WIP: GDT is now right. Have to debug iretq GPF

include/asm.h

@@ -70,11 +70,6 @@ extern void KeSendEOItoPIC(uchar isr);
 extern void KeEnableNMI(void);
 extern void KeDisableNMI(void);
 
-//
-// System Call
-//
-extern error_t KeSyscall(ulong code);
-
 //
 // Restore IRQ flag to its state before KePauseIRQs
 //

include/kernel/ke/syscall.h

@@ -31,6 +31,8 @@
 
 //----------------------------------------------------------------------------//
 
+extern error_t KeSyscall(ulong code);
+
 extern void KeJumpToUserspace(ulong args, void *entryPoint, void *stackAddr);
 
 error_t _KeSyscallHandler(ulong code);

kaleid/kernel/ke/cpuf.asm

@@ -26,7 +26,6 @@
 
 global divideByZero
 global KeActivateSSE
-global KeSyscall
 
 %include "kaleid/kernel/ke/cpuf.inc"
 
@@ -50,10 +49,3 @@ KeActivateSSE:
     mov cr4, rax
     pop rax
     ret
-
-;; 
-;;
-;;
-KeSyscall:
-    int 0x80
-    ret

kaleid/kernel/ke/syscall.asm

@@ -27,24 +27,35 @@
 %include "kaleid/kernel/ke/cpuf.inc"
 
 global KeJumpToUserspace
+global KeSyscall
+extern KernLog
 
+;;
+;; To get ring3 code running
+;;
 KeJumpToUserspace:
 
     ; rdi = user args
     ; rsi = entry point in user space
     ; rdx = user space stack
 
-    mov rax, 0x10 ; Selector 0x10 (User Data) + RPL 3
+    mov rax, 0x18 ; Selector 0x18 (User Data) + RPL 3
-    mov ds, ax
+    mov ds, rax
-    mov es, ax
+    mov es, rax
 
 ; Build a fake iret frame
-    push rax          ; Selector 0x10 (User Data) + RPL 3
+    push rax          ; Selector 0x18 (User Data) + RPL 3
     push rdx          ; User space stack
-    push 0x202        ; rflags = interrupt enable + reserved bit
+    push QWORD 0x202  ; rflags = interrupt enable + reserved bit
-    push 0x10         ; Selector 0x10 (User Code) + RPL 3
+    push QWORD 0x20   ; Selector 0x20 (User Code) + RPL 3
     push rsi          ; Entry point in user space
     
-    xor rax, rax
-
     iretq
+
+
+;; 
+;; Syscall trigger
+;;
+KeSyscall:
+    int 0x80
+    ret

kaleid/kernel/mm/gdt.c

@@ -27,13 +27,13 @@
 #include <init/boot.h>
 
 GdtPtr_t gdtPtr;
-GdtEntry_t gdt[5] __attribute__((__aligned__(KPAGESIZE)));
+GdtEntry_t gdt[7] __attribute__((__aligned__(KPAGESIZE)));
 TssDescriptor_t tssDesc __attribute__((__aligned__(KPAGESIZE)));
 Tss_t tss __attribute__((__aligned__(KPAGESIZE)));
 
 void MmInitGdt(void)
 {
-    ushort tssOffset = (ushort)((ulong)(&gdt[3]) - (ulong)(&gdt[0]));
+    ushort tssOffset = (ushort)((ulong)(&gdt[5]) - (ulong)(&gdt[0]));
 
     gdtPtr.base = (ulong)&gdt[0];
     gdtPtr.limit = sizeof(gdt) - 1;
@@ -43,14 +43,24 @@ void MmInitGdt(void)
     memzero((void *)&tss, sizeof(tss));
     
     // Kernel codeseg
-    gdt[1].lowLimit     = 0xFFFF;
+    gdt[1].lowLimit     = 0x0;
-    gdt[1].access       = 0x98;
+    gdt[1].access       = 0x9A;
     gdt[1].flags        = 0x20;
     
+    // Kernel dataseg
+    gdt[2].lowLimit     = 0x0;
+    gdt[2].access       = 0x92;
+    gdt[2].flags        = 0x00;
+    
+    // User dataseg
+    gdt[3].lowLimit     = 0x0;
+    gdt[3].access       = 0xF2;
+    gdt[3].flags        = 0x20;
+    
     // User codeseg
-    gdt[2].lowLimit     = 0xFFFF;
+    gdt[4].lowLimit     = 0x0;
-    gdt[2].access       = 0xF8;
+    gdt[4].access       = 0xFA;
-    gdt[2].flags        = 0x20;
+    gdt[4].flags        = 0x20;
 
     tssDesc.access          = 0x89;
     tssDesc.flags           = 0x40;
@@ -66,22 +76,19 @@ void MmInitGdt(void)
     tss.rsp0 = (ulong)memalign(4*MB, 4*KB) + 4*MB;  // Another Stack
     tss.iomap_base = sizeof(tss);
 
-    DebugLog("ISR Stacks initialized : Rescue %p, Normal %p, %p\n",
+    memmove(&gdt[5], &tssDesc, sizeof(TssDescriptor_t));
-            tss.ist1,
-            tss.ist2,
-            tss.ist3);
-
-    memmove(&gdt[3], &tssDesc, sizeof(TssDescriptor_t));
 
     DebugLog("GDT & TSS initialized\n");
-    DebugLog("gdt[0] : %#b\n", gdt[0]);
+    DebugLog("Null descriptor        : %#p\n", &gdt[0]);
-    DebugLog("gdt[1] : %#b\n", gdt[1]);
+    DebugLog("Kernel code descriptor : %#p\n", &gdt[1]);
-    DebugLog("gdt[2] : %#b\n", gdt[2]);
+    DebugLog("Kernel data descriptor : %#p\n", &gdt[2]);
-    DebugLog("tss    : %#b\n", gdt[3]);
+    DebugLog("User data descriptor   : %#p\n", &gdt[3]);
-    DebugLog("ist1   : %#p\n", tss.ist1);
+    DebugLog("User code descriptor   : %#p\n", &gdt[4]);
-    DebugLog("ist2   : %#p\n", tss.ist2);
+    DebugLog("tss  : %#p\n", &gdt[5]);
-    DebugLog("ist3   : %#p\n", tss.ist3);
+    DebugLog("ist1 : %#p\n", tss.ist1);
-    DebugLog("rsp0   : %#p\n", tss.ist1);
+    DebugLog("ist2 : %#p\n", tss.ist2);
+    DebugLog("ist3 : %#p\n", tss.ist3);
+    DebugLog("rsp0 : %#p\n", tss.ist1);
 
     MmLoadGdt(&gdtPtr, tssOffset);
 }

kaleid/kernel/sh/testcmds.c

@@ -331,8 +331,8 @@ error_t CmdSyscallTest(int argc, char **argv, char *cmdline)
 
 error_t CmdRing3Test(int argc, char **argv, char *cmdline)
 {
-    size_t size = 50*MB;
+    size_t size = 1*KB;
-    void *entryPoint = (void*)USERSPACE + 51*KB;
+    void *entryPoint = (void*)USERSPACE;
     ulong flags = PRESENT | READWRITE | USERMODE;
 
     KernLog("Allocating %u o...\n", size);
@@ -348,8 +348,8 @@ error_t CmdRing3Test(int argc, char **argv, char *cmdline)
         return ENOMEM;
     }
     
-    size = 50*KB;
+    size = 1*KB;
-    void *stackAddr = (void*)USERSPACE;
+    void *stackAddr = (void*)USERSPACE + 4*KPAGESIZE;
     flags = PRESENT | READWRITE | USERMODE;
 
     KernLog("Allocating %u o...\n", size);
@@ -365,6 +365,14 @@ error_t CmdRing3Test(int argc, char **argv, char *cmdline)
         return ENOMEM;
     }
     
+    KernLog("Entrypoint : %p, stack address : %p\n", entryPoint, stackAddr);
+    
+    uchar *code = (uchar*)entryPoint;
+    
+/*    *code = 0x90;       // nop*/
+/*    *(code+1) = 0xEB;   // jmp*/
+/*    *(code+2) = 0xFD;   //      short 0x0*/
+
     KeJumpToUserspace(0, entryPoint, stackAddr);
 
     return EOK;