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Kernel: Clean up sys$futex and add support for cross-process futexes

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This commit is contained in:
Idan Horowitz 2022-07-14 01:25:35 +03:00 • committed by Andreas Kling
parent 55c7496200
commit 9db10887a1
9 changed files with 164 additions and 70 deletions
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30
Kernel/Process.h
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@ -82,7 +82,22 @@ enum class VeilState {
Locked,
};
using FutexQueues = HashMap<FlatPtr, NonnullRefPtr<FutexQueue>>;
static constexpr FlatPtr futex_key_private_flag = 0b1;
union GlobalFutexKey {
struct {
Memory::VMObject const* vmobject;
FlatPtr offset;
} shared;
struct {
Memory::AddressSpace const* address_space;
FlatPtr user_address;
} private_;
struct {
FlatPtr parent;
FlatPtr offset;
} raw;
};
static_assert(sizeof(GlobalFutexKey) == (sizeof(FlatPtr) * 2));
struct LoadResult;
@ -575,6 +590,8 @@ private:
void clear_signal_handlers_for_exec();
void clear_futex_queues_on_exec();
ErrorOr<GlobalFutexKey> get_futex_key(FlatPtr user_address, bool shared);
ErrorOr<void> remap_range_as_stack(FlatPtr address, size_t size);
ErrorOr<FlatPtr> read_impl(int fd, Userspace<u8*> buffer, size_t size);
@ -829,9 +846,6 @@ private:
OwnPtr<PerformanceEventBuffer> m_perf_event_buffer;
FutexQueues m_futex_queues;
Spinlock m_futex_lock;
// This member is used in the implementation of ptrace's PT_TRACEME flag.
// If it is set to true, the process will stop at the next execve syscall
// and wait for a tracer to attach.
@ -1040,3 +1054,11 @@ struct AK::Formatter<Kernel::Process> : AK::Formatter<FormatString> {
return AK::Formatter<FormatString>::format(builder, "{}({})"sv, value.name(), value.pid().value());
}
};
namespace AK {
template<>
struct Traits<Kernel::GlobalFutexKey> : public GenericTraits<Kernel::GlobalFutexKey> {
static unsigned hash(Kernel::GlobalFutexKey const& futex_key) { return pair_int_hash(ptr_hash(futex_key.raw.parent), ptr_hash(futex_key.raw.offset)); }
static bool equals(Kernel::GlobalFutexKey const& a, Kernel::GlobalFutexKey const& b) { return a.raw.parent == b.raw.parent && a.raw.offset == b.raw.offset; }
};
};