Preliminary support for CHS disks.

bochsrc

@@ -11,7 +11,7 @@ floppy_bootsig_check: disabled=0
 floppya: type=none
 # no floppyb
 ata0: enabled=true, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
-ata0-master: type=disk, path="virtdisk.bin", mode=flat, cylinders=2, heads=16, spt=63, sect_size=512, model="Generic 1234", biosdetect=auto, translation=auto
+ata0-master: type=disk, path="virtdisk.bin", mode=flat, cylinders=8, heads=16, spt=63, sect_size=512, model="Generic 1234", biosdetect=auto, translation=auto
 ata0-slave: type=none
 ata1: enabled=true, ioaddr1=0x170, ioaddr2=0x370, irq=15
 ata1-master: type=none

boot.nasm

@@ -23,14 +23,14 @@ add word [addr_packet_transfer_buff_seg], (secreadcnt*512)/16
 add word [addr_packet_start_block], secreadcnt
 loop read_loop
 entry:
-mov ax,0x2403 ; A20 BIOS Support
+;mov ax,0x2403 ; A20 BIOS Support
-int 0x15
+;int 0x15
-jb .no_a20
+;jb .no_a20
-cmp ah,0
+;cmp ah,0
-jnz .no_a20
+;jnz .no_a20
-mov ax,0x2401 ; A20 BIOS Activate
+;mov ax,0x2401 ; A20 BIOS Activate
-int 0x15
+;int 0x15
-.no_a20:
+;.no_a20:
 cli             ; no interrupts
 xor ax,ax
 mov ds, ax
@@ -39,15 +39,41 @@ mov eax, cr0    ; set pmode bit
 or al, 1
 mov cr0, eax
 jmp 08h:Pmode
+no_exten:
+; read with CHS
+; FIXME This only reads up to sector count
+mov ah,8
+int 0x13 ; geometry
+and cx, 0x3f
+push cx
+push 0x0080 ; DH=head,DL=disk
+push 0x2000 ; buffer seg
+push 2 ; sector
+.loop:
+mov ax, [esp]
+push 0xb800
+pop es
+xor di,di
+call hexprint
+mov ax, [esp+2]
+mov es, ax
+mov ax, 0x0201
+mov cx, [esp]
+xor bx,bx
+mov dx, [esp+4]
+int 0x13
+jc err
+add word [esp+2], 0x20
+mov cx, [esp]
+inc cl
+mov [esp], cx
+cmp cl, [esp+6]
+jg entry
+jmp .loop
 err:
 mov bx, ax
 mov si, string
 mov cx, string_end - string
-jmp print
-no_exten:
-mov bx, ax
-mov si, no_exten_str
-mov cx, no_exten_str_end - no_exten_str
 print:
 push 0xb800
 pop es
@@ -57,9 +83,9 @@ err_print:
 lodsb
 stosw
 loop err_print
-add di, 2
+;add di, 2
-mov ax, bx
+;mov ax, bx
-call hexprint
+;call hexprint
 hlt_loop:
 hlt
 jmp hlt_loop
@@ -100,20 +126,57 @@ mov [esi], esi
 mov [edi], edi
 cmpsd
 jne .kernel
-in al, 0x92 ; fast A20
+call enable_A20
-test al, 2
+;in al, 0x92 ; fast A20
-jnz .fa20_end
+;test al, 2
-or al, 2
+;jnz .fa20_end
-and al, 0xFE
+;or al, 2
-out 0x92, al
+;and al, 0xFE
-.fa20_end:
+;out 0x92, al
+;.fa20_end:
 jmp .a20
 .kernel:
-mov esi, 0x8000
+;mov dword [0xb8000], 0x07000700 | 'P' | 'M' << 16
+;mov dword [0xb8004], 0x07000700 | 'O' | 'D' << 16
+;mov dword [0xb8008], 0x07000700 | 'E' | ' ' << 16
+mov esi, 0x20000
 mov edi, 0x100000
 mov ecx, 0x10000
 rep movsb
 jmp 08h:0x100000
+enable_A20:
+        cli
+        call    a20wait
+        mov     al,0xAD
+        out     0x64,al
+        call    a20wait
+        mov     al,0xD0
+        out     0x64,al
+        call    a20wait2
+        in      al,0x60
+        push    eax
+        call    a20wait
+        mov     al,0xD1
+        out     0x64,al
+        call    a20wait
+        pop     eax
+        or      al,2
+        out     0x60,al
+        call    a20wait
+        mov     al,0xAE
+        out     0x64,al
+        call    a20wait
+        ret
+a20wait:
+        in      al,0x64
+        test    al,2
+        jnz     a20wait
+        ret
+a20wait2:
+        in      al,0x64
+        test    al,1
+        jz      a20wait2
+        ret
 
 gdt_desc:
     dw gdt_end - gdt
@@ -134,12 +197,12 @@ gdt_end:
 
 string: db 'DISK ERROR'
 string_end:
-no_exten_str: db 'NO INT13 EXTEN'
+;no_exten_str: db 'NO INT13 EXTEN'
-no_exten_str_end:
+;no_exten_str_end:
 
 addr_packet:
 db 0x10, 0x00 ; size, reserved
 dw secreadcnt ; blocks
 addr_packet_transfer_buff_off: dw 0x0000 ; transfer buffer offset
-addr_packet_transfer_buff_seg: dw 0x0800 ; transfer buffer segment
+addr_packet_transfer_buff_seg: dw 0x2000 ; transfer buffer segment
 addr_packet_start_block: dq 1 ; start block

dosfs/dosfs.c

@@ -11,7 +11,17 @@
 #include "dosfs.h"
 #include "tmpstring.c"
 #include "../v86defs.h"
+#include "../print.h"
 
+extern uint32_t _gpf_eax_save;
+extern uint32_t _gpf_eflags_save;
+extern uint16_t error_screen[80*50]; // defined in kernel.c
+__attribute((__no_caller_saved_registers__))
+extern void error_environment(); // defined in kernel.c
+uint32_t numHead;
+uint32_t secPerTrack;
+uint32_t maxCylinder;
+char useCHS = -1;
 uint32_t DFS_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
 	// NOTE If the buffer provided is outside the 0x20000-0x2FE00 range,
 	// the function will use that buffer for the Virtual 8086 process
@@ -19,6 +29,38 @@ uint32_t DFS_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t
 	uint8_t *v86buf = buffer;
 	if ((uintptr_t)v86buf < 0x20000 || (uintptr_t)v86buf > 0x2FE00)
 		v86buf = (uint8_t *)0x20000;
+
+	// TODO This check should probably happen at the kernel level
+	if (useCHS == -1) {
+		union V86Regs_t regs;
+		// Check for INT 13 Extensions support
+		regs.h.ah = 0x41;
+		regs.w.bx = 0x55AA;
+		regs.h.dl = 0x80;
+		V8086Int(0x13, &regs);
+		// LBA supported if CF clear
+		if (!(_gpf_eflags_save & 0x1)) {
+			useCHS = 0;
+		} else {
+			FARPTR v86_entry = i386LinearToFp(v86DiskGetGeometry);
+			enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+			// check CF for error
+			if (_gpf_eflags_save & 0x1) {
+				uint16_t *vga = error_screen;
+				vga += printStr("Could not get Disk Geometry.", vga);
+				error_environment();
+				for(;;);
+			}
+			numHead = ((_gpf_eax_save & 0xff00) >> 8) + 1;
+			secPerTrack = _gpf_eax_save & 0x3f;
+			maxCylinder = ((_gpf_eax_save & 0xff0000) >> 16) | ((_gpf_eax_save & 0xc0) << 2);
+			useCHS = 1;
+		}
+	}
+
+	// TODO Do error handling
+	if (!useCHS) {
+		// LBA Read
 		v86disk_addr_packet.start_block = sector;
 		v86disk_addr_packet.blocks = count;
 		v86disk_addr_packet.transfer_buffer =
@@ -27,6 +69,21 @@ uint32_t DFS_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t
 		union V86Regs_t regs;
 		FARPTR v86_entry = i386LinearToFp(v86DiskRead);
 		enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+	} else {
+        uint32_t tmp = sector / secPerTrack;
+        uint32_t sec = (sector % (secPerTrack)) + 1;
+        uint32_t head = tmp % numHead;
+        uint32_t cyl = tmp / numHead;
+		union V86Regs_t regs;
+        regs.w.ax = 0x0201;
+        regs.h.ch = cyl & 0xff;
+        regs.h.cl = sec | ((cyl >> 2) & 0xc0);
+        regs.h.dh = head;
+        regs.h.dl = 0x80;
+        regs.w.bx = (uintptr_t)v86buf & 0xFFFF;
+        FARPTR v86_entry = i386LinearToFp(v86DiskReadCHS);
+        enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+	}
 	if (v86buf != buffer)
 		memcpy(buffer, v86buf, count * SECTOR_SIZE);
 	return 0;

entry.nasm

@@ -1,5 +1,8 @@
 global entry
 entry:
+mov dword [0xb8000], 0x07000700 | 'E' | 'N' << 16
+mov dword [0xb8004], 0x07000700 | 'T' | 'R' << 16
+mov dword [0xb8008], 0x07000700 | 'Y' | ' ' << 16
 lgdt [gdt_desc]  ; load gdt register
 jmp 08h:Pmodecode
 
@@ -19,9 +22,19 @@ mov eax, 0x1f001f00
 mov ecx, (80*25)/2
 mov edi, 0xb8000
 rep stosd ; clear screen
+mov eax, dword [kernel_check]
+cmp eax, 0x12345678
+jne err
 call start
 hlt_loop:
 hlt
 jmp hlt_loop
+err:
+mov dword [0xb8000], 0x07000700 | 'L' | 'O' << 16
+mov dword [0xb8004], 0x07000700 | 'A' | 'D' << 16
+mov dword [0xb8008], 0x07000700 | 'F' | 'A' << 16
+mov dword [0xb800C], 0x07000700 | 'I' | 'L' << 16
+jmp hlt_loop
 
 extern start
+extern kernel_check

fault.nasm

@@ -24,6 +24,8 @@ jmp .hlt
 
 global _gpf_eax_save
 _gpf_eax_save: dd 0
+global _gpf_eflags_save
+_gpf_eflags_save: dd 0
 extern gpf_handler_v86
 global gpfHandler
 gpfHandler:
@@ -52,6 +54,7 @@ pop ecx
 pop ebx
 sti ; we shouldn't crash now?
 mov eax, dword [esp+16] ; EFLAGS
+mov dword [_gpf_eflags_save], eax ; save
 and eax, 1 << 17 ; VM flag
 test eax, eax
 pop eax

kernel.c

@@ -297,6 +297,7 @@ void FileSelect() {
     }
 }
 
+uint32_t kernel_check= 0x12345678;
 void start() {
     word *vga_text = (word *)0xb8000;
     char h[] = "LuciaOS";

link.ld

@@ -4,11 +4,11 @@ ENTRY(entry)
 SECTIONS {
     . = 0x100000;
 
-    .text : ALIGN(0x1000) {
+    .text : {
         *(.text);
     }
 
-    .data : ALIGN(0x1000) {
+    .data : {
         *(.data);
         *(.rodata);
         *(.rodata*);

tests.c

@@ -34,23 +34,74 @@ char TestUser() {
     return 0;
 }
 void TestDiskRead() {
+    //vga_text += printStr("Starting Disk Read... ", vga_text);
     union V86Regs_t regs;
-    uint16_t *vga_text = (uint16_t *)0xb8000 + (80*5);
-    vga_text += printStr("Setting Text Mode... ", vga_text);
-    regs.w.ax = 3; // text mode
-    V8086Int(0x10, &regs); 
-    //vga_text += printStr("Done. Starting Disk Read... ", vga_text);
     char *diskReadBuf = (char *)0x20000;
 	v86disk_addr_packet.transfer_buffer =
 		(uintptr_t)diskReadBuf & 0x000F |
 		(((uintptr_t)diskReadBuf & 0xFFFF0) << 12);
     FARPTR v86_entry = i386LinearToFp(v86DiskRead);
     enter_v86(0x0000, 0x8000, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
-    vga_text = (uint16_t *)0xb8000;
+    uint16_t *vga_text = (uint16_t *)0xb8000;
     for (int i = 0; i < (80*25)/2; i++) {
         printByte(diskReadBuf[i], &vga_text[i*2]);
     }
 }
+extern uint32_t _gpf_eax_save;
+extern uint32_t _gpf_eflags_save;
+void TestCHS() {
+    uint16_t *vga_text = (uint16_t*)0xb8000;
+    printStr("CHS Test ", vga_text);
+    // CHS Read
+    union V86Regs_t regs;
+    FARPTR v86_entry = i386LinearToFp(v86DiskGetGeometry);
+    enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+    // check CF for error
+    if (_gpf_eflags_save & 0x1) {
+        uint16_t *vga = &((uint16_t*)0xb8000)[80];
+        vga += printStr("Could not get Disk Geometry.", vga);
+        return;
+    }
+    uint32_t numHead = ((_gpf_eax_save & 0xff00) >> 8) + 1;
+    uint32_t secPerTrack = _gpf_eax_save & 0x3f;
+    uint32_t maxCyl = ((_gpf_eax_save & 0xff0000) >> 16) | ((_gpf_eax_save & 0xc0) << 2);
+    uint32_t maxLBA = numHead * secPerTrack * (maxCyl + 1);
+    for (uint32_t sector = 0; sector < maxLBA && sector < 0x8000 /* don't bother reading huge disks */; sector += (sector + secPerTrack < maxLBA) ? secPerTrack : 1) {
+        uint16_t *vga = &((uint16_t*)0xb8000)[9];
+        vga += printWord(sector, vga); vga++;
+        // LBA -> CHS
+        uint32_t tmp = sector / secPerTrack;
+        uint32_t sec = (sector % (secPerTrack)) + 1;
+        uint32_t head = tmp % numHead;
+        uint32_t cyl = tmp / numHead;
+        vga += printWord(cyl, vga); vga += printChar(':', vga);
+        vga += printByte(head, vga); vga += printChar(':', vga);
+        vga += printByte(sec, vga); vga += printChar(' ', vga);
+        vga += printStr("/ ", vga);
+        vga += printWord(maxCyl, vga); vga += printChar(':', vga);
+        vga += printByte(numHead - 1, vga); vga += printChar(':', vga);
+        vga += printByte(secPerTrack, vga); vga += printChar(' ', vga);
+        regs.w.ax = 0x0201;
+        regs.h.ch = cyl & 0xff;
+        regs.h.cl = sec | ((cyl >> 2) & 0xc0);
+        regs.h.dh = head;
+        regs.h.dl = 0x80;
+        regs.w.bx = 0x0000;
+        v86_entry = i386LinearToFp(v86DiskReadCHS);
+        enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+        // if CF was set, we have error
+        if (_gpf_eflags_save & 0x1) {
+            uint16_t *vga = &((uint16_t*)0xb8000)[80];
+            vga += printStr("Disk Error: ", vga);
+            vga += printByte(_gpf_eax_save & 0xff, vga);
+            vga += printStr(" CHS=", vga);
+            vga += printWord(cyl, vga); vga += printChar(':', vga);
+            vga += printByte(head, vga); vga += printChar(':', vga);
+            vga += printByte(sec, vga);
+            return;
+        }
+    }
+}
 void TestFAT() {
     uint16_t *vga_text = (uint16_t *)0xb8000;
     uint8_t *diskReadBuf = (uint8_t *)0x22400;
@@ -144,6 +195,13 @@ void RunTests() {
         vga_text += printStr("Usermode test failed! Press any key to continue.", vga_text);
     }
     kbd_wait();
+    union V86Regs_t regs;
+    vga_text = (uint16_t *)0xb8000 + (80*5);
+    vga_text += printStr("Setting Text Mode... ", vga_text);
+    regs.w.ax = 3; // text mode
+    V8086Int(0x10, &regs); 
+    TestCHS();
+    kbd_wait();
     TestDiskRead();
     kbd_wait();
     TestFAT();

v86.nasm

@@ -108,3 +108,23 @@ db 0x10, 0x00 ; size, reserved
 dw 0x1 ; blocks
 dd 0x23000000 ; transfer buffer 0x23000
 dq 0x1 ; start block
+
+global v86DiskGetGeometry
+v86DiskGetGeometry:
+mov ah, 8
+mov dl, 0x80
+int 0x13
+movzx eax, ch
+shl eax, 16
+mov al, cl
+mov ah, dh
+int 0x30
+ud2
+
+global v86DiskReadCHS
+v86DiskReadCHS:
+push 0x2000
+pop es
+int 0x13
+int 0x30
+ud2

v86defs.h

@@ -9,6 +9,8 @@ extern void v86TransFlag();
 extern void v86Interrupt();
 extern void v86TextMode();
 extern void v86DiskRead();
+extern void v86DiskGetGeometry();
+extern void v86DiskReadCHS();
 
 union __attribute((__packed__)) V86Regs_t {
     struct dword_regs {