Mario Limonciello f1324bbc40 tpm: disable hwrng for fTPM on some AMD designs ... AMD has issued an advisory indicating that having fTPM enabled in BIOS can cause "stuttering" in the OS. This issue has been fixed in newer versions of the fTPM firmware, but it's up to system designers to decide whether to distribute it. This issue has existed for a while, but is more prevalent starting with kernel 6.1 because commit b006c439d5 ("hwrng: core - start hwrng kthread also for untrusted sources") started to use the fTPM for hwrng by default. However, all uses of /dev/hwrng result in unacceptable stuttering. So, simply disable registration of the defective hwrng when detecting these faulty fTPM versions. As this is caused by faulty firmware, it is plausible that such a problem could also be reproduced by other TPM interactions, but this hasn't been shown by any user's testing or reports. It is hypothesized to be triggered more frequently by the use of the RNG because userspace software will fetch random numbers regularly. Intentionally continue to register other TPM functionality so that users that rely upon PCR measurements or any storage of data will still have access to it. If it's found later that another TPM functionality is exacerbating this problem a module parameter it can be turned off entirely and a module parameter can be introduced to allow users who rely upon fTPM functionality to turn it on even though this problem is present. Link: https://www.amd.com/en/support/kb/faq/pa-410 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216989 Link: https://lore.kernel.org/all/20230209153120.261904-1-Jason@zx2c4.com/ Fixes: b006c439d5 ("hwrng: core - start hwrng kthread also for untrusted sources") Cc: stable@vger.kernel.org Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Tested-by: reach622@mailcuk.com Tested-by: Bell <1138267643@qq.com> Co-developed-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>		2023-03-12 23:28:10 +02:00
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agp	char/agp: consolidate {alloc,free}_gatt_pages()	2023-02-13 22:13:12 +01:00
hw_random	hwrng: starfive - Enable compile testing	2023-02-03 12:55:59 +08:00
ipmi	ipmi: ipmb: Fix the MODULE_PARM_DESC associated to 'retry_time_ms'	2023-02-10 07:38:18 -06:00
mwave	…
pcmcia	Char/Misc and other driver subsystem changes for 6.3-rc1	2023-02-24 12:47:33 -08:00
tpm	tpm: disable hwrng for fTPM on some AMD designs	2023-03-12 23:28:10 +02:00
xilinx_hwicap	…
xillybus	…
Kconfig	…
Makefile	…
adi.c	…
apm-emulation.c	…
applicom.c	applicom: Fix PCI device refcount leak in applicom_init()	2023-01-20 13:05:39 +01:00
applicom.h	…
bsr.c	…
ds1620.c	…
dsp56k.c	…
dtlk.c	…
hangcheck-timer.c	…
hpet.c	…
lp.c	…
mem.c	mm/nommu: factor out check for NOMMU shared mappings into is_nommu_shared_mapping()	2023-01-18 17:12:56 -08:00
misc.c	…
mspec.c	mm: replace vma->vm_flags direct modifications with modifier calls	2023-02-09 16:51:39 -08:00
nsc_gpio.c	…
nvram.c	…
nwbutton.c	…
nwbutton.h	…
nwflash.c	…
pc8736x_gpio.c	…
powernv-op-panel.c	…
ppdev.c	…
ps3flash.c	…
random.c	cpumask: fix incorrect cpumask scanning result checks	2023-03-06 12:15:13 -08:00
scx200_gpio.c	…
sonypi.c	…
tlclk.c	…
toshiba.c	…
ttyprintk.c	…
uv_mmtimer.c	…
virtio_console.c	virtio_console: Use strscpy() to instead of strncpy()	2023-01-20 13:07:54 +01:00