From 1afe255fed75a83783482756e51e951a8557a82f Mon Sep 17 00:00:00 2001
From: Alex <enderice2@users.noreply.github.com>
Date: Sun, 20 Nov 2022 16:13:49 +0200
Subject: [PATCH] Hope now scheduler won't crash at IPC Service

---
 .../amd64/SystemCallsAssemblyStub.asm         | 48 ++++++++++---------
 Tasking/InterProcessCommunication.cpp         |  5 +-
 2 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/Architecture/amd64/SystemCallsAssemblyStub.asm b/Architecture/amd64/SystemCallsAssemblyStub.asm
index 25e281f1..1944ef13 100644
--- a/Architecture/amd64/SystemCallsAssemblyStub.asm
+++ b/Architecture/amd64/SystemCallsAssemblyStub.asm
@@ -1,19 +1,6 @@
 [BITS 64]
-ALIGN	4096
-extern SystemCallsHandler
-global SystemCallHandlerStub
-SystemCallHandlerStub:
-    swapgs
-    mov [gs:0x8], rsp   ; CPUData->TempStack
-    mov rsp, [gs:0x0]   ; CPUData->SystemCallStack
 
-    push qword 0x1b     ; user data segment
-    push qword [gs:0x8] ; saved stack
-    push r11            ; saved rflags
-    push qword 0x23     ; user code segment
-    push rcx            ; Current RIP
-
-    cld
+%macro PushAllSC 0
     push rax
     push rbx
     push rcx
@@ -29,11 +16,9 @@ SystemCallHandlerStub:
     push r13
     push r14
     push r15
+%endmacro
 
-    mov rdi, rsp
-    mov rbp, 0
-    call SystemCallsHandler
-
+%macro PopAllSC 0
     pop r15
     pop r14
     pop r13
@@ -48,8 +33,27 @@ SystemCallHandlerStub:
     pop rdx
     pop rcx
     pop rbx
+%endmacro
 
-    mov rsp, [gs:0x8]
-    swapgs
-    sti
-    o64 sysret
+ALIGN 4096
+extern SystemCallsHandler
+global SystemCallHandlerStub
+SystemCallHandlerStub:
+    swapgs                  ; Swap gs and kernelgs
+    mov [gs:0x8], rsp       ; CPUData->TempStack
+    mov rsp, [gs:0x0]       ; CPUData->SystemCallStack
+    push qword 0x1b         ; User data segment
+    push qword [gs:0x8]     ; Saved stack
+    push r11                ; Saved rflags
+    push qword 0x23         ; User code segment
+    push rcx                ; Current instruction pointer
+    cld                     ; Clear direction flag
+    PushAllSC               ; Push all registers
+    mov rdi, rsp            ; Pass pointer to registers
+    mov rbp, 0              ; Pass 0 as return address
+    call SystemCallsHandler ; Call system call handler
+    PopAllSC                ; Pop all registers except rax
+    mov rsp, [gs:0x8]       ; Restore stack
+    swapgs                  ; Swap back gs and kernelgs
+    sti                     ; Enable interrupts
+    o64 sysret              ; Return to user mode
diff --git a/Tasking/InterProcessCommunication.cpp b/Tasking/InterProcessCommunication.cpp
index 4a94acd2..46e69880 100644
--- a/Tasking/InterProcessCommunication.cpp
+++ b/Tasking/InterProcessCommunication.cpp
@@ -131,7 +131,10 @@ namespace InterProcessCommunication
         trace("IPC Service Started.");
         TaskManager->GetCurrentThread()->SetPriority(1);
         // TODO: do something useful here, like, IPC event viewer or smth...
-        CPU::Pause(true);
+        while (1)
+        {
+            // The scheduler doesn't like CPU::Pause for some reason. :/
+        }
     }
 
     IPC::IPC()