For testing only at the moment, firmware does not define these bits.
---
arch/powerpc/include/asm/hvcall.h | 1 +
arch/powerpc/include/uapi/asm/kvm.h | 1 +
arch/powerpc/kvm/powerpc.c | 9 +++++++--
arch/powerpc/platforms/powernv/setup.c | 3 +++
arch/powerpc/platforms/pseries/setup.c | 3 +++
tools/arch/powerpc/include/uapi/asm/kvm.h | 1 +
6 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/hvcall.h
b/arch/powerpc/include/asm/hvcall.h
index e90c073e437e..a92a07c89b6f 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -373,6 +373,7 @@
#define H_CPU_CHAR_THREAD_RECONFIG_CTRL (1ull << 57) // IBM bit 6
#define H_CPU_CHAR_COUNT_CACHE_DISABLED (1ull << 56) // IBM bit 7
#define H_CPU_CHAR_BCCTR_FLUSH_ASSIST (1ull << 54) // IBM bit 9
+#define H_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST (1ull << 53) // IBM bit 10
#define H_CPU_BEHAV_FAVOUR_SECURITY (1ull << 63) // IBM bit 0
#define H_CPU_BEHAV_L1D_FLUSH_PR (1ull << 62) // IBM bit 1
diff --git a/arch/powerpc/include/uapi/asm/kvm.h
b/arch/powerpc/include/uapi/asm/kvm.h
index 264e266a85bf..dd229d5f46ee 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -464,6 +464,7 @@ struct kvm_ppc_cpu_char {
#define KVM_PPC_CPU_CHAR_MTTRIG_THR_RECONF (1ULL << 57)
#define KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS (1ULL << 56)
#define KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST (1ull << 54)
+#define KVM_PPC_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST (1ull << 53)
#define KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY (1ULL << 63)
#define KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR (1ULL << 62)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 27ccff612903..fa981ee09dec 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -2221,7 +2221,8 @@ static int pseries_get_cpu_char(struct kvm_ppc_cpu_char
*cp)
KVM_PPC_CPU_CHAR_BR_HINT_HONOURED |
KVM_PPC_CPU_CHAR_MTTRIG_THR_RECONF |
KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS |
- KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST;
+ KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST |
+ KVM_PPC_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST;
cp->behaviour_mask = KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY |
KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR |
KVM_PPC_CPU_BEHAV_BNDS_CHK_SPEC_BAR |
@@ -2287,13 +2288,17 @@ static int kvmppc_get_cpu_char(struct kvm_ppc_cpu_char
*cp)
if (have_fw_feat(fw_features, "enabled",
"fw-count-cache-flush-bcctr2,0,0"))
cp->character |= KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST;
+ if (have_fw_feat(fw_features, "enabled",
+ "fw-link-stack-flush-bcctr2,0,0"))
+ cp->character |=
KVM_PPC_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST;
cp->character_mask = KVM_PPC_CPU_CHAR_SPEC_BAR_ORI31 |
KVM_PPC_CPU_CHAR_BCCTRL_SERIALISED |
KVM_PPC_CPU_CHAR_L1D_FLUSH_ORI30 |
KVM_PPC_CPU_CHAR_L1D_FLUSH_TRIG2 |
KVM_PPC_CPU_CHAR_L1D_THREAD_PRIV |
KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS |
- KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST;
+ KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST |
+ KVM_PPC_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST;
if (have_fw_feat(fw_features, "enabled",
"speculation-policy-favor-security"))
diff --git a/arch/powerpc/platforms/powernv/setup.c
b/arch/powerpc/platforms/powernv/setup.c
index 3bc188da82ba..1a06d3b4c0a9 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -78,6 +78,9 @@ static void init_fw_feat_flags(struct device_node *np)
if (fw_feature_is("enabled", "fw-count-cache-flush-bcctr2,0,0", np))
security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);
+ if (fw_feature_is("enabled", "fw-link-stack-flush-bcctr2,0,0", np))
+ security_ftr_set(SEC_FTR_BCCTR_LINK_FLUSH_ASSIST);
+
if (fw_feature_is("enabled",
"needs-count-cache-flush-on-context-switch", np))
security_ftr_set(SEC_FTR_FLUSH_COUNT_CACHE);
diff --git a/arch/powerpc/platforms/pseries/setup.c
b/arch/powerpc/platforms/pseries/setup.c
index 64d18f4bf093..70c9264f23c5 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -517,6 +517,9 @@ static void init_cpu_char_feature_flags(struct
h_cpu_char_result *result)
if (result->character & H_CPU_CHAR_BCCTR_FLUSH_ASSIST)
security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);
+ if (result->character & H_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST)
+ security_ftr_set(SEC_FTR_BCCTR_LINK_FLUSH_ASSIST);
+
if (result->behaviour & H_CPU_BEHAV_FLUSH_COUNT_CACHE)
security_ftr_set(SEC_FTR_FLUSH_COUNT_CACHE);
diff --git a/tools/arch/powerpc/include/uapi/asm/kvm.h
b/tools/arch/powerpc/include/uapi/asm/kvm.h
index 264e266a85bf..dd229d5f46ee 100644
--- a/tools/arch/powerpc/include/uapi/asm/kvm.h
+++ b/tools/arch/powerpc/include/uapi/asm/kvm.h
@@ -464,6 +464,7 @@ struct kvm_ppc_cpu_char {
#define KVM_PPC_CPU_CHAR_MTTRIG_THR_RECONF (1ULL << 57)
#define KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS (1ULL << 56)
#define KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST (1ull << 54)
+#define KVM_PPC_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST (1ull << 53)
#define KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY (1ULL << 63)
#define KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR (1ULL << 62)
--
2.23.0
