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
  17 #if !defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_MIPS_MT_SMTC)
  18
  19 /*
  20  * For cli() we have to insert nops to make sure that the new value
  21  * has actually arrived in the status register before the end of this
  22  * macro.
  23  * R4000/R4400 need three nops, the R4600 two nops and the R10000 needs
  24  * no nops at all.
  25  */
  26 /*
  27  * For TX49, operating only IE bit is not enough.
  28  *
  29  * If mfc0 $12 follows store and the mfc0 is last instruction of a
  30  * page and fetching the next instruction causes TLB miss, the result
  31  * of the mfc0 might wrongly contain EXL bit.
  32  *
  33  * ERT-TX49H2-027, ERT-TX49H3-012, ERT-TX49HL3-006, ERT-TX49H4-008
  34  *
  35  * Workaround: mask EXL bit of the result or place a nop before mfc0.
  36  */
  37 __asm__(
  38         "       .macro  arch_local_irq_disable\n"
  39         "       .set    push                                            \n"
  40         "       .set    noat                                            \n"
  41 #ifdef CONFIG_MIPS_MT_SMTC
  42         "       mfc0    $1, $2, 1                                       \n"
  43         "       ori     $1, 0x400                                       \n"
  44         "       .set    noreorder                                       \n"
  45         "       mtc0    $1, $2, 1                                       \n"
  46 #elif defined(CONFIG_CPU_MIPSR2)
  47         /* see irqflags.h for inline function */
  48 #else
  49         "       mfc0    $1,$12                                          \n"
  50         "       ori     $1,0x1f                                         \n"
  51         "       xori    $1,0x1f                                         \n"
  52         "       .set    noreorder                                       \n"
  53         "       mtc0    $1,$12                                          \n"
  54 #endif
  55         "       irq_disable_hazard                                      \n"
  56         "       .set    pop                                             \n"
  57         "       .endm                                                   \n");
  58
  59 void arch_local_irq_disable(void)
  60 {
  61         preempt_disable();
  62         __asm__ __volatile__(
  63                 "arch_local_irq_disable"
  64                 : /* no outputs */
  65                 : /* no inputs */
  66                 : "memory");
  67         preempt_enable();
  68 }
  69 EXPORT_SYMBOL(arch_local_irq_disable);
  70
  71
  72 __asm__(
  73         "       .macro  arch_local_irq_save result                      \n"
  74         "       .set    push                                            \n"
  75         "       .set    reorder                                         \n"
  76         "       .set    noat                                            \n"
  77 #ifdef CONFIG_MIPS_MT_SMTC
  78         "       mfc0    \\result, $2, 1                                 \n"
  79         "       ori     $1, \\result, 0x400                             \n"
  80         "       .set    noreorder                                       \n"
  81         "       mtc0    $1, $2, 1                                       \n"
  82         "       andi    \\result, \\result, 0x400                       \n"
  83 #elif defined(CONFIG_CPU_MIPSR2)
  84         /* see irqflags.h for inline function */
  85 #else
  86         "       mfc0    \\result, $12                                   \n"
  87         "       ori     $1, \\result, 0x1f                              \n"
  88         "       xori    $1, 0x1f                                        \n"
  89         "       .set    noreorder                                       \n"
  90         "       mtc0    $1, $12                                         \n"
  91 #endif
  92         "       irq_disable_hazard                                      \n"
  93         "       .set    pop                                             \n"
  94         "       .endm                                                   \n");
  95
  96 unsigned long arch_local_irq_save(void)
  97 {
  98         unsigned long flags;
  99         preempt_disable();
 100         asm volatile("arch_local_irq_save\t%0"
 101                      : "=r" (flags)
 102                      : /* no inputs */
 103                      : "memory");
 104         preempt_enable();
 105         return flags;
 106 }
 107 EXPORT_SYMBOL(arch_local_irq_save);
 108
 109
 110 __asm__(
 111         "       .macro  arch_local_irq_restore flags                    \n"
 112         "       .set    push                                            \n"
 113         "       .set    noreorder                                       \n"
 114         "       .set    noat                                            \n"
 115 #ifdef CONFIG_MIPS_MT_SMTC
 116         "mfc0   $1, $2, 1                                               \n"
 117         "andi   \\flags, 0x400                                          \n"
 118         "ori    $1, 0x400                                               \n"
 119         "xori   $1, 0x400                                               \n"
 120         "or     \\flags, $1                                             \n"
 121         "mtc0   \\flags, $2, 1                                          \n"
 122 #elif defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
 123         /* see irqflags.h for inline function */
 124 #elif defined(CONFIG_CPU_MIPSR2)
 125         /* see irqflags.h for inline function */
 126 #else
 127         "       mfc0    $1, $12                                         \n"
 128         "       andi    \\flags, 1                                      \n"
 129         "       ori     $1, 0x1f                                        \n"
 130         "       xori    $1, 0x1f                                        \n"
 131         "       or      \\flags, $1                                     \n"
 132         "       mtc0    \\flags, $12                                    \n"
 133 #endif
 134         "       irq_disable_hazard                                      \n"
 135         "       .set    pop                                             \n"
 136         "       .endm                                                   \n");
 137
 138 void arch_local_irq_restore(unsigned long flags)
 139 {
 140         unsigned long __tmp1;
 141
 142 #ifdef CONFIG_MIPS_MT_SMTC
 143         /*
 144          * SMTC kernel needs to do a software replay of queued
 145          * IPIs, at the cost of branch and call overhead on each
 146          * local_irq_restore()
 147          */
 148         if (unlikely(!(flags & 0x0400)))
 149                 smtc_ipi_replay();
 150 #endif
 151         preempt_disable();
 152         __asm__ __volatile__(
 153                 "arch_local_irq_restore\t%0"
 154                 : "=r" (__tmp1)
 155                 : "0" (flags)
 156                 : "memory");
 157         preempt_enable();
 158 }
 159 EXPORT_SYMBOL(arch_local_irq_restore);
 160
 161
 162 void __arch_local_irq_restore(unsigned long flags)
 163 {
 164         unsigned long __tmp1;
 165
 166         preempt_disable();
 167         __asm__ __volatile__(
 168                 "arch_local_irq_restore\t%0"
 169                 : "=r" (__tmp1)
 170                 : "0" (flags)
 171                 : "memory");
 172         preempt_enable();
 173 }
 174 EXPORT_SYMBOL(__arch_local_irq_restore);
 175
 176 #endif /* !defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_MIPS_MT_SMTC) */