Can create usermode children, Can load programs from disk

.gitignore

@@ -1,4 +1,5 @@
 *.o
 *.bin
 *.lock
+*.com
 bx_enh_dbg.ini

fault.nasm

@@ -57,6 +57,7 @@ jmp _fault_coda
 
 _gpf_old_ds: dw 0
 extern get_key
+extern get_scancode
 extern task_ptr
 extern _enter_v86_internal_no_task
 extern return_prev_task
@@ -76,7 +77,11 @@ cmp al, 0x00 ; get key
 jne .s1
 call get_key
 jmp .return_to_offender
-.s1: cmp al, 0x86 ; v86 interrupt call
+.s1: cmp al, 0x01 ; get scancode
+jne .s86
+call get_scancode
+jmp .return_to_offender
+.s86: cmp al, 0x86 ; v86 interrupt call
 jne .return_to_offender
 add esp, 4
 add dword [esp+0], 2

kernel.c

@@ -219,7 +219,7 @@ void FileSelect() {
     int32_t fileHovered = 0, lastFileHovered = 0;
     for (char reload = 1;;) {
         // Info line (4)
-        printStr("T to run tests - X to view in hex - V to view as text", &vga_text[80*4+2]);
+        printStr("T to run tests - X to view in hex - V to view as text - P to load as program", &vga_text[80*4+2]);
         VOLINFO vi; DIRINFO di;
         if (reload) {
             OpenVol(&vi);
@@ -250,6 +250,14 @@ void FileSelect() {
                 DrawScreen();
                 reload = 1;
                 break;
+            case KEY_P:
+                File83ToPath((char*)entries[fileHovered].name, (char*)path);
+                create_child(0x380000, (uintptr_t)ProgramLoadTest, 2, path, &vi);
+                SetVideo25Lines();
+                SetCursorDisabled();
+                DrawScreen();
+                reload = 1;
+                break;
             case KEY_X:
                 File83ToPath((char*)entries[fileHovered].name, (char*)path);
                 //HexViewTest(path, &vi);

progs.c

@@ -1,4 +1,6 @@
 #include "progs.h"
+#include "helper.h"
+#include "kbd.h"
 
 void HexViewTest(uint8_t *path, VOLINFO *vi) {
     uint32_t err;
@@ -309,3 +311,62 @@ void TextViewTest(uint8_t *path, VOLINFO *vi) {
         }
     }
 }
+// 400000 - 700000 Usermode Code (3mB)
+// 700000 - 800000 Usermode Stack (1mB)
+extern uint32_t create_user_child(uint32_t esp, uint32_t eip, uint32_t argc, ...);
+void ProgramLoadTest(uint8_t *path, VOLINFO *vi) {
+    uint16_t *vga_text = (uint16_t *)0xb8000;
+    for (int i = 0; i < 80*25; i++)
+        vga_text[i] = 0x0f00;
+    uint32_t successcount;
+    uint8_t *diskReadBuf = (uint8_t *)0x400000;
+    {
+        uint32_t err;
+        uint8_t *scratch = (uint8_t *)0x20000;
+        FILEINFO fi;
+        err = DFS_OpenFile(vi, path, DFS_READ, scratch, &fi);
+        if (err) {
+            vga_text += printStr("Open Error: ", vga_text);
+            printDword(err, vga_text);
+            return;
+        }
+        if (fi.filelen > 0x300000) {
+            vga_text += printStr("File too large.", vga_text);
+            kbd_wait();
+            return;
+        }
+        DFS_Seek(&fi, 0, scratch);
+        if (fi.pointer != 0) {
+            vga_text += printStr("Seek Error", vga_text);
+            return;
+        }
+        err = DFS_ReadFile(&fi, scratch, diskReadBuf, &successcount, fi.filelen);
+        if (err && err != DFS_EOF) {
+            vga_text += printStr("Read Error: ", vga_text);
+            printDword(err, vga_text);
+            return;
+        }
+        if (successcount < fi.filelen) {
+            vga_text += printStr("Could not read all file bytes.", vga_text);
+            return;
+        }
+    }
+    vga_text += printStr("Successfully loaded program \"", vga_text);
+    vga_text += printStr((char*)path, vga_text);
+    vga_text += printStr("\", ", vga_text);
+    vga_text += printDec(successcount, vga_text);
+    vga_text += printStr(" Bytes.", vga_text);
+    vga_text = nextLine(vga_text);
+    vga_text += printStr("Press any key to run.", vga_text);
+    kbd_wait();
+    uint32_t res = create_user_child(0x800000, 0x400000, 0);
+    vga_text = (uint16_t *)0xb8000;
+    for (int i = 0; i < 80*25; i++)
+        vga_text[i] = 0x0f00;
+    vga_text += printStr("Program returned code: ", vga_text);
+    vga_text += printDec(res, vga_text);
+    vga_text += printStr(" (0x", vga_text);
+    vga_text += printDword(res, vga_text);
+    vga_text += printStr("). Press any key to exit.", vga_text);
+    kbd_wait();
+}

progs.h

@@ -9,3 +9,4 @@
 
 void HexViewTest(uint8_t *path, VOLINFO *vi);
 void TextViewTest(uint8_t *path, VOLINFO *vi);
+void ProgramLoadTest(uint8_t *path, VOLINFO *vi);

task.nasm

@@ -11,7 +11,6 @@ task_ptr: equ (0x310000-4)
 ; extern void create_child(uint32_t esp, uint32_t eip, uint32_t argc, ...);
 global create_child
 create_child:
-xchg bx,bx
 mov eax, [esp] ; return address
 lea ecx, [esp+4] ; return stack, minus address
 call save_current_task
@@ -30,6 +29,37 @@ push return_prev_task ; if child returns, return to prev task
 push eax
 ret
 
+; extern void create_user_child(uint32_t esp, uint32_t eip, uint32_t argc, ...);
+global create_user_child
+create_user_child:
+mov eax, [esp] ; return address
+lea ecx, [esp+4] ; return stack, minus address
+call save_current_task
+mov eax, [esp+8] ; new eip
+mov ecx, [esp+12] ; argc
+mov esi, esp ; old esp
+mov esp, [esp+4] ; new esp
+lea esi, [esi+16] ; args
+mov edx, ecx
+neg edx
+lea esp, [esp+edx*4] ; adjust for args
+mov edi, esp
+; copy varargs to new stack
+rep movsd
+push 0x00000000 ; if child returns, return to null, crashing
+mov ecx, 0x20 | 3
+mov ds, cx
+mov es, cx
+mov fs, cx
+mov gs, cx
+mov ecx, esp
+push 0x20 | 3
+push ecx
+pushfd
+push 0x18 | 3
+push eax
+iret
+
 ; return address in EAX
 ; return stack in ECX
 ; we can modify EAX, ECX, EDX
@@ -145,22 +175,22 @@ iret
 ; return address in eax, return stack in ebp
 ;extern save_current_task
 
-extern user_test
-global jmp_usermode_test
-jmp_usermode_test:
-pop eax ; return address
-mov ecx, esp ; return stack
-call save_current_task
-mov esp, 0x800000 ; usermode stack
-mov eax, 0x20 | 3
-mov ds, ax
-mov es, ax
-mov fs, ax
-mov gs, ax
-mov eax, esp
-push 0x20 | 3
-push eax
-pushfd
-push 0x18 | 3
-push user_test
-iret
+;extern user_test
+;global jmp_usermode_test
+;jmp_usermode_test:
+;pop eax ; return address
+;mov ecx, esp ; return stack
+;call save_current_task
+;mov esp, 0x800000 ; usermode stack
+;mov eax, 0x20 | 3
+;mov ds, ax
+;mov es, ax
+;mov fs, ax
+;mov gs, ax
+;mov eax, esp
+;push 0x20 | 3
+;push eax
+;pushfd
+;push 0x18 | 3
+;push user_test
+;iret

testpgrm.nasm

@@ -0,0 +1,36 @@
+[BITS 32]
+[ORG 0x400000]
+xchg bx,bx
+mov edi, 0xB8000
+mov ecx, 80*25
+mov eax, 0x2f00
+rep stosw
+mov edi, 0xB8000
+mov esi, str0
+mov ecx, str0_end - str0
+mov eax, 0x2f00
+.loop:
+lodsb
+stosw
+loop .loop
+mov edi, 0xB8000 + 160 - 2
+.key_loop:
+mov eax, 1 ; command = 01h, get scancode
+int 0x21 ; OS call
+cmp al, 0x3B ; F1
+je .exit
+cmp al, 0x3C ; F2
+je .crash
+cmp ah, 0x00
+je .key_loop
+mov byte [edi], ah ; ASCII value
+add edi, 2
+jmp .key_loop
+.exit:
+mov eax, 0x1337 ; Exit code/Return value
+int 0x30 ; Exit
+.crash:
+jmp 0x00000000
+
+str0: db "Running usermode program from disk! Press F1 to exit. Press F2 to crash."
+str0_end:

tests.c

@@ -1,6 +1,7 @@
 #include "tests.h"
 
-extern char *jmp_usermode_test();
+extern char *user_test();
+extern uint32_t create_user_child(uint32_t esp, uint32_t eip, uint32_t argc, ...);
 
 void TestV86() {
     union V86Regs_t regs;
@@ -21,12 +22,16 @@ void ReloadUser() {
     while (d < &_eusercode)
         *d++ = *s++;
 }
-void TestUser() {
+char TestUser() {
     ReloadUser();
-    char *vga = jmp_usermode_test();
+    char *vga = (char *)(uintptr_t)create_user_child(0x800000, (uintptr_t)user_test, 0);
+    if ((uintptr_t)vga != 0xA0000) {
+        return 1;
+    }
     for (int i = 0; i < 320; i++) {
         vga[i] = i;
     }
+    return 0;
 }
 void TestDiskRead() {
     union V86Regs_t regs;
@@ -119,17 +124,25 @@ void TestFAT() {
 
 void RunTests() {
     uint16_t *vga_text = (uint16_t*)0xb8000;
+    for (int i = 0; i < 80*25; i++)
+        vga_text[i] = 0x1f00;
     uint8_t key;
     vga_text += printStr("V86 Test... ", vga_text);
     //asm ("xchgw %bx, %bx");
     TestV86(); // has int 3 wait in v86
     vga_text = (uint16_t *)0xb8000 + (80*3);
     vga_text += printStr("Done. Press 'N' for next test.", vga_text);
-    while ((key = get_key()) != 'N') {
+    for(;;) {
+        key = get_key();
+        if (key == 'N' || key == 'n') break;
         *vga_text = (*vga_text & 0xFF00) | key;
         vga_text++;
     }
-    TestUser();
+    if (TestUser()) {
+        // Usermode returned wrong value
+        vga_text = nextLine(vga_text);
+        vga_text += printStr("Usermode test failed! Press any key to continue.", vga_text);
+    }
     kbd_wait();
     TestDiskRead();
     kbd_wait();

tests.h

@@ -4,5 +4,6 @@
 #include "interrupt.h"
 #include "v86defs.h"
 #include "kbd.h"
+#include "helper.h"
 
 void RunTests();

usermode.nasm

@@ -6,8 +6,24 @@ mov dword [0xb8004], 0x0f000f00 | 'e' | 'r' << 16
 mov dword [0xb8008], 0x0f000f00 | 'm' | 'o' << 16
 mov dword [0xb800C], 0x0f000f00 | 'd' | 'e' << 16
 mov word [0xb8010], 0x0f00 | '!'
+mov dword [0xb8000+160], 0x0f000f00 | 'F' | 'a' << 16
+mov dword [0xb8004+160], 0x0f000f00 | 'u' | 'l' << 16
+mov dword [0xb8008+160], 0x0f000f00 | 't' | 's' << 16
+mov dword [0xb800C+160], 0x0f000f00 | ':' | ' ' << 16
+mov dword [0xb8000+320], 0x0f000f00 | 'd' | ':' << 16
+mov dword [0xb8004+320], 0x0f000f00 | ' ' | '#' << 16
+mov dword [0xb8008+320], 0x0f000f00 | 'D' | 'I' << 16
+mov dword [0xb800C+320], 0x0f000f00 | 'V' | ' ' << 16
+mov dword [0xb8000+480], 0x0f000f00 | 'p' | ':' << 16
+mov dword [0xb8004+480], 0x0f000f00 | ' ' | 'P' << 16
+mov dword [0xb8008+480], 0x0f000f00 | 'G' | 'F' << 16
+mov dword [0xb800C+480], 0x0f000f00 | 'L' | 'T' << 16
 mov eax, 0 ; command = 00h, get key
 int 0x21 ; OS call
+cmp al, 'd'
+je .div_err
+cmp al, 'p'
+je .page_err
 push 0x00000013 ; eax  AH=0,AL=3 set video mode 3
 push 0x00000000 ; ecx
 push 0x00000000 ; edx
@@ -31,7 +47,9 @@ mov eax, 0xA0000
 ;.dbg:
 ;loop .dbg
 int 0x30 ; Exit
+.page_err:
 mov edx, 0x105000 ; somewhere in kernel mem
 mov edx, [edx] ; should page fault
+.div_err:
 xor ebx, ebx
 div bl ; Unhandled DIV0 exception