vasilito
068a1ca63e
Bootloader fork rebase:
- Base changed from 0.1.0 pre-patched archive to upstream 1.0.0 tag (c7eeb9f)
- Applied 0001-redbear-local-forks.patch (Cargo.toml crate path redirects)
- Applied fix-uefi-alloc-panic.patch equivalents (4 panic!() -> graceful
error handling in src/main.rs)
- Applied P5-live-preload-cap-1gib.patch (1 GiB cap on live image preload)
- Skipped: P0 GPT partition scan (requires new module + integration),
P1 timeout/default-resolution, P2 live preload guard (subsumed by
panic fixes + cap), P3 live image safe read, P4 large ISO boot,
redox.patch — to be applied in dedicated rebase session.
firmware-loader/Cargo.toml: version 0.1.0 -> 0.3.0 (sync with other
Red Bear custom crates which are at 0.3.0).
fork-upstream-map.toml: bootloader back from PENDING_REBASE to 1.0.0
since the partial rebase matches upstream 1.0.0 content.
fork-upstream-map.toml: base restored to 'main' tracked (was correctly
tracked by build-redbear.sh).
106 lines
4.7 KiB
C
106 lines
4.7 KiB
C
/* Once-only control (native Windows implementation).
|
|
Copyright (C) 2005-2025 Free Software Foundation, Inc.
|
|
|
|
This file is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as
|
|
published by the Free Software Foundation; either version 2.1 of the
|
|
License, or (at your option) any later version.
|
|
|
|
This file is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
/* Written by Bruno Haible <bruno@clisp.org>, 2005.
|
|
Based on GCC's gthr-win32.h. */
|
|
|
|
#include <config.h>
|
|
|
|
/* Specification. */
|
|
#include "windows-once.h"
|
|
|
|
#include <stdlib.h>
|
|
|
|
void
|
|
glwthread_once (glwthread_once_t *once_control, void (*initfunction) (void))
|
|
{
|
|
if (once_control->inited <= 0)
|
|
{
|
|
InterlockedIncrement (&once_control->num_threads);
|
|
/* If once_control->started is == -1, set it to 0. */
|
|
if (InterlockedCompareExchange (&once_control->started, 0, -1) < 0)
|
|
{
|
|
/* This thread is the first one to come to this once_control. */
|
|
InitializeCriticalSection (&once_control->lock);
|
|
EnterCriticalSection (&once_control->lock);
|
|
once_control->inited = 0;
|
|
initfunction ();
|
|
once_control->inited = 1;
|
|
LeaveCriticalSection (&once_control->lock);
|
|
}
|
|
else
|
|
{
|
|
/* Some other thread has already started the initialization.
|
|
Yield the CPU while waiting for the other thread to finish
|
|
initializing and taking the lock. */
|
|
while (once_control->inited < 0)
|
|
Sleep (0);
|
|
if (once_control->inited <= 0)
|
|
{
|
|
/* Take the lock. This blocks until the other thread has
|
|
finished calling the initfunction. */
|
|
EnterCriticalSection (&once_control->lock);
|
|
LeaveCriticalSection (&once_control->lock);
|
|
if (!(once_control->inited > 0))
|
|
abort ();
|
|
}
|
|
}
|
|
/* Here once_control->started == 0 and once_control->inited > 0. */
|
|
if (InterlockedDecrement (&once_control->num_threads) == 0)
|
|
/* once_control->num_threads is now zero, and
|
|
once_control->started == 0 and once_control->inited > 0.
|
|
No other thread will need to use the lock.
|
|
We can therefore destroy the lock, to free resources. */
|
|
/* If once_control->inited is == 1, set it to 2. */
|
|
if (InterlockedCompareExchange (&once_control->inited, 2, 1) == 1)
|
|
DeleteCriticalSection (&once_control->lock);
|
|
}
|
|
/* Proof of correctness:
|
|
* num_threads is incremented and then decremented by some threads.
|
|
Therefore, num_threads always stays >= 0, and is == 0 at the end.
|
|
* The first thread to go through the once_control->started fence
|
|
initializes the lock and moves inited from <= 0 to > 0. The other
|
|
threads don't move inited from <= 0 to > 0.
|
|
* started, once == 0, stays == 0.
|
|
* inited, once > 0, stays > 0 (since at the place where it is assigned 0,
|
|
it cannot be > 0).
|
|
* inited does not change any more once it is 2.
|
|
Therefore, it can be changed from 1 to 2 only once.
|
|
* DeleteCriticalSection gets invoked right after inited has been changed
|
|
from 1 to 2. Therefore, DeleteCriticalSection gets invoked only once.
|
|
* After a moment where num_threads was 0 and started was 0 and
|
|
inited was > 0, no thread can reach an InitializeCriticalSection or
|
|
EnterCriticalSection invocation. Proof:
|
|
- At such a moment, no thread is in the code range between
|
|
InterlockedIncrement (&once_control->num_threads)
|
|
and
|
|
InterlockedDecrement (&once_control->num_threads)
|
|
- After such a moment, some thread can increment num_threads, but from
|
|
there they cannot reach the InitializeCriticalSection invocation,
|
|
because the once_control->started test prevents that, and they cannot
|
|
reach the EnterCriticalSection invocation in the other branch because
|
|
the
|
|
if (once_control->inited <= 0)
|
|
test prevents that.
|
|
* From this it follows that:
|
|
- DeleteCriticalSection cannot be executed while the lock is taken
|
|
(because DeleteCriticalSection is only executed after a moment where
|
|
num_threads was 0 and started was 0 and inited was > 0).
|
|
- Once DeleteCriticalSection has been executed, the lock is not used any
|
|
more.
|
|
*/
|
|
}
|