Author: jhibbits
Date: Sat Feb 22 01:31:06 2020
New Revision: 358234
URL: https://svnweb.freebsd.org/changeset/base/358234

Log:
  powerpc/booke: Fix handling of pvh_global_lock and pmap lock
  
  ptbl_alloc() is expected to return with the pvh_global_lock and pmap
  lock held.  However, it will return with them unlocked if nosleep is
  specified.
  
  Along with this, fix lock ordering of pvh_global_lock with respect to
  the pmap lock in other places.
  
  Differential Revision: https://reviews.freebsd.org/D23692

Modified:
  head/sys/powerpc/booke/pmap.c

Modified: head/sys/powerpc/booke/pmap.c
==============================================================================
--- head/sys/powerpc/booke/pmap.c       Fri Feb 21 22:44:22 2020        
(r358233)
+++ head/sys/powerpc/booke/pmap.c       Sat Feb 22 01:31:06 2020        
(r358234)
@@ -705,11 +705,10 @@ ptbl_alloc(mmu_t mmu, pmap_t pmap, pte_t ** pdir, unsi
 
        req = VM_ALLOC_NOOBJ | VM_ALLOC_WIRED;
        while ((m = vm_page_alloc(NULL, pdir_idx, req)) == NULL) {
+               if (nosleep)
+                       return (NULL);
                PMAP_UNLOCK(pmap);
                rw_wunlock(&pvh_global_lock);
-               if (nosleep) {
-                       return (NULL);
-               }
                vm_wait(NULL);
                rw_wlock(&pvh_global_lock);
                PMAP_LOCK(pmap);
@@ -905,8 +904,6 @@ ptbl_alloc(mmu_t mmu, pmap_t pmap, unsigned int pdir_i
                pidx = (PTBL_PAGES * pdir_idx) + i;
                while ((m = vm_page_alloc(NULL, pidx,
                    VM_ALLOC_NOOBJ | VM_ALLOC_WIRED)) == NULL) {
-                       PMAP_UNLOCK(pmap);
-                       rw_wunlock(&pvh_global_lock);
                        if (nosleep) {
                                ptbl_free_pmap_ptbl(pmap, ptbl);
                                for (j = 0; j < i; j++)
@@ -914,6 +911,8 @@ ptbl_alloc(mmu_t mmu, pmap_t pmap, unsigned int pdir_i
                                vm_wire_sub(i);
                                return (NULL);
                        }
+                       PMAP_UNLOCK(pmap);
+                       rw_wunlock(&pvh_global_lock);
                        vm_wait(NULL);
                        rw_wlock(&pvh_global_lock);
                        PMAP_LOCK(pmap);
@@ -2481,8 +2480,8 @@ mmu_booke_enter_object(mmu_t mmu, pmap_t pmap, vm_offs
                    PMAP_ENTER_NOSLEEP | PMAP_ENTER_QUICK_LOCKED, 0);
                m = TAILQ_NEXT(m, listq);
        }
-       rw_wunlock(&pvh_global_lock);
        PMAP_UNLOCK(pmap);
+       rw_wunlock(&pvh_global_lock);
 }
 
 static void
@@ -2495,8 +2494,8 @@ mmu_booke_enter_quick(mmu_t mmu, pmap_t pmap, vm_offse
        mmu_booke_enter_locked(mmu, pmap, va, m,
            prot & (VM_PROT_READ | VM_PROT_EXECUTE), PMAP_ENTER_NOSLEEP |
            PMAP_ENTER_QUICK_LOCKED, 0);
-       rw_wunlock(&pvh_global_lock);
        PMAP_UNLOCK(pmap);
+       rw_wunlock(&pvh_global_lock);
 }
 
 /*
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