On Tue, May 23, 2017 at 2:05 PM, Oliver O'Halloran <oohall@xxxxxxxxx> wrote:
> 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;
> +}
> +
Reviewed-by: Balbir Singh <bsingharora@xxxxxxxxx>
Balbir Singh.
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