Index: docs/AMDGPUUsage.rst
===================================================================
--- docs/AMDGPUUsage.rst
+++ docs/AMDGPUUsage.rst
@@ -365,9 +365,11 @@
      ``e_ident[EI_CLASS]``      ``ELFCLASS64``
      ``e_ident[EI_DATA]``       ``ELFDATA2LSB``
      ``e_ident[EI_OSABI]``      ``ELFOSABI_AMDGPU_HSA`` or
-                                ``ELFOSABI_AMDGPU_PAL``
+                                ``ELFOSABI_AMDGPU_PAL`` or
+                                ``ELFOSABI_AMDGPU_MESA3D``
      ``e_ident[EI_ABIVERSION]`` ``ELFABIVERSION_AMDGPU_HSA`` or
-                                ``ELFABIVERSION_AMDGPU_PAL``
+                                ``ELFABIVERSION_AMDGPU_PAL`` or
+                                ``ELFABIVERSION_AMDGPU_MESA3D``
      ``e_type``                 ``ET_REL`` or ``ET_DYN``
      ``e_machine``              ``EM_AMDGPU``
      ``e_entry``                0
@@ -379,15 +381,17 @@
   .. table:: AMDGPU ELF Header Enumeration Values
      :name: amdgpu-elf-header-enumeration-values-table
 
-     ============================ =====
-     Name                         Value
-     ============================ =====
-     ``EM_AMDGPU``                224
-     ``ELFOSABI_AMDGPU_HSA``      64
-     ``ELFOSABI_AMDGPU_PAL``      65
-     ``ELFABIVERSION_AMDGPU_HSA`` 1
-     ``ELFABIVERSION_AMDGPU_PAL`` 0
-     ============================ =====
+     =============================== =====
+     Name                            Value
+     =============================== =====
+     ``EM_AMDGPU``                   224
+     ``ELFOSABI_AMDGPU_HSA``         64
+     ``ELFOSABI_AMDGPU_PAL``         65
+     ``ELFOSABI_AMDGPU_MESA3D``      66
+     ``ELFABIVERSION_AMDGPU_HSA``    1
+     ``ELFABIVERSION_AMDGPU_PAL``    0
+     ``ELFABIVERSION_AMDGPU_MESA3D`` 0
+     =============================== =====
 
 ``e_ident[EI_CLASS]``
   The ELF class is always ``ELFCLASS64``. The AMDGPU backend only supports 64
@@ -397,7 +401,7 @@
   All AMDGPU targets use ELFDATA2LSB for little-endian byte ordering.
 
 ``e_ident[EI_OSABI]``
-  One of two AMD GPU architecture specific OS ABI:
+  One of the following AMD GPU architecture specific OS ABIs:
 
   * ``ELFOSABI_AMDGPU_HSA`` is used to specify that the code object conforms to
     the AMD HSA runtime ABI [HSA]_.
@@ -405,6 +409,9 @@
   * ``ELFOSABI_AMDGPU_PAL`` is used to specify that the code object conforms to
     the AMD PAL runtime ABI.
 
+  * ``ELFOSABI_AMDGPU_MESA3D`` is used to specify that the code object conforms
+    to the AMD MESA runtime ABI.
+
 ``e_ident[EI_ABIVERSION]``
   The ABI version of the AMD GPU architecture specific OS ABI to which the code
   object conforms:
@@ -415,6 +422,9 @@
   * ``ELFABIVERSION_AMDGPU_PAL`` is used to specify the version of AMD PAL
     runtime ABI.
 
+  * ``ELFABIVERSION_AMDGPU_MESA3D`` is used to specify the version of AMD MESA
+    runtime ABI.
+
 ``e_type``
   Can be one of the following values:
 
Index: include/llvm/BinaryFormat/ELF.h
===================================================================
--- include/llvm/BinaryFormat/ELF.h
+++ include/llvm/BinaryFormat/ELF.h
@@ -335,30 +335,31 @@
 
 // OS ABI identification.
 enum {
-  ELFOSABI_NONE = 0,          // UNIX System V ABI
-  ELFOSABI_HPUX = 1,          // HP-UX operating system
-  ELFOSABI_NETBSD = 2,        // NetBSD
-  ELFOSABI_GNU = 3,           // GNU/Linux
-  ELFOSABI_LINUX = 3,         // Historical alias for ELFOSABI_GNU.
-  ELFOSABI_HURD = 4,          // GNU/Hurd
-  ELFOSABI_SOLARIS = 6,       // Solaris
-  ELFOSABI_AIX = 7,           // AIX
-  ELFOSABI_IRIX = 8,          // IRIX
-  ELFOSABI_FREEBSD = 9,       // FreeBSD
-  ELFOSABI_TRU64 = 10,        // TRU64 UNIX
-  ELFOSABI_MODESTO = 11,      // Novell Modesto
-  ELFOSABI_OPENBSD = 12,      // OpenBSD
-  ELFOSABI_OPENVMS = 13,      // OpenVMS
-  ELFOSABI_NSK = 14,          // Hewlett-Packard Non-Stop Kernel
-  ELFOSABI_AROS = 15,         // AROS
-  ELFOSABI_FENIXOS = 16,      // FenixOS
-  ELFOSABI_CLOUDABI = 17,     // Nuxi CloudABI
-  ELFOSABI_C6000_ELFABI = 64, // Bare-metal TMS320C6000
-  ELFOSABI_C6000_LINUX = 65,  // Linux TMS320C6000
-  ELFOSABI_AMDGPU_HSA = 64,   // AMD HSA runtime
-  ELFOSABI_AMDGPU_PAL = 65,   // AMD PAL runtime
-  ELFOSABI_ARM = 97,          // ARM
-  ELFOSABI_STANDALONE = 255   // Standalone (embedded) application
+  ELFOSABI_NONE = 0,           // UNIX System V ABI
+  ELFOSABI_HPUX = 1,           // HP-UX operating system
+  ELFOSABI_NETBSD = 2,         // NetBSD
+  ELFOSABI_GNU = 3,            // GNU/Linux
+  ELFOSABI_LINUX = 3,          // Historical alias for ELFOSABI_GNU.
+  ELFOSABI_HURD = 4,           // GNU/Hurd
+  ELFOSABI_SOLARIS = 6,        // Solaris
+  ELFOSABI_AIX = 7,            // AIX
+  ELFOSABI_IRIX = 8,           // IRIX
+  ELFOSABI_FREEBSD = 9,        // FreeBSD
+  ELFOSABI_TRU64 = 10,         // TRU64 UNIX
+  ELFOSABI_MODESTO = 11,       // Novell Modesto
+  ELFOSABI_OPENBSD = 12,       // OpenBSD
+  ELFOSABI_OPENVMS = 13,       // OpenVMS
+  ELFOSABI_NSK = 14,           // Hewlett-Packard Non-Stop Kernel
+  ELFOSABI_AROS = 15,          // AROS
+  ELFOSABI_FENIXOS = 16,       // FenixOS
+  ELFOSABI_CLOUDABI = 17,      // Nuxi CloudABI
+  ELFOSABI_C6000_ELFABI = 64,  // Bare-metal TMS320C6000
+  ELFOSABI_C6000_LINUX = 65,   // Linux TMS320C6000
+  ELFOSABI_AMDGPU_HSA = 64,    // AMD HSA runtime
+  ELFOSABI_AMDGPU_PAL = 65,    // AMD PAL runtime
+  ELFOSABI_AMDGPU_MESA3D = 66, // AMD GCN GPUs (GFX6+) for MESA runtime
+  ELFOSABI_ARM = 97,           // ARM
+  ELFOSABI_STANDALONE = 255    // Standalone (embedded) application
 };
 
 #define ELF_RELOC(name, value) name = value,
Index: lib/ObjectYAML/ELFYAML.cpp
===================================================================
--- lib/ObjectYAML/ELFYAML.cpp
+++ lib/ObjectYAML/ELFYAML.cpp
@@ -264,6 +264,7 @@
   ECase(ELFOSABI_C6000_LINUX);
   ECase(ELFOSABI_AMDGPU_HSA);
   ECase(ELFOSABI_AMDGPU_PAL);
+  ECase(ELFOSABI_AMDGPU_MESA3D);
   ECase(ELFOSABI_ARM);
   ECase(ELFOSABI_STANDALONE);
 #undef ECase
Index: test/Object/AMDGPU/elf64-amdgcn-mesa3d-definitions.yaml
===================================================================
--- /dev/null
+++ test/Object/AMDGPU/elf64-amdgcn-mesa3d-definitions.yaml
@@ -0,0 +1,21 @@
+# RUN: yaml2obj %s > %t.o
+# RUN: llvm-readobj -s -file-headers %t.o | FileCheck %s
+
+# CHECK: Format: ELF64-amdgpu
+# CHECK: Arch: amdgcn
+# CHECK: ElfHeader {
+# CHECK:   Ident {
+# CHECK:     OS/ABI: MESA3D (0x42)
+# CHECK:     ABIVersion: 0
+# CHECK:   }
+# CHECK:   Machine: EM_AMDGPU (0xE0)
+# CHECK: }
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_AMDGPU
+  OSABI:   ELFOSABI_AMDGPU_MESA3D
+...
Index: tools/llvm-readobj/ELFDumper.cpp
===================================================================
--- tools/llvm-readobj/ELFDumper.cpp
+++ tools/llvm-readobj/ELFDumper.cpp
@@ -828,8 +828,9 @@
 };
 
 static const EnumEntry<unsigned> AMDGPUElfOSABI[] = {
-  {"AMDHSA", "AMDGPU - HSA", ELF::ELFOSABI_AMDGPU_HSA},
-  {"AMDPAL", "AMDGPU - PAL", ELF::ELFOSABI_AMDGPU_PAL}
+  {"AMDHSA", "AMDGPU - HSA",    ELF::ELFOSABI_AMDGPU_HSA},
+  {"AMDPAL", "AMDGPU - PAL",    ELF::ELFOSABI_AMDGPU_PAL},
+  {"MESA3D", "AMDGPU - MESA3D", ELF::ELFOSABI_AMDGPU_MESA3D}
 };
 
 static const EnumEntry<unsigned> ElfMachineType[] = {