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Move pthread into TCB.

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This commit is contained in:
4lDO2
2024-05-01 13:40:50 +02:00
parent 326c8a6231
commit 6e86e64fdf
3 changed files with 48 additions and 62 deletions
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src/pthread/mod.rs
+33 -57
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@@ -12,7 +12,7 @@ use crate::{
header::{errno::*, pthread as header, sched::sched_param, sys_mman},
ld_so::{
linker::Linker,
tcb::{Master, Tcb},
tcb::{Master, Tcb}, ExpectTlsFree,
},
platform::{types::*, Pal, Sys},
};
@@ -23,7 +23,7 @@ const MAIN_PTHREAD_ID: usize = 1;
/// Called only by the main thread, as part of relibc_start.
pub unsafe fn init() {
let obj = Box::into_raw(Box::new(Pthread {
Tcb::current().expect_notls("no TCB present for main thread").pthread = Pthread {
waitval: Waitval::new(),
has_enabled_cancelation: AtomicBool::new(false),
has_queued_cancelation: AtomicBool::new(false),
@@ -36,17 +36,15 @@ pub unsafe fn init() {
stack_size: 0,
os_tid: UnsafeCell::new(Sys::current_os_tid()),
}));
PTHREAD_SELF.set(obj);
};
}
//static NEXT_INDEX: AtomicU32 = AtomicU32::new(FIRST_THREAD_IDX + 1);
//const FIRST_THREAD_IDX: usize = 1;
pub unsafe fn terminate_from_main_thread() {
for (_, pthread) in OS_TID_TO_PTHREAD.lock().iter() {
let _ = cancel(&*pthread.0);
for (_, tcb) in OS_TID_TO_PTHREAD.lock().iter() {
let _ = cancel(&(*tcb.0).pthread);
}
}
@@ -56,18 +54,15 @@ bitflags::bitflags! {
}
}
#[derive(Debug)]
pub struct Pthread {
waitval: Waitval<Retval>,
has_queued_cancelation: AtomicBool,
has_enabled_cancelation: AtomicBool,
flags: AtomicUsize,
pub(crate) waitval: Waitval<Retval>,
pub(crate) has_queued_cancelation: AtomicBool,
pub(crate) has_enabled_cancelation: AtomicBool,
pub(crate) flags: AtomicUsize,
// Small index (compared to pointer size) used for e.g. recursive mutexes. Zero is reserved,
// so it starts from one. The 31st bit is reserved. Only for process-private mutexes, which we
// currently don't handle separately.
//index: u32,
stack_base: *mut c_void,
stack_size: usize,
pub(crate) stack_base: *mut c_void,
pub(crate) stack_size: usize,
pub(crate) os_tid: UnsafeCell<OsTid>,
}
@@ -88,7 +83,7 @@ unsafe impl Sync for Pthread {}
// TODO: Move to a more generic place.
pub struct Errno(pub c_int);
#[derive(Clone, Copy)]
#[derive(Clone, Copy, Debug)]
pub struct Retval(pub *mut c_void);
struct MmapGuard {
@@ -116,7 +111,8 @@ pub(crate) unsafe fn create(
.expect("failed to obtain sigprocmask for caller");
// Create a locked mutex, unlocked by the thread after it has started.
let synchronization_mutex = Box::into_raw(Box::new(Mutex::locked(procmask)));
let synchronization_mutex = Mutex::locked(procmask);
let synchronization_mutex = &synchronization_mutex;
let stack_size = attrs.stacksize.next_multiple_of(Sys::getpagesize());
@@ -146,18 +142,6 @@ pub(crate) unsafe fn create(
other => unreachable!("unknown detachstate {}", other),
}
let pthread = Pthread {
waitval: Waitval::new(),
flags: flags.bits().into(),
has_enabled_cancelation: AtomicBool::new(false),
has_queued_cancelation: AtomicBool::new(false),
stack_base,
stack_size,
os_tid: UnsafeCell::new(OsTid::default()),
//index: NEXT_INDEX.fetch_add(1, Ordering::Relaxed),
};
let ptr = Box::into_raw(Box::new(pthread));
let stack_raii = MmapGuard {
page_start: stack_base,
mmap_size: stack_size,
@@ -165,6 +149,9 @@ pub(crate) unsafe fn create(
let current_tcb = Tcb::current().expect("no TCB!");
let new_tcb = Tcb::new(current_tcb.tls_len).map_err(|_| Errno(ENOMEM))?;
new_tcb.pthread.flags = flags.bits().into();
new_tcb.pthread.stack_base = stack_base;
new_tcb.pthread.stack_size = stack_size;
new_tcb.masters_ptr = current_tcb.masters_ptr;
new_tcb.masters_len = current_tcb.masters_len;
@@ -187,8 +174,8 @@ pub(crate) unsafe fn create(
push(0);
}
push(0);
push(synchronization_mutex as usize);
push(ptr as usize);
push(synchronization_mutex as *const _ as usize);
push(0);
push(new_tcb as *mut _ as usize);
push(arg as usize);
@@ -202,37 +189,37 @@ pub(crate) unsafe fn create(
};
core::mem::forget(stack_raii);
let _ = (&*synchronization_mutex).lock();
let _ = synchronization_mutex.lock();
OS_TID_TO_PTHREAD
.lock()
.insert(os_tid, ForceSendSync(ptr.cast()));
.insert(os_tid, ForceSendSync(new_tcb));
Ok(ptr.cast())
Ok((&new_tcb.pthread) as *const _ as *mut _)
}
/// A shim to wrap thread entry points in logic to set up TLS, for example
unsafe extern "C" fn new_thread_shim(
entry_point: unsafe extern "C" fn(*mut c_void) -> *mut c_void,
arg: *mut c_void,
tcb: *mut Tcb,
pthread: *mut Pthread,
_pthread: *mut Pthread,
mutex: *const Mutex<u64>,
) -> ! {
let procmask = (*mutex).as_ptr().read();
#[cfg(target_os = "redox")]
syscall::sigprocmask(syscall::SIG_SETMASK, Some(&procmask), None)
.expect("failed to set procmask in child thread");
if let Some(tcb) = tcb.as_mut() {
tcb.copy_masters().unwrap();
tcb.activate();
}
PTHREAD_SELF.set(pthread);
core::ptr::write((&*pthread).os_tid.get(), Sys::current_os_tid());
(*tcb).pthread.os_tid.get().write(Sys::current_os_tid());
(&*mutex).manual_unlock();
#[cfg(target_os = "redox")]
syscall::sigprocmask(syscall::SIG_SETMASK, Some(&procmask), None)
.expect("failed to set procmask in child thread");
let retval = entry_point(arg);
exit_current_thread(Retval(retval))
@@ -266,10 +253,8 @@ pub unsafe fn detach(thread: &Pthread) -> Result<(), Errno> {
Ok(())
}
// Returns option because that's a no-op, but PTHREAD_SELF should always be initialized except in
// early init code.
pub fn current_thread() -> Option<&'static Pthread> {
unsafe { NonNull::new(PTHREAD_SELF.get()).map(|p| p.as_ref()) }
unsafe { Tcb::current().map(|p| &p.pthread) }
}
pub unsafe fn testcancel() {
@@ -302,15 +287,9 @@ pub unsafe fn exit_current_thread(retval: Retval) -> ! {
Sys::exit_thread()
}
// TODO: Use Arc? One strong reference from each OS_TID_TO_PTHREAD and one strong reference from
// PTHREAD_SELF. The latter ref disappears when the thread exits, while the former disappears when
// detaching. Isn't that sufficient?
//
// On the other hand, there can be at most two strong references to each thread (OS_TID_TO_PTHREAD
// and PTHREAD_SELF), so maybe Arc is unnecessary except from being memory-safe.
unsafe fn dealloc_thread(thread: &Pthread) {
OS_TID_TO_PTHREAD.lock().remove(&thread.os_tid.get().read());
drop(Box::from_raw(thread as *const Pthread as *mut Pthread));
//drop(Box::from_raw(thread as *const Pthread as *mut Pthread));
}
pub const SIGRT_RLCT_CANCEL: usize = 32;
pub const SIGRT_RLCT_TIMER: usize = 33;
@@ -396,7 +375,7 @@ pub fn get_sched_param(thread: &Pthread) -> Result<(clockid_t, sched_param), Err
// TODO: Hash map?
// TODO: RwLock to improve perf?
static OS_TID_TO_PTHREAD: Mutex<BTreeMap<OsTid, ForceSendSync<*mut Pthread>>> =
static OS_TID_TO_PTHREAD: Mutex<BTreeMap<OsTid, ForceSendSync<*mut Tcb>>> =
Mutex::new(BTreeMap::new());
#[derive(Clone, Copy)]
@@ -404,9 +383,6 @@ struct ForceSendSync<T>(T);
unsafe impl<T> Send for ForceSendSync<T> {}
unsafe impl<T> Sync for ForceSendSync<T> {}
#[thread_local]
static PTHREAD_SELF: Cell<*mut Pthread> = Cell::new(core::ptr::null_mut());
/*pub(crate) fn current_thread_index() -> u32 {
current_thread().expect("current thread not present").index
}*/