s390/time: Provide sched_clock_noinstr()

With the intent to provide local_clock_noinstr(), a variant of
local_clock() that's safe to be called from noinstr code (with the
assumption that any such code will already be non-preemptible),
prepare for things by providing a noinstr sched_clock_noinstr()
function.

Specifically, preempt_enable_*() calls out to schedule(), which upsets
noinstr validation efforts.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Michael Kelley <mikelley@microsoft.com> # Hyper-V
Link: https://lore.kernel.org/r/20230519102715.570170436@infradead.org

s390: define get_cycles macro for arch-override

S390x defines a get_cycles() function, but it does not do the usual
`#define get_cycles get_cycles` dance, making it impossible for generic
code to see if an arch-specific function was defined. While the
get_cycles() ifdef is not currently used, the following timekeeping
patch in this series will depend on the macro existing (or not existing)
when defining random_get_entropy().

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

s390: convert ".insn" encoding to instruction names

With z10 as minimum supported machine generation many ".insn" encodings
could be now converted to instruction names. There are couple of exceptions
- stfle is used from the als code built for z900 and cannot be converted
- few ".insn" directives encode unsupported instruction formats

The generated code is identical before/after this change.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390: raise minimum supported machine generation to z10

Machine generations up to z9 (released in May 2006) have been officially
out of service for several years now (z9 end of service - January 31, 2019).
No distributions build kernels supporting those old machine generations
anymore, except Debian, which seems to pick the oldest supported
generation. The team supporting Debian on s390 has been notified about
the change.

Raising minimum supported machine generation to z10 helps to reduce
maintenance cost and effectively remove code, which is not getting
enough testing coverage due to lack of older hardware and distributions
support. Besides that this unblocks some optimization opportunities and
allows to use wider instruction set in asm files for future features
implementation. Due to this change spectre mitigation and usercopy
implementations could be drastically simplified and many newer instructions
could be converted from ".insn" encoding to instruction names.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/timex: get rid of register asm

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time,idle: get rid of unsigned long long

Get rid of unsigned long long, and use unsigned long instead
everywhere. The usage of unsigned long long is a leftover from
31 bit kernel support.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/time: remove get_tod_clock_ext()

Remove get_tod_clock_ext() and the STORE_CLOCK_EXT_SIZE define. This
enforces all users of the existing low level functions to use a union
tod_clock.

This way there is now a compile time check for the correct time and
therefore also if the size of the argument matches what will be
written to by the STORE CLOCK EXTENDED instruction.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time: convert tod_clock_base to union

Convert tod_clock_base to union tod_clock. This simplifies quite a bit
of code and also fixes a bug in read_persistent_clock64();

void read_persistent_clock64(struct timespec64 *ts)
{
__u64 delta;

delta = initial_leap_seconds + TOD_UNIX_EPOCH;
get_tod_clock_ext(clk);
*(__u64 *) &clk[1] -= delta;
if (*(__u64 *) &clk[1] > delta)
clk[0]--;
ext_to_timespec64(clk, ts);
}

Assume &clk[1] == 3 and delta == 2; then after the substraction the if
condition becomes true and the epoch part of the clock is decremented
by one because of an assumed overflow, even though there is none.

Fix this by using 128 bit arithmetics and let the compiler do the
right thing:

void read_persistent_clock64(struct timespec64 *ts)
{
union tod_clock clk;
u64 delta;

delta = initial_leap_seconds + TOD_UNIX_EPOCH;
store_tod_clock_ext(&clk);
clk.eitod -= delta;
ext_to_timespec64(&clk, ts);
}

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time: introduce new store_tod_clock_ext()

Introduce new store_tod_clock_ext() function, which is the same like
store_tod_clock_ext_cc() except that it doesn't return a condition
code.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time: rename store_tod_clock_ext() and use union tod_clock

Rename store_tod_clock_ext() to store_tod_clock_ext_cc() to reflect
that it returns a condition code and also use union tod_clock as
parameter.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time: introduce union tod_clock

Introduce union tod_clock which is supposed to be used to decode and
access various fields of the result of STORE CLOCK EXTENDED.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time: use stcke instead of stck

Use STORE CLOCK EXTENDED instead of STORE CLOCK in early tod clock
setup. This is just to remove another usage of stck, trying to remove
all usages of STORE CLOCK. This doesn't fix anything.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/vdso: reimplement getcpu vdso syscall

Implement the previously removed getcpu vdso syscall by using the
TOD programmable field to pass the cpu number to user space.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

s390/time: remove unused function

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

s390/time: Fix clk type in get_tod_clock

Clang warns:

In file included from ../arch/s390/boot/startup.c:3:
In file included from ../include/linux/elf.h:5:
In file included from ../arch/s390/include/asm/elf.h:132:
In file included from ../include/linux/compat.h:10:
In file included from ../include/linux/time.h:74:
In file included from ../include/linux/time32.h:13:
In file included from ../include/linux/timex.h:65:
../arch/s390/include/asm/timex.h:160:20: warning: passing 'unsigned char
[16]' to parameter of type 'char *' converts between pointers to integer
types with different sign [-Wpointer-sign]
get_tod_clock_ext(clk);
^~~
../arch/s390/include/asm/timex.h:149:44: note: passing argument to
parameter 'clk' here
static inline void get_tod_clock_ext(char *clk)
^

Change clk's type to just be char so that it matches what happens in
get_tod_clock_ext.

Fixes: 57b28f66316d ("[S390] s390_hypfs: Add new attributes")
Link: https://github.com/ClangBuiltLinux/linux/issues/861
Link: http://lkml.kernel.org/r/20200208140858.47970-1-natechancellor@gmail.com
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/ftrace: fix endless recursion in function_graph tracer

The following sequence triggers a kernel stack overflow on s390x:

mount -t tracefs tracefs /sys/kernel/tracing
cd /sys/kernel/tracing
echo function_graph > current_tracer
[crash]

This is because preempt_count_{add,sub} are in the list of traced
functions, which can be demonstrated by:

echo preempt_count_add >set_ftrace_filter
echo function_graph > current_tracer
[crash]

The stack overflow happens because get_tod_clock_monotonic() gets called
by ftrace but itself calls preempt_{disable,enable}(), which leads to a
endless recursion. Fix this by using preempt_{disable,enable}_notrace().

Fixes: 011620688a71 ("s390/time: ensure get_clock_monotonic() returns monotonic values")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time: ensure get_clock_monotonic() returns monotonic values

The current implementation of get_clock_monotonic() leaves it up to
the caller to call the function with preemption disabled. The only
core kernel caller (sched_clock) however does not disable preemption.

In order to make sure that all callers of this function see monotonic
values handle disabling preemption within the function itself.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/time: remove monotonic_clock()

Remove unused monotonic_clock() function.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

s390/dasd: Change unsigned long long to unsigned long

Unsigned long long and unsigned long were different in size for 31-bit.
For 64-bit the size for both datatypes is 8 Bytes and since the support
for 31-bit is long gone we can clean up a little and change everything
to unsigned long.
Change get_phys_clock() along the way to accept unsigned long as well so
that the DASD code can be consistent.

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: add support for the TOD clock epoch extension

The TOD epoch extension adds 8 epoch bits to the TOD clock to provide
a continuous clock after 2042/09/17. The store-clock-extended (STCKE)
instruction will store the epoch index in the first byte of the
16 bytes stored by the instruction. The read_boot_clock64 and the
read_presistent_clock64 functions need to take the additional bits
into account to give the correct result after 2042/09/17.

The clock-comparator register will stay 64 bit wide. The comparison
of the clock-comparator with the TOD clock is limited to bytes
1 to 8 of the extended TOD format. To deal with the overflow problem
due to an epoch change the clock-comparator sign control in CR0 can
be used to switch the comparison of the 64-bit TOD clock with the
clock-comparator to a signed comparison.

The decision between the signed vs. unsigned clock-comparator
comparisons is done at boot time. Only if the TOD clock is in the
second half of a 142 year epoch the signed comparison is used.
This solves the epoch overflow issue as long as the machine is
booted at least once in an epoch.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/timex: micro optimization for tod_to_ns

The conversion of a TOD value to nano-seconds currently uses a 32/32 bit
split with the calculation for "nsecs = (TOD * 125) >> 9". Using a
55/9 bit split saves an instruction.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/debug: make debug event time stamps relative to the boot TOD clock

The debug features currently uses absolute TOD time stamps for the
debug events. Given that the TOD clock can jump forward and backward
due to STP sync checks the order of debug events can get obfuscated.

Replace the absolute TOD time stamps with a delta to the IPL time
stamp. On a STP sync check the TOD clock correction is added to
the IPL time stamp as well to make the deltas unaffected by STP
sync check.

The readout of the debug feature entries will convert the deltas
back to absolute time stamps based on the Unix epoch.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: Remove VLAIS in ptff() and clear_table()

The ptff() and clear_table() functions use the gcc extension "variable
length arrays in structures" (VLAIS) to define in the inline assembler
constraints the area of the clobbered memory. This extension will most
likely never be supported by LLVM/Clang.

Since currently BPF programs are compiled with LLVM, this leads to the
following compile errors:

$ cd samples/bpf
$ make

In file included from /root/linux-master/samples/bpf/tracex1_kern.c:8:
In file included from ./include/linux/netdevice.h:44:
...
In file included from ./arch/s390/include/asm/mmu_context.h:10:
./arch/s390/include/asm/pgalloc.h:30:24: error: fields must have a
constant size: 'variable length array in structure' extension will never
be supported
typedef struct { char _[n]; } addrtype;

In file included from /root/linux-master/samples/bpf/tracex1_kern.c:7:
In file included from ./include/linux/skbuff.h:18:
...
In file included from ./include/linux/jiffies.h:8:
In file included from ./include/linux/timex.h:65:
./arch/s390/include/asm/timex.h:105:24: error: fields must have a
constant size: 'variable length array in structure' extension will never
be supported
typedef struct { char _[len]; } addrtype;

To fix this do the following:

- Convert ptff() into a macro that then uses a fixed size array
when expanded.
- Convert the clear_table() function and use an inline assembly
with fixed size array in a loop.
The runtime performance of the new version is even better than
the old version (tested with EC12/z13 and gcc 4.8.5/6.2.1 with
"-march=z196 -O2").

Reported-by: Zvonko Kosic <zvonko.kosic@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: refactor clock sync

Merge clock_sync_cpu into stp_sync_clock and split out the update
of the global and per-CPU clock fields into clock_sync_global
and clock_sync_local.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: add leap seconds to initial system time

The PTFF instruction can be used to retrieve information about UTC
including the current number of leap seconds. Use this value to
convert the coordinated server time value of the TOD clock to a
proper UTC timestamp to initialize the system time. Without this
correction the system time will be off by the number of leap seonds
until it has been corrected via NTP.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: LPAR offset handling

It is possible to specify a user offset for the TOD clock, e.g. +2 hours.
The TOD clock will carry this offset even if the clock is synchronized
with STP. This makes the time stamps acquired with get_sync_clock()
useless as another LPAR migth use a different TOD offset.

Use the PTFF instrution to get the TOD epoch difference and subtract
it from the TOD clock value to get a physical timestamp. As the epoch
difference contains the sync check delta as well the LPAR offset value
to the physical clock needs to be refreshed after each clock
synchronization.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: move PTFF definitions

The PTFF instruction is not a function of ETR, rename and move the
PTFF definitions from etr.h to timex.h.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: time: Provide read_boot_clock64() and read_persistent_clock64()

As part of addressing the "y2038 problem" for in-kernel uses,
this patch converts read_boot_clock() to read_boot_clock64()
and read_persistent_clock() to read_persistent_clock64() using
timespec64.

Rename some instances of 'timespec' to 'timespec64' in time.c and
related references

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
[jstultz: Fixed minor style and grammer tweaks
pointed out by Ingo]
Signed-off-by: John Stultz <john.stultz@linaro.org>

s390/timex: fix get_tod_clock_ext() inline assembly

For C language, it treats array parameter as a pointer, so sizeof for an
array parameter is equal to sizeof for a pointer, which causes compiler
warning (with allmodconfig by gcc 5):

./arch/s390/include/asm/timex.h: In function 'get_tod_clock_ext':
./arch/s390/include/asm/timex.h:76:32: warning: 'sizeof' on array function parameter 'clk' will return size of 'char *' [-Wsizeof-array-argument]
typedef struct { char _[sizeof(clk)]; } addrtype;
^
Can use macro CLOCK_STORE_SIZE instead of all related hard code numbers,
which also can avoid this warning. And also add a tab to CLOCK_TICK_RATE
definition to match coding styles.

[heiko.carstens@de.ibm.com]:
Chen's patch actually fixes a bug within the get_tod_clock_ext() inline assembly
where we incorrectly tell the compiler that only 8 bytes of memory get changed
instead of 16 bytes.
This would allow gcc to generate incorrect code. Right now this doesn't seem to
be the case.
Also slightly changed the patch a bit.
- renamed CLOCK_STORE_SIZE to STORE_CLOCK_EXT_SIZE
- changed get_tod_clock_ext() to receive a char pointer parameter

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: fix get_tod_clock_ext inline assembly

The get_tod_clock_ext inline assembly does not specify its output
operands correctly. This can cause incorrect code to be generated.

Cc: stable@vger.kernel.org # 3.12
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: correct use of store clock fast

The result of the store-clock-fast (STCKF) instruction is a bit fuzzy.
It can happen that the value stored on one CPU is smaller than the value
stored on another CPU, although the order of the stores is the other
way around. This can cause deltas of get_tod_clock() values to become
negative when they should not be.

We need to be more careful with store-clock-fast, this patch partially
reverts git commit e4b7b4238e666682555461fa52eecd74652f36bb "time:
always use stckf instead of stck if available". The get_tod_clock()
function now uses the store-clock-extended (STCKE) instruction.
get_tod_clock_fast() can be used if the fuzziness of store-clock-fast
is acceptable e.g. for wait loops local to a CPU.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: rename tod clock access functions

Fix name clash with some common code device drivers and add "tod"
to all tod clock access function names.

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

s390/time: fix sched_clock() overflow

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

s390/comments: unify copyright messages and remove file names

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 <heiko.carstens@de.ibm.com>

s390/time: simply Kconfig dependency

Use HAVE_MARCH_Z9_109_FEATURES to figure out if stckf is available
at compile time.

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

s390/time: always use stckf instead of stck if available

The store clock fast instruction saves a couple of instructions compared
to the store clock instruction. Always use stckf instead of stck if it
is available.

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

[S390] avoid STCKF if running in ESA mode

In ESA mode STCKF is not defined even if the facility bit is enabled.
To prevent an illegal operation we must also check if we run a 64 bit kernel.
To make the check perform well add the STCKF bit to the machine flags.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] Introduce get_clock_fast()

Add get_clock_fast() which uses the slightly faster stckf if available.
If stckf is not available fall back to stck, which has the same width.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] time: let local_tick_enable/disable() reprogram the clock comparator

Let local_tick_enable/disable() reprogram the clock comparator so the
function names make semantically more sense.
Also that way the functions are more symmetric since normally each
local_tick_enable() call usually would have a subsequent call to
set_clock_comparator() anyway.

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

[S390] time: move local_tick_enable()/disable() to timex.h

Move the two functions to timex.h where they make more sense than in
hardirq.h.
No functional change.

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

[S390] s390_hypfs: Add new attributes

In order to access the data of the hypfs diagnose calls from user
space also in binary form, this patch adds two new attributes in
debugfs:
* z/VM: s390_hypfs/d2fc_bin
* LPAR: s390_hypfs/d204_bin

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] use inline assembly contraints available with gcc 3.3.3

Drop support to compile the kernel with gcc versions older than 3.3.3.
This allows us to use the "Q" inline assembly contraint on some more
inline assemblies without duplicating a lot of complex code (e.g. __xchg
and __cmpxchg). The distinction for older gcc versions can be removed
which saves a few lines and simplifies the code.

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

[S390] introduce get_clock_monotonic

Introduce get_clock_monotonic() function which can be used to get a
(fast) timestamp. Resolution is the same as for get_clock(). The
only difference is that the timestamps are monotonic and don't jump
backward or forward.

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

[SCSI] zfcp: Remove duplicated code for debug timestamps

The timestamp calculation used for s390dbf output is the same in a
private zfcp function and in debug.c. Replace both with a common
inline function.

Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

[S390] add read_persistent_clock

Add a read_persistent_clock function that does not just return 0.
Since timekeeping_init calls the function before time_init has been
called move reset_tod_clock to early.c to make sure that the TOD
clock is running when read_persistent_clock is invoked.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] move include/asm-s390 to arch/s390/include/asm

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>