Messages in this thread | | | Subject | Re: [PATCH v2 4/8] x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature | From | Tim Chen <> | Date | Tue, 9 Jan 2018 09:55:30 -0800 |
| |
On 01/09/2018 02:40 AM, Thomas Gleixner wrote: > On Mon, 8 Jan 2018, Peter Zijlstra wrote: >> On Mon, Jan 08, 2018 at 09:28:12AM -0800, Tim Chen wrote: >>> On 01/08/2018 08:14 AM, Peter Zijlstra wrote: >>>> On Mon, Jan 08, 2018 at 01:47:07PM +0100, Peter Zijlstra wrote: >>>>>> a good suggestion, but we encountered some issues with it either >>>>>> crashing the kernel at boot or not properly turning on/off. >>>> >>>> The below boots, but I lack stuff to test the enabling. >>> >>> Peter, >>> >>> Thanks. Will give it a spin. One other concern is if >>> JUMP_LABEL is not configured, this may not work, and >>> we may still need fall back to a control variable. >> >> Urgh yes.. I always forget about that case. Will the retpoline crud be >> backported to a GCC old enough to not have asm-goto? If not, we could >> make all of this simply require asm-goto. > > No, ifs and buts, really. > > This wants to be a jump label and we set the requirements here. I'm tired > of this completely bogus crap just to support some archaic version of GCC. > > This is messy enough and no, this whole we need a control variable nonsense > is just not going to happen. > >
Thomas,
I'll be sending an updated patchset with boot option opt in for ibrs and leave the control varaible out. I agree that we can worry about the control variable later.
Thanks.
Tim
| |