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Moved INT 13H disk operations outside DOSFS driver

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This commit is contained in:
Lucia Ceionia 2023-02-09 13:19:50 -06:00
parent c7b69675bb
commit 094e278212
7 changed files with 153 additions and 97 deletions
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2
Makefile
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@ -1,4 +1,4 @@
objects = entry.o kernel.o task.o handler.o interrupt.o v86.o print.o tss.o dosfs/dosfs.o gdt.o usermode.o paging.o fault.o tests.o kbd.o helper.o progs.o
objects = entry.o kernel.o task.o handler.o interrupt.o v86.o print.o tss.o dosfs/dosfs.o gdt.o usermode.o paging.o fault.o tests.o kbd.o helper.o progs.o disk.o
CFLAGS = -target "i686-elf" -m32 -mgeneral-regs-only -ffreestanding -march=i686 -fno-stack-protector -Wno-int-conversion -nostdlib -c
%.o: %.nasm

121
disk.c Normal file
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@ -0,0 +1,121 @@
#include "v86defs.h"
#include "print.h"
#include "dosfs/dosfs.h"
#include "stdint.h"
extern void *memcpy(void *restrict dest, const void *restrict src, uintptr_t n);
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;
void Disk_SetupCHS() {
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;
}
}
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
// and copy to the other buffer after
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) {
Disk_SetupCHS();
}
// TODO Do error handling
if (!useCHS) {
// LBA Read
v86disk_addr_packet.start_block = sector;
v86disk_addr_packet.blocks = count;
v86disk_addr_packet.transfer_buffer =
(uintptr_t)v86buf & 0x000F |
(((uintptr_t)v86buf & 0xFFFF0) << 12);
union V86Regs_t regs;
regs.h.ah = 0x42;
FARPTR v86_entry = i386LinearToFp(v86DiskOp);
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;
}
uint32_t DFS_WriteSector(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 copy that buffer into the Virtual 8086 disk range
uint8_t *v86buf = buffer;
if ((uintptr_t)v86buf < 0x20000 || (uintptr_t)v86buf > 0x2FE00) {
v86buf = (uint8_t *)0x20000;
memcpy(v86buf, buffer, count * SECTOR_SIZE);
}
// TODO This check should probably happen at the kernel level
if (useCHS == -1) {
Disk_SetupCHS();
}
// TODO Do error handling
if (!useCHS) {
// LBA Read
v86disk_addr_packet.start_block = sector;
v86disk_addr_packet.blocks = count;
v86disk_addr_packet.transfer_buffer =
(uintptr_t)v86buf & 0x000F |
(((uintptr_t)v86buf & 0xFFFF0) << 12);
union V86Regs_t regs;
regs.w.ax = 0x4300;
FARPTR v86_entry = i386LinearToFp(v86DiskOp);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
} else {
uint16_t *vga = error_screen;
vga += printStr("CHS Write Unimplemented", vga);
error_environment();
for(;;);
}
return 0;
}

84
dosfs/dosfs.c
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@ -1,3 +1,5 @@
#include "tmpstring.c"
/*
DOSFS Embedded FAT-Compatible Filesystem
(C) 2005 Lewin A.R.W. Edwards (sysadm@zws.com)
@ -9,88 +11,6 @@
*/
#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
// and copy to the other buffer after
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 =
(uintptr_t)v86buf & 0x000F |
(((uintptr_t)v86buf & 0xFFFF0) << 12);
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;
}
uint32_t DFS_WriteSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
for(;;);
}
/*
Get starting sector# of specified partition on drive #unit

29
kernel.c
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@ -239,6 +239,16 @@ void PrintFileList() {
char IsDir(DIRENT *de) {
return de->attr & ATTR_DIRECTORY;
}
void ScancodeTest() {
uint16_t *vga = (uint16_t*)0xb8000;
uint16_t scancode;
while(((scancode = get_scancode()) & 0xff) != KEY_F1) {
vga += printWord(scancode, vga);
vga++;
if ((uintptr_t)vga >= 0xb8000+80*25*2)
vga = (uint16_t*)0xb8000;
}
}
extern void create_child(uint32_t esp, uint32_t eip, uint32_t argc, ...);
void FileSelect() {
uint8_t current_path[80];
@ -255,15 +265,15 @@ void FileSelect() {
// Info line (4)
{
uint16_t *vga = &vga_text[80*4 + 79 - 24];
printStr("T to run tests", vga);
vga += 80;
printStr("X to view in hex", vga);
vga += 80;
printStr("V to view as text", vga);
printStr("T to view as text", vga);
vga += 80;
printStr("P to load as program", vga);
vga += 80;
printStr("O to open directory", vga);
vga += 80;
printStr("F4 to run tests", vga);
}
printStr((char*)current_path, &vga_text[80*4 + 2]);
for (int i = 2; i < 15; i++)
@ -285,15 +295,15 @@ void FileSelect() {
uint16_t key = get_scancode();
uint8_t path[13];
switch (key & 0xff) { // scancode component
case 0x50: // down
case KEY_DOWN: // down
fileHovered++;
if (fileHovered >= fileCount) fileHovered = 0;
break;
case 0x48: // up
case KEY_UP: // up
fileHovered--;
if (fileHovered < 0) fileHovered = fileCount - 1;
break;
case 0x14: // t
case KEY_F4:
create_child(0x380000, (uintptr_t)RunTests, 0);
SetCursorDisabled();
reload = 1;
@ -313,7 +323,7 @@ void FileSelect() {
SetCursorDisabled();
reload = 1;
break;
case KEY_V:
case KEY_T:
File83ToPath((char*)entries[fileHovered].name, (char*)&current_path[current_path_end]);
//TextViewTest(path, &vi);
create_child(0x380000, (uintptr_t)TextViewTest, 2, current_path, &vi);
@ -322,6 +332,7 @@ void FileSelect() {
reload = 1;
break;
case KEY_O:
case 0x9C: // enter release
if (IsDir(&entries[fileHovered])) {
uint8_t tmp_path[80];
File83ToPath((char*)entries[fileHovered].name, (char*)tmp_path);
@ -346,6 +357,10 @@ void FileSelect() {
fileHovered = 0;
}
break;
case KEY_F6:
ScancodeTest();
reload = 1;
break;
default:
break;
}

3
tests.c
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@ -40,7 +40,8 @@ void TestDiskRead() {
v86disk_addr_packet.transfer_buffer =
(uintptr_t)diskReadBuf & 0x000F |
(((uintptr_t)diskReadBuf & 0xFFFF0) << 12);
FARPTR v86_entry = i386LinearToFp(v86DiskRead);
regs.h.ah = 0x42;
FARPTR v86_entry = i386LinearToFp(v86DiskOp);
enter_v86(0x0000, 0x8000, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
uint16_t *vga_text = (uint16_t *)0xb8000;
for (int i = 0; i < (80*25)/2; i++) {

9
v86.nasm
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@ -89,11 +89,10 @@ int 0x10
int 0x30
jmp $
global v86DiskRead
v86DiskRead:
xor ax, ax ; TODO fix assuming we're in first 64k
mov ds, ax
mov ah, 0x42
global v86DiskOp
v86DiskOp:
xor bx, bx ; TODO fix assuming we're in first 64k
mov ds, bx
mov dl, 0x80 ; TODO get this from BIOS or something
mov si, v86disk_addr_packet ; ds:si
int 0x13

2
v86defs.h
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@ -8,7 +8,7 @@ extern void v86Test();
extern void v86TransFlag();
extern void v86Interrupt();
extern void v86TextMode();
extern void v86DiskRead();
extern void v86DiskOp();
extern void v86DiskGetGeometry();
extern void v86DiskReadCHS();