user/sven/linux.git/arch/s390/kernel/processor.c, branch v5.7

s390/cpuinfo: do not skip info for CPUs without MHz feature

2020-03-23T12:41:55Z

In the past there were no per-CPU information in /proc/cpuinfo other than CPU frequency. Hence, for machines without CPU MHz feature there were nothing to show. Now CPU topology and IDs still could be shown, so do not skip this information from the output. Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens [heiko.carstens@de.ibm.com: moved comparison] Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/cpuinfo: fix wrong output when CPU0 is offline

2020-03-23T12:41:54Z

/proc/cpuinfo should not print information about CPU 0 when it is offline. Fixes: 281eaa8cb67c ("s390/cpuinfo: simplify locking and skip offline cpus early") Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens [heiko.carstens@de.ibm.com: shortened commit message] Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/cpuinfo: show number of online CPUs within a package

2020-03-23T12:41:54Z

Show number of online CPUs within a package (which is the socket in case of s390). For what it worth, present that value as "siblings" field - just like x86 does. Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/cpuinfo: show number of online cores

2020-03-23T12:41:54Z

Show number of cores that run at least one SMT thread Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/cpuinfo: show processor physical address

2020-03-23T12:41:53Z

Show CPU physical address as reported by STAP instruction Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/cpuinfo: add system topology information

2020-03-10T14:16:26Z

This update adjusts /proc/cpuinfo format to meet some user level programs expectations. It also makes the layout consistent with x86 where CPU topology is presented as blocks of key-value pairs. Reviewed-by: Vasily Gorbik Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik

processor: get rid of cpu_relax_yield

2019-06-15T10:25:55Z

stop_machine is the only user left of cpu_relax_yield. Given that it now has special semantics which are tied to stop_machine introduce a weak stop_machine_yield function which architectures can override, and get rid of the generic cpu_relax_yield implementation. Acked-by: Peter Zijlstra (Intel) Acked-by: Thomas Gleixner Signed-off-by: Heiko Carstens

s390: improve wait logic of stop_machine

2019-06-15T10:25:52Z

The stop_machine loop to advance the state machine and to wait for all affected CPUs to check-in calls cpu_relax_yield in a tight loop until the last missing CPUs acknowledged the state transition. On a virtual system where not all logical CPUs are backed by real CPUs all the time it can take a while for all CPUs to check-in. With the current definition of cpu_relax_yield a diagnose 0x44 is done which tells the hypervisor to schedule *some* other CPU. That can be any CPU and not necessarily one of the CPUs that need to run in order to advance the state machine. This can lead to a pretty bad diagnose 0x44 storm until the last missing CPU finally checked-in. Replace the undirected cpu_relax_yield based on diagnose 0x44 with a directed yield. Each CPU in the wait loop will pick up the next CPU in the cpumask of stop_machine. The diagnose 0x9c is used to tell the hypervisor to run this next CPU instead of the current one. If there is only a limited number of real CPUs backing the virtual CPUs we end up with the real CPUs passed around in a round-robin fashion. [heiko.carstens@de.ibm.com]: Use cpumask_next_wrap as suggested by Peter Zijlstra. Signed-off-by: Martin Schwidefsky Acked-by: Peter Zijlstra (Intel) Acked-by: Thomas Gleixner Signed-off-by: Heiko Carstens

s390: report new CPU capabilities

2019-04-25T13:34:10Z

Add hardware capability bits and features tags to /proc/cpuinfo for 4 new CPU features: "Vector-Enhancements Facility 2" (tag "vxe2", hwcap 2^15) "Vector-Packed-Decimal-Enhancement Facility" (tag "vxp", hwcap 2^16) "Enhanced-Sort Facility" (tag "sort", hwcap 2^17) "Deflate-Conversion Facility" (tag "dflt", hwcap 2^18) Reviewed-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: run user space and KVM guests with modified branch prediction

2018-02-05T13:48:50Z

Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary plumbing in entry.S to be able to run user space and KVM guests with limited branch prediction. To switch a user space process to limited branch prediction the s390_isolate_bp() function has to be call, and to run a vCPU of a KVM guest associated with the current task with limited branch prediction call s390_isolate_bp_guest(). Signed-off-by: Martin Schwidefsky