From ed6b676ca8b50e0b538e61c283d52fd04f007abf Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 28 Jul 2005 21:15:49 -0700 Subject: [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 +++++++++++++++++++ 2 files changed, 31 insertions(+) (limited to 'arch/x86_64') 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); -- cgit v1.2.2