[src/trunk]: src/sys/arch/x86/x86 In addition to %[er]ax, rep xstore-rng al...

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

details:   https://anonhg.NetBSD.org/src/rev/bd5c2624b8f2
branches:  trunk
changeset: 772802:bd5c2624b8f2
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Tue Jan 17 03:39:33 2012 +0000

description:
In addition to %[er]ax,  rep xstore-rng  also clobbers %[er]cx and %[er]di.
As such, mark them as outputs, as is done in the VIA Padlock example code.
Additionally, let's assume that VIAC3_RNG_BUFSIZ is in bytes and not DWords.
Furthermore assume that there are not 1 but NBBY bits of entropy per byte.

Fixes PR kern/45847 for me.

diffstat:

 sys/arch/x86/x86/via_padlock.c |  17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)

diffs (50 lines):

diff -r 468f90d73847 -r bd5c2624b8f2 sys/arch/x86/x86/via_padlock.c
--- a/sys/arch/x86/x86/via_padlock.c    Tue Jan 17 03:06:33 2012 +0000
+++ b/sys/arch/x86/x86/via_padlock.c    Tue Jan 17 03:39:33 2012 +0000
@@ -1,5 +1,5 @@
 /*     $OpenBSD: via.c,v 1.8 2006/11/17 07:47:56 tom Exp $     */
-/*     $NetBSD: via_padlock.c,v 1.19 2012/01/17 03:06:33 jakllsch Exp $ */
+/*     $NetBSD: via_padlock.c,v 1.20 2012/01/17 03:39:33 jakllsch Exp $ */
 
 /*-
  * Copyright (c) 2003 Jason Wright
@@ -20,7 +20,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: via_padlock.c,v 1.19 2012/01/17 03:06:33 jakllsch Exp $");
+__KERNEL_RCSID(0, "$NetBSD: via_padlock.c,v 1.20 2012/01/17 03:39:33 jakllsch Exp $");
 
 #ifdef _KERNEL_OPT
 # include "rnd.h"
@@ -85,8 +85,9 @@
 {
        struct via_padlock_softc *sc = arg;
 
-       unsigned int rv, creg0, len = VIAC3_RNG_BUFSIZ;
-       static uint32_t buffer[VIAC3_RNG_BUFSIZ + 2];   /* XXX 2? */
+       uint32_t creg0, len = VIAC3_RNG_BUFSIZ;
+       uint32_t buffer[VIAC3_RNG_BUFSIZ/4 + 1]; /* CPU goes 3 bytes beyond */
+       uint32_t eax, ecx, edi; /* XXX write-only, but necessary it seems */
 
        /*
         * Sadly, we have to monkey with the coprocessor enable and fault
@@ -109,14 +110,14 @@
         * if we will feed the data to SHA1?) (%edx[0,1] = "11").
         */
        __asm __volatile("rep xstorerng"
-                        : "=a" (rv) : "d" (3), "D" (buffer),
-                        "c" (len * sizeof(int)) : "memory", "cc");
+                        : "=a" (eax), "=c" (ecx), "=D" (edi)
+                        : "d" (3), "D" (buffer), "c" (len)
+                        : "memory", "cc");
        /* Put CR0 back how it was */
        lcr0(creg0);
        x86_enable_intr();
        kpreempt_enable();
-       rnd_add_data(&sc->sc_rnd_source, buffer, len * sizeof(int),
-                    len * sizeof(int));
+       rnd_add_data(&sc->sc_rnd_source, buffer, len, len * NBBY);
        callout_reset(&sc->sc_rnd_co, sc->sc_rnd_hz, via_c3_rnd, sc);
 }