From: Anton Blanchard <anton@xxxxxxxxx>
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: Rashmica Gupta <rashmica.g@xxxxxxxxx>
Signed-off-by: Anton Blanchard <anton@xxxxxxxxx>
Signed-off-by: Oliver O'Halloran <oohall@xxxxxxxxx>
---
v1 -> v2: Fixed the commit author
Added VM_WARN_ON() if we attempt to remove an unbolted hpte
---
arch/powerpc/mm/hash_native_64.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index 65bb8f33b399..b534d041cfe8 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -407,6 +407,38 @@ 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)
{
@@ -725,6 +757,7 @@ 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;
--
2.9.3
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