[reactos] 02/02: [FREELDR] Improvements for GDT descriptors initialization. Triggered by a fix attempt by M.Harmstone in PR #1905.
13 Oct
2019
13 Oct
'19
5:58 p.m.
https://git.reactos.org/?p=reactos.git;a=commitdiff;h=c85ef31f6a6f0d7ba4fc7…
commit c85ef31f6a6f0d7ba4fc7e72ce65895537b59196
Author: Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
AuthorDate: Sun Oct 13 19:33:00 2019 +0200
Commit: Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
CommitDate: Sun Oct 13 19:57:54 2019 +0200
[FREELDR] Improvements for GDT descriptors initialization.
Triggered by a fix attempt by M.Harmstone in PR #1905.
- Introduce #defines and helper functions so as to initialize the
descriptors in a human-readable and tractable way, without magic values.
- Rework some comments.
- Document what the changes are in (Longhorn and) Vista+.
Data has been obtained through using the WinDbg command: dg 0x00 0xFF
(for example), that lists all the selectors from 0x00 to 0xFF included.
See
https://docs.microsoft.com/en-us/windows-hardware/drivers/debugger/dg--disp…
for more details.
---
boot/freeldr/freeldr/ntldr/arch/i386/winldr.c | 510 +++++++++++++++-----------
1 file changed, 302 insertions(+), 208 deletions(-)
diff --git a/boot/freeldr/freeldr/ntldr/arch/i386/winldr.c
b/boot/freeldr/freeldr/ntldr/arch/i386/winldr.c
index c3917709b32..ae1a7979be9 100644
--- a/boot/freeldr/freeldr/ntldr/arch/i386/winldr.c
+++ b/boot/freeldr/freeldr/ntldr/arch/i386/winldr.c
@@ -6,7 +6,7 @@
* PROGRAMMERS: Aleksey Bragin (aleksey(a)reactos.org)
*/
-/* INCLUDES ***************************************************************/
+/* INCLUDES ******************************************************************/
#include <freeldr.h>
#include <ndk/asm.h>
@@ -23,14 +23,148 @@ DBG_DEFAULT_CHANNEL(WINDOWS);
// This is needed only for SetProcessorContext routine
#pragma pack(2)
- typedef struct
- {
- USHORT Limit;
- ULONG Base;
- } GDTIDT;
+typedef struct
+{
+ USHORT Limit;
+ ULONG Base;
+} GDTIDT;
#pragma pack(4)
-/* GLOBALS ***************************************************************/
+/*
+ * Consider adding these definitions into
+ * ntoskrnl/include/internal/i386/intrin_i.h and/or the NDK.
+ */
+
+#define DPL_SYSTEM 0
+#define DPL_USER 3
+
+#define TYPE_TSS16A 0x01 // 16-bit Task State Segment (Available)
+#define TYPE_LDT 0x02 // Local Descriptor Table
+#define TYPE_TSS16B 0x03 // 16-bit Task State Segment (Busy)
+#define TYPE_CALL16 0x04 // 16-bit Call Gate
+#define TYPE_TASK 0x05 // Task Gate (I386_TASK_GATE)
+#define TYPE_INT16 0x06 // 16-bit Interrupt Gate
+#define TYPE_TRAP16 0x07 // 16-bit Trap Gate
+// #define TYPE_RESERVED_1 0x08
+#define TYPE_TSS32A 0x09 // 32-bit Task State Segment (Available) (I386_TSS)
+// #define TYPE_RESERVED_2 0x0A
+#define TYPE_TSS32B 0x0B // 32-bit Task State Segment (Busy) (I386_ACTIVE_TSS)
+#define TYPE_CALL32 0x0C // 32-bit Call Gate (I386_CALL_GATE)
+// #define TYPE_RESERVED_3 0x0D
+#define TYPE_INT32 0x0E // 32-bit Interrupt Gate (I386_INTERRUPT_GATE)
+#define TYPE_TRAP32 0x0F // 32-bit Trap Gate (I386_TRAP_GATE)
+
+#define DESCRIPTOR_ACCESSED 0x1
+#define DESCRIPTOR_READ_WRITE 0x2
+#define DESCRIPTOR_EXECUTE_READ 0x2
+#define DESCRIPTOR_EXPAND_DOWN 0x4
+#define DESCRIPTOR_CONFORMING 0x4
+#define DESCRIPTOR_CODE 0x8
+
+#define TYPE_CODE (0x10 | DESCRIPTOR_CODE | DESCRIPTOR_EXECUTE_READ)
+#define TYPE_DATA (0x10 | DESCRIPTOR_READ_WRITE)
+
+PKGDTENTRY
+FORCEINLINE
+KiGetGdtEntry(
+ IN PVOID pGdt,
+ IN USHORT Selector)
+{
+ return (PKGDTENTRY)((ULONG_PTR)pGdt + (Selector & ~RPL_MASK));
+}
+
+VOID
+FORCEINLINE
+KiSetGdtDescriptorBase(
+ IN OUT PKGDTENTRY Entry,
+ IN ULONG32 Base)
+{
+ Entry->BaseLow = (USHORT)(Base & 0xffff);
+ Entry->HighWord.Bytes.BaseMid = (UCHAR)((Base >> 16) & 0xff);
+ Entry->HighWord.Bytes.BaseHi = (UCHAR)((Base >> 24) & 0xff);
+ // Entry->BaseUpper = (ULONG)(Base >> 32);
+}
+
+VOID
+FORCEINLINE
+KiSetGdtDescriptorLimit(
+ IN OUT PKGDTENTRY Entry,
+ IN ULONG Limit)
+{
+ if (Limit < 0x100000)
+ {
+ Entry->HighWord.Bits.Granularity = 0;
+ }
+ else
+ {
+ Limit >>= 12;
+ Entry->HighWord.Bits.Granularity = 1;
+ }
+ Entry->LimitLow = (USHORT)(Limit & 0xffff);
+ Entry->HighWord.Bits.LimitHi = ((Limit >> 16) & 0x0f);
+}
+
+VOID
+KiSetGdtEntryEx(
+ IN OUT PKGDTENTRY Entry,
+ IN ULONG32 Base,
+ IN ULONG Limit,
+ IN UCHAR Type,
+ IN UCHAR Dpl,
+ IN BOOLEAN Granularity,
+ IN UCHAR SegMode) // 0: 16-bit, 1: 32-bit, 2: 64-bit
+{
+ KiSetGdtDescriptorBase(Entry, Base);
+ KiSetGdtDescriptorLimit(Entry, Limit);
+ Entry->HighWord.Bits.Type = (Type & 0x1f);
+ Entry->HighWord.Bits.Dpl = (Dpl & 0x3);
+ Entry->HighWord.Bits.Pres = (Type != 0); // Present, must be 1 when the GDT entry
is valid.
+ Entry->HighWord.Bits.Sys = 0; // System
+ Entry->HighWord.Bits.Reserved_0 = 0; // LongMode = !!(SegMode & 1);
+ Entry->HighWord.Bits.Default_Big = !!(SegMode & 2);
+ Entry->HighWord.Bits.Granularity |= !!Granularity; // The flag may have been
already set by KiSetGdtDescriptorLimit().
+ // Entry->MustBeZero = 0;
+}
+
+VOID
+FORCEINLINE
+KiSetGdtEntry(
+ IN OUT PKGDTENTRY Entry,
+ IN ULONG32 Base,
+ IN ULONG Limit,
+ IN UCHAR Type,
+ IN UCHAR Dpl,
+ IN UCHAR SegMode) // 0: 16-bit, 1: 32-bit, 2: 64-bit
+{
+ KiSetGdtEntryEx(Entry, Base, Limit, Type, Dpl, FALSE, SegMode);
+}
+
+#if 0
+VOID
+DumpGDTEntry(ULONG_PTR Base, ULONG Selector)
+{
+ PKGDTENTRY pGdt = (PKGDTENTRY)((ULONG_PTR)Base + Selector);
+
+ TRACE("\n"
+ "Selector 0x%04x\n"
+ "===============\n"
+ "LimitLow = 0x%04x\n"
+ "BaseLow = 0x%04x\n"
+ "HighWord.Bytes.BaseMid = 0x%02x\n"
+ "HighWord.Bytes.Flags1 = 0x%02x\n"
+ "HighWord.Bytes.Flags2 = 0x%02x\n"
+ "HighWord.Bytes.BaseHi = 0x%02x\n"
+ "\n",
+ Selector,
+ pGdt->LimitLow, pGdt->BaseLow,
+ pGdt->HighWord.Bytes.BaseMid,
+ pGdt->HighWord.Bytes.Flags1,
+ pGdt->HighWord.Bytes.Flags2,
+ pGdt->HighWord.Bytes.BaseHi);
+}
+#endif
+
+/* GLOBALS *******************************************************************/
PHARDWARE_PTE PDE;
PHARDWARE_PTE HalPageTable;
@@ -44,7 +178,7 @@ ULONG PcrBasePage;
ULONG TssBasePage;
PVOID GdtIdt;
-/* FUNCTIONS **************************************************************/
+/* FUNCTIONS *****************************************************************/
static
BOOLEAN
@@ -160,7 +294,7 @@ MempSetupPaging(IN PFN_NUMBER StartPage,
if (StartPage+NumberOfPages >= 0x80000)
{
//
- // We can't map this as it requires more than 1 PDE
+ // We cannot map this as it requires more than 1 PDE
// and in fact it's not possible at all ;)
//
//Print(L"skipping...\n");
@@ -259,12 +393,12 @@ static
BOOLEAN
WinLdrMapSpecialPages(void)
{
-
- //VideoDisplayString(L"Hello from VGA, going into the kernel\n");
TRACE("HalPageTable: 0x%X\n", HalPageTable);
- // Page Tables have been setup, make special handling for PCR and TSS
- // (which is done in BlSetupFotNt in usual ntldr)
+ /*
+ * The Page Tables have been setup, make special handling
+ * for the boot processor PCR and KI_USER_SHARED_DATA.
+ */
HalPageTable[(KI_USER_SHARED_DATA - 0xFFC00000) >>
MM_PAGE_SHIFT].PageFrameNumber = PcrBasePage+1;
HalPageTable[(KI_USER_SHARED_DATA - 0xFFC00000) >> MM_PAGE_SHIFT].Valid = 1;
HalPageTable[(KI_USER_SHARED_DATA - 0xFFC00000) >> MM_PAGE_SHIFT].Write = 1;
@@ -273,10 +407,10 @@ WinLdrMapSpecialPages(void)
HalPageTable[(KIP0PCRADDRESS - 0xFFC00000) >> MM_PAGE_SHIFT].Valid = 1;
HalPageTable[(KIP0PCRADDRESS - 0xFFC00000) >> MM_PAGE_SHIFT].Write = 1;
- // Map APIC
+ /* Map APIC */
WinLdrpMapApic();
- // Map VGA memory
+ /* Map VGA memory */
//VideoMemoryBase = MmMapIoSpace(0xb8000, 4000, MmNonCached);
//TRACE("VideoMemoryBase: 0x%X\n", VideoMemoryBase);
@@ -319,13 +453,12 @@ void WinLdrSetupMachineDependent(PLOADER_PARAMETER_BLOCK
LoaderBlock)
LoaderBlock->u.I386.CommonDataArea = NULL; // Force No ABIOS support
LoaderBlock->u.I386.MachineType = MACHINE_TYPE_ISA;
- /* Allocate 2 pages for PCR */
+ /* Allocate 2 pages for PCR: one for the boot processor PCR and one for
KI_USER_SHARED_DATA */
Pcr = (ULONG_PTR)MmAllocateMemoryWithType(2 * MM_PAGE_SIZE, LoaderStartupPcrPage);
PcrBasePage = Pcr >> MM_PAGE_SHIFT;
-
if (Pcr == 0)
{
- UiMessageBox("Can't allocate PCR.");
+ UiMessageBox("Could not allocate PCR.");
return;
}
@@ -334,17 +467,20 @@ void WinLdrSetupMachineDependent(PLOADER_PARAMETER_BLOCK
LoaderBlock)
//TssPages = TssSize / MM_PAGE_SIZE;
Tss = (ULONG_PTR)MmAllocateMemoryWithType(TssSize, LoaderMemoryData);
-
TssBasePage = Tss >> MM_PAGE_SHIFT;
+ if (Tss == 0)
+ {
+ UiMessageBox("Could not allocate TSS.");
+ return;
+ }
/* Allocate space for new GDT + IDT */
BlockSize = NUM_GDT*sizeof(KGDTENTRY) + NUM_IDT*sizeof(KIDTENTRY);//FIXME: Use
GDT/IDT limits here?
NumPages = (BlockSize + MM_PAGE_SIZE - 1) >> MM_PAGE_SHIFT;
GdtIdt = (PKGDTENTRY)MmAllocateMemoryWithType(NumPages * MM_PAGE_SIZE,
LoaderMemoryData);
-
if (GdtIdt == NULL)
{
- UiMessageBox("Can't allocate pages for GDT+IDT!");
+ UiMessageBox("Could not allocate pages for GDT+IDT!");
return;
}
@@ -380,37 +516,36 @@ WinLdrSetProcessorContext(void)
Pcr = KIP0PCRADDRESS;
Tss = KSEG0_BASE | (TssBasePage << MM_PAGE_SHIFT);
- TRACE("GDtIdt %p, Pcr %p, Tss 0x%08X\n",
- GdtIdt, Pcr, Tss);
+ TRACE("GdtIdt %p, Pcr %p, Tss 0x%08x\n",
+ GdtIdt, Pcr, Tss);
- // Enable paging
+ /* Enable paging */
//BS->ExitBootServices(ImageHandle,MapKey);
- // Disable Interrupts
+ /* Disable Interrupts */
_disable();
- // Re-initialize EFLAGS
+ /* Re-initialize EFLAGS */
__writeeflags(0);
- // Set the PDBR
+ /* Set the PDBR */
__writecr3((ULONG_PTR)PDE);
- // Enable paging by modifying CR0
+ /* Enable paging by modifying CR0 */
__writecr0(__readcr0() | CR0_PG);
- // Kernel expects the PCR to be zero-filled on startup
- // FIXME: Why zero it here when we can zero it right after allocation?
- RtlZeroMemory((PVOID)Pcr, MM_PAGE_SIZE); //FIXME: Why zero only 1 page when we
allocate 2?
+ /* The Kernel expects the boot processor PCR to be zero-filled on startup */
+ RtlZeroMemory((PVOID)Pcr, MM_PAGE_SIZE);
- // Get old values of GDT and IDT
+ /* Get old values of GDT and IDT */
Ke386GetGlobalDescriptorTable(&GdtDesc);
__sidt(&IdtDesc);
- // Save old IDT
- OldIdt.Base = IdtDesc.Base;
+ /* Save old IDT */
+ OldIdt.Base = IdtDesc.Base;
OldIdt.Limit = IdtDesc.Limit;
- // Prepare new IDT+GDT
+ /* Prepare new IDT+GDT */
GdtDesc.Base = KSEG0_BASE | (ULONG_PTR)GdtIdt;
GdtDesc.Limit = NUM_GDT * sizeof(KGDTENTRY) - 1;
IdtDesc.Base = (ULONG)((PUCHAR)GdtDesc.Base + GdtDesc.Limit + 1);
@@ -423,170 +558,129 @@ WinLdrSetProcessorContext(void)
pGdt = (PKGDTENTRY)GdtDesc.Base;
pIdt = (PKIDTENTRY)IdtDesc.Base;
- //
- // Code selector (0x8)
- // Flat 4Gb
- //
- pGdt[1].LimitLow = 0xFFFF;
- pGdt[1].BaseLow = 0;
- pGdt[1].HighWord.Bytes.BaseMid = 0;
- pGdt[1].HighWord.Bytes.Flags1 = 0x9A;
- pGdt[1].HighWord.Bytes.Flags2 = 0xCF;
- pGdt[1].HighWord.Bytes.BaseHi = 0;
-
- //
- // Data selector (0x10)
- // Flat 4Gb
- //
- pGdt[2].LimitLow = 0xFFFF;
- pGdt[2].BaseLow = 0;
- pGdt[2].HighWord.Bytes.BaseMid = 0;
- pGdt[2].HighWord.Bytes.Flags1 = 0x92;
- pGdt[2].HighWord.Bytes.Flags2 = 0xCF;
- pGdt[2].HighWord.Bytes.BaseHi = 0;
-
- //
- // Selector (0x18)
- // Flat 2Gb
- //
- pGdt[3].LimitLow = 0xFFFF;
- pGdt[3].BaseLow = 0;
- pGdt[3].HighWord.Bytes.BaseMid = 0;
- pGdt[3].HighWord.Bytes.Flags1 = 0xFA;
- pGdt[3].HighWord.Bytes.Flags2 = 0xCF;
- pGdt[3].HighWord.Bytes.BaseHi = 0;
-
- //
- // Selector (0x20)
- // Flat 2Gb
- //
- pGdt[4].LimitLow = 0xFFFF;
- pGdt[4].BaseLow = 0;
- pGdt[4].HighWord.Bytes.BaseMid = 0;
- pGdt[4].HighWord.Bytes.Flags1 = 0xF2;
- pGdt[4].HighWord.Bytes.Flags2 = 0xCF;
- pGdt[4].HighWord.Bytes.BaseHi = 0;
-
- //
- // TSS Selector (0x28)
- //
- pGdt[5].LimitLow = 0x78-1; //FIXME: Check this
- pGdt[5].BaseLow = (USHORT)(Tss & 0xffff);
- pGdt[5].HighWord.Bytes.BaseMid = (UCHAR)((Tss >> 16) & 0xff);
- pGdt[5].HighWord.Bytes.Flags1 = 0x89;
- pGdt[5].HighWord.Bytes.Flags2 = 0x00;
- pGdt[5].HighWord.Bytes.BaseHi = (UCHAR)((Tss >> 24) & 0xff);
-
- //
- // PCR Selector (0x30)
- //
- pGdt[6].LimitLow = 0x01;
- pGdt[6].BaseLow = (USHORT)(Pcr & 0xffff);
- pGdt[6].HighWord.Bytes.BaseMid = (UCHAR)((Pcr >> 16) & 0xff);
- pGdt[6].HighWord.Bytes.Flags1 = 0x92;
- pGdt[6].HighWord.Bytes.Flags2 = 0xC0;
- pGdt[6].HighWord.Bytes.BaseHi = (UCHAR)((Pcr >> 24) & 0xff);
-
- //
- // Selector (0x38)
- //
- pGdt[7].LimitLow = 0xFFFF;
- pGdt[7].BaseLow = 0;
- pGdt[7].HighWord.Bytes.BaseMid = 0;
- pGdt[7].HighWord.Bytes.Flags1 = 0xF3;
- pGdt[7].HighWord.Bytes.Flags2 = 0x40;
- pGdt[7].HighWord.Bytes.BaseHi = 0;
-
- //
- // Some BIOS stuff (0x40)
- //
- pGdt[8].LimitLow = 0xFFFF;
- pGdt[8].BaseLow = 0x400;
- pGdt[8].HighWord.Bytes.BaseMid = 0;
- pGdt[8].HighWord.Bytes.Flags1 = 0xF2;
- pGdt[8].HighWord.Bytes.Flags2 = 0x0;
- pGdt[8].HighWord.Bytes.BaseHi = 0;
-
- //
- // Selector (0x48)
- //
- pGdt[9].LimitLow = 0;
- pGdt[9].BaseLow = 0;
- pGdt[9].HighWord.Bytes.BaseMid = 0;
- pGdt[9].HighWord.Bytes.Flags1 = 0;
- pGdt[9].HighWord.Bytes.Flags2 = 0;
- pGdt[9].HighWord.Bytes.BaseHi = 0;
-
- //
- // Selector (0x50)
- //
- pGdt[10].LimitLow = 0xFFFF; //FIXME: Not correct!
- pGdt[10].BaseLow = 0;
- pGdt[10].HighWord.Bytes.BaseMid = 0x2;
- pGdt[10].HighWord.Bytes.Flags1 = 0x89;
- pGdt[10].HighWord.Bytes.Flags2 = 0;
- pGdt[10].HighWord.Bytes.BaseHi = 0;
-
- //
- // Selector (0x58)
- //
- pGdt[11].LimitLow = 0xFFFF;
- pGdt[11].BaseLow = 0;
- pGdt[11].HighWord.Bytes.BaseMid = 0x2;
- pGdt[11].HighWord.Bytes.Flags1 = 0x9A;
- pGdt[11].HighWord.Bytes.Flags2 = 0;
- pGdt[11].HighWord.Bytes.BaseHi = 0;
-
- //
- // Selector (0x60)
- //
- pGdt[12].LimitLow = 0xFFFF;
- pGdt[12].BaseLow = 0; //FIXME: Maybe not correct, but noone cares
- pGdt[12].HighWord.Bytes.BaseMid = 0x2;
- pGdt[12].HighWord.Bytes.Flags1 = 0x92;
- pGdt[12].HighWord.Bytes.Flags2 = 0;
- pGdt[12].HighWord.Bytes.BaseHi = 0;
-
- //
- // Video buffer Selector (0x68)
- //
- pGdt[13].LimitLow = 0x3FFF;
- pGdt[13].BaseLow = 0x8000;
- pGdt[13].HighWord.Bytes.BaseMid = 0x0B;
- pGdt[13].HighWord.Bytes.Flags1 = 0x92;
- pGdt[13].HighWord.Bytes.Flags2 = 0;
- pGdt[13].HighWord.Bytes.BaseHi = 0;
-
- //
- // Points to GDT (0x70)
- //
- pGdt[14].LimitLow = NUM_GDT*sizeof(KGDTENTRY) - 1;
- pGdt[14].BaseLow = 0x7000;
- pGdt[14].HighWord.Bytes.BaseMid = 0xFF;
- pGdt[14].HighWord.Bytes.Flags1 = 0x92;
- pGdt[14].HighWord.Bytes.Flags2 = 0;
- pGdt[14].HighWord.Bytes.BaseHi = 0xFF;
-
- //
- // Some unused descriptors should go here
- //
-
- // Copy the old IDT
+ /* KGDT_NULL (0x00) Null Selector - Unused */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_NULL), 0x0000, 0, 0, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_NULL);
+
+ /* KGDT_R0_CODE (0x08) Ring 0 Code selector - Flat 4Gb */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_R0_CODE), 0x0000, 0xFFFFFFFF,
+ TYPE_CODE, DPL_SYSTEM, 2);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_R0_CODE);
+
+ /* KGDT_R0_DATA (0x10) Ring 0 Data selector - Flat 4Gb */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_R0_DATA), 0x0000, 0xFFFFFFFF,
+ TYPE_DATA, DPL_SYSTEM, 2);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_R0_DATA);
+
+ /* KGDT_R3_CODE (0x18) Ring 3 Code Selector - Flat 2Gb */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_R3_CODE), 0x0000, 0xFFFFFFFF,
+ TYPE_CODE, DPL_USER, 2);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_R3_CODE);
+
+ /* KGDT_R3_DATA (0x20) Ring 3 Data Selector - Flat 2Gb */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_R3_DATA), 0x0000, 0xFFFFFFFF,
+ TYPE_DATA, DPL_USER, 2);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_R3_DATA);
+
+ /* KGDT_TSS (0x28) TSS Selector (Ring 0) */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_TSS), (ULONG32)Tss,
+ 0x78-1 /* FIXME: Check this; would be sizeof(KTSS)-1 */,
+ TYPE_TSS32A, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_TSS);
+
+ /*
+ * KGDT_R0_PCR (0x30) PCR Selector (Ring 0)
+ *
+ * IMPORTANT COMPATIBILITY NOTE:
+ * Windows <= Server 2003 sets a Base == KIP0PCRADDRESS (0xffdff000 on x86)
+ * with a Limit of 1 page (LimitLow == 1, Granularity == 1, that is interpreted
+ * as a "Limit" == 0x1fff but is incorrect, of course).
+ * On Windows Longhorn/Vista+ however, the Base is not hardcoded to KIP0PCRADDRESS
+ * and the limit is set in bytes (Granularity == 0):
+ * Longhorn/Vista reports LimitLow == 0x0fff == MM_PAGE_SIZE - 1, whereas
+ * Windows 7+ uses larger sizes there (not aligned on a page boundary).
+ */
+#if 1
+ /* Server 2003 way */
+ KiSetGdtEntryEx(KiGetGdtEntry(pGdt, KGDT_R0_PCR), (ULONG32)Pcr, 0x1,
+ TYPE_DATA, DPL_SYSTEM, TRUE, 2);
+#else
+ /* Vista+ way */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_R0_PCR), (ULONG32)Pcr, MM_PAGE_SIZE - 1,
+ TYPE_DATA, DPL_SYSTEM, 2);
+#endif
+ // DumpGDTEntry(GdtDesc.Base, KGDT_R0_PCR);
+
+ /* KGDT_R3_TEB (0x38) Thread Environment Block Selector (Ring 3) */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_R3_TEB), 0x0000, 0x0FFF,
+ TYPE_DATA | DESCRIPTOR_ACCESSED, DPL_USER, 2);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_R3_TEB);
+
+ /* KGDT_VDM_TILE (0x40) VDM BIOS Data Area Selector (Ring 3) */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_VDM_TILE), 0x0400, 0xFFFF,
+ TYPE_DATA, DPL_USER, 0);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_VDM_TILE);
+
+ /* KGDT_LDT (0x48) LDT Selector (Reserved) */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_LDT), 0x0000, 0, 0, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_LDT);
+
+ /* KGDT_DF_TSS (0x50) Double-Fault Task Switch Selector (Ring 0) */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_DF_TSS), 0x20000 /* FIXME: Not correct! */,
+ 0xFFFF /* FIXME: Not correct! */,
+ TYPE_TSS32A, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_DF_TSS);
+
+ /* KGDT_NMI_TSS (0x58) NMI Task Switch Selector (Ring 0) */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, KGDT_NMI_TSS), 0x20000, 0xFFFF,
+ TYPE_CODE, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, KGDT_NMI_TSS);
+
+ /* Selector (0x60) - Unused (Reserved) on Windows Longhorn/Vista+ */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, 0x60), 0x20000 /* FIXME: Maybe not correct, but
noone cares */,
+ 0xFFFF, TYPE_DATA, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, 0x60);
+
+ /* Video Display Buffer Selector (0x68) - Unused (Reserved) on Windows
Longhorn/Vista+ */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, 0x68), 0xB8000, 0x3FFF,
+ TYPE_DATA, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, 0x68);
+
+ /*
+ * GDT Alias Selector (points to GDT) (0x70)
+ *
+ * IMPORTANT COMPATIBILITY NOTE:
+ * The Base is not fixed to 0xFFFF7000 on Windows Longhorn/Vista+.
+ */
+ KiSetGdtEntry(KiGetGdtEntry(pGdt, 0x70), 0xFFFF7000 /* GdtDesc.Base ?? */,
GdtDesc.Limit,
+ TYPE_DATA, DPL_SYSTEM, 0);
+ // DumpGDTEntry(GdtDesc.Base, 0x70);
+
+ /*
+ * Windows <= Server 2003 defines three additional unused but valid
+ * descriptors there, possibly for debugging purposes only.
+ * They are not present on Windows Longhorn/Vista+.
+ */
+ // KiSetGdtEntry(KiGetGdtEntry(pGdt, 0x78), 0x80400000, 0xffff, TYPE_CODE,
DPL_SYSTEM, 0);
+ // KiSetGdtEntry(KiGetGdtEntry(pGdt, 0x80), 0x80400000, 0xffff, TYPE_DATA,
DPL_SYSTEM, 0);
+ // KiSetGdtEntry(KiGetGdtEntry(pGdt, 0x88), 0x0000, 0, TYPE_DATA, DPL_SYSTEM, 0);
+
+ /* Copy the old IDT */
RtlCopyMemory(pIdt, (PVOID)OldIdt.Base, OldIdt.Limit + 1);
- // Mask interrupts
+ /* Mask interrupts */
//asm("cli\n"); // they are already masked before enabling paged mode
- // Load GDT+IDT
+ /* Load GDT+IDT */
Ke386SetGlobalDescriptorTable(&GdtDesc);
__lidt(&IdtDesc);
- // Jump to proper CS and clear prefetch queue
+ /* Jump to proper CS and clear prefetch queue */
#if defined(__GNUC__)
asm("ljmp $0x08, $1f\n"
"1:\n");
#elif defined(_MSC_VER)
- /* We can't express the above in MASM so we use this far return instead */
+ /* We cannot express the above in MASM so we use this far return instead */
__asm
{
push 8
@@ -598,34 +692,34 @@ WinLdrSetProcessorContext(void)
#error
#endif
- // Set SS selector
- Ke386SetSs(0x10); // DataSelector=0x10
+ /* Set SS selector */
+ Ke386SetSs(KGDT_R0_DATA);
- // Set DS and ES selectors
- Ke386SetDs(0x10);
- Ke386SetEs(0x10); // this is vital for rep stosd
+ /* Set DS and ES selectors */
+ Ke386SetDs(KGDT_R0_DATA);
+ Ke386SetEs(KGDT_R0_DATA); // This is vital for rep stosd
- // LDT = not used ever, thus set to 0
+ /* LDT = not used ever, thus set to 0 */
Ke386SetLocalDescriptorTable(Ldt);
- // Load TSR
+ /* Load TSR */
Ke386SetTr(KGDT_TSS);
- // Clear GS
+ /* Clear GS */
Ke386SetGs(0);
- // Set FS to PCR
- Ke386SetFs(0x30);
-
- // Real end of the function, just for information
- /* do not uncomment!
- pop edi;
- pop esi;
- pop ebx;
- mov esp, ebp;
- pop ebp;
- ret
- */
+ /* Set FS to PCR */
+ Ke386SetFs(KGDT_R0_PCR);
+
+ // Real end of the function, just for information
+ /* do not uncomment!
+ pop edi;
+ pop esi;
+ pop ebx;
+ mov esp, ebp;
+ pop ebp;
+ ret
+ */
}
#if DBG
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Hermès Bélusca-Maïto