Re: [Xen-devel] [kernel-hardening] Re: x86: PIE support and option to extend KASLR randomization

2017-08-28 Thread Pavel Machek
Hi! > > + The kernel and modules will generate slightly more assembly (1 to > > 2% > > + increase on the .text sections). The vmlinux binary will be > > + significantly smaller due to less relocations. > > > > ... but describing a 1-2% kernel text size increase as

Re: [Xen-devel] [kernel-hardening] Re: x86: PIE support and option to extend KASLR randomization

2017-08-27 Thread Boris Lukashev
On Fri, Aug 25, 2017 at 11:38 AM, Christopher Lameter wrote: > > > On Thu, 17 Aug 2017, Boris Lukashev wrote: > >> Is the expectation then to have security functions also decrease size >> and operational latency? Seems a bit unrealistic if so. >> 1-2% performance hit on systems

Re: [Xen-devel] [kernel-hardening] Re: x86: PIE support and option to extend KASLR randomization

2017-08-25 Thread Christopher Lameter
On Thu, 17 Aug 2017, Boris Lukashev wrote: > Is the expectation then to have security functions also decrease size > and operational latency? Seems a bit unrealistic if so. > 1-2% performance hit on systems which have become at least several > hundred % faster over recent years is not a

Re: [Xen-devel] [kernel-hardening] Re: x86: PIE support and option to extend KASLR randomization

2017-08-17 Thread Boris Lukashev
On Thu, Aug 17, 2017 at 4:09 AM, Ingo Molnar wrote: > > * Thomas Garnier wrote: > >> > > -model=small/medium assume you are on the low 32-bit. It generates >> > > instructions where the virtual addresses have the high 32-bit to be zero. >> > >> > How are

Re: [Xen-devel] [kernel-hardening] Re: x86: PIE support and option to extend KASLR randomization

2017-07-19 Thread Kees Cook
On Wed, Jul 19, 2017 at 7:08 AM, Christopher Lameter wrote: > On Tue, 18 Jul 2017, Thomas Garnier wrote: > >> Performance/Size impact: >> Hackbench (50% and 1600% loads): >> - PIE enabled: 7% to 8% on half load, 10% on heavy load. >> slab_test (average of 10 runs): >> - PIE