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path: root/drivers/firmware/turris-mox-rwtm.c
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2022-11-18hwrng: core - treat default_quality as a maximum and default to 1024Jason A. Donenfeld1-1/+0
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>
2021-06-23Merge tag 'mvebu-drivers-5.14-1' of ↵Olof Johansson1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gclement/mvebu into arm/drivers mvebu drivers for 5.14 (part 1) Make the turris mox rwtm firmware more generic for Armada 3700 SoCs * tag 'mvebu-drivers-5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/gclement/mvebu: firmware: turris-mox-rwtm: add marvell,armada-3700-rwtm-firmware compatible string Link: https://lore.kernel.org/r/87bl802a2d.fsf@BL-laptop Signed-off-by: Olof Johansson <olof@lixom.net>
2021-06-17firmware: turris-mox-rwtm: add marvell,armada-3700-rwtm-firmware compatible ↵Pali Rohár1-0/+1
string Add more generic compatible string 'marvell,armada-3700-rwtm-firmware' for this driver, since it can also be used on other Armada 3720 devices. Current compatible string 'cznic,turris-mox-rwtm' is kept for backward compatibility. Signed-off-by: Pali Rohár <pali@kernel.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2021-06-17firmware: turris-mox-rwtm: show message about HWRNG registrationPali Rohár1-0/+2
Currently it is hard to determinate if on Armada 3720 device is HWRNG by running kernel accessible or not. So print information message into dmesg when HWRNG is available and registration was successful. Fixes: 389711b37493 ("firmware: Add Turris Mox rWTM firmware driver") Signed-off-by: Pali Rohár <pali@kernel.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2021-06-17firmware: turris-mox-rwtm: fail probing when firmware does not support hwrngPali Rohár1-0/+28
When Marvell's rWTM firmware, which does not support the GET_RANDOM command, is used, kernel prints an error message hwrng: no data available every 10 seconds. Fail probing of this driver if the rWTM firmware does not support the GET_RANDOM command. Fixes: 389711b37493 ("firmware: Add Turris Mox rWTM firmware driver") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2021-06-17firmware: turris-mox-rwtm: report failures betterMarek Behún1-6/+12
Report a notice level message if a command is not supported by the rWTM firmware. This should not be an error, merely a notice, because the firmware can be used on boards that do not have manufacturing information burned. Fixes: 389711b37493 ("firmware: Add Turris Mox rWTM firmware driver") Signed-off-by: Marek Behún <kabel@kernel.org> Reviewed-by: Pali Rohár <pali@kernel.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2021-06-17firmware: turris-mox-rwtm: fix reply status decoding functionMarek Behún1-2/+5
The status decoding function mox_get_status() currently contains an incorrect check: if the error status is not MBOX_STS_SUCCESS, it always returns -EIO, so the comparison to MBOX_STS_FAIL is never executed and we don't get the actual error code sent by the firmware. Fix this. Signed-off-by: Marek Behún <kabel@kernel.org> Reviewed-by: Pali Rohár <pali@kernel.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Fixes: 389711b37493 ("firmware: Add Turris Mox rWTM firmware driver") Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2021-04-09treewide: change my e-mail address, fix my nameMarek Behún1-2/+2
Change my e-mail address to kabel@kernel.org, and fix my name in non-code parts (add diacritical mark). Link: https://lkml.kernel.org/r/20210325171123.28093-2-kabel@kernel.org Signed-off-by: Marek Behún <kabel@kernel.org> Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jassi Brar <jassisinghbrar@gmail.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-18firmware: turris-mox-rwtm: support ECDSA signatures via debugfsMarek Behún1-0/+166
The firmware on Turris MOX secure processor offers signing messages with ECDSA private key stored in protected OTP memory. The optimal solution would be to register an akcipher provider via kernel's crypto API, but crypto API does not yet support accessing akcipher API from userspace (and probably won't for some time, see https://www.spinics.net/lists/linux-crypto/msg38388.html). At first I tried to put this via standard sysfs API, but the way I designed it is not compatible with sysfs's standard "one file per attribute". This patch therefore adds support for accessing this signature generation mechanism via debugfs. Since CZ.NIC's Turris MOX is the only user of this module, the potential future change to akcipher API should not cause problems, since we can just change our userspace software then. Signed-off-by: Marek Behún <marek.behun@nic.cz> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2020-01-08firmware: turris-mox-rwtm: small white space cleanupDan Carpenter1-1/+1
This patch deletes a stray tab. Cc: Gregory CLEMENT <gregory.clement@bootlin.com> Cc: Colin King <colin.king@canonical.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Marek Behún <marek.behun@nic.cz> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
2019-09-04firmware: Add Turris Mox rWTM firmware driverMarek Behún1-0/+384
This adds a driver to communicate with the firmware running on the secure processor of the Turris Mox router, enabling the kernel to retrieve true random numbers from the Entropy Bit Generator and to read some information burned into eFuses when device was manufactured: and to sign messages with the ECDSA private key burned into each Turris Mox device when manufacturing. This also adds support to read other information burned into eFuses: - serial number - board version - MAC addresses - RAM size - ECDSA public key (this is not read directly from eFuses, rather it is computed by the firmware as pair to the burned private key) The source code of the firmware is open source and can be found at https://gitlab.labs.nic.cz/turris/mox-boot-builder/tree/master/wtmi The firmware is also able to, on demand, sign messages with the burned ECDSA private key, but since Linux's akcipher API is not yet stable (and therefore not exposed to userspace via netlink), this functionality is not supported yet. Link: https://lore.kernel.org/r/20190822014318.19478-3-marek.behun@nic.cz Signed-off-by: Marek Behún <marek.behun@nic.cz> Signed-off-by: Arnd Bergmann <arnd@arndb.de>