linux-toradex.git/arch/s390/include/asm/lowcore.h, branch v3.0.74

[S390] pfault: cpu hotplug vs missing completion interrupts

2011-05-23T08:24:29+00:00

On cpu hot remove a PFAULT CANCEL command is sent to the hypervisor
which in turn will cancel all outstanding pfault requests that have
been issued on that cpu (the same happens with a SIGP cpu reset).

The result is that we end up with uninterruptible processes where
the interrupt that would wake up these processes never arrives.

In order to solve this all processes which wait for a pfault
completion interrupt get woken up after a cpu hot remove. The worst
case that could happen is that they fault again and in turn need to
wait again.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] Remove data execution protection

2011-05-23T08:24:28+00:00

The noexec support on s390 does not rely on a bit in the page table
entry but utilizes the secondary space mode to distinguish between
memory accesses for instructions vs. data. The noexec code relies
on the assumption that the cpu will always use the secondary space
page table for data accesses while it is running in the secondary
space mode. Up to the z9-109 class machines this has been the case.
Unfortunately this is not true anymore with z10 and later machines.
The load-relative-long instructions lrl, lgrl and lgfrl access the
memory operand using the same addressing-space mode that has been
used to fetch the instruction.
This breaks the noexec mode for all user space binaries compiled
with march=z10 or later. The only option is to remove the current
noexec support.

Signed-off-by: Martin Schwidefsky

[S390] cleanup facility list handling

2010-10-25T14:10:21+00:00

Store the facility list once at system startup with stfl/stfle and
reuse the result for all facility tests.

Signed-off-by: Martin Schwidefsky

[S390] virtualization aware cpu measurement

2010-05-17T08:00:15+00:00

Use the SPP instruction to set a tag on entry to / exit of the virtual
machine context. This allows the cpu measurement facility to distinguish
the samples from the host and the different guests.

Signed-off-by: Carsten Otte

[S390] idle time accounting vs. machine checks

2010-05-17T08:00:15+00:00

A machine check can interrupt the i/o and external interrupt handler
anytime. If the machine check occurs while the interrupt handler is
waking up from idle vtime_start_cpu can get executed a second time
and the int_clock / async_enter_timer values in the lowcore get
clobbered. This can confuse the cpu time accounting.
To fix this problem two changes are needed. First the machine check
handler has to use its own copies of int_clock and async_enter_timer,
named mcck_clock and mcck_enter_timer. Second the nested execution
of vtime_start_cpu has to be prevented. This is done in s390_idle_check
by checking the wait bit in the program status word.

Signed-off-by: Martin Schwidefsky

[S390] More cleanup for struct _lowcore

2010-05-17T08:00:15+00:00

Remove cpu_id from lowcore and replace addr_t with __u64.

Signed-off-by: Martin Schwidefsky

[S390] Cleanup struct _lowcore usage and defines.

2010-02-26T21:37:31+00:00

Use asm offsets to make sure the offset defines to struct _lowcore and
its layout don't get out of sync.
Also add a BUILD_BUG_ON() which checks that the size of the structure
is sane.
And while being at it change those sites which use odd casts to access
the current lowcore. These should use S390_lowcore instead.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] smp: rename and add lowcore defines

2010-02-26T21:37:30+00:00

Rename __LC_RESTART_PSW to __LC_RST_NEW_PSW, add a define for the
missing 32 bit variant and the missing old PSWs.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] zfcpdump: remove cross arch dump support

2010-02-26T21:37:30+00:00

Remove support to be able to dump 31 bit systems with a 64 bit dumper.
This is mostly useless since no distro ships 31 bit kernels together
with a 64 bit dumper.
We also get rid of a bit of hacky code.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

[S390] Fix struct _lowcore layout.

2010-02-09T08:46:23+00:00

Offsets and sizes are wrong for 32 bit.
Got broken with 866ba284 "[S390] cleanup lowcore.h".

Reported-by: Mahesh Salgaonkar 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky