Kernel: Don't override FramebufferDevice's memory regions on mmap

This additionally refactors FramebufferDevice::try_to_initialize to not
leave the FramebufferDevice in an invalid state on errors.
This also unifies the logic between FramebufferDevice::mmap and
FramebufferDevice::try_to_initialize.
This comes with the drawback of removing the UNMAP_AFTER_INIT attribute
from this function, which wasn't honoured by IntelNativeGraphicsAdapter
anyway.

2 files changed, 22 insertions, 12 deletions

diff --git a/Kernel/Graphics/FramebufferDevice.cpp b/Kernel/Graphics/FramebufferDevice.cpp
index c9b16957a0..e278a3cac0 100644
--- a/Kernel/Graphics/FramebufferDevice.cpp
+++ b/Kernel/Graphics/FramebufferDevice.cpp
@@ -40,11 +40,10 @@ ErrorOr<Memory::Region*> FramebufferDevice::mmap(Process& process, OpenFileDescr
     if (range.size() != framebuffer_length)
         return EOVERFLOW;
 
-    m_userspace_real_framebuffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(m_framebuffer_address, framebuffer_length));
-    m_real_framebuffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(m_framebuffer_address, framebuffer_length));
-    m_swapped_framebuffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_with_size(framebuffer_length, AllocationStrategy::AllocateNow));
-    m_real_framebuffer_region = TRY(MM.allocate_kernel_region_with_vmobject(*m_real_framebuffer_vmobject, framebuffer_length, "Framebuffer", Memory::Region::Access::ReadWrite));
-    m_swapped_framebuffer_region = TRY(MM.allocate_kernel_region_with_vmobject(*m_swapped_framebuffer_vmobject, framebuffer_length, "Framebuffer Swap (Blank)", Memory::Region::Access::ReadWrite));
+    TRY(try_to_initialize());
+
+    if (m_userspace_framebuffer_region)
+        return m_userspace_framebuffer_region;
 
     RefPtr<Memory::VMObject> chosen_vmobject;
     if (m_graphical_writes_enabled) {
@@ -99,16 +98,26 @@ void FramebufferDevice::activate_writes()
     m_graphical_writes_enabled = true;
 }
 
-UNMAP_AFTER_INIT ErrorOr<void> FramebufferDevice::try_to_initialize()
+ErrorOr<void> FramebufferDevice::try_to_initialize()
 {
-    // FIXME: Would be nice to be able to unify this with mmap above, but this
-    //        function is UNMAP_AFTER_INIT for the time being.
+    if (m_initialized)
+        return {};
+
     auto framebuffer_length = TRY(buffer_length(0));
     framebuffer_length = TRY(Memory::page_round_up(framebuffer_length));
-    m_real_framebuffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(m_framebuffer_address, framebuffer_length));
-    m_swapped_framebuffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_with_size(framebuffer_length, AllocationStrategy::AllocateNow));
-    m_real_framebuffer_region = TRY(MM.allocate_kernel_region_with_vmobject(*m_real_framebuffer_vmobject, framebuffer_length, "Framebuffer", Memory::Region::Access::ReadWrite));
-    m_swapped_framebuffer_region = TRY(MM.allocate_kernel_region_with_vmobject(*m_swapped_framebuffer_vmobject, framebuffer_length, "Framebuffer Swap (Blank)", Memory::Region::Access::ReadWrite));
+
+    auto real_framebuffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(m_framebuffer_address, framebuffer_length));
+    auto swapped_framebuffer_vmobject = TRY(Memory::AnonymousVMObject::try_create_with_size(framebuffer_length, AllocationStrategy::AllocateNow));
+    auto real_framebuffer_region = TRY(MM.allocate_kernel_region_with_vmobject(*real_framebuffer_vmobject, framebuffer_length, "Framebuffer", Memory::Region::Access::ReadWrite));
+    auto swapped_framebuffer_region = TRY(MM.allocate_kernel_region_with_vmobject(*swapped_framebuffer_vmobject, framebuffer_length, "Framebuffer Swap (Blank)", Memory::Region::Access::ReadWrite));
+
+    m_real_framebuffer_vmobject = move(real_framebuffer_vmobject);
+    m_swapped_framebuffer_vmobject = move(swapped_framebuffer_vmobject);
+    m_real_framebuffer_region = move(real_framebuffer_region);
+    m_swapped_framebuffer_region = move(swapped_framebuffer_region);
+
+    m_initialized = true;
+
     return {};
 }
 
diff --git a/Kernel/Graphics/FramebufferDevice.h b/Kernel/Graphics/FramebufferDevice.h
index 207155db76..7387d200bd 100644
--- a/Kernel/Graphics/FramebufferDevice.h
+++ b/Kernel/Graphics/FramebufferDevice.h
@@ -67,6 +67,7 @@ private:
 
     bool m_graphical_writes_enabled { true };
     bool m_write_combine { true };
+    bool m_initialized { false };
 
     RefPtr<Memory::AnonymousVMObject> m_userspace_real_framebuffer_vmobject;
     Memory::Region* m_userspace_framebuffer_region { nullptr };