1030234 Commits

Author SHA1 Message Date
Julian Wiedmann
44d9a21a19 s390/qdio: consolidate QIB code
Move all QIB-related code into qdio_setup_qib(), and slightly re-order
it according to the order of the struct's fields. This makes it easier
to understand what the QIB actually looks like before we send it to HW.

Also get rid of the qebsm_possible() helper - as 31-bit support is long
gone, the comment doesn't make any sense. And while removing some stale
QIB-related comment, also move the clearing of the QDR into its proper
place.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:28 +02:00
Julian Wiedmann
f86991b3a9 s390/qdio: use dev_info() in qdio_print_subchannel_info()
Prefer dev_info() over a raw printk. This also adds the device and
driver names into the output, so that we have:

Before:
    qdio: 0.0.17c0 ZFCP on SC 17 using [...]

After:
    zfcp 0.0.17c0: qdio: ZFCP on SC 17 using [...]

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:28 +02:00
Julian Wiedmann
87e225bfa0 s390/qdio: fine-tune the queue sync
Push the sync check from qdio_inspect_queue() down into the two
get_*_buffer_frontier() code paths, where we actually need the sync to
look at the current queue state. This lets us avoid the check when we
know that there is no work on the queue (ie. when q->nr_buf_used is 0).

While at it introduce the qdio_sync_*_queue() helpers, so that we can
avoid the branch on q->is_input_q when we already know the queue type.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:28 +02:00
Julian Wiedmann
10376b5350 s390/qdio: clean up SIGA capability tracking
Don't bother with translating the SIGA-related capability bits into
our own internal format, just cache the full qdioac1 field instead.

Also adjust the helper macros so that they take a qdio_irq argument
and can be used everywhere, instead of taking a qdio_q and then
internally dereferencing the parent pointer.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:28 +02:00
Julian Wiedmann
e2af48df5c s390/qdio: remove unused sync-after-IRQ infrastructure
The queue processing is fully decoupled from any preceding interrupt,
so we're no longer making any use of the sync-after-IRQ HW capabilities.

And as SIGA-sync is a legacy feature, there's also not much point in
re-designing the driver & qdio-layer code just so that we can
potentially avoid a few syncs. So just remove all the leftover code.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:28 +02:00
Julian Wiedmann
eade5f61a5 s390/qdio: use absolute data address in ESTABLISH ccw
Clean up yet another path where HW wants an absolute address, and we've
been implicitly relying on V=R.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:27 +02:00
Vineeth Vijayan
d3683c0552 s390/cio: add dev_busid sysfs entry for each subchannel
Introduce dev_busid, which exports the device-id associated with the
io-subchannel (and message-subchannel). The dev_busid indicates that of
the device which may be physically installed on the corrosponding
subchannel. The dev_busid value "none" indicates that the subchannel
is not valid, there is no I/O device currently associated with the
subchannel.

The dev_busid information would be helpful to write device-specific
udev-rules associated with the subchannel. The dev_busid interface would
be available even when the sch is not bound to any driver or if there is
no operational device connected on it. Hence this attribute can be used to
write udev-rules which are specific to the device associated with the
subchannel.

Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:27 +02:00
Vineeth Vijayan
cec0c58d34 s390/cio: add rescan functionality on channel subsystem
This patch introduces a new rescan sys-interface for channel-subsystem.
The rescan interface allows the user to invoke an evaluation of all
subchannels defined in the I/O configuration.

The new rescan interface can be found at /sys/devices/css0/rescan
and can be triggered by,

echo > /sys/devices/css0/rescan

Writing to this interface triggers subchannel evaluation. The write
request completes only after scan-related work has completed

This user-invoked subchannel evaluation allows manual recovery in error
situations such as:
 - restart of device discovery after resolution of temporary device
   error
 - inconsistent OS view of subchannel state due to missing state-change
   interrupts (CRWs)

Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-18 10:01:27 +02:00
Heiko Carstens
c78d0c7484 s390: rename dma section to amode31
The dma section name is confusing, since the code which resides within
that section has nothing to do with direct memory access.  Instead the
limitation is that the code has to run in 31 bit addressing mode, and
therefore has to reside below 2GB.  So the name was chosen since
ZONE_DMA is the same region.

To reduce confusion rename the section to amode31, which hopefully
describes better what this is about.

Note: this will also change vmcoreinfo strings
- SDMA=... gets renamed to SAMODE31=...
- EDMA=... gets renamed to EAMODE31=...

Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-05 14:10:53 +02:00
Heiko Carstens
cfafad6d78 s390/mm: use page_to_virt() in __kernel_map_pages()
Fix virtual vs physical address confusion (which currently are the same).

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-05 14:10:53 +02:00
Sebastian Andrzej Siewior
52b6defae7 s390/sclp: replace deprecated CPU-hotplug functions
The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-6-bigeasy@linutronix.de
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-05 14:10:53 +02:00
Sebastian Andrzej Siewior
a73de29320 s390: replace deprecated CPU-hotplug functions
The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-5-bigeasy@linutronix.de
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-05 14:10:53 +02:00
Ilya Leoshkevich
de5012b41e s390/ftrace: implement hotpatching
s390 allows hotpatching the mask of a conditional jump instruction.
Make use of this feature in order to avoid the expensive stop_machine()
call.

The new trampolines are split in 3 stages:

- A first stage is a 6-byte relative conditional long branch located at
  each function's entry point. Its offset always points to the second
  stage for the corresponding function, and its mask is either all 0s
  (ftrace off) or all 1s (ftrace on). The code for flipping the mask is
  borrowed from ftrace_{enable,disable}_ftrace_graph_caller. After
  flipping, ftrace_arch_code_modify_post_process() syncs with all the
  other CPUs by sending SIGPs.

- Second stages for vmlinux are stored in a separate part of the .text
  section reserved by the linker script, and in dynamically allocated
  memory for modules. This prevents the icache pollution. The total
  size of second stages is about 1.5% of that of the kernel image.

  Putting second stages in the .bss section is possible and decreases
  the size of the non-compressed vmlinux, but splits the kernel 1:1
  mapping, which is a bad tradeoff.

  Each second stage contains a call to the third stage, a pointer to
  the part of the intercepted function right after the first stage, and
  a pointer to an interceptor function (e.g. ftrace_caller).

  Second stages are 8-byte aligned for the future direct calls
  implementation.

- There are only two copies of the third stage: in the .text section
  for vmlinux and in dynamically allocated memory for modules. It can be
  an expoline, which is relatively large, so inlining it into each
  second stage is prohibitively expensive.

As a result of this organization, phoronix-test-suite with ftrace off
does not show any performance degradation.

Suggested-by: Sven Schnelle <svens@linux.ibm.com>
Suggested-by: Vasily Gorbik <gor@linux.ibm.com>
Co-developed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20210728212546.128248-3-iii@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-03 14:31:40 +02:00
Ilya Leoshkevich
67ccddf866 ftrace: Introduce ftrace_need_init_nop()
Implementing live patching on s390 requires each function's prologue to
contain a very special kind of nop, which gcc and clang don't generate.
However, the current code assumes that if CC_USING_NOP_MCOUNT is
defined, then whatever the compiler generates is good enough.

Move the CC_USING_NOP_MCOUNT check into the new ftrace_need_init_nop()
macro, that the architectures can override.

An alternative solution is to disable using -mnop-mcount in the
Makefile, however, this makes the build logic (even) more complicated
and forces the arch-specific code to deal with the useless __fentry__
symbol.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20210728212546.128248-2-iii@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-03 14:31:40 +02:00
Masahiro Yamada
d80d3ea64e s390: move the install rule to arch/s390/Makefile
Currently, the install target in arch/s390/Makefile descends into
arch/s390/boot/Makefile to invoke the shell script, but there is no
good reason to do so.

arch/s390/Makefile can run the shell script directly.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210729142338.446002-1-masahiroy@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:36 +02:00
Ilya Leoshkevich
e37b3dd063 s390: enable KCSAN
s390x GCC and SystemZ Clang have ThreadSanitizer support now [1] [2],
so enable KCSAN for s390.

[1] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ea22954e7c58
[2] https://reviews.llvm.org/D105629

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:23 +02:00
Heiko Carstens
09b1b13461 kcsan: use u64 instead of cycles_t
cycles_t has a different type across architectures: unsigned int,
unsinged long, or unsigned long long. Depending on architecture this
will generate this warning:

kernel/kcsan/debugfs.c: In function ‘microbenchmark’:
./include/linux/kern_levels.h:5:25: warning: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 3 has type ‘cycles_t’ {aka ‘long unsigned int’} [-Wformat=]

To avoid this simply change the type of cycle to u64 in microbenchmark(),
since u64 is of type unsigned long long for all architectures.

Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20210729142811.1309391-1-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:02 +02:00
Sven Schnelle
d6de72cf92 s390: add kfence region to pagetable dumper
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Link: https://lore.kernel.org/r/20210728190254.3921642-5-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:02 +02:00
Sven Schnelle
e41ba1115a s390: add support for KFENCE
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
[hca@linux.ibm.com: simplify/rework code]
Link: https://lore.kernel.org/r/20210728190254.3921642-4-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:02 +02:00
Sven Schnelle
f99e12b21b kfence: add function to mask address bits
s390 only reports the page address during a translation fault.
To make the kfence unit tests pass, add a function that might
be implemented by architectures to mask out address bits.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20210728190254.3921642-3-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:01 +02:00
Heiko Carstens
b3e1a00c8f s390/mm: implement set_memory_4k()
Implement set_memory_4k() which will split any present large or huge
mapping in the given range to a 4k mapping.

Link: https://lore.kernel.org/r/20210728190254.3921642-2-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:01 +02:00
Marco Elver
00e67bf030 kfence, x86: only define helpers if !MODULE
x86's <asm/tlbflush.h> only declares non-module accessible functions
(such as flush_tlb_one_kernel) if !MODULE.

In preparation of including <asm/kfence.h> from the KFENCE test module,
only define the helpers if !MODULE to avoid breaking the build with
CONFIG_KFENCE_KUNIT_TEST=m.

Signed-off-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/YQJdarx6XSUQ1tFZ@elver.google.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30 17:09:01 +02:00
Heiko Carstens
3da77cf33c s390/delay: get rid of not needed header includes
After all the changes to delay.c there are many includes which are not
needed anymore. Get rid of them.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:22 +02:00
Heiko Carstens
6ab023641a s390/boot: get rid of arithmetics on function pointers
sparse warning:
  CHECK   arch/s390/boot/startup.c
arch/s390/boot/startup.c:283:39: error: arithmetics on pointers to functions

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:22 +02:00
Ilya Leoshkevich
243fdac593 s390/headers: fix code style in module.h
struct brace should be on the same line.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:21 +02:00
Heiko Carstens
7e82523f25 s390/hwcaps: make sie capability regular hwcap
Commit 7f16d7e787b7 ("s390: show virtualization support in /proc/cpuinfo")
introduced special handling for sie capability, saying this should not be
exposed via hwcaps, without giving a reason.

However this leads to an inconsistent /proc/cpuinfo features line
where all features except the sie capability are also present in
hwcaps. I really don't see a reason to not add that to hwcaps - it
might be quite pointless, but at least this way it is possible to get
rid of some special handling.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:21 +02:00
Heiko Carstens
98ac9169e5 s390/hwcaps: remove hwcap stfle check
Remove the not so obvious "(elf_hwcap & (1UL << 2)" which only checks
if stfle is available. This used to be required for old code before
test_facility() was introduced. test_facility() will do the right
thing, regardless if stfle is available or not.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:21 +02:00
Heiko Carstens
487dff5638 s390/hwcaps: remove z/Architecture mode active check
Remove a leftover from the common 31/64 bit code. z/Architecture mode
is now always active, there is no need to check.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:21 +02:00
Heiko Carstens
449fbd713f s390/hwcaps: use consistent coding style / remove comments
Use a consistent coding style within setup_hwcaps() and remove obvious
and outdated comments.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:21 +02:00
Heiko Carstens
251527c9b0 s390/hwcaps: open code initialization of first six hwcap bits
The first six hwcap bits are initialized in a rather odd way: an array
contains the stfl(e) bits which need to be set, so that the
corresponding bit position (= array index) within hwcaps are set.

Better open code it like it is done for all other bits, making it
obvious which bit is set when.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:21 +02:00
Heiko Carstens
873129ca7b s390/hwcaps: split setup_hwcaps()
setup_hwcaps() is a quite large function. Make it smaller by moving
the elf platform setup code into an independent setup function.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:20 +02:00
Heiko Carstens
f17a6d5d83 s390/hwcaps: move setup_hwcaps()
Move setup_hwcaps() to processor.c for two reasons:
- make setup.c a bit smaller
- have allmost all of the hwcap code in one file

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:20 +02:00
Heiko Carstens
c68d463286 s390/hwcaps: add sanity checks
Add BUILD_BUG_ON() sanity checks to make sure the hwcap string array
contains a string for each hwcap.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:20 +02:00
Heiko Carstens
95655495e4 s390/hwcaps: use named initializers for hwcap string arrays
Use named initializers to make it obvious which hwcap string array
element belongs to which hwcap.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:20 +02:00
Heiko Carstens
47af00ef42 s390/hwcaps: introduce HWCAP bit numbers
Introduce HWCAP bit numbers, making it easier to tell at which bit
number we currently are. Also use these bits with the BIT macro to
define the real HWCAP masks.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:20 +02:00
Heiko Carstens
511ad531af s390/hwcaps: shorten HWCAP defines
Remove s390 part of all HWCAP defines, just to make them shorter and
easier to handle. The namespace is anyway per architecture.
This is similar to what arm64 has.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:20 +02:00
Niklas Schnelle
7e8403ecaf s390: add HWCAP_S390_PCI_MIO to ELF hwcaps
In order to support the use of enhanced PCI instructions in both kernel-
and userspace we need both hardware support and proper setup in the
kernel. The latter can be toggled off with the pci=nomio command line
option.

Thus availability of this feature in userspace depends on all of kernel
configuration (CONFIG_PCI), hardware support and the current kernel
command line and can thus not rely solely on a facility bit. Instead
let's introduce a new ELF hardware capability bit HWCAP_S390_PCI_MIO to
tell userspace whether these PCI instructions can be used.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:19 +02:00
Niklas Schnelle
3322ba0d7b s390: make PCI mio support a machine flag
Kernel support for the newer PCI mio instructions can be toggled off
with the pci=nomio command line option which needs to integrate with
common code PCI option parsing. However this option then toggles static
branches which can't be toggled yet in an early_param() call.

Thus commit 9964f396f1d0 ("s390: fix setting of mio addressing control")
moved toggling the static branches to the PCI init routine.

With this setup however we can't check for mio support outside the PCI
code during early boot, i.e. before switching the static branches, which
we need to be able to export this as an ELF HWCAP.

Improve on this by turning mio availability into a machine flag that
gets initially set based on CONFIG_PCI and the facility bit and gets
toggled off if pci=nomio is found during PCI option parsing allowing
simple access to this machine flag after early init.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:19 +02:00
Heiko Carstens
196e3c6ad1 s390/disassembler: add instructions
Add more instructions to the kernel disassembler.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:19 +02:00
Heiko Carstens
b3bc7980f4 s390: report more CPU capabilities
Add hardware capability bits and feature tags to /proc/cpuinfo
for NNPA and Vector-Packed-Decimal-Enhancement Facility 2.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:19 +02:00
Julian Wiedmann
0d374381d0 s390/qdio: remove unused macros
These macros haven't seen any use in a long time. Also note that the
queue_irqs_*() ones wouldn't even compile anymore.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:19 +02:00
Julian Wiedmann
bdfd740c1d s390/qdio: clarify reporting of errors to the drivers
Now that all drivers use qdio_inspect_queue() and qdio's internal
queue tasklets are gone, the driver-specified queue handlers are
only called for async error reporting (eg. for an error condition in
the QEBSM code).

So take a moment to clean up the Output Queue handlers (they are
_always_ called with qdio_error != 0), and clarify which error types
can be reported through what interface. As Benjamin already suggested
a while ago, we should turn these into distinct enums at some point.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:18 +02:00
Julian Wiedmann
0ae8f2af26 s390/qdio: remove unneeded siga-sync for Output Queue
get_outbound_buffer_frontier() is only reached via qdio_inspect_queue(),
and there we already call qdio_siga_sync_q() unconditionally.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:18 +02:00
Julian Wiedmann
d01fad2c6a s390/qdio: remove remaining tasklet & timer code
Both qdio drivers have moved away from using qdio's internal tasklet
and timer mechanisms for Output Queues. Rip out all the leftovers.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:18 +02:00
Julian Wiedmann
d1ea9b58c8 s390/qdio: propagate error when cancelling a ccw fails
If qdio_cancel_ccw() times out (or is interrupted) before the interrupt
for the {halt,clear} action arrives, report this back to the caller as
an error.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:18 +02:00
Julian Wiedmann
d06314e0ce s390/qdio: improve roll-back after error on ESTABLISH ccw
If the ESTABLISH ccw fails (ie. the qdio_irq is set to
QDIO_IRQ_STATE_ERR), we don't need to call qdio_shutdown() for rolling
back our earlier actions. All the needed logic is already available in
qdio_establish()'s error chain, and using it means we don't have to
temporarily drop the setup_mutex either.

This makes qdio_shutdown() a purely external function, that should only
be called by the driver if an earlier qdio_establish() succeeded.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:18 +02:00
Julian Wiedmann
1c1dc8bda3 s390/qdio: cancel the ESTABLISH ccw after timeout
When the ESTABLISH ccw does not complete within the specified timeout,
try our best to cancel the ccw program that is still active on the
device. Otherwise the IO subsystem might be accessing it even after
the driver eg. called qdio_free().

Fixes: 779e6e1c724d ("[S390] qdio: new qdio driver.")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 2.6.27
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:18 +02:00
Julian Wiedmann
2c197870e4 s390/qdio: fix roll-back after timeout on ESTABLISH ccw
When qdio_establish() times out while waiting for the ESTABLISH ccw to
complete, it calls qdio_shutdown() to roll back all of its previous
actions. But at this point the qdio_irq's state is still
QDIO_IRQ_STATE_INACTIVE, so qdio_shutdown() will exit immediately
without doing any actual work.

Which means that eg. the qdio_irq's thinint-indicator stays registered,
and cdev->handler isn't restored to its old value. And since
commit 954d6235be41 ("s390/qdio: make thinint registration symmetric")
the qdio_irq also stays on the tiq_list, so on the next qdio_establish()
we might get a helpful BUG from the list-debugging code:

...
[ 4633.512591] list_add double add: new=00000000005a4110, prev=00000001b357db78, next=00000000005a4110.
[ 4633.512621] ------------[ cut here ]------------
[ 4633.512623] kernel BUG at lib/list_debug.c:29!
...
[ 4633.512796]  [<00000001b2c6ee9a>] __list_add_valid+0x82/0xa0
[ 4633.512798] ([<00000001b2c6ee96>] __list_add_valid+0x7e/0xa0)
[ 4633.512800]  [<00000001b2fcecce>] qdio_establish_thinint+0x116/0x190
[ 4633.512805]  [<00000001b2fcbe58>] qdio_establish+0x128/0x498
...

Fix this by extracting a goto-chain from the existing error exits in
qdio_establish(), and check the return value of the wait_event_...()
to detect the timeout condition.

Fixes: 779e6e1c724d ("[S390] qdio: new qdio driver.")
Root-caused-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 2.6.27
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:17 +02:00
Alexander Egorenkov
f1a5469474 s390/setup: don't reserve memory that occupied decompressor's head
There is no useful information within [STARTUP_NORMAL_OFFSET, HEAD_END] now.

But the memory region [0, STARTUP_NORMAL_OFFSET] is used by:
* lowcore
* kdump for swapping memory
* stand-alone zipl dumpers for code, data, stack and heap

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:17 +02:00
Alexander Egorenkov
6bda667037 s390/boot: move dma sections from decompressor to decompressed kernel
This change simplifies the task of making the decompressor relocatable.

The decompressor's image contains special DMA sections between _sdma and
_edma. This DMA segment is loaded at boot as part of the decompressor and
then simply handed over to the decompressed kernel. The decompressor itself
never uses it in any way. The primary reason for this is the need to keep
the aforementioned DMA segment below 2GB which is required by architecture,
and because the decompressor is always loaded at a fixed low physical
address, it is guaranteed that the DMA region will not cross the 2GB
memory limit. If the DMA region had been placed in the decompressed kernel,
then KASLR would make this guarantee impossible to fulfill or it would
be restricted to the first 2GB of memory address space.

This commit moves all DMA sections between _sdma and _edma from
the decompressor's image to the decompressed kernel's image. The complete
DMA region is placed in the init section of the decompressed kernel and
immediately relocated below 2GB at start-up before it is needed by other
parts of the decompressed kernel. The relocation of the DMA region happens
even if the decompressed kernel is already located below 2GB in order
to keep the first implementation simple. The relocation should not have
any noticeable impact on boot time because the DMA segment is only a couple
of pages.

After relocating the DMA sections, the kernel has to fix all references
which point into it. In order to automate this, place all variables
pointing into the DMA sections in a special .dma.refs section. All such
variables must be defined using the new __dma_ref macro. Only variables
containing addresses within the DMA sections must be placed in the new
.dma.refs section.

Furthermore, move the initialization of control registers from
the decompressor to the decompressed kernel because some control registers
reference tables that must be placed in the DMA data section to
guarantee that their addresses are below 2G. Because the decompressed
kernel relocates the DMA sections at startup, the content of control
registers CR2, CR5 and CR15 must be updated with new addresses after
the relocation. The decompressed kernel initializes all control registers
early at boot and then updates the content of CR2, CR5 and CR15
as soon as the DMA relocation has occurred. This practically reverts
the commit a80313ff91ab ("s390/kernel: introduce .dma sections").

Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27 09:39:17 +02:00