[src/trunk]: src/sys/arch/xen/x86 Export xpmap_pg_nx, and put it in the page ...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d4473a86bdd0
branches:  trunk
changeset: 821058:d4473a86bdd0
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Jan 22 19:24:51 2017 +0000

description:
Export xpmap_pg_nx, and put it in the page table pages. It does not change
anything, since Xen removes the X bit on these; but it is better for
consistency.

diffstat:

 sys/arch/xen/x86/x86_xpmap.c |  48 ++++++++++++++++++-------------------------
 1 files changed, 20 insertions(+), 28 deletions(-)

diffs (151 lines):

diff -r eb4248a7eb80 -r d4473a86bdd0 sys/arch/xen/x86/x86_xpmap.c
--- a/sys/arch/xen/x86/x86_xpmap.c      Sun Jan 22 17:46:20 2017 +0000
+++ b/sys/arch/xen/x86/x86_xpmap.c      Sun Jan 22 19:24:51 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: x86_xpmap.c,v 1.69 2017/01/06 08:32:26 maxv Exp $      */
+/*     $NetBSD: x86_xpmap.c,v 1.70 2017/01/22 19:24:51 maxv Exp $      */
 
 /*
  * Copyright (c) 2006 Mathieu Ropert <mro%adviseo.fr@localhost>
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: x86_xpmap.c,v 1.69 2017/01/06 08:32:26 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: x86_xpmap.c,v 1.70 2017/01/22 19:24:51 maxv Exp $");
 
 #include "opt_xen.h"
 #include "opt_ddb.h"
@@ -105,6 +105,8 @@
 kmutex_t pte_lock;
 vaddr_t xen_dummy_page;
 
+pt_entry_t xpmap_pg_nx;
+
 void xen_failsafe_handler(void);
 
 #define HYPERVISOR_mmu_update_self(req, count, success_count) \
@@ -609,6 +611,7 @@
 {
        size_t count, oldcount, mapsize;
        vaddr_t bootstrap_tables, init_tables;
+       u_int descs[4];
 
        xen_init_features();
 
@@ -617,6 +620,10 @@
        xpmap_phys_to_machine_mapping =
            (unsigned long *)xen_start_info.mfn_list;
 
+       /* Set the NX/XD bit, if available. descs[3] = %edx. */
+       x86_cpuid(0x80000001, descs);
+       xpmap_pg_nx = (descs[3] & CPUID_NOX) ? PG_NX : 0;
+
        /* Space after Xen boostrap tables should be free */
        init_tables = xen_start_info.pt_base;
        bootstrap_tables = init_tables +
@@ -738,14 +745,6 @@
        extern char __data_start;
        extern char __kernel_end;
        extern char *early_zerop; /* from pmap.c */
-       pt_entry_t pg_nx;
-       u_int descs[4];
-
-       /*
-        * Set the NX/XD bit, if available. descs[3] = %edx.
-        */
-       x86_cpuid(0x80000001, descs);
-       pg_nx = (descs[3] & CPUID_NOX) ? PG_NX : 0;
 
        /*
         * Layout of RW area after the kernel image:
@@ -895,7 +894,7 @@
                            page < (vaddr_t)atdevbase + IOM_SIZE) {
                                pte[pl1_pi(page)] =
                                    IOM_BEGIN + (page - (vaddr_t)atdevbase);
-                               pte[pl1_pi(page)] |= pg_nx;
+                               pte[pl1_pi(page)] |= xpmap_pg_nx;
                        }
 #endif
 
@@ -906,15 +905,15 @@
                        } else if (page >= (vaddr_t)&__rodata_start &&
                            page < (vaddr_t)&__data_start) {
                                /* Map the kernel rodata R. */
-                               pte[pl1_pi(page)] |= PG_RO | pg_nx;
+                               pte[pl1_pi(page)] |= PG_RO | xpmap_pg_nx;
                        } else if (page >= old_pgd &&
                            page < old_pgd + (old_count * PAGE_SIZE)) {
                                /* Map the old page tables R. */
-                               pte[pl1_pi(page)] |= PG_RO | pg_nx;
+                               pte[pl1_pi(page)] |= PG_RO | xpmap_pg_nx;
                        } else if (page >= new_pgd &&
                            page < new_pgd + ((new_count + l2_4_count) * PAGE_SIZE)) {
                                /* Map the new page tables R. */
-                               pte[pl1_pi(page)] |= PG_RO | pg_nx;
+                               pte[pl1_pi(page)] |= PG_RO | xpmap_pg_nx;
 #ifdef i386
                        } else if (page == (vaddr_t)tmpgdt) {
                                /*
@@ -928,10 +927,10 @@
                        } else if (page >= (vaddr_t)&__data_start &&
                            page < (vaddr_t)&__kernel_end) {
                                /* Map the kernel data+bss RW. */
-                               pte[pl1_pi(page)] |= PG_RW | pg_nx;
+                               pte[pl1_pi(page)] |= PG_RW | xpmap_pg_nx;
                        } else {
                                /* Map the page RW. */
-                               pte[pl1_pi(page)] |= PG_RW | pg_nx;
+                               pte[pl1_pi(page)] |= PG_RW | xpmap_pg_nx;
                        }
 
                        page += PAGE_SIZE;
@@ -962,7 +961,7 @@
        addr = (u_long)pde - KERNBASE;
        for (i = 0; i < 3; i++, addr += PAGE_SIZE) {
                pde[PDIR_SLOT_PTE + i] = xpmap_ptom_masked(addr) | PG_k | PG_V |
-                   pg_nx;
+                   xpmap_pg_nx;
        }
 
        /* Mark tables RO, and pin L2 KERN SHADOW. */
@@ -978,11 +977,11 @@
 
        /* Recursive entry in pmap_kernel(). */
        bt_pgd[PDIR_SLOT_PTE] = xpmap_ptom_masked((paddr_t)bt_pgd - KERNBASE)
-           | PG_k | PG_RO | PG_V | pg_nx;
+           | PG_k | PG_RO | PG_V | xpmap_pg_nx;
 #ifdef __x86_64__
        /* Recursive entry in higher-level per-cpu PD. */
        bt_cpu_pgd[PDIR_SLOT_PTE] = xpmap_ptom_masked((paddr_t)bt_cpu_pgd - KERNBASE)
-           | PG_k | PG_RO | PG_V | pg_nx;
+           | PG_k | PG_RO | PG_V | xpmap_pg_nx;
 #endif
 
        /* Mark tables RO */
@@ -1061,23 +1060,16 @@
        xpq_flush_queue();
 }
 
-
 /*
- * Bootstrap helper functions
+ * Mark a page read-only, assuming vaddr = paddr + KERNBASE.
  */
-
-/*
- * Mark a page readonly
- * XXX: assuming vaddr = paddr + KERNBASE
- */
-
 static void
 xen_bt_set_readonly(vaddr_t page)
 {
        pt_entry_t entry;
 
        entry = xpmap_ptom_masked(page - KERNBASE);
-       entry |= PG_k | PG_V;
+       entry |= PG_k | PG_V | xpmap_pg_nx;
 
        HYPERVISOR_update_va_mapping(page, entry, UVMF_INVLPG);
 }