https://git.reactos.org/?p=reactos.git;a=commitdiff;h=85f42a25d5bcda5ce1720e247b5907d372f0c042
commit 85f42a25d5bcda5ce1720e247b5907d372f0c042
Author: Timo Kreuzer <timo.kreu...@reactos.org>
AuthorDate: Fri Dec 13 12:59:28 2024 +0200
Commit: Timo Kreuzer <timo.kreu...@reactos.org>
CommitDate: Wed Jan 22 14:04:18 2025 +0200
[NTOS:KE/x64] Improve freeze code
- Set ACTIVE flag on freeze owner like on Windows
- Add a nice state graph
- Change license to MIT
---
ntoskrnl/ke/amd64/freeze.c | 41 ++++++++++++++++++++++++++++++++++-------
1 file changed, 34 insertions(+), 7 deletions(-)
diff --git a/ntoskrnl/ke/amd64/freeze.c b/ntoskrnl/ke/amd64/freeze.c
index 5cf53f3f27f..5e655d32939 100644
--- a/ntoskrnl/ke/amd64/freeze.c
+++ b/ntoskrnl/ke/amd64/freeze.c
@@ -1,8 +1,30 @@
/*
* PROJECT: ReactOS Kernel
- * LICENSE: GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
+ * LICENSE: MIT (https://spdx.org/licenses/MIT)
* PURPOSE: Processor freeze support for x64
- * COPYRIGHT: Copyright 2023 Timo Kreuzer <timo.kreu...@reactos.org>
+ * COPYRIGHT: Copyright 2023-2024 Timo Kreuzer <timo.kreu...@reactos.org>
+ */
+
+/*
+
+ IpiFrozen state graph (based on Windows behavior):
+
+ +-----------------+ Freeze request +-----------------+
+ | RUNNING |------------------------>| TARGET_FREEZE |
+ +-----------------+<--------- +-----------------+
+ |^ | Resume |
+ Freeze || Thaw +-----------+ Thaw request | Freeze IPI
+ v| | THAW |<-----------\ v
+ +-----------------+ +-----------+ +-----------------+
+ | OWNER + ACTIVE | ^ | FROZEN |
+ +-----------------+ | +-----------------+
+ ^ | ^
+ | Kd proc switch | | Kd proc switch
+ v | v
+ +-----------------+ | +-----------------+
+ | OWNER |---------+ | FROZEN + ACTIVE |
+ +-----------------+ Thaw request +-----------------+
+
*/
/* INCLUDES
*******************************************************************/
@@ -98,8 +120,8 @@ KxFreezeExecution(
}
}
- /* We are the owner now */
- CurrentPrcb->IpiFrozen = IPI_FROZEN_STATE_OWNER;
+ /* We are the owner now and active */
+ CurrentPrcb->IpiFrozen = IPI_FROZEN_STATE_OWNER | IPI_FROZEN_FLAG_ACTIVE;
/* Loop all processors */
for (ULONG i = 0; i < KeNumberProcessors; i++)
@@ -107,7 +129,7 @@ KxFreezeExecution(
PKPRCB TargetPrcb = KiProcessorBlock[i];
if (TargetPrcb != CurrentPrcb)
{
- /* Nobody else is allowed to change IpiFrozen, except the freeze
owner */
+ /* Only the active processor is allowed to change IpiFrozen */
ASSERT(TargetPrcb->IpiFrozen == IPI_FROZEN_STATE_RUNNING);
/* Request target to freeze */
@@ -142,6 +164,7 @@ KxThawExecution(
VOID)
{
PKPRCB CurrentPrcb = KeGetCurrentPrcb();
+ ASSERT(CurrentPrcb->IpiFrozen & IPI_FROZEN_FLAG_ACTIVE);
/* Loop all processors */
for (ULONG i = 0; i < KeNumberProcessors; i++)
@@ -190,6 +213,10 @@ KxSwitchKdProcessor(
/* Make sure that the processor index is valid */
ASSERT(ProcessorIndex < KeNumberProcessors);
+ /* We are no longer active */
+ ASSERT(CurrentPrcb->IpiFrozen & IPI_FROZEN_FLAG_ACTIVE);
+ CurrentPrcb->IpiFrozen &= ~IPI_FROZEN_FLAG_ACTIVE;
+
/* Inform the target processor that it's his turn now */
TargetPrcb = KiProcessorBlock[ProcessorIndex];
TargetPrcb->IpiFrozen |= IPI_FROZEN_FLAG_ACTIVE;
@@ -212,12 +239,12 @@ KxSwitchKdProcessor(
{
/* Another CPU has completed, we can leave the debugger now */
KdpDprintf("[%u] KxSwitchKdProcessor: ContinueSuccess\n",
KeGetCurrentProcessorNumber());
- CurrentPrcb->IpiFrozen = IPI_FROZEN_STATE_OWNER;
+ CurrentPrcb->IpiFrozen = IPI_FROZEN_STATE_OWNER |
IPI_FROZEN_FLAG_ACTIVE;
return ContinueSuccess;
}
/* We have been reselected, return to Kd to continue in the debugger */
- CurrentPrcb->IpiFrozen = IPI_FROZEN_STATE_OWNER;
+ ASSERT(CurrentPrcb->IpiFrozen == (IPI_FROZEN_STATE_OWNER |
IPI_FROZEN_FLAG_ACTIVE));
return ContinueProcessorReselected;
}
