s390: remove unused MACHINE_FLAG_RRBM

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Documentation/kprobes: add s390 to list of supported architectures

s390 supports kprobes since 2006 but is missing in the list of
architectures that support kprobes.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/vdso: replace stck with stcke

If gettimeofday / clock_gettime are called multiple times in a row
the STCK instruction will stall until a difference in the result is
visible. This unnecessarily slows down the vdso calls, use stcke
instead of stck to get rid of the stall.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/vdso: add vdso support for coarse clocks

Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to
the 64-bit and 31-bit vdso.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390: pass march flag to assembly files as well

Currently the march flag gets only passed to C files, but not to
assembler files.
This means that we can't add new instructions like e.g. aghik to asm
files, since the assembler doesn't know of the new instructions if
the appropriate march flag isn't specified.

So also pass the march flag when compiling assembler files as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/ftrace: optimize function graph caller code

When the function graph tracer is disabled we can skip three additional
instructions. So let's just do this.

So if function tracing is enabled but function graph tracing is
runtime disabled, we get away with a single unconditional branch.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/ftrace: add HAVE_DYNAMIC_FTRACE_WITH_REGS support

This code is based on a patch from Vojtech Pavlik.
http://marc.info/?l=linux-s390&m=140438885114413&w=2

The actual implementation now differs significantly:
Instead of adding a second function "ftrace_regs_caller" which would be nearly
identical to the existing ftrace_caller function, the current ftrace_caller
function is now an alias to ftrace_regs_caller and always passes the needed
pt_regs structure and function_trace_op parameters unconditionally.

Besides that also use asm offsets to correctly allocate and access the new
struct pt_regs on the stack.

While at it we can make use of new instruction to get rid of some indirect
loads if compiled for new machines.

The passed struct pt_regs can be changed by the called function and it's new
contents will replace the current contents.

Note: to change the return address the embedded psw member of the pt_regs
structure must be changed. The psw member is right now incomplete, since
the mask part is missing. For all current use cases this should be sufficent.
Providing and restoring a sane mask would mean we need to add an epsw/lpswe
pair to the mcount code. Only these two instruction would cost us ~120 cycles
which currently seems not necessary.

Cc: Vojtech Pavlik <vojtech@suse.cz>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/ftrace: enforce DYNAMIC_FTRACE if FUNCTION_TRACER is selected

We have too many combinations for function tracing. Lets simply stick to
the most advanced option, so we don't have to care of other combinations.

This means we always select DYNAMIC_FTRACE if FUNCTION_TRACER is selected.

In the s390 Makefile also remove CONFIG_FTRACE_SYSCALLS since that
functionality got moved to architecture independent code in the meantime.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/kprobes: remove unused jprobe_return_end()

Even if it has a __used annotation it is actually unused.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/ftrace: optimize mcount code

Reduce the number of executed instructions within the mcount block if
function tracing is enabled. We achieve that by using a non-standard
C function call ABI. Since the called function is also written in
assembler this is not a problem.
This also allows to replace the unconditional store at the beginning
of the mcount block with a larl instruction, which doesn't touch
memory.

In theory we could also patch the first instruction of the mcount block
to enable and disable function tracing. However this would break kprobes.
This could be fixed with implementing the "kprobes_on_ftrace" feature;
however keeping the odd jprobes working seems not to be possible without
a lot of code churn. Therefore keep the code easy and simply accept one
wasted 1-cycle "larl" instruction per function prologue.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/spinlock: optimize spin_unlock code

Use a memory barrier + store sequence instead of a load + compare and swap
sequence to unlock a spinlock and an rw lock.
For the spinlock case this saves us two memory reads and a not needed cpu
serialization after the compare and swap instruction stored the new value.

The kernel size (performance_defconfig) gets reduced by ~14k.

Average execution time of a tight inlined spin_unlock loop drops from
5.8ns to 0.7ns on a zEC12 machine.

An artificial stress test case where several counters are protected with
a single spinlock and which are only incremented while holding the spinlock
shows ~30% improvement on a 4 cpu machine.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/zcrypt: support for extended number of ap domains

Extends the number of ap domains within the zcrypt device driver up to 256.
AP domains in the range 00..255 will be detected.

Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/sclp: reduce dependency on event type masks

The event type masks can change asynchronously. These changes are reported
by SCLP to the OS by state-change events which are retrieved with the read
event data command. The SCLP driver has a request queue, there is a window
where the read event data request has not completed yet but the SCLP console
drivers are trying to queue output requests. As the masks are not updated
yet the requests are discarded.

The simplest fix is to queue the console requests independent of the
event type masks and rely on SCLP to return with an error code if a
specific event type is not available.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/hmcdrv: HMC drive CD/DVD access

This device driver allows accessing a HMC drive CD/DVD-ROM.
It can be used in a LPAR and z/VM environment.

Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ralf Hoppe <rhoppe@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/tape: fix MTIOCGET ioctl to report blocksize

Remove tape_state from status register and report the drive's current
setting for block size instead as known from other tapes.
Density is not supported so nothing to report here.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/zcrypt: Fixed possible race condition in zcrypt module handling

Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/rwlock: use directed yield for write-locked rwlocks

Add an owner field to the arch_rwlock_t to be able to pass the timeslice
of a virtual CPU with diagnose 0x9c to the lock owner in case the rwlock
is write-locked. The undirected yield in case the rwlock is acquired
writable but the lock is read-locked is removed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/head.s: use zero as address for stfl

The architecture suggests to use address 0 as parameter for stfl,
to allow for future extensions. Using __LC_STFL_FAC_LIST (0x200)
shows which address is used, but might be not future proof.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/vmemmap: remove memset call from vmemmap_populate()

If the vmemmap array gets filled with large pages we allocate those
pages with vmemmap_alloc_block(), which returns cleared pages.
Only for single 4k pages we call our own vmem_alloc_pages() which does
not return cleared pages. However we can also call vmemmap_alloc_block()
to allocate the 4k pages.
This way we can also make sure the vmemmap array is cleared after its
population.
Therefore we can remove the memset at the end of the function which
would clear the vmmemmap array a second time on machines which do
support EDAT1.

On very large configurations this can save us several seconds.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
s390/mm: remove change bit override support

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>