parisc64: Add .opd based function descriptor dereference

We are moving towards separate kernel and module function descriptor
dereference callbacks. This patch enables it for parisc64.

For pointers that belong to the kernel
-  Added __start_opd and __end_opd pointers, to track the kernel
   .opd section address range;

-  Added dereference_kernel_function_descriptor(). Now we
   will dereference only function pointers that are within
   [__start_opd, __end_opd);

For pointers that belong to a module
-  Added dereference_module_function_descriptor() to handle module
   function descriptor dereference. Now we will dereference only
   pointers that are within [module->opd.start, module->opd.end).

Link: http://lkml.kernel.org/r/[email protected]
To: Tony Luck <[email protected]>
To: Fenghua Yu <[email protected]>
To: Helge Deller <[email protected]>
To: Benjamin Herrenschmidt <[email protected]>
To: Paul Mackerras <[email protected]>
To: Michael Ellerman <[email protected]>
To: James Bottomley <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Tested-by: Helge Deller <[email protected]> #parisc64
Signed-off-by: Petr Mladek <[email protected]>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 30f92391a93e..6c4585103a91 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -276,6 +276,15 @@ void *dereference_function_descriptor(void *ptr)
 		ptr = p;
 	return ptr;
 }
+
+void *dereference_kernel_function_descriptor(void *ptr)
+{
+	if (ptr < (void *)__start_opd ||
+			ptr >= (void *)__end_opd)
+		return ptr;
+
+	return dereference_function_descriptor(ptr);
+}
 #endif
 
 static inline unsigned long brk_rnd(void)