From b4588d5b4c34918f32bfba80abb0b7338588e2be Mon Sep 17 00:00:00 2001
From: Rafal Kupiec <belliash@codingworkshop.eu.org>
Date: Fri, 24 May 2024 16:30:39 +0200
Subject: [PATCH] Make ExectOS only run on processors which support PAE

---
 sdk/xtdk/i686/mmtypes.h      | 11 ++++-------
 xtoskrnl/ke/amd64/krnlinit.c |  2 --
 xtoskrnl/ke/i686/krnlinit.c  |  2 --
 xtoskrnl/mm/i686/init.c      | 29 +++++------------------------
 xtoskrnl/mm/init.c           | 15 ---------------
 5 files changed, 9 insertions(+), 50 deletions(-)

diff --git a/sdk/xtdk/i686/mmtypes.h b/sdk/xtdk/i686/mmtypes.h
index a57b6b3..3f83e8d 100644
--- a/sdk/xtdk/i686/mmtypes.h
+++ b/sdk/xtdk/i686/mmtypes.h
@@ -20,16 +20,13 @@
 
 /* Page directory and page base addresses */
 #define MM_PTE_BASE                                0xC0000000
-#define MM_PDE_BASE                                0xC0300000
-#define MM_PDE_PAE_BASE                            0xC0600000
+#define MM_PDE_BASE                                0xC0600000
 
 /* PTE shift values */
-#define MM_PTE_SHIFT                               2
+#define MM_PTE_SHIFT                               3
 #define MM_PTI_SHIFT                               12
-#define MM_PDI_SHIFT                               22
-#define MM_PTE_PAE_SHIFT                           3
-#define MM_PDI_PAE_SHIFT                           21
-#define MM_PPI_PAE_SHIFT                           30
+#define MM_PDI_SHIFT                               21
+#define MM_PPI_SHIFT                               30
 
 /* Minimum number of physical pages needed by the system */
 #define MM_MINIMUM_PHYSICAL_PAGES                  1100
diff --git a/xtoskrnl/ke/amd64/krnlinit.c b/xtoskrnl/ke/amd64/krnlinit.c
index ec75688..863fcda 100644
--- a/xtoskrnl/ke/amd64/krnlinit.c
+++ b/xtoskrnl/ke/amd64/krnlinit.c
@@ -20,8 +20,6 @@ XTAPI
 VOID
 KepInitializeKernel(VOID)
 {
-    /* Initialize architecture specific hardware extensions */
-    MmInitializeHardware();
 }
 
 /**
diff --git a/xtoskrnl/ke/i686/krnlinit.c b/xtoskrnl/ke/i686/krnlinit.c
index e8a0adf..e762941 100644
--- a/xtoskrnl/ke/i686/krnlinit.c
+++ b/xtoskrnl/ke/i686/krnlinit.c
@@ -20,8 +20,6 @@ XTAPI
 VOID
 KepInitializeKernel(VOID)
 {
-    /* Initialize architecture specific hardware extensions */
-    MmInitializeHardware();
 }
 
 /**
diff --git a/xtoskrnl/mm/i686/init.c b/xtoskrnl/mm/i686/init.c
index 100f6f6..aed604b 100644
--- a/xtoskrnl/mm/i686/init.c
+++ b/xtoskrnl/mm/i686/init.c
@@ -23,27 +23,11 @@ XTAPI
 PMMPTE
 MmpGetPdeAddress(PVOID Address)
 {
-    ULONG Offset, PdeBase, PdiShift, PteShift;
-
-    /* Get PDI and PTE shifts based on memory extension flag */
-    if(MmpMemoryExtension)
-    {
-        /* Get bit shifts for PAE system */
-        PdeBase = MM_PDE_PAE_BASE;
-        PdiShift = MM_PDI_PAE_SHIFT;
-        PteShift = MM_PTE_PAE_SHIFT;
-    }
-    else
-    {
-        /* Get bit shifts for non-PAE system */
-        PdeBase = MM_PDE_BASE;
-        PdiShift = MM_PDI_SHIFT;
-        PteShift = MM_PTE_SHIFT;
-    }
+    ULONG Offset;
 
     /* Calculate offset and return PTE address */
-    Offset = ((((ULONG)(Address)) >> PdiShift) << PteShift);
-    return (PMMPTE)(PdeBase + Offset);
+    Offset = ((((ULONG)(Address)) >> MM_PDI_SHIFT) << MM_PTE_SHIFT);
+    return (PMMPTE)(MM_PDE_BASE + Offset);
 }
 
 /**
@@ -60,13 +44,10 @@ XTAPI
 PMMPTE
 MmpGetPteAddress(PVOID Address)
 {
-    ULONG Offset, PteShift;
-
-    /* Get PTE shift based on memory extension flag */
-    PteShift = MmpMemoryExtension ? MM_PTE_PAE_SHIFT : MM_PTE_SHIFT;
+    ULONG Offset;
 
     /* Calculate offset and return PTE address */
-    Offset = ((((ULONG)(Address)) >> MM_PTI_SHIFT) << PteShift);
+    Offset = ((((ULONG)(Address)) >> MM_PTI_SHIFT) << MM_PTE_SHIFT);
     return (PMMPTE)(MM_PTE_BASE + Offset);
 }
 
diff --git a/xtoskrnl/mm/init.c b/xtoskrnl/mm/init.c
index 8cd87cf..2aa5ae0 100644
--- a/xtoskrnl/mm/init.c
+++ b/xtoskrnl/mm/init.c
@@ -9,21 +9,6 @@
 #include <xtos.h>
 
 
-/**
- * Performs an early pre-initialization of hardware-related structures.
- *
- * @return This routine does not return any value.
- *
- * @since XT 1.0
- */
-XTAPI
-VOID
-MmInitializeHardware(VOID)
-{
-    /* Check for architecture-specific memory extensions enabled by the firmware or boot loader */
-    MmpMemoryExtension = MmpMemoryExtensionEnabled();
-}
-
 /**
  * Performs an early initialization of the XTOS Memory Manager.
  *