Hello,
There was a discussion some time ago upon my proposal of a clean-up of
mb() and related macros. The conclusion was a rewrite is desireable, but
the patch wasn't accepted and no alternative was proposed.
The need for the update is more and more crucial for me as I have more
and more code to apply to the tree that needs the macros be set somehow.
If there is a design flaw, I'd like to know of it, if there is an
implementation problem, I'm willing to fix it. I'm aware about peripheral
bus-specific coherency problems -- the patch is orthogonal to them and
only addresses the host bus.
Here is an updated version I'm using currently. It's fixed to apply
against the current tree and adds <asm-mips64/wbflush.h> for source code
compatibility.
Maciej
--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +
patch-mips-2.4.18-20020530-mb-wb-8
diff -up --recursive --new-file linux-mips-2.4.18-20020530.macro/arch/mips/config.in linux-mips-2.4.18-20020530/arch/mips/config.in
--- linux-mips-2.4.18-20020530.macro/arch/mips/config.in 2002-05-30 02:57:35.000000000 +0000
+++ linux-mips-2.4.18-20020530/arch/mips/config.in 2002-06-02 15:51:03.000000000 +0000
@@ -393,6 +393,11 @@ else
fi
fi
fi
+if [ "$CONFIG_CPU_R3000" = "y" ]; then
+ define_bool CONFIG_CPU_HAS_SYNC n
+else
+ define_bool CONFIG_CPU_HAS_SYNC y
+fi
endmenu
mainmenu_option next_comment
diff -up --recursive --new-file linux-mips-2.4.18-20020530.macro/include/asm-mips/system.h linux-mips-2.4.18-20020530/include/asm-mips/system.h
--- linux-mips-2.4.18-20020530.macro/include/asm-mips/system.h 2002-05-28 10:13:21.000000000 +0000
+++ linux-mips-2.4.18-20020530/include/asm-mips/system.h 2002-06-02 15:51:03.000000000 +0000
@@ -18,9 +18,12 @@
#include <linux/config.h>
#include <asm/sgidefs.h>
-#include <asm/ptrace.h>
+
#include <linux/kernel.h>
+#include <asm/addrspace.h>
+#include <asm/ptrace.h>
+
__asm__ (
".macro\t__sti\n\t"
".set\tpush\n\t"
@@ -166,32 +169,58 @@ extern void __global_restore_flags(unsig
#define local_irq_disable() __cli()
#define local_irq_enable() __sti()
-/*
- * These are probably defined overly paranoid ...
- */
+#ifdef CONFIG_CPU_HAS_SYNC
+#define __sync() \
+ __asm__ __volatile__( \
+ ".set push\n\t" \
+ ".set noreorder\n\t" \
+ ".set mips2\n\t" \
+ "sync\n\t" \
+ ".set pop" \
+ : /* no output */ \
+ : /* no input */ \
+ : "memory")
+#else
+#define __sync() do { } while(0)
+#endif
+
+#define __fast_iob() \
+ __asm__ __volatile__( \
+ ".set push\n\t" \
+ ".set noreorder\n\t" \
+ "lw $0,%0\n\t" \
+ "nop\n\t" \
+ ".set pop" \
+ : /* no output */ \
+ : "m" (*(int *)KSEG1) \
+ : "memory")
+
+#define fast_wmb() __sync()
+#define fast_rmb() __sync()
+#define fast_mb() __sync()
+#define fast_iob() \
+ do { \
+ __sync(); \
+ __fast_iob(); \
+ } while (0)
+
#ifdef CONFIG_CPU_HAS_WB
#include <asm/wbflush.h>
-#define rmb() do { } while(0)
-#define wmb() wbflush()
-#define mb() wbflush()
-
-#else /* CONFIG_CPU_HAS_WB */
-
-#define mb() \
-__asm__ __volatile__( \
- "# prevent instructions being moved around\n\t" \
- ".set\tnoreorder\n\t" \
- "# 8 nops to fool the R4400 pipeline\n\t" \
- "nop;nop;nop;nop;nop;nop;nop;nop\n\t" \
- ".set\treorder" \
- : /* no output */ \
- : /* no input */ \
- : "memory")
-#define rmb() mb()
-#define wmb() mb()
-#endif /* CONFIG_CPU_HAS_WB */
+#define wmb() fast_wmb()
+#define rmb() fast_rmb()
+#define mb() wbflush();
+#define iob() wbflush();
+
+#else /* !CONFIG_CPU_HAS_WB */
+
+#define wmb() fast_wmb()
+#define rmb() fast_rmb()
+#define mb() fast_mb()
+#define iob() fast_iob()
+
+#endif /* !CONFIG_CPU_HAS_WB */
#ifdef CONFIG_SMP
#define smp_mb() mb()
diff -up --recursive --new-file linux-mips-2.4.18-20020530.macro/include/asm-mips/wbflush.h linux-mips-2.4.18-20020530/include/asm-mips/wbflush.h
--- linux-mips-2.4.18-20020530.macro/include/asm-mips/wbflush.h 2001-09-07 04:26:33.000000000 +0000
+++ linux-mips-2.4.18-20020530/include/asm-mips/wbflush.h 2002-02-04 02:52:11.000000000 +0000
@@ -6,29 +6,30 @@
* for more details.
*
* Copyright (c) 1998 Harald Koerfgen
+ * Copyright (C) 2002 Maciej W. Rozycki
*/
#ifndef __ASM_MIPS_WBFLUSH_H
#define __ASM_MIPS_WBFLUSH_H
#include <linux/config.h>
-#if defined(CONFIG_CPU_HAS_WB)
-/*
- * R2000 or R3000
- */
-extern void (*__wbflush) (void);
+#ifdef CONFIG_CPU_HAS_WB
-#define wbflush() __wbflush()
+extern void (*__wbflush)(void);
+extern void wbflush_setup(void);
-#else
-/*
- * we don't need no stinkin' wbflush
- */
+#define wbflush() \
+ do { \
+ __sync(); \
+ __wbflush(); \
+ } while (0)
-#define wbflush() do { } while(0)
+#else /* !CONFIG_CPU_HAS_WB */
-#endif
+#define wbflush_setup() do { } while (0)
-extern void wbflush_setup(void);
+#define wbflush() fast_iob()
+
+#endif /* !CONFIG_CPU_HAS_WB */
#endif /* __ASM_MIPS_WBFLUSH_H */
diff -up --recursive --new-file linux-mips-2.4.18-20020530.macro/include/asm-mips64/system.h linux-mips-2.4.18-20020530/include/asm-mips64/system.h
--- linux-mips-2.4.18-20020530.macro/include/asm-mips64/system.h 2002-05-28 10:13:22.000000000 +0000
+++ linux-mips-2.4.18-20020530/include/asm-mips64/system.h 2002-06-02 15:55:32.000000000 +0000
@@ -12,9 +12,12 @@
#include <linux/config.h>
#include <asm/sgidefs.h>
-#include <asm/ptrace.h>
+
#include <linux/kernel.h>
+#include <asm/addrspace.h>
+#include <asm/ptrace.h>
+
__asm__ (
".macro\t__sti\n\t"
".set\tpush\n\t"
@@ -161,20 +164,37 @@ extern void __global_restore_flags(unsig
#define local_irq_disable() __cli()
#define local_irq_enable() __sti()
-/*
- * These are probably defined overly paranoid ...
- */
-#define mb() \
-__asm__ __volatile__( \
- "# prevent instructions being moved around\n\t" \
- ".set\tnoreorder\n\t" \
- "sync\n\t" \
- ".set\treorder" \
- : /* no output */ \
- : /* no input */ \
- : "memory")
-#define rmb() mb()
-#define wmb() mb()
+#define __sync() \
+ __asm__ __volatile__( \
+ ".set push\n\t" \
+ ".set noreorder\n\t" \
+ "sync\n\t" \
+ ".set pop" \
+ : /* no output */ \
+ : /* no input */ \
+ : "memory")
+
+#define fast_wmb() __sync()
+#define fast_rmb() __sync()
+#define fast_mb() __sync()
+#define fast_iob() \
+ do { \
+ __sync(); \
+ __asm__ __volatile__( \
+ ".set push\n\t" \
+ ".set noreorder\n\t" \
+ "lw $0,%0\n\t" \
+ "nop\n\t" \
+ ".set pop" \
+ : /* no output */ \
+ : "m" (*(int *)KSEG1) \
+ : "memory"); \
+ } while (0)
+
+#define wmb() fast_wmb()
+#define rmb() fast_rmb()
+#define mb() fast_mb()
+#define iob() fast_iob()
#ifdef CONFIG_SMP
#define smp_mb() mb()
diff -up --recursive --new-file linux-mips-2.4.18-20020530.macro/include/asm-mips64/wbflush.h linux-mips-2.4.18-20020530/include/asm-mips64/wbflush.h
--- linux-mips-2.4.18-20020530.macro/include/asm-mips64/wbflush.h 1970-01-01 00:00:00.000000000 +0000
+++ linux-mips-2.4.18-20020530/include/asm-mips64/wbflush.h 2002-05-31 11:43:50.000000000 +0000
@@ -0,0 +1,18 @@
+/*
+ * Header file for using the wbflush routine
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1998 Harald Koerfgen
+ * Copyright (C) 2002 Maciej W. Rozycki
+ */
+#ifndef __ASM_MIPS64_WBFLUSH_H
+#define __ASM_MIPS64_WBFLUSH_H
+
+#define wbflush_setup() do { } while (0)
+
+#define wbflush() fast_iob()
+
+#endif /* __ASM_MIPS64_WBFLUSH_H */
