powerpc/book3s64/pkeys: Prevent key 1 modification from userspace.

Key 1 is marked reserved by ISA. Setup uamor to prevent userspace modification
of the same.

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/20200709032946.881753-8-aneesh.kumar@linux.ibm.com

diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c
index 2dea8c2..e2bf939 100644 (file)
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -183,6 +183,7 @@ static int pkey_initialize(void)
         * programming note.
         */
        reserved_allocation_mask |= (0x1 << 1);
+       default_uamor &= ~(0x3ul << pkeyshift(1));
 
        /*
         * Prevent the usage of OS reserved the keys. Update UAMOR