shadPS4/src/Core/Memory.cpp

#include "../Core/PS4/Loader/Elf.h"
#include "Memory.h"

#ifdef _WIN64
	#include <windows.h>
#else
	#include <sys/mman.h>
#endif

#if !defined(_WIN64)
enum PosixPageProtection
{
	PAGE_NOACCESS = 0,
    PAGE_READONLY          = PROT_READ,
    PAGE_READWRITE         = PROT_READ | PROT_WRITE,
    PAGE_EXECUTE           = PROT_EXEC,
    PAGE_EXECUTE_READ      = PROT_EXEC | PROT_READ,
    PAGE_EXECUTE_READWRITE = PROT_EXEC | PROT_READ | PROT_WRITE
};
#endif

#include "../Util/Log.h"

namespace Memory
{
	namespace VirtualMemory {
		static u32 convertMemoryMode(MemoryMode mode)
		{
			switch (mode)
			{
				case MemoryMode::Read: return PAGE_READONLY;
				case MemoryMode::Write:
				case MemoryMode::ReadWrite: return PAGE_READWRITE;

				case MemoryMode::Execute: return PAGE_EXECUTE;
				case MemoryMode::ExecuteRead: return PAGE_EXECUTE_READ;
				case MemoryMode::ExecuteWrite:
				case MemoryMode::ExecuteReadWrite: return PAGE_EXECUTE_READWRITE;

				case MemoryMode::NoAccess: return PAGE_NOACCESS;
				default:
					return PAGE_NOACCESS;
			}
		}
        static MemoryMode convertMemoryMode(u32 mode) {
            switch (mode) {
                case PAGE_NOACCESS: return MemoryMode::NoAccess;
                case PAGE_READONLY: return MemoryMode::Read;
                case PAGE_READWRITE: return MemoryMode::ReadWrite;
                case PAGE_EXECUTE: return MemoryMode::Execute;
                case PAGE_EXECUTE_READ: return MemoryMode::ExecuteRead;
                case PAGE_EXECUTE_READWRITE: return MemoryMode::ExecuteReadWrite;
                default: return MemoryMode::NoAccess;
            }
        }

		u64 memory_alloc(u64 address, u64 size, MemoryMode mode)
		{
			#ifdef _WIN64
				auto ptr = reinterpret_cast<uintptr_t>(VirtualAlloc(reinterpret_cast<LPVOID>(static_cast<uintptr_t>(address)), 
																    size,
																	static_cast<DWORD>(MEM_COMMIT) | static_cast<DWORD>(MEM_RESERVE),
																	convertMemoryMode(mode)));

				if (ptr == 0)
				{
					auto err = static_cast<u32>(GetLastError());
					LOG_ERROR_IF(true, "VirtualAlloc() failed: 0x{:X}\n", err);
				}
			#else
				auto ptr = reinterpret_cast<uintptr_t>(mmap(reinterpret_cast<void *>(static_cast<uintptr_t>(address)),
															size,
															PROT_EXEC | PROT_READ | PROT_WRITE,
															MAP_ANONYMOUS | MAP_PRIVATE,
															-1,
															0));

				if (ptr == reinterpret_cast<uintptr_t>MAP_FAILED)
				{
					LOG_ERROR_IF(true, "mmap() failed: {}\n", std::strerror(errno));
				}
			#endif
			return ptr;
		}
        bool memory_protect(u64 address, u64 size, MemoryMode mode, MemoryMode* old_mode) {
            DWORD old_protect = 0;
            if (VirtualProtect(reinterpret_cast<LPVOID>(static_cast<uintptr_t>(address)), size, convertMemoryMode(mode), &old_protect) == 0) {
                    auto err = static_cast<u32>(GetLastError());
                    LOG_ERROR_IF(true, "VirtualProtect() failed: 0x{:X}\n", err);
                    return false;
            }
            if (old_mode != nullptr) {
                    *old_mode = convertMemoryMode(old_protect);
            }
            return true;
        }

		bool memory_flush(u64 address, u64 size) {
            if (::FlushInstructionCache(GetCurrentProcess(), reinterpret_cast<LPVOID>(static_cast<uintptr_t>(address)), size) == 0) {
                    auto err = static_cast<u32>(GetLastError());
                    LOG_ERROR_IF(true, "FlushInstructionCache() failed: 0x{:X}\n", err);
                    return false;
            }
            return true;
        }
        bool memory_patch(u64 vaddr, u64 value) {
            MemoryMode old_mode{};
            memory_protect(vaddr, 8, MemoryMode::ReadWrite, &old_mode);

            auto* ptr = reinterpret_cast<uint64_t*>(vaddr);

            bool ret = (*ptr != value);

            *ptr = value;

            memory_protect(vaddr, 8, old_mode, nullptr);

			//if mode is executable flush it so insure that cpu finds it
			if ((old_mode == MemoryMode::Execute || old_mode == MemoryMode::ExecuteRead || old_mode == MemoryMode::ExecuteWrite ||
                 old_mode == MemoryMode::ExecuteReadWrite)) {
                    memory_flush(vaddr, 8);
            }

            return ret;
        }
	}
}