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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
commit | 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /toolkit/xre/dllservices/mozglue/interceptor/VMSharingPolicies.h | |
parent | Initial commit. (diff) | |
download | thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.tar.xz thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'toolkit/xre/dllservices/mozglue/interceptor/VMSharingPolicies.h')
-rw-r--r-- | toolkit/xre/dllservices/mozglue/interceptor/VMSharingPolicies.h | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/toolkit/xre/dllservices/mozglue/interceptor/VMSharingPolicies.h b/toolkit/xre/dllservices/mozglue/interceptor/VMSharingPolicies.h new file mode 100644 index 0000000000..8f93f5c1ad --- /dev/null +++ b/toolkit/xre/dllservices/mozglue/interceptor/VMSharingPolicies.h @@ -0,0 +1,285 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ + +#ifndef mozilla_interceptor_VMSharingPolicies_h +#define mozilla_interceptor_VMSharingPolicies_h + +#include "mozilla/Assertions.h" +#include "mozilla/Attributes.h" +#include "mozilla/Maybe.h" +#include "mozilla/Types.h" + +namespace mozilla { +namespace interceptor { + +/** + * This class is an abstraction of a reservation of virtual address space that + * has been obtained from a VMSharingPolicy via the policy's |Reserve| method. + * + * TrampolinePool allows us to obtain a trampoline without needing to concern + * ourselves with the underlying implementation of the VM sharing policy. + * + * For example, VMSharingPolicyShared delegates to VMSharingPolicyUnique, but + * also requires taking a lock before doing so. By invoking |GetNextTrampoline| + * on a TrampolinePool, the caller does not need to concern themselves with + * that detail. + * + * We accompolish this with a recursive implementation that provides an inner + * TrampolinePool that is provided by the delegated VMSharingPolicy. + */ +template <typename VMPolicyT, typename InnerT> +class MOZ_STACK_CLASS TrampolinePool final { + public: + TrampolinePool(TrampolinePool&& aOther) = default; + + TrampolinePool(VMPolicyT& aVMPolicy, InnerT&& aInner) + : mVMPolicy(aVMPolicy), mInner(std::move(aInner)) {} + + TrampolinePool& operator=(TrampolinePool&& aOther) = delete; + TrampolinePool(const TrampolinePool&) = delete; + TrampolinePool& operator=(const TrampolinePool&) = delete; + + using MMPolicyT = typename VMPolicyT::MMPolicyT; + + Maybe<Trampoline<MMPolicyT>> GetNextTrampoline() { + return mVMPolicy.GetNextTrampoline(mInner); + } + +#if defined(_M_X64) + bool IsInLowest2GB() const { + return mVMPolicy.IsTrampolineSpaceInLowest2GB(mInner); + } +#endif // defined(_M_X64) + + private: + VMPolicyT& mVMPolicy; + InnerT mInner; +}; + +/** + * This specialization is the base case for TrampolinePool, and is used by + * VMSharingPolicyUnique (since that policy does not delegate anything). + */ +template <typename VMPolicyT> +class MOZ_STACK_CLASS TrampolinePool<VMPolicyT, decltype(nullptr)> final { + public: + explicit TrampolinePool(VMPolicyT& aVMPolicy) : mVMPolicy(aVMPolicy) {} + + TrampolinePool(TrampolinePool&& aOther) = default; + + TrampolinePool& operator=(TrampolinePool&& aOther) = delete; + TrampolinePool(const TrampolinePool&) = delete; + TrampolinePool& operator=(const TrampolinePool&) = delete; + + using MMPolicyT = typename VMPolicyT::MMPolicyT; + + Maybe<Trampoline<MMPolicyT>> GetNextTrampoline() { + return mVMPolicy.GetNextTrampoline(); + } + +#if defined(_M_X64) + bool IsInLowest2GB() const { + return mVMPolicy.IsTrampolineSpaceInLowest2GB(); + } +#endif // defined(_M_X64) + + private: + VMPolicyT& mVMPolicy; +}; + +template <typename MMPolicy> +class VMSharingPolicyUnique : public MMPolicy { + using ThisType = VMSharingPolicyUnique<MMPolicy>; + + public: + using PoolType = TrampolinePool<ThisType, decltype(nullptr)>; + + template <typename... Args> + explicit VMSharingPolicyUnique(Args&&... aArgs) + : MMPolicy(std::forward<Args>(aArgs)...), mNextChunkIndex(0) {} + + Maybe<PoolType> Reserve(const uintptr_t aPivotAddr, + const uint32_t aMaxDistanceFromPivot) { + // Win32 allocates VM addresses at a 64KiB granularity, so we might as well + // utilize that entire 64KiB reservation. + uint32_t len = MMPolicy::GetAllocGranularity(); + + Maybe<Span<const uint8_t>> maybeBounds = MMPolicy::SpanFromPivotAndDistance( + len, aPivotAddr, aMaxDistanceFromPivot); + + return Reserve(len, maybeBounds); + } + + Maybe<PoolType> Reserve(const uint32_t aSize, + const Maybe<Span<const uint8_t>>& aBounds) { + uint32_t bytesReserved = MMPolicy::Reserve(aSize, aBounds); + if (!bytesReserved) { + return Nothing(); + } + + return Some(PoolType(*this)); + } + + TrampolineCollection<MMPolicy> Items() const { + return TrampolineCollection<MMPolicy>(*this, this->GetLocalView(), + this->GetRemoteView(), kChunkSize, + mNextChunkIndex); + } + + void Clear() { mNextChunkIndex = 0; } + + ~VMSharingPolicyUnique() = default; + + VMSharingPolicyUnique(const VMSharingPolicyUnique&) = delete; + VMSharingPolicyUnique& operator=(const VMSharingPolicyUnique&) = delete; + + VMSharingPolicyUnique(VMSharingPolicyUnique&& aOther) + : MMPolicy(std::move(aOther)), mNextChunkIndex(aOther.mNextChunkIndex) { + aOther.mNextChunkIndex = 0; + } + + VMSharingPolicyUnique& operator=(VMSharingPolicyUnique&& aOther) { + static_cast<MMPolicy&>(*this) = std::move(aOther); + mNextChunkIndex = aOther.mNextChunkIndex; + aOther.mNextChunkIndex = 0; + return *this; + } + + protected: + // In VMSharingPolicyUnique we do not implement the overload that accepts + // an inner trampoline pool, as this policy is expected to be the + // implementation of the base case. + Maybe<Trampoline<MMPolicy>> GetNextTrampoline() { + uint32_t offset = mNextChunkIndex * kChunkSize; + if (!this->MaybeCommitNextPage(offset, kChunkSize)) { + return Nothing(); + } + + Trampoline<MMPolicy> result(this, this->GetLocalView() + offset, + this->GetRemoteView() + offset, kChunkSize); + if (!!result) { + ++mNextChunkIndex; + } + + return Some(std::move(result)); + } + + private: + uint32_t mNextChunkIndex; + static const uint32_t kChunkSize = 128; + + template <typename VMPolicyT, typename FriendT> + friend class TrampolinePool; +}; + +} // namespace interceptor +} // namespace mozilla + +// We don't include RangeMap.h until this point because it depends on the +// TrampolinePool definitions from above. +#include "mozilla/interceptor/RangeMap.h" + +namespace mozilla { +namespace interceptor { + +// We only support this policy for in-proc MMPolicy. +class MOZ_TRIVIAL_CTOR_DTOR VMSharingPolicyShared : public MMPolicyInProcess { + typedef VMSharingPolicyUnique<MMPolicyInProcess> UniquePolicyT; + typedef VMSharingPolicyShared ThisType; + + public: + using PoolType = TrampolinePool<ThisType, UniquePolicyT::PoolType>; + using MMPolicyT = MMPolicyInProcess; + + constexpr VMSharingPolicyShared() {} + + bool ShouldUnhookUponDestruction() const { return false; } + + Maybe<PoolType> Reserve(const uintptr_t aPivotAddr, + const uint32_t aMaxDistanceFromPivot) { + // Win32 allocates VM addresses at a 64KiB granularity, so we might as well + // utilize that entire 64KiB reservation. + uint32_t len = this->GetAllocGranularity(); + + Maybe<Span<const uint8_t>> maybeBounds = + MMPolicyInProcess::SpanFromPivotAndDistance(len, aPivotAddr, + aMaxDistanceFromPivot); + + AutoCriticalSection lock(GetCS()); + VMSharingPolicyUnique<MMPolicyT>* uniquePol = sVMMap.GetPolicy(maybeBounds); + MOZ_ASSERT(uniquePol); + if (!uniquePol) { + return Nothing(); + } + + Maybe<UniquePolicyT::PoolType> maybeUnique = + uniquePol->Reserve(len, maybeBounds); + if (!maybeUnique) { + return Nothing(); + } + + return Some(PoolType(*this, std::move(maybeUnique.ref()))); + } + + TrampolineCollection<MMPolicyInProcess> Items() const { + // Since ShouldUnhookUponDestruction returns false, this can be empty + return TrampolineCollection<MMPolicyInProcess>(*this); + } + + void Clear() { + // This must be a no-op for shared VM policy; we can't have one interceptor + // wiping out trampolines for all interceptors in the process. + } + + VMSharingPolicyShared(const VMSharingPolicyShared&) = delete; + VMSharingPolicyShared(VMSharingPolicyShared&&) = delete; + VMSharingPolicyShared& operator=(const VMSharingPolicyShared&) = delete; + VMSharingPolicyShared& operator=(VMSharingPolicyShared&&) = delete; + + private: + static CRITICAL_SECTION* GetCS() { + static const bool isAlloc = []() -> bool { + DWORD flags = 0; +#if defined(RELEASE_OR_BETA) + flags |= CRITICAL_SECTION_NO_DEBUG_INFO; +#endif // defined(RELEASE_OR_BETA) + ::InitializeCriticalSectionEx(&sCS, 4000, flags); + return true; + }(); + Unused << isAlloc; + + return &sCS; + } + + // In VMSharingPolicyShared, we only implement the overload that accepts + // a VMSharingPolicyUnique trampoline pool as |aInner|, since we require the + // former policy to wrap the latter. + Maybe<Trampoline<MMPolicyInProcess>> GetNextTrampoline( + UniquePolicyT::PoolType& aInner) { + AutoCriticalSection lock(GetCS()); + return aInner.GetNextTrampoline(); + } + +#if defined(_M_X64) + bool IsTrampolineSpaceInLowest2GB( + const UniquePolicyT::PoolType& aInner) const { + AutoCriticalSection lock(GetCS()); + return aInner.IsInLowest2GB(); + } +#endif // defined(_M_X64) + + private: + template <typename VMPolicyT, typename InnerT> + friend class TrampolinePool; + + inline static RangeMap<MMPolicyInProcess> sVMMap; + inline static CRITICAL_SECTION sCS; +}; + +} // namespace interceptor +} // namespace mozilla + +#endif // mozilla_interceptor_VMSharingPolicies_h |