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authorLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 14:48:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 14:48:06 -0700
commit0b707e572a1955b892dfcb32e7b573fab78767d9 (patch)
tree20ef1316e12005e71e6b5ae36eeebadaab7f862e /Documentation
parent0c5c62ddf88c34bc83b66e4ac9beb2bb0e1887d4 (diff)
parent622021cd6c560ce7aaaf7294a732177a30c9d65f (diff)
downloadlinux-0b707e572a1955b892dfcb32e7b573fab78767d9.tar.bz2
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 ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt12
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.