target/linux/generic/patches-3.3/003-MIPS-Refactor-clear_page-and-copy_page-functions.patch

   1 From c022630633624a75b3b58f43dd3c6cc896a56cff Mon Sep 17 00:00:00 2001
   2 From: "Steven J. Hill" <sjhill@mips.com>
   3 Date: Fri, 6 Jul 2012 21:56:01 +0200
   4 Subject: [PATCH] MIPS: Refactor 'clear_page' and 'copy_page' functions.
   5
   6 Remove usage of the '__attribute__((alias("...")))' hack that aliased
   7 to integer arrays containing micro-assembled instructions. This hack
   8 breaks when building a microMIPS kernel. It also makes the code much
   9 easier to understand.
  10
  11 [ralf@linux-mips.org: Added back export of the clear_page and copy_page
  12 symbols so certain modules will work again.  Also fixed build with
  13 CONFIG_SIBYTE_DMA_PAGEOPS enabled.]
  14
  15 Signed-off-by: Steven J. Hill <sjhill@mips.com>
  16 Cc: linux-mips@linux-mips.org
  17 Patchwork: https://patchwork.linux-mips.org/patch/3866/
  18 Acked-by: David Daney <david.daney@cavium.com>
  19 Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  20 ---
  21  arch/mips/kernel/mips_ksyms.c |    8 ++++-
  22  arch/mips/mm/Makefile         |    4 +--
  23  arch/mips/mm/page-funcs.S     |   50 ++++++++++++++++++++++++++++++
  24  arch/mips/mm/page.c           |   67 +++++++++++------------------------------
  25  4 files changed, 77 insertions(+), 52 deletions(-)
  26  create mode 100644 arch/mips/mm/page-funcs.S
  27
  28 --- a/arch/mips/kernel/mips_ksyms.c
  29 +++ b/arch/mips/kernel/mips_ksyms.c
  30 @@ -5,7 +5,7 @@
  31   * License.  See the file "COPYING" in the main directory of this archive
  32   * for more details.
  33   *
  34 - * Copyright (C) 1996, 97, 98, 99, 2000, 01, 03, 04, 05 by Ralf Baechle
  35 + * Copyright (C) 1996, 97, 98, 99, 2000, 01, 03, 04, 05, 12 by Ralf Baechle
  36   * Copyright (C) 1999, 2000, 01 Silicon Graphics, Inc.
  37   */
  38  #include <linux/interrupt.h>
  39 @@ -35,6 +35,12 @@ EXPORT_SYMBOL(memmove);
  40  EXPORT_SYMBOL(kernel_thread);
  41
  42  /*
  43 + * Functions that operate on entire pages.  Mostly used by memory management.
  44 + */
  45 +EXPORT_SYMBOL(clear_page);
  46 +EXPORT_SYMBOL(copy_page);
  47 +
  48 +/*
  49   * Userspace access stuff.
  50   */
  51  EXPORT_SYMBOL(__copy_user);
  52 --- a/arch/mips/mm/Makefile
  53 +++ b/arch/mips/mm/Makefile
  54 @@ -3,8 +3,8 @@
  55  #
  56
  57  obj-y                          += cache.o dma-default.o extable.o fault.o \
  58 -                                  gup.o init.o mmap.o page.o tlbex.o \
  59 -                                  tlbex-fault.o uasm.o
  60 +                                  gup.o init.o mmap.o page.o page-funcs.o \
  61 +                                  tlbex.o tlbex-fault.o uasm.o
  62
  63  obj-$(CONFIG_32BIT)            += ioremap.o pgtable-32.o
  64  obj-$(CONFIG_64BIT)            += pgtable-64.o
  65 --- /dev/null
  66 +++ b/arch/mips/mm/page-funcs.S
  67 @@ -0,0 +1,50 @@
  68 +/*
  69 + * This file is subject to the terms and conditions of the GNU General Public
  70 + * License.  See the file "COPYING" in the main directory of this archive
  71 + * for more details.
  72 + *
  73 + * Micro-assembler generated clear_page/copy_page functions.
  74 + *
  75 + * Copyright (C) 2012  MIPS Technologies, Inc.
  76 + * Copyright (C) 2012  Ralf Baechle <ralf@linux-mips.org>
  77 + */
  78 +#include <asm/asm.h>
  79 +#include <asm/regdef.h>
  80 +
  81 +#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
  82 +#define cpu_clear_page_function_name   clear_page_cpu
  83 +#define cpu_copy_page_function_name    copy_page_cpu
  84 +#else
  85 +#define cpu_clear_page_function_name   clear_page
  86 +#define cpu_copy_page_function_name    copy_page
  87 +#endif
  88 +
  89 +/*
  90 + * Maximum sizes:
  91 + *
  92 + * R4000 128 bytes S-cache:            0x058 bytes
  93 + * R4600 v1.7:                         0x05c bytes
  94 + * R4600 v2.0:                         0x060 bytes
  95 + * With prefetching, 16 word strides   0x120 bytes
  96 + */
  97 +EXPORT(__clear_page_start)
  98 +LEAF(cpu_clear_page_function_name)
  99 +1:     j       1b              /* Dummy, will be replaced. */
 100 +       .space 288
 101 +END(cpu_clear_page_function_name)
 102 +EXPORT(__clear_page_end)
 103 +
 104 +/*
 105 + * Maximum sizes:
 106 + *
 107 + * R4000 128 bytes S-cache:            0x11c bytes
 108 + * R4600 v1.7:                         0x080 bytes
 109 + * R4600 v2.0:                         0x07c bytes
 110 + * With prefetching, 16 word strides   0x540 bytes
 111 + */
 112 +EXPORT(__copy_page_start)
 113 +LEAF(cpu_copy_page_function_name)
 114 +1:     j       1b              /* Dummy, will be replaced. */
 115 +       .space 1344
 116 +END(cpu_copy_page_function_name)
 117 +EXPORT(__copy_page_end)
 118 --- a/arch/mips/mm/page.c
 119 +++ b/arch/mips/mm/page.c
 120 @@ -6,6 +6,7 @@
 121   * Copyright (C) 2003, 04, 05 Ralf Baechle (ralf@linux-mips.org)
 122   * Copyright (C) 2007  Maciej W. Rozycki
 123   * Copyright (C) 2008  Thiemo Seufer
 124 + * Copyright (C) 2012  MIPS Technologies, Inc.
 125   */
 126  #include <linux/init.h>
 127  #include <linux/kernel.h>
 128 @@ -72,45 +73,6 @@ static struct uasm_reloc __cpuinitdata r
 129  #define cpu_is_r4600_v1_x()    ((read_c0_prid() & 0xfffffff0) == 0x00002010)
 130  #define cpu_is_r4600_v2_x()    ((read_c0_prid() & 0xfffffff0) == 0x00002020)
 131
 132 -/*
 133 - * Maximum sizes:
 134 - *
 135 - * R4000 128 bytes S-cache:            0x058 bytes
 136 - * R4600 v1.7:                         0x05c bytes
 137 - * R4600 v2.0:                         0x060 bytes
 138 - * With prefetching, 16 word strides   0x120 bytes
 139 - */
 140 -
 141 -static u32 clear_page_array[0x120 / 4];
 142 -
 143 -#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
 144 -void clear_page_cpu(void *page) __attribute__((alias("clear_page_array")));
 145 -#else
 146 -void clear_page(void *page) __attribute__((alias("clear_page_array")));
 147 -#endif
 148 -
 149 -EXPORT_SYMBOL(clear_page);
 150 -
 151 -/*
 152 - * Maximum sizes:
 153 - *
 154 - * R4000 128 bytes S-cache:            0x11c bytes
 155 - * R4600 v1.7:                         0x080 bytes
 156 - * R4600 v2.0:                         0x07c bytes
 157 - * With prefetching, 16 word strides   0x540 bytes
 158 - */
 159 -static u32 copy_page_array[0x540 / 4];
 160 -
 161 -#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
 162 -void
 163 -copy_page_cpu(void *to, void *from) __attribute__((alias("copy_page_array")));
 164 -#else
 165 -void copy_page(void *to, void *from) __attribute__((alias("copy_page_array")));
 166 -#endif
 167 -
 168 -EXPORT_SYMBOL(copy_page);
 169 -
 170 -
 171  static int pref_bias_clear_store __cpuinitdata;
 172  static int pref_bias_copy_load __cpuinitdata;
 173  static int pref_bias_copy_store __cpuinitdata;
 174 @@ -283,10 +245,15 @@ static inline void __cpuinit build_clear
 175                 }
 176  }
 177
 178 +extern u32 __clear_page_start;
 179 +extern u32 __clear_page_end;
 180 +extern u32 __copy_page_start;
 181 +extern u32 __copy_page_end;
 182 +
 183  void __cpuinit build_clear_page(void)
 184  {
 185         int off;
 186 -       u32 *buf = (u32 *)&clear_page_array;
 187 +       u32 *buf = &__clear_page_start;
 188         struct uasm_label *l = labels;
 189         struct uasm_reloc *r = relocs;
 190         int i;
 191 @@ -357,17 +324,17 @@ void __cpuinit build_clear_page(void)
 192         uasm_i_jr(&buf, RA);
 193         uasm_i_nop(&buf);
 194
 195 -       BUG_ON(buf > clear_page_array + ARRAY_SIZE(clear_page_array));
 196 +       BUG_ON(buf > &__clear_page_end);
 197
 198         uasm_resolve_relocs(relocs, labels);
 199
 200         pr_debug("Synthesized clear page handler (%u instructions).\n",
 201 -                (u32)(buf - clear_page_array));
 202 +                (u32)(buf - &__clear_page_start));
 203
 204         pr_debug("\t.set push\n");
 205         pr_debug("\t.set noreorder\n");
 206 -       for (i = 0; i < (buf - clear_page_array); i++)
 207 -               pr_debug("\t.word 0x%08x\n", clear_page_array[i]);
 208 +       for (i = 0; i < (buf - &__clear_page_start); i++)
 209 +               pr_debug("\t.word 0x%08x\n", (&__clear_page_start)[i]);
 210         pr_debug("\t.set pop\n");
 211  }
 212
 213 @@ -428,7 +395,7 @@ static inline void build_copy_store_pref
 214  void __cpuinit build_copy_page(void)
 215  {
 216         int off;
 217 -       u32 *buf = (u32 *)&copy_page_array;
 218 +       u32 *buf = &__copy_page_start;
 219         struct uasm_label *l = labels;
 220         struct uasm_reloc *r = relocs;
 221         int i;
 222 @@ -596,21 +563,23 @@ void __cpuinit build_copy_page(void)
 223         uasm_i_jr(&buf, RA);
 224         uasm_i_nop(&buf);
 225
 226 -       BUG_ON(buf > copy_page_array + ARRAY_SIZE(copy_page_array));
 227 +       BUG_ON(buf > &__copy_page_end);
 228
 229         uasm_resolve_relocs(relocs, labels);
 230
 231         pr_debug("Synthesized copy page handler (%u instructions).\n",
 232 -                (u32)(buf - copy_page_array));
 233 +                (u32)(buf - &__copy_page_start));
 234
 235         pr_debug("\t.set push\n");
 236         pr_debug("\t.set noreorder\n");
 237 -       for (i = 0; i < (buf - copy_page_array); i++)
 238 -               pr_debug("\t.word 0x%08x\n", copy_page_array[i]);
 239 +       for (i = 0; i < (buf - &__copy_page_start); i++)
 240 +               pr_debug("\t.word 0x%08x\n", (&__copy_page_start)[i]);
 241         pr_debug("\t.set pop\n");
 242  }
 243
 244  #ifdef CONFIG_SIBYTE_DMA_PAGEOPS
 245 +extern void clear_page_cpu(void *page);
 246 +extern void copy_page_cpu(void *to, void *from);
 247
 248  /*
 249   * Pad descriptors to cacheline, since each is exclusively owned by a