arch/mips/lib/mips-atomic.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003 by Ralf Baechle
   7  * Copyright (C) 1996 by Paul M. Antoine
   8  * Copyright (C) 1999 Silicon Graphics
   9  * Copyright (C) 2000 MIPS Technologies, Inc.
  10  */
  11 #include <asm/irqflags.h>
  12 #include <asm/hazards.h>
  13 #include <linux/compiler.h>
  14 #include <linux/preempt.h>
  15 #include <linux/export.h>
  16 #include <linux/stringify.h>
  17
  18 #if !defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_MIPS_MT_SMTC)
  19
  20 /*
  21  * For cli() we have to insert nops to make sure that the new value
  22  * has actually arrived in the status register before the end of this
  23  * macro.
  24  * R4000/R4400 need three nops, the R4600 two nops and the R10000 needs
  25  * no nops at all.
  26  */
  27 /*
  28  * For TX49, operating only IE bit is not enough.
  29  *
  30  * If mfc0 $12 follows store and the mfc0 is last instruction of a
  31  * page and fetching the next instruction causes TLB miss, the result
  32  * of the mfc0 might wrongly contain EXL bit.
  33  *
  34  * ERT-TX49H2-027, ERT-TX49H3-012, ERT-TX49HL3-006, ERT-TX49H4-008
  35  *
  36  * Workaround: mask EXL bit of the result or place a nop before mfc0.
  37  */
  38 notrace void arch_local_irq_disable(void)
  39 {
  40         preempt_disable();
  41
  42         __asm__ __volatile__(
  43         "       .set    push                                            \n"
  44         "       .set    noat                                            \n"
  45 #ifdef CONFIG_MIPS_MT_SMTC
  46         "       mfc0    $1, $2, 1                                       \n"
  47         "       ori     $1, 0x400                                       \n"
  48         "       .set    noreorder                                       \n"
  49         "       mtc0    $1, $2, 1                                       \n"
  50 #elif defined(CONFIG_CPU_MIPSR2)
  51         /* see irqflags.h for inline function */
  52 #else
  53         "       mfc0    $1,$12                                          \n"
  54         "       ori     $1,0x1f                                         \n"
  55         "       xori    $1,0x1f                                         \n"
  56         "       .set    noreorder                                       \n"
  57         "       mtc0    $1,$12                                          \n"
  58 #endif
  59         "       " __stringify(__irq_disable_hazard) "                   \n"
  60         "       .set    pop                                             \n"
  61         : /* no outputs */
  62         : /* no inputs */
  63         : "memory");
  64
  65         preempt_enable();
  66 }
  67 EXPORT_SYMBOL(arch_local_irq_disable);
  68
  69
  70 notrace unsigned long arch_local_irq_save(void)
  71 {
  72         unsigned long flags;
  73
  74         preempt_disable();
  75
  76         __asm__ __volatile__(
  77         "       .set    push                                            \n"
  78         "       .set    reorder                                         \n"
  79         "       .set    noat                                            \n"
  80 #ifdef CONFIG_MIPS_MT_SMTC
  81         "       mfc0    %[flags], $2, 1                         \n"
  82         "       ori     $1, %[flags], 0x400                             \n"
  83         "       .set    noreorder                                       \n"
  84         "       mtc0    $1, $2, 1                                       \n"
  85         "       andi    %[flags], %[flags], 0x400                       \n"
  86 #elif defined(CONFIG_CPU_MIPSR2)
  87         /* see irqflags.h for inline function */
  88 #else
  89         "       mfc0    %[flags], $12                                   \n"
  90         "       ori     $1, %[flags], 0x1f                              \n"
  91         "       xori    $1, 0x1f                                        \n"
  92         "       .set    noreorder                                       \n"
  93         "       mtc0    $1, $12                                         \n"
  94 #endif
  95         "       " __stringify(__irq_disable_hazard) "                   \n"
  96         "       .set    pop                                             \n"
  97         : [flags] "=r" (flags)
  98         : /* no inputs */
  99         : "memory");
 100
 101         preempt_enable();
 102
 103         return flags;
 104 }
 105 EXPORT_SYMBOL(arch_local_irq_save);
 106
 107 notrace void arch_local_irq_restore(unsigned long flags)
 108 {
 109         unsigned long __tmp1;
 110
 111 #ifdef CONFIG_MIPS_MT_SMTC
 112         /*
 113          * SMTC kernel needs to do a software replay of queued
 114          * IPIs, at the cost of branch and call overhead on each
 115          * local_irq_restore()
 116          */
 117         if (unlikely(!(flags & 0x0400)))
 118                 smtc_ipi_replay();
 119 #endif
 120         preempt_disable();
 121
 122         __asm__ __volatile__(
 123         "       .set    push                                            \n"
 124         "       .set    noreorder                                       \n"
 125         "       .set    noat                                            \n"
 126 #ifdef CONFIG_MIPS_MT_SMTC
 127         "       mfc0    $1, $2, 1                                       \n"
 128         "       andi    %[flags], 0x400                                 \n"
 129         "       ori     $1, 0x400                                       \n"
 130         "       xori    $1, 0x400                                       \n"
 131         "       or      %[flags], $1                                    \n"
 132         "       mtc0    %[flags], $2, 1                                 \n"
 133 #elif defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
 134         /* see irqflags.h for inline function */
 135 #elif defined(CONFIG_CPU_MIPSR2)
 136         /* see irqflags.h for inline function */
 137 #else
 138         "       mfc0    $1, $12                                         \n"
 139         "       andi    %[flags], 1                                     \n"
 140         "       ori     $1, 0x1f                                        \n"
 141         "       xori    $1, 0x1f                                        \n"
 142         "       or      %[flags], $1                                    \n"
 143         "       mtc0    %[flags], $12                                   \n"
 144 #endif
 145         "       " __stringify(__irq_disable_hazard) "                   \n"
 146         "       .set    pop                                             \n"
 147         : [flags] "=r" (__tmp1)
 148         : "0" (flags)
 149         : "memory");
 150
 151         preempt_enable();
 152 }
 153 EXPORT_SYMBOL(arch_local_irq_restore);
 154
 155
 156 notrace void __arch_local_irq_restore(unsigned long flags)
 157 {
 158         unsigned long __tmp1;
 159
 160         preempt_disable();
 161
 162         __asm__ __volatile__(
 163         "       .set    push                                            \n"
 164         "       .set    noreorder                                       \n"
 165         "       .set    noat                                            \n"
 166 #ifdef CONFIG_MIPS_MT_SMTC
 167         "       mfc0    $1, $2, 1                                       \n"
 168         "       andi    %[flags], 0x400                                 \n"
 169         "       ori     $1, 0x400                                       \n"
 170         "       xori    $1, 0x400                                       \n"
 171         "       or      %[flags], $1                                    \n"
 172         "       mtc0    %[flags], $2, 1                                 \n"
 173 #elif defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
 174         /* see irqflags.h for inline function */
 175 #elif defined(CONFIG_CPU_MIPSR2)
 176         /* see irqflags.h for inline function */
 177 #else
 178         "       mfc0    $1, $12                                         \n"
 179         "       andi    %[flags], 1                                     \n"
 180         "       ori     $1, 0x1f                                        \n"
 181         "       xori    $1, 0x1f                                        \n"
 182         "       or      %[flags], $1                                    \n"
 183         "       mtc0    %[flags], $12                                   \n"
 184 #endif
 185         "       " __stringify(__irq_disable_hazard) "                   \n"
 186         "       .set    pop                                             \n"
 187         : [flags] "=r" (__tmp1)
 188         : "0" (flags)
 189         : "memory");
 190
 191         preempt_enable();
 192 }
 193 EXPORT_SYMBOL(__arch_local_irq_restore);
 194
 195 #endif /* !defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_MIPS_MT_SMTC) */