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A potential deadlock was reported with the config file at
https://web.archive.org/web/20240522052129/https://0x0.st/XPN_.txt
In this particular configuration, the deadlock doesn't exist because
the warning triggered at a point before modules were even available.
However, the deadlock can be real because any module loaded would
invoke async_synchronize_full.
The issue is spurious for software crypto algorithms which aren't
themselves involved in async probing. However, it would be hard to
avoid for a PCI crypto driver using async probing.
In this particular call trace, the problem is easily avoided because
the only reason the module is being requested during probing is the
add_early_randomness call in the hwrng core. This feature is
vestigial since there is now a kernel thread dedicated to doing
exactly this.
So remove add_early_randomness as it is no longer needed.
Reported-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reported-by: Eric Biggers <ebiggers@kernel.org>
Fixes: 1b6d7f9eb150 ("tpm: add session encryption protection to tpm2_get_random()")
Link: https://lore.kernel.org/r/119dc5ed-f159-41be-9dda-1a056f29888d@notapiano/
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Per filesystems/sysfs.rst, show() should only use sysfs_emit()
or sysfs_emit_at() when formatting the value to be returned to user space.
coccinelle complains that there are still a couple of functions that use
snprintf(). Convert them to sysfs_emit().
sprintf() will be converted as weel if they have.
Generally, this patch is generated by
make coccicheck M=<path/to/file> MODE=patch \
COCCI=scripts/coccinelle/api/device_attr_show.cocci
No functional change intended
CC: Olivia Mackall <olivia@selenic.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: linux-crypto@vger.kernel.org
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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There is a dead-lock in the hwrng device read path. This triggers
when the user reads from /dev/hwrng into memory also mmap-ed from
/dev/hwrng. The resulting page fault triggers a recursive read
which then dead-locks.
Fix this by using a stack buffer when calling copy_to_user.
Reported-by: Edward Adam Davis <eadavis@qq.com>
Reported-by: syzbot+c52ab18308964d248092@syzkaller.appspotmail.com
Fixes: 9996508b3353 ("hwrng: core - Replace u32 in driver API with byte array")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The last RCU stall fix caused a massive throughput regression of the
hwrng on Raspberry Pi 0 - 3. hwrng_msleep doesn't sleep precisely enough
and usleep_range doesn't allow scheduling. So try to restore the
best possible throughput by introducing hwrng_yield which interruptable
sleeps for one jiffy.
Some performance measurements on Raspberry Pi 3B+ (arm64/defconfig):
sudo dd if=/dev/hwrng of=/dev/null count=1 bs=10000
cpu_relax ~138025 Bytes / sec
hwrng_msleep(1000) ~13 Bytes / sec
hwrng_yield ~2510 Bytes / sec
Fixes: 96cb9d055445 ("hwrng: bcm2835 - use hwrng_msleep() instead of cpu_relax()")
Link: https://lore.kernel.org/linux-arm-kernel/bc97ece5-44a3-4c4e-77da-2db3eb66b128@gmx.net/
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Remove duplicated include of linux/random.h. Resolves checkincludes
message. And adjust includes in alphabetical order.
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
"API:
- Optimise away self-test overhead when they are disabled
- Support symmetric encryption via keyring keys in af_alg
- Flip hwrng default_quality, the default is now maximum entropy
Algorithms:
- Add library version of aesgcm
- CFI fixes for assembly code
- Add arm/arm64 accelerated versions of sm3/sm4
Drivers:
- Remove assumption on arm64 that kmalloc is DMA-aligned
- Fix selftest failures in rockchip
- Add support for RK3328/RK3399 in rockchip
- Add deflate support in qat
- Merge ux500 into stm32
- Add support for TEE for PCI ID 0x14CA in ccp
- Add mt7986 support in mtk
- Add MaxLinear platform support in inside-secure
- Add NPCM8XX support in npcm"
* tag 'v6.2-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (184 commits)
crypto: ux500/cryp - delete driver
crypto: stm32/cryp - enable for use with Ux500
crypto: stm32 - enable drivers to be used on Ux500
dt-bindings: crypto: Let STM32 define Ux500 CRYP
hwrng: geode - Fix PCI device refcount leak
hwrng: amd - Fix PCI device refcount leak
crypto: qce - Set DMA alignment explicitly
crypto: octeontx2 - Set DMA alignment explicitly
crypto: octeontx - Set DMA alignment explicitly
crypto: keembay - Set DMA alignment explicitly
crypto: safexcel - Set DMA alignment explicitly
crypto: hisilicon/hpre - Set DMA alignment explicitly
crypto: chelsio - Set DMA alignment explicitly
crypto: ccree - Set DMA alignment explicitly
crypto: ccp - Set DMA alignment explicitly
crypto: cavium - Set DMA alignment explicitly
crypto: img-hash - Fix variable dereferenced before check 'hdev->req'
crypto: arm64/ghash-ce - use frame_push/pop macros consistently
crypto: arm64/crct10dif - use frame_push/pop macros consistently
crypto: arm64/aes-modes - use frame_push/pop macros consistently
...
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Most hw_random devices return entropy which is assumed to be of full
quality, but driver authors don't bother setting the quality knob. Some
hw_random devices return less than full quality entropy, and then driver
authors set the quality knob. Therefore, the entropy crediting should be
opt-out rather than opt-in per-driver, to reflect the actual reality on
the ground.
For example, the two Raspberry Pi RNG drivers produce full entropy
randomness, and both EDK2 and U-Boot's drivers for these treat them as
such. The result is that EFI then uses these numbers and passes the to
Linux, and Linux credits them as boot, thereby initializing the RNG.
Yet, in Linux, the quality knob was never set to anything, and so on the
chance that Linux is booted without EFI, nothing is ever credited.
That's annoying.
The same pattern appears to repeat itself throughout various drivers. In
fact, very very few drivers have bothered setting quality=1024.
Looking at the git history of existing drivers and corresponding mailing
list discussion, this conclusion tracks. There's been a decent amount of
discussion about drivers that set quality < 1024 -- somebody read and
interepreted a datasheet, or made some back of the envelope calculation
somehow. But there's been very little, if any, discussion about most
drivers where the quality is just set to 1024 or unset (or set to 1000
when the authors misunderstood the API and assumed it was base-10 rather
than base-2); in both cases the intent was fairly clear of, "this is a
hardware random device; it's fine."
So let's invert this logic. A hw_random struct's quality knob now
controls the maximum quality a driver can produce, or 0 to specify 1024.
Then, the module-wide switch called "default_quality" is changed to
represent the maximum quality of any driver. By default it's 1024, and
the quality of any particular driver is then given by:
min(default_quality, rng->quality ?: 1024);
This way, the user can still turn this off for weird reasons (and we can
replace whatever driver-specific disabling hacks existed in the past),
yet we get proper crediting for relevant RNGs.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Rather than calling add_device_randomness(), the add_early_randomness()
function should use add_hwgenerator_randomness(), so that the early
entropy can be potentially credited, which allows for the RNG to
initialize earlier without having to wait for the kthread to come up.
This requires some minor API refactoring, by adding a `sleep_after`
parameter to add_hwgenerator_randomness(), so that we don't hit a
blocking sleep from add_early_randomness().
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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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>
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There are two deadlock scenarios that need addressing, which cause
problems when the computer goes to sleep, the interface is set down, and
hwrng_unregister() is called. When the deadlock is hit, sleep is delayed
for tens of seconds, causing it to fail. These scenarios are:
1) The hwrng kthread can't be stopped while it's sleeping, because it
uses msleep_interruptible() which does not react to kthread_stop.
2) A normal user thread can't be interrupted by hwrng_unregister() while
it's sleeping, because hwrng_unregister() is called from elsewhere.
We solve both issues by add a completion object called dying that
fulfils waiters once we have started the process in hwrng_unregister.
At the same time, we should cleanup a common and useless dmesg splat
in the same area.
Cc: <stable@vger.kernel.org>
Reported-by: Gregory Erwin <gregerwin256@gmail.com>
Fixes: fcd09c90c3c5 ("ath9k: use hw_random API instead of directly dumping into random.c")
Link: https://lore.kernel.org/all/CAO+Okf6ZJC5-nTE_EJUGQtd8JiCkiEHytGgDsFGTEjs0c00giw@mail.gmail.com/
Link: https://lore.kernel.org/lkml/CAO+Okf5k+C+SE6pMVfPf-d8MfVPVq4PO7EY8Hys_DVXtent3HA@mail.gmail.com/
Link: https://bugs.archlinux.org/task/75138
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
"API:
- hwrng core now credits for low-quality RNG devices.
Algorithms:
- Optimisations for neon aes on arm/arm64.
- Add accelerated crc32_be on arm64.
- Add ffdheXYZ(dh) templates.
- Disallow hmac keys < 112 bits in FIPS mode.
- Add AVX assembly implementation for sm3 on x86.
Drivers:
- Add missing local_bh_disable calls for crypto_engine callback.
- Ensure BH is disabled in crypto_engine callback path.
- Fix zero length DMA mappings in ccree.
- Add synchronization between mailbox accesses in octeontx2.
- Add Xilinx SHA3 driver.
- Add support for the TDES IP available on sama7g5 SoC in atmel"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (137 commits)
crypto: xilinx - Turn SHA into a tristate and allow COMPILE_TEST
MAINTAINERS: update HPRE/SEC2/TRNG driver maintainers list
crypto: dh - Remove the unused function dh_safe_prime_dh_alg()
hwrng: nomadik - Change clk_disable to clk_disable_unprepare
crypto: arm64 - cleanup comments
crypto: qat - fix initialization of pfvf rts_map_msg structures
crypto: qat - fix initialization of pfvf cap_msg structures
crypto: qat - remove unneeded assignment
crypto: qat - disable registration of algorithms
crypto: hisilicon/qm - fix memset during queues clearing
crypto: xilinx: prevent probing on non-xilinx hardware
crypto: marvell/octeontx - Use swap() instead of open coding it
crypto: ccree - Fix use after free in cc_cipher_exit()
crypto: ccp - ccp_dmaengine_unregister release dma channels
crypto: octeontx2 - fix missing unlock
hwrng: cavium - fix NULL but dereferenced coccicheck error
crypto: cavium/nitrox - don't cast parameter in bit operations
crypto: vmx - add missing dependencies
MAINTAINERS: Add maintainer for Xilinx ZynqMP SHA3 driver
crypto: xilinx - Add Xilinx SHA3 driver
...
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add_hwgenerator_randomness() is a function implemented and documented
inside of random.c. It is the way that hardware RNGs push data into it.
Therefore, it should be declared in random.h. Otherwise sparse complains
with:
random.c:1137:6: warning: symbol 'add_hwgenerator_randomness' was not declared. Should it be static?
The alternative would be to include hw_random.h into random.c, but that
wouldn't really be good for anything except slowing down compile time.
Cc: Matt Mackall <mpm@selenic.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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The rng_quality sysfs attribute returns the quality setting for the
currently active hw_random device, in entropy bits per 1024 bits of
input. Storing a value between 0 and 1024 to this file updates this
estimate accordingly.
Based on the updates to the quality setting, the rngd kernel thread
may be stopped (if no hw_random device is trusted to return entropy),
may be started (if the quality setting is increased from zero), or
may use a different hw_random source (if that has higher quality
output).
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>
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The current_quality variable exposed as a module parameter is
fundamentally broken: If it is set at boot time, it is overwritten once
the first hw rng device is loaded; if it is set at runtime, it is
without effect if the hw rng device had its quality value set to 0 (and
no default_quality was set); and if a new rng is selected, it gets
overwritten. Therefore, mark it as obsolete, and replace it by the
per-rng quality setting.
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>
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Extract the start/stop logic for the in-kernel rngd thread to
a separate function.
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>
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There is no real reason why this list needs to be kept ordered by
the driver-provided quality value -- a value which is set only by
a handful of hw_random devices anyway.
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>
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In case the entropy quality is low, there may be less than one bit to
credit in the call to add_hwgenerator_randomness(): The number of bytes
returned by rng_get_data() multiplied by the current quality (in entropy
bits per 1024 bits of input) must be larger than 128 to credit at least
one bit. However, imx-rngc.c sets the quality to 19, but may return less
than 32 bytes; hid_u2fzero.c sets the quality to 1; and users may override
the quality setting manually.
In case there is less than one bit to credit, keep track of it and add
that credit to the next iteration.
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>
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For two reasons, current_quality may become zero within the rngd
kernel thread: (1) The user lowers current_quality to 0 by writing
to the sysfs module parameter file (note that increasing the quality
from zero is without effect at the moment), or (2) there are two or
more hwrng devices registered, and those which provide quality>0 are
unregistered, but one with quality==0 remains.
If current_quality is 0, the randomness is not trusted and cannot help
to increase the entropy count. That will lead to continuous calls to
the hwrngd thread and continuous stirring of the input pool with
untrusted bits.
Cc: Matt Mackall <mpm@selenic.com>
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>
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In case the user-specified rng device is not working, it is not used;
therefore cur_rng_set_by_user must not be set to 1.
Cc: Matt Mackall <mpm@selenic.com>
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>
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Using rng_buffer in add_early_randomness() may race with rng_dev_read().
Use rng_fillbuf instead, as it is otherwise only used within the kernel
by hwrng_fillfn() and therefore never exposed to userspace.
Cc: Matt Mackall <mpm@selenic.com>
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>
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According to <linux/hw_random.h>, the @max parameter of the ->read
callback "is a multiple of 4 and >= 32 bytes". That promise was not
kept by add_early_randomness(), which only asked for 16 bytes. As
rng_buffer_size() is at least 32, we can simply ask for 32 bytes.
Cc: Matt Mackall <mpm@selenic.com>
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>
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hw-random device drivers depend on the hw-random core being
initialized. Make this ordering explicit, also for the case
these drivers are built-in. As the core itself depends on
misc_register() which is set up at subsys_initcall time,
advance the initialization of the core (only) to the
fs_initcall() level.
Cc: Matt Mackall <mpm@selenic.com>
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>
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Use DEVICE_ATTR_RW()/DEVICE_ATTR_RO() helper instead of
plain DEVICE_ATTR, which makes the code a bit shorter and
easier to read.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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'err' will be assigned later and cleanup the redundant initialization.
Cc: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Fix the following coccicheck warning:
drivers/char/hw_random/core.c:399:8-16: WARNING: use scnprintf or sprintf.
Signed-off-by: Zihao Tang <tangzihao1@hisilicon.com>
Signed-off-by: Jay Fang <f.fangjian@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The variable ret is being initialized with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Pull crypto updates from Herbert Xu:
"API:
- Add library interfaces of certain crypto algorithms for WireGuard
- Remove the obsolete ablkcipher and blkcipher interfaces
- Move add_early_randomness() out of rng_mutex
Algorithms:
- Add blake2b shash algorithm
- Add blake2s shash algorithm
- Add curve25519 kpp algorithm
- Implement 4 way interleave in arm64/gcm-ce
- Implement ciphertext stealing in powerpc/spe-xts
- Add Eric Biggers's scalar accelerated ChaCha code for ARM
- Add accelerated 32r2 code from Zinc for MIPS
- Add OpenSSL/CRYPTOGRAMS poly1305 implementation for ARM and MIPS
Drivers:
- Fix entropy reading failures in ks-sa
- Add support for sam9x60 in atmel
- Add crypto accelerator for amlogic GXL
- Add sun8i-ce Crypto Engine
- Add sun8i-ss cryptographic offloader
- Add a host of algorithms to inside-secure
- Add NPCM RNG driver
- add HiSilicon HPRE accelerator
- Add HiSilicon TRNG driver"
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (285 commits)
crypto: vmx - Avoid weird build failures
crypto: lib/chacha20poly1305 - use chacha20_crypt()
crypto: x86/chacha - only unregister algorithms if registered
crypto: chacha_generic - remove unnecessary setkey() functions
crypto: amlogic - enable working on big endian kernel
crypto: sun8i-ce - enable working on big endian
crypto: mips/chacha - select CRYPTO_SKCIPHER, not CRYPTO_BLKCIPHER
hwrng: ks-sa - Enable COMPILE_TEST
crypto: essiv - remove redundant null pointer check before kfree
crypto: atmel-aes - Change data type for "lastc" buffer
crypto: atmel-tdes - Set the IV after {en,de}crypt
crypto: sun4i-ss - fix big endian issues
crypto: sun4i-ss - hide the Invalid keylen message
crypto: sun4i-ss - use crypto_ahash_digestsize
crypto: sun4i-ss - remove dependency on not 64BIT
crypto: sun4i-ss - Fix 64-bit size_t warnings on sun4i-ss-hash.c
MAINTAINERS: Add maintainer for HiSilicon SEC V2 driver
crypto: hisilicon - add DebugFS for HiSilicon SEC
Documentation: add DebugFS doc for HiSilicon SEC
crypto: hisilicon - add SRIOV for HiSilicon SEC
...
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This reverts commit 03a3bb7ae631 ("hwrng: core - Freeze khwrng
thread during suspend"), ff296293b353 ("random: Support freezable
kthreads in add_hwgenerator_randomness()") and 59b569480dc8 ("random:
Use wait_event_freezable() in add_hwgenerator_randomness()").
These patches introduced regressions and we need more time to
get them ready for mainline.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Commit daae28debcb0 has moved add_early_randomness() out of the
rng_mutex and tries to protect the reference of the new rng device
by incrementing the reference counter.
But in hwrng_register(), the function can be called with a new device
that is not set as the current_rng device and the reference has not been
initialized. This patch fixes the problem by not using the reference
counter when the device is not the current one: the reference counter
is only meaningful in the case of the current rng device and a device
is not used if it is not the current one (except in hwrng_register())
The problem has been reported by Marek Szyprowski on ARM 32bit
Exynos5420-based Chromebook Peach-Pit board:
WARNING: CPU: 3 PID: 1 at lib/refcount.c:156 hwrng_register+0x13c/0x1b4
refcount_t: increment on 0; use-after-free.
Modules linked in:
CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc1-00061-gdaae28debcb0
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[<c01124c8>] (unwind_backtrace) from [<c010dfb8>] (show_stack+0x10/0x14)
[<c010dfb8>] (show_stack) from [<c0ae86d8>] (dump_stack+0xa8/0xd4)
[<c0ae86d8>] (dump_stack) from [<c0127428>] (__warn+0xf4/0x10c)
[<c0127428>] (__warn) from [<c01274b4>] (warn_slowpath_fmt+0x74/0xb8)
[<c01274b4>] (warn_slowpath_fmt) from [<c054729c>] (hwrng_register+0x13c/0x1b4)
[<c054729c>] (hwrng_register) from [<c0547e54>] (tpm_chip_register+0xc4/0x274)
...
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: daae28debcb0 ("hwrng: core - move add_early_randomness() out of rng_mutex")
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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add_early_randomness() is called every time a new rng backend is added
and every time it is set as the current rng provider.
add_early_randomness() is called from functions locking rng_mutex,
and if it hangs all the hw_random framework hangs: we can't read sysfs,
add or remove a backend.
This patch move add_early_randomness() out of the rng_mutex zone.
It only needs the reading_mutex.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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add_early_randomness() is called by hwrng_register() when the
hardware is added. If this hardware and its module are present
at boot, and if there is no data available the boot hangs until
data are available and can't be interrupted.
For instance, in the case of virtio-rng, in some cases the host can be
not able to provide enough entropy for all the guests.
We can have two easy ways to reproduce the problem but they rely on
misconfiguration of the hypervisor or the egd daemon:
- if virtio-rng device is configured to connect to the egd daemon of the
host but when the virtio-rng driver asks for data the daemon is not
connected,
- if virtio-rng device is configured to connect to the egd daemon of the
host but the egd daemon doesn't provide data.
The guest kernel will hang at boot until the virtio-rng driver provides
enough data.
To avoid that, call rng_get_data() in non-blocking mode (wait=0)
from add_early_randomness().
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Fixes: d9e797261933 ("hwrng: add randomness to system from rng...")
Cc: <stable@vger.kernel.org>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The hwrng_fill() function can run while devices are suspending and
resuming. If the hwrng is behind a bus such as i2c or SPI and that bus
is suspended, the hwrng may hang the bus while attempting to add some
randomness. It's been observed on ChromeOS devices with suspend-to-idle
(s2idle) and an i2c based hwrng that this kthread may run and ask the
hwrng device for randomness before the i2c bus has been resumed.
Let's make this kthread freezable so that we don't try to touch the
hwrng during suspend/resume. This ensures that we can't cause the hwrng
backing driver to get into a bad state because the device is guaranteed
to be resumed before the hwrng kthread is thawed.
Cc: Andrey Pronin <apronin@chromium.org>
Cc: Duncan Laurie <dlaurie@chromium.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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There are lots of documents that belong to the admin-guide but
are on random places (most under Documentation root dir).
Move them to the admin guide.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
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quality field is currently documented as being 'per mill'. In fact the
math involved is:
add_hwgenerator_randomness((void *)rng_fillbuf, rc,
rc * current_quality * 8 >> 10);
thus the actual definition is "bits of entropy per 1024 bits of input".
The current documentation seems to have confused multiple people
in the past, let's fix the documentation to match code.
An alternative is to change core to match driver expectations, replacing
rc * current_quality * 8 >> 10
with
rc * current_quality / 1000
but that has performance costs, so probably isn't a good option.
Fixes: 0f734e6e768 ("hwrng: add per-device entropy derating")
Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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enable_best_rng() is used in hwrng_unregister() to switch away from the
currently active RNG, if that is the one currently being removed.
However enable_best_rng() might fail, if the next RNG's init routine
fails. In that case enable_best_rng() will return an error code and
the currently active RNG will remain active.
After unregistering this might lead to crashes due to use-after-free.
Fix this by dropping the currently active RNG, if enable_best_rng()
failed. This will result in no RNG to be active, if the next-best
one failed to initialize.
This problem was introduced by 142a27f0a731ddcf467546960a5585970ca98e21
Fixes: 142a27f0a731 ("hwrng: core - Reset user selected rng by...")
Reported-by: Wirz <spam@lukas-wirz.de>
Tested-by: Wirz <spam@lukas-wirz.de>
Signed-off-by: Michael Büsch <m@bues.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Commit 142a27f0a731 added support for a "best" RNG, and in doing so
introduced a hang from rmmod/modprobe -r when the last RNG on the list
was unloaded.
When the hwrng list is depleted, return the global variables to their
original state and decrement all references to the object.
Fixes: 142a27f0a731 ("hwrng: core - Reset user selected rng by writing "" to rng_current")
Signed-off-by: Gary R Hook <gary.hook@amd.com>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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User is able to select a chosen rng by writing its name to rng_current
but there is no way to reset it without unbinding the rng. Let user
write "" to rng_current and delesect the chosen rng.
Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
reviewed-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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pr_err() messages should terminated with a new-line to avoid
other messages being concatenated onto the end.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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When a user chooses a rng source via sysfs attribute
this rng should be sticky, even when other sources
with better quality to register. This patch introduces
a simple way to remember the user's choice. This is
reflected by a new sysfs attribute file 'rng_selected'
which shows if the current rng has been chosen by
userspace. The new attribute file shows '1' for user
selected rng and '0' otherwise.
Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch rewoks the hwrng to always use the
rng source with best entropy quality.
On registation and unregistration the hwrng now
tries to choose the best (= highest quality value)
rng source. The handling of the internal list
of registered rng sources is now always sorted
by quality and the top most rng chosen.
Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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<linux/sched.h> into <linux/sched/signal.h>
Fix up affected files that include this signal functionality via sched.h.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto update from Herbert Xu:
"API:
- Try to catch hash output overrun in testmgr
- Introduce walksize attribute for batched walking
- Make crypto_xor() and crypto_inc() alignment agnostic
Algorithms:
- Add time-invariant AES algorithm
- Add standalone CBCMAC algorithm
Drivers:
- Add NEON acclerated chacha20 on ARM/ARM64
- Expose AES-CTR as synchronous skcipher on ARM64
- Add scalar AES implementation on ARM64
- Improve scalar AES implementation on ARM
- Improve NEON AES implementation on ARM/ARM64
- Merge CRC32 and PMULL instruction based drivers on ARM64
- Add NEON acclerated CBCMAC/CMAC/XCBC AES on ARM64
- Add IPsec AUTHENC implementation in atmel
- Add Support for Octeon-tx CPT Engine
- Add Broadcom SPU driver
- Add MediaTek driver"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (142 commits)
crypto: xts - Add ECB dependency
crypto: cavium - switch to pci_alloc_irq_vectors
crypto: cavium - switch to pci_alloc_irq_vectors
crypto: cavium - remove dead MSI-X related define
crypto: brcm - Avoid double free in ahash_finup()
crypto: cavium - fix Kconfig dependencies
crypto: cavium - cpt_bind_vq_to_grp could return an error code
crypto: doc - fix typo
hwrng: omap - update Kconfig help description
crypto: ccm - drop unnecessary minimum 32-bit alignment
crypto: ccm - honour alignmask of subordinate MAC cipher
crypto: caam - fix state buffer DMA (un)mapping
crypto: caam - abstract ahash request double buffering
crypto: caam - fix error path for ctx_dma mapping failure
crypto: caam - fix DMA API leaks for multiple setkey() calls
crypto: caam - don't dma_map key for hash algorithms
crypto: caam - use dma_map_sg() return code
crypto: caam - replace sg_count() with sg_nents_for_len()
crypto: caam - check sg_count() return value
crypto: caam - fix HW S/G in ablkcipher_giv_edesc_alloc()
..
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This reverts commit 2cc751545854d7bd7eedf4d7e377bb52e176cd07.
With this commit in place I get on a Cavium ThunderX (arm64) system:
$ if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v > rng-bad.txt
1+0 records in
1+0 records out
256 bytes (256 B) copied, 9.1171e-05 s, 2.8 MB/s
$ dd if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v >> rng-bad.txt
1+0 records in
1+0 records out
256 bytes (256 B) copied, 9.6141e-05 s, 2.7 MB/s
$ cat rng-bad.txt
000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000050 00 00 00 00 37 20 46 ae d0 fc 1c 55 25 6e b0 b8
000060 7c 7e d7 d4 00 0f 6f b2 91 1e 30 a8 fa 3e 52 0e
000070 06 2d 53 30 be a1 20 0f aa 56 6e 0e 44 6e f4 35
000080 b7 6a fe d2 52 70 7e 58 56 02 41 ea d1 9c 6a 6a
000090 d1 bd d8 4c da 35 45 ef 89 55 fc 59 d5 cd 57 ba
0000a0 4e 3e 02 1c 12 76 43 37 23 e1 9f 7a 9f 9e 99 24
0000b0 47 b2 de e3 79 85 f6 55 7e ad 76 13 4f a0 b5 41
0000c0 c6 92 42 01 d9 12 de 8f b4 7b 6e ae d7 24 fc 65
0000d0 4d af 0a aa 36 d9 17 8d 0e 8b 7a 3b b6 5f 96 47
0000e0 46 f7 d8 ce 0b e8 3e c6 13 a6 2c b6 d6 cc 17 26
0000f0 e3 c3 17 8e 9e 45 56 1e 41 ef 29 1a a8 65 c8 3a
000100
000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
000050 00 00 00 00 f4 90 65 aa 8b f2 5e 31 01 53 b4 d4
000060 06 c0 23 a2 99 3d 01 e4 b0 c1 b1 55 0f 80 63 cf
000070 33 24 d8 3a 1d 5e cd 2c ba c0 d0 18 6f bc 97 46
000080 1e 19 51 b1 90 15 af 80 5e d1 08 0d eb b0 6c ab
000090 6a b4 fe 62 37 c5 e1 ee 93 c3 58 78 91 2a d5 23
0000a0 63 50 eb 1f 3b 84 35 18 cf b2 a4 b8 46 69 9e cf
0000b0 0c 95 af 03 51 45 a8 42 f1 64 c9 55 fc 69 76 63
0000c0 98 9d 82 fa 76 85 24 da 80 07 29 fe 4e 76 0c 61
0000d0 ff 23 94 4f c8 5c ce 0b 50 e8 31 bc 9d ce f4 ca
0000e0 be ca 28 da e6 fa cc 64 1c ec a8 41 db fe 42 bd
0000f0 a0 e2 4b 32 b4 52 ba 03 70 8e c1 8e d0 50 3a c6
000100
To my untrained mental entropy detector, the first several bytes of
each read from /dev/hwrng seem to not be very random (i.e. all zero).
When I revert the patch (apply this patch), I get back to what we have
in v4.9, which looks like (much more random appearing):
$ dd if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v > rng-good.txt
1+0 records in
1+0 records out
256 bytes (256 B) copied, 0.000252233 s, 1.0 MB/s
$ dd if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v >> rng-good.txt
1+0 records in
1+0 records out
256 bytes (256 B) copied, 0.000113571 s, 2.3 MB/s
$ cat rng-good.txt
000000 75 d1 2d 19 68 1f d2 26 a1 49 22 61 66 e8 09 e5
000010 e0 4e 10 d0 1a 2c 45 5d 59 04 79 8e e2 b7 2c 2e
000020 e8 ad da 34 d5 56 51 3d 58 29 c7 7a 8e ed 22 67
000030 f9 25 b9 fb c6 b7 9c 35 1f 84 21 35 c1 1d 48 34
000040 45 7c f6 f1 57 63 1a 88 38 e8 81 f0 a9 63 ad 0e
000050 be 5d 3e 74 2e 4e cb 36 c2 01 a8 14 e1 38 e1 bb
000060 23 79 09 56 77 19 ff 98 e8 44 f3 27 eb 6e 0a cb
000070 c9 36 e3 2a 96 13 07 a0 90 3f 3b bd 1d 04 1d 67
000080 be 33 14 f8 02 c2 a4 02 ab 8b 5b 74 86 17 f0 5e
000090 a1 d7 aa ef a6 21 7b 93 d1 85 86 eb 4e 8c d0 4c
0000a0 56 ac e4 45 27 44 84 9f 71 db 36 b9 f7 47 d7 b3
0000b0 f2 9c 62 41 a3 46 2b 5b e3 80 63 a4 35 b5 3c f4
0000c0 bc 1e 3a ad e4 59 4a 98 6c e8 8d ff 1b 16 f8 52
0000d0 05 5c 2f 52 2a 0f 45 5b 51 fb 93 97 a4 49 4f 06
0000e0 f3 a0 d1 1e ba 3d ed a7 60 8f bb 84 2c 21 94 2d
0000f0 b3 66 a6 61 1e 58 30 24 85 f8 c8 18 c3 77 00 22
000100
000000 73 ca cc a1 d9 bb 21 8d c3 5c f3 ab 43 6d a7 a4
000010 4a fd c5 f4 9c ba 4a 0f b1 2e 19 15 4e 84 26 e0
000020 67 c9 f2 52 4d 65 1f 81 b7 8b 6d 2b 56 7b 99 75
000030 2e cd d0 db 08 0c 4b df f3 83 c6 83 00 2e 2b b8
000040 0f af 61 1d f2 02 35 74 b5 a4 6f 28 f3 a1 09 12
000050 f2 53 b5 d2 da 45 01 e5 12 d6 46 f8 0b db ed 51
000060 7b f4 0d 54 e0 63 ea 22 e2 1d d0 d6 d0 e7 7e e0
000070 93 91 fb 87 95 43 41 28 de 3d 8b a3 a8 8f c4 9e
000080 30 95 12 7a b2 27 28 ff 37 04 2e 09 7c dd 7c 12
000090 e1 50 60 fb 6d 5f a8 65 14 40 89 e3 4c d2 87 8f
0000a0 34 76 7e 66 7a 8e 6b a3 fc cf 38 52 2e f9 26 f0
0000b0 98 63 15 06 34 99 b2 88 4f aa d8 14 88 71 f1 81
0000c0 be 51 11 2b f4 7e a0 1e 12 b2 44 2e f6 8d 84 ea
0000d0 63 82 2b 66 b3 9a fd 08 73 5a c2 cc ab 5a af b1
0000e0 88 e3 a6 80 4b fc db ed 71 e0 ae c0 0a a4 8c 35
0000f0 eb 89 f9 8a 4b 52 59 6f 09 7c 01 3f 56 e7 c7 bf
000100
Signed-off-by: David Daney <david.daney@cavium.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch remove the unused PFX macro.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch move the define for hwrng's miscdev minor number to
include/linux/miscdevice.h.
It's better that all minor number are in the same place.
Rename it to HWRNG_MINOR (from RNG_MISCDEV_MINOR) in he process since
no other miscdev define have MISCDEV in their name.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch fix the checkpatch warning about asm/uaccess.h.
In the same time, we sort the headers in alphabetical order.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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checkpatch have lot of complaint about header.
Furthermore, the header have some offtopic/useless information.
This patch rewrite a proper header.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch fix the checkpatch warning "Comparison to NULL could be written "!ptr"
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This patch fix the checkpatch warning "Please don't use multiple blank lines"
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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