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authorAndi Kleen <ak@suse.de>2005-07-28 21:15:49 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-07-28 21:46:02 -0700
commited6b676ca8b50e0b538e61c283d52fd04f007abf (patch)
tree753ea613ce334c41f835f6aac21074b137d24713 /arch
parent3829ee6b1be03d5aa3005fe7d19f30088b539836 (diff)
[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 <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86_64/kernel/entry.S12
-rw-r--r--arch/x86_64/kernel/irq.c19
2 files changed, 31 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index 0696e025dce..096d470e280 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 cc3fb85f514..849a20aec7c 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);