>  - Addressed few other nit comments in PATCH3
>
> Changes since v4:
>  - Rebased on Linux-5.17
>  - Includes new PATCH3 which adds mechanism to multiplex a single HW IPI
>
> Changes since v3:
>  - Rebased on Linux-5.17-rc6
>  - Updated PATCH2 to not export riscv_set_intc_hwnode_fn()
>  - Simplified riscv_intc_hwnode() in PATCH2
>
> Changes since v2:
>  - Rebased on Linux-5.17-rc4
>  - Updated PATCH2 to not create synthetic INTC fwnode and instead provide
>    a function which allows drivers to directly discover INTC fwnode
>
> Changes since v1:
>  - Use synthetic fwnode for INTC instead of irq_set_default_host() in PATCH2
>
> Anup Patel (7):
>   RISC-V: Clear SIP bit only when using SBI IPI operations
>   irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode
>   genirq: Add mechanism to multiplex a single HW IPI
>   RISC-V: Treat IPIs as normal Linux IRQs
>   RISC-V: Allow marking IPIs as suitable for remote FENCEs
>   RISC-V: Use IPIs for remote TLB flush when possible
>   RISC-V: Use IPIs for remote icache flush when possible

Any further comments on this series ?

Regards,
Anup

>
>  arch/riscv/Kconfig                |   2 +
>  arch/riscv/include/asm/irq.h      |   4 +
>  arch/riscv/include/asm/sbi.h      |   2 +
>  arch/riscv/include/asm/smp.h      |  49 +++++---
>  arch/riscv/kernel/Makefile        |   1 +
>  arch/riscv/kernel/cpu-hotplug.c   |   3 +-
>  arch/riscv/kernel/irq.c           |  21 +++-
>  arch/riscv/kernel/sbi-ipi.c       |  60 +++++++++
>  arch/riscv/kernel/sbi.c           |  11 --
>  arch/riscv/kernel/smp.c           | 164 +++++++++++++------------
>  arch/riscv/kernel/smpboot.c       |   5 +-
>  arch/riscv/mm/cacheflush.c        |   5 +-
>  arch/riscv/mm/tlbflush.c          |  93 +++++++++++---
>  drivers/clocksource/timer-clint.c |  41 +++++--
>  drivers/irqchip/irq-riscv-intc.c  |  60 ++++-----
>  include/linux/irq.h               |  11 ++
>  kernel/irq/Kconfig                |   4 +
>  kernel/irq/Makefile               |   1 +
>  kernel/irq/ipi-mux.c              | 197 ++++++++++++++++++++++++++++++
>  19 files changed, 567 insertions(+), 167 deletions(-)
>  create mode 100644 arch/riscv/kernel/sbi-ipi.c
>  create mode 100644 kernel/irq/ipi-mux.c
>
> --
> 2.25.1
>