[PATCH stable v4.14 16/32] powerpc/64s: Add new security feature flags for count cache flush

Michael Ellerman mpe at ellerman.id.au
Fri Mar 29 22:26:04 AEDT 2019

commit dc8c6cce9a26a51fc19961accb978217a3ba8c75 upstream.

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 at ellerman.id.au>
 arch/powerpc/include/asm/security_features.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h
index 44989b22383c..a0d47bc18a5c 100644
--- a/arch/powerpc/include/asm/security_features.h
+++ b/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 \

More information about the Linuxppc-dev mailing list