powerpc/64s: Add new security feature flags for count cache flush

Add security feature flags to indicate the need for software to flush
the count cache on context switch, and for the presence of a hardware
assisted count cache flush.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/security_features.h

@@ -59,6 +59,9 @@ static inline bool security_ftr_enabled(unsigned long feature)
 // Indirect branch prediction cache disabled
 #define SEC_FTR_COUNT_CACHE_DISABLED	0x0000000000000020ull
 
+// bcctr 2,0,0 triggers a hardware assisted count cache flush
+#define SEC_FTR_BCCTR_FLUSH_ASSIST	0x0000000000000800ull
+
 
 // Features indicating need for Spectre/Meltdown mitigations
 
@@ -74,6 +77,9 @@ static inline bool security_ftr_enabled(unsigned long feature)
 // Firmware configuration indicates user favours security over performance
 #define SEC_FTR_FAVOUR_SECURITY		0x0000000000000200ull
 
+// Software required to flush count cache on context switch
+#define SEC_FTR_FLUSH_COUNT_CACHE	0x0000000000000400ull
+
 
 // Features enabled by default
 #define SEC_FTR_DEFAULT \