With no callers left of prandom_u32() and prandom_bytes(), as well as
get_random_int(), remove these deprecated wrappers, in favor of
get_random_u32() and get_random_bytes().
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Pull IPMI updates from Corey Minyard:
"Fix a bunch of little problems in IPMI
This is mostly just doc, config, and little tweaks. Nothing big, which
is why there was nothing for 6.0. There is one crash fix, but it's not
something that I think anyone is using yet"
* tag 'for-linus-6.1-1' of https://github.com/cminyard/linux-ipmi:
ipmi: Remove unused struct watcher_entry
ipmi: kcs: aspeed: Update port address comments
ipmi: Add __init/__exit annotations to module init/exit funcs
ipmi:ipmb: Don't call ipmi_unregister_smi() on a register failure
ipmi:ipmb: Fix a vague comment and a typo
dt-binding: ipmi: add fallback to npcm845 compatible
ipmi: Fix comment typo
char: ipmi: modify NPCM KCS configuration
dt-bindings: ipmi: Add npcm845 compatible
Pull tpm updates from Jarkko Sakkinen:
"Just a few bug fixes this time"
* tag 'tpmdd-next-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
selftest: tpm2: Add Client.__del__() to close /dev/tpm* handle
security/keys: Remove inconsistent __user annotation
char: move from strlcpy with unused retval to strscpy
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
Pull tty/serial driver updates from Greg KH:
"Here is the big set of TTY and Serial driver updates for 6.1-rc1.
Lots of cleanups in here, no real new functionality this time around,
with the diffstat being that we removed more lines than we added!
Included in here are:
- termios unification cleanups from Al Viro, it's nice to finally get
this work done
- tty serial transmit cleanups in various drivers in preparation for
more cleanup and unification in future releases (that work was not
ready for this release)
- n_gsm fixes and updates
- ktermios cleanups and code reductions
- dt bindings json conversions and updates for new devices
- some serial driver updates for new devices
- lots of other tiny cleanups and janitorial stuff. Full details in
the shortlog.
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (102 commits)
serial: cpm_uart: Don't request IRQ too early for console port
tty: serial: do unlock on a common path in altera_jtaguart_console_putc()
tty: serial: unify TX space reads under altera_jtaguart_tx_space()
tty: serial: use FIELD_GET() in lqasc_tx_ready()
tty: serial: extend lqasc_tx_ready() to lqasc_console_putchar()
tty: serial: allow pxa.c to be COMPILE_TESTed
serial: stm32: Fix unused-variable warning
tty: serial: atmel: Add COMMON_CLK dependency to SERIAL_ATMEL
serial: 8250: Fix restoring termios speed after suspend
serial: Deassert Transmit Enable on probe in driver-specific way
serial: 8250_dma: Convert to use uart_xmit_advance()
serial: 8250_omap: Convert to use uart_xmit_advance()
MAINTAINERS: Solve warning regarding inexistent atmel-usart binding
serial: stm32: Deassert Transmit Enable on ->rs485_config()
serial: ar933x: Deassert Transmit Enable on ->rs485_config()
tty: serial: atmel: Use FIELD_PREP/FIELD_GET
tty: serial: atmel: Make the driver aware of the existence of GCLK
tty: serial: atmel: Only divide Clock Divisor if the IP is USART
tty: serial: atmel: Separate mode clearing between UART and USART
dt-bindings: serial: atmel,at91-usart: Add gclk as a possible USART clock
...
The commit that added the new get_random_{u8,u16}() functions neglected
to update the code that clears the batches when bringing up a new CPU.
It also forgot a few comments and helper defines, so add those in too.
Fixes: 585cd5fe9f ("random: add 8-bit and 16-bit batches")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Remove extra whitespace and add a missing word to a sentence describing
get_random_bytes().
Signed-off-by: William Zijl <postmaster@gusted.xyz>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Counterintuitively, mod_timer(..., jiffies + 1) will cause the timer to
fire not in the next jiffy, but in two jiffies. The way to cause
the timer to fire in the next jiffy is with mod_timer(..., jiffies).
Doing so then lets us bump the upper bound back up again.
Fixes: 50ee7529ec ("random: try to actively add entropy rather than passively wait for it")
Fixes: 829d680e82 ("random: cap jitter samples per bit to factor of HZ")
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Start the hwrng kthread even if the hwrng source has a quality setting
of zero. Then, every crng reseed interval, one batch of data from this
zero-quality hwrng source will be mixed into the CRNG pool.
This patch is based on the assumption that data from a hwrng source
will not actively harm the CRNG state. Instead, many hwrng sources
(such as TPM devices), even though they are assigend a quality level of
zero, actually provide some entropy, which is good enough to mix into
the CRNG pool every once in a while.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
There are numerous places in the kernel that would be sped up by having
smaller batches. Currently those callsites do `get_random_u32() & 0xff`
or similar. Since these are pretty spread out, and will require patches
to multiple different trees, let's get ahead of the curve and lay the
foundation for `get_random_u8()` and `get_random_u16()`, so that it's
then possible to start submitting conversion patches leisurely.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Rather than going through the current-> indirection for utsname, at this
point in boot, init_utsname()==utsname(), so just use it directly that
way. Additionally, init_utsname() appears to be available nearly always,
so move it into random_init_early().
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The full RNG initialization relies on some timestamps, made possible
with initialization functions like time_init() and timekeeping_init().
However, these are only available rather late in initialization.
Meanwhile, other things, such as memory allocator functions, make use of
the RNG much earlier.
So split RNG initialization into two phases. We can provide arch
randomness very early on, and then later, after timekeeping and such are
available, initialize the rest.
This ensures that, for example, slabs are properly randomized if RDRAND
is available. Without this, CONFIG_SLAB_FREELIST_RANDOM=y loses a degree
of its security, because its random seed is potentially deterministic,
since it hasn't yet incorporated RDRAND. It also makes it possible to
use a better seed in kfence, which currently relies on only the cycle
counter.
Another positive consequence is that on systems with RDRAND, running
with CONFIG_WARN_ALL_UNSEEDED_RANDOM=y results in no warnings at all.
One subtle side effect of this change is that on systems with no RDRAND,
RDTSC is now only queried by random_init() once, committing the moment
of the function call, instead of multiple times as before. This is
intentional, as the multiple RDTSCs in a loop before weren't
accomplishing very much, with jitter being better provided by
try_to_generate_entropy(). Plus, filling blocks with RDTSC is still
being done in extract_entropy(), which is necessarily called before
random bytes are served anyway.
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Previously, the fast pool was dumped into the main pool periodically in
the fast pool's hard IRQ handler. This worked fine and there weren't
problems with it, until RT came around. Since RT converts spinlocks into
sleeping locks, problems cropped up. Rather than switching to raw
spinlocks, the RT developers preferred we make the transformation from
originally doing:
do_some_stuff()
spin_lock()
do_some_other_stuff()
spin_unlock()
to doing:
do_some_stuff()
queue_work_on(some_other_stuff_worker)
This is an ordinary pattern done all over the kernel. However, Sherry
noticed a 10% performance regression in qperf TCP over a 40gbps
InfiniBand card. Quoting her message:
> MT27500 Family [ConnectX-3] cards:
> Infiniband device 'mlx4_0' port 1 status:
> default gid: fe80:0000:0000:0000:0010:e000:0178:9eb1
> base lid: 0x6
> sm lid: 0x1
> state: 4: ACTIVE
> phys state: 5: LinkUp
> rate: 40 Gb/sec (4X QDR)
> link_layer: InfiniBand
>
> Cards are configured with IP addresses on private subnet for IPoIB
> performance testing.
> Regression identified in this bug is in TCP latency in this stack as reported
> by qperf tcp_lat metric:
>
> We have one system listen as a qperf server:
> [root@yourQperfServer ~]# qperf
>
> Have the other system connect to qperf server as a client (in this
> case, it’s X7 server with Mellanox card):
> [root@yourQperfClient ~]# numactl -m0 -N0 qperf 20.20.20.101 -v -uu -ub --time 60 --wait_server 20 -oo msg_size:4K:1024K:*2 tcp_lat
Rather than incur the scheduling latency from queue_work_on, we can
instead switch to running on the next timer tick, on the same core. This
also batches things a bit more -- once per jiffy -- which is okay now
that mix_interrupt_randomness() can credit multiple bits at once.
Reported-by: Sherry Yang <sherry.yang@oracle.com>
Tested-by: Paul Webb <paul.x.webb@oracle.com>
Cc: Sherry Yang <sherry.yang@oracle.com>
Cc: Phillip Goerl <phillip.goerl@oracle.com>
Cc: Jack Vogel <jack.vogel@oracle.com>
Cc: Nicky Veitch <nicky.veitch@oracle.com>
Cc: Colm Harrington <colm.harrington@oracle.com>
Cc: Ramanan Govindarajan <ramanan.govindarajan@oracle.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: stable@vger.kernel.org
Fixes: 58340f8e95 ("random: defer fast pool mixing to worker")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
In order to avoid reading and dirtying two cache lines on every IRQ,
move the work_struct to the bottom of the fast_pool struct. add_
interrupt_randomness() always touches .pool and .count, which are
currently split, because .mix pushes everything down. Instead, move .mix
to the bottom, so that .pool and .count are always in the first cache
line, since .mix is only accessed when the pool is full.
Fixes: 58340f8e95 ("random: defer fast pool mixing to worker")
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Since the most that's mixed into the pool is sizeof(long)*2, don't
credit more than that many bytes of entropy.
Fixes: e3e33fc2ea ("random: do not use input pool from hard IRQs")
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
If a hwrng source does not provide an entropy estimate, it currently
does not contribute at all to the CRNG. In order to help fix this, in
case add_hwgenerator_randomness() is called with the entropy parameter
set to zero, go to sleep until one reseed interval has passed.
While the hwrng thread currently only runs under conditions where this
is non-zero, this change is not harmful and prepares for future updates
to the hwrng core.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Mix in randomness from hw-rng sources more frequently during early
boot, approximately once for every rng reseed.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Prior to 5.6, when /dev/random was opened with O_NONBLOCK, it would
return -EAGAIN if there was no entropy. When the pools were unified in
5.6, this was lost. The post 5.6 behavior of blocking until the pool is
initialized, and ignoring O_NONBLOCK in the process, went unnoticed,
with no reports about the regression received for two and a half years.
However, eventually this indeed did break somebody's userspace.
So we restore the old behavior, by returning -EAGAIN if the pool is not
initialized. Unlike the old /dev/random, this can only occur during
early boot, after which it never blocks again.
In order to make this O_NONBLOCK behavior consistent with other
expectations, also respect users reading with preadv2(RWF_NOWAIT) and
similar.
Fixes: 30c08efec8 ("random: make /dev/random be almost like /dev/urandom")
Reported-by: Guozihua <guozihua@huawei.com>
Reported-by: Zhongguohua <zhongguohua1@huawei.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Remove AST_usrGuide_KCS.pdf as it is no longer maintained.
Add more descriptions as the driver now supports the I/O
address configurations for both the KCS Data and Cmd/Status
interface registers.
Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Message-Id: <20220920020333.601-1-chiawei_wang@aspeedtech.com>
[I don't like removing documentation, but the document in question
was a personal note by an employee and nothing official and not
necessarily guaranteed to be accurate in the future. So go
ahead and remove it.]
Signed-off-by: Corey Minyard <cminyard@mvista.com>
