Add NO_MMAP flag in the compilation scripts

CMakeLists.txt

@@ -186,6 +186,7 @@ option(USE_SYSTEM_MINIUPNPC "Dynamically link against system miniUPnPc" ${USE_SY
 option(USE_ASAN "Use address sanitizer" OFF)
 option(USE_UBSAN "Use undefined behaviour sanitizer" OFF)
 option(USE_CCACHE "Use ccache if detected" ON)
+option(USE_NO_MMAP "Disable mmap usage" OFF)
 
 if(USE_CCACHE)
 	include(ccache)
@@ -247,6 +248,12 @@ if(HTTPS_NOT_AVAILABLE)
 	add_definitions(-DHTTPS_NOT_AVAILABLE)
 endif()
 
+# Disable the usage of MMAP for the memory system.
+# It is not tested on all platforms and can cause issues.
+if(USE_NO_MMAP)
+	add_definitions(-DNO_MMAP -DMASKED_PSP_MEMORY)
+endif()
+
 # Work around for some misfeature of the current glslang build system
 include_directories(ext/glslang)
 

Common/MemArenaPosix.cpp

@@ -137,7 +137,7 @@ void MemArena::ReleaseView(s64 offset, void* view, size_t size) {
 
 u8* MemArena::Find4GBBase() {
 	// Now, create views in high memory where there's plenty of space.
-#if PPSSPP_ARCH(64BIT) && !defined(USE_ASAN)
+#if PPSSPP_ARCH(64BIT) && !defined(USE_ASAN) && !defined(NO_MMAP)
 	// We should probably just go look in /proc/self/maps for some free space.
 	// But let's try the anonymous mmap trick, just like on 32-bit, but bigger and
 	// aligned to 4GB for the movk trick. We can ensure that we get an aligned 4GB

b.sh

@@ -81,6 +81,9 @@ do
 		--alderlake) echo "Alderlake opt"
 			CMAKE_ARGS="-DCMAKE_C_FLAGS=\"-march=alderlake\" -DCMAKE_CPP_FLAGS=\"-march=alderlake\""
 			;;
+		--no_mmap) echo "Disable mmap"
+			CMAKE_ARGS="-DUSE_NO_MMAP=ON ${CMAKE_ARGS}"
+			;;
 		*) MAKE_OPT="$1 ${MAKE_OPT}"
 			;;
 	esac