From ed6b676ca8b50e0b538e61c283d52fd04f007abf Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 28 Jul 2005 21:15:49 -0700 Subject: [PATCH] [PATCH] x86_64: Switch to the interrupt stack when running a softirq in local_bh_enable() This avoids some potential stack overflows with very deep softirq callchains. i386 does this too. TOADD CFI annotation Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/entry.S | 12 ++++++++++++ arch/x86_64/kernel/irq.c | 19 +++++++++++++++++++ include/asm-x86_64/irq.h | 2 ++ kernel/softirq.c | 4 ++-- 4 files changed, 35 insertions(+), 2 deletions(-) diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S index 0696e025dce5..096d470e280f 100644 --- a/arch/x86_64/kernel/entry.S +++ b/arch/x86_64/kernel/entry.S @@ -918,3 +918,15 @@ ENTRY(machine_check) ENTRY(call_debug) zeroentry do_call_debug +ENTRY(call_softirq) + movq %gs:pda_irqstackptr,%rax + pushq %r15 + movq %rsp,%r15 + incl %gs:pda_irqcount + cmove %rax,%rsp + call __do_softirq + movq %r15,%rsp + decl %gs:pda_irqcount + popq %r15 + ret + diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c index cc3fb85f5145..849a20aec7ca 100644 --- a/arch/x86_64/kernel/irq.c +++ b/arch/x86_64/kernel/irq.c @@ -135,3 +135,22 @@ void fixup_irqs(cpumask_t map) local_irq_disable(); } #endif + +extern void call_softirq(void); + +asmlinkage void do_softirq(void) +{ + __u32 pending; + unsigned long flags; + + if (in_interrupt()) + return; + + local_irq_save(flags); + pending = local_softirq_pending(); + /* Switch to interrupt stack */ + if (pending) + call_softirq(); + local_irq_restore(flags); +} +EXPORT_SYMBOL(do_softirq); diff --git a/include/asm-x86_64/irq.h b/include/asm-x86_64/irq.h index eb3b7aa9eb9f..4482657777bb 100644 --- a/include/asm-x86_64/irq.h +++ b/include/asm-x86_64/irq.h @@ -57,4 +57,6 @@ int handle_IRQ_event(unsigned int, struct pt_regs *, struct irqaction *); extern void fixup_irqs(cpumask_t map); #endif +#define __ARCH_HAS_DO_SOFTIRQ 1 + #endif /* _ASM_IRQ_H */ diff --git a/kernel/softirq.c b/kernel/softirq.c index b4ab6af1dea8..31007d6542cc 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -86,7 +86,7 @@ asmlinkage void __do_softirq(void) /* Reset the pending bitmask before enabling irqs */ local_softirq_pending() = 0; - local_irq_enable(); + //local_irq_enable(); h = softirq_vec; @@ -99,7 +99,7 @@ asmlinkage void __do_softirq(void) pending >>= 1; } while (pending); - local_irq_disable(); + //local_irq_disable(); pending = local_softirq_pending(); if (pending && --max_restart)