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Make _Thread_local work across platforms

Browse source 
We now rewrite the binary image at runtime on Windows and XNU to change
mov %fs:0,%reg instructions to use %gs instead. There's also simpler
threading API introduced by this change and it's called _spawn() and
_join(), which has replaced most clone() usage.
This commit is contained in:
Justine Tunney 2022-07-10 04:01:17 -07:00
parent e4d6e263d4
commit 5f4f6b0e69
51 changed files with 808 additions and 1043 deletions
Download patch file Download diff file Expand all files Collapse all files

133
libc/thread/create.c
View file

@ -1,133 +0,0 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/atomic.h"
#include "libc/calls/calls.h"
#include "libc/calls/strace.internal.h"
#include "libc/errno.h"
#include "libc/intrin/setjmp.internal.h"
#include "libc/macros.internal.h"
#include "libc/nexgen32e/threaded.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/clone.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/thread/internal.h"
#include "libc/thread/thread.h"
STATIC_YOINK("_main_thread_ctor");
static cthread_t cthread_allocate(const cthread_attr_t *attr) {
char *mem;
size_t size;
cthread_t td;
size = ROUNDUP(
attr->stacksize +
ROUNDUP((uintptr_t)_tls_size + sizeof(struct cthread_descriptor_t),
PAGESIZE),
FRAMESIZE);
mem = mmap(0, size, PROT_READ | PROT_WRITE, MAP_STACK | MAP_ANONYMOUS, -1, 0);
if (mem == MAP_FAILED) return 0;
if (attr->guardsize > PAGESIZE) {
mprotect(mem, attr->guardsize, PROT_NONE);
}
td = (cthread_t)(mem + size - sizeof(struct cthread_descriptor_t));
td->self = td;
td->self2 = td;
td->err = errno;
td->tid = -1;
td->stack.bottom = mem;
td->stack.top = mem + attr->stacksize;
td->alloc.bottom = mem;
td->alloc.top = mem + size;
if (attr->mode & CTHREAD_CREATE_DETACHED) {
td->state = cthread_detached;
} else {
td->state = cthread_started;
}
// Initialize TLS with content of .tdata section
memmove((void *)((intptr_t)td - (intptr_t)_tls_size), _tdata_start,
(intptr_t)_tdata_size);
return td;
}
static int cthread_start(void *arg) {
axdx_t rc;
void *exitcode;
cthread_t td = arg;
if (!(rc = setlongerjmp(td->exiter)).ax) {
exitcode = td->func(td->arg);
} else {
exitcode = (void *)rc.dx;
}
td->exitcode = exitcode;
_pthread_key_destruct(td->key);
if (atomic_load(&td->state) & cthread_detached) {
// we're still using the stack
// thus we can't munmap it yet
// kick the can down the road!
cthread_zombies_add(td);
}
atomic_fetch_add(&td->state, cthread_finished);
return 0;
}
/**
* Creates thread.
*
* @param ptd will receive pointer to new thread descriptor
* @param attr contains special configuration if non-null
* @param func is thread callback function
* @param arg is argument supplied to `func`
* @return 0 on success, or error number on failure
* @threadsafe
*/
int cthread_create(cthread_t *ptd, const cthread_attr_t *attr,
void *(*func)(void *), void *arg) {
int rc, tid;
cthread_t td;
cthread_attr_t default_attr;
__threaded = true;
cthread_zombies_reap();
cthread_attr_init(&default_attr);
if ((td = cthread_allocate(attr ? attr : &default_attr))) {
td->func = func;
td->arg = arg;
cthread_attr_destroy(&default_attr);
tid =
clone(cthread_start, td->stack.bottom, td->stack.top - td->stack.bottom,
CLONE_THREAD | CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
CLONE_SETTLS | CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID,
td, 0, td, sizeof(struct cthread_descriptor_t), &td->tid);
if (tid != -1) {
*ptd = td;
rc = 0;
} else {
rc = errno;
munmap(td->alloc.bottom, td->alloc.top - td->alloc.bottom);
}
} else {
rc = errno;
tid = -1;
}
STRACE("cthread_create([%d], %p, %p, %p) → %s", tid, attr, func, arg,
!rc ? "0" : strerrno(rc));
return rc;
}

2
libc/thread/ctor.S
View file

@ -21,7 +21,7 @@
.init.start 400,_main_thread_ctor
push %rdi
push %rsi
call _main_thread_init
call __enable_tls
pop %rsi
pop %rdi
.init.end 400,_main_thread_ctor

72
libc/thread/join.c
View file

@ -1,72 +0,0 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/atomic.h"
#include "libc/calls/calls.h"
#include "libc/calls/strace.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/asan.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/futex.h"
#include "libc/sysv/consts/nr.h"
#include "libc/thread/thread.h"
/**
* Waits for thread to terminate and frees its memory.
*
* @param td is thread descriptor memory
* @param exitcode optionally receives value returned by thread
* @return 0 on success, or error number on failure
* @raises EDEADLK when trying to join this thread
* @raises EINVAL if another thread is joining
* @raises ESRCH if no such thread exists
* @raises EINVAL if not joinable
* @threadsafe
*/
int cthread_join(cthread_t td, void **exitcode) {
int x, rc, tid;
// otherwise, tid could be set to 0 even though `state` is not
// finished mark thread as joining
if (!td || (IsAsan() && !__asan_is_valid(td, sizeof(*td)))) {
rc = ESRCH;
tid = -1;
} else if ((tid = td->tid) == gettid()) { // tid must load before lock xadd
rc = EDEADLK;
} else if (atomic_load(&td->state) & (cthread_detached | cthread_joining)) {
rc = EINVAL;
} else {
if (~atomic_fetch_add(&td->state, cthread_joining) & cthread_finished) {
while ((x = atomic_load(&td->tid))) {
cthread_memory_wait32(&td->tid, x, 0);
}
}
if (exitcode) {
*exitcode = td->exitcode;
}
if (!munmap(td->alloc.bottom, td->alloc.top - td->alloc.bottom)) {
rc = 0;
} else {
rc = errno;
}
}
STRACE("cthread_join(%d, [%p]) → %s", tid, !rc && exitcode ? *exitcode : 0,
!rc ? "0" : strerrno(rc));
return rc;
}

68
libc/thread/init.c → libc/thread/mktls.c
View file

@ -1,7 +1,7 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
@ -16,53 +16,41 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/errno.h"
#include "libc/macros.internal.h"
#include "libc/nexgen32e/threaded.h"
#include "libc/mem/mem.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/stack.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/thread/spawn.h"
#include "libc/thread/thread.h"
textstartup void _main_thread_init(void) {
_Static_assert(offsetof(struct cthread_descriptor_t, self) == 0x00, "");
_Static_assert(offsetof(struct cthread_descriptor_t, self2) == 0x30, "");
_Static_assert(offsetof(struct cthread_descriptor_t, tid) == 0x38, "");
_Static_assert(offsetof(struct cthread_descriptor_t, err) == 0x3c, "");
cthread_t td;
size_t totalsize;
char *mem, *bottom, *top;
#define _TLSZ ((intptr_t)_tls_size)
#define _TLDZ ((intptr_t)_tdata_size)
#define _TIBZ sizeof(struct cthread_descriptor_t)
#define _MEMZ ROUNDUP(_TLSZ + _TIBZ, alignof(struct cthread_descriptor_t))
totalsize = ROUNDUP(
(uintptr_t)_tls_size + sizeof(struct cthread_descriptor_t), FRAMESIZE);
/**
* Allocates thread-local storage memory for new thread.
* @return buffer that must be released with free()
*/
char *_mktls(char **out_tib) {
char *tls;
cthread_t tib;
mem = mmap(0, totalsize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE,
-1, 0);
assert(mem != MAP_FAILED);
// Allocate enough TLS memory for all the GNU Linuker (_tls_size)
// organized _Thread_local data, as well as Cosmpolitan Libc (64)
if (!(tls = calloc(1, _MEMZ))) return 0;
bottom = mem;
top = mem + totalsize;
// set up thread informaiton block
tib = (cthread_t)(tls + _MEMZ - _TIBZ);
tib->self = tib;
tib->self2 = tib;
tib->err = 0;
tib->tid = -1;
memmove(tls, _tdata_start, _TLDZ);
td = (cthread_t)(top - sizeof(struct cthread_descriptor_t));
td->self = td;
td->self2 = td;
td->err = errno;
td->tid = gettid();
td->alloc.bottom = bottom;
td->alloc.top = top;
td->stack.bottom = GetStackAddr(0);
td->stack.top = td->stack.bottom + GetStackSize();
td->state = cthread_main;
// Initialize TLS with content of .tdata section
memmove((void *)((uintptr_t)td - (uintptr_t)_tls_size), _tdata_start,
(uintptr_t)_tdata_size);
// Set FS
__install_tls((char *)td);
if (out_tib) {
*out_tib = (char *)tib;
}
return tls;
}

113
libc/thread/spawn.c Normal file
View file

@ -0,0 +1,113 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/wait0.internal.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/nexgen32e/threaded.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/stack.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/clone.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/thread/spawn.h"
#include "libc/thread/thread.h"
STATIC_YOINK("_main_thread_ctor");
/**
* @fileoverview Simple System Threads API
*/
#define _TLSZ ((intptr_t)_tls_size)
#define _TLDZ ((intptr_t)_tdata_size)
#define _TIBZ sizeof(struct cthread_descriptor_t)
#define _MEMZ ROUNDUP(_TLSZ + _TIBZ, alignof(struct cthread_descriptor_t))
/**
* Spawns thread.
*
* @param fun is thread worker callback, which receives `arg` and `ctid`
* @param arg shall be passed to `fun`
* @param opt_out_thread needn't be initialiized and is always clobbered
* except when it isn't specified, in which case, the thread is kind
* of detached and will leak in stack / tls memory
* @return 0 on success, or -1 w/ errno
*/
int _spawn(int fun(void *, int), void *arg, struct spawn *opt_out_thread) {
struct spawn *th, ths;
// we need to to clobber the output memory before calling clone, since
// there's no guarantee clone() won't suspend the parent, and focus on
// running the child instead; in that case child might want to read it
if (opt_out_thread) {
th = opt_out_thread;
} else {
th = &ths;
}
// Allocate enough TLS memory for all the GNU Linuker (_tls_size)
// organized _Thread_local data, as well as Cosmpolitan Libc (64)
if (!(th->tls = _mktls(&th->tib))) {
return -1;
}
th->ctid = (int *)(th->tib + 0x38);
// We must use _mapstack() to allocate the stack because OpenBSD has
// very strict requirements for what's allowed to be used for stacks
if (!(th->stk = _mapstack())) {
free(th->tls);
return -1;
}
if (clone(fun, th->stk, GetStackSize(),
CLONE_VM | CLONE_THREAD | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_SETTID |
CLONE_CHILD_CLEARTID,
arg, &th->ptid, th->tib, _TIBZ, th->ctid) == -1) {
_freestack(th->stk);
free(th->tls);
return -1;
}
return 0;
}
/**
* Waits for thread created by _spawn() to terminate.
*
* This will free your thread's stack and tls memory too.
*/
int _join(struct spawn *th) {
int rc;
if (th->ctid) {
// wait for ctid to become zero
_wait0(th->ctid);
// free thread memory
free(th->tls);
rc = munmap(th->stk, GetStackSize());
} else {
rc = 0;
}
bzero(th, sizeof(*th));
return rc;
}

20
libc/thread/spawn.h Normal file
View file

@ -0,0 +1,20 @@
#ifndef COSMOPOLITAN_LIBC_THREAD_SPAWN_H_
#define COSMOPOLITAN_LIBC_THREAD_SPAWN_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
struct spawn {
int ptid;
int *ctid;
char *stk;
char *tls;
char *tib;
};
int _spawn(int (*)(void *, int), void *, struct spawn *) hidden;
int _join(struct spawn *) hidden;
char *_mktls(char **) hidden;
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_THREAD_SPAWN_H_ */

1
libc/thread/thread.h
View file

@ -15,7 +15,6 @@ enum cthread_state {
cthread_joining = 1,
cthread_finished = 2,
cthread_detached = 4,
cthread_main = 127,
};
struct cthread_descriptor_t {