[added,to,3.12-stable] mm: export symbol dependencies of is_zero_pfn()

Message ID 20161125082518.26936-3-jslaby@suse.cz
State New
Headers show

Commit Message

Jiri Slaby Nov. 25, 2016, 8:25 a.m.
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.


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commit 0b70068e47e8f0c813a902dc3d6def601fd15acb upstream.

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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
 arch/mips/mm/init.c | 1 +
 arch/s390/mm/init.c | 1 +
 mm/memory.c         | 2 ++
 3 files changed, 4 insertions(+)

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index e205ef598e97..c247cf5a31cb 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -74,6 +74,7 @@ 
 unsigned long empty_zero_page, zero_page_mask;
  * Not static inline because used by IP27 special magic initialization code
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index ad446b0c55b6..1b30d5488f82 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -43,6 +43,7 @@  pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
 unsigned long empty_zero_page, zero_page_mask;
 static void __init setup_zero_pages(void)
diff --git a/mm/memory.c b/mm/memory.c
index a0c9c6cb59d1..f5744269a454 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -116,6 +116,8 @@  __setup("norandmaps", disable_randmaps);
 unsigned long zero_pfn __read_mostly;
 unsigned long highest_memmap_pfn __read_mostly;
  * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()