The mechanism to trigger IPI is generally part of interrupt-controller
driver for various architectures. On RISC-V, we have an option to trigger
IPI using SBI or SOC vendor can implement RISC-V CPU where IPI will be
triggered using SOC interrupt-controller (e.g. custom PLIC).
This patch makes IPI triggering flexible by providing a mechanism for
interrupt-controller driver to register IPI trigger function using
set_smp_ipi_trigger() function.
Signed-off-by: Anup Patel <a...@brainfault.org>
---
arch/riscv/include/asm/irq.h | 1 -
arch/riscv/include/asm/smp.h | 10 ++++++++++
arch/riscv/kernel/irq.c | 26 +++++++++++++++++++++-----
arch/riscv/kernel/smp.c | 23 +++++++++++++++++++----
4 files changed, 50 insertions(+), 10 deletions(-)
diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index 996b6fbe17a6..93eb75eac4ff 100644
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -18,7 +18,6 @@
#define NR_IRQS 0
void riscv_timer_interrupt(void);
-void riscv_software_interrupt(void);
#include <asm-generic/irq.h>
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 36016845461d..72671580e1d4 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -27,6 +27,16 @@
/* 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);
+
+/*
+ * Provide a function to raise an IPI on CPUs in callmap.
+ */
+void __init set_smp_ipi_trigger(void (*fn)(const struct cpumask *));
+
/* Hook for the generic smp_call_function_many() routine. */
void arch_send_call_function_ipi_mask(struct cpumask *mask);
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 0cfac48a1272..5532e7cedaec 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -9,6 +9,8 @@
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
+#include <asm/sbi.h>
+
/*
* Possible interrupt causes:
*/
@@ -26,12 +28,15 @@
asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause)
{
- struct pt_regs *old_regs = set_irq_regs(regs);
+ struct pt_regs *old_regs;
- irq_enter();
switch (cause & ~INTERRUPT_CAUSE_FLAG) {
case INTERRUPT_CAUSE_TIMER:
+ old_regs = set_irq_regs(regs);
+ irq_enter();
riscv_timer_interrupt();
+ irq_exit();
+ set_irq_regs(old_regs);
break;
#ifdef CONFIG_SMP
case INTERRUPT_CAUSE_SOFTWARE:
@@ -39,21 +44,32 @@ asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs,
unsigned long cause)
* We only use software interrupts to pass IPIs, so if a non-SMP
* system gets one, then we don't know what to do.
*/
- riscv_software_interrupt();
+ handle_IPI(regs);
break;
#endif
case INTERRUPT_CAUSE_EXTERNAL:
+ old_regs = set_irq_regs(regs);
+ irq_enter();
handle_arch_irq(regs);
+ irq_exit();
+ set_irq_regs(old_regs);
break;
default:
panic("unexpected interrupt cause");
}
- irq_exit();
+}
- set_irq_regs(old_regs);
+#ifdef CONFIG_SMP
+static void smp_ipi_trigger_sbi(const struct cpumask *to_whom)
+{
+ sbi_send_ipi(cpumask_bits(to_whom));
}
+#endif
void __init init_IRQ(void)
{
irqchip_init();
+#ifdef CONFIG_SMP
+ set_smp_ipi_trigger(smp_ipi_trigger_sbi);
+#endif
}
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 906fe21ea21b..04571d77eceb 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -38,17 +38,19 @@ enum ipi_message_type {
IPI_MAX
};
-
/* Unsupported */
int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
-void riscv_software_interrupt(void)
+void handle_IPI(struct pt_regs *regs)
{
+ struct pt_regs *old_regs = set_irq_regs(regs);
unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
+ irq_enter();
+
/* Clear pending IPI */
csr_clear(sip, SIE_SSIE);
@@ -60,7 +62,7 @@ void riscv_software_interrupt(void)
ops = xchg(pending_ipis, 0);
if (ops == 0)
- return;
+ goto done;
if (ops & (1 << IPI_RESCHEDULE))
scheduler_ipi();
@@ -73,6 +75,17 @@ void riscv_software_interrupt(void)
/* Order data access and bit testing. */
mb();
}
+
+done:
+ irq_exit();
+ set_irq_regs(old_regs);
+}
+
+static void (*__smp_ipi_trigger)(const struct cpumask *);
+
+void __init set_smp_ipi_trigger(void (*fn)(const struct cpumask *))
+{
+ __smp_ipi_trigger = fn;
}
static void
@@ -85,7 +98,9 @@ send_ipi_message(const struct cpumask *to_whom, enum
ipi_message_type operation)
set_bit(operation, &ipi_data[i].bits);
mb();
- sbi_send_ipi(cpumask_bits(to_whom));
+
+ if (__smp_ipi_trigger)
+ __smp_ipi_trigger(to_whom);
}
void arch_send_call_function_ipi_mask(struct cpumask *mask)
--
2.17.1
