Module Name: src
Committed By: christos
Date: Tue Apr 16 23:03:05 UTC 2013
Modified Files:
src/sys/compat/linux/common: linux_futex.c linux_futex.h
Log Message:
Add some more futex gunk and explain why it does not work (yet).
Now skype aborts with a futex timeout, instead of a stack smash leading
to a SEGV.
To generate a diff of this commit:
cvs rdiff -u -r1.28 -r1.29 src/sys/compat/linux/common/linux_futex.c
cvs rdiff -u -r1.6 -r1.7 src/sys/compat/linux/common/linux_futex.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/compat/linux/common/linux_futex.c
diff -u src/sys/compat/linux/common/linux_futex.c:1.28 src/sys/compat/linux/common/linux_futex.c:1.29
--- src/sys/compat/linux/common/linux_futex.c:1.28 Thu Nov 17 23:07:44 2011
+++ src/sys/compat/linux/common/linux_futex.c Tue Apr 16 19:03:05 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_futex.c,v 1.28 2011/11/18 04:07:44 christos Exp $ */
+/* $NetBSD: linux_futex.c,v 1.29 2013/04/16 23:03:05 christos Exp $ */
/*-
* Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
@@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.28 2011/11/18 04:07:44 christos Exp $");
+__KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.29 2013/04/16 23:03:05 christos Exp $");
#include <sys/param.h>
#include <sys/time.h>
@@ -67,6 +67,7 @@ struct waiting_proc {
struct futex {
void *f_uaddr;
int f_refcount;
+ uint32_t f_bitset;
LIST_ENTRY(futex) f_list;
TAILQ_HEAD(, waiting_proc) f_waiting_proc;
TAILQ_HEAD(, waiting_proc) f_requeue_proc;
@@ -105,7 +106,7 @@ linux_futex_fini(void)
static struct waiting_proc *futex_wp_alloc(void);
static void futex_wp_free(struct waiting_proc *);
-static struct futex *futex_get(void *);
+static struct futex *futex_get(void *, uint32_t);
static void futex_ref(struct futex *);
static void futex_put(struct futex *);
static int futex_sleep(struct futex **, lwp_t *, int, struct waiting_proc *);
@@ -127,7 +128,7 @@ linux_sys_futex(struct lwp *l, const str
struct timespec ts = { 0, 0 };
int error;
- if ((SCARG(uap, op) & ~LINUX_FUTEX_PRIVATE_FLAG) == LINUX_FUTEX_WAIT &&
+ if ((SCARG(uap, op) & LINUX_FUTEX_CMD_MASK) == LINUX_FUTEX_WAIT &&
SCARG(uap, timeout) != NULL) {
if ((error = copyin(SCARG(uap, timeout),
<s, sizeof(lts))) != 0) {
@@ -149,15 +150,31 @@ linux_do_futex(struct lwp *l, const stru
syscallarg(int *) uaddr2;
syscallarg(int) val3;
} */
- int val;
+ int val, val3;
int ret;
int error = 0;
struct futex *f;
struct futex *newf;
- int timeout_hz;
+ int tout;
struct futex *f2;
struct waiting_proc *wp;
- int op_ret;
+ int op_ret, cmd;
+ clockid_t clk;
+
+ cmd = SCARG(uap, op) & LINUX_FUTEX_CMD_MASK;
+ val3 = SCARG(uap, val3);
+
+ if (SCARG(uap, op) & LINUX_FUTEX_CLOCK_REALTIME) {
+ switch (cmd) {
+ case LINUX_FUTEX_WAIT_BITSET:
+ case LINUX_FUTEX_WAIT:
+ clk = CLOCK_REALTIME;
+ break;
+ default:
+ return ENOSYS;
+ }
+ } else
+ clk = CLOCK_MONOTONIC;
/*
* Our implementation provides only private futexes. Most of the apps
@@ -165,11 +182,33 @@ linux_do_futex(struct lwp *l, const stru
* all futexes as private by clearing the FUTEX_PRIVATE_FLAG. It works
* in most cases (ie. when futexes are not shared on file descriptor
* or between different processes).
+ *
+ * Note that we don't handle bitsets at all at the moment. We need
+ * to move from refcounting uaddr's to handling multiple futex entries
+ * pointing to the same uaddr, but having possibly different bitmask.
+ * Perhaps move to an implementation where each uaddr has a list of
+ * futexes.
*/
- switch (SCARG(uap, op) & ~LINUX_FUTEX_PRIVATE_FLAG) {
+ switch (cmd) {
case LINUX_FUTEX_WAIT:
+ val3 = FUTEX_BITSET_MATCH_ANY;
+ /*FALLTHROUGH*/
+ case LINUX_FUTEX_WAIT_BITSET:
+ if ((error = ts2timo(clk, 0, ts, &tout, NULL)) != 0) {
+ /*
+ * If the user process requests a non null timeout,
+ * make sure we do not turn it into an infinite
+ * timeout because tout is 0.
+ *
+ * We use a minimal timeout of 1/hz. Maybe it would make
+ * sense to just return ETIMEDOUT without sleeping.
+ */
+ if (error == ETIMEDOUT && SCARG(uap, timeout) != NULL)
+ tout = 1;
+ else
+ return error;
+ }
FUTEX_SYSTEM_LOCK;
-
if ((error = copyin(SCARG(uap, uaddr),
&val, sizeof(val))) != 0) {
FUTEX_SYSTEM_UNLOCK;
@@ -187,27 +226,11 @@ linux_do_futex(struct lwp *l, const stru
SCARG(uap, uaddr), val, (long long)ts->tv_sec,
ts->tv_nsec));
- if ((error = itimespecfix(ts)) != 0) {
- FUTEX_SYSTEM_UNLOCK;
- return error;
- }
- timeout_hz = tstohz(ts);
-
- /*
- * If the user process requests a non null timeout,
- * make sure we do not turn it into an infinite
- * timeout because timeout_hz is 0.
- *
- * We use a minimal timeout of 1/hz. Maybe it would make
- * sense to just return ETIMEDOUT without sleeping.
- */
- if (SCARG(uap, timeout) != NULL && timeout_hz == 0)
- timeout_hz = 1;
wp = futex_wp_alloc();
FUTEX_LOCK;
- f = futex_get(SCARG(uap, uaddr));
- ret = futex_sleep(&f, l, timeout_hz, wp);
+ f = futex_get(SCARG(uap, uaddr), val3);
+ ret = futex_sleep(&f, l, tout, wp);
futex_put(f);
FUTEX_UNLOCK;
futex_wp_free(wp);
@@ -238,6 +261,9 @@ linux_do_futex(struct lwp *l, const stru
break;
case LINUX_FUTEX_WAKE:
+ val = FUTEX_BITSET_MATCH_ANY;
+ /*FALLTHROUGH*/
+ case LINUX_FUTEX_WAKE_BITSET:
/*
* XXX: Linux is able cope with different addresses
* corresponding to the same mapped memory in the sleeping
@@ -249,7 +275,7 @@ linux_do_futex(struct lwp *l, const stru
FUTEX_SYSTEM_LOCK;
FUTEX_LOCK;
- f = futex_get(SCARG(uap, uaddr));
+ f = futex_get(SCARG(uap, uaddr), val3);
*retval = futex_wake(f, SCARG(uap, val), NULL, 0);
futex_put(f);
FUTEX_UNLOCK;
@@ -266,7 +292,7 @@ linux_do_futex(struct lwp *l, const stru
return error;
}
- if (val != SCARG(uap, val3)) {
+ if (val != val3) {
FUTEX_SYSTEM_UNLOCK;
return EAGAIN;
}
@@ -278,8 +304,8 @@ linux_do_futex(struct lwp *l, const stru
(int)(unsigned long)SCARG(uap, timeout)));
FUTEX_LOCK;
- f = futex_get(SCARG(uap, uaddr));
- newf = futex_get(SCARG(uap, uaddr2));
+ f = futex_get(SCARG(uap, uaddr), val3);
+ newf = futex_get(SCARG(uap, uaddr2), val3);
*retval = futex_wake(f, SCARG(uap, val), newf,
(int)(unsigned long)SCARG(uap, timeout));
futex_put(f);
@@ -299,8 +325,8 @@ linux_do_futex(struct lwp *l, const stru
(int)(unsigned long)SCARG(uap, timeout)));
FUTEX_LOCK;
- f = futex_get(SCARG(uap, uaddr));
- newf = futex_get(SCARG(uap, uaddr2));
+ f = futex_get(SCARG(uap, uaddr), val3);
+ newf = futex_get(SCARG(uap, uaddr2), val3);
*retval = futex_wake(f, SCARG(uap, val), newf,
(int)(unsigned long)SCARG(uap, timeout));
futex_put(f);
@@ -311,8 +337,7 @@ linux_do_futex(struct lwp *l, const stru
break;
case LINUX_FUTEX_FD:
- FUTEXPRINTF(("linux_sys_futex: unimplemented op %d\n",
- SCARG(uap, op)));
+ FUTEXPRINTF(("%s: unimplemented op %d\n", __func__, cmd));
return ENOSYS;
case LINUX_FUTEX_WAKE_OP:
FUTEX_SYSTEM_LOCK;
@@ -320,20 +345,20 @@ linux_do_futex(struct lwp *l, const stru
FUTEXPRINTF(("FUTEX_WAKE_OP %d.%d: uaddr = %p, op = %d, "
"val = %d, uaddr2 = %p, val2 = %d\n",
l->l_proc->p_pid, l->l_lid,
- SCARG(uap, uaddr), SCARG(uap, op), SCARG(uap, val),
+ SCARG(uap, uaddr), cmd, SCARG(uap, val),
SCARG(uap, uaddr2),
(int)(unsigned long)SCARG(uap, timeout)));
FUTEX_LOCK;
- f = futex_get(SCARG(uap, uaddr));
- f2 = futex_get(SCARG(uap, uaddr2));
+ f = futex_get(SCARG(uap, uaddr), val3);
+ f2 = futex_get(SCARG(uap, uaddr2), val3);
FUTEX_UNLOCK;
/*
* This function returns positive number as results and
* negative as errors
*/
- op_ret = futex_atomic_op(l, SCARG(uap, val3), SCARG(uap, uaddr2));
+ op_ret = futex_atomic_op(l, val3, SCARG(uap, uaddr2));
FUTEX_LOCK;
if (op_ret < 0) {
futex_put(f);
@@ -361,8 +386,7 @@ linux_do_futex(struct lwp *l, const stru
*retval = ret;
break;
default:
- FUTEXPRINTF(("linux_sys_futex: unknown op %d\n",
- SCARG(uap, op)));
+ FUTEXPRINTF(("%s: unknown op %d\n", __func__, cmd));
return ENOSYS;
}
return 0;
@@ -387,7 +411,7 @@ futex_wp_free(struct waiting_proc *wp)
}
static struct futex *
-futex_get(void *uaddr)
+futex_get(void *uaddr, uint32_t bitset)
{
struct futex *f;
@@ -403,6 +427,7 @@ futex_get(void *uaddr)
/* Not found, create it */
f = kmem_zalloc(sizeof(*f), KM_SLEEP);
f->f_uaddr = uaddr;
+ f->f_bitset = bitset;
f->f_refcount = 1;
TAILQ_INIT(&f->f_waiting_proc);
TAILQ_INIT(&f->f_requeue_proc);
@@ -483,8 +508,8 @@ futex_wake(struct futex *f, int n, struc
TAILQ_FOREACH(wp, &f->f_waiting_proc, wp_list) {
KASSERT(wp->wp_new_futex == NULL);
- FUTEXPRINTF(("futex_wake: signal f %p l %p ref %d\n",
- f, wp->wp_l, f->f_refcount));
+ FUTEXPRINTF(("%s: signal f %p l %p ref %d\n", __func__,
+ f, wp->wp_l, f->f_refcount));
cv_signal(&wp->wp_futex_cv);
if (count <= n) {
count++;
@@ -496,8 +521,8 @@ futex_wake(struct futex *f, int n, struc
futex_ref(newf);
wp->wp_new_futex = newf;
TAILQ_INSERT_TAIL(&newf->f_requeue_proc, wp, wp_rqlist);
- FUTEXPRINTF(("futex_wake: requeue newf %p l %p ref %d\n",
- newf, wp->wp_l, newf->f_refcount));
+ FUTEXPRINTF(("%s: requeue newf %p l %p ref %d\n",
+ __func__, newf, wp->wp_l, newf->f_refcount));
if (count - n >= n2)
goto out;
}
@@ -515,8 +540,8 @@ futex_wake(struct futex *f, int n, struc
TAILQ_FOREACH_SAFE(wp, &f->f_requeue_proc, wp_rqlist, wpnext) {
KASSERT(wp->wp_new_futex == f);
- FUTEXPRINTF(("futex_wake: unrequeue f %p l %p ref %d\n",
- f, wp->wp_l, f->f_refcount));
+ FUTEXPRINTF(("%s: unrequeue f %p l %p ref %d\n", __func__,
+ f, wp->wp_l, f->f_refcount));
wp->wp_new_futex = NULL;
TAILQ_REMOVE(&f->f_requeue_proc, wp, wp_rqlist);
futex_put(f);
@@ -531,8 +556,8 @@ futex_wake(struct futex *f, int n, struc
futex_ref(newf);
wp->wp_new_futex = newf;
TAILQ_INSERT_TAIL(&newf->f_requeue_proc, wp, wp_rqlist);
- FUTEXPRINTF(("futex_wake: rerequeue newf %p l %p ref %d\n",
- newf, wp->wp_l, newf->f_refcount));
+ FUTEXPRINTF(("%s: rerequeue newf %p l %p ref %d\n",
+ __func__, newf, wp->wp_l, newf->f_refcount));
if (count - n >= n2)
break;
}
@@ -701,7 +726,7 @@ retry:
if (!pi && (uval & FUTEX_WAITERS)) {
FUTEX_LOCK;
- f = futex_get(uaddr);
+ f = futex_get(uaddr, FUTEX_BITSET_MATCH_ANY);
futex_wake(f, 1, NULL, 0);
FUTEX_UNLOCK;
}
Index: src/sys/compat/linux/common/linux_futex.h
diff -u src/sys/compat/linux/common/linux_futex.h:1.6 src/sys/compat/linux/common/linux_futex.h:1.7
--- src/sys/compat/linux/common/linux_futex.h:1.6 Thu Jan 10 21:49:09 2013
+++ src/sys/compat/linux/common/linux_futex.h Tue Apr 16 19:03:05 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_futex.h,v 1.6 2013/01/11 02:49:09 christos Exp $ */
+/* $NetBSD: linux_futex.h,v 1.7 2013/04/16 23:03:05 christos Exp $ */
/*-
* Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
@@ -50,6 +50,8 @@
#define LINUX_FUTEX_PRIVATE_FLAG 128
#define LINUX_FUTEX_CLOCK_REALTIME 256
+#define LINUX_FUTEX_CMD_MASK \
+ (~(LINUX_FUTEX_PRIVATE_FLAG|LINUX_FUTEX_CLOCK_REALTIME))
#define FUTEX_OP_SET 0
#define FUTEX_OP_ADD 1
@@ -79,6 +81,8 @@ struct linux_robust_list_head {
#define FUTEX_OWNER_DIED 0x40000000
#define FUTEX_TID_MASK 0x3fffffff
+#define FUTEX_BITSET_MATCH_ANY 0xffffffff
+
void release_futexes(struct lwp *);
struct linux_sys_futex_args;
int linux_do_futex(struct lwp *, const struct linux_sys_futex_args *,
