mm: export symbol dependencies of is_zero_pfn()
In order to make the static inline function is_zero_pfn() callable by
modules, export its symbol dependencies 'zero_pfn' and (for s390 and
mips) 'zero_page_mask'.
We need this for KVM, as CONFIG_KVM is a tristate for all supported
architectures except ARM and arm64, and testing a pfn whether it refers
to the zero page is required to correctly distinguish the zero page
from other special RAM ranges that may also have the PG_reserved bit
set, but need to be treated as MMIO memory.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/mm/memory.c b/mm/memory.c
index ab3537b..1fcf59a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -118,6 +118,8 @@
unsigned long zero_pfn __read_mostly;
unsigned long highest_memmap_pfn __read_mostly;
+EXPORT_SYMBOL(zero_pfn);
+
/*
* CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
*/