From 187b4bb7d35c2263e0081ef20382397360bf7611 Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Sun, 31 Jul 2016 17:14:39 -0700
Subject: [PATCH] POSIX: Use a fixed base for executable memory

---
 CMakeLists.txt                     |  2 +-
 src/arm/dynarec-arm/dynarec-impl.c |  2 +-
 src/platform/posix/exec-mem.s      |  4 ++++
 src/platform/posix/memory.c        | 11 ++++++++++-
 4 files changed, 16 insertions(+), 3 deletions(-)
 create mode 100644 src/platform/posix/exec-mem.s

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3bf33af19..42e83fe76 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -160,7 +160,7 @@ elseif(UNIX)
 	endif()
 
 	list(APPEND CORE_VFS_SRC ${CMAKE_CURRENT_SOURCE_DIR}/src/util/vfs/vfs-fd.c ${CMAKE_CURRENT_SOURCE_DIR}/src/util/vfs/vfs-dirent.c)
-	file(GLOB OS_SRC ${CMAKE_CURRENT_SOURCE_DIR}/src/platform/posix/*.c)
+	file(GLOB OS_SRC ${CMAKE_CURRENT_SOURCE_DIR}/src/platform/posix/*.[cs])
 	source_group("POSIX-specific code" FILES ${OS_SRC})
 endif()
 
diff --git a/src/arm/dynarec-arm/dynarec-impl.c b/src/arm/dynarec-arm/dynarec-impl.c
index b47b7b242..b7dabbe8a 100644
--- a/src/arm/dynarec-arm/dynarec-impl.c
+++ b/src/arm/dynarec-arm/dynarec-impl.c
@@ -129,7 +129,7 @@ void ARMDynarecRecompileTrace(struct ARMCore* cpu, struct ARMDynarecTrace* trace
 		EMIT(&ctx, PUSH, AL, 0x4030);
 		EMIT(&ctx, MOV, AL, 4, 0);
 		EMIT(&ctx, LDRI, AL, 5, 0, ARM_PC * sizeof(uint32_t));
-		struct ARMInstructionInfo info;
+		__attribute__((aligned(64))) struct ARMInstructionInfo info;
 		while (true) {
 			uint16_t instruction = cpu->memory.load16(cpu, ctx.address, 0);
 			struct ARMDynarecLabel* label = &ctx.labels[(ctx.address - trace->start) >> 1];
diff --git a/src/platform/posix/exec-mem.s b/src/platform/posix/exec-mem.s
new file mode 100644
index 000000000..21115a36b
--- /dev/null
+++ b/src/platform/posix/exec-mem.s
@@ -0,0 +1,4 @@
+.section .execmem,"awx",%nobits
+.global _execMem
+_execMem:
+.space 0x800000
diff --git a/src/platform/posix/memory.c b/src/platform/posix/memory.c
index 65cdce366..5ac73697d 100644
--- a/src/platform/posix/memory.c
+++ b/src/platform/posix/memory.c
@@ -7,14 +7,23 @@
 
 #include <sys/mman.h>
 
+extern uint32_t _execMem;
+static void* _execMemHead = &_execMem;
+
 void* anonymousMemoryMap(size_t size) {
 	return mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
 }
 
 void* executableMemoryMap(size_t size) {
-	return mmap(0, size, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANON, -1, 0);
+	void* out = _execMemHead;
+	_execMemHead += size / sizeof(_execMemHead);
+	return out;
 }
 
 void mappedMemoryFree(void* memory, size_t size) {
+	if (memory < _execMemHead + 0x20000) {
+		_execMemHead -= size / sizeof(_execMemHead);
+		return;
+	}
 	munmap(memory, size);
 }