X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=mm%2Futil.c;h=f5712e8964be8a8da2c521361dee71c123689428;hb=66f998f611897319b555364cefd5d6e88a205866;hp=7c35ad95f92756d1473bbc2ae658f5bb27de2ca9;hpb=950f564b707ca1b1c5bb94cd1e7d2a0702bfcadc;p=~andy%2Flinux

diff --git a/mm/util.c b/mm/util.c
index 7c35ad95f92..f5712e8964b 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -186,6 +186,27 @@ void kzfree(const void *p)
 }
 EXPORT_SYMBOL(kzfree);
 
+int kern_ptr_validate(const void *ptr, unsigned long size)
+{
+	unsigned long addr = (unsigned long)ptr;
+	unsigned long min_addr = PAGE_OFFSET;
+	unsigned long align_mask = sizeof(void *) - 1;
+
+	if (unlikely(addr < min_addr))
+		goto out;
+	if (unlikely(addr > (unsigned long)high_memory - size))
+		goto out;
+	if (unlikely(addr & align_mask))
+		goto out;
+	if (unlikely(!kern_addr_valid(addr)))
+		goto out;
+	if (unlikely(!kern_addr_valid(addr + size - 1)))
+		goto out;
+	return 1;
+out:
+	return 0;
+}
+
 /*
  * strndup_user - duplicate an existing string from user space
  * @s: The string to duplicate
@@ -220,7 +241,7 @@ char *strndup_user(const char __user *s, long n)
 }
 EXPORT_SYMBOL(strndup_user);
 
-#ifndef HAVE_ARCH_PICK_MMAP_LAYOUT
+#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
 void arch_pick_mmap_layout(struct mm_struct *mm)
 {
 	mm->mmap_base = TASK_UNMAPPED_BASE;