Handle Exceptions and Uncorrectable Errors
We are getting processes crashes in the fleet which we want to avoid.
Handle exceptions gracefully by reinitializing instead of relying on
systemd reinit (crash and restart).
Also, ensure that we are reading the Uncorrectable Error region first.
The logic should be:
```
1. BIOS_switch ^ BMC_switch == 0 → reserved region has nothing to read
a. CONTINUE
2. BIOS_switch ^ BMC_switch == 1 → reserved region contains unread log
a. Read the Uncorrectable Error log
b. If corruption is detected (log is not parsable)
i. Go through corruption handling flow (reinit)
c. Else toggle the BMC Uncorrectable Error log flag
```
Tested: Added unit test
Signed-off-by: Brandon Kim <brandonkim@google.com>
Change-Id: I8212476be11ea7f13f68e42ff440c2bdd2fc8c2a
diff --git a/src/buffer.cpp b/src/buffer.cpp
index 20427cb..0254cac 100644
--- a/src/buffer.cpp
+++ b/src/buffer.cpp
@@ -6,6 +6,7 @@
#include <boost/endian/arithmetic.hpp>
#include <boost/endian/conversion.hpp>
+#include <stdplus/print.hpp>
#include <algorithm>
#include <array>
@@ -222,6 +223,52 @@
return *reinterpret_cast<struct QueueEntryHeader*>(bytesRead.data());
}
+std::vector<uint8_t> BufferImpl::readUeLogFromReservedRegion()
+{
+ // Ensure cachedBufferHeader is up-to-date
+ readBufferHeader();
+
+ uint16_t currentUeRegionSize =
+ boost::endian::little_to_native(cachedBufferHeader.ueRegionSize);
+ if (currentUeRegionSize == 0)
+ {
+ stdplus::print(stderr,
+ "[readUeLogFromReservedRegion] UE Region size is 0\n");
+ return {};
+ }
+
+ uint32_t biosSideFlags =
+ boost::endian::little_to_native(cachedBufferHeader.biosFlags);
+ uint32_t bmcSideFlags =
+ boost::endian::little_to_native(cachedBufferHeader.bmcFlags);
+
+ // (BIOS_switch ^ BMC_switch) & BIT0 == BIT0 -> unread log
+ // This means if the ueSwitch bit differs, there's an unread log.
+ if (!((biosSideFlags ^ bmcSideFlags) &
+ static_cast<uint32_t>(BufferFlags::ueSwitch)))
+ {
+ return {};
+ }
+ // UE log should be present and unread by BMC, read from end of header
+ // (0x30) to the size of the UE region specified in the header.
+ size_t ueRegionOffset = sizeof(struct CircularBufferHeader);
+ std::vector<uint8_t> ueLogData =
+ dataInterface->read(ueRegionOffset, currentUeRegionSize);
+
+ if (ueLogData.size() == currentUeRegionSize)
+ {
+ return ueLogData;
+ }
+ stdplus::print(stderr,
+ "[readUeLogFromReservedRegion] Failed to read "
+ "full UE log. Expected {}, got {}\n",
+ currentUeRegionSize, ueLogData.size());
+ // Throwing an exception allows main loop to handle re-init.
+ throw std::runtime_error(
+ std::format("Failed to read full UE log. Expected {}, got {}",
+ currentUeRegionSize, ueLogData.size()));
+}
+
EntryPair BufferImpl::readEntry()
{
struct QueueEntryHeader entryHeader = readEntryHeader();