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 #ifndef CONFIG_CPU_MIPSR2
  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 #if   defined(CONFIG_CPU_MIPSR2)
  46         /* see irqflags.h for inline function */
  47 #else
  48         "       mfc0    $1,$12                                          \n"
  49         "       ori     $1,0x1f                                         \n"
  50         "       xori    $1,0x1f                                         \n"
  51         "       .set    noreorder                                       \n"
  52         "       mtc0    $1,$12                                          \n"
  53 #endif
  54         "       " __stringify(__irq_disable_hazard) "                   \n"
  55         "       .set    pop                                             \n"
  56         : /* no outputs */
  57         : /* no inputs */
  58         : "memory");
  59
  60         preempt_enable();
  61 }
  62 EXPORT_SYMBOL(arch_local_irq_disable);
  63
  64
  65 notrace unsigned long arch_local_irq_save(void)
  66 {
  67         unsigned long flags;
  68
  69         preempt_disable();
  70
  71         __asm__ __volatile__(
  72         "       .set    push                                            \n"
  73         "       .set    reorder                                         \n"
  74         "       .set    noat                                            \n"
  75 #if   defined(CONFIG_CPU_MIPSR2)
  76         /* see irqflags.h for inline function */
  77 #else
  78         "       mfc0    %[flags], $12                                   \n"
  79         "       ori     $1, %[flags], 0x1f                              \n"
  80         "       xori    $1, 0x1f                                        \n"
  81         "       .set    noreorder                                       \n"
  82         "       mtc0    $1, $12                                         \n"
  83 #endif
  84         "       " __stringify(__irq_disable_hazard) "                   \n"
  85         "       .set    pop                                             \n"
  86         : [flags] "=r" (flags)
  87         : /* no inputs */
  88         : "memory");
  89
  90         preempt_enable();
  91
  92         return flags;
  93 }
  94 EXPORT_SYMBOL(arch_local_irq_save);
  95
  96 notrace void arch_local_irq_restore(unsigned long flags)
  97 {
  98         unsigned long __tmp1;
  99
 100         preempt_disable();
 101
 102         __asm__ __volatile__(
 103         "       .set    push                                            \n"
 104         "       .set    noreorder                                       \n"
 105         "       .set    noat                                            \n"
 106 #if   defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
 107         /* see irqflags.h for inline function */
 108 #elif defined(CONFIG_CPU_MIPSR2)
 109         /* see irqflags.h for inline function */
 110 #else
 111         "       mfc0    $1, $12                                         \n"
 112         "       andi    %[flags], 1                                     \n"
 113         "       ori     $1, 0x1f                                        \n"
 114         "       xori    $1, 0x1f                                        \n"
 115         "       or      %[flags], $1                                    \n"
 116         "       mtc0    %[flags], $12                                   \n"
 117 #endif
 118         "       " __stringify(__irq_disable_hazard) "                   \n"
 119         "       .set    pop                                             \n"
 120         : [flags] "=r" (__tmp1)
 121         : "0" (flags)
 122         : "memory");
 123
 124         preempt_enable();
 125 }
 126 EXPORT_SYMBOL(arch_local_irq_restore);
 127
 128
 129 notrace void __arch_local_irq_restore(unsigned long flags)
 130 {
 131         unsigned long __tmp1;
 132
 133         preempt_disable();
 134
 135         __asm__ __volatile__(
 136         "       .set    push                                            \n"
 137         "       .set    noreorder                                       \n"
 138         "       .set    noat                                            \n"
 139 #if   defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
 140         /* see irqflags.h for inline function */
 141 #elif defined(CONFIG_CPU_MIPSR2)
 142         /* see irqflags.h for inline function */
 143 #else
 144         "       mfc0    $1, $12                                         \n"
 145         "       andi    %[flags], 1                                     \n"
 146         "       ori     $1, 0x1f                                        \n"
 147         "       xori    $1, 0x1f                                        \n"
 148         "       or      %[flags], $1                                    \n"
 149         "       mtc0    %[flags], $12                                   \n"
 150 #endif
 151         "       " __stringify(__irq_disable_hazard) "                   \n"
 152         "       .set    pop                                             \n"
 153         : [flags] "=r" (__tmp1)
 154         : "0" (flags)
 155         : "memory");
 156
 157         preempt_enable();
 158 }
 159 EXPORT_SYMBOL(__arch_local_irq_restore);
 160
 161 #endif /* !CONFIG_CPU_MIPSR2 */