From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config. The
irq and softirq use the same independent irq_stack of percpu by time
division multiplexing.
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
arch/riscv/Kconfig | 7 ++++---
arch/riscv/kernel/irq.c | 16 ++++++++++++++++
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 75db47a983f2..dfe600f3526c 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -434,12 +434,13 @@ config FPU
If you don't know what to do here, say Y.
config IRQ_STACKS
- bool "Independent irq stacks" if EXPERT
+ bool "Independent irq & softirq stacks" if EXPERT
default y
select HAVE_IRQ_EXIT_ON_IRQ_STACK
+ select HAVE_SOFTIRQ_ON_OWN_STACK
help
- Add independent irq stacks for percpu to prevent kernel stack overflows.
- We may save some memory footprint by disabling IRQ_STACKS.
+ Add independent irq & softirq stacks for percpu to prevent kernel stack
+ overflows. We may save some memory footprint by disabling IRQ_STACKS.
endmenu # "Platform type"
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 5ad4952203c5..6dc9ccd01470 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -11,6 +11,7 @@
#include <linux/seq_file.h>
#include <asm/smp.h>
#include <asm/vmap_stack.h>
+#include <asm/softirq_stack.h>
#ifdef CONFIG_IRQ_STACKS
static DEFINE_PER_CPU(ulong *, irq_stack_ptr);
@@ -38,6 +39,21 @@ static void init_irq_stacks(void)
per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
}
#endif /* CONFIG_VMAP_STACK */
+
+#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
+static void do_riscv_softirq(struct pt_regs *regs)
+{
+ __do_softirq();
+}
+
+void do_softirq_own_stack(void)
+{
+ ulong *sp = per_cpu(irq_stack_ptr, smp_processor_id());
+
+ call_on_stack(NULL, sp, do_riscv_softirq, 0);
+}
+#endif /* CONFIG_SOFTIRQ_ON_OWN_STACK */
+
#else
static void init_irq_stacks(void) {}
#endif /* CONFIG_IRQ_STACKS */
--
2.36.1
