powerpc: helper functions to initialize AMR, IAMR and UAMOR registers

Introduce  helper functions that can initialize the bits in the AMR,
IAMR and UAMOR register; the bits that correspond to the given pkey.

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index afa6d0d63f3242c9350cad4321584b5102e26e86..0cfe901594c7347a7cd3f475633dee0c6594089c 100644 (file)
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -12,6 +12,10 @@ bool pkey_execute_disable_supported;
 int  pkeys_total;              /* Total pkeys as per device tree */
 u32  initial_allocation_mask;  /* Bits set for reserved keys */
 
+#define AMR_BITS_PER_PKEY 2
+#define PKEY_REG_BITS (sizeof(u64)*8)
+#define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey+1) * AMR_BITS_PER_PKEY))
+
 int pkey_initialize(void)
 {
        int os_reserved, i;
@@ -103,3 +107,46 @@ static inline void write_uamor(u64 value)
 {
        mtspr(SPRN_UAMOR, value);
 }
+
+static inline void init_amr(int pkey, u8 init_bits)
+{
+       u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey));
+       u64 old_amr = read_amr() & ~((u64)(0x3ul) << pkeyshift(pkey));
+
+       write_amr(old_amr | new_amr_bits);
+}
+
+static inline void init_iamr(int pkey, u8 init_bits)
+{
+       u64 new_iamr_bits = (((u64)init_bits & 0x1UL) << pkeyshift(pkey));
+       u64 old_iamr = read_iamr() & ~((u64)(0x1ul) << pkeyshift(pkey));
+
+       write_iamr(old_iamr | new_iamr_bits);
+}
+
+static void pkey_status_change(int pkey, bool enable)
+{
+       u64 old_uamor;
+
+       /* Reset the AMR and IAMR bits for this key */
+       init_amr(pkey, 0x0);
+       init_iamr(pkey, 0x0);
+
+       /* Enable/disable key */
+       old_uamor = read_uamor();
+       if (enable)
+               old_uamor |= (0x3ul << pkeyshift(pkey));
+       else
+               old_uamor &= ~(0x3ul << pkeyshift(pkey));
+       write_uamor(old_uamor);
+}
+
+void __arch_activate_pkey(int pkey)
+{
+       pkey_status_change(pkey, true);
+}
+
+void __arch_deactivate_pkey(int pkey)
+{
+       pkey_status_change(pkey, false);
+}