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-rw-r--r--arch/alpha/include/uapi/asm/mman.h1
-rw-r--r--arch/mips/include/uapi/asm/mman.h1
-rw-r--r--arch/parisc/include/uapi/asm/mman.h1
-rw-r--r--arch/xtensa/include/uapi/asm/mman.h1
-rw-r--r--include/uapi/asm-generic/mman-common.h1
-rw-r--r--mm/mmap.c11
6 files changed, 16 insertions, 0 deletions
diff --git a/arch/alpha/include/uapi/asm/mman.h b/arch/alpha/include/uapi/asm/mman.h
index 2dbdf59258d9..f9d4e6b6d4bd 100644
--- a/arch/alpha/include/uapi/asm/mman.h
+++ b/arch/alpha/include/uapi/asm/mman.h
@@ -32,6 +32,7 @@
#define MAP_NONBLOCK 0x40000 /* do not block on IO */
#define MAP_STACK 0x80000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x100000 /* create a huge page mapping */
+#define MAP_FIXED_NOREPLACE 0x200000/* MAP_FIXED which doesn't unmap underlying mapping */
#define MS_ASYNC 1 /* sync memory asynchronously */
#define MS_SYNC 2 /* synchronous memory sync */
diff --git a/arch/mips/include/uapi/asm/mman.h b/arch/mips/include/uapi/asm/mman.h
index 606e02ca4b6c..3035ca499cd8 100644
--- a/arch/mips/include/uapi/asm/mman.h
+++ b/arch/mips/include/uapi/asm/mman.h
@@ -50,6 +50,7 @@
#define MAP_NONBLOCK 0x20000 /* do not block on IO */
#define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x80000 /* create a huge page mapping */
+#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
/*
* Flags for msync
diff --git a/arch/parisc/include/uapi/asm/mman.h b/arch/parisc/include/uapi/asm/mman.h
index a056a642bb31..870fbf8c7088 100644
--- a/arch/parisc/include/uapi/asm/mman.h
+++ b/arch/parisc/include/uapi/asm/mman.h
@@ -26,6 +26,7 @@
#define MAP_NONBLOCK 0x20000 /* do not block on IO */
#define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x80000 /* create a huge page mapping */
+#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
#define MS_SYNC 1 /* synchronous memory sync */
#define MS_ASYNC 2 /* sync memory asynchronously */
diff --git a/arch/xtensa/include/uapi/asm/mman.h b/arch/xtensa/include/uapi/asm/mman.h
index 3e9d01ada81f..58f29a9d895d 100644
--- a/arch/xtensa/include/uapi/asm/mman.h
+++ b/arch/xtensa/include/uapi/asm/mman.h
@@ -57,6 +57,7 @@
#define MAP_NONBLOCK 0x20000 /* do not block on IO */
#define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x80000 /* create a huge page mapping */
+#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
# define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be
* uninitialized */
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index f8b134f5608f..4aa65a8d7e92 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -26,6 +26,7 @@
#else
# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
#endif
+#define MAP_FIXED_NOREPLACE 0x80000 /* MAP_FIXED which doesn't unmap underlying mapping */
/*
* Flags for mlock
diff --git a/mm/mmap.c b/mm/mmap.c
index f2154fc2548b..188f195883b9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1342,6 +1342,10 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
if (!(file && path_noexec(&file->f_path)))
prot |= PROT_EXEC;
+ /* force arch specific MAP_FIXED handling in get_unmapped_area */
+ if (flags & MAP_FIXED_NOREPLACE)
+ flags |= MAP_FIXED;
+
if (!(flags & MAP_FIXED))
addr = round_hint_to_min(addr);
@@ -1365,6 +1369,13 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
if (offset_in_page(addr))
return addr;
+ if (flags & MAP_FIXED_NOREPLACE) {
+ struct vm_area_struct *vma = find_vma(mm, addr);
+
+ if (vma && vma->vm_start <= addr)
+ return -EEXIST;
+ }
+
if (prot == PROT_EXEC) {
pkey = execute_only_pkey(mm);
if (pkey < 0)