linux/drivers/char
Linus Torvalds 8adc0486f3 Random number generator updates for Linux 6.1-rc1.
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Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:

 - Huawei reported that when they updated their kernel from 4.4 to
   something much newer, some userspace code they had broke, the culprit
   being the accidental removal of O_NONBLOCK from /dev/random way back
   in 5.6. It's been gone for over 2 years now and this is the first
   we've heard of it, but userspace breakage is userspace breakage, so
   O_NONBLOCK is now back.

 - Use randomness from hardware RNGs much more often during early boot,
   at the same interval that crng reseeds are done, from Dominik.

 - A semantic change in hardware RNG throttling, so that the hwrng
   framework can properly feed random.c with randomness from hardware
   RNGs that aren't specifically marked as creditable.

   A related patch coming to you via Herbert's hwrng tree depends on
   this one, not to compile, but just to function properly, so you may
   want to merge this PULL before that one.

 - A fix to clamp credited bits from the interrupts pool to the size of
   the pool sample. This is mainly just a theoretical fix, as it'd be
   pretty hard to exceed it in practice.

 - Oracle reported that InfiniBand TCP latency regressed by around
   10-15% after a change a few cycles ago made at the request of the RT
   folks, in which we hoisted a somewhat rare operation (1 in 1024
   times) out of the hard IRQ handler and into a workqueue, a pretty
   common and boring pattern.

   It turns out, though, that scheduling a worker from there has
   overhead of its own, whereas scheduling a timer on that same CPU for
   the next jiffy amortizes better and doesn't incur the same overhead.

   I also eliminated a cache miss by moving the work_struct (and
   subsequently, the timer_list) to below a critical cache line, so that
   the more critical members that are accessed on every hard IRQ aren't
   split between two cache lines.

 - The boot-time initialization of the RNG has been split into two
   approximate phases: what we can accomplish before timekeeping is
   possible and what we can accomplish after.

   This winds up being useful so that we can use RDRAND to seed the RNG
   before CONFIG_SLAB_FREELIST_RANDOM=y systems initialize slabs, in
   addition to other early uses of randomness. The effect is that
   systems with RDRAND (or a bootloader seed) will never see any
   warnings at all when setting CONFIG_WARN_ALL_UNSEEDED_RANDOM=y. And
   kfence benefits from getting a better seed of its own.

 - Small systems without much entropy sometimes wind up putting some
   truncated serial number read from flash into hostname, so contribute
   utsname changes to the RNG, without crediting.

 - Add smaller batches to serve requests for smaller integers, and make
   use of them when people ask for random numbers bounded by a given
   compile-time constant. This has positive effects all over the tree,
   most notably in networking and kfence.

 - The original jitter algorithm intended (I believe) to schedule the
   timer for the next jiffy, not the next-next jiffy, yet it used
   mod_timer(jiffies + 1), which will fire on the next-next jiffy,
   instead of what I believe was intended, mod_timer(jiffies), which
   will fire on the next jiffy. So fix that.

 - Fix a comment typo, from William.

* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  random: clear new batches when bringing new CPUs online
  random: fix typos in get_random_bytes() comment
  random: schedule jitter credit for next jiffy, not in two jiffies
  prandom: make use of smaller types in prandom_u32_max
  random: add 8-bit and 16-bit batches
  utsname: contribute changes to RNG
  random: use init_utsname() instead of utsname()
  kfence: use better stack hash seed
  random: split initialization into early step and later step
  random: use expired timer rather than wq for mixing fast pool
  random: avoid reading two cache lines on irq randomness
  random: clamp credited irq bits to maximum mixed
  random: throttle hwrng writes if no entropy is credited
  random: use hwgenerator randomness more frequently at early boot
  random: restore O_NONBLOCK support
2022-10-10 10:41:21 -07:00
..
agp IOMMU Updates for Linux v5.20/v6.0: 2022-08-06 10:42:38 -07:00
hw_random s390 updates for 5.20 merge window 2022-08-06 17:05:21 -07:00
ipmi i2c: Make remove callback return void 2022-08-16 12:46:26 +02:00
mwave char/mwave: Adjust io port register size 2021-12-03 14:27:06 +01:00
pcmcia tty: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
tpm i2c: Make remove callback return void 2022-08-16 12:46:26 +02:00
xilinx_hwicap xilinx_hwicap: cleanup comments 2022-02-25 12:08:57 +01:00
xillybus char: xillybus: fix a refcount leak in cleanup_dev() 2022-04-24 17:30:45 +02:00
adi.c char: sparc64: Add privileged ADI driver 2018-06-05 11:24:55 -07:00
apm-emulation.c apm-emulation: drop unexpected word "the" in the comments 2022-06-27 16:15:27 +02:00
applicom.c applicom: unneed to initialise statics to 0 2021-12-21 10:14:08 +01:00
applicom.h
bsr.c powerpc/BSR: Make use of the helper macro LIST_HEAD() 2022-02-25 12:10:15 +01:00
ds1620.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
dsp56k.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
dtlk.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
hangcheck-timer.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 405 2019-06-05 17:37:13 +02:00
hpet.c hpet: remove unused writeq/readq function definitions 2022-02-04 16:45:39 +01:00
Kconfig Char / Misc driver changes for 6.0-rc1 2022-08-04 11:05:48 -07:00
lp.c char: lp: remove redundant initialization of err 2022-06-10 15:29:50 +02:00
Makefile char: remove VR41XX related char driver 2022-07-28 16:12:33 +02:00
mem.c random: restore O_NONBLOCK support 2022-09-23 12:27:57 +02:00
misc.c char: misc: remove usage of list iterator past the loop body 2022-04-24 17:15:12 +02:00
mspec.c char: mspec: Use kvzalloc() in mspec_mmap() 2020-08-28 12:10:04 +02:00
nsc_gpio.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
nvram.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
nwbutton.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
nwbutton.h misc: cleanup minor number definitions in c file into miscdevice.h 2020-03-18 12:27:03 +01:00
nwflash.c misc: move FLASH_MINOR into miscdevice.h and fix conflicts 2020-03-18 12:27:04 +01:00
pc8736x_gpio.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
powernv-op-panel.c powerpc/powernv: Fix fall-through warning for Clang 2021-07-13 19:21:41 -05:00
ppdev.c ppdev: Distribute switch variables for initialization 2020-02-23 20:28:12 +01:00
ps3flash.c powerpc/ps3: make system bus's remove and shutdown callbacks return void 2020-12-04 01:01:22 +11:00
random.c random: clear new batches when bringing new CPUs online 2022-10-06 09:35:55 -06:00
scx200_gpio.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
sonypi.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
tlclk.c drivers: char: tlclk.c: Avoid data race between init and interrupt handler 2020-04-23 16:55:24 +02:00
toshiba.c module: remove never implemented MODULE_SUPPORTED_DEVICE 2021-03-17 13:16:18 -07:00
ttyprintk.c char: ttyprintk: register console 2022-04-22 16:24:47 +02:00
uv_mmtimer.c
virtio_console.c Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00