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* [PATCH v18 0/7] RISC-V IPI Improvements
@ 2023-03-28  3:52 Anup Patel
  2023-03-28  3:52 ` [PATCH v18 1/7] RISC-V: Clear SIP bit only when using SBI IPI operations Anup Patel
                   ` (8 more replies)
  0 siblings, 9 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel

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_v18 branch at:
https://github.com/avpatel/linux.git

Changes since v17:
 - Resolved merge conflicts and rebased on Linux-6.3-rc4

Changes since v16:
 - Rebased on Linux-6.3-rc1
 - Dropped PATCH3 and PATCH9 since these patches are already merged
 - Added Palmer's Acked-by

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 (7):
  RISC-V: Clear SIP bit only when using SBI IPI operations
  irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode
  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

 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           |   1 +
 drivers/irqchip/irq-riscv-intc.c  |  71 ++++++++-----
 16 files changed, 429 insertions(+), 248 deletions(-)
 create mode 100644 arch/riscv/kernel/sbi-ipi.c

-- 
2.34.1


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^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH v18 1/7] RISC-V: Clear SIP bit only when using SBI IPI operations
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
@ 2023-03-28  3:52 ` Anup Patel
  2023-03-28  3:52 ` [PATCH v18 2/7] irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode Anup Patel
                   ` (7 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel, Bin Meng, Atish Patra, Palmer Dabbelt

The software interrupt pending (i.e. [M|S]SIP) bit is writeable for
S-mode but read-only for M-mode so we clear this bit only when using
SBI IPI operations.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/kernel/sbi.c | 8 +++++++-
 arch/riscv/kernel/smp.c | 2 --
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 5c87db8fdff2..ac99a70ead6a 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -646,8 +646,14 @@ static void sbi_send_cpumask_ipi(const struct cpumask *target)
 	sbi_send_ipi(target);
 }
 
+static void sbi_ipi_clear(void)
+{
+	csr_clear(CSR_IP, IE_SIE);
+}
+
 static const struct riscv_ipi_ops sbi_ipi_ops = {
-	.ipi_inject = sbi_send_cpumask_ipi
+	.ipi_inject = sbi_send_cpumask_ipi,
+	.ipi_clear = sbi_ipi_clear
 };
 
 void __init sbi_init(void)
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 8c3b59f1f9b8..8a12768c09ee 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -112,8 +112,6 @@ void riscv_clear_ipi(void)
 {
 	if (ipi_ops && ipi_ops->ipi_clear)
 		ipi_ops->ipi_clear();
-
-	csr_clear(CSR_IP, IE_SIE);
 }
 EXPORT_SYMBOL_GPL(riscv_clear_ipi);
 
-- 
2.34.1


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^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH v18 2/7] irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
  2023-03-28  3:52 ` [PATCH v18 1/7] RISC-V: Clear SIP bit only when using SBI IPI operations Anup Patel
@ 2023-03-28  3:52 ` Anup Patel
  2023-03-28  3:52 ` [PATCH v18 3/7] RISC-V: Treat IPIs as normal Linux IRQs Anup Patel
                   ` (6 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel, Atish Patra, Palmer Dabbelt

Various RISC-V drivers (such as SBI IPI, SBI Timer, SBI PMU, and
KVM RISC-V) don't have associated DT node but these drivers need
standard per-CPU (local) interrupts defined by the RISC-V privileged
specification.

We add riscv_get_intc_hwnode() in arch/riscv which allows RISC-V
drivers not having DT node to discover INTC hwnode which in-turn
helps these drivers to map per-CPU (local) interrupts provided
by the INTC driver.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/include/asm/irq.h     |  4 ++++
 arch/riscv/kernel/irq.c          | 18 ++++++++++++++++++
 drivers/irqchip/irq-riscv-intc.c |  7 +++++++
 3 files changed, 29 insertions(+)

diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index e4c435509983..43b9ebfbd943 100644
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -12,6 +12,10 @@
 
 #include <asm-generic/irq.h>
 
+void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void));
+
+struct fwnode_handle *riscv_get_intc_hwnode(void);
+
 extern void __init init_IRQ(void);
 
 #endif /* _ASM_RISCV_IRQ_H */
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 7207fa08d78f..96d3171f0ca1 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -7,9 +7,27 @@
 
 #include <linux/interrupt.h>
 #include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
 #include <linux/seq_file.h>
 #include <asm/smp.h>
 
+static struct fwnode_handle *(*__get_intc_node)(void);
+
+void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void))
+{
+	__get_intc_node = fn;
+}
+
+struct fwnode_handle *riscv_get_intc_hwnode(void)
+{
+	if (__get_intc_node)
+		return __get_intc_node();
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(riscv_get_intc_hwnode);
+
 int arch_show_interrupts(struct seq_file *p, int prec)
 {
 	show_ipi_stats(p, prec);
diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index 499e5f81b3fe..9066467e99e4 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -92,6 +92,11 @@ static const struct irq_domain_ops riscv_intc_domain_ops = {
 	.xlate	= irq_domain_xlate_onecell,
 };
 
+static struct fwnode_handle *riscv_intc_hwnode(void)
+{
+	return intc_domain->fwnode;
+}
+
 static int __init riscv_intc_init(struct device_node *node,
 				  struct device_node *parent)
 {
@@ -126,6 +131,8 @@ static int __init riscv_intc_init(struct device_node *node,
 		return rc;
 	}
 
+	riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
+
 	cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_STARTING,
 			  "irqchip/riscv/intc:starting",
 			  riscv_intc_cpu_starting,
-- 
2.34.1


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http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH v18 3/7] RISC-V: Treat IPIs as normal Linux IRQs
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
  2023-03-28  3:52 ` [PATCH v18 1/7] RISC-V: Clear SIP bit only when using SBI IPI operations Anup Patel
  2023-03-28  3:52 ` [PATCH v18 2/7] irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode Anup Patel
@ 2023-03-28  3:52 ` Anup Patel
  2023-03-28  3:52 ` [PATCH v18 4/7] RISC-V: Allow marking IPIs as suitable for remote FENCEs Anup Patel
                   ` (5 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel, Palmer Dabbelt

Currently, the RISC-V kernel provides arch specific hooks (i.e.
struct riscv_ipi_ops) to register IPI handling methods. The stats
gathering of IPIs is also arch specific in the RISC-V kernel.

Other architectures (such as ARM, ARM64, and MIPS) have moved away
from custom arch specific IPI handling methods. Currently, these
architectures have Linux irqchip drivers providing a range of Linux
IRQ numbers to be used as IPIs and IPI triggering is done using
generic IPI APIs. This approach allows architectures to treat IPIs
as normal Linux IRQs and IPI stats gathering is done by the generic
Linux IRQ subsystem.

We extend the RISC-V IPI handling as-per above approach so that arch
specific IPI handling methods (struct riscv_ipi_ops) can be removed
and the IPI handling is done through the Linux IRQ subsystem.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/Kconfig                |   2 +
 arch/riscv/include/asm/sbi.h      |   9 +-
 arch/riscv/include/asm/smp.h      |  35 ++++---
 arch/riscv/kernel/Makefile        |   1 +
 arch/riscv/kernel/cpu-hotplug.c   |   3 +-
 arch/riscv/kernel/irq.c           |   3 +-
 arch/riscv/kernel/sbi-ipi.c       |  77 ++++++++++++++
 arch/riscv/kernel/sbi.c           | 106 +++-----------------
 arch/riscv/kernel/smp.c           | 160 +++++++++++++++---------------
 arch/riscv/kernel/smpboot.c       |   5 +-
 drivers/clocksource/timer-clint.c |  65 +++++++++---
 drivers/irqchip/Kconfig           |   1 +
 drivers/irqchip/irq-riscv-intc.c  |  55 +++++-----
 13 files changed, 283 insertions(+), 239 deletions(-)
 create mode 100644 arch/riscv/kernel/sbi-ipi.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5b182d1c196c..b90be751651f 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -63,6 +63,8 @@ config RISCV
 	select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
 	select GENERIC_IDLE_POLL_SETUP
 	select GENERIC_IOREMAP if MMU
+	select GENERIC_IRQ_IPI if SMP
+	select GENERIC_IRQ_IPI_MUX if SMP
 	select GENERIC_IRQ_MULTI_HANDLER
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IRQ_SHOW_LEVEL
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 945b7be249c1..acab4410ef2a 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -271,8 +271,7 @@ long sbi_get_marchid(void);
 long sbi_get_mimpid(void);
 void sbi_set_timer(uint64_t stime_value);
 void sbi_shutdown(void);
-void sbi_clear_ipi(void);
-int sbi_send_ipi(const struct cpumask *cpu_mask);
+void sbi_send_ipi(unsigned int cpu);
 int sbi_remote_fence_i(const struct cpumask *cpu_mask);
 int sbi_remote_sfence_vma(const struct cpumask *cpu_mask,
 			   unsigned long start,
@@ -335,4 +334,10 @@ unsigned long riscv_cached_mvendorid(unsigned int cpu_id);
 unsigned long riscv_cached_marchid(unsigned int cpu_id);
 unsigned long riscv_cached_mimpid(unsigned int cpu_id);
 
+#if IS_ENABLED(CONFIG_SMP) && IS_ENABLED(CONFIG_RISCV_SBI)
+void sbi_ipi_init(void);
+#else
+static inline void sbi_ipi_init(void) { }
+#endif
+
 #endif /* _ASM_RISCV_SBI_H */
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 3831b638ecab..4fe7a8854c2e 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -15,11 +15,6 @@
 struct seq_file;
 extern unsigned long boot_cpu_hartid;
 
-struct riscv_ipi_ops {
-	void (*ipi_inject)(const struct cpumask *target);
-	void (*ipi_clear)(void);
-};
-
 #ifdef CONFIG_SMP
 /*
  * Mapping between linux logical cpu index and hartid.
@@ -33,9 +28,6 @@ void show_ipi_stats(struct seq_file *p, int prec);
 /* SMP initialization hook for setup_arch */
 void __init setup_smp(void);
 
-/* Called from C code, this handles an IPI. */
-void handle_IPI(struct pt_regs *regs);
-
 /* Hook for the generic smp_call_function_many() routine. */
 void arch_send_call_function_ipi_mask(struct cpumask *mask);
 
@@ -44,11 +36,17 @@ void arch_send_call_function_single_ipi(int cpu);
 
 int riscv_hartid_to_cpuid(unsigned long hartid);
 
-/* Set custom IPI operations */
-void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops);
+/* Enable IPI for CPU hotplug */
+void riscv_ipi_enable(void);
+
+/* Disable IPI for CPU hotplug */
+void riscv_ipi_disable(void);
 
-/* Clear IPI for current CPU */
-void riscv_clear_ipi(void);
+/* Check if IPI interrupt numbers are available */
+bool riscv_ipi_have_virq_range(void);
+
+/* Set the IPI interrupt numbers for arch (called by irqchip drivers) */
+void riscv_ipi_set_virq_range(int virq, int nr);
 
 /* Check other CPUs stop or not */
 bool smp_crash_stop_failed(void);
@@ -85,11 +83,20 @@ static inline unsigned long cpuid_to_hartid_map(int cpu)
 	return boot_cpu_hartid;
 }
 
-static inline void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops)
+static inline void riscv_ipi_enable(void)
 {
 }
 
-static inline void riscv_clear_ipi(void)
+static inline void riscv_ipi_disable(void)
+{
+}
+
+static inline bool riscv_ipi_have_virq_range(void)
+{
+	return false;
+}
+
+static inline void riscv_ipi_set_virq_range(int virq, int nr)
 {
 }
 
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 4cf303a779ab..67f542be1bea 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_PERF_EVENTS)	+= perf_callchain.o
 obj-$(CONFIG_HAVE_PERF_REGS)	+= perf_regs.o
 obj-$(CONFIG_RISCV_SBI)		+= sbi.o
 ifeq ($(CONFIG_RISCV_SBI), y)
+obj-$(CONFIG_SMP)		+= sbi-ipi.o
 obj-$(CONFIG_SMP) += cpu_ops_sbi.o
 endif
 obj-$(CONFIG_HOTPLUG_CPU)	+= cpu-hotplug.o
diff --git a/arch/riscv/kernel/cpu-hotplug.c b/arch/riscv/kernel/cpu-hotplug.c
index f7a832e3a1d1..39235cf50652 100644
--- a/arch/riscv/kernel/cpu-hotplug.c
+++ b/arch/riscv/kernel/cpu-hotplug.c
@@ -13,7 +13,7 @@
 #include <asm/irq.h>
 #include <asm/cpu_ops.h>
 #include <asm/numa.h>
-#include <asm/sbi.h>
+#include <asm/smp.h>
 
 bool cpu_has_hotplug(unsigned int cpu)
 {
@@ -43,6 +43,7 @@ int __cpu_disable(void)
 	remove_cpu_topology(cpu);
 	numa_remove_cpu(cpu);
 	set_cpu_online(cpu, false);
+	riscv_ipi_disable();
 	irq_migrate_all_off_this_cpu();
 
 	return ret;
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 96d3171f0ca1..eb9a68a539e6 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -10,7 +10,7 @@
 #include <linux/irqdomain.h>
 #include <linux/module.h>
 #include <linux/seq_file.h>
-#include <asm/smp.h>
+#include <asm/sbi.h>
 
 static struct fwnode_handle *(*__get_intc_node)(void);
 
@@ -39,4 +39,5 @@ void __init init_IRQ(void)
 	irqchip_init();
 	if (!handle_arch_irq)
 		panic("No interrupt controller found.");
+	sbi_ipi_init();
 }
diff --git a/arch/riscv/kernel/sbi-ipi.c b/arch/riscv/kernel/sbi-ipi.c
new file mode 100644
index 000000000000..41981ab88493
--- /dev/null
+++ b/arch/riscv/kernel/sbi-ipi.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Multiplex several IPIs over a single HW IPI.
+ *
+ * Copyright (c) 2022 Ventana Micro Systems Inc.
+ */
+
+#define pr_fmt(fmt) "riscv: " fmt
+#include <linux/cpu.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <asm/sbi.h>
+
+static int sbi_ipi_virq;
+
+static void sbi_ipi_handle(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+
+	chained_irq_enter(chip, desc);
+
+	csr_clear(CSR_IP, IE_SIE);
+	ipi_mux_process();
+
+	chained_irq_exit(chip, desc);
+}
+
+static int sbi_ipi_starting_cpu(unsigned int cpu)
+{
+	enable_percpu_irq(sbi_ipi_virq, irq_get_trigger_type(sbi_ipi_virq));
+	return 0;
+}
+
+void __init sbi_ipi_init(void)
+{
+	int virq;
+	struct irq_domain *domain;
+
+	if (riscv_ipi_have_virq_range())
+		return;
+
+	domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(),
+					  DOMAIN_BUS_ANY);
+	if (!domain) {
+		pr_err("unable to find INTC IRQ domain\n");
+		return;
+	}
+
+	sbi_ipi_virq = irq_create_mapping(domain, RV_IRQ_SOFT);
+	if (!sbi_ipi_virq) {
+		pr_err("unable to create INTC IRQ mapping\n");
+		return;
+	}
+
+	virq = ipi_mux_create(BITS_PER_BYTE, sbi_send_ipi);
+	if (virq <= 0) {
+		pr_err("unable to create muxed IPIs\n");
+		irq_dispose_mapping(sbi_ipi_virq);
+		return;
+	}
+
+	irq_set_chained_handler(sbi_ipi_virq, sbi_ipi_handle);
+
+	/*
+	 * Don't disable IPI when CPU goes offline because
+	 * the masking/unmasking of virtual IPIs is done
+	 * via generic IPI-Mux
+	 */
+	cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+			  "irqchip/sbi-ipi:starting",
+			  sbi_ipi_starting_cpu, NULL);
+
+	riscv_ipi_set_virq_range(virq, BITS_PER_BYTE);
+	pr_info("providing IPIs using SBI IPI extension\n");
+}
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index ac99a70ead6a..92b9b759ab3d 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -17,7 +17,7 @@ unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT;
 EXPORT_SYMBOL(sbi_spec_version);
 
 static void (*__sbi_set_timer)(uint64_t stime) __ro_after_init;
-static int (*__sbi_send_ipi)(const struct cpumask *cpu_mask) __ro_after_init;
+static void (*__sbi_send_ipi)(unsigned int cpu) __ro_after_init;
 static int (*__sbi_rfence)(int fid, const struct cpumask *cpu_mask,
 			   unsigned long start, unsigned long size,
 			   unsigned long arg4, unsigned long arg5) __ro_after_init;
@@ -130,17 +130,6 @@ void sbi_shutdown(void)
 }
 EXPORT_SYMBOL(sbi_shutdown);
 
-/**
- * sbi_clear_ipi() - Clear any pending IPIs for the calling hart.
- *
- * Return: None
- */
-void sbi_clear_ipi(void)
-{
-	sbi_ecall(SBI_EXT_0_1_CLEAR_IPI, 0, 0, 0, 0, 0, 0, 0);
-}
-EXPORT_SYMBOL(sbi_clear_ipi);
-
 /**
  * __sbi_set_timer_v01() - Program the timer for next timer event.
  * @stime_value: The value after which next timer event should fire.
@@ -157,17 +146,12 @@ static void __sbi_set_timer_v01(uint64_t stime_value)
 #endif
 }
 
-static int __sbi_send_ipi_v01(const struct cpumask *cpu_mask)
+static void __sbi_send_ipi_v01(unsigned int cpu)
 {
-	unsigned long hart_mask;
-
-	if (!cpu_mask || cpumask_empty(cpu_mask))
-		cpu_mask = cpu_online_mask;
-	hart_mask = __sbi_v01_cpumask_to_hartmask(cpu_mask);
-
+	unsigned long hart_mask =
+		__sbi_v01_cpumask_to_hartmask(cpumask_of(cpu));
 	sbi_ecall(SBI_EXT_0_1_SEND_IPI, 0, (unsigned long)(&hart_mask),
 		  0, 0, 0, 0, 0);
-	return 0;
 }
 
 static int __sbi_rfence_v01(int fid, const struct cpumask *cpu_mask,
@@ -216,12 +200,10 @@ static void __sbi_set_timer_v01(uint64_t stime_value)
 		sbi_major_version(), sbi_minor_version());
 }
 
-static int __sbi_send_ipi_v01(const struct cpumask *cpu_mask)
+static void __sbi_send_ipi_v01(unsigned int cpu)
 {
 	pr_warn("IPI extension is not available in SBI v%lu.%lu\n",
 		sbi_major_version(), sbi_minor_version());
-
-	return 0;
 }
 
 static int __sbi_rfence_v01(int fid, const struct cpumask *cpu_mask,
@@ -248,55 +230,18 @@ static void __sbi_set_timer_v02(uint64_t stime_value)
 #endif
 }
 
-static int __sbi_send_ipi_v02(const struct cpumask *cpu_mask)
+static void __sbi_send_ipi_v02(unsigned int cpu)
 {
-	unsigned long hartid, cpuid, hmask = 0, hbase = 0, htop = 0;
-	struct sbiret ret = {0};
 	int result;
+	struct sbiret ret = {0};
 
-	if (!cpu_mask || cpumask_empty(cpu_mask))
-		cpu_mask = cpu_online_mask;
-
-	for_each_cpu(cpuid, cpu_mask) {
-		hartid = cpuid_to_hartid_map(cpuid);
-		if (hmask) {
-			if (hartid + BITS_PER_LONG <= htop ||
-			    hbase + BITS_PER_LONG <= hartid) {
-				ret = sbi_ecall(SBI_EXT_IPI,
-						SBI_EXT_IPI_SEND_IPI, hmask,
-						hbase, 0, 0, 0, 0);
-				if (ret.error)
-					goto ecall_failed;
-				hmask = 0;
-			} else if (hartid < hbase) {
-				/* shift the mask to fit lower hartid */
-				hmask <<= hbase - hartid;
-				hbase = hartid;
-			}
-		}
-		if (!hmask) {
-			hbase = hartid;
-			htop = hartid;
-		} else if (hartid > htop) {
-			htop = hartid;
-		}
-		hmask |= BIT(hartid - hbase);
-	}
-
-	if (hmask) {
-		ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI,
-				hmask, hbase, 0, 0, 0, 0);
-		if (ret.error)
-			goto ecall_failed;
+	ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI,
+			1UL, cpuid_to_hartid_map(cpu), 0, 0, 0, 0);
+	if (ret.error) {
+		result = sbi_err_map_linux_errno(ret.error);
+		pr_err("%s: hbase = [%lu] failed (error [%d])\n",
+			__func__, cpuid_to_hartid_map(cpu), result);
 	}
-
-	return 0;
-
-ecall_failed:
-	result = sbi_err_map_linux_errno(ret.error);
-	pr_err("%s: hbase = [%lu] hmask = [0x%lx] failed (error [%d])\n",
-	       __func__, hbase, hmask, result);
-	return result;
 }
 
 static int __sbi_rfence_v02_call(unsigned long fid, unsigned long hmask,
@@ -410,13 +355,11 @@ void sbi_set_timer(uint64_t stime_value)
 
 /**
  * sbi_send_ipi() - Send an IPI to any hart.
- * @cpu_mask: A cpu mask containing all the target harts.
- *
- * Return: 0 on success, appropriate linux error code otherwise.
+ * @cpu: Logical id of the target CPU.
  */
-int sbi_send_ipi(const struct cpumask *cpu_mask)
+void sbi_send_ipi(unsigned int cpu)
 {
-	return __sbi_send_ipi(cpu_mask);
+	__sbi_send_ipi(cpu);
 }
 EXPORT_SYMBOL(sbi_send_ipi);
 
@@ -641,21 +584,6 @@ long sbi_get_mimpid(void)
 }
 EXPORT_SYMBOL_GPL(sbi_get_mimpid);
 
-static void sbi_send_cpumask_ipi(const struct cpumask *target)
-{
-	sbi_send_ipi(target);
-}
-
-static void sbi_ipi_clear(void)
-{
-	csr_clear(CSR_IP, IE_SIE);
-}
-
-static const struct riscv_ipi_ops sbi_ipi_ops = {
-	.ipi_inject = sbi_send_cpumask_ipi,
-	.ipi_clear = sbi_ipi_clear
-};
-
 void __init sbi_init(void)
 {
 	int ret;
@@ -702,6 +630,4 @@ void __init sbi_init(void)
 		__sbi_send_ipi	= __sbi_send_ipi_v01;
 		__sbi_rfence	= __sbi_rfence_v01;
 	}
-
-	riscv_set_ipi_ops(&sbi_ipi_ops);
 }
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 8a12768c09ee..47e7ecfedb4d 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -13,14 +13,15 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/kexec.h>
+#include <linux/percpu.h>
 #include <linux/profile.h>
 #include <linux/smp.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/delay.h>
+#include <linux/irq.h>
 #include <linux/irq_work.h>
 
-#include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
 #include <asm/cpu_ops.h>
@@ -44,11 +45,10 @@ void __init smp_setup_processor_id(void)
 	cpuid_to_hartid_map(0) = boot_cpu_hartid;
 }
 
-/* A collection of single bit ipi messages.  */
-static struct {
-	unsigned long stats[IPI_MAX] ____cacheline_aligned;
-	unsigned long bits ____cacheline_aligned;
-} ipi_data[NR_CPUS] __cacheline_aligned;
+static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
+static int ipi_virq_base __ro_after_init;
+static int nr_ipi __ro_after_init = IPI_MAX;
+static struct irq_desc *ipi_desc[IPI_MAX] __read_mostly;
 
 int riscv_hartid_to_cpuid(unsigned long hartid)
 {
@@ -100,46 +100,14 @@ static inline void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
 }
 #endif
 
-static const struct riscv_ipi_ops *ipi_ops __ro_after_init;
-
-void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops)
-{
-	ipi_ops = ops;
-}
-EXPORT_SYMBOL_GPL(riscv_set_ipi_ops);
-
-void riscv_clear_ipi(void)
-{
-	if (ipi_ops && ipi_ops->ipi_clear)
-		ipi_ops->ipi_clear();
-}
-EXPORT_SYMBOL_GPL(riscv_clear_ipi);
-
 static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
 {
-	int cpu;
-
-	smp_mb__before_atomic();
-	for_each_cpu(cpu, mask)
-		set_bit(op, &ipi_data[cpu].bits);
-	smp_mb__after_atomic();
-
-	if (ipi_ops && ipi_ops->ipi_inject)
-		ipi_ops->ipi_inject(mask);
-	else
-		pr_warn("SMP: IPI inject method not available\n");
+	__ipi_send_mask(ipi_desc[op], mask);
 }
 
 static void send_ipi_single(int cpu, enum ipi_message_type op)
 {
-	smp_mb__before_atomic();
-	set_bit(op, &ipi_data[cpu].bits);
-	smp_mb__after_atomic();
-
-	if (ipi_ops && ipi_ops->ipi_inject)
-		ipi_ops->ipi_inject(cpumask_of(cpu));
-	else
-		pr_warn("SMP: IPI inject method not available\n");
+	__ipi_send_mask(ipi_desc[op], cpumask_of(cpu));
 }
 
 #ifdef CONFIG_IRQ_WORK
@@ -149,59 +117,89 @@ void arch_irq_work_raise(void)
 }
 #endif
 
-void handle_IPI(struct pt_regs *regs)
+static irqreturn_t handle_IPI(int irq, void *data)
+{
+	int ipi = irq - ipi_virq_base;
+
+	switch (ipi) {
+	case IPI_RESCHEDULE:
+		scheduler_ipi();
+		break;
+	case IPI_CALL_FUNC:
+		generic_smp_call_function_interrupt();
+		break;
+	case IPI_CPU_STOP:
+		ipi_stop();
+		break;
+	case IPI_CPU_CRASH_STOP:
+		ipi_cpu_crash_stop(smp_processor_id(), get_irq_regs());
+		break;
+	case IPI_IRQ_WORK:
+		irq_work_run();
+		break;
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+	case IPI_TIMER:
+		tick_receive_broadcast();
+		break;
+#endif
+	default:
+		pr_warn("CPU%d: unhandled IPI%d\n", smp_processor_id(), ipi);
+		break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+void riscv_ipi_enable(void)
 {
-	unsigned int cpu = smp_processor_id();
-	unsigned long *pending_ipis = &ipi_data[cpu].bits;
-	unsigned long *stats = ipi_data[cpu].stats;
+	int i;
 
-	riscv_clear_ipi();
+	if (WARN_ON_ONCE(!ipi_virq_base))
+		return;
 
-	while (true) {
-		unsigned long ops;
+	for (i = 0; i < nr_ipi; i++)
+		enable_percpu_irq(ipi_virq_base + i, 0);
+}
 
-		/* Order bit clearing and data access. */
-		mb();
+void riscv_ipi_disable(void)
+{
+	int i;
 
-		ops = xchg(pending_ipis, 0);
-		if (ops == 0)
-			return;
+	if (WARN_ON_ONCE(!ipi_virq_base))
+		return;
 
-		if (ops & (1 << IPI_RESCHEDULE)) {
-			stats[IPI_RESCHEDULE]++;
-			scheduler_ipi();
-		}
+	for (i = 0; i < nr_ipi; i++)
+		disable_percpu_irq(ipi_virq_base + i);
+}
 
-		if (ops & (1 << IPI_CALL_FUNC)) {
-			stats[IPI_CALL_FUNC]++;
-			generic_smp_call_function_interrupt();
-		}
+bool riscv_ipi_have_virq_range(void)
+{
+	return (ipi_virq_base) ? true : false;
+}
 
-		if (ops & (1 << IPI_CPU_STOP)) {
-			stats[IPI_CPU_STOP]++;
-			ipi_stop();
-		}
+void riscv_ipi_set_virq_range(int virq, int nr)
+{
+	int i, err;
 
-		if (ops & (1 << IPI_CPU_CRASH_STOP)) {
-			ipi_cpu_crash_stop(cpu, get_irq_regs());
-		}
+	if (WARN_ON(ipi_virq_base))
+		return;
 
-		if (ops & (1 << IPI_IRQ_WORK)) {
-			stats[IPI_IRQ_WORK]++;
-			irq_work_run();
-		}
+	WARN_ON(nr < IPI_MAX);
+	nr_ipi = min(nr, IPI_MAX);
+	ipi_virq_base = virq;
 
-#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
-		if (ops & (1 << IPI_TIMER)) {
-			stats[IPI_TIMER]++;
-			tick_receive_broadcast();
-		}
-#endif
-		BUG_ON((ops >> IPI_MAX) != 0);
+	/* Request IPIs */
+	for (i = 0; i < nr_ipi; i++) {
+		err = request_percpu_irq(ipi_virq_base + i, handle_IPI,
+					 "IPI", &ipi_dummy_dev);
+		WARN_ON(err);
 
-		/* Order data access and bit testing. */
-		mb();
+		ipi_desc[i] = irq_to_desc(ipi_virq_base + i);
+		irq_set_status_flags(ipi_virq_base + i, IRQ_HIDDEN);
 	}
+
+	/* Enabled IPIs for boot CPU immediately */
+	riscv_ipi_enable();
 }
 
 static const char * const ipi_names[] = {
@@ -221,7 +219,7 @@ void show_ipi_stats(struct seq_file *p, int prec)
 		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
 			   prec >= 4 ? " " : "");
 		for_each_online_cpu(cpu)
-			seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]);
+			seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu));
 		seq_printf(p, " %s\n", ipi_names[i]);
 	}
 }
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index ddb2afba6d25..00b53913d4c6 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -30,7 +30,6 @@
 #include <asm/numa.h>
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
-#include <asm/sbi.h>
 #include <asm/smp.h>
 
 #include "head.h"
@@ -158,12 +157,12 @@ asmlinkage __visible void smp_callin(void)
 	struct mm_struct *mm = &init_mm;
 	unsigned int curr_cpuid = smp_processor_id();
 
-	riscv_clear_ipi();
-
 	/* All kernel threads share the same mm context.  */
 	mmgrab(mm);
 	current->active_mm = mm;
 
+	riscv_ipi_enable();
+
 	store_cpu_topology(curr_cpuid);
 	notify_cpu_starting(curr_cpuid);
 	numa_add_cpu(curr_cpuid);
diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
index 6cfe2ab73eb0..7ccc16dd6a76 100644
--- a/drivers/clocksource/timer-clint.c
+++ b/drivers/clocksource/timer-clint.c
@@ -17,6 +17,9 @@
 #include <linux/sched_clock.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
 #include <linux/of_irq.h>
 #include <linux/smp.h>
 #include <linux/timex.h>
@@ -31,6 +34,7 @@
 
 /* CLINT manages IPI and Timer for RISC-V M-mode  */
 static u32 __iomem *clint_ipi_base;
+static unsigned int clint_ipi_irq;
 static u64 __iomem *clint_timer_cmp;
 static u64 __iomem *clint_timer_val;
 static unsigned long clint_timer_freq;
@@ -41,12 +45,10 @@ u64 __iomem *clint_time_val;
 EXPORT_SYMBOL(clint_time_val);
 #endif
 
-static void clint_send_ipi(const struct cpumask *target)
+#ifdef CONFIG_SMP
+static void clint_send_ipi(unsigned int cpu)
 {
-	unsigned int cpu;
-
-	for_each_cpu(cpu, target)
-		writel(1, clint_ipi_base + cpuid_to_hartid_map(cpu));
+	writel(1, clint_ipi_base + cpuid_to_hartid_map(cpu));
 }
 
 static void clint_clear_ipi(void)
@@ -54,10 +56,18 @@ static void clint_clear_ipi(void)
 	writel(0, clint_ipi_base + cpuid_to_hartid_map(smp_processor_id()));
 }
 
-static struct riscv_ipi_ops clint_ipi_ops = {
-	.ipi_inject = clint_send_ipi,
-	.ipi_clear = clint_clear_ipi,
-};
+static void clint_ipi_interrupt(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+
+	chained_irq_enter(chip, desc);
+
+	clint_clear_ipi();
+	ipi_mux_process();
+
+	chained_irq_exit(chip, desc);
+}
+#endif
 
 #ifdef CONFIG_64BIT
 #define clint_get_cycles()	readq_relaxed(clint_timer_val)
@@ -125,12 +135,19 @@ static int clint_timer_starting_cpu(unsigned int cpu)
 
 	enable_percpu_irq(clint_timer_irq,
 			  irq_get_trigger_type(clint_timer_irq));
+	enable_percpu_irq(clint_ipi_irq,
+			  irq_get_trigger_type(clint_ipi_irq));
 	return 0;
 }
 
 static int clint_timer_dying_cpu(unsigned int cpu)
 {
 	disable_percpu_irq(clint_timer_irq);
+	/*
+	 * Don't disable IPI when CPU goes offline because
+	 * the masking/unmasking of virtual IPIs is done
+	 * via generic IPI-Mux
+	 */
 	return 0;
 }
 
@@ -170,6 +187,12 @@ static int __init clint_timer_init_dt(struct device_node *np)
 			return -ENODEV;
 		}
 
+		/* Find parent irq domain and map ipi irq */
+		if (!clint_ipi_irq &&
+		    oirq.args[0] == RV_IRQ_SOFT &&
+		    irq_find_host(oirq.np))
+			clint_ipi_irq = irq_of_parse_and_map(np, i);
+
 		/* Find parent irq domain and map timer irq */
 		if (!clint_timer_irq &&
 		    oirq.args[0] == RV_IRQ_TIMER &&
@@ -177,9 +200,9 @@ static int __init clint_timer_init_dt(struct device_node *np)
 			clint_timer_irq = irq_of_parse_and_map(np, i);
 	}
 
-	/* If CLINT timer irq not found then fail */
-	if (!clint_timer_irq) {
-		pr_err("%pOFP: timer irq not found\n", np);
+	/* If CLINT ipi or timer irq not found then fail */
+	if (!clint_ipi_irq || !clint_timer_irq) {
+		pr_err("%pOFP: ipi/timer irq not found\n", np);
 		return -ENODEV;
 	}
 
@@ -219,6 +242,19 @@ static int __init clint_timer_init_dt(struct device_node *np)
 		goto fail_iounmap;
 	}
 
+#ifdef CONFIG_SMP
+	rc = ipi_mux_create(BITS_PER_BYTE, clint_send_ipi);
+	if (rc <= 0) {
+		pr_err("unable to create muxed IPIs\n");
+		rc = (rc < 0) ? rc : -ENODEV;
+		goto fail_free_irq;
+	}
+
+	irq_set_chained_handler(clint_ipi_irq, clint_ipi_interrupt);
+	riscv_ipi_set_virq_range(rc, BITS_PER_BYTE);
+	clint_clear_ipi();
+#endif
+
 	rc = cpuhp_setup_state(CPUHP_AP_CLINT_TIMER_STARTING,
 				"clockevents/clint/timer:starting",
 				clint_timer_starting_cpu,
@@ -228,13 +264,10 @@ static int __init clint_timer_init_dt(struct device_node *np)
 		goto fail_free_irq;
 	}
 
-	riscv_set_ipi_ops(&clint_ipi_ops);
-	clint_clear_ipi();
-
 	return 0;
 
 fail_free_irq:
-	free_irq(clint_timer_irq, &clint_clock_event);
+	free_percpu_irq(clint_timer_irq, &clint_clock_event);
 fail_iounmap:
 	iounmap(base);
 	return rc;
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 7dc990eb2c9b..2758bfdc2f2c 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -535,6 +535,7 @@ config TI_PRUSS_INTC
 config RISCV_INTC
 	bool
 	depends on RISCV
+	select IRQ_DOMAIN_HIERARCHY
 
 config SIFIVE_PLIC
 	bool
diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index 9066467e99e4..784d25645704 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -26,20 +26,7 @@ static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
 	if (unlikely(cause >= BITS_PER_LONG))
 		panic("unexpected interrupt cause");
 
-	switch (cause) {
-#ifdef CONFIG_SMP
-	case RV_IRQ_SOFT:
-		/*
-		 * We only use software interrupts to pass IPIs, so if a
-		 * non-SMP system gets one, then we don't know what to do.
-		 */
-		handle_IPI(regs);
-		break;
-#endif
-	default:
-		generic_handle_domain_irq(intc_domain, cause);
-		break;
-	}
+	generic_handle_domain_irq(intc_domain, cause);
 }
 
 /*
@@ -59,18 +46,6 @@ static void riscv_intc_irq_unmask(struct irq_data *d)
 	csr_set(CSR_IE, BIT(d->hwirq));
 }
 
-static int riscv_intc_cpu_starting(unsigned int cpu)
-{
-	csr_set(CSR_IE, BIT(RV_IRQ_SOFT));
-	return 0;
-}
-
-static int riscv_intc_cpu_dying(unsigned int cpu)
-{
-	csr_clear(CSR_IE, BIT(RV_IRQ_SOFT));
-	return 0;
-}
-
 static struct irq_chip riscv_intc_chip = {
 	.name = "RISC-V INTC",
 	.irq_mask = riscv_intc_irq_mask,
@@ -87,9 +62,32 @@ static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
 	return 0;
 }
 
+static int riscv_intc_domain_alloc(struct irq_domain *domain,
+				   unsigned int virq, unsigned int nr_irqs,
+				   void *arg)
+{
+	int i, ret;
+	irq_hw_number_t hwirq;
+	unsigned int type = IRQ_TYPE_NONE;
+	struct irq_fwspec *fwspec = arg;
+
+	ret = irq_domain_translate_onecell(domain, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = riscv_intc_domain_map(domain, virq + i, hwirq + i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static const struct irq_domain_ops riscv_intc_domain_ops = {
 	.map	= riscv_intc_domain_map,
 	.xlate	= irq_domain_xlate_onecell,
+	.alloc	= riscv_intc_domain_alloc
 };
 
 static struct fwnode_handle *riscv_intc_hwnode(void)
@@ -133,11 +131,6 @@ static int __init riscv_intc_init(struct device_node *node,
 
 	riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
 
-	cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_STARTING,
-			  "irqchip/riscv/intc:starting",
-			  riscv_intc_cpu_starting,
-			  riscv_intc_cpu_dying);
-
 	pr_info("%d local interrupts mapped\n", BITS_PER_LONG);
 
 	return 0;
-- 
2.34.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH v18 4/7] RISC-V: Allow marking IPIs as suitable for remote FENCEs
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
                   ` (2 preceding siblings ...)
  2023-03-28  3:52 ` [PATCH v18 3/7] RISC-V: Treat IPIs as normal Linux IRQs Anup Patel
@ 2023-03-28  3:52 ` Anup Patel
  2023-03-28  3:52 ` [PATCH v18 5/7] RISC-V: Use IPIs for remote TLB flush when possible Anup Patel
                   ` (4 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel, Atish Patra, Palmer Dabbelt

To do remote FENCEs (i.e. remote TLB flushes) using IPI calls on the
RISC-V kernel, we need hardware mechanism to directly inject IPI from
the supervisor mode (i.e. RISC-V kernel) instead of using SBI calls.

The upcoming AIA IMSIC devices allow direct IPI injection from the
supervisor mode (i.e. RISC-V kernel). To support this, we extend the
riscv_ipi_set_virq_range() function so that IPI provider (i.e. irqchip
drivers can mark IPIs as suitable for remote FENCEs.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/include/asm/smp.h      | 18 ++++++++++++++++--
 arch/riscv/kernel/sbi-ipi.c       |  2 +-
 arch/riscv/kernel/smp.c           | 11 ++++++++++-
 drivers/clocksource/timer-clint.c |  2 +-
 4 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 4fe7a8854c2e..c4b77017ec58 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -16,6 +16,9 @@ struct seq_file;
 extern unsigned long boot_cpu_hartid;
 
 #ifdef CONFIG_SMP
+
+#include <linux/jump_label.h>
+
 /*
  * Mapping between linux logical cpu index and hartid.
  */
@@ -46,7 +49,12 @@ void riscv_ipi_disable(void);
 bool riscv_ipi_have_virq_range(void);
 
 /* Set the IPI interrupt numbers for arch (called by irqchip drivers) */
-void riscv_ipi_set_virq_range(int virq, int nr);
+void riscv_ipi_set_virq_range(int virq, int nr, bool use_for_rfence);
+
+/* Check if we can use IPIs for remote FENCEs */
+DECLARE_STATIC_KEY_FALSE(riscv_ipi_for_rfence);
+#define riscv_use_ipi_for_rfence() \
+	static_branch_unlikely(&riscv_ipi_for_rfence)
 
 /* Check other CPUs stop or not */
 bool smp_crash_stop_failed(void);
@@ -96,10 +104,16 @@ static inline bool riscv_ipi_have_virq_range(void)
 	return false;
 }
 
-static inline void riscv_ipi_set_virq_range(int virq, int nr)
+static inline void riscv_ipi_set_virq_range(int virq, int nr,
+					    bool use_for_rfence)
 {
 }
 
+static inline bool riscv_use_ipi_for_rfence(void)
+{
+	return false;
+}
+
 #endif /* CONFIG_SMP */
 
 #if defined(CONFIG_HOTPLUG_CPU) && (CONFIG_SMP)
diff --git a/arch/riscv/kernel/sbi-ipi.c b/arch/riscv/kernel/sbi-ipi.c
index 41981ab88493..a4559695ce62 100644
--- a/arch/riscv/kernel/sbi-ipi.c
+++ b/arch/riscv/kernel/sbi-ipi.c
@@ -72,6 +72,6 @@ void __init sbi_ipi_init(void)
 			  "irqchip/sbi-ipi:starting",
 			  sbi_ipi_starting_cpu, NULL);
 
-	riscv_ipi_set_virq_range(virq, BITS_PER_BYTE);
+	riscv_ipi_set_virq_range(virq, BITS_PER_BYTE, false);
 	pr_info("providing IPIs using SBI IPI extension\n");
 }
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 47e7ecfedb4d..5f985a197eff 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -177,7 +177,10 @@ bool riscv_ipi_have_virq_range(void)
 	return (ipi_virq_base) ? true : false;
 }
 
-void riscv_ipi_set_virq_range(int virq, int nr)
+DEFINE_STATIC_KEY_FALSE(riscv_ipi_for_rfence);
+EXPORT_SYMBOL_GPL(riscv_ipi_for_rfence);
+
+void riscv_ipi_set_virq_range(int virq, int nr, bool use_for_rfence)
 {
 	int i, err;
 
@@ -200,6 +203,12 @@ void riscv_ipi_set_virq_range(int virq, int nr)
 
 	/* Enabled IPIs for boot CPU immediately */
 	riscv_ipi_enable();
+
+	/* Update RFENCE static key */
+	if (use_for_rfence)
+		static_branch_enable(&riscv_ipi_for_rfence);
+	else
+		static_branch_disable(&riscv_ipi_for_rfence);
 }
 
 static const char * const ipi_names[] = {
diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
index 7ccc16dd6a76..9a55e733ae99 100644
--- a/drivers/clocksource/timer-clint.c
+++ b/drivers/clocksource/timer-clint.c
@@ -251,7 +251,7 @@ static int __init clint_timer_init_dt(struct device_node *np)
 	}
 
 	irq_set_chained_handler(clint_ipi_irq, clint_ipi_interrupt);
-	riscv_ipi_set_virq_range(rc, BITS_PER_BYTE);
+	riscv_ipi_set_virq_range(rc, BITS_PER_BYTE, true);
 	clint_clear_ipi();
 #endif
 
-- 
2.34.1


_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH v18 5/7] RISC-V: Use IPIs for remote TLB flush when possible
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
                   ` (3 preceding siblings ...)
  2023-03-28  3:52 ` [PATCH v18 4/7] RISC-V: Allow marking IPIs as suitable for remote FENCEs Anup Patel
@ 2023-03-28  3:52 ` Anup Patel
  2023-03-28  3:52 ` [PATCH v18 6/7] RISC-V: Use IPIs for remote icache " Anup Patel
                   ` (3 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel, Atish Patra, Palmer Dabbelt

If we have specialized interrupt controller (such as AIA IMSIC) which
allows supervisor mode to directly inject IPIs without any assistance
from M-mode or HS-mode then using such specialized interrupt controller,
we can do remote TLB flushes directly from supervisor mode instead of
using the SBI RFENCE calls.

This patch extends remote TLB flush functions to use supervisor mode
IPIs whenever direct supervisor mode IPIs.are supported by interrupt
controller.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/mm/tlbflush.c | 93 +++++++++++++++++++++++++++++++++-------
 1 file changed, 78 insertions(+), 15 deletions(-)

diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index ef701fa83f36..77be59aadc73 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -23,14 +23,62 @@ static inline void local_flush_tlb_page_asid(unsigned long addr,
 			: "memory");
 }
 
+static inline void local_flush_tlb_range(unsigned long start,
+		unsigned long size, unsigned long stride)
+{
+	if (size <= stride)
+		local_flush_tlb_page(start);
+	else
+		local_flush_tlb_all();
+}
+
+static inline void local_flush_tlb_range_asid(unsigned long start,
+		unsigned long size, unsigned long stride, unsigned long asid)
+{
+	if (size <= stride)
+		local_flush_tlb_page_asid(start, asid);
+	else
+		local_flush_tlb_all_asid(asid);
+}
+
+static void __ipi_flush_tlb_all(void *info)
+{
+	local_flush_tlb_all();
+}
+
 void flush_tlb_all(void)
 {
-	sbi_remote_sfence_vma(NULL, 0, -1);
+	if (riscv_use_ipi_for_rfence())
+		on_each_cpu(__ipi_flush_tlb_all, NULL, 1);
+	else
+		sbi_remote_sfence_vma(NULL, 0, -1);
+}
+
+struct flush_tlb_range_data {
+	unsigned long asid;
+	unsigned long start;
+	unsigned long size;
+	unsigned long stride;
+};
+
+static void __ipi_flush_tlb_range_asid(void *info)
+{
+	struct flush_tlb_range_data *d = info;
+
+	local_flush_tlb_range_asid(d->start, d->size, d->stride, d->asid);
+}
+
+static void __ipi_flush_tlb_range(void *info)
+{
+	struct flush_tlb_range_data *d = info;
+
+	local_flush_tlb_range(d->start, d->size, d->stride);
 }
 
-static void __sbi_tlb_flush_range(struct mm_struct *mm, unsigned long start,
-				  unsigned long size, unsigned long stride)
+static void __flush_tlb_range(struct mm_struct *mm, unsigned long start,
+			      unsigned long size, unsigned long stride)
 {
+	struct flush_tlb_range_data ftd;
 	struct cpumask *cmask = mm_cpumask(mm);
 	unsigned int cpuid;
 	bool broadcast;
@@ -45,19 +93,34 @@ static void __sbi_tlb_flush_range(struct mm_struct *mm, unsigned long start,
 		unsigned long asid = atomic_long_read(&mm->context.id) & asid_mask;
 
 		if (broadcast) {
-			sbi_remote_sfence_vma_asid(cmask, start, size, asid);
-		} else if (size <= stride) {
-			local_flush_tlb_page_asid(start, asid);
+			if (riscv_use_ipi_for_rfence()) {
+				ftd.asid = asid;
+				ftd.start = start;
+				ftd.size = size;
+				ftd.stride = stride;
+				on_each_cpu_mask(cmask,
+						 __ipi_flush_tlb_range_asid,
+						 &ftd, 1);
+			} else
+				sbi_remote_sfence_vma_asid(cmask,
+							   start, size, asid);
 		} else {
-			local_flush_tlb_all_asid(asid);
+			local_flush_tlb_range_asid(start, size, stride, asid);
 		}
 	} else {
 		if (broadcast) {
-			sbi_remote_sfence_vma(cmask, start, size);
-		} else if (size <= stride) {
-			local_flush_tlb_page(start);
+			if (riscv_use_ipi_for_rfence()) {
+				ftd.asid = 0;
+				ftd.start = start;
+				ftd.size = size;
+				ftd.stride = stride;
+				on_each_cpu_mask(cmask,
+						 __ipi_flush_tlb_range,
+						 &ftd, 1);
+			} else
+				sbi_remote_sfence_vma(cmask, start, size);
 		} else {
-			local_flush_tlb_all();
+			local_flush_tlb_range(start, size, stride);
 		}
 	}
 
@@ -66,23 +129,23 @@ static void __sbi_tlb_flush_range(struct mm_struct *mm, unsigned long start,
 
 void flush_tlb_mm(struct mm_struct *mm)
 {
-	__sbi_tlb_flush_range(mm, 0, -1, PAGE_SIZE);
+	__flush_tlb_range(mm, 0, -1, PAGE_SIZE);
 }
 
 void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
 {
-	__sbi_tlb_flush_range(vma->vm_mm, addr, PAGE_SIZE, PAGE_SIZE);
+	__flush_tlb_range(vma->vm_mm, addr, PAGE_SIZE, PAGE_SIZE);
 }
 
 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 		     unsigned long end)
 {
-	__sbi_tlb_flush_range(vma->vm_mm, start, end - start, PAGE_SIZE);
+	__flush_tlb_range(vma->vm_mm, start, end - start, PAGE_SIZE);
 }
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
 			unsigned long end)
 {
-	__sbi_tlb_flush_range(vma->vm_mm, start, end - start, PMD_SIZE);
+	__flush_tlb_range(vma->vm_mm, start, end - start, PMD_SIZE);
 }
 #endif
-- 
2.34.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH v18 6/7] RISC-V: Use IPIs for remote icache flush when possible
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
                   ` (4 preceding siblings ...)
  2023-03-28  3:52 ` [PATCH v18 5/7] RISC-V: Use IPIs for remote TLB flush when possible Anup Patel
@ 2023-03-28  3:52 ` Anup Patel
  2023-03-28  3:52 ` [PATCH v18 7/7] irqchip/riscv-intc: Add empty irq_eoi() for chained irq handlers Anup Patel
                   ` (2 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel, Atish Patra, Palmer Dabbelt

If we have specialized interrupt controller (such as AIA IMSIC) which
allows supervisor mode to directly inject IPIs without any assistance
from M-mode or HS-mode then using such specialized interrupt controller,
we can do remote icache flushe directly from supervisor mode instead of
using the SBI RFENCE calls.

This patch extends remote icache flush functions to use supervisor mode
IPIs whenever direct supervisor mode IPIs.are supported by interrupt
controller.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/mm/cacheflush.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index fcd6145fbead..20cec5e7cdbf 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -19,7 +19,7 @@ void flush_icache_all(void)
 {
 	local_flush_icache_all();
 
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
+	if (IS_ENABLED(CONFIG_RISCV_SBI) && !riscv_use_ipi_for_rfence())
 		sbi_remote_fence_i(NULL);
 	else
 		on_each_cpu(ipi_remote_fence_i, NULL, 1);
@@ -67,7 +67,8 @@ void flush_icache_mm(struct mm_struct *mm, bool local)
 		 * with flush_icache_deferred().
 		 */
 		smp_mb();
-	} else if (IS_ENABLED(CONFIG_RISCV_SBI)) {
+	} else if (IS_ENABLED(CONFIG_RISCV_SBI) &&
+		   !riscv_use_ipi_for_rfence()) {
 		sbi_remote_fence_i(&others);
 	} else {
 		on_each_cpu_mask(&others, ipi_remote_fence_i, NULL, 1);
-- 
2.34.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH v18 7/7] irqchip/riscv-intc: Add empty irq_eoi() for chained irq handlers
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
                   ` (5 preceding siblings ...)
  2023-03-28  3:52 ` [PATCH v18 6/7] RISC-V: Use IPIs for remote icache " Anup Patel
@ 2023-03-28  3:52 ` Anup Patel
  2023-03-28  3:56 ` [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
  2023-05-08 14:41 ` patchwork-bot+linux-riscv
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:52 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Thomas Gleixner, Marc Zyngier,
	Daniel Lezcano
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Anup Patel, Palmer Dabbelt

We add empty irq_eoi() in RISC-V INTC driver for child irqchip
drivers (such as PLIC, SBI IPI, CLINT, APLIC, IMSIC, etc) which
implement chained handlers for parent per-HART local interrupts.
This hels us avoid unnecessary mask/unmask of per-HART local
interrupts at the time of handling interrupts.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 drivers/irqchip/irq-riscv-intc.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index 784d25645704..f229e3e66387 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -46,10 +46,27 @@ static void riscv_intc_irq_unmask(struct irq_data *d)
 	csr_set(CSR_IE, BIT(d->hwirq));
 }
 
+static void riscv_intc_irq_eoi(struct irq_data *d)
+{
+	/*
+	 * The RISC-V INTC driver uses handle_percpu_devid_irq() flow
+	 * for the per-HART local interrupts and child irqchip drivers
+	 * (such as PLIC, SBI IPI, CLINT, APLIC, IMSIC, etc) implement
+	 * chained handlers for the per-HART local interrupts.
+	 *
+	 * In the absence of irq_eoi(), the chained_irq_enter() and
+	 * chained_irq_exit() functions (used by child irqchip drivers)
+	 * will do unnecessary mask/unmask of per-HART local interrupts
+	 * at the time of handling interrupts. To avoid this, we provide
+	 * an empty irq_eoi() callback for RISC-V INTC irqchip.
+	 */
+}
+
 static struct irq_chip riscv_intc_chip = {
 	.name = "RISC-V INTC",
 	.irq_mask = riscv_intc_irq_mask,
 	.irq_unmask = riscv_intc_irq_unmask,
+	.irq_eoi = riscv_intc_irq_eoi,
 };
 
 static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
-- 
2.34.1


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^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: [PATCH v18 0/7] RISC-V IPI Improvements
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
                   ` (6 preceding siblings ...)
  2023-03-28  3:52 ` [PATCH v18 7/7] irqchip/riscv-intc: Add empty irq_eoi() for chained irq handlers Anup Patel
@ 2023-03-28  3:56 ` Anup Patel
  2023-05-08 14:41 ` patchwork-bot+linux-riscv
  8 siblings, 0 replies; 10+ messages in thread
From: Anup Patel @ 2023-03-28  3:56 UTC (permalink / raw)
  To: Palmer Dabbelt, Marc Zyngier
  Cc: Atish Patra, Alistair Francis, Anup Patel, linux-riscv,
	linux-kernel, Thomas Gleixner, Paul Walmsley, Daniel Lezcano

Hi Marc and Palmer,

On Tue, Mar 28, 2023 at 9:22 AM Anup Patel <apatel@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_v18 branch at:
> https://github.com/avpatel/linux.git
>
> Changes since v17:
>  - Resolved merge conflicts and rebased on Linux-6.3-rc4
>
> Changes since v16:
>  - Rebased on Linux-6.3-rc1
>  - Dropped PATCH3 and PATCH9 since these patches are already merged
>  - Added Palmer's Acked-by
>
> 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 (7):
>   RISC-V: Clear SIP bit only when using SBI IPI operations
>   irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode
>   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

There were merge conflicts with Linux-6.3-rc4 which are resolved
in this series.

It would be great if this series can be considered for Linux-6.4

Thanks,
Anup

>
>  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           |   1 +
>  drivers/irqchip/irq-riscv-intc.c  |  71 ++++++++-----
>  16 files changed, 429 insertions(+), 248 deletions(-)
>  create mode 100644 arch/riscv/kernel/sbi-ipi.c
>
> --
> 2.34.1
>

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^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH v18 0/7] RISC-V IPI Improvements
  2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
                   ` (7 preceding siblings ...)
  2023-03-28  3:56 ` [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
@ 2023-05-08 14:41 ` patchwork-bot+linux-riscv
  8 siblings, 0 replies; 10+ messages in thread
From: patchwork-bot+linux-riscv @ 2023-05-08 14:41 UTC (permalink / raw)
  To: Anup Patel
  Cc: linux-riscv, palmer, paul.walmsley, tglx, maz, daniel.lezcano,
	atishp, Alistair.Francis, anup, linux-kernel

Hello:

This series was applied to riscv/linux.git (fixes)
by Marc Zyngier <maz@kernel.org>:

On Tue, 28 Mar 2023 09:22:16 +0530 you 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.
> 
> [...]

Here is the summary with links:
  - [v18,1/7] RISC-V: Clear SIP bit only when using SBI IPI operations
    https://git.kernel.org/riscv/c/3ee92565b83e
  - [v18,2/7] irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode
    https://git.kernel.org/riscv/c/0c60a31ce62c
  - [v18,3/7] RISC-V: Treat IPIs as normal Linux IRQs
    https://git.kernel.org/riscv/c/832f15f42646
  - [v18,4/7] RISC-V: Allow marking IPIs as suitable for remote FENCEs
    https://git.kernel.org/riscv/c/fb0f3d281b7f
  - [v18,5/7] RISC-V: Use IPIs for remote TLB flush when possible
    https://git.kernel.org/riscv/c/18d2199d8105
  - [v18,6/7] RISC-V: Use IPIs for remote icache flush when possible
    https://git.kernel.org/riscv/c/627922843235
  - [v18,7/7] irqchip/riscv-intc: Add empty irq_eoi() for chained irq handlers
    https://git.kernel.org/riscv/c/f8415f2def18

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



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^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2023-05-08 14:42 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-03-28  3:52 [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
2023-03-28  3:52 ` [PATCH v18 1/7] RISC-V: Clear SIP bit only when using SBI IPI operations Anup Patel
2023-03-28  3:52 ` [PATCH v18 2/7] irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode Anup Patel
2023-03-28  3:52 ` [PATCH v18 3/7] RISC-V: Treat IPIs as normal Linux IRQs Anup Patel
2023-03-28  3:52 ` [PATCH v18 4/7] RISC-V: Allow marking IPIs as suitable for remote FENCEs Anup Patel
2023-03-28  3:52 ` [PATCH v18 5/7] RISC-V: Use IPIs for remote TLB flush when possible Anup Patel
2023-03-28  3:52 ` [PATCH v18 6/7] RISC-V: Use IPIs for remote icache " Anup Patel
2023-03-28  3:52 ` [PATCH v18 7/7] irqchip/riscv-intc: Add empty irq_eoi() for chained irq handlers Anup Patel
2023-03-28  3:56 ` [PATCH v18 0/7] RISC-V IPI Improvements Anup Patel
2023-05-08 14:41 ` patchwork-bot+linux-riscv

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