kernel: Move "push_mem_on_stack" and "pop_mem_from_stack" to MemoryManager

kernel/src/arch/x86_64/Thread.cpp

@@ -71,31 +71,14 @@ void switch_context(Thread* old_thread, Thread* new_thread, Registers* regs)
     memcpy(regs, &new_thread->regs, sizeof(Registers));
 }
 
-// FIXME: Move this function to a common location (also used in ThreadImage)
 Result<u64> Thread::push_mem_on_stack(const u8* mem, usize size)
 {
-    if ((regs.rsp - size) < stack.bottom()) return err(E2BIG);
-
-    if (!MemoryManager::validate_user_write((void*)(regs.rsp - size), size)) return err(EFAULT);
-
-    regs.rsp -= size;
-
-    memcpy((void*)regs.rsp, mem, size);
-
-    return regs.rsp;
+    return MemoryManager::push_mem_on_stack(mem, size, stack, regs.rsp);
 }
 
 Result<u64> Thread::pop_mem_from_stack(u8* mem, usize size)
 {
-    if ((regs.rsp + size) > stack.top()) return err(E2BIG);
-
-    if (!MemoryManager::validate_user_read((void*)regs.rsp, size)) return err(EFAULT);
-
-    memcpy(mem, (void*)regs.rsp, size);
-
-    regs.rsp += size;
-
-    return regs.rsp;
+    return MemoryManager::pop_mem_from_stack(mem, size, stack, regs.rsp);
 }
 
 bool Thread::deliver_signal(int signo, Registers* current_regs)

kernel/src/arch/x86_64/disk/ATA.h

@@ -3,6 +3,7 @@
 #include "fs/devices/BlockDevice.h"
 #include "fs/devices/DeviceRegistry.h"
 #include "lib/Mutex.h"
+#include "thread/Thread.h"
 #include <luna/Atomic.h>
 #include <luna/SharedPtr.h>
 #include <luna/StaticString.h>

kernel/src/lib/Mutex.h

@@ -1,7 +1,9 @@
 #pragma once
-#include "thread/Thread.h"
 #include <luna/CircularQueue.h>
 #include <luna/Spinlock.h>
+#include <sys/types.h>
+
+class Thread;
 
 class Mutex
 {

kernel/src/memory/MemoryManager.cpp

@@ -641,4 +641,30 @@ namespace MemoryManager
     {
         return free_mem + used_mem + reserved_mem;
     }
+
+    Result<u64> push_mem_on_stack(const u8* mem, usize size, const Stack& stack, u64& sp)
+    {
+        if ((sp - size) < stack.bottom()) return err(E2BIG);
+
+        if (!MemoryManager::validate_user_write((void*)(sp - size), size)) return err(EFAULT);
+
+        sp -= size;
+
+        memcpy((void*)sp, mem, size);
+
+        return sp;
+    }
+
+    Result<u64> pop_mem_from_stack(u8* mem, usize size, const Stack& stack, u64& sp)
+    {
+        if ((sp + size) > stack.top()) return err(E2BIG);
+
+        if (!MemoryManager::validate_user_read((void*)sp, size)) return err(EFAULT);
+
+        memcpy(mem, (void*)sp, size);
+
+        sp += size;
+
+        return sp;
+    }
 }

kernel/src/memory/MemoryManager.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "arch/MMU.h"
 #include <luna/Result.h>
+#include <luna/Stack.h>
 #include <luna/String.h>
 #include <luna/Types.h>
 
@@ -88,4 +89,7 @@ namespace MemoryManager
     usize used();
     usize reserved();
     usize total();
+
+    Result<u64> push_mem_on_stack(const u8* mem, usize size, const Stack& stack, u64& sp);
+    Result<u64> pop_mem_from_stack(u8* mem, usize size, const Stack& stack, u64& sp);
 }

kernel/src/sys/setitimer.cpp

@@ -118,7 +118,6 @@ Result<u64> sys_timer_create(Registers*, SyscallArgs args)
     if (ksevp.sigev_signo <= 0 || ksevp.sigev_signo > NSIG) return err(EINVAL);
 
     int id = TRY(current->allocate_timerid());
-    current->posix_timers[id] = Timer {};
 
     Timer* timer = current->posix_timers[id].value_ptr();
     timer->signo = ksevp.sigev_signo;

kernel/src/thread/Thread.cpp

@@ -61,10 +61,15 @@ Result<FileDescriptor*> Thread::resolve_fd(int fd)
 
 Result<int> Thread::allocate_timerid()
 {
+    ScopedMutexLock lock(posix_timer_mutex);
+
     for (int i = 0; i < MAX_POSIX_TIMERS; i++)
     {
-        // FIXME: Possible race condition, this should be used alongside a mutex.
-        if (!posix_timers[i].has_value()) { return i; }
+        if (!posix_timers[i].has_value())
+        {
+            posix_timers[i] = Timer {};
+            return i;
+        }
     }
 
     return err(EMFILE);

kernel/src/thread/Thread.h

@@ -3,6 +3,7 @@
 #include "arch/MMU.h"
 #include "fs/OpenFileDescription.h"
 #include "fs/VFS.h"
+#include "lib/Mutex.h"
 #include "memory/AddressSpace.h"
 #include <bits/signal.h>
 #include <luna/Bitset.h>
@@ -109,6 +110,7 @@ struct Thread : public LinkedListNode<Thread>
     Clock profiling_clock;
 
     Option<Timer> posix_timers[MAX_POSIX_TIMERS];
+    Mutex posix_timer_mutex;
 
     Result<int> allocate_timerid();
     Result<Timer*> resolve_timerid(int id);

kernel/src/thread/ThreadImage.cpp

@@ -67,15 +67,7 @@ Result<OwnedPtr<ThreadImage>> ThreadImage::clone_from_thread(Thread* parent)
 
 Result<u64> ThreadImage::push_mem_on_stack(const u8* mem, usize size)
 {
-    if ((m_sp - size) < m_user_stack.bottom()) return err(E2BIG);
-
-    if (!MemoryManager::validate_user_write((void*)(m_sp - size), size)) return err(EFAULT);
-
-    m_sp -= size;
-
-    memcpy((void*)m_sp, mem, size);
-
-    return m_sp;
+    return MemoryManager::push_mem_on_stack(mem, size, m_user_stack, m_sp);
 }
 
 Result<u64> ThreadImage::push_string_vector_on_stack(const Vector<String>& vec)