[FREELDR] Add KD support

Some limitations:
- only debug output is supported
- NOT tested with WinDBG

boot/freeldr/freeldr/CMakeLists.txt

@@ -33,7 +33,8 @@ list(APPEND FREELDR_BOOTLIB_SOURCE
     lib/cache/blocklist.c
     lib/cache/cache.c
     lib/comm/rs232.c
-    ## add KD support
+    ../../../drivers/base/kdnet/kdnet.c
+    lib/kdstub.c
     lib/fs/btrfs.c
     lib/fs/ext2.c
     lib/fs/fat.c

boot/freeldr/freeldr/include/comm.h

@@ -23,6 +23,6 @@
 
 BOOLEAN Rs232PortInitialize(ULONG ComPort, ULONG BaudRate);
 BOOLEAN Rs232PortGetByte(PUCHAR ByteReceived);
-// BOOLEAN Rs232PortPollByte(PUCHAR ByteReceived);
+BOOLEAN Rs232PortPollByte(PUCHAR ByteReceived);
 VOID Rs232PortPutByte(UCHAR ByteToSend);
 BOOLEAN Rs232PortInUse(PUCHAR Base);

boot/freeldr/freeldr/include/freeldr.h

@@ -65,6 +65,7 @@
 #include <disk.h>
 #include <fs.h>
 #include <inifile.h>
+#include <kd.h>
 #include <keycodes.h>
 #include <linux.h>
 #include <custom.h>

boot/freeldr/freeldr/include/kd.h

@@ -0,0 +1,15 @@
+/*
+ * PROJECT:     FreeLoader
+ * LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
+ * PURPOSE:     Kernel debugger header file for the FreeLoader
+ * COPYRIGHT:   Copyright 2001-2003 Brian Palmer <brianp@sginet.com>
+ *              Copyright 2022 Hervé Poussineau <hpoussin@reactos.org>
+ */
+
+#pragma once
+
+#include <windbgkd.h>
+#include <kddll.h>
+#include <kdnetextensibility.h>
+
+VOID DebugPrintChar(UCHAR Character);

boot/freeldr/freeldr/lib/comm/rs232.c

@@ -121,13 +121,11 @@ BOOLEAN Rs232PortGetByte(PUCHAR ByteReceived)
     return (CpGetByte(&Rs232ComPortInfo, ByteReceived, TRUE, FALSE) == CP_GET_SUCCESS);
 }
 
-/*
 BOOLEAN Rs232PortPollByte(PUCHAR ByteReceived)
 {
     if (Rs232ComPort == 0) return FALSE;
     return (CpGetByte(&Rs232ComPortInfo, ByteReceived, FALSE, FALSE) == CP_GET_SUCCESS);
 }
-*/
 
 VOID Rs232PortPutByte(UCHAR ByteToSend)
 {

boot/freeldr/freeldr/lib/debug.c

@@ -194,6 +194,13 @@ Done:
         if (!Rs232PortInitialize(ComPort, BaudRate))
             DebugPort &= ~RS232;
     }
+
+    {
+        LOADER_PARAMETER_BLOCK LoaderBlock = {0};
+        LoaderBlock.LoadOptions = (PCHAR)CmdLineGetDebugString();
+        KdDebuggerInitialize0(&LoaderBlock);
+        KdDebuggerInitialize1(&LoaderBlock);
+    }
 }
 
 VOID DebugPrintChar(UCHAR Character)
@@ -218,12 +225,32 @@ VOID DebugPrintChar(UCHAR Character)
     }
 }
 
+VOID
+DbgPrintString(
+    _In_ PCHAR Buffer,
+    _In_ ULONG Length)
+{
+    DBGKD_DEBUG_IO DebugIo = {0};
+    STRING MessageHeader;
+    STRING MessageData;
+
+    /* Prepare packet to send to debugger */
+    DebugIo.ApiNumber = DbgKdPrintStringApi;
+    DebugIo.u.PrintString.LengthOfString = Length;
+    MessageHeader.Buffer = (PCHAR)&DebugIo;
+    MessageHeader.Length = sizeof(DebugIo);
+    MessageData.Buffer = Buffer;
+    MessageData.Length = Length;
+
+    /* Send packet to debugger */
+    KdSendPacket(PACKET_TYPE_KD_DEBUG_IO, &MessageHeader, &MessageData, NULL);
+}
+
 ULONG
 DbgPrint(const char *Format, ...)
 {
     va_list ap;
     int Length;
-    char* ptr;
     CHAR Buffer[512];
 
     va_start(ap, Format);
@@ -240,9 +267,7 @@ DbgPrint(const char *Format, ...)
         Length = sizeof(Buffer);
     }
 
-    ptr = Buffer;
-    while (Length--)
-        DebugPrintChar(*ptr++);
+    DbgPrintString(Buffer, Length);
 
     return 0;
 }
@@ -252,7 +277,7 @@ DbgPrint2(ULONG Mask, ULONG Level, const char *File, ULONG Line, char *Format, .
 {
     va_list ap;
     char Buffer[2096];
-    char *ptr = Buffer;
+    int Length;
 
     /* Mask out unwanted debug messages */
     if (!(DbgChannels[Mask] & Level) && !(Level & DBG_DEFAULT_LEVELS))
@@ -285,13 +310,10 @@ DbgPrint2(ULONG Mask, ULONG Level, const char *File, ULONG Line, char *Format, .
     }
 
     va_start(ap, Format);
-    vsprintf(Buffer, Format, ap);
+    Length = vsprintf(Buffer, Format, ap);
     va_end(ap);
 
-    while (*ptr)
-    {
-        DebugPrintChar(*ptr++);
-    }
+    DbgPrintString(Buffer, Length);
 }
 
 VOID

boot/freeldr/freeldr/lib/kdstub.c

@@ -0,0 +1,197 @@
+/*
+ * PROJECT:     FreeLoader
+ * LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
+ * PURPOSE:     I/O functions for the freeldr debugger
+ * COPYRIGHT:   Copyright 2022 Hervé Poussineau <hpoussin@reactos.org>
+ */
+
+#include <freeldr.h>
+
+static UCHAR KdTxMessageBuffer[4096];
+static UCHAR KdRxMessageBuffer[4096];
+
+static NTSTATUS
+NTAPI
+KdpGetRxPacketWinKD(
+    _In_ PVOID Adapter,
+    _Out_ PULONG Handle,
+    _Out_ PVOID *Packet,
+    _Out_ PULONG Length)
+{
+    ULONG DataLength = 0;
+    ULONG Retries;
+
+    do
+    {
+        for (Retries = 100; Retries > 0; Retries--)
+        {
+            if (Rs232PortPollByte(&KdRxMessageBuffer[DataLength]))
+            {
+                DataLength++;
+                break;
+            }
+        }
+    } while (Retries > 0);
+
+    if (DataLength == 0)
+        return STATUS_IO_TIMEOUT;
+
+    *Handle = 1;
+    *Packet = KdRxMessageBuffer;
+    *Length = DataLength;
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS
+NTAPI
+KdpGetRxPacketDirectOutput(
+    _In_ PVOID Adapter,
+    _Out_ PULONG Handle,
+    _Out_ PVOID *Packet,
+    _Out_ PULONG Length)
+{
+    *(PULONG)(KdRxMessageBuffer + 0) = PACKET_LEADER;
+    *(PUSHORT)(KdRxMessageBuffer + 4) = PACKET_TYPE_KD_ACKNOWLEDGE;
+    *(PUSHORT)(KdRxMessageBuffer + 6) = 0; // ByteCount
+    *(PULONG)(KdRxMessageBuffer + 8) = INITIAL_PACKET_ID; // PacketId
+    *(PULONG)(KdRxMessageBuffer + 12) = 0; // CheckSum
+    *(KdRxMessageBuffer + 16) = PACKET_TRAILING_BYTE;
+
+    *Handle = 1;
+    *Packet = KdRxMessageBuffer;
+    *Length = 17;
+    return STATUS_SUCCESS;
+}
+
+static VOID
+NTAPI
+KdpReleaseRxPacket(
+    _In_ PVOID Adapter,
+    _In_ ULONG Handle)
+{
+}
+
+static NTSTATUS
+NTAPI
+KdpGetTxPacket(
+    _In_ PVOID Adapter,
+    _Out_ PULONG Handle)
+{
+    *Handle = 0;
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS
+NTAPI
+KdpSendTxPacketWinKD(
+    _In_ PVOID Adapter,
+    _In_ ULONG Handle,
+    _In_ ULONG Length)
+{
+    PUCHAR ByteBuffer = KdTxMessageBuffer;
+
+    while (Length-- > 0)
+    {
+        Rs232PortPutByte(*ByteBuffer++);
+    }
+    return STATUS_SUCCESS;
+}
+
+static NTSTATUS
+NTAPI
+KdpSendTxPacketDirectOutput(
+    _In_ PVOID Adapter,
+    _In_ ULONG Handle,
+    _In_ ULONG Length)
+{
+    PKD_PACKET Packet = (PKD_PACKET)KdTxMessageBuffer;
+    PDBGKD_DEBUG_IO DebugIo;
+    PCHAR Buffer;
+    ULONG BufferLength, i;
+
+    if (Packet->PacketType != PACKET_TYPE_KD_DEBUG_IO)
+        return STATUS_SUCCESS;
+
+    DebugIo = (PDBGKD_DEBUG_IO)(Packet + 1);
+    if (DebugIo->ApiNumber != DbgKdPrintStringApi)
+        return STATUS_SUCCESS;
+
+    BufferLength = Packet->ByteCount - sizeof(DBGKD_DEBUG_IO);
+    Buffer = (PCHAR)(DebugIo + 1);
+    for (i = 0; i < BufferLength; i++)
+        DebugPrintChar(Buffer[i]);
+
+    return STATUS_SUCCESS;
+}
+
+static PVOID
+NTAPI
+KdpGetPacketAddress(
+    _In_ PVOID Adapter,
+    _In_ ULONG Handle)
+{
+    if (Handle == 0)
+        return KdTxMessageBuffer;
+    else if (Handle == 1)
+        return KdRxMessageBuffer;
+    else
+        return NULL;
+}
+
+static ULONG
+NTAPI
+KdpGetPacketLength(
+    _In_ PVOID Adapter,
+    _In_ ULONG Handle)
+{
+    if (Handle == 0)
+        return sizeof(KdTxMessageBuffer);
+    else if (Handle == 1)
+        return sizeof(KdRxMessageBuffer);
+    else
+        return 0;
+}
+
+static KDNET_EXTENSIBILITY_EXPORTS KdWinKDExports = {
+    KDNET_EXT_EXPORTS,
+    NULL,
+    NULL,
+    NULL,
+    KdpGetRxPacketWinKD,
+    KdpReleaseRxPacket,
+    KdpGetTxPacket,
+    KdpSendTxPacketWinKD,
+    KdpGetPacketAddress,
+    KdpGetPacketLength,
+};
+
+static KDNET_EXTENSIBILITY_EXPORTS KdDirectOutputExports = {
+    KDNET_EXT_EXPORTS,
+    NULL,
+    NULL,
+    NULL,
+    KdpGetRxPacketDirectOutput,
+    KdpReleaseRxPacket,
+    KdpGetTxPacket,
+    KdpSendTxPacketDirectOutput,
+    KdpGetPacketAddress,
+    KdpGetPacketLength,
+};
+
+NTSTATUS
+NTAPI
+KdInitializeLibrary(
+    _In_ PKDNET_EXTENSIBILITY_IMPORTS ImportTable,
+    _In_opt_ PCHAR LoaderOptions,
+    _Inout_ PDEBUG_DEVICE_DESCRIPTOR Device)
+{
+#ifdef _WINKD_
+    if (1)
+#else
+    if (0)
+#endif
+        ImportTable->Exports = &KdWinKDExports;
+    else
+        ImportTable->Exports = &KdDirectOutputExports;
+    return STATUS_SUCCESS;
+}