LXR linux/arch/nds32/kernel/ex-exit.S

   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4#include <linux/linkage.h>
   5#include <asm/unistd.h>
   6#include <asm/assembler.h>
   7#include <asm/nds32.h>
   8#include <asm/asm-offsets.h>
   9#include <asm/thread_info.h>
  10#include <asm/current.h>
  11#include <asm/fpu.h>
  12
  13
  14
  15#ifdef CONFIG_HWZOL
  16        .macro pop_zol
  17        mtusr   $r14, $LB
  18        mtusr   $r15, $LE
  19        mtusr   $r16, $LC
  20        .endm
  21#endif
  22
  23        .macro  restore_user_regs_first
  24        setgie.d
  25        isb
  26#if defined(CONFIG_FPU)
  27        addi    $sp, $sp, OSP_OFFSET
  28        lmw.adm $r12, [$sp], $r25, #0x0
  29        sethi   $p0, hi20(has_fpu)
  30        lbsi    $p0, [$p0+lo12(has_fpu)]
  31        beqz    $p0, 2f
  32        mtsr    $r25, $FUCOP_CTL
  332:
  34#else
  35        addi    $sp, $sp, FUCOP_CTL_OFFSET
  36        lmw.adm $r12, [$sp], $r24, #0x0
  37#endif
  38        mtsr    $r12, $SP_USR
  39        mtsr    $r13, $IPC
  40#ifdef CONFIG_HWZOL
  41        pop_zol
  42#endif
  43        mtsr    $r19, $PSW
  44        mtsr    $r20, $IPSW
  45        mtsr    $r21, $P_IPSW
  46        mtsr    $r22, $P_IPC
  47        mtsr    $r23, $P_P0
  48        mtsr    $r24, $P_P1
  49        lmw.adm $sp, [$sp], $sp, #0xe
  50        .endm
  51
  52        .macro  restore_user_regs_last
  53        pop     $p0
  54        cmovn   $sp, $p0, $p0
  55
  56        iret
  57        nop
  58
  59        .endm
  60
  61        .macro  restore_user_regs
  62        restore_user_regs_first
  63        lmw.adm $r0, [$sp], $r25, #0x0
  64        addi    $sp, $sp, OSP_OFFSET
  65        restore_user_regs_last
  66        .endm
  67
  68        .macro  fast_restore_user_regs
  69        restore_user_regs_first
  70        lmw.adm $r1, [$sp], $r25, #0x0
  71        addi    $sp, $sp, OSP_OFFSET-4
  72        restore_user_regs_last
  73        .endm
  74
  75#ifdef CONFIG_PREEMPTION
  76        .macro  preempt_stop
  77        .endm
  78#else
  79        .macro  preempt_stop
  80        setgie.d
  81        isb
  82        .endm
  83#define resume_kernel   no_work_pending
  84#endif
  85
  86ENTRY(ret_from_exception)
  87        preempt_stop
  88ENTRY(ret_from_intr)
  89
  90/*
  91 * judge Kernel or user mode
  92 *
  93 */
  94        lwi     $p0, [$sp+(#IPSW_OFFSET)]       ! Check if in nested interrupt
  95        andi    $p0, $p0, #PSW_mskINTL
  96        bnez    $p0, resume_kernel              ! done with iret
  97        j       resume_userspace
  98
  99
 100/*
 101 * This is the fast syscall return path.  We do as little as
 102 * possible here, and this includes saving $r0 back into the SVC
 103 * stack.
 104 * fixed: tsk - $r25, syscall # - $r7, syscall table pointer - $r8
 105 */
 106ENTRY(ret_fast_syscall)
 107        gie_disable
 108        lwi     $r1, [tsk+#TSK_TI_FLAGS]
 109        andi    $p1, $r1, #_TIF_WORK_MASK
 110        bnez    $p1, fast_work_pending
 111        fast_restore_user_regs                  ! iret
 112
 113/*
 114 * Ok, we need to do extra processing,
 115 * enter the slow path returning from syscall, while pending work.
 116 */
 117fast_work_pending:
 118        swi     $r0, [$sp+(#R0_OFFSET)]         ! what is different from ret_from_exception
 119work_pending:
 120        andi    $p1, $r1, #_TIF_NEED_RESCHED
 121        bnez    $p1, work_resched
 122
 123        andi    $p1, $r1, #_TIF_SIGPENDING|#_TIF_NOTIFY_RESUME
 124        beqz    $p1, no_work_pending
 125
 126        move    $r0, $sp                        ! 'regs'
 127        gie_enable
 128        bal     do_notify_resume
 129        b       ret_slow_syscall
 130work_resched:
 131        bal     schedule                        ! path, return to user mode
 132
 133/*
 134 * "slow" syscall return path.
 135 */
 136ENTRY(resume_userspace)
 137ENTRY(ret_slow_syscall)
 138        gie_disable
 139        lwi     $p0, [$sp+(#IPSW_OFFSET)]       ! Check if in nested interrupt
 140        andi    $p0, $p0, #PSW_mskINTL
 141        bnez    $p0, no_work_pending            ! done with iret
 142        lwi     $r1, [tsk+#TSK_TI_FLAGS]
 143        andi    $p1, $r1, #_TIF_WORK_MASK
 144        bnez    $p1, work_pending               ! handle work_resched, sig_pend
 145
 146no_work_pending:
 147#ifdef CONFIG_TRACE_IRQFLAGS
 148        lwi     $p0, [$sp+(#IPSW_OFFSET)]
 149        andi    $p0, $p0, #0x1
 150        la      $r10, __trace_hardirqs_off
 151        la      $r9, __trace_hardirqs_on
 152        cmovz   $r9, $p0, $r10
 153        jral    $r9
 154#endif
 155        restore_user_regs                       ! return from iret
 156
 157
 158/*
 159 * preemptive kernel
 160 */
 161#ifdef CONFIG_PREEMPTION
 162resume_kernel:
 163        gie_disable
 164        lwi     $t0, [tsk+#TSK_TI_PREEMPT]
 165        bnez    $t0, no_work_pending
 166
 167        lwi     $t0, [tsk+#TSK_TI_FLAGS]
 168        andi    $p1, $t0, #_TIF_NEED_RESCHED
 169        beqz    $p1, no_work_pending
 170
 171        lwi     $t0, [$sp+(#IPSW_OFFSET)]       ! Interrupts off?
 172        andi    $t0, $t0, #1
 173        beqz    $t0, no_work_pending
 174
 175        jal     preempt_schedule_irq
 176        b       no_work_pending
 177#endif
 178
 179/*
 180 * This is how we return from a fork.
 181 */
 182ENTRY(ret_from_fork)
 183        bal     schedule_tail
 184        beqz    $r6, 1f                         ! r6 stores fn for kernel thread
 185        move    $r0, $r7                        ! prepare kernel thread arg
 186        jral    $r6
 1871:
 188        lwi     $r1, [tsk+#TSK_TI_FLAGS]                ! check for syscall tracing
 189        andi    $p1, $r1, #_TIF_WORK_SYSCALL_LEAVE      ! are we tracing syscalls?
 190        beqz    $p1, ret_slow_syscall
 191        move    $r0, $sp
 192        bal     syscall_trace_leave
 193        b       ret_slow_syscall
 194