[edk2] Apparent timer bug in SourceLevelDebugPkg

[Brian J. Johnson]

SourceLevelDebugPkg maintainers,

I noticed what looks like a regression in the SecPeiDebugAgentLib.
InitializeDebugAgent() calls SaveAndSetDebugTimerInterrupt() before a
normal return, but it is not called when execution continues via
InitializeDebugAgentPhase2(), as in the DEBUG_AGENT_INIT_PREMEM_SEC
case. The result is that debug timer interrupts are not enabled in PEI,
so it's impossible to stop execution via the debugger.

A fix is to add a call to SaveAndSetDebugTimerInterrupt() in
InitializeDebugAgentPhase2(), like the one near the end of
InitializeDebugAgent():

diff --git
a/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
b/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
index fcc7a4b..ea75742 100644
---
a/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
+++
b/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
@@ -684,6 +684,10 @@ InitializeDebugAgentPhase2 (
TriggerSoftInterrupt (MEMORY_READY_SIGNATURE);
}
//
+ // Enable Debug Timer interrupt
+ //
+ SaveAndSetDebugTimerInterrupt (TRUE);
+ //
// Enable CPU interrupts so debug timer interrupts can be delivered
//
EnableInterrupts ();

I haven't tried this fix with the stock SourceLevelDebugPkg, but it
works well in a customized version we use internally.

Thanks,

[Fan, Jeff]

Johnson,

Thanks your fix. I verified it in SourceLevelDebugPkg, it works well.

Could you re-send the patch after refined the commit log format to add TianoCore Contribution Agreement and Signed-off-by section?

Thanks!
Jeff
-----Original Message-----
From: Brian J. Johnson [mailto:***@sgi.com]
Sent: Thursday, July 02, 2015 2:28 AM
To: edk2-***@lists.sourceforge.net; Fan, Jeff
Subject: [edk2] Apparent timer bug in SourceLevelDebugPkg

SourceLevelDebugPkg maintainers,

I noticed what looks like a regression in the SecPeiDebugAgentLib.
InitializeDebugAgent() calls SaveAndSetDebugTimerInterrupt() before a normal return, but it is not called when execution continues via InitializeDebugAgentPhase2(), as in the DEBUG_AGENT_INIT_PREMEM_SEC case. The result is that debug timer interrupts are not enabled in PEI, so it's impossible to stop execution via the debugger.

A fix is to add a call to SaveAndSetDebugTimerInterrupt() in InitializeDebugAgentPhase2(), like the one near the end of
InitializeDebugAgent():

diff --git
a/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
b/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
index fcc7a4b..ea75742 100644
---
a/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
+++
b/SourceLevelDebugPkg/Library/DebugAgent/SecPeiDebugAgent/SecPeiDebugAgentLib.c
@@ -684,6 +684,10 @@ InitializeDebugAgentPhase2 (
TriggerSoftInterrupt (MEMORY_READY_SIGNATURE);
}
//
+ // Enable Debug Timer interrupt
+ //
+ SaveAndSetDebugTimerInterrupt (TRUE);
+ //
// Enable CPU interrupts so debug timer interrupts can be delivered
//
EnableInterrupts ();

I haven't tried this fix with the stock SourceLevelDebugPkg, but it works well in a customized version we use internally.

Thanks,
--

Brian J. Johnson

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