From 269e829f48a0d0d27667abe25ca5c9e5b6ab08e2 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Date: Sun, 26 Jul 2020 18:55:17 +0530
Subject: [PATCH] powerpc/book3s64/pkey: Disable pkey on POWER6 and before
References: jsc#SLE-16556 bsc#1078248 FATE#322447
Patch-mainline: v5.9-rc1
Git-commit: 269e829f48a0d0d27667abe25ca5c9e5b6ab08e2
POWER6 only supports AMR update via privileged mode (MSR[PR] = 0,
SPRN_AMR=29) The PR=1 (userspace) alias for that SPR (SPRN_AMR=13) was
only supported from POWER7. Since we don't allow userspace modifying
of AMR value we should disable pkey support on P6 and before.
The hypervisor will still report pkey support via
"ibm,processor-storage-keys". Hence also check for P7 CPU_FTR bit to
decide on pkey support.
Fixes: f491fe3fb41e ("powerpc/book3s64/pkeys: Simplify the key initialization")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200726132517.399076-1-aneesh.kumar@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/mm/book3s64/pkeys.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c
index 792b36aa9619..69a6b87f2bb4 100644
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -73,6 +73,12 @@ static int scan_pkey_feature(void)
if (early_radix_enabled())
return 0;
+ /*
+ * Only P7 and above supports SPRN_AMR update with MSR[PR] = 1
+ */
+ if (!early_cpu_has_feature(CPU_FTR_ARCH_206))
+ return 0;
+
ret = of_scan_flat_dt(dt_scan_storage_keys, &pkeys_total);
if (ret == 0) {
/*
--
2.26.2