powerpc/mm: Wire up hpte_removebolted for powernv

Adds support for removing bolted (i.e kernel linear mapping) mappings on
powernv. This is needed to support memory hot unplug operations which
are required for the teardown of DAX/PMEM devices.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index fbd1acc3b8d91f88006c09c233402f5151f90866..3848af167df9de4b183d7cb8472b5d20ce97d0a4 100644 (file)
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -413,6 +413,38 @@ static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
        tlbie(vpn, psize, psize, ssize, 0);
 }
 
+/*
+ * Remove a bolted kernel entry. Memory hotplug uses this.
+ *
+ * No need to lock here because we should be the only user.
+ */
+static int native_hpte_removebolted(unsigned long ea, int psize, int ssize)
+{
+       unsigned long vpn;
+       unsigned long vsid;
+       long slot;
+       struct hash_pte *hptep;
+
+       vsid = get_kernel_vsid(ea, ssize);
+       vpn = hpt_vpn(ea, vsid, ssize);
+
+       slot = native_hpte_find(vpn, psize, ssize);
+       if (slot == -1)
+               return -ENOENT;
+
+       hptep = htab_address + slot;
+
+       VM_WARN_ON(!(be64_to_cpu(hptep->v) & HPTE_V_BOLTED));
+
+       /* Invalidate the hpte */
+       hptep->v = 0;
+
+       /* Invalidate the TLB */
+       tlbie(vpn, psize, psize, ssize, 0);
+       return 0;
+}
+
+
 static void native_hpte_invalidate(unsigned long slot, unsigned long vpn,
                                   int bpsize, int apsize, int ssize, int local)
 {
@@ -731,6 +763,7 @@ void __init hpte_init_native(void)
        mmu_hash_ops.hpte_invalidate    = native_hpte_invalidate;
        mmu_hash_ops.hpte_updatepp      = native_hpte_updatepp;
        mmu_hash_ops.hpte_updateboltedpp = native_hpte_updateboltedpp;
+       mmu_hash_ops.hpte_removebolted = native_hpte_removebolted;
        mmu_hash_ops.hpte_insert        = native_hpte_insert;
        mmu_hash_ops.hpte_remove        = native_hpte_remove;
        mmu_hash_ops.hpte_clear_all     = native_hpte_clear;