mm/vmalloc: track which page-table levels were modified

Track at which levels in the page-table entries were modified by
vmap/vunmap.

After the page-table has been modified, use that information do decide
whether the new arch_sync_kernel_mappings() needs to be called.

[[email protected]: map_kernel_range_noflush() needs the arch_sync_kernel_mappings() call]
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "H . Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Steven Rostedt (VMware) <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 3332926295d4..0efc35dc5b25 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -134,6 +134,22 @@ void vmalloc_sync_mappings(void);
 void vmalloc_sync_unmappings(void);
 
 /*
+ * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values
+ * and let generic vmalloc and ioremap code know when arch_sync_kernel_mappings()
+ * needs to be called.
+ */
+#ifndef ARCH_PAGE_TABLE_SYNC_MASK
+#define ARCH_PAGE_TABLE_SYNC_MASK 0
+#endif
+
+/*
+ * There is no default implementation for arch_sync_kernel_mappings(). It is
+ * relied upon the compiler to optimize calls out if ARCH_PAGE_TABLE_SYNC_MASK
+ * is 0.
+ */
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end);
+
+/*
  *	Lowlevel-APIs (not for driver use!)
  */