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_HAS_DIEI)
  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         "       mfc0    $1,$12                                          \n"
  46         "       ori     $1,0x1f                                         \n"
  47         "       xori    $1,0x1f                                         \n"
  48         "       .set    noreorder                                       \n"
  49         "       mtc0    $1,$12                                          \n"
  50         "       " __stringify(__irq_disable_hazard) "                   \n"
  51         "       .set    pop                                             \n"
  52         : /* no outputs */
  53         : /* no inputs */
  54         : "memory");
  55
  56         preempt_enable();
  57 }
  58 EXPORT_SYMBOL(arch_local_irq_disable);
  59
  60 notrace unsigned long arch_local_irq_save(void)
  61 {
  62         unsigned long flags;
  63
  64         preempt_disable();
  65
  66         __asm__ __volatile__(
  67         "       .set    push                                            \n"
  68         "       .set    reorder                                         \n"
  69         "       .set    noat                                            \n"
  70         "       mfc0    %[flags], $12                                   \n"
  71         "       ori     $1, %[flags], 0x1f                              \n"
  72         "       xori    $1, 0x1f                                        \n"
  73         "       .set    noreorder                                       \n"
  74         "       mtc0    $1, $12                                         \n"
  75         "       " __stringify(__irq_disable_hazard) "                   \n"
  76         "       .set    pop                                             \n"
  77         : [flags] "=r" (flags)
  78         : /* no inputs */
  79         : "memory");
  80
  81         preempt_enable();
  82
  83         return flags;
  84 }
  85 EXPORT_SYMBOL(arch_local_irq_save);
  86
  87 notrace void arch_local_irq_restore(unsigned long flags)
  88 {
  89         unsigned long __tmp1;
  90
  91         preempt_disable();
  92
  93         __asm__ __volatile__(
  94         "       .set    push                                            \n"
  95         "       .set    noreorder                                       \n"
  96         "       .set    noat                                            \n"
  97         "       mfc0    $1, $12                                         \n"
  98         "       andi    %[flags], 1                                     \n"
  99         "       ori     $1, 0x1f                                        \n"
 100         "       xori    $1, 0x1f                                        \n"
 101         "       or      %[flags], $1                                    \n"
 102         "       mtc0    %[flags], $12                                   \n"
 103         "       " __stringify(__irq_disable_hazard) "                   \n"
 104         "       .set    pop                                             \n"
 105         : [flags] "=r" (__tmp1)
 106         : "0" (flags)
 107         : "memory");
 108
 109         preempt_enable();
 110 }
 111 EXPORT_SYMBOL(arch_local_irq_restore);
 112
 113 #endif /* !CONFIG_CPU_HAS_DIEI */