Commit 6ea312d9 authored by Juergen Gross's avatar Juergen Gross Committed by Borislav Petkov
Browse files

static_call: Add function to query current function 



Some users of paravirtualized functions need to query which function
has been specified in a pv_ops vector element. In order to be able to
switch such paravirtualized functions to static_calls instead, there
needs to be a function to query the function which will be called via
static_call().

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210311142319.4723-4-jgross@suse.com
parent b0466648

include/linux/static_call.h

+8 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
 *   static_call(name)(args...);

 *   static_call_cond(name)(args...);

 *   static_call_update(name, func);

 *   static_call_query(name);

 *

 * Usage example:

 *
@@ -91,6 +92,10 @@ 
 *

 *   which will include the required value tests to avoid NULL-pointer

 *   dereferences.

 *

 *   To query which function is currently set to be called, use:

 *

 *   func = static_call_query(name);

 */



#include <linux/types.h>
@@ -118,6 +123,8 @@ extern void arch_static_call_transform(void *site, void *tramp, void *func, bool 
			     STATIC_CALL_TRAMP_ADDR(name), func);	\

})



#define static_call_query(name) (READ_ONCE(STATIC_CALL_KEY(name).func))



#ifdef CONFIG_HAVE_STATIC_CALL_INLINE



extern int __init static_call_init(void);
@@ -191,6 +198,7 @@ static inline int static_call_init(void) { return 0; } 
	};								\

	ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)





#define static_call_cond(name)	(void)__static_call(name)



static inline