mm, x86: Add ARCH_HAS_ZONE_DEVICE to Kconfig

Currently ZONE_DEVICE depends on X86_64 and this will get unwieldly as
new architectures (and platforms) get ZONE_DEVICE support. Move to an
arch selected Kconfig option to save us the trouble.

Cc: linux-mm@kvack.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

2 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4ccfacc7232a..32903e30e347 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -59,6 +59,7 @@ config X86
         select ARCH_HAS_STRICT_KERNEL_RWX
         select ARCH_HAS_STRICT_MODULE_RWX
         select ARCH_HAS_UBSAN_SANITIZE_ALL
+        select ARCH_HAS_ZONE_DEVICE             if X86_64
         select ARCH_HAVE_NMI_SAFE_CMPXCHG
         select ARCH_MIGHT_HAVE_ACPI_PDC         if ACPI
         select ARCH_MIGHT_HAVE_PC_PARPORT
diff --git a/mm/Kconfig b/mm/Kconfig
index beb7a455915d..790e52a8a486 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -683,12 +683,16 @@ config IDLE_PAGE_TRACKING
 
           See Documentation/vm/idle_page_tracking.txt for more details.
 
+# arch_add_memory() comprehends device memory
+config ARCH_HAS_ZONE_DEVICE
+        bool
+
 config ZONE_DEVICE
         bool "Device memory (pmem, etc...) hotplug support"
         depends on MEMORY_HOTPLUG
         depends on MEMORY_HOTREMOVE
         depends on SPARSEMEM_VMEMMAP
-        depends on X86_64 #arch_add_memory() comprehends device memory
+        depends on ARCH_HAS_ZONE_DEVICE
 
         help
           Device memory hotplug support allows for establishing pmem,