Merge tag 's390-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Vasily Gorbik:

 - Improve stop_machine wait logic: replace cpu_relax_yield call in
   generic stop_machine function with a weak stop_machine_yield
   function. This is overridden on s390, which yields the current cpu to
   the neighbouring cpu after a couple of retries, instead of blindly
   giving up the cpu to the hipervisor. This significantly improves
   stop_machine performance on s390 in overcommitted scenarios.

   This includes common code changes which have been Acked by Peter
   Zijlstra and Thomas Gleixner.

 - Improve jump label transformation speed: transform jump labels
   without using stop_machine.

 - Refactoring of the vfio-ccw cp handling, simplifying the code and
   avoiding unneeded allocating/copying.

 - Various vfio-ccw fixes (ccw translation, state machine).

 - Add support for vfio-ap queue interrupt control in the guest. This
   includes s390 kvm changes which have been Acked by Christian
   Borntraeger.

 - Add protected virtualization support for virtio-ccw.

 - Enforce both CONFIG_SMP and CONFIG_HOTPLUG_CPU, which allows to
   remove some code which most likely isn't working at all, besides that
   s390 didn't even compile for !CONFIG_SMP.

 - Support for special flagged EP11 CPRBs for zcrypt.

 - Handle PCI devices with no support for new MIO instructions.

 - Avoid KASAN false positives in reworked stack unwinder.

 - Couple of fixes for the QDIO layer.

 - Convert s390 specific documentation to ReST format.

 - Let s390 crypto modules return -ENODEV instead of -EOPNOTSUPP if
   hardware is missing. This way our modules behave like most other
   modules and which is also what systemd's systemd-modules-load.service
   expects.

 - Replace defconfig with performance_defconfig, so there is one config
   file less to maintain.

 - Remove the SCLP call home device driver, which was never useful.

 - Cleanups all over the place.

* tag 's390-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (83 commits)
  docs: s390: s390dbf: typos and formatting, update crash command
  docs: s390: unify and update s390dbf kdocs at debug.c
  docs: s390: restore important non-kdoc parts of s390dbf.rst
  vfio-ccw: Fix the conversion of Format-0 CCWs to Format-1
  s390/pci: correctly handle MIO opt-out
  s390/pci: deal with devices that have no support for MIO instructions
  s390: ap: kvm: Enable PQAP/AQIC facility for the guest
  s390: ap: implement PAPQ AQIC interception in kernel
  vfio: ap: register IOMMU VFIO notifier
  s390: ap: kvm: add PQAP interception for AQIC
  s390/unwind: cleanup unused READ_ONCE_TASK_STACK
  s390/kasan: avoid false positives during stack unwind
  s390/qdio: don't touch the dsci in tiqdio_add_input_queues()
  s390/qdio: (re-)initialize tiqdio list entries
  s390/dasd: Fix a precision vs width bug in dasd_feature_list()
  s390/cio: introduce driver_override on the css bus
  vfio-ccw: make convert_ccw0_to_ccw1 static
  vfio-ccw: Remove copy_ccw_from_iova()
  vfio-ccw: Factor out the ccw0-to-ccw1 transition
  vfio-ccw: Copy CCW data outside length calculation
  ...

1 files changed, 86 insertions, 19 deletions

diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 0ebf08c3b35e..6d321f5f101d 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -647,11 +647,23 @@ static int debug_close(struct inode *inode, struct file *file)
 	return 0; /* success */
 }
 
-/*
- * debug_register_mode:
- * - Creates and initializes debug area for the caller
- *   The mode parameter allows to specify access rights for the s390dbf files
- * - Returns handle for debug area
+/**
+ * debug_register_mode() - creates and initializes debug area.
+ *
+ * @name:	Name of debug log (e.g. used for debugfs entry)
+ * @pages_per_area:	Number of pages, which will be allocated per area
+ * @nr_areas:	Number of debug areas
+ * @buf_size:	Size of data area in each debug entry
+ * @mode:	File mode for debugfs files. E.g. S_IRWXUGO
+ * @uid:	User ID for debugfs files. Currently only 0 is supported.
+ * @gid:	Group ID for debugfs files. Currently only 0 is supported.
+ *
+ * Return:
+ * - Handle for generated debug area
+ * - %NULL if register failed
+ *
+ * Allocates memory for a debug log.
+ * Must not be called within an interrupt handler.
  */
 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
 				  int nr_areas, int buf_size, umode_t mode,
@@ -681,10 +693,21 @@ out:
 }
 EXPORT_SYMBOL(debug_register_mode);
 
-/*
- * debug_register:
- * - creates and initializes debug area for the caller
- * - returns handle for debug area
+/**
+ * debug_register() - creates and initializes debug area with default file mode.
+ *
+ * @name:	Name of debug log (e.g. used for debugfs entry)
+ * @pages_per_area:	Number of pages, which will be allocated per area
+ * @nr_areas:	Number of debug areas
+ * @buf_size:	Size of data area in each debug entry
+ *
+ * Return:
+ * - Handle for generated debug area
+ * - %NULL if register failed
+ *
+ * Allocates memory for a debug log.
+ * The debugfs file mode access permissions are read and write for user.
+ * Must not be called within an interrupt handler.
  */
 debug_info_t *debug_register(const char *name, int pages_per_area,
 			     int nr_areas, int buf_size)
@@ -694,9 +717,13 @@ debug_info_t *debug_register(const char *name, int pages_per_area,
 }
 EXPORT_SYMBOL(debug_register);
 
-/*
- * debug_unregister:
- * - give back debug area
+/**
+ * debug_unregister() - give back debug area.
+ *
+ * @id:		handle for debug log
+ *
+ * Return:
+ *    none
  */
 void debug_unregister(debug_info_t *id)
 {
@@ -745,9 +772,14 @@ out:
 	return rc;
 }
 
-/*
- * debug_set_level:
- * - set actual debug level
+/**
+ * debug_set_level() - Sets new actual debug level if new_level is valid.
+ *
+ * @id:		handle for debug log
+ * @new_level:	new debug level
+ *
+ * Return:
+ *    none
  */
 void debug_set_level(debug_info_t *id, int new_level)
 {
@@ -873,6 +905,14 @@ static struct ctl_table s390dbf_dir_table[] = {
 
 static struct ctl_table_header *s390dbf_sysctl_header;
 
+/**
+ * debug_stop_all() - stops the debug feature if stopping is allowed.
+ *
+ * Return:
+ * -   none
+ *
+ * Currently used in case of a kernel oops.
+ */
 void debug_stop_all(void)
 {
 	if (debug_stoppable)
@@ -880,6 +920,17 @@ void debug_stop_all(void)
 }
 EXPORT_SYMBOL(debug_stop_all);
 
+/**
+ * debug_set_critical() - event/exception functions try lock instead of spin.
+ *
+ * Return:
+ * -   none
+ *
+ * Currently used in case of stopping all CPUs but the current one.
+ * Once in this state, functions to write a debug entry for an
+ * event or exception no longer spin on the debug area lock,
+ * but only try to get it and fail if they do not get the lock.
+ */
 void debug_set_critical(void)
 {
 	debug_critical = 1;
@@ -1036,8 +1087,16 @@ debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *stri
 }
 EXPORT_SYMBOL(__debug_sprintf_exception);
 
-/*
- * debug_register_view:
+/**
+ * debug_register_view() - registers new debug view and creates debugfs
+ *			   dir entry
+ *
+ * @id:		handle for debug log
+ * @view:	pointer to debug view struct
+ *
+ * Return:
+ * -   0  : ok
+ * -   < 0: Error
  */
 int debug_register_view(debug_info_t *id, struct debug_view *view)
 {
@@ -1077,8 +1136,16 @@ out:
 }
 EXPORT_SYMBOL(debug_register_view);
 
-/*
- * debug_unregister_view:
+/**
+ * debug_unregister_view() - unregisters debug view and removes debugfs
+ *			     dir entry
+ *
+ * @id:		handle for debug log
+ * @view:	pointer to debug view struct
+ *
+ * Return:
+ * -   0  : ok
+ * -   < 0: Error
  */
 int debug_unregister_view(debug_info_t *id, struct debug_view *view)
 {