Module Name: src
Committed By: maxv
Date: Sat Jun 1 08:12:26 UTC 2019
Modified Files:
src/sys/arch/x86/x86: pmap.c
Log Message:
Fix two bugs in pmap_write_protect():
* The mask should be ~PAGE_MASK, not PTE_FRAME. PTE_FRAME eliminates the
higher bits, and that's not wanted.
* The computation of tva is incorrect: if the VA is in kernel space we
must take the canonical hole into account, and here we were not.
We've had these bugs basically forever. It meant that uvm_km_protect()
would never flush the correct VA, and a stale TLB entry would persist.
Fixes PR/54257. Since I added PCID support we execute invpcid in invlpg(),
and invpcid triggers a #GP if the address is non canonical, contrary to
invlpg. The wrong computation of the VA during a modload happened to hit
the canonical hole.
To generate a diff of this commit:
cvs rdiff -u -r1.333 -r1.334 src/sys/arch/x86/x86/pmap.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/x86/x86/pmap.c
diff -u src/sys/arch/x86/x86/pmap.c:1.333 src/sys/arch/x86/x86/pmap.c:1.334
--- src/sys/arch/x86/x86/pmap.c:1.333 Mon May 27 18:36:37 2019
+++ src/sys/arch/x86/x86/pmap.c Sat Jun 1 08:12:26 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.333 2019/05/27 18:36:37 maxv Exp $ */
+/* $NetBSD: pmap.c,v 1.334 2019/06/01 08:12:26 maxv Exp $ */
/*
* Copyright (c) 2008, 2010, 2016, 2017 The NetBSD Foundation, Inc.
@@ -130,7 +130,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.333 2019/05/27 18:36:37 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.334 2019/06/01 08:12:26 maxv Exp $");
#include "opt_user_ldt.h"
#include "opt_lockdebug.h"
@@ -4017,7 +4017,7 @@ pmap_write_protect(struct pmap *pmap, va
pt_entry_t * const *pdes;
struct pmap *pmap2;
vaddr_t blockend, va;
- int lvl;
+ int lvl, i;
KASSERT(curlwp->l_md.md_gc_pmap != pmap);
@@ -4034,8 +4034,8 @@ pmap_write_protect(struct pmap *pmap, va
if (!(prot & VM_PROT_EXECUTE))
bit_put = pmap_pg_nx;
- sva &= PTE_FRAME;
- eva &= PTE_FRAME;
+ sva &= ~PAGE_MASK;
+ eva &= ~PAGE_MASK;
/* Acquire pmap. */
kpreempt_disable();
@@ -4058,7 +4058,7 @@ pmap_write_protect(struct pmap *pmap, va
spte = &ptes[pl1_i(va)];
epte = &ptes[pl1_i(blockend)];
- for (/* */; spte < epte; spte++) {
+ for (i = 0; spte < epte; spte++, i++) {
pt_entry_t opte, npte;
do {
@@ -4070,7 +4070,7 @@ pmap_write_protect(struct pmap *pmap, va
} while (pmap_pte_cas(spte, opte, npte) != opte);
if ((opte & PTE_D) != 0) {
- vaddr_t tva = x86_ptob(spte - ptes);
+ vaddr_t tva = va + x86_ptob(i);
pmap_tlb_shootdown(pmap, tva, opte,
TLBSHOOT_WRITE_PROTECT);
}
