[ros-diffs] [tkreuzer] 52226: [FREELDR] Start implementing a realmode callback mechanism
tkreuzer at svn.reactos.org
tkreuzer at svn.reactos.org
Tue Jun 14 12:17:29 UTC 2011
Author: tkreuzer
Date: Tue Jun 14 12:17:28 2011
New Revision: 52226
URL: http://svn.reactos.org/svn/reactos?rev=52226&view=rev
Log:
[FREELDR]
Start implementing a realmode callback mechanism
Added:
trunk/reactos/boot/freeldr/freeldr/arch/realmode/int386.inc
Modified:
trunk/reactos/boot/freeldr/freeldr/arch/i386/entry.S
trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S
trunk/reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h
Modified: trunk/reactos/boot/freeldr/freeldr/arch/i386/entry.S
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/i386/entry.S?rev=52226&r1=52225&r2=52226&view=diff
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/i386/entry.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/freeldr/arch/i386/entry.S [iso-8859-1] Tue Jun 14 12:17:28 2011
@@ -44,9 +44,9 @@
lidt i386idtptr
/* Continue execution */
- jmp dword ptr [_ContinueAddress]
-
-_ContinueAddress:
+ jmp dword ptr [ContinueAddress]
+
+ContinueAddress:
.long _FrldrStartup
@@ -58,6 +58,12 @@
mov dword ptr [_FrldrBootDrive], eax
mov al, dh
mov dword ptr [_FrldrBootPartition], eax
+
+ /* Patch long jump with real mode entry point */
+ mov eax, dword ptr ds:[BSS_RealModeEntry]
+ mov dword ptr ds:[SwitchToReal16Address], eax
+
+call _Int386_ // test
/* GO! */
xor eax, eax
@@ -215,6 +221,51 @@
PUBLIC _EnableA20
_EnableA20:
ret
+
+PUBLIC _Int386_
+_Int386_:
+ /* Save all registers + segment registers */
+ push ds
+ push es
+ push fs
+ push gs
+ pusha
+
+ /* Set the callback index */
+ mov cx, 1234
+
+ /* Set continue address and switch to real mode */
+ mov dword ptr [ContinueAddress], offset Int386_return
+ jmp SwitchToReal
+
+Int386_return:
+
+ popa
+ pop gs
+ pop fs
+ pop es
+ pop ds
+ ret
+
+
+SwitchToReal:
+ /* Set sane segments */
+ mov ax, PMODE_DS
+ mov ds, ax
+ mov es, ax
+ mov fs, ax
+ mov gs, ax
+ mov ss, ax
+
+ /* Save 32-bit stack pointer */
+ mov dword ptr [stack32], esp
+
+ /* jmp to 16-bit segment to set the limit correctly */
+ .byte HEX(0ea) // jmp far RMODE_CS:switch_to_real16
+SwitchToReal16Address:
+ .long 0 // receives address of switch_to_real16
+ .word RMODE_CS
+ nop
/* Multiboot support
Modified: trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S?rev=52226&r1=52225&r2=52226&view=diff
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/freeldr/arch/realmode/i386.S [iso-8859-1] Tue Jun 14 12:17:28 2011
@@ -30,6 +30,9 @@
/* Enable A20 address line */
call EnableA20
+ /* Safe real mode entry point in shared memory */
+ mov dword ptr [BSS_RealModeEntry], offset switch_to_real16
+
/* Get address of optional header */
mov eax, dword ptr ds:[FREELDR_PE_BASE + IMAGE_DOS_HEADER_e_lfanew]
add eax, FREELDR_PE_BASE + 4 + IMAGE_FILE_HEADER_SIZE
@@ -38,20 +41,74 @@
mov eax, dword ptr ds:[eax + IMAGE_OPTIONAL_HEADER_AddressOfEntryPoint]
add eax, FREELDR_PE_BASE
- /* Safe the entry point */
- mov dword ptr [BSS_EntryPoint], eax
-
/* Patch the long jump instruction */
mov word ptr [pm_offset], ax
+
+ jmp exit_to_protected
+
+
+/* This is the entry point from protected mode */
+switch_to_real16:
+
+ /* Restore segment registers to correct limit */
+ mov ax, RMODE_DS
+ mov ds, ax
+ mov es, ax
+ mov fs, ax
+ mov gs, ax
+ mov ss, ax
+
+ /* Disable Protected Mode */
+ mov eax, cr0
+ and eax, CR0_PE_CLR
+ mov cr0, eax
+
+ /* Clear prefetch queue & correct CS */
+ ljmp16 0, inrmode
+
+inrmode:
+ /* Set real mode segments */
+ xor ax, ax
+ mov ds, ax
+ mov es, ax
+ mov fs, ax
+ mov gs, ax
+ mov ss, ax
+
+ /* Clear out the high 16-bits of ESP */
+ /* This is needed because I have one */
+ /* machine that hangs when booted to dos if */
+ /* anything other than 0x0000 is in the high */
+ /* 16-bits of ESP. Even though real-mode */
+ /* code should only use SP and not ESP. */
+ xor esp, esp
+
+ /* Restore real mode stack */
+ mov sp, word ptr ds:[stack16]
+
+ /* Load IDTR with real mode value */
+ lidt rmode_idtptr
+
+ sti /* These are ok now */
+
+ /* Do the callback, specified by cx */
+ // call word ptr CallbackTable[cx * 4]
+ mov ax, cx
+ call writehex4
/*
* Switches the processor to protected mode
* it destroys eax
*/
-switch_to_prot:
+exit_to_protected:
+
+ cli
+
+ /* Safe current stack pointer */
+ mov word ptr ds:[stack16], sp
/* Load the GDT */
- lgdt gdtptr
+ lgdt gdtptr
/* Enable Protected Mode */
mov eax, cr0
@@ -64,6 +121,7 @@
.word 0 // receives address of PE entry point
.word PMODE_CS
nop
+
@@ -109,8 +167,14 @@
.word HEX(27) /* Limit */
.long gdt /* Base Address */
-.org 1024
+/* Real-mode IDT pointer */
+rmode_idtptr:
+ .word HEX(3ff) /* Limit */
+ .long 0 /* Base Address */
+//.org 1024
+
+#include "int386.inc"
#include "helpers.inc"
.org (FREELDR_PE_BASE - FREELDR_BASE)
Added: trunk/reactos/boot/freeldr/freeldr/arch/realmode/int386.inc
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arch/realmode/int386.inc?rev=52226&view=auto
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arch/realmode/int386.inc (added)
+++ trunk/reactos/boot/freeldr/freeldr/arch/realmode/int386.inc [iso-8859-1] Tue Jun 14 12:17:28 2011
@@ -1,0 +1,57 @@
+
+
+Int386:
+ /* Get the interupt vector and patch the opcode */
+ mov al, byte ptr ds:[BSS_IntVector]
+ mov byte ptr ds:[Int386_vector_opcode], al
+
+ /* Setup the registers */
+ mov ax, word ptr cs:[BSS_RegisterSet + REGS_DS]
+ mov ds, ax /* DS register */
+ mov ax, word ptr cs:[BSS_RegisterSet + REGS_ES]
+ mov es, ax /* ES register */
+ mov ax, word ptr cs:[BSS_RegisterSet + REGS_FS]
+ mov fs, ax /* FS register */
+ mov ax, word ptr cs:[BSS_RegisterSet + REGS_GS]
+ mov gs, ax /* GS register */
+
+ mov eax, dword ptr cs:[BSS_RegisterSet + REGS_EAX] /* EAX register */
+ mov ebx, dword ptr cs:[BSS_RegisterSet + REGS_EBX] /* EBX register */
+ mov ecx, dword ptr cs:[BSS_RegisterSet + REGS_ECX] /* ECX register */
+ mov edx, dword ptr cs:[BSS_RegisterSet + REGS_EDX] /* EDX register */
+ mov esi, dword ptr cs:[BSS_RegisterSet + REGS_ESI] /* ESI register */
+ mov edi, dword ptr cs:[BSS_RegisterSet + REGS_EDI] /* EDI register */
+
+ /* Do not set the flags register */
+ /* only return its value in regsout */
+
+ /* Call the interrupt vector */
+ /*int Int386_vector*/
+ .byte 0xcd
+Int386_vector_opcode:
+ .byte 0x00
+
+ /* Save the registers */
+ mov dword ptr cs:[BSS_RegisterSet + REGS_EAX], eax /* EAX register */
+ mov dword ptr cs:[BSS_RegisterSet + REGS_EBX], ebx /* EBX register */
+ mov dword ptr cs:[BSS_RegisterSet + REGS_ECX], ecx /* ECX register */
+ mov dword ptr cs:[BSS_RegisterSet + REGS_EDX], edx /* EDX register */
+ mov dword ptr cs:[BSS_RegisterSet + REGS_ESI], esi /* ESI register */
+ mov dword ptr cs:[BSS_RegisterSet + REGS_EDI], edi /* EDI register */
+
+ mov ax, ds /* DS register */
+ mov word ptr cs:[BSS_RegisterSet + REGS_DS], ax
+ mov ax, es /* ES register */
+ mov word ptr cs:[BSS_RegisterSet + REGS_ES], ax
+ mov ax, fs /* FS register */
+ mov word ptr cs:[BSS_RegisterSet + REGS_FS], ax
+ mov ax, gs /* GS register */
+ mov word ptr cs:[BSS_RegisterSet + REGS_GS], ax
+
+ pushf
+ pop dword ptr cs:[BSS_RegisterSet + REGS_EFLAGS] /* EFLAGS register */
+
+ ret
+
+
+
Modified: trunk/reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h?rev=52226&r1=52225&r2=52226&view=diff
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/freeldr/include/arch/pc/x86common.h [iso-8859-1] Tue Jun 14 12:17:28 2011
@@ -17,11 +17,26 @@
#define DISKREADBUFFER_SIZE 512
/* These addresses specify the realmode "BSS section" layout */
-#define BSS_EntryPoint (BSS_START + 0)
+#define BSS_RealModeEntry (BSS_START + 0)
#define BSS_CallbackAddress (BSS_START + 4)
#define BSS_CallbackReturn (BSS_START + 8)
-#define BSS_BootDrive (BSS_START + 12)
-#define BSS_BootPartition (BSS_START + 16)
+
+#define BSS_RegisterSet (BSS_START + 16) /* size = 36 */
+#define BSS_IntVector (BSS_START + 52)
+// next 52
+
+/* Layout of the REGS structure */
+#define REGS_EAX 0
+#define REGS_EBX 4
+#define REGS_ECX 8
+#define REGS_EDX 12
+#define REGS_ESI 16
+#define REGS_EDI 20
+#define REGS_DS 24
+#define REGS_ES 26
+#define REGS_FS 28
+#define REGS_GS 30
+#define REGS_EFLAGS 32
// Flag Masks
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