ptos/amd64: Add task state segment

Signed-off-by: Chloe M <chloe@mensia.org>
2026-07-13 23:27:01 -04:00
parent 4165241b6f
commit bb55a52b69
4 changed files with 258 additions and 0 deletions
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Task state segment
+ * Author:      Chloe M.
+ */
+
+#ifndef _MACHINE_TSS_H_
+#define _MACHINE_TSS_H_ 1
+
+#include <ptdef.h>
+
+/*
+ * Represents used interrupt stack table indices
+ *
+ * @IST_RESERVED: This is not used
+ * @IST_NMI:      Stack for NMIs
+ * @IST_SCHED:    Stack for scheduler
+ */
+typedef enum {
+    IST_RESERVED,
+    IST_NMI,
+    IST_SCHED
+} IST_INDEX;
+
+/*
+ * Represents a platform task state segment
+ *
+ * Refer to section 8.7 of the Intel SDM
+ */
+typedef struct PACKED {
+    ULONG Reserved;
+    ULONG Rsp0Low;
+    ULONG Rsp0High;
+    ULONG Rsp1Low;
+    ULONG Rsp1High;
+    ULONG Rsp2Low;
+    ULONG Rsp2High;
+    ULONG Reserved1;
+    ULONG Reserved2;
+    ULONG Ist1Low;
+    ULONG Ist1High;
+    ULONG Ist2Low;
+    ULONG Ist2High;
+    ULONG Ist3Low;
+    ULONG Ist3High;
+    ULONG Ist4Low;
+    ULONG Ist4High;
+    ULONG Ist5Low;
+    ULONG Ist5High;
+    ULONG Ist6Low;
+    ULONG Ist6High;
+    ULONG Ist7Low;
+    ULONG Ist7High;
+    ULONG Reserved3;
+    ULONG Reserved4;
+    USHORT Reserved5;
+    USHORT IoBitmap;
+} TSS_ENTRY;
+
+/*
+ * Task state segment descriptor within GDT
+ *
+ * Refer to section 8.2.3 of the Intel SDM
+ */
+typedef struct PACKED {
+    USHORT SegmentLimit;
+    USHORT BaseLow16;
+    UCHAR BaseMid8;
+    UCHAR Type : 4;
+    UCHAR Zero : 1;
+    UCHAR Dpl  : 2;
+    UCHAR Present : 1;
+    UCHAR SegLimitHigh : 4;
+    UCHAR Avl : 1;
+    UCHAR Unused : 2;
+    UCHAR Gran : 1;
+    UCHAR BaseHighMid8;
+    ULONG BaseHigh32;
+    ULONG Reserved;
+} TSS_DESCRIPTOR;
+
+/*
+ * Allocate an interrupt stack table entry
+ *
+ * @IstIndex:  Interrupt stack table index
+ * @StackSize: Size of stack to allocate
+ */
+VOID MdTssAllocIst(UCHAR IstIndex, USIZE StackSize);
+
+/*
+ * Initialize the task state segment
+ *
+ * @Descriptor:   Task state segment desciptor
+ */
+VOID MdTssInit(TSS_DESCRIPTOR *Descriptor);
+
+#endif  /* !_MACHINE_TSS_H_ */