[src/trunk]: src/sys/arch/x86/x86 Implement pmap_kenter_pa(9) new flag argume...

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

details:   https://anonhg.NetBSD.org/src/rev/b7feb93c423e
branches:  trunk
changeset: 748854:b7feb93c423e
user:      cegger <cegger%NetBSD.org@localhost>
date:      Sat Nov 07 07:32:53 2009 +0000

description:
Implement pmap_kenter_pa(9) new flag argument in x86.
Make x86 bus_space(9) using it to eliminate an extra TLB flush.
Patch showed on tech-kern@ http://mail-index.netbsd.org/tech-kern/2009/11/04/msg006434.html
Thanks to Martin Husemann for spotting copy&pasto errors in the original patch version.

diffstat:

 sys/arch/x86/x86/bus_space.c |  37 ++++++++++---------------------------
 sys/arch/x86/x86/pmap.c      |   9 +++++++--
 2 files changed, 17 insertions(+), 29 deletions(-)

diffs (111 lines):

diff -r 5b0fe603c714 -r b7feb93c423e sys/arch/x86/x86/bus_space.c
--- a/sys/arch/x86/x86/bus_space.c      Sat Nov 07 07:27:40 2009 +0000
+++ b/sys/arch/x86/x86/bus_space.c      Sat Nov 07 07:32:53 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bus_space.c,v 1.25 2009/11/07 07:27:48 cegger Exp $    */
+/*     $NetBSD: bus_space.c,v 1.26 2009/11/07 07:32:53 cegger Exp $    */
 
 /*-
  * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: bus_space.c,v 1.25 2009/11/07 07:27:48 cegger Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bus_space.c,v 1.26 2009/11/07 07:32:53 cegger Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -293,11 +293,14 @@
 {
        paddr_t pa, endpa;
        vaddr_t va, sva;
-       pt_entry_t *pte, xpte;
+       u_int pmapflags = 0;
 
        pa = x86_trunc_page(bpa);
        endpa = x86_round_page(bpa + size);
 
+       if (!cacheable)
+               pmapflags |= PMAP_NOCACHE;
+
 #ifdef DIAGNOSTIC
        if (endpa != 0 && endpa <= pa)
                panic("x86_mem_add_mapping: overflow");
@@ -316,35 +319,15 @@
        }
 
        *bshp = (bus_space_handle_t)(sva + (bpa & PGOFSET));
-       va = sva;
-       xpte = 0;
 
-       for (; pa != endpa; pa += PAGE_SIZE, va += PAGE_SIZE) {
-               /*
-                * PG_N doesn't exist on 386's, so we assume that
-                * the mainboard has wired up device space non-cacheable
-                * on those machines.
-                *
-                * XXX should hand this bit to pmap_kenter_pa to
-                * save the extra invalidate!
-                */
+       for (va = sva; pa != endpa; pa += PAGE_SIZE, va += PAGE_SIZE) {
 #ifdef XEN
-               pmap_kenter_ma(va, pa, VM_PROT_READ | VM_PROT_WRITE, 0);
+               pmap_kenter_ma(va, pa, VM_PROT_READ | VM_PROT_WRITE, pmapflags);
 #else
-               pmap_kenter_pa(va, pa, VM_PROT_READ | VM_PROT_WRITE, 0);
+               pmap_kenter_pa(va, pa, VM_PROT_READ | VM_PROT_WRITE, pmapflags);
 #endif /* XEN */
-
-               pte = kvtopte(va);
-               if (cacheable)
-                       pmap_pte_clearbits(pte, PG_N);
-               else
-                       pmap_pte_setbits(pte, PG_N);
-               xpte |= *pte;
        }
-       kpreempt_disable();
-       pmap_tlb_shootdown(pmap_kernel(), sva, sva + (endpa - pa), xpte);
-       pmap_tlb_shootwait();
-       kpreempt_enable();
+       pmap_update(pmap_kernel());
 
        return 0;
 }
diff -r 5b0fe603c714 -r b7feb93c423e sys/arch/x86/x86/pmap.c
--- a/sys/arch/x86/x86/pmap.c   Sat Nov 07 07:27:40 2009 +0000
+++ b/sys/arch/x86/x86/pmap.c   Sat Nov 07 07:32:53 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.95 2009/11/07 07:27:49 cegger Exp $ */
+/*     $NetBSD: pmap.c,v 1.96 2009/11/07 07:32:53 cegger Exp $ */
 
 /*
  * Copyright (c) 2007 Manuel Bouyer.
@@ -149,7 +149,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.95 2009/11/07 07:27:49 cegger Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.96 2009/11/07 07:32:53 cegger Exp $");
 
 #include "opt_user_ldt.h"
 #include "opt_lockdebug.h"
@@ -1030,6 +1030,8 @@
 #endif /* DOM0OPS */
                npte = pmap_pa2pte(pa);
        npte |= protection_codes[prot] | PG_k | PG_V | pmap_pg_g;
+       if (flags & PMAP_NOCACHE)
+               npte |= PG_N;
        opte = pmap_pte_testset(pte, npte); /* zap! */
 #if defined(DIAGNOSTIC)
        /* XXX For now... */
@@ -1125,6 +1127,9 @@
 
        npte = ma | ((prot & VM_PROT_WRITE) ? PG_RW : PG_RO) |
             PG_V | PG_k;
+       if (flags & PMAP_NOCACHE)
+               npte |= PG_N;
+
 #ifndef XEN
        if ((cpu_feature & CPUID_NOX) && !(prot & VM_PROT_EXECUTE))
                npte |= PG_NX;