[ros-diffs] [reactos] 02/03: [NTOS:KE/x64] Implement KiSetTrapContext

[Timo Kreuzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=f1ed97d6cc9b3acd1ca30…

commit f1ed97d6cc9b3acd1ca305641ec15e76d0a954be
Author:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
AuthorDate: Tue May 15 14:06:27 2018 +0200
Commit:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
CommitDate: Wed Jun 2 18:25:36 2021 +0200

    [NTOS:KE/x64] Implement KiSetTrapContext
    
    KiSetTrapContext is an asm wrapper around RtlSetUnwindContext, which first stores an
exception frame to assure that all non-volatile registers were put on the stack, then
calls RtlSetUnwindContext to update their first saving positions on the stack and finally
restore the exception frame to potentially load any updated registers, that haven't
been saved elsewhere on the stack.
---
 ntoskrnl/ke/amd64/context.c        | 26 ++++++++++++++++++++++++++
 ntoskrnl/ke/amd64/trap.S           | 30 +++++++++++++++++++++++++++---
 sdk/include/asm/ksamd64.template.h |  2 ++
 sdk/include/ndk/amd64/asm.h        |  3 +++
 4 files changed, 58 insertions(+), 3 deletions(-)

diff --git a/ntoskrnl/ke/amd64/context.c b/ntoskrnl/ke/amd64/context.c
index 61c286cd69d..1ce8e8dfe91 100644
--- a/ntoskrnl/ke/amd64/context.c
+++ b/ntoskrnl/ke/amd64/context.c
@@ -292,3 +292,29 @@ KeTrapFrameToContext(IN PKTRAP_FRAME TrapFrame,
     if (OldIrql < APC_LEVEL) KeLowerIrql(OldIrql);
 }
 
+VOID
+RtlSetUnwindContext(
+    _In_ PCONTEXT Context,
+    _In_ DWORD64 TargetFrame);
+
+VOID
+KiSetTrapContextInternal(
+    _Out_ PKTRAP_FRAME TrapFrame,
+    _In_ PCONTEXT Context,
+    _In_ KPROCESSOR_MODE RequestorMode)
+{
+    ULONG64 TargetFrame;
+
+    /* Save the volatile register context in the trap frame */
+    KeContextToTrapFrame(Context,
+                         NULL,
+                         TrapFrame,
+                         Context->ContextFlags,
+                         RequestorMode);
+
+    /* The target frame is MAX_SYSCALL_PARAM_SIZE bytes before the trap frame */
+    TargetFrame = (ULONG64)TrapFrame - MAX_SYSCALL_PARAM_SIZE ;
+
+    /* Set the nonvolatiles on the stack */
+    RtlSetUnwindContext(Context, TargetFrame);
+}
diff --git a/ntoskrnl/ke/amd64/trap.S b/ntoskrnl/ke/amd64/trap.S
index 5d6e1ead384..7fb5c05919b 100644
--- a/ntoskrnl/ke/amd64/trap.S
+++ b/ntoskrnl/ke/amd64/trap.S
@@ -730,9 +730,6 @@ FUNC KiInterruptDispatch
     ExitTrap (TF_SAVE_ALL or TF_SEND_EOI)
 ENDFUNC
 
-
-#define MAX_SYSCALL_PARAM_SIZE (16 * 8)
-
 EXTERN KiSystemCallHandler:PROC
 
 /*! \name KiSystemCallEntry64
@@ -1049,6 +1046,33 @@ KiConvertToGuiThreadFailed:
 
 ENDFUNC
 
+
+EXTERN KiSetTrapContextInternal:PROC
+
+/*
+ * VOID
+ * KiSetTrapContext(
+ *     _Out_ PKTRAP_FRAME TrapFrame,
+ *     _In_ PCONTEXT Context,
+ *     _In_ KPROCESSOR_MODE RequestorMode);
+ */
+PUBLIC KiSetTrapContext
+.PROC KiSetTrapContext
+    
+    /* Generate a KEXCEPTION_FRAME on the stack */
+    GENERATE_EXCEPTION_FRAME
+
+    call KiSetTrapContextInternal
+
+    /* Restore the registers from the KEXCEPTION_FRAME */
+    RESTORE_EXCEPTION_STATE
+
+    /* Return */
+    ret
+
+.ENDP
+
+
 /*
  * VOID
  * KiDeliverApc(
diff --git a/sdk/include/asm/ksamd64.template.h b/sdk/include/asm/ksamd64.template.h
index 41f7e7e4e16..1072df28b34 100644
--- a/sdk/include/asm/ksamd64.template.h
+++ b/sdk/include/asm/ksamd64.template.h
@@ -1071,3 +1071,5 @@ OFFSET(KINTERRUPT_DispatchCount, KINTERRUPT, DispatchCount),
 OFFSET(KINTERRUPT_TrapFrame, KINTERRUPT, TrapFrame),
 OFFSET(KINTERRUPT_DispatchCode, KINTERRUPT, DispatchCode),
 
+HEADER("Misc definitions"),
+CONSTANT(MAX_SYSCALL_PARAM_SIZE),
diff --git a/sdk/include/ndk/amd64/asm.h b/sdk/include/ndk/amd64/asm.h
index 49a5534c3b4..69f3ad2fb17 100644
--- a/sdk/include/ndk/amd64/asm.h
+++ b/sdk/include/ndk/amd64/asm.h
@@ -254,6 +254,9 @@ Author:
 #define CR0_CD                                  HEX(40000000)
 #define CR0_PG                                  HEX(80000000)
 
+/* Number of bytes reserved for syscall parameters */
+#define MAX_SYSCALL_PARAM_SIZE (16 * 8)
+
 #ifdef _ASM_
 //
 // CR4