linux/arch/s390/kernel, branch v3.8.10

s390: critical section cleanup vs. machine checks

2013-03-20T20:10:56Z

commit 6551fbdfd8b85d1ab5822ac98abb4fb449bcfae0 upstream. The current machine check code uses the registers stored by the machine in the lowcore at __LC_GPREGS_SAVE_AREA as the registers of the interrupted context. The registers 0-7 of a user process can get clobbered if a machine checks interrupts the execution of a critical section in entry[64].S. The reason is that the critical section cleanup code may need to modify the PSW and the registers for the previous context to get to the end of a critical section. If registers 0-7 have to be replaced the relevant copy will be in the registers, which invalidates the copy in the lowcore. The machine check handler needs to explicitly store registers 0-7 to the stack. Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390/timer: avoid overflow when programming clock comparator

2013-01-31T13:01:52Z

Since ed4f209 "s390/time: fix sched_clock() overflow" a new helper function is used to avoid overflows when converting TOD format values to nanosecond values. The kvm interrupt code formerly however only worked by accident because of an overflow. It tried to program a timer that would expire in more than ~29 years. Because of the old TOD-to-nanoseconds overflow bug the real expiry value however was much smaller, but now it isn't anymore. This however triggers yet another bug in the function that programs the clock comparator s390_next_ktime(): if the absolute "expires" value is after 2042 this will result in an overflow and the programmed value is lower than the current TOD value which immediatly triggers a clock comparator (= timer) interrupt. Since the timer isn't expired it will be programmed immediately again and so on... the result is a dead system. To fix this simply program the maximum possible value if an overflow is detected. Reported-by: Christian Borntraeger Tested-by: Christian Borntraeger Cc: stable@vger.kernel.org # v3.3+ Signed-off-by: Heiko Carstens

s390/time: fix sched_clock() overflow

2013-01-16T14:57:52Z

Converting a 64 Bit TOD format value to nanoseconds means that the value must be divided by 4.096. In order to achieve that we multiply with 125 and divide by 512. When used within sched_clock() this triggers an overflow after appr. 417 days. Resulting in a sched_clock() return value that is much smaller than previously and therefore may cause all sort of weird things in subsystems that rely on a monotonic sched_clock() behaviour. To fix this implement a tod_to_ns() helper function which converts TOD values without overflow and call this function from both places that open coded the conversion: sched_clock() and kvm_s390_handle_wait(). Cc: stable@kernel.org Reviewed-by: Martin Schwidefsky Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/topology: export cpu_topology

2013-01-08T09:57:10Z

Export cpu_topology symbol, so it's available for modules. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/pm: export pm_power_off

2013-01-08T09:57:09Z

Export pm_power_off symbol. Needed by at least one of the new device drivers that come with CONFIG_PCI. And all other architectures export that symbol as well. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/irq: count cpu restart events

2013-01-08T09:57:07Z

Count CPU Restart events and make them visible via /proc/interrupts. Every CPU hotplug (online) event will increase the per cpu counter. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/irq: remove split irq fields from /proc/stat

2013-01-08T09:57:07Z

Now that irq sum accounting for /proc/stat's "intr" line works again we have the oddity that the sum field (first field) contains only the sum of the second (external irqs) and third field (I/O interrupts). The reason for that is that these two fields are already sums of all other fields. So if we would sum up everything we would count every interrupt twice. This is broken since the split interrupt accounting was merged two years ago: 052ff461c8427629aee887ccc27478fc7373237c "[S390] irq: have detailed statistics for interrupt types". To fix this remove the split interrupt fields from /proc/stat's "intr" line again and only have them in /proc/interrupts. This restores the old behaviour, seems to be the only sane fix and mimics a behaviour from other architectures where /proc/interrupts also contains more than /proc/stat's "intr" line does. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/irq: enable irq sum accounting for /proc/stat again

2013-01-08T09:57:06Z

For more than two years, since f2c66cd8eeddedb440f33bc0f5cec1ed7ae376cb "/proc/stat: scalability of irq num per cpu" the output of /proc/stat is broken. The first field in the "intr" line should contain the sum of all interrupts, however since the above mentioned change it is always zero. The reason for that is that a per cpu irq sum variable had been introduced which got incremented when calling kstat_incr_irqs_this_cpu(). However on s390 we directly incremented only the per cpu per irq counter by accessing the array element via kstat_cpu(smp_processor_id()).irqs[...]. So fix this and use the kstat_incr_irqs_this_cpu() wrapper which increments both: the per cpu per irq counter and the per cpu irq sum counter. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/syscalls: wire up finit_module syscall

2013-01-08T09:57:05Z

Signed-off-by: Heiko Carstens

s390/smp: fix section mismatch for smp_add_present_cpu()

2013-01-08T09:57:04Z

Fixes this section mismatch: WARNING: vmlinux.o(.text+0x145e4): Section mismatch in reference from the function smp_add_present_cpu() to the function .cpuinit.text:register_cpu() The function smp_add_present_cpu() references the function __cpuinit register_cpu(). This is often because smp_add_present_cpu lacks a __cpuinit annotation or the annotation of register_cpu is wrong. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky