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
  12
  13
  14#ifdef CONFIG_HWZOL
  15        .macro pop_zol
  16        mtusr   $r14, $LB
  17        mtusr   $r15, $LE
  18        mtusr   $r16, $LC
  19        .endm
  20#endif
  21
  22        .macro  restore_user_regs_first
  23        setgie.d
  24        isb
  25
  26        addi    $sp, $sp, FUCOP_CTL_OFFSET
  27
  28        lmw.adm $r12, [$sp], $r24, #0x0
  29        mtsr    $r12, $SP_USR
  30        mtsr    $r13, $IPC
  31#ifdef CONFIG_HWZOL
  32        pop_zol
  33#endif
  34        mtsr    $r19, $PSW
  35        mtsr    $r20, $IPSW
  36        mtsr    $r21, $P_IPSW
  37        mtsr    $r22, $P_IPC
  38        mtsr    $r23, $P_P0
  39        mtsr    $r24, $P_P1
  40        lmw.adm $sp, [$sp], $sp, #0xe
  41        .endm
  42
  43        .macro  restore_user_regs_last
  44        pop     $p0
  45        cmovn   $sp, $p0, $p0
  46
  47        iret
  48        nop
  49
  50        .endm
  51
  52        .macro  restore_user_regs
  53        restore_user_regs_first
  54        lmw.adm $r0, [$sp], $r25, #0x0
  55        addi    $sp, $sp, OSP_OFFSET
  56        restore_user_regs_last
  57        .endm
  58
  59        .macro  fast_restore_user_regs
  60        restore_user_regs_first
  61        lmw.adm $r1, [$sp], $r25, #0x0
  62        addi    $sp, $sp, OSP_OFFSET-4
  63        restore_user_regs_last
  64        .endm
  65
  66#ifdef CONFIG_PREEMPT
  67        .macro  preempt_stop
  68        .endm
  69#else
  70        .macro  preempt_stop
  71        setgie.d
  72        isb
  73        .endm
  74#define resume_kernel   no_work_pending
  75#endif
  76
  77ENTRY(ret_from_exception)
  78        preempt_stop
  79ENTRY(ret_from_intr)
  80
  81/*
  82 * judge Kernel or user mode
  83 *
  84 */
  85        lwi     $p0, [$sp+(#IPSW_OFFSET)]       ! Check if in nested interrupt
  86        andi    $p0, $p0, #PSW_mskINTL
  87        bnez    $p0, resume_kernel              ! done with iret
  88        j       resume_userspace
  89
  90
  91/*
  92 * This is the fast syscall return path.  We do as little as
  93 * possible here, and this includes saving $r0 back into the SVC
  94 * stack.
  95 * fixed: tsk - $r25, syscall # - $r7, syscall table pointer - $r8
  96 */
  97ENTRY(ret_fast_syscall)
  98        gie_disable
  99        lwi     $r1, [tsk+#TSK_TI_FLAGS]
 100        andi    $p1, $r1, #_TIF_WORK_MASK
 101        bnez    $p1, fast_work_pending
 102        fast_restore_user_regs                  ! iret
 103
 104/*
 105 * Ok, we need to do extra processing,
 106 * enter the slow path returning from syscall, while pending work.
 107 */
 108fast_work_pending:
 109        swi     $r0, [$sp+(#R0_OFFSET)]         ! what is different from ret_from_exception
 110work_pending:
 111        andi    $p1, $r1, #_TIF_NEED_RESCHED
 112        bnez    $p1, work_resched
 113
 114        andi    $p1, $r1, #_TIF_SIGPENDING|#_TIF_NOTIFY_RESUME
 115        beqz    $p1, no_work_pending
 116
 117        move    $r0, $sp                        ! 'regs'
 118        gie_enable
 119        bal     do_notify_resume
 120        b       ret_slow_syscall
 121work_resched:
 122        bal     schedule                        ! path, return to user mode
 123
 124/*
 125 * "slow" syscall return path.
 126 */
 127ENTRY(resume_userspace)
 128ENTRY(ret_slow_syscall)
 129        gie_disable
 130        lwi     $p0, [$sp+(#IPSW_OFFSET)]       ! Check if in nested interrupt
 131        andi    $p0, $p0, #PSW_mskINTL
 132        bnez    $p0, no_work_pending            ! done with iret
 133        lwi     $r1, [tsk+#TSK_TI_FLAGS]
 134        andi    $p1, $r1, #_TIF_WORK_MASK
 135        bnez    $p1, work_pending               ! handle work_resched, sig_pend
 136
 137no_work_pending:
 138#ifdef CONFIG_TRACE_IRQFLAGS
 139        lwi     $p0, [$sp+(#IPSW_OFFSET)]
 140        andi    $p0, $p0, #0x1
 141        la      $r10, trace_hardirqs_off
 142        la      $r9, trace_hardirqs_on
 143        cmovz   $r9, $p0, $r10
 144        jral    $r9
 145#endif
 146        restore_user_regs                       ! return from iret
 147
 148
 149/*
 150 * preemptive kernel
 151 */
 152#ifdef CONFIG_PREEMPT
 153resume_kernel:
 154        gie_disable
 155        lwi     $t0, [tsk+#TSK_TI_PREEMPT]
 156        bnez    $t0, no_work_pending
 157need_resched:
 158        lwi     $t0, [tsk+#TSK_TI_FLAGS]
 159        andi    $p1, $t0, #_TIF_NEED_RESCHED
 160        beqz    $p1, no_work_pending
 161
 162        lwi     $t0, [$sp+(#IPSW_OFFSET)]       ! Interrupts off?
 163        andi    $t0, $t0, #1
 164        beqz    $t0, no_work_pending
 165
 166        jal     preempt_schedule_irq
 167        b       need_resched
 168#endif
 169
 170/*
 171 * This is how we return from a fork.
 172 */
 173ENTRY(ret_from_fork)
 174        bal     schedule_tail
 175        beqz    $r6, 1f                         ! r6 stores fn for kernel thread
 176        move    $r0, $r7                        ! prepare kernel thread arg
 177        jral    $r6
 1781:
 179        lwi     $r1, [tsk+#TSK_TI_FLAGS]                ! check for syscall tracing
 180        andi    $p1, $r1, #_TIF_WORK_SYSCALL_LEAVE      ! are we tracing syscalls?
 181        beqz    $p1, ret_slow_syscall
 182        move    $r0, $sp
 183        bal     syscall_trace_leave
 184        b       ret_slow_syscall
 185