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use lots of PROT_NONE memory to reliably reserve virtual address space

This commit is contained in:
RSDuck 2024-10-30 00:04:55 +01:00
parent 2f6a740b65
commit 04fe90b437
1 changed files with 8 additions and 13 deletions
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21
src/ARMJIT_Memory.cpp
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@ -100,6 +100,9 @@
namespace melonDS
{
static constexpr u64 AddrSpaceSize = 0x100000000;
static constexpr u64 VirtmemAreaSize = AddrSpaceSize * 2 + MemoryTotalSize;
using Platform::Log;
using Platform::LogLevel;
@ -288,7 +291,7 @@ bool ARMJIT_Memory::UnmapFromRange(u32 addr, u32 num, u32 offset, u32 size) noex
#elif defined(_WIN32)
return UnmapViewOfFile(dst);
#else
return munmap(dst, size) == 0;
return mmap(dst, size, PROT_NONE, MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0) != MAP_FAILED;
#endif
}
@ -643,8 +646,6 @@ bool ARMJIT_Memory::FaultHandler(FaultDescription& faultDesc, melonDS::NDS& nds)
return false;
}
const u64 AddrSpaceSize = 0x100000000;
ARMJIT_Memory::ARMJIT_Memory(melonDS::NDS& nds) : NDS(nds)
{
#if defined(__SWITCH__)
@ -689,15 +690,9 @@ ARMJIT_Memory::ARMJIT_Memory(melonDS::NDS& nds) : NDS(nds)
MapViewOfFileEx(MemoryFile, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, MemoryTotalSize, MemoryBase);
#else
// this used to be allocated with three different mmaps
// The idea was to give the OS more freedom where to position the buffers,
// but something was bad about this so instead we take this vmem eating monster
// which seems to work better.
MemoryBase = (u8*)mmap(NULL, AddrSpaceSize*4, PROT_NONE, MAP_ANON | MAP_PRIVATE, -1, 0);
munmap(MemoryBase, AddrSpaceSize*4);
FastMem9Start = MemoryBase;
FastMem7Start = MemoryBase + AddrSpaceSize;
MemoryBase = MemoryBase + AddrSpaceSize*2;
MemoryBase = (u8*)mmap(NULL, VirtmemAreaSize, PROT_NONE, MAP_ANON | MAP_PRIVATE, -1, 0);
FastMem9Start = MemoryBase+MemoryTotalSize;
FastMem7Start = static_cast<u8*>(FastMem9Start)+AddrSpaceSize;
#if defined(__ANDROID__)
Libandroid = Platform::DynamicLibrary_Load("libandroid.so");
@ -791,7 +786,7 @@ ARMJIT_Memory::~ARMJIT_Memory() noexcept
#endif
if (MemoryBase)
{
munmap(MemoryBase, MemoryTotalSize);
munmap(MemoryBase, VirtmemAreaSize);
MemoryBase = nullptr;
FastMem9Start = nullptr;
FastMem7Start = nullptr;