[reactos] 05/09: [NTOS:KE] Fix usage of KTHREAD::SwapBusy

[Timo Kreuzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=f4d47faeb7407936f1254…

commit f4d47faeb7407936f125490841ea29cc77eb782d
Author:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
AuthorDate: Mon Jun 7 13:57:32 2021 +0200
Commit:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
CommitDate: Sat Jun 19 12:17:18 2021 +0200

    [NTOS:KE] Fix usage of KTHREAD::SwapBusy
---
 ntoskrnl/ke/amd64/ctxswitch.S  | 8 ++++++++
 ntoskrnl/ke/amd64/thrdini.c    | 3 +++
 sdk/include/asm/ksx.template.h | 1 +
 3 files changed, 12 insertions(+)

diff --git a/ntoskrnl/ke/amd64/ctxswitch.S b/ntoskrnl/ke/amd64/ctxswitch.S
index 94c726aa486..17a87e7c023 100644
--- a/ntoskrnl/ke/amd64/ctxswitch.S
+++ b/ntoskrnl/ke/amd64/ctxswitch.S
@@ -149,6 +149,14 @@ PUBLIC KiThreadStartup
     .allocstack (6 * 8)
     .endprolog
 
+    /* Wait for SwapBusy */
+.SwapBusySet:
+    cmp byte ptr [r8 + ThSwapBusy], 0
+    je .SwapBusyClear
+    pause
+    jmp .SwapBusySet
+.SwapBusyClear:
+
     /* Save WaitIrql as KSWITCH_FRAME::ApcBypass */
     mov [rsp + SwApcBypass], cl
 
diff --git a/ntoskrnl/ke/amd64/thrdini.c b/ntoskrnl/ke/amd64/thrdini.c
index 71d4179843a..044ac7c6396 100644
--- a/ntoskrnl/ke/amd64/thrdini.c
+++ b/ntoskrnl/ke/amd64/thrdini.c
@@ -184,6 +184,9 @@ KiSwapContextResume(
                      0);
     }
 
+    /* Old thread os no longer busy */
+    OldThread->SwapBusy = FALSE;
+
     /* Kernel APCs may be pending */
     if (NewThread->ApcState.KernelApcPending)
     {
diff --git a/sdk/include/asm/ksx.template.h b/sdk/include/asm/ksx.template.h
index 232ad290dca..9cf895d3fd2 100644
--- a/sdk/include/asm/ksx.template.h
+++ b/sdk/include/asm/ksx.template.h
@@ -762,6 +762,7 @@ OFFSET(ThSystemCallNumber, KTHREAD, SystemCallNumber),
 OFFSET(ThTrapFrame, KTHREAD, TrapFrame),
 OFFSET(ThApcState, KTHREAD, ApcState),
 OFFSET(ThPriority, KTHREAD, Priority), // obsolete
+OFFSET(ThSwapBusy, KTHREAD, SwapBusy),
 OFFSET(ThContextSwitches, KTHREAD, ContextSwitches),
 OFFSET(ThState, KTHREAD, State),
 OFFSET(ThProcess, KTHREAD, Process), // thProcess in native headers