linux-kernel - Re: TSC x86 fixes for LTS kernel 4.9.x

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Date:   Wed, 13 Dec 2017 16:07:12 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Greg KH <gregkh@...uxfoundation.org>
cc:     Dan Aloni <dan@...nelim.com>, stable@...r.kernel.org,
        Linux Kernel List <linux-kernel@...r.kernel.org>,
        Bin Gao <bin.gao@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: TSC x86 fixes for LTS kernel 4.9.x

On Wed, 13 Dec 2017, Greg KH wrote:
> On Wed, Dec 13, 2017 at 11:45:20AM +0200, Dan Aloni wrote:
> > # git log 8c9b9d87b855 --oneline -n 19 --reverse --pretty="%h # %s" | awk -F" " '{print "git cherry-pick -x " $0}'
> > 
> > git cherry-pick -x 47c95a46d0fa # x86/tsc: Add X86_FEATURE_TSC_KNOWN_FREQ flag
> > git cherry-pick -x 4ca4df0b7eb0 # x86/tsc: Mark TSC frequency determined by CPUID as known
> > git cherry-pick -x 4635fdc696a8 # x86/tsc: Mark Intel ATOM_GOLDMONT TSC reliable
> > git cherry-pick -x f3a02ecebed7 # x86/tsc: Set TSC_KNOWN_FREQ and TSC_RELIABLE flags on Intel Atom SoCs
> > git cherry-pick -x 984fecebda3b # x86/tsc: Finalize the split of the TSC_RELIABLE flag
> > git cherry-pick -x 7b3d2f6e08ed # x86/tsc: Use X86_FEATURE_TSC_ADJUST in detect_art()
> > git cherry-pick -x bec8520dca0d # x86/tsc: Detect random warps
> > git cherry-pick -x 8b223bc7abe0 # x86/tsc: Store and check TSC ADJUST MSR
> > git cherry-pick -x 1d0095feea59 # x86/tsc: Verify TSC_ADJUST from idle
> > git cherry-pick -x a36f5136814b # x86/tsc: Sync test only for the first cpu in a package
> > git cherry-pick -x 4c5e3c637521 # x86/tsc: Move sync cleanup to a safe place
> > git cherry-pick -x 76d3b8515850 # x86/tsc: Prepare warp test for TSC adjustment
> > git cherry-pick -x cc4db26899dc # x86/tsc: Try to adjust TSC if sync test fails
> > git cherry-pick -x b836554386cc # x86/tsc: Fix broken CONFIG_X86_TSC=n build
> > git cherry-pick -x 31f8a651fc57 # x86/tsc: Validate cpumask pointer before accessing it
> > git cherry-pick -x 6a369583178d # x86/tsc: Validate TSC_ADJUST after resume
> > git cherry-pick -x 5bae156241e0 # x86/tsc: Force TSC_ADJUST register to value >= zero
> > git cherry-pick -x 16588f659257 # x86/tsc: Annotate printouts as firmware bug
> > git cherry-pick -x 8c9b9d87b855 # x86/tsc: Limit the adjust value further
> > 
> > There's a conflict only in a one small place in the first few patches.
> 
> That's a lot of changes to be backported.  I'm _really_ hesitant to do
> this, unless the maintainer of the code agrees it is ok...

Those TSC_ADJUST fixes are just an initial workaround. Peter has updated
that since then to the final and proper solution, which makes it dependend
on micro code version checks. If at all then the whole lot wants to be
backported, which is way more than the above set.

Thanks,

	tglx