summaryrefslogtreecommitdiff
path: root/include/asm-generic/pgtable.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/asm-generic/pgtable.h')
-rw-r--r--include/asm-generic/pgtable.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index bfd87685fc1f..a59ff51b0166 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -7,6 +7,16 @@
#include <linux/mm_types.h>
#include <linux/bug.h>
+/*
+ * On almost all architectures and configurations, 0 can be used as the
+ * upper ceiling to free_pgtables(): on many architectures it has the same
+ * effect as using TASK_SIZE. However, there is one configuration which
+ * must impose a more careful limit, to avoid freeing kernel pgtables.
+ */
+#ifndef USER_PGTABLES_CEILING
+#define USER_PGTABLES_CEILING 0UL
+#endif
+
#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
extern int ptep_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep,