Date: Mon, 19 Jun 2023 19:09:41 +0100 From: Johannes Totz <jo@bruelltuete.com> To: FreeBSD Hackers <freebsd-hackers@FreeBSD.org> Subject: tpm for AMD Ryzen Message-ID: <f328bc12-b889-2871-e509-0c8664d1c9b3@bruelltuete.com>
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Hi everyone, I'm trying to get the (f)TPM that comes with AMD's Zen2 to work. BIOS config screen says it's doing CRB mode. So I start poking in tpm_crb.c https://github.com/freebsd/freebsd-src/blob/main/sys/dev/tpm/tpm_crb.c Out of the box, it does not attach. The TPM2 ACPI table says its start method is 2 (aka ACPI). That's easy to hack around, just mess with the if-condition at https://github.com/freebsd/freebsd-src/blob/main/sys/dev/tpm/tpm_crb.c#L115 With that adjusted, tpmcrb now probes successfully but does not attach. As far as I can tell the register values it tries to read from the ACPI-provided memory window are just bogus. That makes me suspect that the BIOS has misconfigured it. The TPM2 table has a different address than what's reported at runtime. The table says 0xfd210510 is the (physical) address, but acpi says it's 0xbd13f000. Fiddling about with hint.tpmcrb.0.maddr and friends does not yield anything fruitful: anything I try to override with hints is just ignored. Hacking in a bus_set_resource(dev, SYS_RES_MEMORY, ... 0xfd210510 ...); ends up giving me that override but still no dice re actual tpm functionality. Has anyone gotten the tpm to work on (consumer) Ryzen? thanks, Johannes
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