Re: [PATCH] x86/vsyscall/64: Drop "native" vsyscalls

2018-03-07 Thread Andy Lutomirski
On Wed, Mar 7, 2018 at 7:31 PM, Dominik Brodowski wrote: > On Wed, Mar 07, 2018 at 11:21:46AM -0800, Kees Cook wrote: >> On Wed, Mar 7, 2018 at 11:12 AM, Andy Lutomirski wrote: >> > Since Linux 3.2, vsyscalls have been deprecated and slow. From 3.2 >> > on, Linux had three vsyscall modes: "nativ

Re: [PATCH] x86/vsyscall/64: Drop "native" vsyscalls

2018-03-07 Thread Dominik Brodowski
On Wed, Mar 07, 2018 at 11:21:46AM -0800, Kees Cook wrote: > On Wed, Mar 7, 2018 at 11:12 AM, Andy Lutomirski wrote: > > Since Linux 3.2, vsyscalls have been deprecated and slow. From 3.2 > > on, Linux had three vsyscall modes: "native", "emulate", and "none". > > > > "emulate" is the default. A

Re: [PATCH] x86/vsyscall/64: Drop "native" vsyscalls

2018-03-07 Thread Linus Torvalds
On Wed, Mar 7, 2018 at 11:12 AM, Andy Lutomirski wrote: > > For all practical purposes, "native" was really just a chicken bit > in case something went wrong with the emulation. It's been over six > years, and nothing has gone wrong. Delete it. Ack. I guess we';ll hear if anybody might still u

Re: [PATCH] x86/vsyscall/64: Drop "native" vsyscalls

2018-03-07 Thread Kees Cook
On Wed, Mar 7, 2018 at 11:12 AM, Andy Lutomirski wrote: > Since Linux 3.2, vsyscalls have been deprecated and slow. From 3.2 > on, Linux had three vsyscall modes: "native", "emulate", and "none". > > "emulate" is the default. All known user programs work correctly in > emulate mode, but vsyscall

[PATCH] x86/vsyscall/64: Drop "native" vsyscalls

2018-03-07 Thread Andy Lutomirski
Since Linux 3.2, vsyscalls have been deprecated and slow. From 3.2 on, Linux had three vsyscall modes: "native", "emulate", and "none". "emulate" is the default. All known user programs work correctly in emulate mode, but vsyscalls turn into page faults and are emulated. This is very slow. In "