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Date:      Fri, 11 Jan 2019 02:08:07 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org
Subject:   svn commit: r342926 - stable/12/sys/i386/include
Message-ID:  <201901110208.x0B287sB010970@repo.freebsd.org>
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Author: kib
Date: Fri Jan 11 02:08:06 2019
New Revision: 342926
URL: https://svnweb.freebsd.org/changeset/base/342926

Log:
  MFC r342769, r342775:
  i386: Use atomic 64bit load to read PDE value from PAE pagetables in
  pmap_kextract().

Modified:
  stable/12/sys/i386/include/pmap.h
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/i386/include/pmap.h
==============================================================================
--- stable/12/sys/i386/include/pmap.h	Fri Jan 11 01:54:15 2019	(r342925)
+++ stable/12/sys/i386/include/pmap.h	Fri Jan 11 02:08:06 2019	(r342926)
@@ -194,6 +194,8 @@ typedef uint32_t pt_entry_t;
  * Address of current address space page table maps and directories.
  */
 #ifdef _KERNEL
+#include <machine/atomic.h>
+
 extern pt_entry_t PTmap[];
 extern pd_entry_t PTD[];
 extern pd_entry_t PTDpde[];
@@ -234,6 +236,32 @@ extern pd_entry_t *IdlePTD;	/* physical address of "Id
  */
 extern pt_entry_t *KPTmap;
 
+#if (defined(PAE) || defined(PAE_TABLES))
+
+#define	pde_cmpset(pdep, old, new)	atomic_cmpset_64_i586(pdep, old, new)
+#define	pte_load_store(ptep, pte)	atomic_swap_64_i586(ptep, pte)
+#define	pte_load_clear(ptep)		atomic_swap_64_i586(ptep, 0)
+#define	pte_store(ptep, pte)		atomic_store_rel_64_i586(ptep, pte)
+#define	pte_load(ptep)			atomic_load_acq_64_i586(ptep)
+
+extern pt_entry_t pg_nx;
+
+#else /* !(PAE || PAE_TABLES) */
+
+#define	pde_cmpset(pdep, old, new)	atomic_cmpset_int(pdep, old, new)
+#define	pte_load_store(ptep, pte)	atomic_swap_int(ptep, pte)
+#define	pte_load_clear(ptep)		atomic_swap_int(ptep, 0)
+#define	pte_store(ptep, pte) do { \
+	*(u_int *)(ptep) = (u_int)(pte); \
+} while (0)
+#define	pte_load(ptep)			atomic_load_acq_int(ptep)
+
+#endif /* !(PAE || PAE_TABLES) */
+
+#define	pte_clear(ptep)			pte_store(ptep, 0)
+
+#define	pde_store(pdep, pde)		pte_store(pdep, pde)
+
 /*
  * Extract from the kernel page table the physical address that is mapped by
  * the given virtual address "va".
@@ -245,7 +273,7 @@ pmap_kextract(vm_offset_t va)
 {
 	vm_paddr_t pa;
 
-	if ((pa = PTD[va >> PDRSHIFT]) & PG_PS) {
+	if ((pa = pte_load(&PTD[va >> PDRSHIFT])) & PG_PS) {
 		pa = (pa & PG_PS_FRAME) | (va & PDRMASK);
 	} else {
 		/*
@@ -260,30 +288,6 @@ pmap_kextract(vm_offset_t va)
 	}
 	return (pa);
 }
-
-#if (defined(PAE) || defined(PAE_TABLES))
-
-#define	pde_cmpset(pdep, old, new)	atomic_cmpset_64_i586(pdep, old, new)
-#define	pte_load_store(ptep, pte)	atomic_swap_64_i586(ptep, pte)
-#define	pte_load_clear(ptep)		atomic_swap_64_i586(ptep, 0)
-#define	pte_store(ptep, pte)		atomic_store_rel_64_i586(ptep, pte)
-
-extern pt_entry_t pg_nx;
-
-#else /* !(PAE || PAE_TABLES) */
-
-#define	pde_cmpset(pdep, old, new)	atomic_cmpset_int(pdep, old, new)
-#define	pte_load_store(ptep, pte)	atomic_swap_int(ptep, pte)
-#define	pte_load_clear(ptep)		atomic_swap_int(ptep, 0)
-#define	pte_store(ptep, pte) do { \
-	*(u_int *)(ptep) = (u_int)(pte); \
-} while (0)
-
-#endif /* !(PAE || PAE_TABLES) */
-
-#define	pte_clear(ptep)			pte_store(ptep, 0)
-
-#define	pde_store(pdep, pde)		pte_store(pdep, pde)
 
 #endif /* _KERNEL */

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