git: 0dc38e33031b - main - linux(4): Reimplement futexes using umtx.
Dmitry Chagin
dchagin at FreeBSD.org
Thu Jul 29 09:46:12 UTC 2021
The branch main has been updated by dchagin:
URL: https://cgit.FreeBSD.org/src/commit/?id=0dc38e33031b353468888fe25a6f8ba1f910dd26
commit 0dc38e33031b353468888fe25a6f8ba1f910dd26
Author: Dmitry Chagin <dchagin at FreeBSD.org>
AuthorDate: 2021-07-29 09:43:48 +0000
Commit: Dmitry Chagin <dchagin at FreeBSD.org>
CommitDate: 2021-07-29 09:43:48 +0000
linux(4): Reimplement futexes using umtx.
Differential Revision: https://reviews.freebsd.org/D31236
MFC after: 2 weeks
---
sys/compat/linux/linux.c | 3 -
sys/compat/linux/linux.h | 3 -
sys/compat/linux/linux_common.c | 4 -
sys/compat/linux/linux_fork.c | 9 +-
sys/compat/linux/linux_futex.c | 719 ++++++++--------------------------------
sys/compat/linux/linux_futex.h | 1 +
sys/compat/linux/linux_util.c | 2 -
sys/compat/linux/linux_util.h | 2 -
sys/i386/linux/linux_sysvec.c | 5 -
9 files changed, 135 insertions(+), 613 deletions(-)
diff --git a/sys/compat/linux/linux.c b/sys/compat/linux/linux.c
index e72e5cbc7bfc..8cc678e1ec7d 100644
--- a/sys/compat/linux/linux.c
+++ b/sys/compat/linux/linux.c
@@ -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] = {
diff --git a/sys/compat/linux/linux.h b/sys/compat/linux/linux.h
index 730aece66a6a..cd123622d14a 100644
--- a/sys/compat/linux/linux.h
+++ b/sys/compat/linux/linux.h
@@ -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);
diff --git a/sys/compat/linux/linux_common.c b/sys/compat/linux/linux_common.c
index 4d81470649de..0009d9d26164 100644
--- a/sys/compat/linux/linux_common.c
+++ b/sys/compat/linux/linux_common.c
@@ -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);
diff --git a/sys/compat/linux/linux_fork.c b/sys/compat/linux/linux_fork.c
index 8230d5b4108b..ff2d5dcfc957 100644
--- a/sys/compat/linux/linux_fork.c
+++ b/sys/compat/linux/linux_fork.c
@@ -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
diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index 547d52c8ca4a..df6c7cdbf74a 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -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;
-};
-
-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 GET_SHARED(a) (a->flags & FUTEX_SHARED) ? AUTO_SHARE : THREAD_SHARE
-#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)
-{
-
- 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);
- }
-
- 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)
+int
+futex_wake(struct thread *td, uint32_t *uaddr, int val, bool shared)
{
- struct waiting_proc *wp, *wpt;
- int count = 0;
+ struct linux_futex_args args;
- if (bitset == 0)
- return (EINVAL);
+ 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;
- 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);
+ error = ENOSYS;
+ else
+ error = EFAULT;
}
-
- ret = futex_wake(f, args->val, args->val3);
-
+ umtxq_lock(&key);
+ umtxq_unbusy(&key);
+ if (error != 0)
+ goto out;
+ ret = umtxq_signal_mask(&key, 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);
+ umtxq_lock(&key2);
+ count = umtxq_count(&key2);
+ if (count > 0)
+ ret += umtxq_signal_mask(&key2, nrwake, args->val3);
else
- op_ret += futex_wake(f, nrwake, args->val3);
- ret += op_ret;
+ 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);
- if (error != 0) {
- futex_put(f, NULL);
- return (error);
- }
- futex_lock(f);
- futex_lock(f2);
- error = copyin_nofault(args->uaddr, &val, sizeof(val));
+ error = umtx_key_get(args->uaddr2, TYPE_FUTEX, GET_SHARED(args), &key2);
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);
+ umtx_key_release(&key);
return (error);
}
- 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_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);
+ }
+ 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 (error != 0)
- return (error);
+ if (args->val3 == 0)
+ return (EINVAL);
- if (f == NULL) {
- td->td_retval[0] = 0;
+ error = umtx_key_get(args->uaddr, TYPE_FUTEX, GET_SHARED(args), &key);
+ if (error != 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);
- }
- }
-retry:
- f = NULL;
- error = futex_get(args->uaddr, &wp, &f, args->flags | FUTEX_CREATE_WP);
- if (error != 0)
- return (error);
+ if (args->val3 == 0)
+ error = EINVAL;
- 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);
+ uq = td->td_umtxq;
+ error = umtx_key_get(args->uaddr, TYPE_FUTEX, GET_SHARED(args),
+ &uq->uq_key);
+ if (error != 0)
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 @@ retry:
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);
- }
}
}
diff --git a/sys/compat/linux/linux_futex.h b/sys/compat/linux/linux_futex.h
index 6ea873d98411..4255cbdc7363 100644
--- a/sys/compat/linux/linux_futex.h
+++ b/sys/compat/linux/linux_futex.h
@@ -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 *,
*** 60 LINES SKIPPED ***
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