The x32 ABI promises to make the advantages of x86-64 CPUs accessible while avoiding the overhead that comes with 64-bit code. Version 3.4 of the kernel will improve the power-saving capabilities of Xen. The new Yama module prevents processes from examining the memory of other processes.
Last weekend, Linus Torvalds published the fifth release candidate for Linux 3.4; one to three further RCs will likely follow before the final release of this kernel version, which is expected to arrive in the second half of May.
From Linux 3.4, kernels that are compiled for x86-64/x64 processors can offer an "x32" ABI (Application Binary Interface) to programs (1 and others). Programs compiled for this ABI can access the 64-bit registers and data paths of 64-bit processors, but they only use 32-bit pointers – which are sufficient for many typical tasks and use less memory than 64-bit pointers.
Broadly speaking, this allows programs which are compiled for the x32 ABI to avoid the overhead that comes with full 64-bit operation while enabling them to benefit from some of the major advantages of 64-bit x86 processors. The latter is not possible when 32-bit x86 programs (x86-32/ix86) are executed on x86-64 distributions, a capability Linux has offered since the early days of its 64-bit x86 support.