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
  11 #include <asm/asm.h>
  12 #include <asm/asmmacro.h>
  13 #include <asm/regdef.h>
  14 #include <asm/mipsregs.h>
  15 #include <asm/stackframe.h>
  16 #include <asm/isadep.h>
  17 #include <asm/thread_info.h>
  18 #include <asm/war.h>
  19 #ifdef CONFIG_MIPS_MT_SMTC
  20 #include <asm/mipsmtregs.h>
  21 #endif
  22
  23 #ifndef CONFIG_PREEMPT
  24         .macro  preempt_stop
  25         local_irq_disable
  26         .endm
  27 #define resume_kernel   restore_all
  28 #endif
  29
  30         .text
  31         .align  5
  32 FEXPORT(ret_from_irq)
  33         LONG_S  s0, TI_REGS($28)
  34 #ifdef CONFIG_PREEMPT
  35 FEXPORT(ret_from_exception)
  36 #else
  37         b       _ret_from_irq
  38 FEXPORT(ret_from_exception)
  39         preempt_stop
  40 #endif
  41 FEXPORT(_ret_from_irq)
  42         LONG_L  t0, PT_STATUS(sp)               # returning to kernel mode?
  43         andi    t0, t0, KU_USER
  44         beqz    t0, resume_kernel
  45
  46 resume_userspace:
  47         local_irq_disable               # make sure we dont miss an
  48                                         # interrupt setting need_resched
  49                                         # between sampling and return
  50         LONG_L  a2, TI_FLAGS($28)       # current->work
  51         andi    t0, a2, _TIF_WORK_MASK  # (ignoring syscall_trace)
  52         bnez    t0, work_pending
  53         j       restore_all
  54
  55 #ifdef CONFIG_PREEMPT
  56 resume_kernel:
  57         local_irq_disable
  58         lw      t0, TI_PRE_COUNT($28)
  59         bnez    t0, restore_all
  60 need_resched:
  61         LONG_L  t0, TI_FLAGS($28)
  62         andi    t1, t0, _TIF_NEED_RESCHED
  63         beqz    t1, restore_all
  64         LONG_L  t0, PT_STATUS(sp)               # Interrupts off?
  65         andi    t0, 1
  66         beqz    t0, restore_all
  67         jal     preempt_schedule_irq
  68         b       need_resched
  69 #endif
  70
  71 FEXPORT(ret_from_fork)
  72         jal     schedule_tail           # a0 = struct task_struct *prev
  73
  74 FEXPORT(syscall_exit)
  75         local_irq_disable               # make sure need_resched and
  76                                         # signals dont change between
  77                                         # sampling and return
  78         LONG_L  a2, TI_FLAGS($28)       # current->work
  79         li      t0, _TIF_ALLWORK_MASK
  80         and     t0, a2, t0
  81         bnez    t0, syscall_exit_work
  82
  83 FEXPORT(restore_all)                    # restore full frame
  84 #ifdef CONFIG_MIPS_MT_SMTC
  85 /* Detect and execute deferred IPI "interrupts" */
  86         jal     deferred_smtc_ipi
  87 /* Re-arm any temporarily masked interrupts not explicitly "acked" */
  88         mfc0    v0, CP0_TCSTATUS
  89         ori     v1, v0, TCSTATUS_IXMT
  90         mtc0    v1, CP0_TCSTATUS
  91         andi    v0, TCSTATUS_IXMT
  92         _ehb
  93         mfc0    t0, CP0_TCCONTEXT
  94         DMT     9                               # dmt t1
  95         jal     mips_ihb
  96         mfc0    t2, CP0_STATUS
  97         andi    t3, t0, 0xff00
  98         or      t2, t2, t3
  99         mtc0    t2, CP0_STATUS
 100         _ehb
 101         andi    t1, t1, VPECONTROL_TE
 102         beqz    t1, 1f
 103         EMT
 104 1:
 105         mfc0    v1, CP0_TCSTATUS
 106         /* We set IXMT above, XOR should clear it here */
 107         xori    v1, v1, TCSTATUS_IXMT
 108         or      v1, v0, v1
 109         mtc0    v1, CP0_TCSTATUS
 110         _ehb
 111         xor     t0, t0, t3
 112         mtc0    t0, CP0_TCCONTEXT
 113 #endif /* CONFIG_MIPS_MT_SMTC */
 114         .set    noat
 115         RESTORE_TEMP
 116         RESTORE_AT
 117         RESTORE_STATIC
 118 FEXPORT(restore_partial)                # restore partial frame
 119 #ifdef CONFIG_TRACE_IRQFLAGS
 120         SAVE_STATIC
 121         SAVE_AT
 122         SAVE_TEMP
 123         LONG_L  v0, PT_STATUS(sp)
 124         and     v0, 1
 125         beqz    v0, 1f
 126         jal     trace_hardirqs_on
 127         b       2f
 128 1:      jal     trace_hardirqs_off
 129 2:
 130         RESTORE_TEMP
 131         RESTORE_AT
 132         RESTORE_STATIC
 133 #endif
 134         RESTORE_SOME
 135         RESTORE_SP_AND_RET
 136         .set    at
 137
 138 work_pending:
 139         andi    t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
 140         beqz    t0, work_notifysig
 141 work_resched:
 142         jal     schedule
 143
 144         local_irq_disable               # make sure need_resched and
 145                                         # signals dont change between
 146                                         # sampling and return
 147         LONG_L  a2, TI_FLAGS($28)
 148         andi    t0, a2, _TIF_WORK_MASK  # is there any work to be done
 149                                         # other than syscall tracing?
 150         beqz    t0, restore_all
 151         andi    t0, a2, _TIF_NEED_RESCHED
 152         bnez    t0, work_resched
 153
 154 work_notifysig:                         # deal with pending signals and
 155                                         # notify-resume requests
 156         move    a0, sp
 157         li      a1, 0
 158         jal     do_notify_resume        # a2 already loaded
 159         j       resume_userspace
 160
 161 FEXPORT(syscall_exit_work_partial)
 162         SAVE_STATIC
 163 syscall_exit_work:
 164         li      t0, _TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT
 165         and     t0, a2                  # a2 is preloaded with TI_FLAGS
 166         beqz    t0, work_pending        # trace bit set?
 167         local_irq_enable                # could let do_syscall_trace()
 168                                         # call schedule() instead
 169         move    a0, sp
 170         li      a1, 1
 171         jal     do_syscall_trace
 172         b       resume_userspace
 173
 174 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_MIPS_MT)
 175
 176 /*
 177  * MIPS32R2 Instruction Hazard Barrier - must be called
 178  *
 179  * For C code use the inline version named instruction_hazard().
 180  */
 181 LEAF(mips_ihb)
 182         .set    mips32r2
 183         jr.hb   ra
 184         nop
 185         END(mips_ihb)
 186
 187 #endif /* CONFIG_CPU_MIPSR2 or CONFIG_MIPS_MT */