guoren@xxxxxxxxxx writes:
> 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.
>
> Tested-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
> Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
> ---
> arch/riscv/Kconfig | 7 ++++---
> arch/riscv/kernel/irq.c | 33 +++++++++++++++++++++++++++++++++
> 2 files changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 0a9d4bdc0338..bd4c4ae4cdc9 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -447,12 +447,13 @@ 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
HAVE_IRQ_EXIT_ON_IRQ_STACK is used by softirq.c Shouldn't that be
selected introduced in this patch, instead of the previous one?
> 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.
Same comment from previous patch. Please use the same wording/config as
other archs.
> endmenu # "Platform type"
>
> diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
> index 5d77f692b198..a6406da34937 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 +39,38 @@ static void init_irq_stacks(void)
> per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
> }
> #endif /* CONFIG_VMAP_STACK */
> +
> +#ifdef CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK
> +void do_softirq_own_stack(void)
> +{
> +#ifdef CONFIG_IRQ_STACKS
> + if (on_thread_stack()) {
> + ulong *sp = per_cpu(irq_stack_ptr, smp_processor_id())
> + + IRQ_STACK_SIZE/sizeof(ulong);
> + __asm__ __volatile(
> + "addi sp, sp, -"RISCV_SZPTR "\n"
> + REG_S" ra, (sp) \n"
> + "addi sp, sp, -"RISCV_SZPTR "\n"
> + REG_S" s0, (sp) \n"
> + "addi s0, sp, 2*"RISCV_SZPTR "\n"
> + "move sp, %[sp] \n"
> + "call __do_softirq \n"
> + "addi sp, s0, -2*"RISCV_SZPTR"\n"
> + REG_L" s0, (sp) \n"
> + "addi sp, sp, "RISCV_SZPTR "\n"
> + REG_L" ra, (sp) \n"
> + "addi sp, sp, "RISCV_SZPTR "\n"
> + :
> + : [sp] "r" (sp)
> + : "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7",
> + "t0", "t1", "t2", "t3", "t4", "t5", "t6",
> + "memory");
Same as previous patch. Please avoid C&P and have a look at how
call_on_stack is done on x86.
Björn
