Common: Use Mach VM routines for memory mapping

MacOS does not support an equivalent of MAP_FIXED_NOREPLACE via mmap(),
which means that our usage for allocating PCSX2's memory map is not
thread-safe.

common/Darwin/DarwinMisc.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2002-2023 PCSX2 Dev Team
+// SPDX-FileCopyrightText: 2002-2024 PCSX2 Dev Team
 // SPDX-License-Identifier: LGPL-3.0+
 
 #if defined(__APPLE__)
@@ -9,14 +9,21 @@
 #include <cstring>
 #include <cstdlib>
 #include <optional>
+#include <sys/mman.h>
 #include <sys/types.h>
 #include <sys/sysctl.h>
 #include <time.h>
+#include <mach/mach_init.h>
+#include <mach/mach_port.h>
 #include <mach/mach_time.h>
+#include <mach/mach_vm.h>
+#include <mach/vm_map.h>
 #include <IOKit/pwr_mgt/IOPMLib.h>
 
-#include "common/Pcsx2Types.h"
+#include "common/Assertions.h"
+#include "common/BitUtils.h"
 #include "common/Console.h"
+#include "common/Pcsx2Types.h"
 #include "common/HostSys.h"
 #include "common/Threading.h"
 #include "common/WindowInfo.h"
@@ -181,4 +188,217 @@ std::vector<DarwinMisc::CPUClass> DarwinMisc::GetCPUClasses()
 	return out;
 }
 
+static __ri vm_prot_t MachProt(const PageProtectionMode& mode)
+{
+	vm_prot_t machmode = (mode.CanWrite()) ? VM_PROT_WRITE : 0;
+	machmode |= (mode.CanRead()) ? VM_PROT_READ : 0;
+	machmode |= (mode.CanExecute()) ? (VM_PROT_EXECUTE | VM_PROT_READ) : 0;
+	return machmode;
+}
+
+void* HostSys::Mmap(void* base, size_t size, const PageProtectionMode& mode)
+{
+	pxAssertMsg((size & (__pagesize - 1)) == 0, "Size is page aligned");
+	if (mode.IsNone())
+		return nullptr;
+
+#ifdef __aarch64__
+	// We can't allocate executable memory with mach_vm_allocate() on Apple Silicon.
+	// Instead, we need to use MAP_JIT with mmap(), which does not support fixed mappings.
+	if (mode.CanExecute())
+	{
+		if (base)
+			return nullptr;
+
+		const u32 mmap_prot = mode.CanWrite() ? (PROT_READ | PROT_WRITE | PROT_EXEC) : (PROT_READ | PROT_EXEC);
+		const u32 flags = MAP_PRIVATE | MAP_ANON | MAP_JIT;
+		void* const res = mmap(nullptr, size, mmap_prot, flags, -1, 0);
+		return (res == MAP_FAILED) ? nullptr : res;
+	}
+#endif
+
+	kern_return_t ret = mach_vm_allocate(mach_task_self(), reinterpret_cast<mach_vm_address_t*>(&base), size,
+		base ? VM_FLAGS_FIXED : VM_FLAGS_ANYWHERE);
+	if (ret != KERN_SUCCESS)
+	{
+		DEV_LOG("mach_vm_allocate() returned {}", ret);
+		return nullptr;
+	}
+
+	ret = mach_vm_protect(mach_task_self(), reinterpret_cast<mach_vm_address_t>(base), size, false, MachProt(mode));
+	if (ret != KERN_SUCCESS)
+	{
+		DEV_LOG("mach_vm_protect() returned {}", ret);
+		mach_vm_deallocate(mach_task_self(), reinterpret_cast<mach_vm_address_t>(base), size);
+		return nullptr;
+	}
+
+	return base;
+}
+
+void HostSys::Munmap(void* base, size_t size)
+{
+	if (!base)
+		return;
+
+	mach_vm_deallocate(mach_task_self(), reinterpret_cast<mach_vm_address_t>(base), size);
+}
+
+void HostSys::MemProtect(void* baseaddr, size_t size, const PageProtectionMode& mode)
+{
+	pxAssertMsg((size & (__pagesize - 1)) == 0, "Size is page aligned");
+
+	kern_return_t res = mach_vm_protect(mach_task_self(), reinterpret_cast<mach_vm_address_t>(baseaddr), size, false,
+		MachProt(mode));
+	if (res != KERN_SUCCESS) [[unlikely]]
+	{
+		ERROR_LOG("mach_vm_protect() failed: {}", res);
+		pxFailRel("mach_vm_protect() failed");
+	}
+}
+
+std::string HostSys::GetFileMappingName(const char* prefix)
+{
+	// name actually is not used.
+	return {};
+}
+
+void* HostSys::CreateSharedMemory(const char* name, size_t size)
+{
+	mach_vm_size_t vm_size = size;
+	mach_port_t port;
+	const kern_return_t res = mach_make_memory_entry_64(
+		mach_task_self(), &vm_size, 0, MAP_MEM_NAMED_CREATE | VM_PROT_READ | VM_PROT_WRITE, &port, MACH_PORT_NULL);
+	if (res != KERN_SUCCESS)
+	{
+		ERROR_LOG("mach_make_memory_entry_64() failed: {}", res);
+		return nullptr;
+	}
+
+	return reinterpret_cast<void*>(static_cast<uintptr_t>(port));
+}
+
+void HostSys::DestroySharedMemory(void* ptr)
+{
+	mach_port_deallocate(mach_task_self(), static_cast<mach_port_t>(reinterpret_cast<uintptr_t>(ptr)));
+}
+
+void* HostSys::MapSharedMemory(void* handle, size_t offset, void* baseaddr, size_t size, const PageProtectionMode& mode)
+{
+	mach_vm_address_t ptr = reinterpret_cast<mach_vm_address_t>(baseaddr);
+	const kern_return_t res = mach_vm_map(mach_task_self(), &ptr, size, 0, baseaddr ? VM_FLAGS_FIXED : VM_FLAGS_ANYWHERE,
+		static_cast<mach_port_t>(reinterpret_cast<uintptr_t>(handle)), offset, FALSE,
+		MachProt(mode), VM_PROT_READ | VM_PROT_WRITE, VM_INHERIT_NONE);
+	if (res != KERN_SUCCESS)
+	{
+		ERROR_LOG("mach_vm_map() failed: {}", res);
+		return nullptr;
+	}
+
+	return reinterpret_cast<void*>(ptr);
+}
+
+void HostSys::UnmapSharedMemory(void* baseaddr, size_t size)
+{
+	const kern_return_t res = mach_vm_deallocate(mach_task_self(), reinterpret_cast<mach_vm_address_t>(baseaddr), size);
+	if (res != KERN_SUCCESS)
+		pxFailRel("Failed to unmap shared memory");
+}
+
+#ifdef _M_ARM64
+
+void HostSys::FlushInstructionCache(void* address, u32 size)
+{
+	__builtin___clear_cache(reinterpret_cast<char*>(address), reinterpret_cast<char*>(address) + size);
+}
+
+#endif
+
+SharedMemoryMappingArea::SharedMemoryMappingArea(u8* base_ptr, size_t size, size_t num_pages)
+	: m_base_ptr(base_ptr)
+	, m_size(size)
+	, m_num_pages(num_pages)
+{
+}
+
+SharedMemoryMappingArea::~SharedMemoryMappingArea()
+{
+	pxAssertRel(m_num_mappings == 0, "No mappings left");
+
+	if (mach_vm_deallocate(mach_task_self(), reinterpret_cast<mach_vm_address_t>(m_base_ptr), m_size) != KERN_SUCCESS)
+		pxFailRel("Failed to release shared memory area");
+}
+
+
+std::unique_ptr<SharedMemoryMappingArea> SharedMemoryMappingArea::Create(size_t size)
+{
+	pxAssertRel(Common::IsAlignedPow2(size, __pagesize), "Size is page aligned");
+
+	mach_vm_address_t alloc;
+	const kern_return_t res =
+		mach_vm_map(mach_task_self(), &alloc, size, 0, VM_FLAGS_ANYWHERE,
+			MEMORY_OBJECT_NULL, 0, false, VM_PROT_NONE, VM_PROT_NONE, VM_INHERIT_NONE);
+	if (res != KERN_SUCCESS)
+	{
+		ERROR_LOG("mach_vm_map() failed: {}", res);
+		return {};
+	}
+
+	return std::unique_ptr<SharedMemoryMappingArea>(new SharedMemoryMappingArea(reinterpret_cast<u8*>(alloc), size, size / __pagesize));
+}
+
+u8* SharedMemoryMappingArea::Map(void* file_handle, size_t file_offset, void* map_base, size_t map_size, const PageProtectionMode& mode)
+{
+	pxAssert(static_cast<u8*>(map_base) >= m_base_ptr && static_cast<u8*>(map_base) < (m_base_ptr + m_size));
+
+	const kern_return_t res =
+		mach_vm_map(mach_task_self(), reinterpret_cast<mach_vm_address_t*>(&map_base), map_size, 0, VM_FLAGS_OVERWRITE,
+			static_cast<mach_port_t>(reinterpret_cast<uintptr_t>(file_handle)), file_offset, false,
+			MachProt(mode), VM_PROT_READ | VM_PROT_WRITE, VM_INHERIT_NONE);
+	if (res != KERN_SUCCESS) [[unlikely]]
+	{
+		ERROR_LOG("mach_vm_map() failed: {}", res);
+		return nullptr;
+	}
+
+	m_num_mappings++;
+	return static_cast<u8*>(map_base);
+}
+
+bool SharedMemoryMappingArea::Unmap(void* map_base, size_t map_size)
+{
+	pxAssert(static_cast<u8*>(map_base) >= m_base_ptr && static_cast<u8*>(map_base) < (m_base_ptr + m_size));
+
+	const kern_return_t res =
+		mach_vm_map(mach_task_self(), reinterpret_cast<mach_vm_address_t*>(&map_base), map_size, 0, VM_FLAGS_OVERWRITE,
+			MEMORY_OBJECT_NULL, 0, false, VM_PROT_NONE, VM_PROT_NONE, VM_INHERIT_NONE);
+	if (res != KERN_SUCCESS) [[unlikely]]
+	{
+		ERROR_LOG("mach_vm_map() failed: {}", res);
+		return false;
+	}
+
+	m_num_mappings--;
+	return true;
+}
+
+#ifdef _M_ARM64
+
+static thread_local int s_code_write_depth = 0;
+
+void HostSys::BeginCodeWrite()
+{
+	if ((s_code_write_depth++) == 0)
+		pthread_jit_write_protect_np(0);
+}
+
+void HostSys::EndCodeWrite()
+{
+	pxAssert(s_code_write_depth > 0);
+	if ((--s_code_write_depth) == 0)
+		pthread_jit_write_protect_np(1);
+}
+
+#endif
+
 #endif

common/Linux/LnxHostSys.cpp

@@ -29,14 +29,6 @@
 #define MAP_ANONYMOUS MAP_ANON
 #endif
 
-// MacOS does not have MAP_FIXED_NOREPLACE, which means our mappings are
-// vulnerable to races with the main/Qt threads. TODO: Investigate using
-// mach_vm_allocate()/mach_vm_map() instead of mmap(), but Apple's
-// documentation for these routines is non-existant...
-#if defined(__APPLE__) && !defined(MAP_FIXED_NOREPLACE)
-#define MAP_FIXED_NOREPLACE MAP_FIXED
-#endif
-
 // FreeBSD does not have MAP_FIXED_NOREPLACE, but does have MAP_EXCL.
 // MAP_FIXED combined with MAP_EXCL behaves like MAP_FIXED_NOREPLACE.
 #if defined(__FreeBSD__) && !defined(MAP_FIXED_NOREPLACE)
@@ -230,6 +222,8 @@ bool PageFaultHandler::Install(Error* error)
 	return true;
 }
 
+#ifndef __APPLE__
+
 static __ri uint LinuxProt(const PageProtectionMode& mode)
 {
 	u32 lnxmode = 0;
@@ -406,23 +400,6 @@ bool SharedMemoryMappingArea::Unmap(void* map_base, size_t map_size)
 	return true;
 }
 
-#endif
+#endif // __APPLE__
-
-#if defined(_M_ARM64) && defined(__APPLE__)
-
-static thread_local int s_code_write_depth = 0;
-
-void HostSys::BeginCodeWrite()
-{
-	if ((s_code_write_depth++) == 0)
-		pthread_jit_write_protect_np(0);
-}
-
-void HostSys::EndCodeWrite()
-{
-	pxAssert(s_code_write_depth > 0);
-	if ((--s_code_write_depth) == 0)
-		pthread_jit_write_protect_np(1);
-}
 
 #endif