Merge tag 's390-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Vasily Gorbik:

 - Add support for ftrace with direct call and ftrace direct call
   samples.

 - Add support for kernel command lines longer than current 896 bytes
   and make its length configurable.

 - Add support for BEAR enhancement facility to improve last breaking
   event instruction tracking.

 - Add kprobes sanity checks and testcases to prevent kprobe in the mid
   of an instruction.

 - Allow concurrent access to /dev/hwc for the CPUMF users.

 - Various ftrace / jump label improvements.

 - Convert unwinder tests to KUnit.

 - Add s390_iommu_aperture kernel parameter to tweak the limits on
   concurrently usable DMA mappings.

 - Add ap.useirq AP module option which can be used to disable interrupt
   use.

 - Add add_disk() error handling support to block device drivers.

 - Drop arch specific and use generic implementation of strlcpy and
   strrchr.

 - Several __pa/__va usages fixes.

 - Various cio, crypto, pci, kernel doc and other small fixes and
   improvements all over the code.

[ Merge fixup as per https://lore.kernel.org/all/YXAqZ%2FEszRisunQw@osiris/ ]

* tag 's390-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (63 commits)
  s390: make command line configurable
  s390: support command lines longer than 896 bytes
  s390/kexec_file: move kernel image size check
  s390/pci: add s390_iommu_aperture kernel parameter
  s390/spinlock: remove incorrect kernel doc indicator
  s390/string: use generic strlcpy
  s390/string: use generic strrchr
  s390/ap: function rework based on compiler warning
  s390/cio: make ccw_device_dma_* more robust
  s390/vfio-ap: s390/crypto: fix all kernel-doc warnings
  s390/hmcdrv: fix kernel doc comments
  s390/ap: new module option ap.useirq
  s390/cpumf: Allow multiple processes to access /dev/hwc
  s390/bitops: return true/false (not 1/0) from bool functions
  s390: add support for BEAR enhancement facility
  s390: introduce nospec_uses_trampoline()
  s390: rename last_break to pgm_last_break
  s390/ptrace: add last_break member to pt_regs
  s390/sclp: sort out physical vs virtual pointers usage
  s390/setup: convert start and end initrd pointers to virtual
  ...

1 files changed, 12 insertions, 0 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f0d6887e4bf9..0905d2cdb2d5 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4992,6 +4992,18 @@
 			an IOTLB flush. Default is lazy flushing before reuse,
 			which is faster.
 
+	s390_iommu_aperture=	[KNL,S390]
+			Specifies the size of the per device DMA address space
+			accessible through the DMA and IOMMU APIs as a decimal
+			factor of the size of main memory.
+			The default is 1 meaning that one can concurrently use
+			as many DMA addresses as physical memory is installed,
+			if supported by hardware, and thus map all of memory
+			once. With a value of 2 one can map all of memory twice
+			and so on. As a special case a factor of 0 imposes no
+			restrictions other than those given by hardware at the
+			cost of significant additional memory use for tables.
+
 	sa1100ir	[NET]
 			See drivers/net/irda/sa1100_ir.c.