MIPS: Provide a symbol for the legacy performance counter interrupt.

Based on https://patchwork.linux-mips.org/patch/3576 - but this really
deserves its own patchset and the symbol should also be used :)

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 2 insertions, 1 deletions

diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h
index fb698dc09bc9..78dbb8a86da2 100644
--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -136,6 +136,7 @@ extern void free_irqno(unsigned int irq);
  * IE7.  Since R2 their number has to be read from the c0_intctl register.
  */
 #define CP0_LEGACY_COMPARE_IRQ 7
+#define CP0_LEGACY_PERFCNT_IRQ 7
 
 extern int cp0_compare_irq;
 extern int cp0_compare_irq_shift;
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 2d0c2a277f52..f985b7292cd9 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1597,7 +1597,7 @@ void __cpuinit per_cpu_trap_init(bool is_boot_cpu)
                         cp0_perfcount_irq = -1;
         } else {
                 cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
-                cp0_compare_irq_shift = cp0_compare_irq;
+                cp0_compare_irq_shift = CP0_LEGACY_PERFCNT_IRQ;
                 cp0_perfcount_irq = -1;
         }