[ros-arm-bringup] 32308: Fix a couple of MMU bugs (incrementing the base address before writing the PTE and using the wrong start base address). Virtual memory now works! FreeLDR now boots into the kernel, at 0x80801000, in KiSystemStartup!

Author: ros-arm-bringup
Date: Tue Feb 12 02:47:43 2008
New Revision: 32308

URL: http://svn.reactos.org/svn/reactos?rev=32308&view=rev
Log:
Fix a couple of MMU bugs (incrementing the base address before writing the PTE and using the wrong start base address).
Virtual memory now works!
FreeLDR now boots into the kernel, at 0x80801000, in KiSystemStartup!

Modified:
    trunk/reactos/boot/freeldr/freeldr/arch/arm/stubs.c

Modified: trunk/reactos/boot/freeldr/freeldr/arch/arm/stubs.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/a...
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/arm/stubs.c (original)
+++ trunk/reactos/boot/freeldr/freeldr/arch/arm/stubs.c Tue Feb 12 02:47:43 2008
@@ -191,6 +191,7 @@
 LOADER_PARAMETER_BLOCK ArmLoaderBlock;
 LOADER_PARAMETER_EXTENSION ArmExtension;
 extern ARM_TRANSLATION_TABLE ArmTranslationTable;
+extern ROS_KERNEL_ENTRY_POINT KernelEntryPoint;

/* FUNCTIONS ******************************************************************/

@@ -232,7 +233,7 @@
 FORCEINLINE
 ArmControlRegisterSet(IN ARM_CONTROL_REGISTER ControlRegister)
 {
-    __asm__ __volatile__ ("mcr p15, 0, %0, c1, c0, 0; b ." : : "r"(ControlRegister.AsUlong) : "cc");    
+    __asm__ __volatile__ ("mcr p15, 0, %0, c1, c0, 0" : : "r"(ControlRegister.AsUlong) : "cc");    
 }

VOID
@@ -271,7 +272,6 @@
     //
     TtbRegister.AsUlong = (ULONG)TranslationTable;
     ASSERT(TtbRegister.Reserved == 0);
-    TuiPrintf("CP15 C2: %x\n", TtbRegister);
     ArmMmuTtbSet(TtbRegister);

//
@@ -279,7 +279,6 @@
     //
     DomainRegister.AsUlong = 0;
     DomainRegister.Domain0 = ClientDomain;
-    TuiPrintf("CP15 C3: %x\n", DomainRegister);
     ArmMmuDomainRegisterSet(DomainRegister);

//
@@ -296,29 +295,26 @@
     Pte.L1.Section.Reserved = 1; // ARM926EJ-S manual recommends setting to 1
     Pte.L1.Section.Domain = Domain0;
     Pte.L1.Section.Access = SupervisorAccess;
-    Pte.L1.Section.BaseAddress = KSEG0_BASE >> TTB_SHIFT;
+    Pte.L1.Section.BaseAddress = 0;
     Pte.L1.Section.Ignored = Pte.L1.Section.Ignored1 = 0;
-    TuiPrintf("Template PTE: %x\n", Pte.AsUlong);
-    TuiPrintf("Base: %x %x\n", KSEG0_BASE, Pte.L1.Section.BaseAddress);
-    
-    //
-    // Map KSEG0 (0x80000000 - 0xA0000000)
-    //
-    TuiPrintf("First PTE Index: %x\n", KSEG0_BASE >> TTB_SHIFT);
-    TuiPrintf("Last PTE Index: %x\n", ((KSEG0_BASE + 0x20000000) >> TTB_SHIFT));
+    
+    //
+    // Map KSEG0 (0x80000000 - 0xA0000000) to 0x00000000 - 0x80000000
+    // In this way, the KERNEL_PHYS_ADDR (0x800000) becomes 0x80800000
+    // which is the entrypoint, just like on x86.
+    //
     for (i = (KSEG0_BASE >> TTB_SHIFT); i < ((KSEG0_BASE + 0x20000000) >> TTB_SHIFT); i++)
     {
         //
-        // Update the PTE base address (next MB)
+        // Write PTE and update the base address (next MB) for the next one
         //
+        TranslationTable->Pte[i] = Pte;
         Pte.L1.Section.BaseAddress++;
-        TranslationTable->Pte[i] = Pte;
     }

//
-    // Identity map the first MB of memory
-    //
-    TuiPrintf("Last KSEG0 PTE: %x %x\n", i, Pte.AsUlong);
+    // Identity map the first MB of memory as well
+    //
     Pte.L1.Section.BaseAddress = 0;
     TranslationTable->Pte[0] = Pte;
 }
@@ -329,28 +325,18 @@
     ARM_CONTROL_REGISTER ControlRegister;

//
-    // This is it! Once we enable the MMU we're in a totally different universe.
-    // Cross our fingers: We mapped the bottom 1MB of memory, so FreeLDR and
-    // boot-data is still there. We also mapped the kernel, and made our
-    // allocations | KSEG0_BASE. If any of this isn't true, we're dead.
-    //
-    TuiPrintf("Crossing the Rubicon!\n");
-    
-    //
     // Enable MMU, DCache and ICache
     //
     ControlRegister = ArmControlRegisterGet();
-    TuiPrintf("CP15 C1: %x\n", ControlRegister);
     ControlRegister.MmuEnabled = TRUE;
     ControlRegister.ICacheEnabled = TRUE;
     ControlRegister.DCacheEnabled = TRUE;
-    TuiPrintf("CP15 C1: %x\n", ControlRegister);
     ArmControlRegisterSet(ControlRegister);

//
-    // Are we still alive?
-    //
-    while (TRUE);
+    // Jump to Kernel
+    //
+    (*KernelEntryPoint)(Magic, (PVOID)&ArmLoaderBlock);
 }

VOID