1 files changed, 62 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c
index 37eaccdf305..55bef160b9f 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -4,6 +4,7 @@
 #include <linux/module.h>
 #include <linux/err.h>
 #include <linux/sched.h>
+#include <linux/tracepoint.h>
 #include <asm/uaccess.h>
 
 /**
@@ -70,6 +71,36 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp)
 EXPORT_SYMBOL(kmemdup);
 
 /**
+ * memdup_user - duplicate memory region from user space
+ *
+ * @src: source address in user space
+ * @len: number of bytes to copy
+ *
+ * Returns an ERR_PTR() on failure.
+ */
+void *memdup_user(const void __user *src, size_t len)
+{
+	void *p;
+
+	/*
+	 * Always use GFP_KERNEL, since copy_from_user() can sleep and
+	 * cause pagefault, which makes it pointless to use GFP_NOFS
+	 * or GFP_ATOMIC.
+	 */
+	p = kmalloc_track_caller(len, GFP_KERNEL);
+	if (!p)
+		return ERR_PTR(-ENOMEM);
+
+	if (copy_from_user(p, src, len)) {
+		kfree(p);
+		return ERR_PTR(-EFAULT);
+	}
+
+	return p;
+}
+EXPORT_SYMBOL(memdup_user);
+
+/**
  * __krealloc - like krealloc() but don't free @p.
  * @p: object to reallocate memory for.
  * @new_size: how many bytes of memory are required.
@@ -192,6 +223,22 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 }
 #endif
 
+/**
+ * get_user_pages_fast() - pin user pages in memory
+ * @start:	starting user address
+ * @nr_pages:	number of pages from start to pin
+ * @write:	whether pages will be written to
+ * @pages:	array that receives pointers to the pages pinned.
+ *		Should be at least nr_pages long.
+ *
+ * Attempt to pin user pages in memory without taking mm->mmap_sem.
+ * If not successful, it will fall back to taking the lock and
+ * calling get_user_pages().
+ *
+ * Returns number of pages pinned. This may be fewer than the number
+ * requested. If nr_pages is 0 or negative, returns 0. If no pages
+ * were pinned, returns -errno.
+ */
 int __attribute__((weak)) get_user_pages_fast(unsigned long start,
 				int nr_pages, int write, struct page **pages)
 {
@@ -206,3 +253,18 @@ int __attribute__((weak)) get_user_pages_fast(unsigned long start,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(get_user_pages_fast);
+
+/* Tracepoints definitions. */
+DEFINE_TRACE(kmalloc);
+DEFINE_TRACE(kmem_cache_alloc);
+DEFINE_TRACE(kmalloc_node);
+DEFINE_TRACE(kmem_cache_alloc_node);
+DEFINE_TRACE(kfree);
+DEFINE_TRACE(kmem_cache_free);
+
+EXPORT_TRACEPOINT_SYMBOL(kmalloc);
+EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
+EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
+EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
+EXPORT_TRACEPOINT_SYMBOL(kfree);
+EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);