1 files changed, 304 insertions, 0 deletions
diff --git a/src/common/src/mem_arena.cpp b/src/common/src/mem_arena.cpp
new file mode 100644
index 00000000..13cd00fd
--- /dev/null
+++ b/src/common/src/mem_arena.cpp
@@ -0,0 +1,304 @@
+// Copyright 2013 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+
+#include "common.h"
+#include "memory_util.h"
+#include "mem_arena.h"
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <cerrno>
+#include <cstring>
+#ifdef ANDROID
+#include <sys/ioctl.h>
+#include <linux/ashmem.h>
+#endif
+#endif
+#include <set>
+
+#if defined(__APPLE__)
+static const char* ram_temp_file = "/tmp/gc_mem.tmp";
+#elif !defined(_WIN32) // non OSX unixes
+static const char* ram_temp_file = "/dev/shm/gc_mem.tmp";
+#endif
+#ifdef ANDROID
+#define ASHMEM_DEVICE "/dev/ashmem"
+
+int AshmemCreateFileMapping(const char *name, size_t size)
+{
+	int fd, ret;
+	fd = open(ASHMEM_DEVICE, O_RDWR);
+	if (fd < 0)
+		return fd;
+
+	// We don't really care if we can't set the name, it is optional	
+	ret = ioctl(fd, ASHMEM_SET_NAME, name);
+
+	ret = ioctl(fd, ASHMEM_SET_SIZE, size);
+	if (ret < 0)
+	{
+		close(fd);
+		NOTICE_LOG(MEMMAP, "Ashmem returned error: 0x%08x", ret);
+		return ret;
+	}
+	return fd;
+}
+#endif
+
+void MemArena::GrabLowMemSpace(size_t size)
+{
+#ifdef _WIN32
+	hMemoryMapping = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, (DWORD)(size), NULL);
+#elif defined(ANDROID)
+	fd = AshmemCreateFileMapping("Dolphin-emu", size);
+	if (fd < 0)
+	{
+		NOTICE_LOG(MEMMAP, "Ashmem allocation failed");
+		return;
+	}
+#else
+	mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
+	fd = open(ram_temp_file, O_RDWR | O_CREAT, mode);
+	unlink(ram_temp_file);
+	if (ftruncate(fd, size) < 0)
+		ERROR_LOG(MEMMAP, "Failed to allocate low memory space");
+	return;
+#endif
+}
+
+
+void MemArena::ReleaseSpace()
+{
+#ifdef _WIN32
+	CloseHandle(hMemoryMapping);
+	hMemoryMapping = 0;
+#else
+	close(fd);
+#endif
+}
+
+
+void *MemArena::CreateView(s64 offset, size_t size, void *base)
+{
+#ifdef _WIN32
+	return MapViewOfFileEx(hMemoryMapping, FILE_MAP_ALL_ACCESS, 0, (DWORD)((u64)offset), size, base);
+#else
+	void *retval = mmap(
+		base, size,
+		PROT_READ | PROT_WRITE,
+		MAP_SHARED | ((base == nullptr) ? 0 : MAP_FIXED),
+		fd, offset);
+
+	if (retval == MAP_FAILED)
+	{
+		NOTICE_LOG(MEMMAP, "mmap on %s failed", ram_temp_file);
+		return nullptr;
+	}
+	else
+	{
+		return retval;
+	}
+#endif
+}
+
+
+void MemArena::ReleaseView(void* view, size_t size)
+{
+#ifdef _WIN32
+	UnmapViewOfFile(view);
+#else
+	munmap(view, size);
+#endif
+}
+
+
+u8* MemArena::Find4GBBase()
+{
+#ifdef _M_X64
+#ifdef _WIN32
+	// 64 bit
+	u8* base = (u8*)VirtualAlloc(0, 0xE1000000, MEM_RESERVE, PAGE_READWRITE);
+	VirtualFree(base, 0, MEM_RELEASE);
+	return base;
+#else
+	// Very precarious - mmap cannot return an error when trying to map already used pages.
+	// This makes the Windows approach above unusable on Linux, so we will simply pray...
+	return reinterpret_cast<u8*>(0x2300000000ULL);
+#endif
+
+#else
+	// 32 bit
+#ifdef _WIN32
+	// The highest thing in any 1GB section of memory space is the locked cache. We only need to fit it.
+	u8* base = (u8*)VirtualAlloc(0, 0x31000000, MEM_RESERVE, PAGE_READWRITE);
+	if (base) {
+		VirtualFree(base, 0, MEM_RELEASE);
+	}
+	return base;
+#else
+#ifdef ANDROID
+	// Android 4.3 changed how mmap works.
+	// if we map it private and then munmap it, we can't use the base returned.
+	// This may be due to changes in them support a full SELinux implementation.
+	const int flags = MAP_ANON;
+#else
+	const int flags = MAP_ANON | MAP_PRIVATE;
+#endif
+	const u32 MemSize = 0x31000000;
+	void* base = mmap(0, MemSize, PROT_NONE, flags, -1, 0);
+	if (base == MAP_FAILED) {
+		PanicAlert("Failed to map 1 GB of memory space: %s", strerror(errno));
+		return 0;
+	}
+	munmap(base, MemSize);
+	return static_cast<u8*>(base);
+#endif
+#endif
+}
+
+
+// yeah, this could also be done in like two bitwise ops...
+#define SKIP(a_flags, b_flags) \
+	if (!(a_flags & MV_WII_ONLY) && (b_flags & MV_WII_ONLY)) \
+		continue; \
+	if (!(a_flags & MV_FAKE_VMEM) && (b_flags & MV_FAKE_VMEM)) \
+		continue; \
+
+
+static bool Memory_TryBase(u8 *base, const MemoryView *views, int num_views, u32 flags, MemArena *arena) {
+	// OK, we know where to find free space. Now grab it!
+	// We just mimic the popular BAT setup.
+	u32 position = 0;
+	u32 last_position = 0;
+
+	// Zero all the pointers to be sure.
+	for (int i = 0; i < num_views; i++)
+	{
+		if (views[i].out_ptr_low)
+			*views[i].out_ptr_low = 0;
+		if (views[i].out_ptr)
+			*views[i].out_ptr = 0;
+	}
+
+	int i;
+	for (i = 0; i < num_views; i++)
+	{
+		SKIP(flags, views[i].flags);
+		if (views[i].flags & MV_MIRROR_PREVIOUS) {
+			position = last_position;
+		} else {
+			*(views[i].out_ptr_low) = (u8*)arena->CreateView(position, views[i].size);
+			if (!*views[i].out_ptr_low)
+				goto bail;
+		}
+#ifdef _M_X64
+		*views[i].out_ptr = (u8*)arena->CreateView(
+			position, views[i].size, base + views[i].virtual_address);
+#else
+		if (views[i].flags & MV_MIRROR_PREVIOUS) {
+			// No need to create multiple identical views.
+			*views[i].out_ptr = *views[i - 1].out_ptr;
+		} else {
+			*views[i].out_ptr = (u8*)arena->CreateView(
+				position, views[i].size, base + (views[i].virtual_address & 0x3FFFFFFF));
+			if (!*views[i].out_ptr)
+				goto bail;
+		}
+#endif
+		last_position = position;
+		position += views[i].size;
+	}
+
+	return true;
+
+bail:
+	// Argh! ERROR! Free what we grabbed so far so we can try again.
+	MemoryMap_Shutdown(views, i+1, flags, arena);
+	return false;
+}
+
+u8 *MemoryMap_Setup(const MemoryView *views, int num_views, u32 flags, MemArena *arena)
+{
+	u32 total_mem = 0;
+	int base_attempts = 0;
+
+	for (int i = 0; i < num_views; i++)
+	{
+		SKIP(flags, views[i].flags);
+		if ((views[i].flags & MV_MIRROR_PREVIOUS) == 0)
+			total_mem += views[i].size;
+	}
+	// Grab some pagefile backed memory out of the void ...
+	arena->GrabLowMemSpace(total_mem);
+
+	// Now, create views in high memory where there's plenty of space.
+#ifdef _M_X64
+	u8 *base = MemArena::Find4GBBase();
+	// This really shouldn't fail - in 64-bit, there will always be enough
+	// address space.
+	if (!Memory_TryBase(base, views, num_views, flags, arena))
+	{
+		PanicAlert("MemoryMap_Setup: Failed finding a memory base.");
+		exit(0);
+		return 0;
+	}
+#else
+#ifdef _WIN32
+	// Try a whole range of possible bases. Return once we got a valid one.
+	u32 max_base_addr = 0x7FFF0000 - 0x31000000;
+	u8 *base = NULL;
+
+	for (u32 base_addr = 0x40000; base_addr < max_base_addr; base_addr += 0x40000)
+	{
+		base_attempts++;
+		base = (u8 *)base_addr;
+		if (Memory_TryBase(base, views, num_views, flags, arena)) 
+		{
+			INFO_LOG(MEMMAP, "Found valid memory base at %p after %i tries.", base, base_attempts);
+			base_attempts = 0;
+			break;
+		}
+		
+	}
+#else
+	// Linux32 is fine with the x64 method, although limited to 32-bit with no automirrors.
+	u8 *base = MemArena::Find4GBBase();
+	if (!Memory_TryBase(base, views, num_views, flags, arena))
+	{
+		PanicAlert("MemoryMap_Setup: Failed finding a memory base.");
+		exit(0);
+		return 0;
+	}
+#endif
+
+#endif
+	if (base_attempts)
+		PanicAlert("No possible memory base pointer found!");
+	return base;
+}
+
+void MemoryMap_Shutdown(const MemoryView *views, int num_views, u32 flags, MemArena *arena)
+{
+	std::set<void*> freeset;
+	for (int i = 0; i < num_views; i++)
+	{
+		const MemoryView* view = &views[i];
+		u8** outptrs[2] = {view->out_ptr_low, view->out_ptr};
+		for (int j = 0; j < 2; j++)
+		{
+			u8** outptr = outptrs[j];
+			if (outptr && *outptr && !freeset.count(*outptr))
+			{
+				arena->ReleaseView(*outptr, view->size);
+				freeset.insert(*outptr);
+				*outptr = NULL;
+			}
+		}
+	}
+}