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>

3 files changed, 27 insertions, 18 deletions

diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index 2b04c722cc3e..830d70a3e20b 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -47,6 +47,7 @@
 
 #include "entry.h"
 #include "cpumap.h"
+#include "kstack.h"
 
 #define NUM_IVECS       (IMAP_INR + 1)
 
@@ -713,24 +714,6 @@ void ack_bad_irq(unsigned int virt_irq)
 void *hardirq_stack[NR_CPUS];
 void *softirq_stack[NR_CPUS];
 
-static __attribute__((always_inline)) void *set_hardirq_stack(void)
-{
-        void *orig_sp, *sp = hardirq_stack[smp_processor_id()];
-
-        __asm__ __volatile__("mov %%sp, %0" : "=r" (orig_sp));
-        if (orig_sp < sp ||
-            orig_sp > (sp + THREAD_SIZE)) {
-                sp += THREAD_SIZE - 192 - STACK_BIAS;
-                __asm__ __volatile__("mov %0, %%sp" : : "r" (sp));
-        }
-
-        return orig_sp;
-}
-static __attribute__((always_inline)) void restore_hardirq_stack(void *orig_sp)
-{
-        __asm__ __volatile__("mov %0, %%sp" : : "r" (orig_sp));
-}
-
 void __irq_entry handler_irq(int irq, struct pt_regs *regs)
 {
         unsigned long pstate, bucket_pa;
diff --git a/arch/sparc/kernel/kstack.h b/arch/sparc/kernel/kstack.h
index 5247283d1c03..53dfb92e09fb 100644
--- a/arch/sparc/kernel/kstack.h
+++ b/arch/sparc/kernel/kstack.h
@@ -61,4 +61,23 @@ check_magic:
 
 }
 
+static inline __attribute__((always_inline)) void *set_hardirq_stack(void)
+{
+        void *orig_sp, *sp = hardirq_stack[smp_processor_id()];
+
+        __asm__ __volatile__("mov %%sp, %0" : "=r" (orig_sp));
+        if (orig_sp < sp ||
+            orig_sp > (sp + THREAD_SIZE)) {
+                sp += THREAD_SIZE - 192 - STACK_BIAS;
+                __asm__ __volatile__("mov %0, %%sp" : : "r" (sp));
+        }
+
+        return orig_sp;
+}
+
+static inline __attribute__((always_inline)) void restore_hardirq_stack(void *orig_sp)
+{
+        __asm__ __volatile__("mov %0, %%sp" : : "r" (orig_sp));
+}
+
 #endif /* _KSTACK_H */
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();
 }