Kernel: Support re-mapping MMIOVMObject-backed regions

This is required for example when write combine is enabled on a region after the initial mapping.
Cnidarias · Jun 25, 2024 · 3aa1bd5 · 3aa1bd5
1 parent 8d2a8db
commit 3aa1bd5
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Showing 4 changed files with 13 additions and 1 deletion.
diff --git a/Kernel/Memory/MMIOVMObject.cpp b/Kernel/Memory/MMIOVMObject.cpp
@@ -24,6 +24,7 @@ ErrorOr<NonnullLockRefPtr<MMIOVMObject>> MMIOVMObject::try_create_for_physical_r
 
 MMIOVMObject::MMIOVMObject(PhysicalAddress paddr, FixedArray<RefPtr<PhysicalRAMPage>>&& new_physical_pages)
  : VMObject(move(new_physical_pages))
+ , m_base_address(paddr)
 {
  VERIFY(paddr.page_base() == paddr);
 }

diff --git a/Kernel/Memory/MMIOVMObject.h b/Kernel/Memory/MMIOVMObject.h
@@ -17,10 +17,15 @@ class MMIOVMObject final : public VMObject {
 
  virtual ErrorOr<NonnullLockRefPtr<VMObject>> try_clone() override { return ENOTSUP; }
 
+ PhysicalAddress base_address() const { return m_base_address; }
+
 private:
  MMIOVMObject(PhysicalAddress, FixedArray<RefPtr<PhysicalRAMPage>>&&);
 
  virtual StringView class_name() const override { return "MMIOVMObject"sv; }
+ virtual bool is_mmio() const override { return true; }
+
+ PhysicalAddress m_base_address;
 };
 
 }
diff --git a/Kernel/Memory/Region.cpp b/Kernel/Memory/Region.cpp
@@ -12,6 +12,7 @@
 #include <Kernel/Interrupts/InterruptDisabler.h>
 #include <Kernel/Library/Panic.h>
 #include <Kernel/Memory/AnonymousVMObject.h>
+#include <Kernel/Memory/MMIOVMObject.h>
 #include <Kernel/Memory/MemoryManager.h>
 #include <Kernel/Memory/Region.h>
 #include <Kernel/Memory/SharedInodeVMObject.h>
@@ -355,7 +356,11 @@ ErrorOr<void> Region::map(PageDirectory& page_directory, PhysicalAddress paddr,
 void Region::remap()
 {
  VERIFY(m_page_directory);
- auto result = map(*m_page_directory);
+ ErrorOr<void> result;
+ if (m_vmobject->is_mmio())
+ result = map(*m_page_directory, static_cast<MMIOVMObject const&>(*m_vmobject).base_address());
+ else
+ result = map(*m_page_directory);
  if (result.is_error())
  TODO();
 }

diff --git a/Kernel/Memory/VMObject.h b/Kernel/Memory/VMObject.h
@@ -32,6 +32,7 @@ class VMObject
  virtual bool is_inode() const { return false; }
  virtual bool is_shared_inode() const { return false; }
  virtual bool is_private_inode() const { return false; }
+ virtual bool is_mmio() const { return false; }
 
  size_t page_count() const { return m_physical_pages.size(); }