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linux(4): Reimplement futexes using umtx.

Browse Source 
Differential Revision:	https://reviews.freebsd.org/D31236
MFC after:		2 weeks
This commit is contained in:
Dmitry Chagin 2021-07-29 12:43:48 +03:00
parent 8e4d22c01d
commit 0dc38e3303
9 changed files with 136 additions and 614 deletions
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3
sys/compat/linux/linux.c
View File

@ -56,9 +56,6 @@ __FBSDID("$FreeBSD$");
#include <compat/linux/linux_mib.h>
#include <compat/linux/linux_util.h>
struct futex_list futex_list;
struct mtx futex_mtx; /* protects the futex list */
CTASSERT(LINUX_IFNAMSIZ == IFNAMSIZ);
static int bsd_to_linux_sigtbl[LINUX_SIGTBLSZ] = {

3
sys/compat/linux/linux.h
View File

@ -173,9 +173,6 @@ void bsd_to_linux_sigset(sigset_t *, l_sigset_t *);
int linux_to_bsd_signal(int sig);
int bsd_to_linux_signal(int sig);
extern LIST_HEAD(futex_list, futex) futex_list;
extern struct mtx futex_mtx;
void linux_dev_shm_create(void);
void linux_dev_shm_destroy(void);

4
sys/compat/linux/linux_common.c
View File

@ -34,7 +34,6 @@ __FBSDID("$FreeBSD$");
#include <sys/imgact_elf.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/sx.h>
#include <compat/linux/linux.h>
@ -64,15 +63,12 @@ linux_common_modevent(module_t mod, int type, void *data)
linux_osd_jail_register();
SET_FOREACH(ldhp, linux_device_handler_set)
linux_device_register_handler(*ldhp);
LIST_INIT(&futex_list);
mtx_init(&futex_mtx, "ftllk", NULL, MTX_DEF);
break;
case MOD_UNLOAD:
linux_dev_shm_destroy();
linux_osd_jail_deregister();
SET_FOREACH(ldhp, linux_device_handler_set)
linux_device_unregister_handler(*ldhp);
mtx_destroy(&futex_mtx);
break;
default:
return (EOPNOTSUPP);

9
sys/compat/linux/linux_fork.c
View File

@ -407,7 +407,6 @@ linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args
void
linux_thread_detach(struct thread *td)
{
struct linux_sys_futex_args cup;
struct linux_emuldata *em;
int *child_clear_tid;
int error;
@ -429,13 +428,7 @@ linux_thread_detach(struct thread *td)
if (error != 0)
return;
cup.uaddr = child_clear_tid;
cup.op = LINUX_FUTEX_WAKE;
cup.val = 1; /* wake one */
cup.timeout = NULL;
cup.uaddr2 = NULL;
cup.val3 = 0;
error = linux_sys_futex(td, &cup);
error = futex_wake(td, child_clear_tid, 1, false);
/*
* this cannot happen at the moment and if this happens it
* probably means there is a user space bug

721
sys/compat/linux/linux_futex.c
View File

@ -77,62 +77,21 @@ __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $")
/* DTrace init */
LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
/**
* Futex part for the special DTrace module "locks".
*/
LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
/**
* Per futex probes.
*/
LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
/**
* DTrace probes in this module.
*/
LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
"int");
LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
"int");
LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
"int");
LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
"struct waiting_proc *", "uint32_t *", "uint32_t");
LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
"struct waiting_proc *");
LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
"struct waiting_proc *", "uint32_t");
LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
"struct waiting_proc *", "uint32_t");
LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
"int");
LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_clockswitch);
LIN_SDT_PROBE_DEFINE1(futex, linux_futex, copyin_error, "int");
LIN_SDT_PROBE_DEFINE0(futex, linux_futex, invalid_cmp_requeue_use);
LIN_SDT_PROBE_DEFINE3(futex, linux_futex, debug_wait, "uint32_t *",
"uint32_t", "uint32_t");
LIN_SDT_PROBE_DEFINE4(futex, linux_futex, debug_wait_value_neq,
"uint32_t *", "uint32_t", "int", "uint32_t");
LIN_SDT_PROBE_DEFINE3(futex, linux_futex, debug_wake, "uint32_t *",
"uint32_t", "uint32_t");
LIN_SDT_PROBE_DEFINE5(futex, linux_futex, debug_cmp_requeue, "uint32_t *",
"uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
LIN_SDT_PROBE_DEFINE2(futex, linux_futex, debug_cmp_requeue_value_neq,
"uint32_t", "int");
LIN_SDT_PROBE_DEFINE5(futex, linux_futex, debug_wake_op, "uint32_t *",
"int", "uint32_t", "uint32_t *", "uint32_t");
LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unhandled_efault);
LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_lock_pi);
LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_unlock_pi);
LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_trylock_pi);
@ -146,77 +105,10 @@ LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
struct futex;
#define FUTEX_SHARED 0x8 /* shared futex */
struct waiting_proc {
uint32_t wp_flags;
struct futex *wp_futex;
TAILQ_ENTRY(waiting_proc) wp_list;
};
#define GET_SHARED(a) (a->flags & FUTEX_SHARED) ? AUTO_SHARE : THREAD_SHARE
struct futex {
struct mtx f_lck;
uint32_t *f_uaddr; /* user-supplied value, for debug */
struct umtx_key f_key;
uint32_t f_refcount;
uint32_t f_bitset;
LIST_ENTRY(futex) f_list;
TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
};
#define FUTEX_LOCK(f) mtx_lock(&(f)->f_lck)
#define FUTEX_LOCKED(f) mtx_owned(&(f)->f_lck)
#define FUTEX_UNLOCK(f) mtx_unlock(&(f)->f_lck)
#define FUTEX_INIT(f) do { \
mtx_init(&(f)->f_lck, "ftlk", NULL, \
MTX_DUPOK); \
LIN_SDT_PROBE1(futex, futex, create, \
&(f)->f_lck); \
} while (0)
#define FUTEX_DESTROY(f) do { \
LIN_SDT_PROBE1(futex, futex, destroy, \
&(f)->f_lck); \
mtx_destroy(&(f)->f_lck); \
} while (0)
#define FUTEX_ASSERT_LOCKED(f) mtx_assert(&(f)->f_lck, MA_OWNED)
#define FUTEX_ASSERT_UNLOCKED(f) mtx_assert(&(f)->f_lck, MA_NOTOWNED)
#define FUTEXES_LOCK do { \
mtx_lock(&futex_mtx); \
LIN_SDT_PROBE1(locks, futex_mtx, \
locked, &futex_mtx); \
} while (0)
#define FUTEXES_UNLOCK do { \
LIN_SDT_PROBE1(locks, futex_mtx, \
unlock, &futex_mtx); \
mtx_unlock(&futex_mtx); \
} while (0)
/* flags for futex_get() */
#define FUTEX_CREATE_WP 0x1 /* create waiting_proc */
#define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */
#define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */
#define FUTEX_SHARED 0x8 /* shared futex */
#define FUTEX_DONTLOCK 0x10 /* don't lock futex */
/* wp_flags */
#define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list
* of futex where thread sleep to wp_list
* of another futex.
*/
#define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex
* wp_list to prevent double wakeup.
*/
static void futex_put(struct futex *, struct waiting_proc *);
static int futex_get0(uint32_t *, struct futex **f, uint32_t);
static int futex_get(uint32_t *, struct waiting_proc **, struct futex **,
uint32_t);
static int futex_sleep(struct futex *, struct waiting_proc *, struct timespec *);
static int futex_wake(struct futex *, int, uint32_t);
static int futex_requeue(struct futex *, int, struct futex *, int);
static void futex_lock(struct futex *);
static void futex_unlock(struct futex *);
static int futex_atomic_op(struct thread *, int, uint32_t *);
static int handle_futex_death(struct linux_emuldata *, uint32_t *,
unsigned int);
@ -236,320 +128,27 @@ struct linux_futex_args {
struct timespec kts;
};
static void linux_umtx_abs_timeout_init(struct umtx_abs_timeout *,
struct linux_futex_args *);
static int linux_futex(struct thread *, struct linux_futex_args *);
static int linux_futex_wait(struct thread *, struct linux_futex_args *);
static int linux_futex_wake(struct thread *, struct linux_futex_args *);
static int linux_futex_requeue(struct thread *, struct linux_futex_args *);
static int linux_futex_wakeop(struct thread *, struct linux_futex_args *);
static void
futex_put(struct futex *f, struct waiting_proc *wp)
int
futex_wake(struct thread *td, uint32_t *uaddr, int val, bool shared)
{
struct linux_futex_args args;
if (wp != NULL) {
if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
free(wp, M_FUTEX_WP);
}
bzero(&args, sizeof(args));
args.op = LINUX_FUTEX_WAKE;
args.uaddr = uaddr;
args.flags = shared == true ? FUTEX_SHARED : 0;
args.val = val;
args.val3 = FUTEX_BITSET_MATCH_ANY;
FUTEXES_LOCK;
if (--f->f_refcount == 0) {
LIST_REMOVE(f, f_list);
FUTEXES_UNLOCK;
if (FUTEX_LOCKED(f))
futex_unlock(f);
LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
f->f_refcount, f->f_key.shared);
LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
"shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
umtx_key_release(&f->f_key);
FUTEX_DESTROY(f);
free(f, M_FUTEX);
return;
}
LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
f->f_key.shared);
LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
f->f_uaddr, f->f_refcount, f->f_key.shared);
if (FUTEX_LOCKED(f))
futex_unlock(f);
FUTEXES_UNLOCK;
}
static int
futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
{
struct futex *f, *tmpf;
struct umtx_key key;
int error;
*newf = tmpf = NULL;
error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
AUTO_SHARE : THREAD_SHARE, &key);
if (error) {
LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
return (error);
}
retry:
FUTEXES_LOCK;
LIST_FOREACH(f, &futex_list, f_list) {
if (umtx_key_match(&f->f_key, &key)) {
if (tmpf != NULL) {
if (FUTEX_LOCKED(tmpf))
futex_unlock(tmpf);
FUTEX_DESTROY(tmpf);
free(tmpf, M_FUTEX);
}
if (flags & FUTEX_DONTEXISTS) {
FUTEXES_UNLOCK;
umtx_key_release(&key);
return (EINVAL);
}
/*
* Increment refcount of the found futex to
* prevent it from deallocation before FUTEX_LOCK()
*/
++f->f_refcount;
FUTEXES_UNLOCK;
umtx_key_release(&key);
if ((flags & FUTEX_DONTLOCK) == 0)
futex_lock(f);
*newf = f;
LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
f->f_refcount, f->f_key.shared);
LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
uaddr, f->f_refcount, f->f_key.shared);
return (0);
}
}
if (flags & FUTEX_DONTCREATE) {
FUTEXES_UNLOCK;
umtx_key_release(&key);
LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
return (0);
}
if (tmpf == NULL) {
FUTEXES_UNLOCK;
tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
tmpf->f_uaddr = uaddr;
tmpf->f_key = key;
tmpf->f_refcount = 1;
tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
FUTEX_INIT(tmpf);
TAILQ_INIT(&tmpf->f_waiting_proc);
/*
* Lock the new futex before an insert into the futex_list
* to prevent futex usage by other.
*/
if ((flags & FUTEX_DONTLOCK) == 0)
futex_lock(tmpf);
goto retry;
}
LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
FUTEXES_UNLOCK;
LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
tmpf->f_key.shared);
LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
uaddr, tmpf->f_refcount, tmpf->f_key.shared);
*newf = tmpf;
return (0);
}
static int
futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
uint32_t flags)
{
int error;
if (flags & FUTEX_CREATE_WP) {
*wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
(*wp)->wp_flags = 0;
}
error = futex_get0(uaddr, f, flags);
if (error) {
LIN_SDT_PROBE0(futex, futex_get, error);
if (flags & FUTEX_CREATE_WP)
free(*wp, M_FUTEX_WP);
return (error);
}
if (flags & FUTEX_CREATE_WP) {
TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
(*wp)->wp_futex = *f;
}
return (error);
}
static inline void
futex_lock(struct futex *f)
{
LINUX_CTR3(sys_futex, "futex_lock uaddr %p ref %d shared %d",
f->f_uaddr, f->f_refcount, f->f_key.shared);
FUTEX_ASSERT_UNLOCKED(f);
FUTEX_LOCK(f);
}
static inline void
futex_unlock(struct futex *f)
{
LINUX_CTR3(sys_futex, "futex_unlock uaddr %p ref %d shared %d",
f->f_uaddr, f->f_refcount, f->f_key.shared);
FUTEX_ASSERT_LOCKED(f);
FUTEX_UNLOCK(f);
}
static int
futex_sleep(struct futex *f, struct waiting_proc *wp, struct timespec *ts)
{
sbintime_t sbt, prec, tmp;
time_t over;
int error;
FUTEX_ASSERT_LOCKED(f);
if (ts != NULL) {
if (ts->tv_sec > INT32_MAX / 2) {
over = ts->tv_sec - INT32_MAX / 2;
ts->tv_sec -= over;
}
tmp = tstosbt(*ts);
if (TIMESEL(&sbt, tmp))
sbt += tc_tick_sbt;
sbt += tmp;
prec = tmp;
prec >>= tc_precexp;
} else {
sbt = 0;
prec = 0;
}
LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d",
f->f_uaddr, wp, sbt, f->f_refcount);
error = msleep_sbt(wp, &f->f_lck, PCATCH, "futex", sbt, prec, C_ABSOLUTE);
if (wp->wp_flags & FUTEX_WP_REQUEUED) {
KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
if (error) {
LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
f->f_uaddr, wp, wp->wp_futex->f_uaddr,
wp->wp_futex->f_refcount);
}
LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
" %p requeued uaddr %p ref %d",
error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
wp->wp_futex->f_refcount);
futex_put(f, NULL);
f = wp->wp_futex;
futex_lock(f);
} else {
if (error) {
LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
f->f_uaddr, wp);
}
LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
error, f->f_uaddr, wp);
}
futex_put(f, wp);
return (error);
}
static int
futex_wake(struct futex *f, int n, uint32_t bitset)
{
struct waiting_proc *wp, *wpt;
int count = 0;
if (bitset == 0)
return (EINVAL);
FUTEX_ASSERT_LOCKED(f);
TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
f->f_refcount);
LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
f->f_uaddr, wp, f->f_refcount);
/*
* Unless we find a matching bit in
* the bitset, continue searching.
*/
if (!(wp->wp_futex->f_bitset & bitset))
continue;
wp->wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
wakeup_one(wp);
if (++count == n)
break;
}
return (count);
}
static int
futex_requeue(struct futex *f, int nrwake, struct futex *f2,
int nrrequeue)
{
struct waiting_proc *wp, *wpt;
int count = 0;
FUTEX_ASSERT_LOCKED(f);
FUTEX_ASSERT_LOCKED(f2);
TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
if (++count <= nrwake) {
LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
f->f_uaddr, wp);
wp->wp_flags |= FUTEX_WP_REMOVED;
TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
wakeup_one(wp);
} else {
LIN_SDT_PROBE3(futex, futex_requeue, requeue,
f->f_uaddr, wp, f2->f_uaddr);
LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
f->f_uaddr, wp, f2->f_uaddr);
wp->wp_flags |= FUTEX_WP_REQUEUED;
/* Move wp to wp_list of f2 futex */
TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
/*
* Thread which sleeps on wp after waking should
* acquire f2 lock, so increment refcount of f2 to
* prevent it from premature deallocation.
*/
wp->wp_futex = f2;
FUTEXES_LOCK;
++f2->f_refcount;
FUTEXES_UNLOCK;
if (count - nrwake >= nrrequeue)
break;
}
}
return (count);
return (linux_futex_wake(td, &args));
}
static int
@ -631,20 +230,8 @@ linux_futex(struct thread *td, struct linux_futex_args *args)
} else
args->flags = FUTEX_SHARED;
/*
* Currently support for switching between CLOCK_MONOTONIC and
* CLOCK_REALTIME is not present. However Linux forbids the use of
* FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
* FUTEX_WAIT_REQUEUE_PI.
*/
args->clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
if (args->clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
LIN_SDT_PROBE0(futex, linux_futex,
unimplemented_clockswitch);
return (ENOSYS);
}
switch (args->op) {
case LINUX_FUTEX_WAIT:
@ -785,87 +372,68 @@ linux_futex(struct thread *td, struct linux_futex_args *args)
static int
linux_futex_wakeop(struct thread *td, struct linux_futex_args *args)
{
struct umtx_key key, key2;
int nrwake, op_ret, ret;
struct futex *f, *f2;
int error, save;
uint32_t val;
int error, count;
if (args->uaddr == args->uaddr2)
return (EINVAL);
retry:
f = f2 = NULL;
error = futex_get(args->uaddr, NULL, &f, args->flags | FUTEX_DONTLOCK);
error = umtx_key_get(args->uaddr, TYPE_FUTEX, GET_SHARED(args), &key);
if (error != 0)
return (error);
error = futex_get(args->uaddr2, NULL, &f2, args->flags | FUTEX_DONTLOCK);
error = umtx_key_get(args->uaddr2, TYPE_FUTEX, GET_SHARED(args), &key2);
if (error != 0) {
futex_put(f, NULL);
umtx_key_release(&key);
return (error);
}
futex_lock(f);
futex_lock(f2);
/*
* This function returns positive number as results and
* negative as errors
*/
save = vm_fault_disable_pagefaults();
umtxq_lock(&key);
umtxq_busy(&key);
umtxq_unlock(&key);
op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
vm_fault_enable_pagefaults(save);
LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
args->uaddr, op_ret);
if (op_ret < 0) {
if (f2 != NULL)
futex_put(f2, NULL);
futex_put(f, NULL);
if (op_ret == -ENOSYS)
return (ENOSYS);
error = copyin(args->uaddr2, &val, sizeof(val));
if (error == 0)
goto retry;
return (error);
}
ret = futex_wake(f, args->val, args->val3);
if (op_ret > 0) {
op_ret = 0;
nrwake = (int)(unsigned long)args->ts;
if (f2 != NULL)
op_ret += futex_wake(f2, nrwake, args->val3);
error = ENOSYS;
else
op_ret += futex_wake(f, nrwake, args->val3);
ret += op_ret;
error = EFAULT;
}
umtxq_lock(&key);
umtxq_unbusy(&key);
if (error != 0)
goto out;
ret = umtxq_signal_mask(&key, args->val, args->val3);
if (op_ret > 0) {
nrwake = (int)(unsigned long)args->ts;
umtxq_lock(&key2);
count = umtxq_count(&key2);
if (count > 0)
ret += umtxq_signal_mask(&key2, nrwake, args->val3);
else
ret += umtxq_signal_mask(&key, nrwake, args->val3);
umtxq_unlock(&key2);
}
if (f2 != NULL)
futex_put(f2, NULL);
futex_put(f, NULL);
td->td_retval[0] = ret;
return (0);
out:
umtxq_unlock(&key);
umtx_key_release(&key2);
umtx_key_release(&key);
return (error);
}
static int
linux_futex_requeue(struct thread *td, struct linux_futex_args *args)
{
int nrwake, nrrequeue;
struct futex *f, *f2;
struct umtx_key key, key2;
int error;
uint32_t val;
uint32_t uval;
/*
* Linux allows this, we would not, it is an incorrect
* usage of declared ABI, so return EINVAL.
*/
if (args->uaddr == args->uaddr2) {
LIN_SDT_PROBE0(futex, linux_futex,
invalid_cmp_requeue_use);
if (args->uaddr == args->uaddr2)
return (EINVAL);
}
nrrequeue = (int)(unsigned long)args->ts;
nrwake = args->val;
@ -876,136 +444,121 @@ linux_futex_requeue(struct thread *td, struct linux_futex_args *args)
if (nrwake < 0 || nrrequeue < 0)
return (EINVAL);
retry:
f = f2 = NULL;
error = futex_get(args->uaddr, NULL, &f, args->flags | FUTEX_DONTLOCK);
error = umtx_key_get(args->uaddr, TYPE_FUTEX, GET_SHARED(args), &key);
if (error != 0)
return (error);
/*
* To avoid deadlocks return EINVAL if second futex
* exists at this time.
*
* Glibc fall back to FUTEX_WAKE in case of any error
* returned by FUTEX_CMP_REQUEUE.
*/
error = futex_get(args->uaddr2, NULL, &f2,
args->flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK);
error = umtx_key_get(args->uaddr2, TYPE_FUTEX, GET_SHARED(args), &key2);
if (error != 0) {
futex_put(f, NULL);
umtx_key_release(&key);
return (error);
}
futex_lock(f);
futex_lock(f2);
error = copyin_nofault(args->uaddr, &val, sizeof(val));
if (error != 0) {
futex_put(f2, NULL);
futex_put(f, NULL);
error = copyin(args->uaddr, &val, sizeof(val));
if (error == 0)
goto retry;
LIN_SDT_PROBE1(futex, linux_futex, copyin_error,
error);
LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
error);
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
umtxq_unlock(&key);
error = fueword32(args->uaddr, &uval);
if (error != 0)
error = EFAULT;
else if (args->val3_compare == true && uval != args->val3)
error = EWOULDBLOCK;
umtxq_lock(&key);
umtxq_unbusy(&key);
if (error == 0) {
umtxq_lock(&key2);
td->td_retval[0] = umtxq_requeue(&key, nrwake, &key2, nrrequeue);
umtxq_unlock(&key2);
}
if (args->val3_compare == true && val != args->val3) {
LIN_SDT_PROBE2(futex, linux_futex,
debug_cmp_requeue_value_neq, args->val, val);
LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
args->val, val);
futex_put(f2, NULL);
futex_put(f, NULL);
return (EAGAIN);
}
td->td_retval[0] = futex_requeue(f, nrwake, f2, nrrequeue);
futex_put(f2, NULL);
futex_put(f, NULL);
return (0);
umtxq_unlock(&key);
umtx_key_release(&key2);
umtx_key_release(&key);
return (error);
}
static int
linux_futex_wake(struct thread *td, struct linux_futex_args *args)
{
struct futex *f;
struct umtx_key key;
int error;
f = NULL;
error = futex_get(args->uaddr, NULL, &f, args->flags | FUTEX_DONTCREATE);
if (args->val3 == 0)
return (EINVAL);
error = umtx_key_get(args->uaddr, TYPE_FUTEX, GET_SHARED(args), &key);
if (error != 0)
return (error);
if (f == NULL) {
td->td_retval[0] = 0;
return (error);
}
td->td_retval[0] = futex_wake(f, args->val, args->val3);
futex_put(f, NULL);
umtxq_lock(&key);
td->td_retval[0] = umtxq_signal_mask(&key, args->val, args->val3);
umtxq_unlock(&key);
umtx_key_release(&key);
return (0);
}
static int
linux_futex_wait(struct thread *td, struct linux_futex_args *args)
{
struct waiting_proc *wp;
struct timespec kts;
struct futex *f;
struct umtx_abs_timeout timo;
struct umtx_q *uq;
uint32_t uval;
int error;
uint32_t val;
if (args->ts != NULL) {
if (args->clockrt) {
nanotime(&kts);
timespecsub(args->ts, &kts, args->ts);
} else if (args->op == LINUX_FUTEX_WAIT_BITSET) {
nanouptime(&kts);
timespecsub(args->ts, &kts, args->ts);
}
}
if (args->val3 == 0)
error = EINVAL;
retry:
f = NULL;
error = futex_get(args->uaddr, &wp, &f, args->flags | FUTEX_CREATE_WP);
uq = td->td_umtxq;
error = umtx_key_get(args->uaddr, TYPE_FUTEX, GET_SHARED(args),
&uq->uq_key);
if (error != 0)
return (error);
error = copyin_nofault(args->uaddr, &val, sizeof(val));
if (error != 0) {
futex_put(f, wp);
error = copyin(args->uaddr, &val, sizeof(val));
if (error == 0)
goto retry;
LIN_SDT_PROBE1(futex, linux_futex, copyin_error, error);
LINUX_CTR1(sys_futex, "WAIT copyin failed %d", error);
return (error);
}
if (val != args->val) {
LIN_SDT_PROBE4(futex, linux_futex,
debug_wait_value_neq, args->uaddr, args->val, val,
args->val3);
LINUX_CTR3(sys_futex,
"WAIT uaddr %p val 0x%x != uval 0x%x",
args->uaddr, args->val, val);
futex_put(f, wp);
return (EWOULDBLOCK);
}
if (args->val3 == 0) {
futex_put(f, wp);
return (EINVAL);
}
f->f_bitset = args->val3;
error = futex_sleep(f, wp, args->ts);
if (args->ts != NULL)
linux_umtx_abs_timeout_init(&timo, args);
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
uq->uq_bitset = args->val3;
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
error = fueword32(args->uaddr, &uval);
if (error != 0)
LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
if (error == EWOULDBLOCK)
error = ETIMEDOUT;
error = EFAULT;
else if (uval != args->val)
error = EWOULDBLOCK;
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
if (error == 0) {
error = umtxq_sleep(uq, "futex",
args->ts == NULL ? NULL : &timo);
if ((uq->uq_flags & UQF_UMTXQ) == 0)
error = 0;
else
umtxq_remove(uq);
} else if ((uq->uq_flags & UQF_UMTXQ) != 0) {
umtxq_remove(uq);
}
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
if (error == ERESTART)
error = EINTR;
return (error);
}
static void
linux_umtx_abs_timeout_init(struct umtx_abs_timeout *timo,
struct linux_futex_args *args)
{
int clockid, absolute;
/*
* The FUTEX_CLOCK_REALTIME option bit can be employed only with the
* FUTEX_WAIT_BITSET, FUTEX_WAIT_REQUEUE_PI.
* For FUTEX_WAIT, timeout is interpreted as a relative value, for other
* futex operations timeout is interpreted as an absolute value.
* If FUTEX_CLOCK_REALTIME option bit is set, the Linux kernel measures
* the timeout against the CLOCK_REALTIME clock, otherwise the kernel
* measures the timeout against the CLOCK_MONOTONIC clock.
*/
clockid = args->clockrt ? CLOCK_REALTIME : CLOCK_MONOTONIC;
absolute = args->op == LINUX_FUTEX_WAIT ? false : true;
umtx_abs_timeout_init(timo, clockid, absolute, args->ts);
}
int
linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
{
@ -1149,7 +702,6 @@ handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr,
unsigned int pi)
{
uint32_t uval, nval, mval;
struct futex *f;
int error;
retry:
@ -1169,14 +721,9 @@ handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr,
goto retry;
if (!pi && (uval & FUTEX_WAITERS)) {
error = futex_get(uaddr, NULL, &f,
FUTEX_DONTCREATE | FUTEX_SHARED);
if (error)
error = futex_wake(curthread, uaddr, 1, true);
if (error != 0)
return (error);
if (f != NULL) {
futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
futex_put(f, NULL);
}
}
}

1
sys/compat/linux/linux_futex.h
View File

@ -83,6 +83,7 @@ int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
int futex_wake(struct thread *td, uint32_t *uaddr, int val, bool shared);
void release_futexes(struct thread *,
struct linux_emuldata *);

2
sys/compat/linux/linux_util.c
View File

@ -60,8 +60,6 @@ __FBSDID("$FreeBSD$");
MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures");
MALLOC_DEFINE(M_EPOLL, "lepoll", "Linux events structures");
MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes");
MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futex waiting proc");
FEATURE(linuxulator_v4l, "V4L ioctl wrapper support in the linuxulator");
FEATURE(linuxulator_v4l2, "V4L2 ioctl wrapper support in the linuxulator");

2
sys/compat/linux/linux_util.h
View File

@ -47,8 +47,6 @@
MALLOC_DECLARE(M_LINUX);
MALLOC_DECLARE(M_EPOLL);
MALLOC_DECLARE(M_FUTEX);
MALLOC_DECLARE(M_FUTEX_WP);
extern char linux_emul_path[];
extern int linux_use_emul_path;

5
sys/i386/linux/linux_sysvec.c
View File

@ -37,10 +37,8 @@ __FBSDID("$FreeBSD$");
#include <sys/imgact_aout.h>
#include <sys/imgact_elf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/stddef.h>
#include <sys/signalvar.h>
@ -1128,8 +1126,6 @@ linux_elf_modevent(module_t mod, int type, void *data)
if (error == 0) {
SET_FOREACH(lihp, linux_ioctl_handler_set)
linux_ioctl_register_handler(*lihp);
LIST_INIT(&futex_list);
mtx_init(&futex_mtx, "ftllk", NULL, MTX_DEF);
linux_dev_shm_create();
linux_osd_jail_register();
stclohz = (stathz ? stathz : hz);
@ -1152,7 +1148,6 @@ linux_elf_modevent(module_t mod, int type, void *data)
if (error == 0) {
SET_FOREACH(lihp, linux_ioctl_handler_set)
linux_ioctl_unregister_handler(*lihp);
mtx_destroy(&futex_mtx);
linux_dev_shm_destroy();
linux_osd_jail_deregister();
if (bootverbose)