Unverified Commit dd69d07a authored by Guo Ren's avatar Guo Ren Committed by Palmer Dabbelt
Browse files

riscv: stack: Support HAVE_SOFTIRQ_ON_OWN_STACK 



Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config, and
the irq and softirq use the same irq_stack of percpu.

Tested-by: default avatarJisheng Zhang <jszhang@kernel.org>
Signed-off-by: default avatarGuo Ren <guoren@linux.alibaba.com>
Signed-off-by: default avatarGuo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20230614013018.2168426-3-guoren@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 163e76cc

arch/riscv/Kconfig

+4 −2
Original line number Diff line number Diff line
@@ -591,11 +591,13 @@ 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.

	  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"

arch/riscv/kernel/irq.c

+35 −0
Original line number Diff line number Diff line
@@ -11,6 +11,9 @@ 
#include <linux/module.h>

#include <linux/seq_file.h>

#include <asm/sbi.h>

#include <asm/smp.h>

#include <asm/softirq_stack.h>

#include <asm/stacktrace.h>



static struct fwnode_handle *(*__get_intc_node)(void);
@@ -56,6 +59,38 @@ 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");

	} else

#endif

		__do_softirq();

}

#endif /* CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK */



#else

static void init_irq_stacks(void) {}

#endif /* CONFIG_IRQ_STACKS */