diff mbox series

[V4,7/8] riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK

Message ID 20220908022506.1275799-8-guoren@kernel.org (mailing list archive)
State New, archived
Headers show
Series riscv: Add GENERIC_ENTRY, irq stack support | expand

Commit Message

Guo Ren Sept. 8, 2022, 2:25 a.m. UTC 
From: Guo Ren <guoren@linux.alibaba.com>

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@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
 arch/riscv/Kconfig      |  7 ++++---
 arch/riscv/kernel/irq.c | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

Comments

Sebastian Sewior Sept. 8, 2022, 4:01 p.m. UTC | #1 
On 2022-09-07 22:25:05 [-0400], guoren@kernel.org wrote:
> --- 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 */
> +
> +#ifndef CONFIG_PREEMPT_RT

Could you please replace it with 
	#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK

instead? See
	https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git/commit/?id=8cbb2b50ee2dcb082675237eaaa48fe8479f8aa5

> +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_PREEMPT_RT */
> +
>  #else
>  static void init_irq_stacks(void) {}
>  #endif /* CONFIG_IRQ_STACKS */

Sebastian
Guo Ren Sept. 18, 2022, 3:42 p.m. UTC | #2 
On Fri, Sep 9, 2022 at 12:01 AM Sebastian Andrzej Siewior
<bigeasy@linutronix.de> wrote:
>
> On 2022-09-07 22:25:05 [-0400], guoren@kernel.org wrote:
> > --- 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 */
> > +
> > +#ifndef CONFIG_PREEMPT_RT
>
> Could you please replace it with
>         #ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
Thx, I would.

>
> instead? See
>         https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git/commit/?id=8cbb2b50ee2dcb082675237eaaa48fe8479f8aa5
>
> > +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_PREEMPT_RT */
> > +
> >  #else
> >  static void init_irq_stacks(void) {}
> >  #endif /* CONFIG_IRQ_STACKS */
>
> Sebastian
diff mbox series

Patch

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index a8a12b4ba1a9..da548ed7d107 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"
+	bool "Independent irq & softirq stacks"
 	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..c09cd4d28308 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 */
+
+#ifndef CONFIG_PREEMPT_RT
+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_PREEMPT_RT */
+
 #else
 static void init_irq_stacks(void) {}
 #endif /* CONFIG_IRQ_STACKS */