RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 15:37:46 +00:00
Code Issues Activity Actions

Kernel: Some futex improvements

Browse source 
This adds support for FUTEX_WAKE_OP, FUTEX_WAIT_BITSET, FUTEX_WAKE_BITSET,
FUTEX_REQUEUE, and FUTEX_CMP_REQUEUE, as well well as global and private
futex and absolute/relative timeouts against the appropriate clock. This
also changes the implementation so that kernel resources are only used when
a thread is blocked on a futex.

Global futexes are implemented as offsets in VMObjects, so that different
processes can share a futex against the same VMObject despite potentially
being mapped at different virtual addresses.
This commit is contained in:
Tom 2020-12-21 23:21:58 -07:00 • committed by Andreas Kling
parent 7581b64705
commit 1d621ab172
23 changed files with 928 additions and 63 deletions
Download patch file Download diff file Expand all files Collapse all files

11
Kernel/Process.h
View file

@ -38,6 +38,7 @@
#include <Kernel/API/Syscall.h>
#include <Kernel/FileSystem/InodeMetadata.h>
#include <Kernel/Forward.h>
#include <Kernel/FutexQueue.h>
#include <Kernel/Lock.h>
#include <Kernel/ProcessGroup.h>
#include <Kernel/StdLib.h>
@ -94,6 +95,8 @@ enum class VeilState {
Locked,
};
typedef HashMap<FlatPtr, RefPtr<FutexQueue>> FutexQueues;
class Process
: public RefCounted<Process>
, public InlineLinkedListNode<Process>
@ -542,6 +545,8 @@ private:
bool has_tracee_thread(ProcessID tracer_pid);
void clear_futex_queues_on_exec();
RefPtr<PageDirectory> m_page_directory;
Process* m_prev { nullptr };
@ -637,11 +642,11 @@ private:
VeilState m_veil_state { VeilState::None };
UnveilNode m_unveiled_paths { "/", { .full_path = "/", .unveil_inherited_from_root = true } };
WaitQueue& futex_queue(Userspace<const i32*>);
HashMap<u32, OwnPtr<WaitQueue>> m_futex_queues;
OwnPtr<PerformanceEventBuffer> m_perf_event_buffer;
FutexQueues m_futex_queues;
SpinLock<u8> 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.