[PATCH v16 0/9] RISC-V IPI Improvements
Anup Patel
apatel at ventanamicro.com
Thu Jan 19 19:29:47 PST 2023
Hi Marc,
On Thu, Jan 12, 2023 at 5:47 PM Anup Patel <apatel at ventanamicro.com> wrote:
>
> Hi Marc,
>
> On Tue, Jan 3, 2023 at 7:42 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) Linux RISC-V SWI support
> >
> > These patches can also be found in riscv_ipi_imp_v16 branch at:
> > https://github.com/avpatel/linux.git
> >
> > Changes since v15:
> > - Rebased on Linux-6.2-rc2
> > - Added Reviewed-by and Tested-by tags to some of the patches.
> >
> > Changes since v14:
> > - Minor fixes in commit description of PATCH3 (as suggested by tglx)
> > - Don't disable parent IPI when CPU goes offline for SBI IPI driver and
> > CLINT driver in PATCH4.
> > - Include Apple AIC driver changes from Marc Z as PATCH9
> >
> > Changes since v13:
> > - Included changes suggested by Marc Z in PATCH3
> > - Use chained handlers in PATCH4
> > - Added new PATCH8 to have empty irq_eoi() in RISC-V INTC driver. This
> > avoids the unnecessary mask/unmask dance at time of handling interrupts.
> >
> > Changes since v12:
> > - Rebased on Linux-6.1-rc7
> > - Bring-back the IPI optimization in ipi_mux_send_mask() for PATCH3
> > - Call ipi_mux_send() for one target CPU at a time in PATCH3
> >
> > Changes since v11:
> > - Removed ipi_mux_pre/post_handle() callbacks in PATCH3
> > - Removed sturct ipi_mux_ops in PATCH3
> > - Removed parent_virq and data pointer from everywhere in PATCH3
> > - Removed struct ipi_mux_control in PATCH3
> > - Improved function signature of ipi_mux_send() callback in PATCH3
> > - Used unsigned type with atomic operation in PATCH3
> >
> > Changes since v10:
> > - Rebased on Linux-6.1-rc5
> > - Drop the "!(pending & ibit)" check in ipi_mux_send_mask() of PATCH3
> > - Disable local interrupts in ipi_mux_send_mask() of PATCH3 because we
> > can be preempted while using a per-CPU temporary variable.
> >
> > Changes since v9:
> > - Rebased on Linux-6.1-rc3
> > - Updated header comment block of ipi-mux.c in PATCH3
> > - Use a struct for global data of ipi-mux.c in PATCH3
> > - Add per-CPU temp cpumask for sending IPIs in PATCH3
> > - Drop the use of fwspec in PATCH3
> > - Use static key for ipi_mux_pre_handle() and ipi_mux_post_handle()
> > in PATCH3
> > - Remove redundant pr_warn_ratelimited() called by ipi_mux_process()
> > in PATCH3
> > - Remove CPUHP thingy from ipi_mux_create() in PATCH3
> >
> > Changes since v8:
> > - Rebased on Linux-6.0-rc3
> > - Use dummy percpu data as parameter for request_percpu_irq() in PATCH4.
> >
> > Changes since v7:
> > - Rebased on Linux-6.0-rc1
> > - Use atomic operations to track per-CPU pending and enabled IPIs in PATCH3.
> > (Note: this is inspired from IPI muxing implemented in
> > drivers/irqchip/irq-apple-aic.c)
> > - Made "struct ipi_mux_ops" (added by PATCH3) flexible so that
> > drivers/irqchip/irq-apple-aic.c can adopt it in future.
> >
> > Changes since v6:
> > - Rebased on Linux-5.19-rc7
> > - Added documentation for struct ipi_mux_ops in PATCH3
> > - Dropped dummy irq_mask()/unmask() in PATCH3
> > - Added const for "ipi_mux_chip" in PATCH3
> > - Removed "type" initialization from ipi_mux_domain_alloc() in PATCH3
> > - Dropped translate() from "ipi_mux_domain_ops" in PATCH3
> > - Improved barrier documentation in ipi_mux_process() of PATCH3
> > - Added percpu check in ipi_mux_create() for parent_virq of PATCH3
> > - Added nr_ipi parameter in ipi_mux_create() of PATCH3
> >
> > 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 (8):
> > 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
> > irqchip/riscv-intc: Add empty irq_eoi() for chained irq handlers
> >
> > Marc Zyngier (1):
> > irqchip/apple-aic: Move over to core ipi-mux
> >
> > arch/riscv/Kconfig | 2 +
> > arch/riscv/include/asm/irq.h | 4 +
> > arch/riscv/include/asm/sbi.h | 9 +-
> > 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 | 77 +++++++++++
> > arch/riscv/kernel/sbi.c | 100 +++------------
> > arch/riscv/kernel/smp.c | 171 ++++++++++++------------
> > arch/riscv/kernel/smpboot.c | 5 +-
> > arch/riscv/mm/cacheflush.c | 5 +-
> > arch/riscv/mm/tlbflush.c | 93 +++++++++++---
> > drivers/clocksource/timer-clint.c | 65 +++++++---
> > drivers/irqchip/Kconfig | 2 +
> > drivers/irqchip/irq-apple-aic.c | 161 ++---------------------
> > drivers/irqchip/irq-riscv-intc.c | 71 ++++++----
> > include/linux/irq.h | 3 +
> > kernel/irq/Kconfig | 5 +
> > kernel/irq/Makefile | 1 +
> > kernel/irq/ipi-mux.c | 207 ++++++++++++++++++++++++++++++
> > 21 files changed, 654 insertions(+), 401 deletions(-)
> > create mode 100644 arch/riscv/kernel/sbi-ipi.c
> > create mode 100644 kernel/irq/ipi-mux.c
> >
> > --
> > 2.34.1
> >
>
> Friendly ping ?
Any further comments on this series ?
Regards,
Anup
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