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/* SPDX-License-Identifier: GPL-2.0 */
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
#include <linux/linkage.h>
#include <abi/entry.h>
#include <abi/pgtable-bits.h>
#include <asm/errno.h>
#include <asm/setup.h>
#include <asm/unistd.h>
#include <asm/asm-offsets.h>
#include <linux/threads.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/thread_info.h>
#define PTE_INDX_MSK 0xffc
#define PTE_INDX_SHIFT 10
#define _PGDIR_SHIFT 22
.macro tlbop_begin name, val0, val1, val2
ENTRY(csky_\name)
mtcr a3, ss2
mtcr r6, ss3
mtcr a2, ss4
RD_PGDR r6
RD_MEH a3
#ifdef CONFIG_CPU_HAS_TLBI
tlbi.vaas a3
sync.is
btsti a3, 31
bf 1f
RD_PGDR_K r6
1:
#else
bgeni a2, 31
WR_MCIR a2
bgeni a2, 25
WR_MCIR a2
#endif
bclri r6, 0
lrw a2, PHYS_OFFSET
subu r6, a2
bseti r6, 31
mov a2, a3
lsri a2, _PGDIR_SHIFT
lsli a2, 2
addu r6, a2
ldw r6, (r6)
lrw a2, PHYS_OFFSET
subu r6, a2
bseti r6, 31
lsri a3, PTE_INDX_SHIFT
lrw a2, PTE_INDX_MSK
and a3, a2
addu r6, a3
ldw a3, (r6)
movi a2, (_PAGE_PRESENT | \val0)
and a3, a2
cmpne a3, a2
bt \name
/* First read/write the page, just update the flags */
ldw a3, (r6)
bgeni a2, PAGE_VALID_BIT
bseti a2, PAGE_ACCESSED_BIT
bseti a2, \val1
bseti a2, \val2
or a3, a2
stw a3, (r6)
/* Some cpu tlb-hardrefill bypass the cache */
#ifdef CONFIG_CPU_NEED_TLBSYNC
movi a2, 0x22
bseti a2, 6
mtcr r6, cr22
mtcr a2, cr17
sync
#endif
mfcr a3, ss2
mfcr r6, ss3
mfcr a2, ss4
rte
\name:
mfcr a3, ss2
mfcr r6, ss3
mfcr a2, ss4
SAVE_ALL EPC_KEEP
.endm
.macro tlbop_end is_write
RD_MEH a2
psrset ee, ie
mov a0, sp
movi a1, \is_write
jbsr do_page_fault
movi r11_sig, 0 /* r11 = 0, Not a syscall. */
jmpi ret_from_exception
.endm
.text
tlbop_begin tlbinvalidl, _PAGE_READ, PAGE_VALID_BIT, PAGE_ACCESSED_BIT
tlbop_end 0
tlbop_begin tlbinvalids, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
tlbop_end 1
tlbop_begin tlbmodified, _PAGE_WRITE, PAGE_DIRTY_BIT, PAGE_MODIFIED_BIT
#ifndef CONFIG_CPU_HAS_LDSTEX
jbsr csky_cmpxchg_fixup
#endif
tlbop_end 1
ENTRY(csky_systemcall)
SAVE_ALL EPC_INCREASE
psrset ee, ie
lrw r11, __NR_syscalls
cmphs syscallid, r11 /* Check nr of syscall */
bt ret_from_exception
lrw r13, sys_call_table
ixw r13, syscallid
ldw r11, (r13)
cmpnei r11, 0
bf ret_from_exception
mov r9, sp
bmaski r10, THREAD_SHIFT
andn r9, r10
ldw r8, (r9, TINFO_FLAGS)
btsti r8, TIF_SYSCALL_TRACE
bt 1f
#if defined(__CSKYABIV2__)
subi sp, 8
stw r5, (sp, 0x4)
stw r4, (sp, 0x0)
jsr r11 /* Do system call */
addi sp, 8
#else
jsr r11
#endif
stw a0, (sp, LSAVE_A0) /* Save return value */
jmpi ret_from_exception
1:
movi a0, 0 /* enter system call */
mov a1, sp /* sp = pt_regs pointer */
jbsr syscall_trace
/* Prepare args before do system call */
ldw a0, (sp, LSAVE_A0)
ldw a1, (sp, LSAVE_A1)
ldw a2, (sp, LSAVE_A2)
ldw a3, (sp, LSAVE_A3)
#if defined(__CSKYABIV2__)
subi sp, 8
stw r5, (sp, 0x4)
stw r4, (sp, 0x0)
#else
ldw r6, (sp, LSAVE_A4)
ldw r7, (sp, LSAVE_A5)
#endif
jsr r11 /* Do system call */
#if defined(__CSKYABIV2__)
addi sp, 8
#endif
stw a0, (sp, LSAVE_A0) /* Save return value */
movi a0, 1 /* leave system call */
mov a1, sp /* right now, sp --> pt_regs */
jbsr syscall_trace
br ret_from_exception
ENTRY(ret_from_kernel_thread)
jbsr schedule_tail
mov a0, r8
jsr r9
jbsr ret_from_exception
ENTRY(ret_from_fork)
jbsr schedule_tail
mov r9, sp
bmaski r10, THREAD_SHIFT
andn r9, r10
ldw r8, (r9, TINFO_FLAGS)
movi r11_sig, 1
btsti r8, TIF_SYSCALL_TRACE
bf 3f
movi a0, 1
mov a1, sp /* sp = pt_regs pointer */
jbsr syscall_trace
3:
jbsr ret_from_exception
ret_from_exception:
ld syscallid, (sp, LSAVE_PSR)
btsti syscallid, 31
bt 1f
/*
* Load address of current->thread_info, Then get address of task_struct
* Get task_needreshed in task_struct
*/
mov r9, sp
bmaski r10, THREAD_SHIFT
andn r9, r10
resume_userspace:
ldw r8, (r9, TINFO_FLAGS)
andi r8, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED)
cmpnei r8, 0
bt exit_work
1: RESTORE_ALL
exit_work:
btsti r8, TIF_NEED_RESCHED
bt work_resched
/* If thread_info->flag is empty, RESTORE_ALL */
cmpnei r8, 0
bf 1b
mov a1, sp
mov a0, r8
mov a2, r11_sig /* syscall? */
btsti r8, TIF_SIGPENDING /* delivering a signal? */
/* prevent further restarts(set r11 = 0) */
clrt r11_sig
jbsr do_notify_resume /* do signals */
br resume_userspace
work_resched:
lrw syscallid, ret_from_exception
mov r15, syscallid /* Return address in link */
jmpi schedule
ENTRY(sys_rt_sigreturn)
movi r11_sig, 0
jmpi do_rt_sigreturn
ENTRY(csky_trap)
SAVE_ALL EPC_KEEP
psrset ee
movi r11_sig, 0 /* r11 = 0, Not a syscall. */
mov a0, sp /* Push Stack pointer arg */
jbsr trap_c /* Call C-level trap handler */
jmpi ret_from_exception
/*
* Prototype from libc for abiv1:
* register unsigned int __result asm("a0");
* asm( "trap 3" :"=r"(__result)::);
*/
ENTRY(csky_get_tls)
USPTOKSP
/* increase epc for continue */
mfcr a0, epc
INCTRAP a0
mtcr a0, epc
/* get current task thread_info with kernel 8K stack */
bmaski a0, THREAD_SHIFT
not a0
subi sp, 1
and a0, sp
addi sp, 1
/* get tls */
ldw a0, (a0, TINFO_TP_VALUE)
KSPTOUSP
rte
ENTRY(csky_irq)
SAVE_ALL EPC_KEEP
psrset ee
movi r11_sig, 0 /* r11 = 0, Not a syscall. */
#ifdef CONFIG_PREEMPT
mov r9, sp /* Get current stack pointer */
bmaski r10, THREAD_SHIFT
andn r9, r10 /* Get thread_info */
/*
* Get task_struct->stack.preempt_count for current,
* and increase 1.
*/
ldw r8, (r9, TINFO_PREEMPT)
addi r8, 1
stw r8, (r9, TINFO_PREEMPT)
#endif
mov a0, sp
jbsr csky_do_IRQ
#ifdef CONFIG_PREEMPT
subi r8, 1
stw r8, (r9, TINFO_PREEMPT)
cmpnei r8, 0
bt 2f
ldw r8, (r9, TINFO_FLAGS)
btsti r8, TIF_NEED_RESCHED
bf 2f
1:
jbsr preempt_schedule_irq /* irq en/disable is done inside */
ldw r7, (r9, TINFO_FLAGS) /* get new tasks TI_FLAGS */
btsti r7, TIF_NEED_RESCHED
bt 1b /* go again */
#endif
2:
jmpi ret_from_exception
/*
* a0 = prev task_struct *
* a1 = next task_struct *
* a0 = return next
*/
ENTRY(__switch_to)
lrw a3, TASK_THREAD
addu a3, a0
mfcr a2, psr /* Save PSR value */
stw a2, (a3, THREAD_SR) /* Save PSR in task struct */
bclri a2, 6 /* Disable interrupts */
mtcr a2, psr
SAVE_SWITCH_STACK
stw sp, (a3, THREAD_KSP)
/* Set up next process to run */
lrw a3, TASK_THREAD
addu a3, a1
ldw sp, (a3, THREAD_KSP) /* Set next kernel sp */
ldw a2, (a3, THREAD_SR) /* Set next PSR */
mtcr a2, psr
#if defined(__CSKYABIV2__)
addi r7, a1, TASK_THREAD_INFO
ldw tls, (r7, TINFO_TP_VALUE)
#endif
RESTORE_SWITCH_STACK
rts
ENDPROC(__switch_to)
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