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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/linkage.h>
#include <asm/unistd.h>
#include <asm/assembler.h>
#include <asm/nds32.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/current.h>
#ifdef CONFIG_HWZOL
.macro pop_zol
mtusr $r14, $LB
mtusr $r15, $LE
mtusr $r16, $LC
.endm
#endif
.macro restore_user_regs_first
setgie.d
isb
addi $sp, $sp, FUCOP_CTL_OFFSET
lmw.adm $r12, [$sp], $r24, #0x0
mtsr $r12, $SP_USR
mtsr $r13, $IPC
#ifdef CONFIG_HWZOL
pop_zol
#endif
mtsr $r19, $PSW
mtsr $r20, $IPSW
mtsr $r21, $P_IPSW
mtsr $r22, $P_IPC
mtsr $r23, $P_P0
mtsr $r24, $P_P1
lmw.adm $sp, [$sp], $sp, #0xe
.endm
.macro restore_user_regs_last
pop $p0
cmovn $sp, $p0, $p0
iret
nop
.endm
.macro restore_user_regs
restore_user_regs_first
lmw.adm $r0, [$sp], $r25, #0x0
addi $sp, $sp, OSP_OFFSET
restore_user_regs_last
.endm
.macro fast_restore_user_regs
restore_user_regs_first
lmw.adm $r1, [$sp], $r25, #0x0
addi $sp, $sp, OSP_OFFSET-4
restore_user_regs_last
.endm
#ifdef CONFIG_PREEMPT
.macro preempt_stop
.endm
#else
.macro preempt_stop
setgie.d
isb
.endm
#define resume_kernel no_work_pending
#endif
ENTRY(ret_from_exception)
preempt_stop
ENTRY(ret_from_intr)
/*
* judge Kernel or user mode
*
*/
lwi $p0, [$sp+(#IPSW_OFFSET)] ! Check if in nested interrupt
andi $p0, $p0, #PSW_mskINTL
bnez $p0, resume_kernel ! done with iret
j resume_userspace
/*
* This is the fast syscall return path. We do as little as
* possible here, and this includes saving $r0 back into the SVC
* stack.
* fixed: tsk - $r25, syscall # - $r7, syscall table pointer - $r8
*/
ENTRY(ret_fast_syscall)
gie_disable
lwi $r1, [tsk+#TSK_TI_FLAGS]
andi $p1, $r1, #_TIF_WORK_MASK
bnez $p1, fast_work_pending
fast_restore_user_regs ! iret
/*
* Ok, we need to do extra processing,
* enter the slow path returning from syscall, while pending work.
*/
fast_work_pending:
swi $r0, [$sp+(#R0_OFFSET)] ! what is different from ret_from_exception
work_pending:
andi $p1, $r1, #_TIF_NEED_RESCHED
bnez $p1, work_resched
andi $p1, $r1, #_TIF_SIGPENDING|#_TIF_NOTIFY_RESUME
beqz $p1, no_work_pending
move $r0, $sp ! 'regs'
gie_enable
bal do_notify_resume
b ret_slow_syscall
work_resched:
bal schedule ! path, return to user mode
/*
* "slow" syscall return path.
*/
ENTRY(resume_userspace)
ENTRY(ret_slow_syscall)
gie_disable
lwi $p0, [$sp+(#IPSW_OFFSET)] ! Check if in nested interrupt
andi $p0, $p0, #PSW_mskINTL
bnez $p0, no_work_pending ! done with iret
lwi $r1, [tsk+#TSK_TI_FLAGS]
andi $p1, $r1, #_TIF_WORK_MASK
bnez $p1, work_pending ! handle work_resched, sig_pend
no_work_pending:
#ifdef CONFIG_TRACE_IRQFLAGS
lwi $p0, [$sp+(#IPSW_OFFSET)]
andi $p0, $p0, #0x1
la $r10, __trace_hardirqs_off
la $r9, __trace_hardirqs_on
cmovz $r9, $p0, $r10
jral $r9
#endif
restore_user_regs ! return from iret
/*
* preemptive kernel
*/
#ifdef CONFIG_PREEMPT
resume_kernel:
gie_disable
lwi $t0, [tsk+#TSK_TI_PREEMPT]
bnez $t0, no_work_pending
need_resched:
lwi $t0, [tsk+#TSK_TI_FLAGS]
andi $p1, $t0, #_TIF_NEED_RESCHED
beqz $p1, no_work_pending
lwi $t0, [$sp+(#IPSW_OFFSET)] ! Interrupts off?
andi $t0, $t0, #1
beqz $t0, no_work_pending
jal preempt_schedule_irq
b need_resched
#endif
/*
* This is how we return from a fork.
*/
ENTRY(ret_from_fork)
bal schedule_tail
beqz $r6, 1f ! r6 stores fn for kernel thread
move $r0, $r7 ! prepare kernel thread arg
jral $r6
1:
lwi $r1, [tsk+#TSK_TI_FLAGS] ! check for syscall tracing
andi $p1, $r1, #_TIF_WORK_SYSCALL_LEAVE ! are we tracing syscalls?
beqz $p1, ret_slow_syscall
move $r0, $sp
bal syscall_trace_leave
b ret_slow_syscall
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