rtld: avoid division in __thr_map_stacks_exec()

(cherry picked from commit 31f688a26d82ce00d1ec7ca9ed17b9914bf5176f)

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

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libthr: extract code to get main stack base and size into helpers

Reviewed by: brooks, imp (previous version)
Discussed with: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differenti

libthr: extract code to get main stack base and size into helpers

Reviewed by: brooks, imp (previous version)
Discussed with: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D36540

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libc, libthr: use AT_USRSTACK{BASE,LIM} instead of sysctl("kern.usrstack") and get_rlimit(RLIMIT_STACK)

Reviewed by: brooks, imp (previous version)
Discussed with: markj
Sponsored by: The FreeBSD Fo

libc, libthr: use AT_USRSTACK{BASE,LIM} instead of sysctl("kern.usrstack") and get_rlimit(RLIMIT_STACK)

Reviewed by: brooks, imp (previous version)
Discussed with: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D36540

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libthr: use nitems() for mib length

Suggested by: imp
Reviewed by: brooks, imp (previous version)
Discussed with: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision:

libthr: use nitems() for mib length

Suggested by: imp
Reviewed by: brooks, imp (previous version)
Discussed with: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D36540

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Revert "libthr: Use kern.stacktop for thread stack calculation."

The current ASLR stack gap feature will be removed, and with that the
need for this change, and the kern.stactop sysctl, is gone. Mo

Revert "libthr: Use kern.stacktop for thread stack calculation."

The current ASLR stack gap feature will be removed, and with that the
need for this change, and the kern.stactop sysctl, is gone. Moreover,
the approach taken in this revision does not provide compatibility for
old copies of libthr.so, and the revision should have also updated
__libc_map_stacks_exec().

This reverts commit 78df56ccfcb40013a3e6904bd6d39836220c3550.

Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33704

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libthr: Use kern.stacktop for thread stack calculation.

Use the new kern.stacktop sysctl to retrieve the address of stack top
instead of kern.usrstack. kern.usrstack does not have any knowledge
of t

libthr: Use kern.stacktop for thread stack calculation.

Use the new kern.stacktop sysctl to retrieve the address of stack top
instead of kern.usrstack. kern.usrstack does not have any knowledge
of the stack gap, so this can cause problems with thread stacks.
Using kern.stacktop sysctl should fix most of those problems.
kern.usrstack is used as a fallback when kern.stacktop cannot be read.

Rename usrstack variables to stacktop to reflect this change.

Fixes problems with firefox and thunderbird not starting with
stack gap enabled.

PR: 239873
Reviewed by: kib
Obtained from: Semihalf
Sponsored by: Stormshield
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D31898

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lib: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
pr

lib: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

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libthr: Use CLI flags instead of pragmas to disable warnings

People tweaking the build system or compilers tend to look into
the Makefile and not into the source. Having some warning controls
in th

libthr: Use CLI flags instead of pragmas to disable warnings

People tweaking the build system or compilers tend to look into
the Makefile and not into the source. Having some warning controls
in the Makefile and some in the source code is surprising.

Pragmas have the advantage that they leave the warnings enabled
for more code, but that advantage isn't very relevant in these cases.

Requested by: kib
Reviewed by: kib
MFC after: 3 days
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D10832

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libthr: fix warnings at WARNS=6

Fix warnings about the following when WARNS=6 (which I will commit soon):

- casting away const
- no previous 'extern' declaration for non-static variable
- others as

libthr: fix warnings at WARNS=6

Fix warnings about the following when WARNS=6 (which I will commit soon):

- casting away const
- no previous 'extern' declaration for non-static variable
- others as explained by #pragmas and comments
- unused parameters

The last is the only functional change.

Reviewed by: kib
MFC after: 3 days
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D10808

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Use __FBSDID() for .c files from lib/libthr/thread.

Sponsored by: The FreeBSD Foundation

If libthr.so is dlopened without RTLD_GLOBAL flag, the libthr symbols
do not participate in the global symbols namespace, but rtld locks are
still replaced and functions are interposed. In particula

If libthr.so is dlopened without RTLD_GLOBAL flag, the libthr symbols
do not participate in the global symbols namespace, but rtld locks are
still replaced and functions are interposed. In particular,
__pthread_map_stacks_exec is resolved to the libc version. If a
library is loaded later, which requires adjustment of the stack
protection mode, rtld calls into libc __pthread_map_stacks_exec due to
the symbols scope. The libc version might recurse into binder and
recursively acquire rtld bind lock, causing the hang.

Make libc __pthread_map_stacks_exec() interposed, which synchronizes
rtld locks and version of the stack exec hook when libthr loaded,
regardless of the symbol scope control or symbol resolution order.

The __pthread_map_stacks_exec() symbol is removed from the private
version in libthr since libc symbol now operates correctly in presence
of libthr.

Reported and tested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

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Add a knob LIBPTHREAD_BIGSTACK_MAIN, which instructs libthr to leave
the whole RLIMIT_STACK-sized region of the kernel-allocated stack as
the stack of main thread.

By default, the main thread stack

Add a knob LIBPTHREAD_BIGSTACK_MAIN, which instructs libthr to leave
the whole RLIMIT_STACK-sized region of the kernel-allocated stack as
the stack of main thread.

By default, the main thread stack is clamped at 2MB (4MB on 64bit
ABIs) and the rest is used for other threads stack allocation. Since
there is no programmatic way to adjust the size of the main thread
stack, pthread_attr_setstacksize() is too late, the knob allows user
to manage the main stack size both for single-threaded and
multi-threaded processes with the rlimit.

Reported by: "Ivan A. Kosarev" <[email protected]>
Tested by: dim
Sponsored by: The FreeBSD Foundation
MFC after: 3 days

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Style.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

For the process that already loaded libthr but still not initialized
threading, fall back to libc method of performing
__pthread_map_stacks_exec() job.

Reported and tested by: Mykola Dzham <i levsha

For the process that already loaded libthr but still not initialized
threading, fall back to libc method of performing
__pthread_map_stacks_exec() job.

Reported and tested by: Mykola Dzham <i levsha me>

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Implement the __pthread_map_stacks_exec() for libthr.

Stack creation code is changed to call _rtld_get_stack_prot() to get
the stack protection right. There is a race where thread is created
during

Implement the __pthread_map_stacks_exec() for libthr.

Stack creation code is changed to call _rtld_get_stack_prot() to get
the stack protection right. There is a race where thread is created
during dlopen() of dso that requires executable stacks. Then,
_rtld_get_stack_prot() may return PROT_READ | PROT_WRITE, but thread
is still not linked into the thread list. In this case, the callback
misses the thread stack, and rechecks the required protection
afterward.

Reviewed by: davidxu

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Convert thread list lock from mutex to rwlock.

WARNS level 4 cleanup.

Import my recent 1:1 threading working. some features improved includes:
1. fast simple type mutex.
2. __thread tls works.
3. asynchronous cancellation works ( using signal ).
4. thread synchroni

Import my recent 1:1 threading working. some features improved includes:
1. fast simple type mutex.
2. __thread tls works.
3. asynchronous cancellation works ( using signal ).
4. thread synchronization is fully based on umtx, mainly, condition
variable and other synchronization objects were rewritten by using
umtx directly. those objects can be shared between processes via
shared memory, it has to change ABI which does not happen yet.
5. default stack size is increased to 1M on 32 bits platform, 2M for
64 bits platform.
As the result, some mysql super-smack benchmarks show performance is
improved massivly.

Okayed by: jeff, mtm, rwatson, scottl

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Increase the default stacksizes:

32-bit 64-bit
main thread 2 MB 4 MB
other threads 1 MB 2 MB

Approved by: mtm
Adapted from: libpthread

Don't include sys/user.h merely for its side-effect of recursively
including other headers.

Decouple the thread stack [de]allocating functions from the 'dead threads list'
lock. It's not really necessary and we don't need the added complexity
or potential for deadlocks.

Approved by: re/bla

Decouple the thread stack [de]allocating functions from the 'dead threads list'
lock. It's not really necessary and we don't need the added complexity
or potential for deadlocks.

Approved by: re/blanket libthr

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Start locking up the active and dead threads lists. The active threads
list is protected by a spinlock_t, but the dead list uses a pthread_mutex
because it is necessary to synchronize other threads w

Start locking up the active and dead threads lists. The active threads
list is protected by a spinlock_t, but the dead list uses a pthread_mutex
because it is necessary to synchronize other threads with the garbage
collector thread. Lock/Unlock macros are used so it's easier to make
changes to the locks in the future.

The 'dead thread list' lock is intended to replace the gc mutex.
This doesn't have any practical ramifications. It simply makes it
clearer what the purpose of the lock is. The gc will use this lock,
instead of the gc mutex, to synchronize access to the dead list with
other threads.

Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK,
and also to properly lock and protect thread state changes,
especially with respect to a joining thread.

The gc thread was also re-arranged to be more organized and less nested.

_pthread_join() was also modified to use the thread list locks. However,
locking and unlocking here needs special care because a thread could find
itself in a position where it's joining an exiting thread that is
waiting on the dead list lock, which this thread (joiner) holds. If the
joiner doesn't take care to lock *and* unlock in the same order they
(the joiner and the joinee) could deadlock against each other.

Approved by: re/blanket libthr

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- Add libthr but don't hook it up to the regular build yet. This is an
adaptation of libc_r for the thr system call interface. This is beta
quality code.