From de187b8df23bc3a12184e35dd1f2bdee99a69d2c Mon Sep 17 00:00:00 2001 From: Colin Percival Date: Fri, 31 Dec 2010 17:40:30 +0000 Subject: [PATCH] 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 --- sys/i386/i386/sys_machdep.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/sys/i386/i386/sys_machdep.c b/sys/i386/i386/sys_machdep.c index 2e7abdde25a..4bcf91ddac9 100644 --- a/sys/i386/i386/sys_machdep.c +++ b/sys/i386/i386/sys_machdep.c @@ -450,6 +450,7 @@ user_ldt_alloc(struct mdproc *mdp, int len) 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 len) } 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