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path: root/drivers/char/hw_random
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2023-07-28hwrng: cctrng - let devres enable the clockMartin Kaiser
Call devm_clk_get_optional_enabled in the cctrng driver. We don't have to disable and unprepare the clock any more in error paths or in the remove function. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-28hwrng: cctrng - don't open code init and exit functionsMartin Kaiser
Do not open code the init and exit functions of the cctrng driver. If we move the BUILD_BUG_ON checks into the probe function, we can use module_platform_driver and make the code shorter. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: arm-smccc-trng - don't set drvdataMartin Kaiser
Don't set drvdata, there's nobody who reads it. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ba431 - use dev_err_probe after failed registrationMartin Kaiser
Use dev_err_probe to print the error message after a failed hwrng registration. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ba431 - don't init of_device_id's dataMartin Kaiser
We have no device-specific data for silex-insight,ba431-rng. There's no need to set .data = NULL, this is the default. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ba431 - do not set drvdataMartin Kaiser
Do not set drvdata in the ba431 driver. Nobody is using it. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ingenic - switch to device managed registrationMartin Kaiser
Call devm_hwrng_register for device managed registration of the ingenic-trng driver. ingenic_trng_remove can then be deleted. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ingenic - don't disable the rng in ingenic_trng_removeMartin Kaiser
There's no need to disable the rng in ingenic_trng_remove. The driver's init function sets the CFG_GEN_EN bit to enable the rng. The cleanup function clears CFG_GEN_EN to revert this. The remove function calls hwrng_unregister. If the ingenic-trng is not the current rng at this point, CFG_GEN_EN has already been cleared. If the ingenic-trng is the current rng, drop_current_rng will call the cleanup function. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ingenic - use dev_err_probe in error pathsMartin Kaiser
Use dev_err_probe in error paths to make the code a bit shorter. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ingenic - use devm_clk_get_enabledMartin Kaiser
Use devm_clk_get_enabled in the ingenic-trng driver. We don't have to disable and unprepare the clock any more in error paths or in the remove function. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ingenic - remove dead assignmentsMartin Kaiser
Don't assign a value to ret if we're about to return from the probe function and ret's value is not used. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ingenic - remove two unused definesMartin Kaiser
Remove two defines which are not used in the ingenic-trng driver's code. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-22hwrng: ingenic - enable compile testingMartin Kaiser
Enable compile testing for the ingenic-trng driver. Remove the dependency on HW_RANDOM. The ingenic-trng config section is under "if HW_RANDOM". Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: timeriomem - Use devm_platform_get_and_ioremap_resource()Yangtao Li
Convert platform_get_resource(), devm_ioremap_resource() to a single call to devm_platform_get_and_ioremap_resource(), as this is exactly what this function does. Signed-off-by: Yangtao Li <frank.li@vivo.com> Reviewed-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: pic32 - enable TRNG only while it's usedMartin Kaiser
The probe function enables the TRNG hardware before registering the driver. If registration fails, probe returns an error, but the TRNG remains enabled. Define init and cleanup functions, enable and disable the hardware there. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: pic32 - remove unused definesMartin Kaiser
Remove some unused defines and fix the indentation. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: pic32 - use devm_clk_get_enabledMartin Kaiser
Use devm_clk_get_enabled in the pic32 driver. Ensure that the clock is enabled as long as the driver is registered with the hwrng core. Fixes: 7ea39973d1e5 ("hwrng: pic32 - Use device-managed registration API") Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: pic32 - enable compile-testingMartin Kaiser
Enable compile testing for the pic32 driver. Remove the dependency on HW_RANDOM. The pic32 config section is under "if HW_RANDOM". Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: exynos - switch to DEFINE_SIMPLE_DEV_PM_OPSMartin Kaiser
SIMPLE_DEV_PM_OPS is deprecated, replace it with DEFINE_SIMPLE_DEV_PM_OPS and use pm_sleep_ptr for setting the driver's pm routines. We can now remove the __maybe_unused qualifier in the suspend and resume functions. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: imx-rngc - use dev_err_probeMartin Kaiser
Simplify the code by calling dev_err_probe instead of dev_err and return. While at it, use the same device for all error messages. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Reviewed-by: Rouven Czerwinski <r.czerwinskis@pengutronix.de> Reviewed-by: Rouven Czerwinski <r.czerwinski@pengutronix.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: nomadik - use dev_err_probeMartin Kaiser
Use dev_err_probe to print a message and return an error. This makes the code a tiny bit shorter. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-07-20hwrng: nomadik - keep clock enabled while hwrng is registeredMartin Kaiser
The nomadik driver uses devres to register itself with the hwrng core, the driver will be unregistered from hwrng when its device goes out of scope. This happens after the driver's remove function is called. However, nomadik's clock is disabled in the remove function. There's a short timeframe where nomadik is still registered with the hwrng core although its clock is disabled. I suppose the clock must be active to access the hardware and serve requests from the hwrng core. Switch to devm_clk_get_enabled and let devres disable the clock and unregister the hwrng. This avoids the race condition. Fixes: 3e75241be808 ("hwrng: drivers - Use device-managed registration API") Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-06-23hwrng: imx-rngc - switch to DEFINE_SIMPLE_DEV_PM_OPSMartin Kaiser
SIMPLE_DEV_PM_OPS is deprecated, replace it with DEFINE_SIMPLE_DEV_PM_OPS and use pm_sleep_ptr for setting the driver's pm routines. We can now remove the __maybe_unused qualifier in the suspend and resume functions. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-06-23hwrng: st - keep clock enabled while hwrng is registeredMartin Kaiser
The st-rng driver uses devres to register itself with the hwrng core, the driver will be unregistered from hwrng when its device goes out of scope. This happens after the driver's remove function is called. However, st-rng's clock is disabled in the remove function. There's a short timeframe where st-rng is still registered with the hwrng core although its clock is disabled. I suppose the clock must be active to access the hardware and serve requests from the hwrng core. Switch to devm_clk_get_enabled and let devres disable the clock and unregister the hwrng. This avoids the race condition. Fixes: 3e75241be808 ("hwrng: drivers - Use device-managed registration API") Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-06-23hwrng: st - support compile-testingMartin Kaiser
Allow compile-testing the st-rng driver if we're not running on an ST chipset. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-06-23hwrng: imx-rngc - fix the timeout for init and self checkMartin Kaiser
Fix the timeout that is used for the initialisation and for the self test. wait_for_completion_timeout expects a timeout in jiffies, but RNGC_TIMEOUT is in milliseconds. Call msecs_to_jiffies to do the conversion. Cc: stable@vger.kernel.org Fixes: 1d5449445bd0 ("hwrng: mx-rngc - add a driver for Freescale RNGC") Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-06-02hwrng: cn10k - Add extended trng register supportBharat Bhushan
The way random data is read from hardware has changed from Octeon CN10KA-B0 and later SoCs onwards. A new set of registers have been added to read random data and to verify whether the read data is valid or not. This patch extends and uses RNM_PF_TRNG_DAT and RNM_PF_TRNG_STS CSRs to read random number and status for the applicable silicon variants. Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-24hwrng: imx-rngc - don't init of_device_id's dataMartin Kaiser
We have no device-specific data for fsl,imx25-rngb. There's no need to set .data = NULL, this is the default. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-24hwrng: imx-rngc - mark the probe function as __initMartin Kaiser
Mark the imx_rngc_probe function as __init. There's no need to support hotplugging in the imx-rngc driver. We use module_platform_driver_probe, the probe function will only be called at startup. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-24hwrng: imx-rngc - use BIT(x) for register bit definesMartin Kaiser
Rewrite the defines for register bits to use BIT(x) instead of writing out the 32-bit number. This makes it easier to compare the code with the register descriptions in the reference manual. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-24hwrng: imx-rngc - use bitfield macros to read rng typeMartin Kaiser
Use the mechanism from bitfield.h to read the rng type field in the version_id register. This makes the code a tiny bit simpler. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-24hwrng: imx-rngc - simpler check for available random bytesMartin Kaiser
The "level" field in the status register contains the number of random bytes that are available in the FIFO. Use GENMASK to extract this field. We only want to check if level is 0 or if we can read another byte. There's no need for the shift or the level variable. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-12hwrng: virtio - Fix race on data_avail and actual dataHerbert Xu
The virtio rng device kicks off a new entropy request whenever the data available reaches zero. When a new request occurs at the end of a read operation, that is, when the result of that request is only needed by the next reader, then there is a race between the writing of the new data and the next reader. This is because there is no synchronisation whatsoever between the writer and the reader. Fix this by writing data_avail with smp_store_release and reading it with smp_load_acquire when we first enter read. The subsequent reads are safe because they're either protected by the first load acquire, or by the completion mechanism. Also remove the redundant zeroing of data_idx in random_recv_done (data_idx must already be zero at this point) and data_avail in request_entropy (ditto). Reported-by: syzbot+726dc8c62c3536431ceb@syzkaller.appspotmail.com Fixes: f7f510ec1957 ("virtio: An entropy device, as suggested by hpa.") Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-12hwrng: histb - Move driver to drivers/char/hw_random/histb-rng.cDavid Yang
Move to drivers/char/hw_random since histb-(t)rng does not provide cryptography pseudo rng. histb-rng is pretty like hisi-rng, but after investigation, we confirm there is no RNG_PHY_SEED register on histb-rng so a separate driver is needed. Still we rename relevant function names to match those in hisi-rng. Link: https://lore.kernel.org/r/20230401164448.1393336-1-mmyangfl@gmail.com Signed-off-by: David Yang <mmyangfl@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-05-12hwrng: Kconfig - Add HAS_IOMEM dependencies for exynos/meson/mtk/npcmHerbert Xu
Add missing dependencies on HAS_IOMEM as otherwise they will trigger failed builds with COMPILE_TEST enabled. Also add dependencies on OF where appropriate. Change the default so that these drivers are not enabled just because COMPILE_TEST is turned on. Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/oe-kbuild-all/202304191106.swKbBeDh-lkp@intel.com/ Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Łukasz Stelmach <l.stelmach@samsung.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-03-24hwrng: xgene - remove unnecessary (void*) conversionsYu Zhe
Pointer variables of void * type do not require type cast. Signed-off-by: Yu Zhe <yuzhe@nfschina.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-03-14hwrng: meson - remove not needed call to platform_set_drvdataHeiner Kallweit
drvdata isn't used, therefore remove this call. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-03-14hwrng: meson - use devm_clk_get_optional_enabledHeiner Kallweit
Use devm_clk_get_optional_enabled() to simplify the code. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-03-14hwrng: meson - remove unused member of struct meson_rng_dataHeiner Kallweit
Member pdev isn't used, remove it. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-03-14hwrng: xgene - Improve error reporting for problems during .remove()Uwe Kleine-König
Returning an error value in a platform driver's remove callback results in a generic error message being emitted by the driver core, but otherwise it doesn't make a difference. The device goes away anyhow. As the driver already emits a better error message than the core, suppress the generic error message by returning zero unconditionally. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-03-10hwrng: xgene - Simplify using devm_clk_get_optional_enabled()Uwe Kleine-König
Instead of ignoring errors returned by devm_clk_get() and manually enabling the clk for the whole lifetime of the bound device, use devm_clk_get_optional_enabled(). This is simpler and also more correct as it doesn't ignore errors. This is also more correct because now the call to clk_disable_unprepare() can be dropped from xgene_rng_remove() which happened while the hwrn device was still registered. With the devm callback disabling the clk happens correctly only after devm_hwrng_register() is undone. As a result struct xgene_rng_dev::clk is only used in xgene_rng_probe, and so the struct member can be replaced by a local variable. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-03-10hwrng: xgene - Simplify using dev_err_probe()Uwe Kleine-König
dev_err_probe simplifies the idiom: if (ret != -EPROBE_DEFER) dev_err(...) return ret; , emits the error code in a human readable way and even yields a useful entry in /sys/kernel/debug/devices_deferred in the EPROBE_DEFER case. So simplify and at the same time improve the driver by using dev_err_probe(). Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-02-03hwrng: starfive - Enable compile testingHerbert Xu
Enable compile testing for jh7110. Also remove the dependency on HW_RANDOM. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Jia Jie Ho <jiajie.ho@starfivetech.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-01-27hwrng: starfive - Add TRNG driver for StarFive SoCJia Jie Ho
This adds driver support for the hardware random number generator in Starfive SoCs and adds StarFive TRNG entry to MAINTAINERS. Co-developed-by: Jenny Zhang <jenny.zhang@starfivetech.com> Signed-off-by: Jenny Zhang <jenny.zhang@starfivetech.com> Signed-off-by: Jia Jie Ho <jiajie.ho@starfivetech.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-12-20random: do not include <asm/archrandom.h> from random.hJason A. Donenfeld
The <asm/archrandom.h> header is a random.c private detail, not something to be called by other code. As such, don't make it automatically available by way of random.h. Cc: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-12-14Merge tag 'v6.2-p1' of ↵Linus Torvalds
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 ...
2022-12-09hwrng: geode - Fix PCI device refcount leakXiongfeng Wang
for_each_pci_dev() is implemented by pci_get_device(). The comment of pci_get_device() says that it will increase the reference count for the returned pci_dev and also decrease the reference count for the input pci_dev @from if it is not NULL. If we break for_each_pci_dev() loop with pdev not NULL, we need to call pci_dev_put() to decrease the reference count. We add a new struct 'amd_geode_priv' to record pointer of the pci_dev and membase, and then add missing pci_dev_put() for the normal and error path. Fixes: ef5d862734b8 ("[PATCH] Add Geode HW RNG driver") Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-12-09hwrng: amd - Fix PCI device refcount leakXiongfeng Wang
for_each_pci_dev() is implemented by pci_get_device(). The comment of pci_get_device() says that it will increase the reference count for the returned pci_dev and also decrease the reference count for the input pci_dev @from if it is not NULL. If we break for_each_pci_dev() loop with pdev not NULL, we need to call pci_dev_put() to decrease the reference count. Add the missing pci_dev_put() for the normal and error path. Fixes: 96d63c0297cc ("[PATCH] Add AMD HW RNG driver") Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-11-18hwrng: stm32 - rename readl return valueTomas Marek
Use a more meaningful name for the readl return value variable. Link: https://lore.kernel.org/all/Y1J3QwynPFIlfrIv@loth.rohan.me.apana.org.au/ Signed-off-by: Tomas Marek <tomas.marek@elrest.cz> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-11-18hwrng: core - treat default_quality as a maximum and default to 1024Jason A. Donenfeld
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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