From b2ebf6c7985534968b3238e06e0e43a70b2bebb8 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sat, 20 Apr 2019 19:23:45 +0200
Subject: [PATCH] Kernel: Shrink Thread by making kernel resume TSS
 heap-allocated.

---
 Kernel/Process.cpp | 3 ++-
 Kernel/Thread.cpp  | 4 ++--
 Kernel/Thread.h    | 3 ++-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 2a841a1089..4a130e3420 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -694,7 +694,8 @@ void Process::sys$sigreturn()
 {
     InterruptDisabler disabler;
     Scheduler::prepare_to_modify_tss(*current);
-    current->m_tss = current->m_tss_to_resume_kernel;
+    current->m_tss = *current->m_tss_to_resume_kernel;
+    current->m_tss_to_resume_kernel.clear();
 #ifdef SIGNAL_DEBUG
     kprintf("sys$sigreturn in %s(%u)\n", name().characters(), pid());
     auto& tss = current->tss();
diff --git a/Kernel/Thread.cpp b/Kernel/Thread.cpp
index ebd43a23b4..87295fc6b9 100644
--- a/Kernel/Thread.cpp
+++ b/Kernel/Thread.cpp
@@ -347,9 +347,9 @@ ShouldUnblockThread Thread::dispatch_signal(byte signal)
         kprintf("dispatch_signal to %s(%u) in state=%s with return to %w:%x\n", name().characters(), pid(), to_string(state()), ret_cs, ret_eip);
 #endif
         ASSERT(is_blocked());
-        m_tss_to_resume_kernel = m_tss;
+        m_tss_to_resume_kernel = make<TSS32>(m_tss);
 #ifdef SIGNAL_DEBUG
-        kprintf("resume tss pc: %w:%x stack: %w:%x flags: %x cr3: %x\n", m_tss_to_resume_kernel.cs, m_tss_to_resume_kernel.eip, m_tss_to_resume_kernel.ss, m_tss_to_resume_kernel.esp, m_tss_to_resume_kernel.eflags, m_tss_to_resume_kernel.cr3);
+        kprintf("resume tss pc: %w:%x stack: %w:%x flags: %x cr3: %x\n", m_tss_to_resume_kernel.cs, m_tss_to_resume_kernel->eip, m_tss_to_resume_kernel->ss, m_tss_to_resume_kernel->esp, m_tss_to_resume_kernel->eflags, m_tss_to_resume_kernel->cr3);
 #endif
 
         if (!m_signal_stack_user_region) {
diff --git a/Kernel/Thread.h b/Kernel/Thread.h
index 1a898dd82f..c0609daea0 100644
--- a/Kernel/Thread.h
+++ b/Kernel/Thread.h
@@ -6,6 +6,7 @@
 #include <Kernel/UnixTypes.h>
 #include <AK/AKString.h>
 #include <AK/InlineLinkedList.h>
+#include <AK/OwnPtr.h>
 #include <AK/RetainPtr.h>
 #include <AK/Vector.h>
 
@@ -138,7 +139,7 @@ private:
     Process& m_process;
     int m_tid { -1 };
     TSS32 m_tss;
-    TSS32 m_tss_to_resume_kernel;
+    OwnPtr<TSS32> m_tss_to_resume_kernel;
     FarPtr m_far_ptr;
     dword m_ticks { 0 };
     dword m_ticks_left { 0 };