Core: Don't create page table mappings before R/C bits are set

This gets rid of the hack of setting the R and C bits pessimistically,
reversing the performance regression in Rogue Squadron 3.

1 files changed, 18 insertions, 2 deletions

diff --git a/Source/Core/Common/MemArenaAndroid.cpp b/Source/Core/Common/MemArenaAndroid.cpp
index 1db5afb91d..81c27b7677 100644
--- a/Source/Core/Common/MemArenaAndroid.cpp
+++ b/Source/Core/Common/MemArenaAndroid.cpp
@@ -123,9 +123,13 @@ void MemArena::ReleaseMemoryRegion()
   }
 }
 
-void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base)
+void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base, bool writeable)
 {
-  void* retval = mmap(base, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, m_shm_fd, offset);
+  int prot = PROT_READ;
+  if (writeable)
+    prot |= PROT_WRITE;
+
+  void* retval = mmap(base, size, prot, MAP_SHARED | MAP_FIXED, m_shm_fd, offset);
   if (retval == MAP_FAILED)
   {
     NOTICE_LOG_FMT(MEMMAP, "mmap failed");
@@ -137,6 +141,18 @@ void* MemArena::MapInMemoryRegion(s64 offset, size_t size, void* base)
   }
 }
 
+bool MemArena::ChangeMappingProtection(void* view, size_t size, bool writeable)
+{
+  int prot = PROT_READ;
+  if (writeable)
+    prot |= PROT_WRITE;
+
+  int retval = mprotect(view, size, prot);
+  if (retval != 0)
+    NOTICE_LOG_FMT(MEMMAP, "mprotect failed");
+  return retval == 0;
+}
+
 void MemArena::UnmapFromMemoryRegion(void* view, size_t size)
 {
   void* retval = mmap(view, size, PROT_NONE, MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1, 0);