OpenPower PEL Extension support framework

The goal of extensions is to extend phosphor-logging's
`xyz.openbmc_project.Logging.Entry` log support to allow other log
formats to be created without incurring extra D-Bus call overhead.

The README.md change in this commit provides additional documentation on
how extensions work.  The summary is that they allow code that resides
in this repository to provide functions that can be called at certain
points (startup, log creation/deletion) such that the code can then
create their own logs based on the contents of an OpenBMC log.  A
specific extension's code is compiled in using a --enable configure
option, so platforms that did not use those log formats would incur no
performance/size penalties.

This commit provides the support for extensions, plus a basic OpenPower
PEL (Platform Event Log) extension as the first extension.  PELs are
event logs used only on some OpenPower systems.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Ifbb31325261c157678c29bbebc7f6d32d282582f

1 files changed, 8 insertions, 0 deletions

diff --git a/log_manager.hpp b/log_manager.hpp
index e6714af..4b09952 100644
--- a/log_manager.hpp
+++ b/log_manager.hpp
@@ -154,6 +154,14 @@ class Manager : public details::ServerObject<details::ManagerIface>
      */
     static std::string readFWVersion();
 
+    /** @brief Call any create() functions provided by any extensions.
+     *  This is called right after an event log is created to allow
+     *  extensions to create their own log based on this one.
+     *
+     *  @param[in] entry - the new event log entry
+     */
+    void doExtensionLogCreate(const Entry& entry);
+
     /** @brief Persistent sdbusplus DBus bus connection. */
     sdbusplus::bus::bus& busLog;