ELOG: Add support for SMM and kernel GSMI driver

The linux kernel contains an SMI driver that was written by
me (Duncan) and upstreamed a couple years ago called GSMI.
This driver will format a parameter buffer and pass pointers
to this parameter buffer to the SMI handler.  It uses this to
generate events for kernel shutdown reasons:  Clean, Panic, Oops,
etc.

This function expects to be passed pointers into the SMM state
save area that correspond to the prameter buffer and the return
code, which are typically EAX and EBX.

The format of the parameter buffer is defined in the kernel
driver so we implement the same interface here in order to be
compatible.

GSMI_CMD_HANDSHAKE: this is an early call that it does to try
and detect what kind of BIOS is running.

GSMI_CMD_SET_EVENT_LOG: this contains a parameter buffer that
has event type and data.  The kernel-specific events are
translated here and raw events are passed through as well which
allows any run-time event to be added for testing.

GSMI_CMD_CLEAR_EVENT_LOG: this command clears the event log.

First the gsmi driver must be enabled in the kernel with
CONFIG_GOOGLE_GSMI and then events can be added via sysfs
and events are automatically generated for various kernel
shutdown reasons.

These can be seen in the event log as the 'Kernel Event' type:

169 | 2012-06-23 15:03:04 | Kernl Event | Clean Shutdown
181 | 2012-06-23 16:26:32 | Kernl Event | Oops
181 | 2012-06-23 16:26:32 | Kernl Event | Panic

Change-Id: Ic0a3916401f0d9811e4aa8b2c560657dccc920c1
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1316
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/include/elog.h b/src/include/elog.h
index 0542f68fe1..7d89f45d17 100644
--- a/src/include/elog.h
+++ b/src/include/elog.h
@@ -115,6 +115,10 @@ extern void elog_add_event_dword(u8 event_type, u32 data);
 extern void elog_add_event_wake(u8 source, u32 instance);
 extern int elog_smbios_write_type15(unsigned long *current, int handle);
 
+#if CONFIG_ELOG_GSMI
+extern u32 gsmi_exec(u8 command, u32 *param);
+#endif
+
 #if CONFIG_ELOG_BOOT_COUNT
 u32 boot_count_read(void);
 u32 boot_count_increment(void);