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-rw-r--r--drivers/char/random.c32
-rw-r--r--include/linux/mm.h1
-rw-r--r--include/linux/random.h2
-rw-r--r--mm/util.c32
4 files changed, 33 insertions, 34 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 16b39d2dead7..36183b0cf923 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -573,38 +573,6 @@ int __cold random_prepare_cpu(unsigned int cpu)
}
#endif
-/**
- * randomize_page - Generate a random, page aligned address
- * @start: The smallest acceptable address the caller will take.
- * @range: The size of the area, starting at @start, within which the
- * random address must fall.
- *
- * If @start + @range would overflow, @range is capped.
- *
- * NOTE: Historical use of randomize_range, which this replaces, presumed that
- * @start was already page aligned. We now align it regardless.
- *
- * Return: A page aligned address within [start, start + range). On error,
- * @start is returned.
- */
-unsigned long randomize_page(unsigned long start, unsigned long range)
-{
- if (!PAGE_ALIGNED(start)) {
- range -= PAGE_ALIGN(start) - start;
- start = PAGE_ALIGN(start);
- }
-
- if (start > ULONG_MAX - range)
- range = ULONG_MAX - start;
-
- range >>= PAGE_SHIFT;
-
- if (range == 0)
- return start;
-
- return start + (get_random_long() % range << PAGE_SHIFT);
-}
-
/**********************************************************************
*
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9f44254af8ce..b0183450e484 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2677,6 +2677,7 @@ extern int install_special_mapping(struct mm_struct *mm,
unsigned long flags, struct page **pages);
unsigned long randomize_stack_top(unsigned long stack_top);
+unsigned long randomize_page(unsigned long start, unsigned long range);
extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
diff --git a/include/linux/random.h b/include/linux/random.h
index d2360b2825b6..fae0c84027fd 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -72,8 +72,6 @@ static inline unsigned long get_random_canary(void)
return get_random_long() & CANARY_MASK;
}
-unsigned long randomize_page(unsigned long start, unsigned long range);
-
int __init random_init(const char *command_line);
bool rng_is_initialized(void);
bool rng_has_arch_random(void);
diff --git a/mm/util.c b/mm/util.c
index 3492a9e81aa3..ac63e5ca8b21 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -343,6 +343,38 @@ unsigned long randomize_stack_top(unsigned long stack_top)
#endif
}
+/**
+ * randomize_page - Generate a random, page aligned address
+ * @start: The smallest acceptable address the caller will take.
+ * @range: The size of the area, starting at @start, within which the
+ * random address must fall.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * NOTE: Historical use of randomize_range, which this replaces, presumed that
+ * @start was already page aligned. We now align it regardless.
+ *
+ * Return: A page aligned address within [start, start + range). On error,
+ * @start is returned.
+ */
+unsigned long randomize_page(unsigned long start, unsigned long range)
+{
+ if (!PAGE_ALIGNED(start)) {
+ range -= PAGE_ALIGN(start) - start;
+ start = PAGE_ALIGN(start);
+ }
+
+ if (start > ULONG_MAX - range)
+ range = ULONG_MAX - start;
+
+ range >>= PAGE_SHIFT;
+
+ if (range == 0)
+ return start;
+
+ return start + (get_random_long() % range << PAGE_SHIFT);
+}
+
#ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
unsigned long arch_randomize_brk(struct mm_struct *mm)
{