Userspace can trigger syscalls

Makefile

@@ -344,7 +344,7 @@ run: test
 
 testnokvm: all installonimage
 	@qemu-system-x86_64 -vga std -machine type=q35 \
-	 -cpu host -rtc base=localtime -m $(ram) \
+	 -cpu qemu64 -rtc base=localtime -m $(ram) \
 	 -drive file=$(installdisk),index=0,media=disk,format=raw \
 	 -net nic,model=rtl8139 -audiodev id=pa,driver=pa \
 	 -machine pcspk-audiodev=pa \
@@ -359,7 +359,7 @@ testnosnd: all installonimage
 
 test32: all installonimage
 	@qemu-system-i386 -vga std -enable-kvm -machine type=q35 \
-	 -cpu host -rtc base=localtime -m $(ram) \
+	 -cpu qemu32 -rtc base=localtime -m $(ram) \
 	 -drive file=$(installdisk),index=0,media=disk,format=raw \
 	 -net nic,model=rtl8139 -audiodev id=pa,driver=pa \
 	 -machine pcspk-audiodev=pa \
@@ -390,7 +390,7 @@ ddd: all installonimage
 
 gdbnokvm: all installonimage
 	@setsid qemu-system-x86_64 -vga std -machine type=q35 \
-	 -cpu host -rtc base=localtime -m $(ram) \
+	 -cpu qemu64 -rtc base=localtime -m $(ram) \
 	 -drive file=$(installdisk),index=0,media=disk,format=raw \
 	 -net nic,model=rtl8139 -audiodev id=pa,driver=pa \
 	 -machine pcspk-audiodev=pa -no-reboot -no-shutdown\
@@ -403,7 +403,7 @@ gdbnokvm: all installonimage
 
 dddnokvm: all installonimage
 	@setsid qemu-system-x86_64 -vga std -machine type=q35 \
-	 -cpu host -rtc base=localtime -m $(ram) \
+	 -cpu qemu64 -rtc base=localtime -m $(ram) \
 	 -drive file=$(installdisk),index=0,media=disk,format=raw \
 	 -net nic,model=rtl8139 -audiodev id=pa,driver=pa \
 	 -machine pcspk-audiodev=pa -no-reboot -no-shutdown\

include/kernel/ke/syscall.h

@@ -35,7 +35,7 @@ extern error_t KeSyscall(ulong code);
 
 extern void KeJumpToUserspace(ulong args, void *entryPoint, void *stackAddr);
 
-error_t _KeSyscallHandler(ulong code);
+error_t _KeSyscallHandler(ulong code, ISRFrame_t *regs);
 
 //----------------------------------------------------------------------------//
 

kaleid/kernel/ke/idt.c

@@ -122,12 +122,24 @@ void KeSetupIDT(void)
     // Set IDT ptr
     _KeIdtPtr.limit = (sizeof(IdtEntry_t) * 256) - 1;
     _KeIdtPtr.base = &idt;
+    
+    /* ISR flags : 
+        0x8E = 1 0 0 0 1 1 1 0
+               | | | | '-'-'-'------ Gate type : 0xE is interrupt gate
+               | | | '-------------- S (must be 0)
+               | '-'---------------- DPL : 0 is Supervisor
+               '-------------------- P : 1 is present
+        0xEE = 1 1 1 0 1 1 1 0
+               | | | | '-'-'-'------ Gate type : 0xE is interrupt gate
+               | | | '-------------- S (must be 0)
+               | '-'---------------- DPL : 3 is user
+               '-------------------- P : 1 is present */
 
     // Set IDT Exception Gates
     KeSetIDTGate(0x00, (ulong)isr0, codeSeg, 0x8E, 2);
     KeSetIDTGate(0x01, (ulong)isr1, codeSeg, 0x8E, 2);
     KeSetIDTGate(0x02, (ulong)isr2, codeSeg, 0x8E, 2);
-    KeSetIDTGate(0x03, (ulong)isr3, codeSeg, 0x8E, 2);
+    KeSetIDTGate(0x03, (ulong)isr3, codeSeg, 0xEE, 2);
     KeSetIDTGate(0x04, (ulong)isr4, codeSeg, 0x8E, 2);
     KeSetIDTGate(0x05, (ulong)isr5, codeSeg, 0x8E, 2);
     KeSetIDTGate(0x06, (ulong)isr6, codeSeg, 0x8E, 2);
@@ -176,7 +188,7 @@ void KeSetupIDT(void)
     KeSetIDTGate(0x2F, (ulong)isr47, codeSeg, 0x8E, 3);
     
     // SYSCALL
-    KeSetIDTGate(0x80, (ulong)isr128, codeSeg, 0x8E, 3); // Directly handled by _KeSyscallHandler, without registration
+    KeSetIDTGate(0x80, (ulong)isr128, codeSeg, 0xEE, 3); // Directly handled by _KeSyscallHandler, without registration
 
     KeIdtIsInitialized++;
 
@@ -328,7 +340,7 @@ void _KeHandleISR(ISRFrame_t *regs)
     if (regs->intNo >= 0x20 && regs->intNo <= 0x2F && !(KeGetIrqRegister(0x0b) & (1<<(regs->intNo - 0x20)))) {
        KeSpuriousCount++;
        return;
-   }
+    }
 
     for (int i = 0; i < isrList.n; i++) {
         if (regs->intNo == isrList.entry[i].isrNo) {

kaleid/kernel/ke/isr.asm

@@ -82,7 +82,21 @@ Die:
 ;; System call pre-handler
 ;;
 syscallPreHandler:
-    pushAll
+    push r15
+    push r14
+    push r13
+    push r12
+    push r11
+    push r10
+    push r9
+    push r8
+    push rbp
+    push 0
+    push rsi
+    push rdx
+    push rcx
+    push rbx
+    push rax
     mov rax, cr8
     push rax
     mov rax, cr4
@@ -99,17 +113,33 @@ syscallPreHandler:
 
     ; Call the C routine to dispatch interrupts
     cld             ; DF must be cleared by the caller
-    mov rdi, rsp    ; First argument points to the processor state
+    mov rsi, rsp    ; First argument points to the processor state
     mov rbp, 0      ; Terminate stack traces here
 
     call _KeSyscallHandler
 
     ; pop the control registers
     add rsp, 48
-    ; pop registers
-    popAll
+    ; pop registers except return value
+    pop rbx
+    pop rbx ; 2x rbx to discard rax
+    pop rcx
+    pop rdx
+    pop rsi
+    pop rdi
+    pop rbp
+    pop r8
+    pop r9
+    pop r10
+    pop r11
+    pop r12
+    pop r13
+    pop r14
+    pop r15
     ; pop the error code and interrupt id
     add rsp, 16
+    
+    iretq
 
 Die2:
     hlt

kaleid/kernel/ke/syscall.c

@@ -27,9 +27,14 @@
 #include <ke/idt.h>
 #include <io/vga.h>
 
-error_t _KeSyscallHandler(ulong code)
+error_t _KeSyscallHandler(ulong code, ISRFrame_t *regs)
 {
-    DebugLog("Got a system call code %ld !\n", code);
+    DebugLog("Got a system call code %ld from cs %#x\n", code, regs->cs);
+    
+    if ((ulong)regs->cs != (ulong)BtLoaderInfo.codeSegment) {
+        bprintf(BStdOut, "Got a system call from userspace code %d\n", code);
+        BStdOut->flusher(BStdOut);
+    }
     
     return EOK;
 }

kaleid/user/test/test.asm

@@ -28,8 +28,8 @@ global UserTest
 global EndOfUser
 
 UserTest:
-    mov rdi, 13
-    ;int 0x80
+    mov rdi, 45
+    int 0x80
 
 .clone:
     nop