Depending on the gcc version we can use builtin_bswap instead of
architecture functions. Doing so is better than the inline assembly
version of load reverse for two reasons:
- the sequence of load reversed, apply constant mask, save reversed can
  be optimized to load, apply reversed mask, save
- builtins are slightly better to optimize e.g. gcc instruction
  scheduler cannot optimize grouping on inline assemblies.

To enable set we have to ARCH_USE_BUILTIN_BSWAP.
bloat-o-meter results:
add/remove: 1/1 grow/shrink: 75/533 up/down: 1711/-9394 (-7683)
Suggested-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Path verification is either done via dasd_eckd_read_conf() which is
triggered during online processing and resume or via
do_path_verification_work() which is triggered after path events.
The dasd_eckd_read_conf() version added paths unconditionally and did
not check if the path mask was empty. This led to devices having the
disconnected stop flag set but a valid path mask. So they where not
working although they had paths validated successfully. After a resume
this state could even not be solved with additional paths added.

Fix by checking for an empty path mask in dasd_eckd_read_conf() and
clearing the device stop bits for a newly added channel path.
Reviewed-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

For a valid PAV assignment the DASD driver needs to notice possibly
changed configuration data. Thus the failing of read configuration
data should also fail the device restore to prevent invalid PAV
assignment. The failed device may get restored after additional paths
get available later on.
If the restore fails after the device was added to the lcu alias
handling it needs to be removed from the alias handling before exiting
the restore function.
Reviewed-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The configuration data is stored per path and also the first valid
configuration data per device. When dasd_eckd_read_conf is called
again after a path got lost the device configuration data is cleared
but possibly not the per path configuration data. This might lead to a
double free when the lost path gets operational again.

Fix by clearing all per path configuration data when the first valid
configuration data is received and stored.
Reviewed-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

git commit 155e839a
"s390/kernel: dynamically allocate FP register save area"
introduced a regression in regard to ptrace.

If the vector register extension is not present or unused the
ptrace peek of a floating pointer register return incorrect data
and the ptrace poke to a floating pointer register overwrites the
task structure starting at task->thread.fpu.fprs.

Cc: stable@kernel.org # v4.3
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

device_ops.c should only contain functions that are called by ccw device
drivers. Move the cio internal functions that handle unconditional
reserve + release to device_pgid.c
Acked-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

device_ops.c should only contain functions that are called by ccw device
drivers. Move the cio internal function ccw_device_call_handler to
device_fsm.c where it's used. Remove some useless comments while at it.
Acked-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Each per_cpu() invocation generates extra code. Since there are a lot
of similiar calls in the topology code we can avoid a lot of them.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Change the flag fields within struct mcck_struct to simple bit fields
to reduce the size of the structure which is used as percpu variable.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

According to the architecture registers are validated and not
revalidated. So change comments and functions names to match.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove all the casts to and from the machine check interruption code.
This patch changes struct mci to a union, which contains an anonymous
structure with the already known bits and in addition an unsigned
long field, which contains the raw machine check interruption code.

This allows to simply assign and decoce the interruption code value
without the need for all those casts we had all the time.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

s390_handle_damage() has character string parameter which was used as
a pointer to verbose error message. The hope was (a lot of years ago)
when analyzing dumps that register R2 would still contain the pointer
and therefore it would be rather easy to tell what went wrong.

However gcc optimizes the strings away since a long time. And even if
it wouldn't it is necessary to have a close look at the machine check
interruption code to tell what's wrong.

So remove the pointless error strings.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The current disabled wait code stores register contents into their
save areas, however it is (at least) missing the new vector registers.

Given the fact that the whole exercise seems to be rather pointless
simply don't save any registers anymore.

In a "live" system it is always possible to inspect register contents,
and in case of a dump the register contents will be stored by the
dump mechanism.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

With the removal of 31 bit code we can always assume that the epsw
instruction is available. Therefore use the __extract_psw() function
to disable and enable machine checks.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Split the API and FPU type definitions into separate header files
similar to "x86/fpu: Rename fpu-internal.h to fpu/internal.h" (78f7f1e5).

The new header files and their meaning are:

asm/fpu/types.h:
	FPU related data types, needed for 'struct thread_struct' and
	'struct task_struct'.

asm/fpu/api.h:
	FPU related 'public' functions for other subsystems and device
	drivers.

asm/fpu/internal.h:
	FPU internal functions mainly used to convert
	FPU register contents in signal handling.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

A summary unit check occurs when the lcu updates the PAV configuration
e.g. base PAV assignment or PAV mode at all. This requires the reset
of the drivers internal pavgroups. Therefore the alias devices are
flushed and moved via a temporary list to the active_devices list
where they are not associated with a pavgroup. In conjunction with
updates to the base device the pavgroup may be removed since both
base_list and alias_list are empty. Unfortunately during alias flush
and move to the active_device list from alias_list the pavgroup
pointer is not deleted in the device private structure. This leads to
a list del_corruption if another lcu_update tries to move the device
in the non existent pavgroup.

Fix by removing the pavgroup pointer after the alias device was moved
to the active_devices list.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

the kernel locks have aqcuire/release semantics. No operation done
after the lock can be "moved" before the lock and no operation before
the unlock can be moved after the unlock. But it is perfectly fine
that memory accesses which happen code wise after unlock are performed
within the critical section.
On s390x, reads are in-order with other reads (PoP section
"Storage-Operand Fetch References") and writes are in-order with
other writes (PoP section "Storage-Operand Store References"). Writes
are also in-order with reads to the same memory location (PoP section
"Storage-Operand Store References"). To other CPUs (and the channel
subsystem), reads additionally appear to be performed prior to reads or
writes that happen after them in the conceptual sequence (PoP section
"Relation between Operand Accesses").
So at least as observed by other CPUs and the channel subsystem, reads
inside the critical sections will not happen after unlock (and writes
are in-order anyway). That's exactly what we need for "RELEASE
operations" (memory-barriers.txt): "It guarantees that all memory
operations before the RELEASE operation will appear to happen before the
RELEASE operation with respect to the other components of the system."
Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-By: NSascha Silbe <silbe@linux.vnet.ibm.com>
[cross-reading and lot of improvements for the patch description]
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

There is a system work queue system_long_wq for long running work.
Use this work queue for the AP bus scan loop.
Reviewd-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the code for really old crypt cards, PCICC and PCICA.
These cards have been out of service for several years.
Reviewd-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Replace the two fields 'unregistered' and 'reset' with a device
state with 5 possible values. Introduce two events for the AP devices,
device poll and device timeout. With the state machine it is easier
to deal with device initialization and suspend/resume. Device polling
is simpler as well, the arkane 'flags' passing is gone.
Reviewd-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

If a AP device is removed while messages are still pending, the requests
are cancelled by calling the message receive function with an error pointer
for the reply. The message type receive handler recognize this and create
a fake hardware error TYPE82_RSP_CODE / REP82_ERROR_MACHINE_FAILURE.
The message with the hardware error then causes a printk and a return
code of -EAGAIN.

Replace the intricate scheme with an explicit return code for this sitation
and avoid the error message.
Reviewd-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Set the configuration timer at the end of the ap_scan_bus function.
Make use of setup_timer and remove some unnecessary add_timer, mod_timer
and del_timer_sync calls. Replace the complicated timer_pending, mod_timer
and add_timer code in ap_config_time_store with a simple mod_timer.
Reviewd-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

If there are no devices on the AP bus there will not be a single
call to the per-device ap_bus_suspend function. Even worse,
there will not be a call to the per-device ap_bus_resume either
and the AP will fail so resume correctly.

Introduce a bus specific dev_pm_ops to suspend / resume the AP
bus related things. While we are at it, simplify the power management
code of the AP bus.
Reviewd-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The ap_queue_messsage function will call device_unregister if the
unregistered field of the device has been set while trying to queue
a message. This races with other device_unregister calls, e.g. from
the ap_scan_bus. Remove the call to device_unregister from
ap_queue_message and let ap_scan_bus deal with it.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The ap_query_configuration function allocates the ap_config_info
structure, but there is no code to free the structure.
Allocate the structure in the module_init function and free it
again in module_exit.

While we are at it simplify a few functions in regard to the
ap configuration data.
Reviewed-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

ap_test_queue, ap_query_facilities, __ap_query_functions all use
the same PQAP(TAPQ) command. Consolidate the three into a single
ap_test_queue function that returns the AP status and the 64-bit
result. The exception table entry for PQAP(TAPQ) can be avoided
if the T bit for the APFT facility is set only if test_facility(15)
indicated that the facility is present.

Integrate ap_query_function into ap_query queue to avoid calling
PQAP(TAPQ) twice.
Reviewed-by: NIngo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The first level machine check handler for etr and stp machine checks may
call queue_work() while in nmi context. This may deadlock e.g. if the
machine check happened when the interrupted context did hold a lock, that
also will be acquired by queue_work().
Therefore split etr and stp machine check handling into first and second
level handling. The second level handling will then issue the queue_work()
call in process context which avoids the potential deadlock.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

zpci_err_insn writes stale stack content to the debugfs.

Ensure that the struct in zpci_err_insn is ordered in a way that
we don't have uninitialized holes in it. In addition to that
add the packed attribute.

Fixes: 3d8258e4 (s390/pci: move debug messages to debugfs)
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

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

With the removal of 31 bit support a couple of defines became unused.
Remove them.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

For some unknown reason the mcck_interruption_code field is defined
as array of two 32 bit values. Given that this actually is a 64 bit
field according to the architecture, change the type to u64.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The defines that are used in entry.S have been partially converted to
use the _BITUL macro (setup.h). This patch converts the rest.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The cpu flags and pt_regs flags fields are each 64 bits in size. A flag can
be set with helper functions like set_cpu_flags().

These functions create a mask using "1U << flag". This doesn't work if flag
is larger than 31, since 1U << 32 == 0.

So fix this in case we ever will have such flag numbers.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

When using systemtap it was observed that our udelay implementation is
rather suboptimal if being called from a kprobe handler installed by
systemtap.

The problem observed when a kprobe was installed on lock_acquired().
When the probe was hit the kprobe handler did call udelay, which set
up an (internal) timer and reenabled interrupts (only the clock comparator
interrupt) and waited for the interrupt.
This is an optimization to avoid that the cpu is busy looping while waiting
that enough time passes. The problem is that the interrupt handler still
does call irq_enter()/irq_exit() which then again can lead to a deadlock,
since some accounting functions may take locks as well.

If one of these locks is the same, which caused lock_acquired() to be
called, we have a nice deadlock.

This patch reworks the udelay code for the interrupts disabled case to
immediately leave the low level interrupt handler when the clock
comparator interrupt happens. That way no C code is being called and the
deadlock cannot happen anymore.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

sparse does not understand the s390 specific hotpatch attribute and
floods the log with messages like
include/uapi/linux/swab.h:92:8: error: attribute 'hotpatch': unknown attribute

Let's just dont use it, if __CHECKER__ is defined.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The program parameter can be used to mark hardware samples with
some token.  Previously, it was used to mark guest samples only.

Improve the program parameter doubleword by combining two parts,
the leftmost LPP part and the rightmost PID part.  Set the PID
part for processes by using the task PID.
To distinguish host and guest samples for the kernel (PID part
is zero), the guest must always set the program paramater to a
non-zero value.  Use the leftmost bit in the LPP part of the
program parameter to be able to detect guest kernel samples.

[brueckner@linux.vnet.ibm.com]: Split __LC_CURRENT and introduced
__LC_LPP. Corrected __LC_CURRENT users and adjusted assembler parts.
And updated the commit message accordingly.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The use of OFFSET instead of DEFINE makes the definitions in asm-offsets.c
more readable. While we are at it sort the defines for struct _lowcore
according to the field order and remove some unneeded defines.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The sclp console and tty code currently uses several message text
objects in a single message event to print several lines with one
SCCB. This causes the output of these lines to be fused into a
block which is noticeable when selecting text in the operating system
message panel.

Instead use several message events with a single message text object
each to print every line on its own. This changes the SCCB layout
from

    struct sccb_header
        struct evbuf_header
            struct mdb_header
                struct go
                struct mto
		...
		struct mto

to

    struct sccb_header
        struct evbuf_header
            struct mdb_header
                struct go
                struct mto
	...
        struct evbuf_header
            struct mdb_header
                struct go
                struct mto
Reviewed-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Various functions in entry.S perform test-under-mask instructions
to test for particular bits in memory.  Because test-under-mask uses
a mask value of one byte, the mask value and the offset into the
memory must be calculated manually.  This easily introduces errors
and is hard to review and read.

Introduce the TSTMSK assembler macro to specify a mask constant and
let the macro calculate the offset and the byte mask to generate a
test-under-mask instruction.  The benefit is that existing symbolic
constants can now be used for tests.  Also the macro checks for
zero mask values and mask values that consist of multiple bytes.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Previously, the init task did not have an allocated FPU save area and
saving an FPU state was not possible.  Now if the vector extension is
always enabled, provide a static FPU save area to save FPU states of
vector instructions that can be executed quite early.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>