has been restored, it will restore the TPM PCRs and then
transfer control back to the kernel's S3 resume vector.
In order to preserve system integrity across S3, the kernel
- provides tboot with a set of memory ranges (kernel
- code/data/bss, S3 resume code, and AP trampoline) that tboot
- will calculate a MAC (message authentication code) over and then
- seal with the TPM. On resume and once the measured environment
- has been re-established, tboot will re-calculate the MAC and
- verify it against the sealed value. Tboot's policy determines
- what happens if the verification fails.
+ provides tboot with a set of memory ranges (RAM and RESERVED_KERN
+ in the e820 table, but not any memory that BIOS might alter over
+ the S3 transition) that tboot will calculate a MAC (message
+ authentication code) over and then seal with the TPM. On resume
+ and once the measured environment has been re-established, tboot
+ will re-calculate the MAC and verify it against the sealed value.
+ Tboot's policy determines what happens if the verification fails.
+ Note that the c/s 194 of tboot which has the new MAC code supports
+ this.
That's pretty much it for TXT support.