Date: Fri, 31 Dec 2010 17:40:31 +0000 (UTC) From: Colin Percival <cperciva@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r216845 - head/sys/i386/i386 Message-ID: <201012311740.oBVHeV1s083581@svn.freebsd.org>
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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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