Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
"This is the last functional update from the tip tree for 4.10. It got
delayed due to a newly reported and anlyzed variant of BIOS bug and
the resulting wreckage:
- Seperation of TSC being marked realiable and the fact that the
platform provides the TSC frequency via CPUID/MSRs and making use
for it for GOLDMONT.
- TSC adjust MSR validation and sanitizing:
The TSC adjust MSR contains the offset to the hardware counter. The
sum of the adjust MSR and the counter is the TSC value which is
read via RDTSC.
On at least two machines from different vendors the BIOS sets the
TSC adjust MSR to negative values. This happens on cold and warm
boot. While on cold boot the offset is a few milliseconds, on warm
boot it basically compensates the power on time of the system. The
BIOSes are not even using the adjust MSR to set all CPUs in the
package to the same offset. The offsets are different which renders
the TSC unusable,
What's worse is that the TSC deadline timer has a HW feature^Wbug.
It malfunctions when the TSC adjust value is negative or greater
equal 0x80000000 resulting in silent boot failures, hard lockups or
non firing timers. This looks like some hardware internal 32/64bit
issue with a sign extension problem. Intel has been silent so far
on the issue.
The update contains sanity checks and keeps the adjust register
within working limits and in sync on the package.
As it looks like this disease is spreading via BIOS crapware, we
need to address this urgently as the boot failures are hard to
debug for users"
* 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tsc: Limit the adjust value further
x86/tsc: Annotate printouts as firmware bug
x86/tsc: Force TSC_ADJUST register to value >= zero
x86/tsc: Validate TSC_ADJUST after resume
x86/tsc: Validate cpumask pointer before accessing it
x86/tsc: Fix broken CONFIG_X86_TSC=n build
x86/tsc: Try to adjust TSC if sync test fails
x86/tsc: Prepare warp test for TSC adjustment
x86/tsc: Move sync cleanup to a safe place
x86/tsc: Sync test only for the first cpu in a package
x86/tsc: Verify TSC_ADJUST from idle
x86/tsc: Store and check TSC ADJUST MSR
x86/tsc: Detect random warps
x86/tsc: Use X86_FEATURE_TSC_ADJUST in detect_art()
x86/tsc: Finalize the split of the TSC_RELIABLE flag
x86/tsc: Set TSC_KNOWN_FREQ and TSC_RELIABLE flags on Intel Atom SoCs
x86/tsc: Mark Intel ATOM_GOLDMONT TSC reliable
x86/tsc: Mark TSC frequency determined by CPUID as known
x86/tsc: Add X86_FEATURE_TSC_KNOWN_FREQ flag
