sparc64: Run NMIs on the hardirq stack.

Otherwise we can overflow the main stack with the function tracer
enabled.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/sparc/kernel/nmi.c b/arch/sparc/kernel/nmi.c
index 75a3d1a25356..a4bd7ba74c89 100644
--- a/arch/sparc/kernel/nmi.c
+++ b/arch/sparc/kernel/nmi.c
@@ -23,6 +23,8 @@
 #include <asm/ptrace.h>
 #include <asm/pcr.h>
 
+#include "kstack.h"
+
 /* We don't have a real NMI on sparc64, but we can fake one
  * up using profiling counter overflow interrupts and interrupt
  * levels.
@@ -92,6 +94,7 @@ static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
 notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
 {
 	unsigned int sum, touched = 0;
+	void *orig_sp;
 
 	clear_softint(1 << irq);
 
@@ -99,6 +102,8 @@ notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
 
 	nmi_enter();
 
+	orig_sp = set_hardirq_stack();
+
 	if (notify_die(DIE_NMI, "nmi", regs, 0,
 		       pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
 		touched = 1;
@@ -124,6 +129,8 @@ notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
 		pcr_ops->write(pcr_enable);
 	}
 
+	restore_hardirq_stack(orig_sp);
+
 	nmi_exit();
 }