[PATCH 20/23] x86, kaiser: add a function to check for KAISER being enabled

Dave Hansen
2017-11-23T00:37:29Z

From: Dave Hansen <dave.hansen@linux.intel.com>

Currently, all of the checks for KAISER are compile-time checks.

Runtime checks are needed for turning it on/off at runtime.

Add a function to do that.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Moritz Lipp <moritz.lipp@iaik.tugraz.at>
Cc: Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Cc: Michael Schwarz <michael.schwarz@iaik.tugraz.at>
Cc: Richard Fellner <richard.fellner@student.tugraz.at>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: x86@kernel.org
---

b/arch/x86/include/asm/kaiser.h | 5 +++++
b/include/linux/kaiser.h | 5 +++++
2 files changed, 10 insertions(+)

diff -puN arch/x86/include/asm/kaiser.h~kaiser-dynamic-check-func arch/x86/include/asm/kaiser.h
--- a/arch/x86/include/asm/kaiser.h~kaiser-dynamic-check-func 2017-11-22 15:45:55.262619723 -0800
+++ b/arch/x86/include/asm/kaiser.h 2017-11-22 15:45:55.267619723 -0800
@@ -56,6 +56,11 @@ extern void kaiser_remove_mapping(unsign
*/
extern void kaiser_init(void);

+static inline bool kaiser_active(void)
+{
+ extern int kaiser_enabled;
+ return kaiser_enabled;
+}
#endif

#endif /* __ASSEMBLY__ */
diff -puN include/linux/kaiser.h~kaiser-dynamic-check-func include/linux/kaiser.h
--- a/include/linux/kaiser.h~kaiser-dynamic-check-func 2017-11-22 15:45:55.264619723 -0800
+++ b/include/linux/kaiser.h 2017-11-22 15:45:55.268619723 -0800
@@ -28,5 +28,10 @@ static inline int kaiser_add_mapping(uns
static inline void kaiser_add_mapping_cpu_entry(int cpu)
{
}
+
+static inline bool kaiser_active(void)
+{
+ return 0;
+}
#endif /* !CONFIG_KAISER */
#endif /* _INCLUDE_KAISER_H */
_