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ThreadManager: Fix mmap usage to not take guest space

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SHM stats and CallRet stack was accidentally using system mmap which
means it would take VA space from the guest. Ensure it uses the
Allocator helpers so that doesn't happen.

Gives 32-bit guests 8-ish megabyte of VA space back.
This commit is contained in:
Ryan Houdek committed 2025-10-06 11:20:00 -07:00
1 parent 2017100ff3
commit 2cab87fbd0
1 file changed
+8 -7
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Source/Tools/LinuxEmulation/LinuxSyscalls/ThreadManager.cpp
+8 -7
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@@ -46,7 +46,7 @@ void ThreadManager::StatAlloc::Initialize() {
// 1 page: 99 slots
// 1 MB: 26211 slots
// 128 MB: 3355440 slots
Base = ::mmap(nullptr, MAX_STATS_SIZE, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
Base = FEXCore::Allocator::mmap(nullptr, MAX_STATS_SIZE, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
if (Base == MAP_FAILED) {
LogMan::Msg::EFmt("[StatAlloc] mmap base failed");
Base = nullptr;
@@ -55,10 +55,10 @@ void ThreadManager::StatAlloc::Initialize() {
// Allocate a small working shared space for now, grow as necessary.
{
auto SharedBase = ::mmap(Base, CurrentSize, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, fd, 0);
auto SharedBase = FEXCore::Allocator::mmap(Base, CurrentSize, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, fd, 0);
if (SharedBase == MAP_FAILED) {
LogMan::Msg::EFmt("[StatAlloc] mmap shm failed");
munmap(Base, MAX_STATS_SIZE);
FEXCore::Allocator::munmap(Base, MAX_STATS_SIZE);
Base = nullptr;
goto err;
}
@@ -89,7 +89,7 @@ uint32_t ThreadManager::StatAlloc::FrontendAllocateSlots(uint32_t NewSize) {
}
{
auto SharedBase = ::mmap(Base, NewSize, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, fd, 0);
auto SharedBase = FEXCore::Allocator::mmap(Base, NewSize, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, fd, 0);
if (SharedBase == MAP_FAILED) {
LogMan::Msg::EFmt("[StatAlloc] allocate more mmap shm failed");
goto err;
@@ -140,7 +140,7 @@ void ThreadManager::StatAlloc::UnlockAfterFork(FEXCore::Core::InternalThreadStat
// shm_memory ownership is retained by the parent process, so the child must replace it with its own one.
// Otherwise this process will keep reporting in the original parent thread's stats region.
munmap(Base, MAX_STATS_SIZE);
FEXCore::Allocator::munmap(Base, MAX_STATS_SIZE);
Base = nullptr;
CurrentSize = 0;
Head = nullptr;
@@ -173,7 +173,8 @@ FEX::HLE::ThreadStateObject* ThreadManager::CreateThread(uint64_t InitialRIP, ui
auto Frame = ThreadStateObject->Thread->CurrentFrame;
// Allocate the call-ret stack with guard pages on both sides
auto AllocBase = reinterpret_cast<uint64_t>(::mmap(nullptr, CALLRET_STACK_ALLOC_SIZE, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
auto AllocBase =
reinterpret_cast<uint64_t>(FEXCore::Allocator::mmap(nullptr, CALLRET_STACK_ALLOC_SIZE, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
// Set the base used for invalidation to the start past the guard pages
ThreadStateObject->Thread->CallRetStackBase = reinterpret_cast<void*>(AllocBase + FEXCore::Utils::FEX_PAGE_SIZE);
::mprotect(ThreadStateObject->Thread->CallRetStackBase, FEXCore::Core::InternalThreadState::CALLRET_STACK_SIZE, PROT_READ | PROT_WRITE);
@@ -273,7 +274,7 @@ void ThreadManager::HandleThreadDeletion(FEX::HLE::ThreadStateObject* Thread, bo
}
// Free the call-ret stack
::munmap(reinterpret_cast<void*>(Thread->GetCallRetStackInfo().AllocationBase), CALLRET_STACK_ALLOC_SIZE);
FEXCore::Allocator::munmap(reinterpret_cast<void*>(Thread->GetCallRetStackInfo().AllocationBase), CALLRET_STACK_ALLOC_SIZE);
// If the LDT segment exists then deallocate it.
if (Thread->ldt_entry_count) {