diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/mman.h b/sysdeps/unix/sysv/linux/aarch64/bits/mman.h
index 9ad8a60..5775660 100644
--- a/sysdeps/unix/sysv/linux/aarch64/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/aarch64/bits/mman.h
@@ -38,6 +38,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 
diff --git a/sysdeps/unix/sysv/linux/alpha/bits/mman.h b/sysdeps/unix/sysv/linux/alpha/bits/mman.h
index 935804b..3abfd84 100644
--- a/sysdeps/unix/sysv/linux/alpha/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/alpha/bits/mman.h
@@ -36,6 +36,8 @@
 # define MAP_NONBLOCK	  0x40000	/* Do not block on IO.  */
 # define MAP_STACK	  0x80000	/* Allocation is for a stack.  */
 # define MAP_HUGETLB	  0x100000	/* Create huge page mapping.  */
+# define MAP_FIXED_NOREPLACE 0x200000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Flags for `mlockall'.  */
diff --git a/sysdeps/unix/sysv/linux/arm/bits/mman.h b/sysdeps/unix/sysv/linux/arm/bits/mman.h
index be71c82..63813dc 100644
--- a/sysdeps/unix/sysv/linux/arm/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/arm/bits/mman.h
@@ -36,6 +36,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/hppa/bits/mman.h b/sysdeps/unix/sysv/linux/hppa/bits/mman.h
index 380be7b..1d2a175 100644
--- a/sysdeps/unix/sysv/linux/hppa/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/hppa/bits/mman.h
@@ -62,6 +62,8 @@
 # define MAP_NONBLOCK	0x20000		/* Do not block on IO */
 # define MAP_STACK	0x40000		/* Create for process/thread stacks */
 # define MAP_HUGETLB	0x80000		/* Create a huge page mapping */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Flags to "msync"  */
diff --git a/sysdeps/unix/sysv/linux/ia64/bits/mman.h b/sysdeps/unix/sysv/linux/ia64/bits/mman.h
index 0f00a1a..51071fd 100644
--- a/sysdeps/unix/sysv/linux/ia64/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/ia64/bits/mman.h
@@ -37,6 +37,8 @@
 # define MAP_HUGETLB	  0x40000	/* Create huge page mapping.  */
 # define MAP_SYNC	  0x80000	/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/m68k/bits/mman.h b/sysdeps/unix/sysv/linux/m68k/bits/mman.h
index 80cc2a6..8d355fe 100644
--- a/sysdeps/unix/sysv/linux/m68k/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/m68k/bits/mman.h
@@ -36,6 +36,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/microblaze/bits/mman.h b/sysdeps/unix/sysv/linux/microblaze/bits/mman.h
index 8ca77b6..fe1b376 100644
--- a/sysdeps/unix/sysv/linux/microblaze/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/microblaze/bits/mman.h
@@ -38,6 +38,8 @@
 # define MAP_HUGETLB        0x40000     /* Create huge page mapping.  */
 # define MAP_SYNC           0x80000	/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/mips/bits/mman.h b/sysdeps/unix/sysv/linux/mips/bits/mman.h
index ed8287f..102bc6d 100644
--- a/sysdeps/unix/sysv/linux/mips/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/mips/bits/mman.h
@@ -34,6 +34,8 @@
 # define MAP_NONBLOCK   0x20000         /* do not block on IO */
 # define MAP_STACK	0x40000		/* Allocation is for a stack.  */
 # define MAP_HUGETLB	0x80000		/* Create huge page mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 #define __MAP_ANONYMOUS 0x0800
diff --git a/sysdeps/unix/sysv/linux/nios2/bits/mman.h b/sysdeps/unix/sysv/linux/nios2/bits/mman.h
index 987e479..50f92b4 100644
--- a/sysdeps/unix/sysv/linux/nios2/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/nios2/bits/mman.h
@@ -38,6 +38,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/powerpc/bits/mman.h b/sysdeps/unix/sysv/linux/powerpc/bits/mman.h
index b8a01fa..e652467 100644
--- a/sysdeps/unix/sysv/linux/powerpc/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/powerpc/bits/mman.h
@@ -36,6 +36,8 @@
 # define MAP_NONBLOCK	0x10000		/* Do not block on IO.  */
 # define MAP_STACK	0x20000		/* Allocation is for a stack.  */
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Flags for `mlockall'.  */
diff --git a/sysdeps/unix/sysv/linux/riscv/bits/mman.h b/sysdeps/unix/sysv/linux/riscv/bits/mman.h
index 8425772..c01fb00 100644
--- a/sysdeps/unix/sysv/linux/riscv/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/riscv/bits/mman.h
@@ -32,6 +32,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/s390/bits/mman.h b/sysdeps/unix/sysv/linux/s390/bits/mman.h
index cdd7a63..f103c1a 100644
--- a/sysdeps/unix/sysv/linux/s390/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/s390/bits/mman.h
@@ -37,6 +37,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/sh/bits/mman.h b/sysdeps/unix/sysv/linux/sh/bits/mman.h
index e22be10..9015957 100644
--- a/sysdeps/unix/sysv/linux/sh/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/sh/bits/mman.h
@@ -36,6 +36,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
diff --git a/sysdeps/unix/sysv/linux/sparc/bits/mman.h b/sysdeps/unix/sysv/linux/sparc/bits/mman.h
index f0a4797..3a3ffb9 100644
--- a/sysdeps/unix/sysv/linux/sparc/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/sparc/bits/mman.h
@@ -36,6 +36,8 @@
 # define MAP_NONBLOCK	0x10000		/* Do not block on IO.  */
 # define MAP_STACK	0x20000		/* Allocation is for a stack.  */
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Flags for `mlockall'.  */
diff --git a/sysdeps/unix/sysv/linux/x86/bits/mman.h b/sysdeps/unix/sysv/linux/x86/bits/mman.h
index ebfc0c7..d897b8a 100644
--- a/sysdeps/unix/sysv/linux/x86/bits/mman.h
+++ b/sysdeps/unix/sysv/linux/x86/bits/mman.h
@@ -41,6 +41,8 @@
 # define MAP_HUGETLB	0x40000		/* Create huge page mapping.  */
 # define MAP_SYNC	0x80000		/* Perform synchronous page
 					   faults for the mapping.  */
+# define MAP_FIXED_NOREPLACE 0x100000	/* MAP_FIXED but do not unmap
+					   underlying mapping.  */
 #endif
 
 /* Include generic Linux declarations.  */
