Module Name: src
Committed By: maxv
Date: Fri Jan 6 08:32:26 UTC 2017
Modified Files:
src/sys/arch/xen/x86: x86_xpmap.c
Log Message:
Remove a few #if 0s, and explain what we are doing on PAE: the last two PAs
are entered in reversed order.
To generate a diff of this commit:
cvs rdiff -u -r1.68 -r1.69 src/sys/arch/xen/x86/x86_xpmap.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/xen/x86/x86_xpmap.c
diff -u src/sys/arch/xen/x86/x86_xpmap.c:1.68 src/sys/arch/xen/x86/x86_xpmap.c:1.69
--- src/sys/arch/xen/x86/x86_xpmap.c:1.68 Fri Dec 16 19:52:22 2016
+++ src/sys/arch/xen/x86/x86_xpmap.c Fri Jan 6 08:32:26 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: x86_xpmap.c,v 1.68 2016/12/16 19:52:22 maxv Exp $ */
+/* $NetBSD: x86_xpmap.c,v 1.69 2017/01/06 08:32:26 maxv Exp $ */
/*
* Copyright (c) 2006 Mathieu Ropert <[email protected]>
@@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: x86_xpmap.c,v 1.68 2016/12/16 19:52:22 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: x86_xpmap.c,v 1.69 2017/01/06 08:32:26 maxv Exp $");
#include "opt_xen.h"
#include "opt_ddb.h"
@@ -664,7 +664,7 @@ xen_locore(void)
count++;
}
-#ifndef __x86_64__
+#ifdef i386
/*
* One more L2 page: we'll allocate several pages after kva_start
* in pmap_bootstrap() before pmap_growkernel(), which have not been
@@ -832,21 +832,24 @@ xen_bootstrap_tables(vaddr_t old_pgd, va
pdtpe[pl3_pi(KERNTEXTOFF)] =
xpmap_ptom_masked(addr) | PG_k | PG_V | PG_RW;
#elif defined(PAE)
- /* Our PAE-style level 2: 5 contigous pages (4 L2 + 1 shadow) */
+ /*
+ * Our PAE-style level 2, 5 contiguous pages (4 L2 + 1 shadow).
+ * +-----------------+----------------+---------+
+ * Physical layout: | 3 * USERLAND L2 | L2 KERN SHADOW | L2 KERN |
+ * +-----------------+----------------+---------+
+ * However, we enter pdtpte[3] into L2 KERN, and not L2 KERN SHADOW.
+ * This way, pde[L2_SLOT_KERN] always points to the shadow.
+ */
pde = (pd_entry_t *)avail;
memset(pde, 0, PAGE_SIZE * 5);
avail += PAGE_SIZE * 5;
- addr = ((u_long)pde) - KERNBASE;
/*
- * Enter L2 pages in L3. The real L2 kernel PD will be the last one
- * (so that pde[L2_SLOT_KERN] always points to the shadow).
+ * Link L2 pages in L3, with a special case for L2 KERN. Xen doesn't
+ * want RW permissions in L3 entries, it'll add them itself.
*/
+ addr = ((u_long)pde) - KERNBASE;
for (i = 0; i < 3; i++, addr += PAGE_SIZE) {
- /*
- * Xen doesn't want RW mappings in L3 entries, it'll add it
- * itself.
- */
pdtpe[i] = xpmap_ptom_masked(addr) | PG_k | PG_V;
}
addr += PAGE_SIZE;
@@ -944,15 +947,11 @@ xen_bootstrap_tables(vaddr_t old_pgd, va
/* Install recursive page tables mapping */
#ifdef PAE
- /*
- * We need a shadow page for the kernel's L2 page.
- * The real L2 kernel PD will be the last one (so that
- * pde[L2_SLOT_KERN] always points to the shadow).
- */
+ /* Copy L2 KERN into L2 KERN SHADOW, and reference the latter in cpu0. */
memcpy(&pde[L2_SLOT_KERN + NPDPG], &pde[L2_SLOT_KERN], PAGE_SIZE);
cpu_info_primary.ci_kpm_pdir = &pde[L2_SLOT_KERN + NPDPG];
cpu_info_primary.ci_kpm_pdirpa =
- (vaddr_t) cpu_info_primary.ci_kpm_pdir - KERNBASE;
+ (vaddr_t)cpu_info_primary.ci_kpm_pdir - KERNBASE;
/*
* We don't enter a recursive entry from the L3 PD. Instead, we enter
@@ -965,28 +964,16 @@ xen_bootstrap_tables(vaddr_t old_pgd, va
pde[PDIR_SLOT_PTE + i] = xpmap_ptom_masked(addr) | PG_k | PG_V |
pg_nx;
}
-#if 0
- addr += PAGE_SIZE; /* point to shadow L2 */
- pde[PDIR_SLOT_PTE + 3] = xpmap_ptom_masked(addr) | PG_k | PG_V;
-#endif
- /* Mark tables RO, and pin the kernel's shadow as L2 */
+
+ /* Mark tables RO, and pin L2 KERN SHADOW. */
addr = (u_long)pde - KERNBASE;
for (i = 0; i < 5; i++, addr += PAGE_SIZE) {
xen_bt_set_readonly(((vaddr_t)pde) + PAGE_SIZE * i);
-#if 0
- if (i == 2 || i == 3)
- continue;
- xpq_queue_pin_l2_table(xpmap_ptom_masked(addr));
-#endif
}
if (final) {
addr = (u_long)pde - KERNBASE + 3 * PAGE_SIZE;
xpq_queue_pin_l2_table(xpmap_ptom_masked(addr));
}
-#if 0
- addr = (u_long)pde - KERNBASE + 2 * PAGE_SIZE;
- xpq_queue_pin_l2_table(xpmap_ptom_masked(addr));
-#endif
#else /* PAE */
/* Recursive entry in pmap_kernel(). */
@@ -1000,7 +987,8 @@ xen_bootstrap_tables(vaddr_t old_pgd, va
/* Mark tables RO */
xen_bt_set_readonly((vaddr_t)pde);
-#endif
+#endif /* PAE */
+
#if PTP_LEVELS > 2 || defined(PAE)
xen_bt_set_readonly((vaddr_t)pdtpe);
#endif
