Initialize boot CPU structures inside kernel on i686 architecture

xtoskrnl/ar/i686/globals.c

@@ -8,3 +8,12 @@
 
 #include "xtos.h"
 
+
+/* Initial GDT */
+KGDTENTRY ArInitialGdt[GDT_ENTRIES] = {0};
+
+/* Initial IDT */
+KIDTENTRY ArInitialIdt[IDT_ENTRIES] = {0};
+
+/* Initial TSS */
+KTSS ArInitialTss;

xtoskrnl/ar/i686/procsup.c

@@ -20,4 +20,186 @@ XTAPI
 VOID
 ArInitializeProcessor(VOID)
 {
+    PKGDTENTRY Gdt;
+    PKTSS Tss;
+    KDESCRIPTOR GdtDescriptor;
+
+    /* Use initial structures */
+    Gdt = ArInitialGdt;
+    Tss = &ArInitialTss;
+
+    /* Initialize GDT and TSS */
+    ArpInitializeGdt(Gdt);
+    ArpInitializeTss(Tss, Gdt);
+
+    /* Set GDT descriptor */
+    GdtDescriptor.Base = Gdt;
+    GdtDescriptor.Limit = (GDT_ENTRIES * sizeof(PKGDTENTRY)) - 1;
+
+    /* Load GDT and TSS */
+    ArLoadGlobalDescriptorTable(&GdtDescriptor.Limit);
+    ArLoadTaskRegister((UINT32)KGDT_SYS_TSS);
+}
+
+/**
+ * Initializes the kernel's Global Descriptor Table (GDT).
+ *
+ * @param Gdt
+ *        Supplies a pointer to the GDT to use.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+ArpInitializeGdt(IN PKGDTENTRY Gdt)
+{
+    /* Initialize GDT entries */
+    ArpInitializeGdtEntry(Gdt, KGDT_NULL, 0x0, 0x0, 0, KGDT_DPL_SYSTEM, 0);
+    ArpInitializeGdtEntry(Gdt, KGDT_R0_CODE, 0x0, 0xFFFFFFFF, KGDT_TYPE_CODE, KGDT_DPL_SYSTEM, 2);
+    ArpInitializeGdtEntry(Gdt, KGDT_R0_DATA, 0x0, 0xFFFFFFFF, KGDT_TYPE_DATA, KGDT_DPL_SYSTEM, 2);
+    ArpInitializeGdtEntry(Gdt, KGDT_R3_CODE, 0x0, 0xFFFFFFFF, KGDT_TYPE_CODE, KGDT_DPL_USER, 2);
+    ArpInitializeGdtEntry(Gdt, KGDT_R3_DATA, 0x0, 0xFFFFFFFF, KGDT_TYPE_DATA, KGDT_DPL_USER, 2);
+    ArpInitializeGdtEntry(Gdt, KGDT_R3_TEB, 0x0, 0xFFF, KGDT_TYPE_DATA | KGDT_DESCRIPTOR_ACCESSED, KGDT_DPL_USER, 2);
+    ArpInitializeGdtEntry(Gdt, KGDT_R0_LDT, 0x0, 0x0, 0, KGDT_DPL_SYSTEM, 0);
+    ArpInitializeGdtEntry(Gdt, KGDT_VDM_TILE, 0x0400, 0xFFFF, KGDT_TYPE_DATA, KGDT_DPL_USER, 0);
+    ArpInitializeGdtEntry(Gdt, KGDT_R0_PCR, 0x0, 0x1, KGDT_TYPE_DATA, KGDT_DPL_SYSTEM, 2);
+    ArpInitializeGdtEntry(Gdt, KGDT_SYS_TSS, 0x0, sizeof(KTSS) - 1, I686_TSS, KGDT_DPL_SYSTEM, 0);
+    ArpInitializeGdtEntry(Gdt, KGDT_DF_TSS, 0x20000, 0xFFFF, I686_TSS, KGDT_DPL_SYSTEM, 0);
+    ArpInitializeGdtEntry(Gdt, KGDT_NMI_TSS, 0x20000, 0xFFFF, KGDT_TYPE_CODE, KGDT_DPL_SYSTEM, 0);
+}
+
+/**
+ * Fills in an AMD64 GDT entry.
+ *
+ * @param Gdt
+ *        Supplies a pointer to the GDT.
+ *
+ * @param Selector
+ *        Specifies a segment selector of the GDT entry.
+ *
+ * @param Base
+ *        Specifies a base address value of the descriptor.
+ *
+ * @param Limit
+ *        Specifies a descriptor limit.
+ *
+ * @param Type
+ *        Specifies a type of the descriptor.
+ *
+ * @param Dpl
+ *        Specifies the descriptor privilege level.
+ *
+ * @param SegmentMode
+ *        Specifies a segment mode of the descriptor.
+ *
+ * @return This routine does not return any value
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+ArpInitializeGdtEntry(IN PKGDTENTRY Gdt,
+                      IN USHORT Selector,
+                      IN ULONGLONG Base,
+                      IN ULONG Limit,
+                      IN UCHAR Type,
+                      IN UCHAR Dpl,
+                      IN UCHAR SegmentMode)
+{
+    PKGDTENTRY GdtEntry;
+    UCHAR Granularity;
+
+    /* Set the granularity flag depending on descriptor limit */
+    if(Limit < 0x100000)
+    {
+        /* Limit is in 1B blocks */
+        Granularity = 0;
+    }
+    else
+    {
+        /* Limit is in 4KB blocks */
+        Granularity = 1;
+        Limit >>= 12;
+    }
+
+    /* Get GDT entry */
+    GdtEntry = (PKGDTENTRY)((ULONG64)Gdt + (Selector & ~RPL_MASK));
+
+    /* Set GDT descriptor base */
+    GdtEntry->BaseLow = Base & 0xFFFF;
+    GdtEntry->Bits.BaseMiddle = (Base >> 16) & 0xFF;
+    GdtEntry->Bits.BaseHigh = (Base >> 24) & 0xFF;
+
+    /* Set descriptor limit */
+    GdtEntry->LimitLow = Limit & 0xFFFF;
+    GdtEntry->Bits.LimitHigh = (Limit >> 16) & 0xF;
+
+    /* Initialize GDT entry */
+    GdtEntry->Bits.DefaultBig = (SegmentMode & 2);
+    GdtEntry->Bits.Dpl = (Dpl & 0x3);
+    GdtEntry->Bits.Granularity = Granularity;
+    GdtEntry->Bits.Reserved0 = 0;
+    GdtEntry->Bits.Present = (Type != 0);
+    GdtEntry->Bits.System = 0;
+    GdtEntry->Bits.Type = (Type & 0x1F);
+}
+
+/**
+ * Initializes the kernel's Task State Segment (TSS).
+ *
+ * @param Tss
+ *        Supplies a pointer to the TSS to use.
+ *
+ * @param Gdt
+ *        Supplies a pointer to the GDT to use.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+ArpInitializeTss(IN PKTSS Tss,
+                 IN PKGDTENTRY Gdt)
+{
+    PKGDTENTRY TssEntry;
+
+    /* Get TSS entry from GDT */
+    TssEntry = (PKGDTENTRY)(&(Gdt[KGDT_SYS_TSS / sizeof(KGDTENTRY)]));
+
+    /* Initialize TSS entry */
+    TssEntry->Bits.Dpl = 0;
+    TssEntry->Bits.Present = 1;
+    TssEntry->Bits.Type = I686_TSS;
+    TssEntry->LimitLow = sizeof(KTSS) - 1;
+    TssEntry->Bits.LimitHigh = 0;
+
+    /* Clear I/O map */
+    RtlFillMemory(Tss->IoMaps[0].IoMap, IOPM_FULL_SIZE, 0xFF);
+
+    /* Fill Interrupt Direction Maps with zeroes */
+    RtlZeroMemory(Tss->IoMaps[0].DirectionMap, IOPM_DIRECTION_MAP_SIZE);
+
+    /* Enable DPMI support */
+    Tss->IoMaps[0].DirectionMap[0] = 4;
+    Tss->IoMaps[0].DirectionMap[3] = 0x18;
+    Tss->IoMaps[0].DirectionMap[4] = 0x18;
+
+    /* Fill default Interrupt Direction Map with zeroes */
+    RtlZeroMemory(Tss->IntDirectionMap, IOPM_DIRECTION_MAP_SIZE);
+
+    /* Enable DPMI support */
+    Tss->IntDirectionMap[0] = 4;
+    Tss->IntDirectionMap[3] = 0x18;
+    Tss->IntDirectionMap[4] = 0x18;
+
+    /* Set I/O map base and disable traps */
+    Tss->IoMapBase = 0x68;
+    Tss->Flags = 0;
+
+    /* Set LDT and SS */
+    Tss->LDT = KGDT_R0_LDT;
+    Tss->Ss0 = KGDT_R0_DATA;
 }