git: ec21f85ab5f0 - main - riscv: Handle invalid L2 entries in pmap_extract()

[Mark Johnston]

The branch main has been updated by markj:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=ec21f85ab5f03a803884cc7bafa88621c613f4ca

commit ec21f85ab5f03a803884cc7bafa88621c613f4ca
Author:     Mark Johnston <ma...@freebsd.org>
AuthorDate: 2022-09-29 17:07:26 +0000
Commit:     Mark Johnston <ma...@freebsd.org>
CommitDate: 2022-09-29 17:11:26 +0000

    riscv: Handle invalid L2 entries in pmap_extract()
    
    While here, eliminate a single-use local variable.
    
    PR:             266103
    Reviewed by:    mhorne
    MFC after:      2 weeks
    Differential Revision:  https://reviews.freebsd.org/D36395
---
 sys/riscv/riscv/pmap.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/sys/riscv/riscv/pmap.c b/sys/riscv/riscv/pmap.c
index 6aec89faf860..ddbeb9039c51 100644
--- a/sys/riscv/riscv/pmap.c
+++ b/sys/riscv/riscv/pmap.c
@@ -903,27 +903,25 @@ vm_paddr_t
 pmap_extract(pmap_t pmap, vm_offset_t va)
 {
        pd_entry_t *l2p, l2;
-       pt_entry_t *l3p, l3;
+       pt_entry_t *l3p;
        vm_paddr_t pa;
 
        pa = 0;
-       PMAP_LOCK(pmap);
+
        /*
-        * Start with the l2 tabel. We are unable to allocate
-        * pages in the l1 table.
+        * Start with an L2 lookup, L1 superpages are currently not implemented.
         */
+       PMAP_LOCK(pmap);
        l2p = pmap_l2(pmap, va);
-       if (l2p != NULL) {
-               l2 = pmap_load(l2p);
-               if ((l2 & PTE_RX) == 0) {
+       if (l2p != NULL && ((l2 = pmap_load(l2p)) & PTE_V) != 0) {
+               if ((l2 & PTE_RWX) == 0) {
                        l3p = pmap_l2_to_l3(l2p, va);
                        if (l3p != NULL) {
-                               l3 = pmap_load(l3p);
-                               pa = PTE_TO_PHYS(l3);
+                               pa = PTE_TO_PHYS(pmap_load(l3p));
                                pa |= (va & L3_OFFSET);
                        }
                } else {
-                       /* L2 is superpages */
+                       /* L2 is a superpage mapping. */
                        pa = L2PTE_TO_PHYS(l2);
                        pa |= (va & L2_OFFSET);
                }