Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x32 support for x86-64 from Ingo Molnar:
 "This tree introduces the X32 binary format and execution mode for x86:
  32-bit data space binaries using 64-bit instructions and 64-bit kernel
  syscalls.

  This allows applications whose working set fits into a 32 bits address
  space to make use of 64-bit instructions while using a 32-bit address
  space with shorter pointers, more compressed data structures, etc."

Fix up trivial context conflicts in arch/x86/{Kconfig,vdso/vma.c}

* 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
  x32: Fix alignment fail in struct compat_siginfo
  x32: Fix stupid ia32/x32 inversion in the siginfo format
  x32: Add ptrace for x32
  x32: Switch to a 64-bit clock_t
  x32: Provide separate is_ia32_task() and is_x32_task() predicates
  x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls
  x86/x32: Fix the binutils auto-detect
  x32: Warn and disable rather than error if binutils too old
  x32: Only clear TIF_X32 flag once
  x32: Make sure TS_COMPAT is cleared for x32 tasks
  fs: Remove missed ->fds_bits from cessation use of fd_set structs internally
  fs: Fix close_on_exec pointer in alloc_fdtable
  x32: Drop non-__vdso weak symbols from the x32 VDSO
  x32: Fix coding style violations in the x32 VDSO code
  x32: Add x32 VDSO support
  x32: Allow x32 to be configured
  x32: If configured, add x32 system calls to system call tables
  x32: Handle process creation
  x32: Signal-related system calls
  x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h>
  ...

1 files changed, 17 insertions, 4 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index abfb953c131d..1d14cc6b79ad 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2163,9 +2163,9 @@ config IA32_EMULATION
         depends on X86_64
         select COMPAT_BINFMT_ELF
         ---help---
-          Include code to run 32-bit programs under a 64-bit kernel. You should
-          likely turn this on, unless you're 100% sure that you don't have any
-          32-bit programs left.
+          Include code to run legacy 32-bit programs under a
+          64-bit kernel. You should likely turn this on, unless you're
+          100% sure that you don't have any 32-bit programs left.
 
 config IA32_AOUT
         tristate "IA32 a.out support"
@@ -2173,9 +2173,22 @@ config IA32_AOUT
         ---help---
           Support old a.out binaries in the 32bit emulation.
 
+config X86_X32
+        bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
+        depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
+        ---help---
+          Include code to run binaries for the x32 native 32-bit ABI
+          for 64-bit processors.  An x32 process gets access to the
+          full 64-bit register file and wide data path while leaving
+          pointers at 32 bits for smaller memory footprint.
+
+          You will need a recent binutils (2.22 or later) with
+          elf32_x86_64 support enabled to compile a kernel with this
+          option set.
+
 config COMPAT
         def_bool y
-        depends on IA32_EMULATION
+        depends on IA32_EMULATION || X86_X32
         select ARCH_WANT_OLD_COMPAT_IPC
 
 config COMPAT_FOR_U64_ALIGNMENT