svn commit: r339774 - head/sys/riscv/riscv

[Ruslan Bukin]

Author: br
Date: Fri Oct 26 12:27:07 2018
New Revision: 339774
URL: https://svnweb.freebsd.org/changeset/base/339774

Log:
  o Add pmap lock around pmap_fault_fixup() to ensure other thread will not
    modify l3 pte after we loaded old value and before we stored new value.
  o Preset A(accessed), D(dirty) bits for kernel mappings.
  
  Reported by:  kib
  Reviewed by:  markj
  Discussed with:       jhb
  Sponsored by: DARPA, AFRL

Modified:
  head/sys/riscv/riscv/pmap.c

Modified: head/sys/riscv/riscv/pmap.c
==============================================================================
--- head/sys/riscv/riscv/pmap.c Fri Oct 26 11:53:20 2018        (r339773)
+++ head/sys/riscv/riscv/pmap.c Fri Oct 26 12:27:07 2018        (r339774)
@@ -2015,16 +2015,21 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_
        pt_entry_t orig_l3;
        pt_entry_t new_l3;
        pt_entry_t *l3;
+       int rv;
 
+       rv = 0;
+
+       PMAP_LOCK(pmap);
+
        l3 = pmap_l3(pmap, va);
        if (l3 == NULL)
-               return (0);
+               goto done;
 
        orig_l3 = pmap_load(l3);
        if ((orig_l3 & PTE_V) == 0 ||
            ((prot & VM_PROT_WRITE) != 0 && (orig_l3 & PTE_W) == 0) ||
            ((prot & VM_PROT_READ) != 0 && (orig_l3 & PTE_R) == 0))
-               return (0);
+               goto done;
 
        new_l3 = orig_l3 | PTE_A;
        if ((prot & VM_PROT_WRITE) != 0)
@@ -2033,7 +2038,8 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_
        if (orig_l3 != new_l3) {
                pmap_load_store(l3, new_l3);
                pmap_invalidate_page(pmap, va);
-               return (1);
+               rv = 1;
+               goto done;
        }
 
        /*      
@@ -2041,7 +2047,10 @@ pmap_fault_fixup(pmap_t pmap, vm_offset_t va, vm_prot_
         * the PTE shouldn't have resulted in a fault.
         */
 
-       return (0);
+done:
+       PMAP_UNLOCK(pmap);
+
+       return (rv);
 }
 
 /*
@@ -2084,6 +2093,8 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, v
                new_l3 |= PTE_W;
        if ((va >> 63) == 0)
                new_l3 |= PTE_U;
+       else
+               new_l3 |= PTE_A | PTE_D;
 
        new_l3 |= (pn << PTE_PPN0_S);
        if ((flags & PMAP_ENTER_WIRED) != 0)
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