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Message-Id: <20221208025816.138712-10-guoren@kernel.org>
Date: Wed, 7 Dec 2022 21:58:15 -0500
From: guoren@...nel.org
To: arnd@...db.de, guoren@...nel.org, palmer@...osinc.com,
tglx@...utronix.de, peterz@...radead.org, luto@...nel.org,
conor.dooley@...rochip.com, heiko@...ech.de, jszhang@...nel.org,
lazyparser@...il.com, falcon@...ylab.org, chenhuacai@...nel.org,
apatel@...tanamicro.com, atishp@...shpatra.org, palmer@...belt.com,
paul.walmsley@...ive.com, mark.rutland@....com,
zouyipeng@...wei.com, bigeasy@...utronix.de,
David.Laight@...lab.com, chenzhongjin@...wei.com,
greentime.hu@...ive.com, andy.chiu@...ive.com, ben@...adent.org.uk,
bjorn@...nel.org
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-riscv@...ts.infradead.org, Guo Ren <guoren@...ux.alibaba.com>
Subject: [PATCH -next V10 09/10] riscv: stack: Support HAVE_SOFTIRQ_ON_OWN_STACK
From: Guo Ren <guoren@...ux.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.
Tested-by: Jisheng Zhang <jszhang@...nel.org>
Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
Signed-off-by: Guo Ren <guoren@...nel.org>
---
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
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 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");
+ } else
+#endif
+ __do_softirq();
+}
+#endif /* CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK */
+
#else
static void init_irq_stacks(void) {}
#endif /* CONFIG_IRQ_STACKS */
--
2.36.1
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