Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merging of projects/armv6, part 2

Handle TLS for ARMv6 and ARMv7

- Switch to saving non-offseted pointer to TLS block in order too keep things simple

Add thread-local storage support for arm:

- Switch to Variant I TCB layout
- Use function from rtld for TCB allocation/deallocation

Switch MIPS TLS implementation to Variant I:

Save pointer to the TLS structure taking into account TP_OFFSET
and TCB structure size.

The TCB_GET32() and TCB_GET64() macros in the i386 and amd64-specific
versions of pthread_md.h have a special case of dereferencing a null
pointer. Clang warns about this with:

In file included from lib/libthr/arch/i386/i386/pthread_md.c:36:
lib/libthr/arch/i386/include/pthread_md.h:96:10: error: indirection of non-volatile null pointer will be deleted, not trap [-Werror,-Wnull-dereference]
return (TCB_GET32(tcb_self));
^~~~~~~~~~~~~~~~~~~
lib/libthr/arch/i386/include/pthread_md.h:73:13: note: expanded from:
: "m" (*(u_int *)(__tcb_offset(name)))); \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/libthr/arch/i386/include/pthread_md.h:96:10: note: consider using __builtin_trap() or qualifying pointer with 'volatile'

Since this indirection is done relative to the fs or gs segment, to
retrieve thread-specific data, it is an exception to the rule.

Therefore, add a volatile qualifier to tell the compiler we really want
to dereference a zero address.

MFC after: 1 week

Merge from r161730:
o Set TP using inline assembly to avoid dead code elimination.
o Eliminate _tcb.

Merge from r161840:
Stylize: avoid using a global register variable.

Merge from r157461:
Simplify _get_curthread() and _tcb_ctor because libc and rtld now
already allocate thread pointer space in tls block for initial thread.

Merge from r177853:
Replace function _umtx_op with _umtx_op_err, the later function directly
returns errno, because errno can be mucked by user's signal handler and
most of pthread api heavily depends on errno to be correct, this change
should improve stability of the thread library.

MFC after: 1 week

Add section .note.GNU-stack for assembly files used by 386 and amd64.

Merge from tbemd, with a small amount of rework:
For all libthr contexts, use ${MACHINE_CPUARCH}
for all libc contexts, use ${MACHINE_ARCH} if it exists, otherwise use
${MACHINE_CPUARCH}
Move some common code up a layer (the .PATH statement was the same in
all the arch submakefiles).

# Hope she hasn't busted powerpc64 with this...

Unify 32-bit and 64-bit PowerPC libthr support. This reduces code
duplication, and simplifies the TBEMD import.

Requested by: imp

Fix SVN mismerge. We somehow ended up with the 32-bit powerpc version
in arch/powerpc64 instead of the 64-bit one.

Powerpc64 thread libraries support.

Merge r195129 from project/mips to head by hand:

r195129 | gonzo | 2009-06-27 17:28:56 -0600 (Sat, 27 Jun 2009) | 2 lines
- Use sysarch(2) in MIPS version of _tcb_set/_tcb_get

Implement _umtx_op_err() for ia64.

Commit missing mips libthr support that I thought I'd committed earlier

Bring in mips threads support from perforce mips2-jnpr branch.

Replace function _umtx_op with _umtx_op_err, the later function directly
returns errno, because errno can be mucked by user's signal handler and
most of pthread api heavily depends on errno to be correct, this change
should improve stability of the thread library.

style.Makefile(5)

style(9)

- Remove variable _thr_scope_system, all threads are system scope.
- Rename _thr_smp_cpus to boolean variable _thr_is_smp.
- Define CPU_SPINWAIT macro for each arch, only X86 supports it.

Stylize: avoid using a global register variable.

Rename TLS_TP_OFFSET back to TP_OFFSET. The former clashes with rtld.

Stylize.

Stylize.

TLS fixes:
o The TLS pointer (r2) points 0x7000 after the *end* of the TCB.
o _rtld_allocate_tls() gets a pointer to the current TCB, not the
current TLS pointer.
o _rtld_free_tls() gets the size of the TCB structure.

Fix harmless bug: sizeof(tcb) equals sizeof(void*) not sizeof(struct tcb).
The argument is (currently) not used by _rtld_free_tls().

o Set TP using inline assembly to avoid dead code elimination.
o Eliminate _tcb.

Remove alpha left-overs.

Remove declaration of _thr_initial from MD header file, it is no longer
needed.

Simplify _get_curthread() and _tcb_ctor because libc and rtld now
already allocate thread pointer space in tls block for initial thread.
Only i386 and amd64 have been done, others still have to be tested.

Remove functions i386_get_gsbase and i386_set_gsbase, they were already
in libc.

Remove unused variable.

Reviewed by: cognet

Kill unused variable declaration.

Remove COMPAT_32BIT, it is no longer needed.

Remove unused variable.

Now libthr only uses GDT based tls on i386. using LDT can only increase
clock cycles and has 8191 threads limitation.

Add i386_get_gsbase, i386_set_gsbase since old libc doesn't have the
functions, otherwise user ports have to be rebuilt.

Adapt the libpthread patch for using i386_set_gsbase() to libthr.

Use the new atomic_cmpset_32().

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

Fix inverted #ifdef that I added. Who had the pointy hat last?

Submitted by: kan

Use the recently exposed fs/gs set functions when compiling libthr to
run as a 32 bit support library for an amd64 kernel. 32 bit consumers of
libthr have zero chance of running on an amd64 kernel since we don't
implement the i386_set_ldt() family of functions. Note that this commit
doesn't make it actually work, it just removes one more obstacle.

Adjust code to support AMD64, on AMD64, thread needs to set fsbase by
itself before it can execute any other code, so new thread should be
created with all signals are masked until after fsbase is set.

Add AMD64 support code.

Add TLS support for libthr on i386.

Make NULL a (void*)0 whereever possible, and fix the warnings(-Werror)
that this provokes. "Wherever possible" means "In the kernel OR NOT
C++" (implying C).

There are places where (void *) pointers are not valid, such as for
function pointers, but in the special case of (void *)0, agreement
settles on it being OK.

Most of the fixes were NULL where an integer zero was needed; many
of the fixes were NULL where ascii <nul> ('\0') was needed, and a
few were just "other".

Tested on: i386 sparc64

libthr powerpc support.

Submitted by: Suleiman Souhlal <refugee@segfaulted.com>
Tested with: most libpthread tests, Apache 'worker' MDM

Bump up the maximum number concurrent threads on x86.

Use dynamic instead of static LDT allocation.

Approved by: re (scottl)

Implement _get_curthread and _set_curthread. We use GCCs builtin
function this, which expands to PAL calls (rduniq and wruniq).
This needs adjustment when TLS is implemented.

This commit was generated by cvs2svn to compensate for changes in r117783,
which included commits to RCS files with non-trunk default branches.

The move to _retire() a thread in the GC instead of in the thread's
exit function has invalidated the need for _spin[un]lock_pthread().
The _spin[un]lock() functions can now dereference curthread without
the danger that the ldtentry containing the pointer to the thread
has been cleared out from under them.

.S comments must be C comments, not ASM ones.

Missing unlock.

Approved by: re/jhb

Return gracefully, rather than aborting, when the maximum concurrent
threads per process has been reached. Return EAGAIN, as per spec.

Approved by: re/blanket libthr

The struct mcontext has changed. It's using the register sets. Bring
this in line.

Add two functions: _spinlock_pthread() and _spinunlock_pthread()
that take the address of a struct pthread as their first argument.
_spin[un]lock() just become wrappers arround these two functions.
These new functions are for use in situations where curthread can't be
used. One example is _thread_retire(), where we invalidate the array index
curthread uses to get its pointer..

Approved by: re/blanket libthr

Make WARNS2 clean. The fixes mostly included:
o removed unused variables
o explicit inclusion of header files
o prototypes for externally defined functions

Approved by: re/blanket libthr

o Make the defenition of _set_curthread() match its declaration
in thr_private.h

o Lock down the ldt_entries array and ldt_free, which points to
the next free slot. As noted in the comments, it's necessary
to special case the initial_thread because %gs is not setup
for it yet. This is ok because that early in the program there
won't be any reentrancy issues anyways.

Approved by: re/blanket libthr

Fix a null dereference leading to a core dump when
the number of threads exceeds the number of open slots
in ldt_entries[].

Approved by: markm (mentor)(implicit)
Reviewed by: jeff

Add support for ia64.

Note that the tp register (r13) is reserved as the TLS pointer in
the same way that that gp register (r1) is reserved as the global
pointer. This implementation uses the tp register to point to the
thread structure used by the threads implementation. This is not
in violation with the runtime specification provided the TLS is
a fixed distance from the thread structure. This is only an issue
when code used the __thread keyword to create TLS. This is not
supported at the moment.

- Pass a ucontext_t to _set_curthread. If non-NULL the new thread is set
as curthread in the new context, so that it will be set automatically when
the thread is switched to. This fixes a race where we'd run for a little
while with curthread unset in _thread_start.

Reviewed by: jeff

- Don't overrun the ldt buffer.

Submitted by: gordan@freebsd.org

Implement _get_curthread and _set_curthread. This is especially easy.

Add MD makefile.

- Adjust the makefiles so we have a per architecture makefile.

- 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.