[src/trunk]: src/sys/arch Kenter local_apic_va to a fake physical page, becau...

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

details:   https://anonhg.NetBSD.org/src/rev/2312f2e5443e
branches:  trunk
changeset: 349473:2312f2e5443e
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Dec 11 08:31:53 2016 +0000

description:
Kenter local_apic_va to a fake physical page, because our x86
implementation expects this va to be valid even if no lapic is present;
which probably is a bug in itself, but let's just reproduce the old
behavior and rehide that bug.

diffstat:

 sys/arch/amd64/amd64/machdep.c |  10 ++++++++--
 sys/arch/i386/i386/machdep.c   |  10 ++++++++--
 sys/arch/x86/x86/pmap.c        |  17 ++++++++++++++---
 3 files changed, 30 insertions(+), 7 deletions(-)

diffs (124 lines):

diff -r b2b6eac62550 -r 2312f2e5443e sys/arch/amd64/amd64/machdep.c
--- a/sys/arch/amd64/amd64/machdep.c    Sun Dec 11 08:30:39 2016 +0000
+++ b/sys/arch/amd64/amd64/machdep.c    Sun Dec 11 08:31:53 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: machdep.c,v 1.235 2016/12/09 17:57:24 maxv Exp $       */
+/*     $NetBSD: machdep.c,v 1.236 2016/12/11 08:31:53 maxv Exp $       */
 
 /*-
  * Copyright (c) 1996, 1997, 1998, 2000, 2006, 2007, 2008, 2011
@@ -111,7 +111,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.235 2016/12/09 17:57:24 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.236 2016/12/11 08:31:53 maxv Exp $");
 
 /* #define XENDEBUG_LOW  */
 
@@ -1537,6 +1537,7 @@
 init_x86_64(paddr_t first_avail)
 {
        extern void consinit(void);
+       extern paddr_t local_apic_pa;
        struct region_descriptor region;
        struct mem_segment_descriptor *ldt_segp;
        int x;
@@ -1639,6 +1640,11 @@
 
        kpreempt_disable();
 
+       pmap_kenter_pa(local_apic_va, local_apic_pa,
+           VM_PROT_READ|VM_PROT_WRITE, 0);
+       pmap_update(pmap_kernel());
+       memset((void *)local_apic_va, 0, PAGE_SIZE);
+
        pmap_kenter_pa(idt_vaddr, idt_paddr, VM_PROT_READ|VM_PROT_WRITE, 0);
        pmap_kenter_pa(gdt_vaddr, gdt_paddr, VM_PROT_READ|VM_PROT_WRITE, 0);
        pmap_kenter_pa(ldt_vaddr, ldt_paddr, VM_PROT_READ|VM_PROT_WRITE, 0);
diff -r b2b6eac62550 -r 2312f2e5443e sys/arch/i386/i386/machdep.c
--- a/sys/arch/i386/i386/machdep.c      Sun Dec 11 08:30:39 2016 +0000
+++ b/sys/arch/i386/i386/machdep.c      Sun Dec 11 08:31:53 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: machdep.c,v 1.764 2016/11/15 15:00:55 maxv Exp $       */
+/*     $NetBSD: machdep.c,v 1.765 2016/12/11 08:31:53 maxv Exp $       */
 
 /*-
  * Copyright (c) 1996, 1997, 1998, 2000, 2004, 2006, 2008, 2009
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.764 2016/11/15 15:00:55 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.765 2016/12/11 08:31:53 maxv Exp $");
 
 #include "opt_beep.h"
 #include "opt_compat_ibcs2.h"
@@ -1131,6 +1131,7 @@
 init386(paddr_t first_avail)
 {
        extern void consinit(void);
+       extern paddr_t local_apic_pa;
        int x;
 #ifndef XEN
        union descriptor *tgdt;
@@ -1301,6 +1302,11 @@
        cpu_info_primary.ci_pmap = pmap_kernel();
 #endif
 
+       pmap_kenter_pa(local_apic_va, local_apic_pa,
+           VM_PROT_READ|VM_PROT_WRITE, 0);
+       pmap_update(pmap_kernel());
+       memset((void *)local_apic_va, 0, PAGE_SIZE);
+
        pmap_kenter_pa(idt_vaddr, idt_paddr, VM_PROT_READ|VM_PROT_WRITE, 0);
        pmap_kenter_pa(gdt_vaddr, gdt_paddr, VM_PROT_READ|VM_PROT_WRITE, 0);
        pmap_kenter_pa(ldt_vaddr, ldt_paddr, VM_PROT_READ|VM_PROT_WRITE, 0);
diff -r b2b6eac62550 -r 2312f2e5443e sys/arch/x86/x86/pmap.c
--- a/sys/arch/x86/x86/pmap.c   Sun Dec 11 08:30:39 2016 +0000
+++ b/sys/arch/x86/x86/pmap.c   Sun Dec 11 08:31:53 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.229 2016/11/25 14:26:53 maxv Exp $  */
+/*     $NetBSD: pmap.c,v 1.230 2016/12/11 08:31:53 maxv Exp $  */
 
 /*-
  * Copyright (c) 2008, 2010, 2016 The NetBSD Foundation, Inc.
@@ -171,7 +171,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.229 2016/11/25 14:26:53 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.230 2016/12/11 08:31:53 maxv Exp $");
 
 #include "opt_user_ldt.h"
 #include "opt_lockdebug.h"
@@ -483,9 +483,10 @@
 static vaddr_t virtual_end __read_mostly;      /* VA of last free KVA */
 
 /*
- * LAPIC virtual address.
+ * LAPIC virtual address, and fake physical address.
  */
 volatile vaddr_t local_apic_va;
+paddr_t local_apic_pa;
 
 /*
  * pool that pmap structures are allocated from
@@ -1467,7 +1468,17 @@
 static void
 pmap_init_lapic(void)
 {
+       /*
+        * On CPUs that have no LAPIC, local_apic_va is never kentered. But our
+        * x86 implementation relies a lot on this address to be valid; so just
+        * allocate a fake physical page that will be kentered into
+        * local_apic_va by machdep.
+        *
+        * If the LAPIC is present, the va will be remapped somewhere else
+        * later in lapic_map.
+        */
        local_apic_va = pmap_bootstrap_valloc(1);
+       local_apic_pa = pmap_bootstrap_palloc(1);
 }
 
 #ifdef __HAVE_DIRECT_MAP