add docs

microsoft · Oct 1, 2024 · f623c40 · f623c40
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Showing 5 changed files with 17 additions and 14 deletions.
diff --git a/Common/MU_TIANO b/Common/MU_TIANO
diff --git a/Features/CONFIG b/Features/CONFIG
diff --git a/Features/DEBUGGER b/Features/DEBUGGER
diff --git a/Platforms/Docs/Common/debugging.md b/Platforms/Docs/Common/debugging.md
@@ -8,22 +8,25 @@ This document described different ways to debug on the QEMU platforms.
 Both Q35 and SBSA are setup to debug debugged using the MU debugger package. for
 more details on using this debugger, see the [FeatureDebuggerPkg Readme](https://github.com/microsoft/mu_feature_debugger/blob/main/DebuggerFeaturePkg/Readme.md).
 
-By default the debugger is disabled, to enable you must both enable the debugger
-build flag to enable the source debug device state flag and specify a serial port
-TCP port.
-
+By default the debugger is enabled to break in on exceptions, but not to break in
+on an initial breakpoint. To enable the initial breakpoint in DXE, you must pass:
 ```
-stuart_build -c Platforms\QemuQ35Pkg\PlatformBuild.py BLD_*_DEBUGGER_ENABLED=TRUE SERIAL_PORT=5555 --flashrom
+stuart_build -c Platforms\QemuQ35Pkg\PlatformBuild.py BLD_*_DXE_DBG_BRK=TRUE --FlashRom
 ```
 
 On Q35 this allows for debugging over a different port then the usual debug output
 because Q35 has a seperate serial port available to it. On SBSA the serial port
-will be shared with the logging output.
+will be shared with the logging output. As a result, on Q35, if `SERIAL_PORT=<PORT>`
+is not passed on the cmdline, a default serial port at 50001 will be created. On SBSA,
+no default port is set because it will prevent output from occuring on stdout, which
+makes even telling if an exception occurred difficult.
+
+Currently this will only enable the DXE debugger. The MM debugger will be added to Q35
+once it support supervised Standalone MM.
 
-Currently this will only enable the DXE debugger. The MM debugger must be manually
-enabled using the PcdForceEnableDebugger if the DebugAgent has been configured.
-By default, the DXE debugger will stall for 30 seconds on the initial breakpoint
-before attempting to continue execution.
+When an exception occurs, the debugger will break in and wait for a debugger client to
+connect. This makes Q35 and SBSA very debuggable, because they will break in on
+exceptions always, meaning a reboot is not required.
 
 ## Debugging using QEMU GDB Server
 

diff --git a/Silicon/Arm/MU_TIANO b/Silicon/Arm/MU_TIANO