Change in coreboot[master]: cpu/x86/smm,lib/cbmem_console: Enable CBMEMC when using DEBUG_SMI

[Raul Rangel (Code Review)]

Attention is currently required from: Arthur Heymans, Nico Huber, Martin Roth, Tim Wawrzynczak, Julius Werner, Rob Barnes, Karthik Ramasubramanian.
Hello Arthur Heymans, build bot (Jenkins), Nico Huber, Martin Roth, Tim Wawrzynczak, Julius Werner, Angel Pons, Rob Barnes, Karthik Ramasubramanian,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/62355

to look at the new patch set (#3).

Change subject: cpu/x86/smm,lib/cbmem_console: Enable CBMEMC when using DEBUG_SMI
......................................................................

cpu/x86/smm,lib/cbmem_console: Enable CBMEMC when using DEBUG_SMI

This change will allow the SMI handler to write to the cbmem console
buffer. Normally SMIs can only be debugged using some kind of serial
port (UART). By storing the SMI logs into cbmem we can debug SMIs using
`cbmem -1`. Now that these logs are available to the OS we could also
verify there were no errors in the SMI handler.

Since SMM can write to all of DRAM, we can't trust any pointers
provided by cbmem after the OS has booted. For this reason we store the
cbmem console pointer as part of the SMM runtime parameters. The cbmem
console is implemented as a circular buffer so it will never write
outside of this area.

BUG=b:221231786
TEST=Boot non-serial FW with DEBUG_SMI and verified SMI messages are
visible when running `cbmem -1`. Perform a suspend/resume cycle and
verify new SMI events are written to the cbmem console log.

Signed-off-by: Raul E Rangel 
Change-Id: Ia1e310a12ca2f54210ccfaee58807cb808cfff79
---
M src/cpu/x86/smm/smm_module_handler.c
M src/cpu/x86/smm/smm_module_loader.c
M src/include/console/cbmem_console.h
M src/include/cpu/x86/smm.h
M src/lib/Makefile.inc
M src/lib/cbmem_console.c
6 files changed, 38 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/55/62355/3