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openwrt-owl/target/linux/generic/patches-3.3/003-MIPS-Refactor-clear_pag...

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From c022630633624a75b3b58f43dd3c6cc896a56cff Mon Sep 17 00:00:00 2001
From: "Steven J. Hill" <sjhill@mips.com>
Date: Fri, 6 Jul 2012 21:56:01 +0200
Subject: [PATCH] MIPS: Refactor 'clear_page' and 'copy_page' functions.
Remove usage of the '__attribute__((alias("...")))' hack that aliased
to integer arrays containing micro-assembled instructions. This hack
breaks when building a microMIPS kernel. It also makes the code much
easier to understand.
[ralf@linux-mips.org: Added back export of the clear_page and copy_page
symbols so certain modules will work again. Also fixed build with
CONFIG_SIBYTE_DMA_PAGEOPS enabled.]
Signed-off-by: Steven J. Hill <sjhill@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3866/
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
arch/mips/kernel/mips_ksyms.c | 8 ++++-
arch/mips/mm/Makefile | 4 +--
arch/mips/mm/page-funcs.S | 50 ++++++++++++++++++++++++++++++
arch/mips/mm/page.c | 67 +++++++++++------------------------------
4 files changed, 77 insertions(+), 52 deletions(-)
create mode 100644 arch/mips/mm/page-funcs.S
--- a/arch/mips/kernel/mips_ksyms.c
+++ b/arch/mips/kernel/mips_ksyms.c
@@ -5,7 +5,7 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
- * Copyright (C) 1996, 97, 98, 99, 2000, 01, 03, 04, 05 by Ralf Baechle
+ * Copyright (C) 1996, 97, 98, 99, 2000, 01, 03, 04, 05, 12 by Ralf Baechle
* Copyright (C) 1999, 2000, 01 Silicon Graphics, Inc.
*/
#include <linux/interrupt.h>
@@ -35,6 +35,12 @@ EXPORT_SYMBOL(memmove);
EXPORT_SYMBOL(kernel_thread);
/*
+ * Functions that operate on entire pages. Mostly used by memory management.
+ */
+EXPORT_SYMBOL(clear_page);
+EXPORT_SYMBOL(copy_page);
+
+/*
* Userspace access stuff.
*/
EXPORT_SYMBOL(__copy_user);
--- a/arch/mips/mm/Makefile
+++ b/arch/mips/mm/Makefile
@@ -3,8 +3,8 @@
#
obj-y += cache.o dma-default.o extable.o fault.o \
- gup.o init.o mmap.o page.o tlbex.o \
- tlbex-fault.o uasm.o
+ gup.o init.o mmap.o page.o page-funcs.o \
+ tlbex.o tlbex-fault.o uasm.o
obj-$(CONFIG_32BIT) += ioremap.o pgtable-32.o
obj-$(CONFIG_64BIT) += pgtable-64.o
--- /dev/null
+++ b/arch/mips/mm/page-funcs.S
@@ -0,0 +1,50 @@
+/*
+ * 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.
+ *
+ * Micro-assembler generated clear_page/copy_page functions.
+ *
+ * Copyright (C) 2012 MIPS Technologies, Inc.
+ * Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org>
+ */
+#include <asm/asm.h>
+#include <asm/regdef.h>
+
+#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
+#define cpu_clear_page_function_name clear_page_cpu
+#define cpu_copy_page_function_name copy_page_cpu
+#else
+#define cpu_clear_page_function_name clear_page
+#define cpu_copy_page_function_name copy_page
+#endif
+
+/*
+ * Maximum sizes:
+ *
+ * R4000 128 bytes S-cache: 0x058 bytes
+ * R4600 v1.7: 0x05c bytes
+ * R4600 v2.0: 0x060 bytes
+ * With prefetching, 16 word strides 0x120 bytes
+ */
+EXPORT(__clear_page_start)
+LEAF(cpu_clear_page_function_name)
+1: j 1b /* Dummy, will be replaced. */
+ .space 288
+END(cpu_clear_page_function_name)
+EXPORT(__clear_page_end)
+
+/*
+ * Maximum sizes:
+ *
+ * R4000 128 bytes S-cache: 0x11c bytes
+ * R4600 v1.7: 0x080 bytes
+ * R4600 v2.0: 0x07c bytes
+ * With prefetching, 16 word strides 0x540 bytes
+ */
+EXPORT(__copy_page_start)
+LEAF(cpu_copy_page_function_name)
+1: j 1b /* Dummy, will be replaced. */
+ .space 1344
+END(cpu_copy_page_function_name)
+EXPORT(__copy_page_end)
--- a/arch/mips/mm/page.c
+++ b/arch/mips/mm/page.c
@@ -6,6 +6,7 @@
* Copyright (C) 2003, 04, 05 Ralf Baechle (ralf@linux-mips.org)
* Copyright (C) 2007 Maciej W. Rozycki
* Copyright (C) 2008 Thiemo Seufer
+ * Copyright (C) 2012 MIPS Technologies, Inc.
*/
#include <linux/init.h>
#include <linux/kernel.h>
@@ -72,45 +73,6 @@ static struct uasm_reloc __cpuinitdata r
#define cpu_is_r4600_v1_x() ((read_c0_prid() & 0xfffffff0) == 0x00002010)
#define cpu_is_r4600_v2_x() ((read_c0_prid() & 0xfffffff0) == 0x00002020)
-/*
- * Maximum sizes:
- *
- * R4000 128 bytes S-cache: 0x058 bytes
- * R4600 v1.7: 0x05c bytes
- * R4600 v2.0: 0x060 bytes
- * With prefetching, 16 word strides 0x120 bytes
- */
-
-static u32 clear_page_array[0x120 / 4];
-
-#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
-void clear_page_cpu(void *page) __attribute__((alias("clear_page_array")));
-#else
-void clear_page(void *page) __attribute__((alias("clear_page_array")));
-#endif
-
-EXPORT_SYMBOL(clear_page);
-
-/*
- * Maximum sizes:
- *
- * R4000 128 bytes S-cache: 0x11c bytes
- * R4600 v1.7: 0x080 bytes
- * R4600 v2.0: 0x07c bytes
- * With prefetching, 16 word strides 0x540 bytes
- */
-static u32 copy_page_array[0x540 / 4];
-
-#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
-void
-copy_page_cpu(void *to, void *from) __attribute__((alias("copy_page_array")));
-#else
-void copy_page(void *to, void *from) __attribute__((alias("copy_page_array")));
-#endif
-
-EXPORT_SYMBOL(copy_page);
-
-
static int pref_bias_clear_store __cpuinitdata;
static int pref_bias_copy_load __cpuinitdata;
static int pref_bias_copy_store __cpuinitdata;
@@ -283,10 +245,15 @@ static inline void __cpuinit build_clear
}
}
+extern u32 __clear_page_start;
+extern u32 __clear_page_end;
+extern u32 __copy_page_start;
+extern u32 __copy_page_end;
+
void __cpuinit build_clear_page(void)
{
int off;
- u32 *buf = (u32 *)&clear_page_array;
+ u32 *buf = &__clear_page_start;
struct uasm_label *l = labels;
struct uasm_reloc *r = relocs;
int i;
@@ -357,17 +324,17 @@ void __cpuinit build_clear_page(void)
uasm_i_jr(&buf, RA);
uasm_i_nop(&buf);
- BUG_ON(buf > clear_page_array + ARRAY_SIZE(clear_page_array));
+ BUG_ON(buf > &__clear_page_end);
uasm_resolve_relocs(relocs, labels);
pr_debug("Synthesized clear page handler (%u instructions).\n",
- (u32)(buf - clear_page_array));
+ (u32)(buf - &__clear_page_start));
pr_debug("\t.set push\n");
pr_debug("\t.set noreorder\n");
- for (i = 0; i < (buf - clear_page_array); i++)
- pr_debug("\t.word 0x%08x\n", clear_page_array[i]);
+ for (i = 0; i < (buf - &__clear_page_start); i++)
+ pr_debug("\t.word 0x%08x\n", (&__clear_page_start)[i]);
pr_debug("\t.set pop\n");
}
@@ -428,7 +395,7 @@ static inline void build_copy_store_pref
void __cpuinit build_copy_page(void)
{
int off;
- u32 *buf = (u32 *)&copy_page_array;
+ u32 *buf = &__copy_page_start;
struct uasm_label *l = labels;
struct uasm_reloc *r = relocs;
int i;
@@ -596,21 +563,23 @@ void __cpuinit build_copy_page(void)
uasm_i_jr(&buf, RA);
uasm_i_nop(&buf);
- BUG_ON(buf > copy_page_array + ARRAY_SIZE(copy_page_array));
+ BUG_ON(buf > &__copy_page_end);
uasm_resolve_relocs(relocs, labels);
pr_debug("Synthesized copy page handler (%u instructions).\n",
- (u32)(buf - copy_page_array));
+ (u32)(buf - &__copy_page_start));
pr_debug("\t.set push\n");
pr_debug("\t.set noreorder\n");
- for (i = 0; i < (buf - copy_page_array); i++)
- pr_debug("\t.word 0x%08x\n", copy_page_array[i]);
+ for (i = 0; i < (buf - &__copy_page_start); i++)
+ pr_debug("\t.word 0x%08x\n", (&__copy_page_start)[i]);
pr_debug("\t.set pop\n");
}
#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
+extern void clear_page_cpu(void *page);
+extern void copy_page_cpu(void *to, void *from);
/*
* Pad descriptors to cacheline, since each is exclusively owned by a
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