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issue memory read barrier for BUS_DMASYNC_POSTREAD operation. 

PR/21665 from Stephan Uphoff.
This commit is contained in:
yamt 2004-01-14 11:31:55 +00:00
parent 6125e101f7
commit 7246e2cc80
3 changed files with 38 additions and 6 deletions
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14
sys/arch/amd64/include/cpufunc.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: cpufunc.h,v 1.3 2003/05/08 10:27:43 fvdl Exp $ */
/* $NetBSD: cpufunc.h,v 1.4 2004/01/14 11:31:55 yamt Exp $ */
/*-
* Copyright (c) 1998 The NetBSD Foundation, Inc.
@ -54,6 +54,18 @@ x86_pause(void)
/* nothing */
}
static __inline void
x86_lfence(void)
{
/*
* XXX if lfence isn't available...
*
* memory clobber to avoid compiler reordering.
*/
__asm __volatile("lfence" : : : "memory");
}
#ifdef _KERNEL
extern int cpu_feature;

12
sys/arch/i386/include/cpufunc.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: cpufunc.h,v 1.27 2003/10/27 13:44:20 junyoung Exp $ */
/* $NetBSD: cpufunc.h,v 1.28 2004/01/14 11:31:55 yamt Exp $ */
/*-
* Copyright (c) 1998 The NetBSD Foundation, Inc.
@ -54,6 +54,16 @@ x86_pause(void)
__asm __volatile("pause");
}
static __inline void
x86_lfence(void)
{
/*
* XXX it's better to use real lfence insn if available.
*/
__asm __volatile("lock; addl $0, 0(%%esp)" : : : "memory");
}
#ifdef _KERNEL
extern unsigned int cpu_feature;

18
sys/arch/x86/include/bus.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: bus.h,v 1.4 2003/10/27 13:43:48 junyoung Exp $ */
/* $NetBSD: bus.h,v 1.5 2004/01/14 11:31:55 yamt Exp $ */
/*-
* Copyright (c) 1996, 1997, 1998, 2001 The NetBSD Foundation, Inc.
@ -72,6 +72,7 @@
#define _X86_BUS_H_
#include <machine/pio.h>
#include <machine/cpufunc.h> /* for x86_lfence */
#ifdef BUS_SPACE_DEBUG
#include <sys/systm.h> /* for printf() prototype */
@ -1109,6 +1110,9 @@ struct x86_bus_dma_tag {
int, off_t, int, int);
};
static __inline void bus_dmamap_sync(bus_dma_tag_t, bus_dmamap_t,
bus_addr_t, bus_size_t, int) __attribute__((__unused__));
#define bus_dmamap_create(t, s, n, m, b, f, p) \
(*(t)->_dmamap_create)((t), (s), (n), (m), (b), (f), (p))
#define bus_dmamap_destroy(t, p) \
@ -1123,9 +1127,15 @@ struct x86_bus_dma_tag {
(*(t)->_dmamap_load_raw)((t), (m), (sg), (n), (s), (f))
#define bus_dmamap_unload(t, p) \
(*(t)->_dmamap_unload)((t), (p))
#define bus_dmamap_sync(t, p, o, l, ops) \
(void)((t)->_dmamap_sync ? \
(*(t)->_dmamap_sync)((t), (p), (o), (l), (ops)) : (void)0)
static __inline void
bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t p, bus_addr_t o, bus_size_t l,
int ops)
{
if (ops & BUS_DMASYNC_POSTREAD)
x86_lfence();
if (t->_dmamap_sync)
(*t->_dmamap_sync)(t, p, o, l, ops);
}
#define bus_dmamem_alloc(t, s, a, b, sg, n, r, f) \
(*(t)->_dmamem_alloc)((t), (s), (a), (b), (sg), (n), (r), (f))