Dec. 13, 2017
2:59 a.m.
On Tue, 12 Dec 2017 20:14:35 +0100, Damian Tometzki said:
How are the bits (in brackets) calculated in the virtual memory map ?
For x86_64 architecture, the 47 comes from the fact that currently shipping CPUs have an architected 48 bit wide memory address bus, and the fact that Linux does a "userspace lower half, kernel upper half" division of the address space. Recently, a patch for 5-level page tables went it, to support upcoming hardware that provides hardware support for 56-bit memory address buses.