arch/mips/kernel/entry.S

   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 - 2000, 2001, 2003 Ralf Baechle
   7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   8  * Copyright (C) 2001 MIPS Technologies, Inc.
   9  */
  10 #include <linux/config.h>
  11
  12 #include <asm/asm.h>
  13 #include <asm/asmmacro.h>
  14 #include <asm/regdef.h>
  15 #include <asm/mipsregs.h>
  16 #include <asm/stackframe.h>
  17 #include <asm/isadep.h>
  18 #include <asm/thread_info.h>
  19 #include <asm/war.h>
  20
  21 #ifdef CONFIG_PREEMPT
  22         .macro  preempt_stop
  23         .endm
  24 #else
  25         .macro  preempt_stop
  26         local_irq_disable
  27         .endm
  28 #define resume_kernel   restore_all
  29 #endif
  30
  31         .text
  32         .align  5
  33 FEXPORT(ret_from_exception)
  34         preempt_stop
  35 FEXPORT(ret_from_irq)
  36         LONG_L  t0, PT_STATUS(sp)               # returning to kernel mode?
  37         andi    t0, t0, KU_USER
  38         beqz    t0, resume_kernel
  39
  40 resume_userspace:
  41         local_irq_disable               # make sure we dont miss an
  42                                         # interrupt setting need_resched
  43                                         # between sampling and return
  44         LONG_L  a2, TI_FLAGS($28)       # current->work
  45         andi    t0, a2, _TIF_WORK_MASK  # (ignoring syscall_trace)
  46         bnez    t0, work_pending
  47         j       restore_all
  48
  49 #ifdef CONFIG_PREEMPT
  50 resume_kernel:
  51         local_irq_disable
  52         lw      t0, TI_PRE_COUNT($28)
  53         bnez    t0, restore_all
  54 need_resched:
  55         LONG_L  t0, TI_FLAGS($28)
  56         andi    t1, t0, _TIF_NEED_RESCHED
  57         beqz    t1, restore_all
  58         LONG_L  t0, PT_STATUS(sp)               # Interrupts off?
  59         andi    t0, 1
  60         beqz    t0, restore_all
  61         jal     preempt_schedule_irq
  62         b       need_resched
  63 #endif
  64
  65 FEXPORT(ret_from_fork)
  66         jal     schedule_tail           # a0 = task_t *prev
  67
  68 FEXPORT(syscall_exit)
  69         local_irq_disable               # make sure need_resched and
  70                                         # signals dont change between
  71                                         # sampling and return
  72         LONG_L  a2, TI_FLAGS($28)       # current->work
  73         li      t0, _TIF_ALLWORK_MASK
  74         and     t0, a2, t0
  75         bnez    t0, syscall_exit_work
  76
  77 FEXPORT(restore_all)                    # restore full frame
  78         .set    noat
  79         RESTORE_TEMP
  80         RESTORE_AT
  81         RESTORE_STATIC
  82 FEXPORT(restore_partial)                # restore partial frame
  83         RESTORE_SOME
  84         RESTORE_SP_AND_RET
  85         .set    at
  86
  87 work_pending:
  88         andi    t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
  89         beqz    t0, work_notifysig
  90 work_resched:
  91         jal     schedule
  92
  93         local_irq_disable               # make sure need_resched and
  94                                         # signals dont change between
  95                                         # sampling and return
  96         LONG_L  a2, TI_FLAGS($28)
  97         andi    t0, a2, _TIF_WORK_MASK  # is there any work to be done
  98                                         # other than syscall tracing?
  99         beqz    t0, restore_all
 100         andi    t0, a2, _TIF_NEED_RESCHED
 101         bnez    t0, work_resched
 102
 103 work_notifysig:                         # deal with pending signals and
 104                                         # notify-resume requests
 105         move    a0, sp
 106         li      a1, 0
 107         jal     do_notify_resume        # a2 already loaded
 108         j       restore_all
 109
 110 FEXPORT(syscall_exit_work_partial)
 111         SAVE_STATIC
 112 syscall_exit_work:
 113         li      t0, _TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT
 114         and     t0, a2                  # a2 is preloaded with TI_FLAGS
 115         beqz    t0, work_pending        # trace bit set?
 116         local_irq_enable                # could let do_syscall_trace()
 117                                         # call schedule() instead
 118         move    a0, sp
 119         li      a1, 1
 120         jal     do_syscall_trace
 121         b       resume_userspace
 122
 123 /*
 124  * Common spurious interrupt handler.
 125  */
 126 LEAF(spurious_interrupt)
 127         /*
 128          * Someone tried to fool us by sending an interrupt but we
 129          * couldn't find a cause for it.
 130          */
 131         PTR_LA  t1, irq_err_count
 132 #ifdef CONFIG_SMP
 133 1:      ll      t0, (t1)
 134         addiu   t0, 1
 135         sc      t0, (t1)
 136 #if R10000_LLSC_WAR
 137         beqzl   t0, 1b
 138 #else
 139         beqz    t0, 1b
 140 #endif
 141 #else
 142         lw      t0, (t1)
 143         addiu   t0, 1
 144         sw      t0, (t1)
 145 #endif
 146         j       ret_from_irq
 147         END(spurious_interrupt)