Subject: [PATCH 1/4] powerpc/book3s64/mm: Don't do tlbie fixup for some hardware revisions

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Tue, 24 Sep 2019 09:22:51 +0530

The store ordering vs tlbie issue mentioned in
commit a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on
POWER9") is fixed for Nimbus 2.3 and Cumulus 1.3 revisions. We don't need
to apply the fixup if we are running on them

We can only do this on PowerNV. On pseries guest with kvm we still don't
support redoing the feature fixup after migration. So we should be enabling
all the workarounds needed, because whe can possibly migrate between
DD 2.3 and DD 2.2

Signed-off-by: Aneesh Kumar K.V <[email-masked]>
---
 arch/powerpc/kernel/dt_cpu_ftrs.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index bd95318d2202..eeaff2085120 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -691,9 +691,35 @@ static bool __init cpufeatures_process_feature(struct dt_cpu_feature *f)
 	return true;
 }
 
+/*
+ * Handle POWER9 broadcast tlbie invalidation issue using
+ * cpu feature flag.
+ */
+static __init void update_tlbie_feature_flag(unsigned long pvr)
+{
+	if (PVR_VER(pvr) == PVR_POWER9) {
+		/*
+		 * Set the tlbie feature flag for anything below
+		 * Nimbus DD 2.3 and Cumulus DD 1.3
+		 */
+		if ((pvr & 0xe000) == 0) {
+			/* Nimbus */
+			if ((pvr & 0xfff) < 0x203)
+				cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+		} else if ((pvr & 0xc000) == 0) {
+			/* Cumulus */
+			if ((pvr & 0xfff) < 0x103)
+				cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+		} else {
+			WARN_ONCE(1, "Unknown PVR");
+			cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
+		}
+	}
+}
+
 static __init void cpufeatures_cpu_quirks(void)
 {
-	int version = mfspr(SPRN_PVR);
+	unsigned long version = mfspr(SPRN_PVR);
 
 	/*
 	 * Not all quirks can be derived from the cpufeatures device tree.
@@ -712,10 +738,10 @@ static __init void cpufeatures_cpu_quirks(void)
 
 	if ((version & 0xffff0000) == 0x004e0000) {
 		cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
-		cur_cpu_spec->cpu_features |= CPU_FTR_P9_TLBIE_BUG;
 		cur_cpu_spec->cpu_features |= CPU_FTR_P9_TIDR;
 	}
 
+	update_tlbie_feature_flag(version);
 	/*
 	 * PKEY was not in the initial base or feature node
 	 * specification, but it should become optional in the next
-- 
2.21.0