Author: cperciva
Date: Fri Dec 31 17:40:30 2010
New Revision: 216845
URL: http://svn.freebsd.org/changeset/base/216845
Log:
Make i386_set_ldt work on i386/XEN, step 3/5.
Synchronize reality with comment: The user_ldt_alloc function is supposed to
return with dt_lock held. Due to broken locking in i386/xen/pmap.c, we drop
dt_lock during the call to pmap_map_readonly and then pick it up again; this
can be removed once the Xen pmap locking is fixed.
MFC after: 3 days
Modified:
head/sys/i386/i386/sys_machdep.c
Modified: head/sys/i386/i386/sys_machdep.c
==============================================================================
--- head/sys/i386/i386/sys_machdep.c Fri Dec 31 17:39:58 2010
(r216844)
+++ head/sys/i386/i386/sys_machdep.c Fri Dec 31 17:40:30 2010
(r216845)
@@ -450,6 +450,7 @@ user_ldt_alloc(struct mdproc *mdp, int l
new_ldt->ldt_refcnt = 1;
new_ldt->ldt_active = 0;
+ mtx_lock_spin(&dt_lock);
if ((pldt = mdp->md_ldt)) {
if (len > pldt->ldt_len)
len = pldt->ldt_len;
@@ -458,8 +459,10 @@ user_ldt_alloc(struct mdproc *mdp, int l
} else {
bcopy(ldt, new_ldt->ldt_base, PAGE_SIZE);
}
+ mtx_unlock_spin(&dt_lock); /* XXX kill once pmap locking fixed. */
pmap_map_readonly(kernel_pmap, (vm_offset_t)new_ldt->ldt_base,
new_ldt->ldt_len*sizeof(union descriptor));
+ mtx_lock_spin(&dt_lock); /* XXX kill once pmap locking fixed. */
return (new_ldt);
}
#else
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