[POWERPC] Export virq mapping via debugfs

This adds a debugfs file "powerpc/virq_mapping", which shows the virtual
to real mapping of irq numbers.  Enable it with CONFIG_VIRQ_DEBUG.

Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
Signed-off-by: Chen Gong <G.Chen@freescale.com>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 22acece95b11..c38bc2237057 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -124,6 +124,16 @@ config IRQSTACKS
           for handling hard and soft interrupts.  This can help avoid
           overflowing the process kernel stacks.
 
+config VIRQ_DEBUG
+        bool "Expose hardware/virtual IRQ mapping via debugfs"
+        depends on DEBUG_FS && PPC_MERGE
+        help
+          This option will show the mapping relationship between hardware irq
+          numbers and virtual irq numbers. The mapping is exposed via debugfs
+          in the file powerpc/virq_mapping.
+
+          If you don't know what this means you don't need it.
+
 config BDI_SWITCH
         bool "Include BDI-2000 user context switcher"
         depends on DEBUG_KERNEL && PPC32