kernel.git/arch/s390/kernel/smp.c, branch linux-3.7.y

s390: add uninitialized_var() to suppress false positive compiler warnings

2012-09-26T13:45:23Z

Get rid of these: arch/s390/kernel/smp.c:134:19: warning: ‘status’ may be used uninitialized in this function [-Wuninitialized] arch/s390/mm/pgtable.c:641:10: warning: ‘table’ may be used uninitialized in this function [-Wuninitialized] arch/s390/mm/pgtable.c:644:12: warning: ‘page’ may be used uninitialized in this function [-Wuninitialized] drivers/s390/cio/cio.c:1037:14: warning: ‘schid’ may be used uninitialized in this function [-Wuninitialized] Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/smp,topology: add polarization member to pcpu struct

2012-09-26T13:45:09Z

The cpu polarization member is the only per cpu state that is not part of the pcpu structure. So add it there and have everything in one place. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/smp: avoid concurrent write to sigp status field

2012-09-26T13:45:04Z

When a sigp instruction is issued it may store a status. This status is currently stored in a per cpu field of the target cpu. If multiple cpus issue a sigp instruction with the same target cpu and a status is stored the result is not necessarily as expected. Currently this is not an issue: - on cpu hotplug no sigps, except "restart" and "sense" are sent to the target cpu. - on external call we don't look at the status if it is stored - on sense running the condition code "status stored" is sufficient to tell if a cpu is running or not Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/cpu hotplug: mask out CPU_TASKS_FROZEN in cu hotplug notifiers

2012-09-26T13:44:53Z

Unify all our cpu hotplug notifiers to mask out the CPU_TASKS_FROZEN bit, so we don't have to add all the *_FROZEN variant cases to the notifiers. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/cpu hotplug: use hotcpu_notifier() instead of register_cpu_notifier()

2012-09-26T13:44:52Z

Saves a couple of lines of code. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2012-07-24T16:49:09Z

Pull s390 changes from Martin Schwidefsky: "No new functions, a few changes to make the code more robust, some cleanups and bug fixes." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (21 commits) s390/vtimer: rework virtual timer interface s390/dis: Add the servc instruction to the disassembler. s390/comments: unify copyright messages and remove file names s390/lgr: Add init check to lgr_info_log() s390/cpu init: use __get_cpu_var instead of per_cpu s390/idle: reduce size of s390_idle_data structure s390/idle: fix sequence handling vs cpu hotplug s390/ap: resend enable adapter interrupt request. s390/hypfs: Add missing get_next_ino() s390/dasd: add shutdown action s390/ipl: Fix ipib handling for "dumpreipl" shutdown action s390/smp: make absolute lowcore / cpu restart parameter accesses more robust s390/vmlogrdr: cleanup driver attribute usage s390/vmlogrdr: cleanup device attribute usage s390/ccwgroup: remove unused ccwgroup_device member s390/cio/chp: cleanup attribute usage s390/sigp: use sigp order code defines in assembly code s390/smp: use sigp cpu status definitions s390/smp/kvm: unifiy sigp definitions s390/smp: remove redundant check ...

s390/vtimer: rework virtual timer interface

2012-07-20T09:15:08Z

The current virtual timer interface is inherently per-cpu and hard to use. The sole user of the interface is appldata which uses it to execute a function after a specific amount of cputime has been used over all cpus. Rework the virtual timer interface to hook into the cputime accounting. This makes the interface independent from the CPU timer interrupts, and makes the virtual timers global as opposed to per-cpu. Overall the code is greatly simplified. The downside is that the accuracy is not as good as the original implementation, but it is still good enough for appldata. Reviewed-by: Jan Glauber Reviewed-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/comments: unify copyright messages and remove file names

2012-07-20T09:15:04Z

Remove the file name from the comment at top of many files. In most cases the file name was wrong anyway, so it's rather pointless. Also unify the IBM copyright statement. We did have a lot of sightly different statements and wanted to change them one after another whenever a file gets touched. However that never happened. Instead people start to take the old/"wrong" statements to use as a template for new files. So unify all of them in one go. Signed-off-by: Heiko Carstens

s390/idle: fix sequence handling vs cpu hotplug

2012-07-17T08:34:27Z

The s390 idle accounting code uses a sequence counter which gets used when the per cpu idle statistics get updated and read. One assumption on read access is that only when the sequence counter is even and did not change while reading all values the result is valid. On cpu hotplug however the per cpu data structure gets initialized via a cpu hotplug notifier on CPU_ONLINE. CPU_ONLINE however is too late, since the onlined cpu is already running and might access the per cpu data. Worst case is that the data structure gets initialized while an idle thread is updating its idle statistics. This will result in an uneven sequence counter after an update. As a result user space tools like top, which access /proc/stat in order to get idle stats, will busy loop waiting for the sequence counter to become even again, which will never happen until the queried cpu will update its idle statistics again. And even then the sequence counter will only have an even value for a couple of cpu cycles. Fix this by moving the initialization of the per cpu idle statistics to cpu_init(). I prefer that solution in favor of changing the notifier to CPU_UP_PREPARE, which would be a different solution to the problem. Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/smp: make absolute lowcore / cpu restart parameter accesses more robust

2012-06-14T07:09:02Z

Setting the cpu restart parameters is done in three different fashions: - directly setting the four parameters individually - copying the four parameters with memcpy (using 4 * sizeof(long)) - copying the four parameters using a private structure In addition code in entry*.S relies on a certain order of the restart members of struct _lowcore. Make all of this more robust to future changes by adding a mem_absolute_assign(dest, val) define, which assigns val to dest using absolute addressing mode. Also the load multiple instructions in entry*.S have been split into separate load instruction so the order of the struct _lowcore members doesn't matter anymore. In addition move the prototypes of memcpy_real/absolute from uaccess.h to processor.h. These memcpy* variants are not related to uaccess at all. string.h doesn't seem to match as well, so lets use processor.h. Also replace the eight byte array in struct _lowcore which represents a misaliged u64 with a u64. The compiler will always create code that handles the misaligned u64 correctly. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky