Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

22 files changed, 3950 insertions, 0 deletions

diff --git a/arch/nios2/kernel/.gitignore b/arch/nios2/kernel/.gitignore
new file mode 100644
index 000000000..bbb90f92d
--- /dev/null
+++ b/arch/nios2/kernel/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+vmlinux.lds
diff --git a/arch/nios2/kernel/Makefile b/arch/nios2/kernel/Makefile
new file mode 100644
index 000000000..78a913181
--- /dev/null
+++ b/arch/nios2/kernel/Makefile
@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the nios2 linux kernel.
+#
+
+extra-y	+= vmlinux.lds
+
+obj-y	+= head.o
+obj-y	+= cpuinfo.o
+obj-y	+= entry.o
+obj-y	+= insnemu.o
+obj-y	+= irq.o
+obj-y	+= nios2_ksyms.o
+obj-y	+= process.o
+obj-y	+= prom.o
+obj-y	+= ptrace.o
+obj-y	+= setup.o
+obj-y	+= signal.o
+obj-y	+= sys_nios2.o
+obj-y	+= syscall_table.o
+obj-y	+= time.o
+obj-y	+= traps.o
+
+obj-$(CONFIG_KGDB)			+= kgdb.o
+obj-$(CONFIG_MODULES)			+= module.o
+obj-$(CONFIG_NIOS2_ALIGNMENT_TRAP)	+= misaligned.o
diff --git a/arch/nios2/kernel/asm-offsets.c b/arch/nios2/kernel/asm-offsets.c
new file mode 100644
index 000000000..e3d9b7b6f
--- /dev/null
+++ b/arch/nios2/kernel/asm-offsets.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ */
+
+#include <linux/stddef.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <linux/ptrace.h>
+#include <linux/hardirq.h>
+#include <linux/thread_info.h>
+#include <linux/kbuild.h>
+
+int main(void)
+{
+	/* struct task_struct */
+	OFFSET(TASK_THREAD, task_struct, thread);
+	BLANK();
+
+	/* struct thread_struct */
+	OFFSET(THREAD_KSP, thread_struct, ksp);
+	OFFSET(THREAD_KPSR, thread_struct, kpsr);
+	BLANK();
+
+	/* struct pt_regs */
+	OFFSET(PT_ORIG_R2, pt_regs, orig_r2);
+	OFFSET(PT_ORIG_R7, pt_regs, orig_r7);
+
+	OFFSET(PT_R1, pt_regs, r1);
+	OFFSET(PT_R2, pt_regs, r2);
+	OFFSET(PT_R3, pt_regs, r3);
+	OFFSET(PT_R4, pt_regs, r4);
+	OFFSET(PT_R5, pt_regs, r5);
+	OFFSET(PT_R6, pt_regs, r6);
+	OFFSET(PT_R7, pt_regs, r7);
+	OFFSET(PT_R8, pt_regs, r8);
+	OFFSET(PT_R9, pt_regs, r9);
+	OFFSET(PT_R10, pt_regs, r10);
+	OFFSET(PT_R11, pt_regs, r11);
+	OFFSET(PT_R12, pt_regs, r12);
+	OFFSET(PT_R13, pt_regs, r13);
+	OFFSET(PT_R14, pt_regs, r14);
+	OFFSET(PT_R15, pt_regs, r15);
+	OFFSET(PT_EA, pt_regs, ea);
+	OFFSET(PT_RA, pt_regs, ra);
+	OFFSET(PT_FP, pt_regs, fp);
+	OFFSET(PT_SP, pt_regs, sp);
+	OFFSET(PT_GP, pt_regs, gp);
+	OFFSET(PT_ESTATUS, pt_regs, estatus);
+	DEFINE(PT_REGS_SIZE, sizeof(struct pt_regs));
+	BLANK();
+
+	/* struct switch_stack */
+	OFFSET(SW_R16, switch_stack, r16);
+	OFFSET(SW_R17, switch_stack, r17);
+	OFFSET(SW_R18, switch_stack, r18);
+	OFFSET(SW_R19, switch_stack, r19);
+	OFFSET(SW_R20, switch_stack, r20);
+	OFFSET(SW_R21, switch_stack, r21);
+	OFFSET(SW_R22, switch_stack, r22);
+	OFFSET(SW_R23, switch_stack, r23);
+	OFFSET(SW_FP, switch_stack, fp);
+	OFFSET(SW_GP, switch_stack, gp);
+	OFFSET(SW_RA, switch_stack, ra);
+	DEFINE(SWITCH_STACK_SIZE, sizeof(struct switch_stack));
+	BLANK();
+
+	/* struct thread_info */
+	OFFSET(TI_FLAGS, thread_info, flags);
+	OFFSET(TI_PREEMPT_COUNT, thread_info, preempt_count);
+	BLANK();
+
+	return 0;
+}
diff --git a/arch/nios2/kernel/cpuinfo.c b/arch/nios2/kernel/cpuinfo.c
new file mode 100644
index 000000000..203870c4b
--- /dev/null
+++ b/arch/nios2/kernel/cpuinfo.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ *
+ * Based on cpuinfo.c from microblaze
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/of.h>
+#include <asm/cpuinfo.h>
+
+struct cpuinfo cpuinfo;
+
+#define err_cpu(x) \
+	pr_err("ERROR: Nios II " x " different for kernel and DTS\n")
+
+static inline u32 fcpu(struct device_node *cpu, const char *n)
+{
+	u32 val = 0;
+
+	of_property_read_u32(cpu, n, &val);
+
+	return val;
+}
+
+void __init setup_cpuinfo(void)
+{
+	struct device_node *cpu;
+	const char *str;
+	int len;
+
+	cpu = of_get_cpu_node(0, NULL);
+	if (!cpu)
+		panic("%s: No CPU found in devicetree!\n", __func__);
+
+	if (!of_property_read_bool(cpu, "altr,has-initda"))
+		panic("initda instruction is unimplemented. Please update your "
+			"hardware system to have more than 4-byte line data "
+			"cache\n");
+
+	cpuinfo.cpu_clock_freq = fcpu(cpu, "clock-frequency");
+
+	str = of_get_property(cpu, "altr,implementation", &len);
+	if (str)
+		strlcpy(cpuinfo.cpu_impl, str, sizeof(cpuinfo.cpu_impl));
+	else
+		strcpy(cpuinfo.cpu_impl, "<unknown>");
+
+	cpuinfo.has_div = of_property_read_bool(cpu, "altr,has-div");
+	cpuinfo.has_mul = of_property_read_bool(cpu, "altr,has-mul");
+	cpuinfo.has_mulx = of_property_read_bool(cpu, "altr,has-mulx");
+	cpuinfo.has_bmx = of_property_read_bool(cpu, "altr,has-bmx");
+	cpuinfo.has_cdx = of_property_read_bool(cpu, "altr,has-cdx");
+	cpuinfo.mmu = of_property_read_bool(cpu, "altr,has-mmu");
+
+	if (IS_ENABLED(CONFIG_NIOS2_HW_DIV_SUPPORT) && !cpuinfo.has_div)
+		err_cpu("DIV");
+
+	if (IS_ENABLED(CONFIG_NIOS2_HW_MUL_SUPPORT) && !cpuinfo.has_mul)
+		err_cpu("MUL");
+
+	if (IS_ENABLED(CONFIG_NIOS2_HW_MULX_SUPPORT) && !cpuinfo.has_mulx)
+		err_cpu("MULX");
+
+	if (IS_ENABLED(CONFIG_NIOS2_BMX_SUPPORT) && !cpuinfo.has_bmx)
+		err_cpu("BMX");
+
+	if (IS_ENABLED(CONFIG_NIOS2_CDX_SUPPORT) && !cpuinfo.has_cdx)
+		err_cpu("CDX");
+
+	cpuinfo.tlb_num_ways = fcpu(cpu, "altr,tlb-num-ways");
+	if (!cpuinfo.tlb_num_ways)
+		panic("altr,tlb-num-ways can't be 0. Please check your hardware "
+			"system\n");
+	cpuinfo.icache_line_size = fcpu(cpu, "icache-line-size");
+	cpuinfo.icache_size = fcpu(cpu, "icache-size");
+	if (CONFIG_NIOS2_ICACHE_SIZE != cpuinfo.icache_size)
+		pr_warn("Warning: icache size configuration mismatch "
+		"(0x%x vs 0x%x) of CONFIG_NIOS2_ICACHE_SIZE vs "
+		"device tree icache-size\n",
+		CONFIG_NIOS2_ICACHE_SIZE, cpuinfo.icache_size);
+
+	cpuinfo.dcache_line_size = fcpu(cpu, "dcache-line-size");
+	if (CONFIG_NIOS2_DCACHE_LINE_SIZE != cpuinfo.dcache_line_size)
+		pr_warn("Warning: dcache line size configuration mismatch "
+		"(0x%x vs 0x%x) of CONFIG_NIOS2_DCACHE_LINE_SIZE vs "
+		"device tree dcache-line-size\n",
+		CONFIG_NIOS2_DCACHE_LINE_SIZE, cpuinfo.dcache_line_size);
+	cpuinfo.dcache_size = fcpu(cpu, "dcache-size");
+	if (CONFIG_NIOS2_DCACHE_SIZE != cpuinfo.dcache_size)
+		pr_warn("Warning: dcache size configuration mismatch "
+			"(0x%x vs 0x%x) of CONFIG_NIOS2_DCACHE_SIZE vs "
+			"device tree dcache-size\n",
+			CONFIG_NIOS2_DCACHE_SIZE, cpuinfo.dcache_size);
+
+	cpuinfo.tlb_pid_num_bits = fcpu(cpu, "altr,pid-num-bits");
+	cpuinfo.tlb_num_ways_log2 = ilog2(cpuinfo.tlb_num_ways);
+	cpuinfo.tlb_num_entries = fcpu(cpu, "altr,tlb-num-entries");
+	cpuinfo.tlb_num_lines = cpuinfo.tlb_num_entries / cpuinfo.tlb_num_ways;
+	cpuinfo.tlb_ptr_sz = fcpu(cpu, "altr,tlb-ptr-sz");
+
+	cpuinfo.reset_addr = fcpu(cpu, "altr,reset-addr");
+	cpuinfo.exception_addr = fcpu(cpu, "altr,exception-addr");
+	cpuinfo.fast_tlb_miss_exc_addr = fcpu(cpu, "altr,fast-tlb-miss-addr");
+
+	of_node_put(cpu);
+}
+
+#ifdef CONFIG_PROC_FS
+
+/*
+ * Get CPU information for use by the procfs.
+ */
+static int show_cpuinfo(struct seq_file *m, void *v)
+{
+	const u32 clockfreq = cpuinfo.cpu_clock_freq;
+
+	seq_printf(m,
+		   "CPU:\t\tNios II/%s\n"
+		   "REV:\t\t%i\n"
+		   "MMU:\t\t%s\n"
+		   "FPU:\t\tnone\n"
+		   "Clocking:\t%u.%02u MHz\n"
+		   "BogoMips:\t%lu.%02lu\n"
+		   "Calibration:\t%lu loops\n",
+		   cpuinfo.cpu_impl,
+		   CONFIG_NIOS2_ARCH_REVISION,
+		   cpuinfo.mmu ? "present" : "none",
+		   clockfreq / 1000000, (clockfreq / 100000) % 10,
+		   (loops_per_jiffy * HZ) / 500000,
+		   ((loops_per_jiffy * HZ) / 5000) % 100,
+		   (loops_per_jiffy * HZ));
+
+	seq_printf(m,
+		   "HW:\n"
+		   " MUL:\t\t%s\n"
+		   " MULX:\t\t%s\n"
+		   " DIV:\t\t%s\n"
+		   " BMX:\t\t%s\n"
+		   " CDX:\t\t%s\n",
+		   cpuinfo.has_mul ? "yes" : "no",
+		   cpuinfo.has_mulx ? "yes" : "no",
+		   cpuinfo.has_div ? "yes" : "no",
+		   cpuinfo.has_bmx ? "yes" : "no",
+		   cpuinfo.has_cdx ? "yes" : "no");
+
+	seq_printf(m,
+		   "Icache:\t\t%ukB, line length: %u\n",
+		   cpuinfo.icache_size >> 10,
+		   cpuinfo.icache_line_size);
+
+	seq_printf(m,
+		   "Dcache:\t\t%ukB, line length: %u\n",
+		   cpuinfo.dcache_size >> 10,
+		   cpuinfo.dcache_line_size);
+
+	seq_printf(m,
+		   "TLB:\t\t%u ways, %u entries, %u PID bits\n",
+		   cpuinfo.tlb_num_ways,
+		   cpuinfo.tlb_num_entries,
+		   cpuinfo.tlb_pid_num_bits);
+
+	return 0;
+}
+
+static void *cpuinfo_start(struct seq_file *m, loff_t *pos)
+{
+	unsigned long i = *pos;
+
+	return i < num_possible_cpus() ? (void *) (i + 1) : NULL;
+}
+
+static void *cpuinfo_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	++*pos;
+	return cpuinfo_start(m, pos);
+}
+
+static void cpuinfo_stop(struct seq_file *m, void *v)
+{
+}
+
+const struct seq_operations cpuinfo_op = {
+	.start	= cpuinfo_start,
+	.next	= cpuinfo_next,
+	.stop	= cpuinfo_stop,
+	.show	= show_cpuinfo
+};
+
+#endif /* CONFIG_PROC_FS */
diff --git a/arch/nios2/kernel/entry.S b/arch/nios2/kernel/entry.S
new file mode 100644
index 000000000..99f0a65e6
--- /dev/null
+++ b/arch/nios2/kernel/entry.S
@@ -0,0 +1,568 @@
+/*
+ * linux/arch/nios2/kernel/entry.S
+ *
+ * Copyright (C) 2013-2014  Altera Corporation
+ * Copyright (C) 2009, Wind River Systems Inc
+ *
+ * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ *
+ *  Copyright (C) 1999-2002, Greg Ungerer (gerg@snapgear.com)
+ *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
+ *                      Kenneth Albanowski <kjahds@kjahds.com>,
+ *  Copyright (C) 2000  Lineo Inc. (www.lineo.com)
+ *  Copyright (C) 2004  Microtronix Datacom Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Linux/m68k support by Hamish Macdonald
+ *
+ * 68060 fixes by Jesper Skov
+ * ColdFire support by Greg Ungerer (gerg@snapgear.com)
+ * 5307 fixes by David W. Miller
+ * linux 2.4 support David McCullough <davidm@snapgear.com>
+ */
+
+#include <linux/sys.h>
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/asm-macros.h>
+#include <asm/thread_info.h>
+#include <asm/errno.h>
+#include <asm/setup.h>
+#include <asm/entry.h>
+#include <asm/unistd.h>
+#include <asm/processor.h>
+
+.macro GET_THREAD_INFO reg
+.if THREAD_SIZE & 0xffff0000
+	andhi	\reg, sp, %hi(~(THREAD_SIZE-1))
+.else
+	addi	\reg, r0, %lo(~(THREAD_SIZE-1))
+	and	\reg, \reg, sp
+.endif
+.endm
+
+.macro	kuser_cmpxchg_check
+	/*
+	 * Make sure our user space atomic helper is restarted if it was
+	 * interrupted in a critical region.
+	 * ea-4 = address of interrupted insn (ea must be preserved).
+	 * sp = saved regs.
+	 * cmpxchg_ldw = first critical insn, cmpxchg_stw = last critical insn.
+	 * If ea <= cmpxchg_stw and ea > cmpxchg_ldw then saved EA is set to
+	 * cmpxchg_ldw + 4.
+	*/
+	/* et = cmpxchg_stw + 4 */
+	movui   et, (KUSER_BASE + 4 + (cmpxchg_stw - __kuser_helper_start))
+	bgtu	ea, et, 1f
+
+	subi	et, et, (cmpxchg_stw - cmpxchg_ldw) /* et = cmpxchg_ldw + 4 */
+	bltu	ea, et, 1f
+	stw	et, PT_EA(sp)	/* fix up EA */
+	mov	ea, et
+1:
+.endm
+
+.section .rodata
+.align 4
+exception_table:
+	.word unhandled_exception	/* 0 - Reset */
+	.word unhandled_exception	/* 1 - Processor-only Reset */
+	.word external_interrupt	/* 2 - Interrupt */
+	.word handle_trap		/* 3 - Trap Instruction */
+
+	.word instruction_trap		/* 4 - Unimplemented instruction */
+	.word handle_illegal		/* 5 - Illegal instruction */
+	.word handle_unaligned		/* 6 - Misaligned data access */
+	.word handle_unaligned		/* 7 - Misaligned destination address */
+
+	.word handle_diverror		/* 8 - Division error */
+	.word protection_exception_ba	/* 9 - Supervisor-only instr. address */
+	.word protection_exception_instr /* 10 - Supervisor only instruction */
+	.word protection_exception_ba	/* 11 - Supervisor only data address */
+
+	.word unhandled_exception	/* 12 - Double TLB miss (data) */
+	.word protection_exception_pte	/* 13 - TLB permission violation (x) */
+	.word protection_exception_pte	/* 14 - TLB permission violation (r) */
+	.word protection_exception_pte	/* 15 - TLB permission violation (w) */
+
+	.word unhandled_exception	/* 16 - MPU region violation */
+
+trap_table:
+	.word	handle_system_call	/* 0  */
+	.word	handle_trap_1		/* 1  */
+	.word	handle_trap_2		/* 2  */
+	.word	handle_trap_3		/* 3  */
+	.word	handle_trap_reserved	/* 4  */
+	.word	handle_trap_reserved	/* 5  */
+	.word	handle_trap_reserved	/* 6  */
+	.word	handle_trap_reserved	/* 7  */
+	.word	handle_trap_reserved	/* 8  */
+	.word	handle_trap_reserved	/* 9  */
+	.word	handle_trap_reserved	/* 10 */
+	.word	handle_trap_reserved	/* 11 */
+	.word	handle_trap_reserved	/* 12 */
+	.word	handle_trap_reserved	/* 13 */
+	.word	handle_trap_reserved	/* 14 */
+	.word	handle_trap_reserved	/* 15 */
+	.word	handle_trap_reserved	/* 16 */
+	.word	handle_trap_reserved	/* 17 */
+	.word	handle_trap_reserved	/* 18 */
+	.word	handle_trap_reserved	/* 19 */
+	.word	handle_trap_reserved	/* 20 */
+	.word	handle_trap_reserved	/* 21 */
+	.word	handle_trap_reserved	/* 22 */
+	.word	handle_trap_reserved	/* 23 */
+	.word	handle_trap_reserved	/* 24 */
+	.word	handle_trap_reserved	/* 25 */
+	.word	handle_trap_reserved	/* 26 */
+	.word	handle_trap_reserved	/* 27 */
+	.word	handle_trap_reserved	/* 28 */
+	.word	handle_trap_reserved	/* 29 */
+#ifdef CONFIG_KGDB
+	.word	handle_kgdb_breakpoint	/* 30 KGDB breakpoint */
+#else
+	.word	instruction_trap		/* 30 */
+#endif
+	.word	handle_breakpoint	/* 31 */
+
+.text
+.set noat
+.set nobreak
+
+ENTRY(inthandler)
+	SAVE_ALL
+
+	kuser_cmpxchg_check
+
+	/* Clear EH bit before we get a new excpetion in the kernel
+	 * and after we have saved it to the exception frame. This is done
+	 * whether it's trap, tlb-miss or interrupt. If we don't do this
+	 * estatus is not updated the next exception.
+	 */
+	rdctl	r24, status
+	movi	r9, %lo(~STATUS_EH)
+	and	r24, r24, r9
+	wrctl	status, r24
+
+	/* Read cause and vector and branch to the associated handler */
+	mov	r4, sp
+	rdctl	r5, exception
+	movia	r9, exception_table
+	add	r24, r9, r5
+	ldw	r24, 0(r24)
+	jmp	r24
+
+
+/***********************************************************************
+ * Handle traps
+ ***********************************************************************
+ */
+ENTRY(handle_trap)
+	ldwio	r24, -4(ea)	/* instruction that caused the exception */
+	srli	r24, r24, 4
+	andi	r24, r24, 0x7c
+	movia	r9,trap_table
+	add	r24, r24, r9
+	ldw	r24, 0(r24)
+	jmp	r24
+
+
+/***********************************************************************
+ * Handle system calls
+ ***********************************************************************
+ */
+ENTRY(handle_system_call)
+	/* Enable interrupts */
+	rdctl	r10, status
+	ori	r10, r10, STATUS_PIE
+	wrctl	status, r10
+
+	/* Reload registers destroyed by common code. */
+	ldw	r4, PT_R4(sp)
+	ldw	r5, PT_R5(sp)
+
+local_restart:
+	stw	r2, PT_ORIG_R2(sp)
+	/* Check that the requested system call is within limits */
+	movui	r1, __NR_syscalls
+	bgeu	r2, r1, ret_invsyscall
+	slli	r1, r2, 2
+	movhi	r11, %hiadj(sys_call_table)
+	add	r1, r1, r11
+	ldw	r1, %lo(sys_call_table)(r1)
+
+	/* Check if we are being traced */
+	GET_THREAD_INFO r11
+	ldw	r11,TI_FLAGS(r11)
+	BTBNZ   r11,r11,TIF_SYSCALL_TRACE,traced_system_call
+
+	/* Execute the system call */
+	callr	r1
+
+	/* If the syscall returns a negative result:
+	 *   Set r7 to 1 to indicate error,
+	 *   Negate r2 to get a positive error code
+	 * If the syscall returns zero or a positive value:
+	 *   Set r7 to 0.
+	 * The sigreturn system calls will skip the code below by
+	 * adding to register ra. To avoid destroying registers
+	 */
+translate_rc_and_ret:
+	movi	r1, 0
+	bge	r2, zero, 3f
+	ldw	r1, PT_ORIG_R2(sp)
+	addi	r1, r1, 1
+	beq	r1, zero, 3f
+	sub	r2, zero, r2
+	movi	r1, 1
+3:
+	stw	r2, PT_R2(sp)
+	stw	r1, PT_R7(sp)
+end_translate_rc_and_ret:
+
+ret_from_exception:
+	ldw	r1, PT_ESTATUS(sp)
+	/* if so, skip resched, signals */
+	TSTBNZ	r1, r1, ESTATUS_EU, Luser_return
+
+restore_all:
+	rdctl	r10, status			/* disable intrs */
+	andi	r10, r10, %lo(~STATUS_PIE)
+	wrctl	status, r10
+	RESTORE_ALL
+	eret
+
+	/* If the syscall number was invalid return ENOSYS */
+ret_invsyscall:
+	movi	r2, -ENOSYS
+	br	translate_rc_and_ret
+
+	/* This implements the same as above, except it calls
+	 * do_syscall_trace_enter and do_syscall_trace_exit before and after the
+	 * syscall in order for utilities like strace and gdb to work.
+	 */
+traced_system_call:
+	SAVE_SWITCH_STACK
+	call	do_syscall_trace_enter
+	RESTORE_SWITCH_STACK
+
+	/* Create system call register arguments. The 5th and 6th
+	   arguments on stack are already in place at the beginning
+	   of pt_regs. */
+	ldw	r2, PT_R2(sp)
+	ldw	r4, PT_R4(sp)
+	ldw	r5, PT_R5(sp)
+	ldw	r6, PT_R6(sp)
+	ldw	r7, PT_R7(sp)
+
+	/* Fetch the syscall function. */
+	movui	r1, __NR_syscalls
+	bgeu	r2, r1, traced_invsyscall
+	slli	r1, r2, 2
+	movhi	r11,%hiadj(sys_call_table)
+	add	r1, r1, r11
+	ldw	r1, %lo(sys_call_table)(r1)
+
+	callr	r1
+
+	/* If the syscall returns a negative result:
+	 *   Set r7 to 1 to indicate error,
+	 *   Negate r2 to get a positive error code
+	 * If the syscall returns zero or a positive value:
+	 *   Set r7 to 0.
+	 * The sigreturn system calls will skip the code below by
+	 * adding to register ra. To avoid destroying registers
+	 */
+translate_rc_and_ret2:
+	movi	r1, 0
+	bge	r2, zero, 4f
+	ldw	r1, PT_ORIG_R2(sp)
+	addi	r1, r1, 1
+	beq	r1, zero, 4f
+	sub	r2, zero, r2
+	movi	r1, 1
+4:
+	stw	r2, PT_R2(sp)
+	stw	r1, PT_R7(sp)
+end_translate_rc_and_ret2:
+	SAVE_SWITCH_STACK
+	call	do_syscall_trace_exit
+	RESTORE_SWITCH_STACK
+	br	ret_from_exception
+
+	/* If the syscall number was invalid return ENOSYS */
+traced_invsyscall:
+	movi	r2, -ENOSYS
+	br	translate_rc_and_ret2
+
+Luser_return:
+	GET_THREAD_INFO	r11			/* get thread_info pointer */
+	ldw	r10, TI_FLAGS(r11)		/* get thread_info->flags */
+	ANDI32	r11, r10, _TIF_WORK_MASK
+	beq	r11, r0, restore_all		/* Nothing to do */
+	BTBZ	r1, r10, TIF_NEED_RESCHED, Lsignal_return
+
+	/* Reschedule work */
+	call	schedule
+	br	ret_from_exception
+
+Lsignal_return:
+	ANDI32	r1, r10, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME
+	beq	r1, r0, restore_all
+	mov	r4, sp			/* pt_regs */
+	SAVE_SWITCH_STACK
+	call	do_notify_resume
+	beq	r2, r0, no_work_pending
+	RESTORE_SWITCH_STACK
+	/* prepare restart syscall here without leaving kernel */
+	ldw	r2, PT_R2(sp)	/* reload syscall number in r2 */
+	ldw 	r4, PT_R4(sp)	/* reload syscall arguments r4-r9 */
+	ldw 	r5, PT_R5(sp)
+	ldw 	r6, PT_R6(sp)
+	ldw 	r7, PT_R7(sp)
+	ldw 	r8, PT_R8(sp)
+	ldw 	r9, PT_R9(sp)
+	br	local_restart	/* restart syscall */
+
+no_work_pending:
+	RESTORE_SWITCH_STACK
+	br	ret_from_exception
+
+/***********************************************************************
+ * Handle external interrupts.
+ ***********************************************************************
+ */
+/*
+ * This is the generic interrupt handler (for all hardware interrupt
+ * sources). It figures out the vector number and calls the appropriate
+ * interrupt service routine directly.
+ */
+external_interrupt:
+	rdctl	r12, ipending
+	rdctl	r9, ienable
+	and	r12, r12, r9
+	/* skip if no interrupt is pending */
+	beq	r12, r0, ret_from_interrupt
+
+	/*
+	 * Process an external hardware interrupt.
+	 */
+
+	addi	ea, ea, -4	/* re-issue the interrupted instruction */
+	stw	ea, PT_EA(sp)
+2:	movi	r4, %lo(-1)	/* Start from bit position 0,
+					highest priority */
+				/* This is the IRQ # for handler call */
+1:	andi	r10, r12, 1	/* Isolate bit we are interested in */
+	srli	r12, r12, 1	/* shift count is costly without hardware
+					multiplier */
+	addi	r4, r4, 1
+	beq	r10, r0, 1b
+	mov	r5, sp		/* Setup pt_regs pointer for handler call */
+	call	do_IRQ
+	rdctl	r12, ipending	/* check again if irq still pending */
+	rdctl	r9, ienable	/* Isolate possible interrupts */
+	and	r12, r12, r9
+	bne	r12, r0, 2b
+	/* br	ret_from_interrupt */ /* fall through to ret_from_interrupt */
+
+ENTRY(ret_from_interrupt)
+	ldw	r1, PT_ESTATUS(sp)	/* check if returning to kernel */
+	TSTBNZ	r1, r1, ESTATUS_EU, Luser_return
+
+#ifdef CONFIG_PREEMPTION
+	GET_THREAD_INFO	r1
+	ldw	r4, TI_PREEMPT_COUNT(r1)
+	bne	r4, r0, restore_all
+	ldw	r4, TI_FLAGS(r1)		/* ? Need resched set */
+	BTBZ	r10, r4, TIF_NEED_RESCHED, restore_all
+	ldw	r4, PT_ESTATUS(sp)	/* ? Interrupts off */
+	andi	r10, r4, ESTATUS_EPIE
+	beq	r10, r0, restore_all
+	call	preempt_schedule_irq
+#endif
+	br	restore_all
+
+/***********************************************************************
+ * A few syscall wrappers
+ ***********************************************************************
+ */
+/*
+ * int clone(unsigned long clone_flags, unsigned long newsp,
+ *		int __user * parent_tidptr, int __user * child_tidptr,
+ *		int tls_val)
+ */
+ENTRY(sys_clone)
+	SAVE_SWITCH_STACK
+	subi    sp, sp, 4 /* make space for tls pointer */
+	stw     r8, 0(sp) /* pass tls pointer (r8) via stack (5th argument) */
+	call	nios2_clone
+	addi    sp, sp, 4
+	RESTORE_SWITCH_STACK
+	ret
+
+ENTRY(sys_rt_sigreturn)
+	SAVE_SWITCH_STACK
+	mov	r4, sp
+	call	do_rt_sigreturn
+	RESTORE_SWITCH_STACK
+	addi	ra, ra, (end_translate_rc_and_ret - translate_rc_and_ret)
+	ret
+
+/***********************************************************************
+ * A few other wrappers and stubs
+ ***********************************************************************
+ */
+protection_exception_pte:
+	rdctl	r6, pteaddr
+	slli	r6, r6, 10
+	call	do_page_fault
+	br	ret_from_exception
+
+protection_exception_ba:
+	rdctl	r6, badaddr
+	call	do_page_fault
+	br	ret_from_exception
+
+protection_exception_instr:
+	call	handle_supervisor_instr
+	br	ret_from_exception
+
+handle_breakpoint:
+	call	breakpoint_c
+	br	ret_from_exception
+
+#ifdef CONFIG_NIOS2_ALIGNMENT_TRAP
+handle_unaligned:
+	SAVE_SWITCH_STACK
+	call	handle_unaligned_c
+	RESTORE_SWITCH_STACK
+	br	ret_from_exception
+#else
+handle_unaligned:
+	call	handle_unaligned_c
+	br	ret_from_exception
+#endif
+
+handle_illegal:
+	call	handle_illegal_c
+	br	ret_from_exception
+
+handle_diverror:
+	call	handle_diverror_c
+	br	ret_from_exception
+
+#ifdef CONFIG_KGDB
+handle_kgdb_breakpoint:
+	call	kgdb_breakpoint_c
+	br	ret_from_exception
+#endif
+
+handle_trap_1:
+	call	handle_trap_1_c
+	br	ret_from_exception
+
+handle_trap_2:
+	call	handle_trap_2_c
+	br	ret_from_exception
+
+handle_trap_3:
+handle_trap_reserved:
+	call	handle_trap_3_c
+	br	ret_from_exception
+
+/*
+ * Beware - when entering resume, prev (the current task) is
+ * in r4, next (the new task) is in r5, don't change these
+ * registers.
+ */
+ENTRY(resume)
+
+	rdctl	r7, status			/* save thread status reg */
+	stw	r7, TASK_THREAD + THREAD_KPSR(r4)
+
+	andi	r7, r7, %lo(~STATUS_PIE)	/* disable interrupts */
+	wrctl	status, r7
+
+	SAVE_SWITCH_STACK
+	stw	sp, TASK_THREAD + THREAD_KSP(r4)/* save kernel stack pointer */
+	ldw	sp, TASK_THREAD + THREAD_KSP(r5)/* restore new thread stack */
+	movia	r24, _current_thread		/* save thread */
+	GET_THREAD_INFO r1
+	stw	r1, 0(r24)
+	RESTORE_SWITCH_STACK
+
+	ldw	r7, TASK_THREAD + THREAD_KPSR(r5)/* restore thread status reg */
+	wrctl	status, r7
+	ret
+
+ENTRY(ret_from_fork)
+	call	schedule_tail
+	br	ret_from_exception
+
+ENTRY(ret_from_kernel_thread)
+	call	schedule_tail
+	mov	r4,r17	/* arg */
+	callr	r16	/* function */
+	br	ret_from_exception
+
+/*
+ * Kernel user helpers.
+ *
+ * Each segment is 64-byte aligned and will be mapped to the <User space>.
+ * New segments (if ever needed) must be added after the existing ones.
+ * This mechanism should be used only for things that are really small and
+ * justified, and not be abused freely.
+ *
+ */
+
+ /* Filling pads with undefined instructions. */
+.macro	kuser_pad sym size
+	.if	((. - \sym) & 3)
+	.rept	(4 - (. - \sym) & 3)
+	.byte	0
+	.endr
+	.endif
+	.rept	((\size - (. - \sym)) / 4)
+	.word	0xdeadbeef
+	.endr
+.endm
+
+	.align	6
+	.globl	__kuser_helper_start
+__kuser_helper_start:
+
+__kuser_helper_version:				/* @ 0x1000 */
+	.word	((__kuser_helper_end - __kuser_helper_start) >> 6)
+
+__kuser_cmpxchg:				/* @ 0x1004 */
+	/*
+	 * r4 pointer to exchange variable
+	 * r5 old value
+	 * r6 new value
+	 */
+cmpxchg_ldw:
+	ldw	r2, 0(r4)			/* load current value */
+	sub	r2, r2, r5			/* compare with old value */
+	bne	r2, zero, cmpxchg_ret
+
+	/* We had a match, store the new value */
+cmpxchg_stw:
+	stw	r6, 0(r4)
+cmpxchg_ret:
+	ret
+
+	kuser_pad __kuser_cmpxchg, 64
+
+	.globl	__kuser_sigtramp
+__kuser_sigtramp:
+	movi	r2, __NR_rt_sigreturn
+	trap
+
+	kuser_pad __kuser_sigtramp, 64
+
+	.globl	__kuser_helper_end
+__kuser_helper_end:
diff --git a/arch/nios2/kernel/head.S b/arch/nios2/kernel/head.S
new file mode 100644
index 000000000..372ce4a33
--- /dev/null
+++ b/arch/nios2/kernel/head.S
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2009 Wind River Systems Inc
+ *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ * Copyright (C) 2004 Microtronix Datacom Ltd
+ * Copyright (C) 2001 Vic Phillips, Microtronix Datacom Ltd.
+ *
+ * Based on head.S for Altera's Excalibur development board with nios processor
+ *
+ * Based on the following from the Excalibur sdk distribution:
+ *	NA_MemoryMap.s, NR_JumpToStart.s, NR_Setup.s, NR_CWPManager.s
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/thread_info.h>
+#include <asm/processor.h>
+#include <asm/cache.h>
+#include <asm/page.h>
+#include <asm/asm-offsets.h>
+#include <asm/asm-macros.h>
+
+/*
+ * ZERO_PAGE is a special page that is used for zero-initialized
+ * data and COW.
+ */
+.data
+.global empty_zero_page
+.align 12
+empty_zero_page:
+	.space	PAGE_SIZE
+
+/*
+ * This global variable is used as an extension to the nios'
+ * STATUS register to emulate a user/supervisor mode.
+ */
+	.data
+	.align	2
+	.set noat
+
+	.global _current_thread
+_current_thread:
+	.long	0
+/*
+ * Input(s): passed from u-boot
+ *   r4 - Optional pointer to a board information structure.
+ *   r5 - Optional pointer to the physical starting address of the init RAM
+ *        disk.
+ *   r6 - Optional pointer to the physical ending address of the init RAM
+ *        disk.
+ *   r7 - Optional pointer to the physical starting address of any kernel
+ *        command-line parameters.
+ */
+
+/*
+ * First executable code - detected and jumped to by the ROM bootstrap
+ * if the code resides in flash (looks for "Nios" at offset 0x0c from
+ * the potential executable image).
+ */
+	__HEAD
+ENTRY(_start)
+	wrctl	status, r0		/* Disable interrupts */
+
+	/* Initialize all cache lines within the instruction cache */
+	movia	r1, NIOS2_ICACHE_SIZE
+	movui	r2, NIOS2_ICACHE_LINE_SIZE
+
+icache_init:
+	initi	r1
+	sub	r1, r1, r2
+	bgt	r1, r0, icache_init
+	br	1f
+
+	/*
+	 * This is the default location for the exception handler. Code in jump
+	 * to our handler
+	 */
+ENTRY(exception_handler_hook)
+	movia	r24, inthandler
+	jmp	r24
+
+ENTRY(fast_handler)
+	nextpc et
+helper:
+	stw	r3, r3save - helper(et)
+
+	rdctl	r3 , pteaddr
+	srli	r3, r3, 12
+	slli	r3, r3, 2
+	movia	et, pgd_current
+
+	ldw	et, 0(et)
+	add	r3, et, r3
+	ldw	et, 0(r3)
+
+	rdctl	r3, pteaddr
+	andi	r3, r3, 0xfff
+	add	et, r3, et
+	ldw	et, 0(et)
+	wrctl	tlbacc, et
+	nextpc	et
+helper2:
+	ldw	r3, r3save - helper2(et)
+	subi	ea, ea, 4
+	eret
+r3save:
+	.word 0x0
+ENTRY(fast_handler_end)
+
+1:
+	/*
+	 * After the instruction cache is initialized, the data cache must
+	 * also be initialized.
+	 */
+	movia	r1, NIOS2_DCACHE_SIZE
+	movui	r2, NIOS2_DCACHE_LINE_SIZE
+
+dcache_init:
+	initd	0(r1)
+	sub	r1, r1, r2
+	bgt	r1, r0, dcache_init
+
+	nextpc	r1			/* Find out where we are */
+chkadr:
+	movia	r2, chkadr
+	beq	r1, r2,finish_move	/* We are running in RAM done */
+	addi	r1, r1,(_start - chkadr)	/* Source */
+	movia	r2, _start		/* Destination */
+	movia	r3, __bss_start		/* End of copy */
+
+loop_move:				/* r1: src, r2: dest, r3: last dest */
+	ldw	r8, 0(r1)		/* load a word from [r1] */
+	stw	r8, 0(r2)		/* store a word to dest [r2] */
+	flushd	0(r2)			/* Flush cache for safety */
+	addi 	r1, r1, 4		/* inc the src addr */
+	addi	r2, r2, 4		/* inc the dest addr */
+	blt	r2, r3, loop_move
+
+	movia	r1, finish_move		/* VMA(_start)->l1 */
+	jmp	r1			/* jmp to _start */
+
+finish_move:
+
+	/* Mask off all possible interrupts */
+	wrctl	ienable, r0
+
+	/* Clear .bss */
+	movia	r2, __bss_start
+	movia	r1, __bss_stop
+1:
+	stb	r0, 0(r2)
+	addi	r2, r2, 1
+	bne	r1, r2, 1b
+
+	movia	r1, init_thread_union	/* set stack at top of the task union */
+	addi	sp, r1, THREAD_SIZE
+	movia	r2, _current_thread	/* Remember current thread */
+	stw	r1, 0(r2)
+
+	movia	r1, nios2_boot_init	/* save args r4-r7 passed from u-boot */
+	callr	r1
+
+	movia	r1, start_kernel	/* call start_kernel as a subroutine */
+	callr	r1
+
+	/* If we return from start_kernel, break to the oci debugger and
+	 * buggered we are.
+	 */
+	break
+
+	/* End of startup code */
+.set at
diff --git a/arch/nios2/kernel/insnemu.S b/arch/nios2/kernel/insnemu.S
new file mode 100644
index 000000000..a027cc68b
--- /dev/null
+++ b/arch/nios2/kernel/insnemu.S
@@ -0,0 +1,580 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  Copyright (C) 2003-2013 Altera Corporation
+ *  All rights reserved.
+ */
+
+
+#include <linux/linkage.h>
+#include <asm/entry.h>
+
+.set noat
+.set nobreak
+
+/*
+* Explicitly allow the use of r1 (the assembler temporary register)
+* within this code. This register is normally reserved for the use of
+* the compiler.
+*/
+
+ENTRY(instruction_trap)
+	ldw	r1, PT_R1(sp)		// Restore registers
+	ldw	r2, PT_R2(sp)
+	ldw	r3, PT_R3(sp)
+	ldw	r4, PT_R4(sp)
+	ldw	r5, PT_R5(sp)
+	ldw	r6, PT_R6(sp)
+	ldw	r7, PT_R7(sp)
+	ldw	r8, PT_R8(sp)
+	ldw	r9, PT_R9(sp)
+	ldw	r10, PT_R10(sp)
+	ldw	r11, PT_R11(sp)
+	ldw	r12, PT_R12(sp)
+	ldw	r13, PT_R13(sp)
+	ldw	r14, PT_R14(sp)
+	ldw	r15, PT_R15(sp)
+	ldw	ra, PT_RA(sp)
+	ldw	fp, PT_FP(sp)
+	ldw	gp, PT_GP(sp)
+	ldw	et, PT_ESTATUS(sp)
+	wrctl	estatus, et
+	ldw	ea, PT_EA(sp)
+	ldw	et, PT_SP(sp)		/* backup sp in et */
+
+	addi	sp, sp, PT_REGS_SIZE
+
+	/* INSTRUCTION EMULATION
+	*  ---------------------
+	*
+	* Nios II processors generate exceptions for unimplemented instructions.
+	* The routines below emulate these instructions.  Depending on the
+	* processor core, the only instructions that might need to be emulated
+	* are div, divu, mul, muli, mulxss, mulxsu, and mulxuu.
+	*
+	* The emulations match the instructions, except for the following
+	* limitations:
+	*
+	* 1) The emulation routines do not emulate the use of the exception
+	*    temporary register (et) as a source operand because the exception
+	*    handler already has modified it.
+	*
+	* 2) The routines do not emulate the use of the stack pointer (sp) or
+	*    the exception return address register (ea) as a destination because
+	*    modifying these registers crashes the exception handler or the
+	*    interrupted routine.
+	*
+	* Detailed Design
+	* ---------------
+	*
+	* The emulation routines expect the contents of integer registers r0-r31
+	* to be on the stack at addresses sp, 4(sp), 8(sp), ... 124(sp).  The
+	* routines retrieve source operands from the stack and modify the
+	* destination register's value on the stack prior to the end of the
+	* exception handler.  Then all registers except the destination register
+	* are restored to their previous values.
+	*
+	* The instruction that causes the exception is found at address -4(ea).
+	* The instruction's OP and OPX fields identify the operation to be
+	* performed.
+	*
+	* One instruction, muli, is an I-type instruction that is identified by
+	* an OP field of 0x24.
+	*
+	* muli   AAAAA,BBBBB,IIIIIIIIIIIIIIII,-0x24-
+	*           27    22                6      0    <-- LSB of field
+	*
+	* The remaining emulated instructions are R-type and have an OP field
+	* of 0x3a.  Their OPX fields identify them.
+	*
+	* R-type AAAAA,BBBBB,CCCCC,XXXXXX,NNNNN,-0x3a-
+	*           27    22    17     11     6      0  <-- LSB of field
+	*
+	*
+	* Opcode Encoding.  muli is identified by its OP value.  Then OPX & 0x02
+	* is used to differentiate between the division opcodes and the
+	* remaining multiplication opcodes.
+	*
+	* Instruction   OP      OPX    OPX & 0x02
+	* -----------   ----    ----   ----------
+	* muli          0x24
+	* divu          0x3a    0x24         0
+	* div           0x3a    0x25         0
+	* mul           0x3a    0x27      != 0
+	* mulxuu        0x3a    0x07      != 0
+	* mulxsu        0x3a    0x17      != 0
+	* mulxss        0x3a    0x1f      != 0
+	*/
+
+
+	/*
+	* Save everything on the stack to make it easy for the emulation
+	* routines to retrieve the source register operands.
+	*/
+
+	addi sp, sp, -128
+	stw zero, 0(sp)	/* Save zero on stack to avoid special case for r0. */
+	stw r1, 4(sp)
+	stw r2,  8(sp)
+	stw r3, 12(sp)
+	stw r4, 16(sp)
+	stw r5, 20(sp)
+	stw r6, 24(sp)
+	stw r7, 28(sp)
+	stw r8, 32(sp)
+	stw r9, 36(sp)
+	stw r10, 40(sp)
+	stw r11, 44(sp)
+	stw r12, 48(sp)
+	stw r13, 52(sp)
+	stw r14, 56(sp)
+	stw r15, 60(sp)
+	stw r16, 64(sp)
+	stw r17, 68(sp)
+	stw r18, 72(sp)
+	stw r19, 76(sp)
+	stw r20, 80(sp)
+	stw r21, 84(sp)
+	stw r22, 88(sp)
+	stw r23, 92(sp)
+		/* Don't bother to save et.  It's already been changed. */
+	rdctl r5, estatus
+	stw r5,  100(sp)
+
+	stw gp, 104(sp)
+	stw et, 108(sp)	/* et contains previous sp value. */
+	stw fp, 112(sp)
+	stw ea, 116(sp)
+	stw ra, 120(sp)
+
+
+	/*
+	* Split the instruction into its fields.  We need 4*A, 4*B, and 4*C as
+	* offsets to the stack pointer for access to the stored register values.
+	*/
+	ldw r2,-4(ea)	/* r2 = AAAAA,BBBBB,IIIIIIIIIIIIIIII,PPPPPP */
+	roli r3, r2, 7	/* r3 = BBB,IIIIIIIIIIIIIIII,PPPPPP,AAAAA,BB */
+	roli r4, r3, 3	/* r4 = IIIIIIIIIIIIIIII,PPPPPP,AAAAA,BBBBB */
+	roli r5, r4, 2	/* r5 = IIIIIIIIIIIIII,PPPPPP,AAAAA,BBBBB,II */
+	srai r4, r4, 16	/* r4 = (sign-extended) IMM16 */
+	roli r6, r5, 5	/* r6 = XXXX,NNNNN,PPPPPP,AAAAA,BBBBB,CCCCC,XX */
+	andi r2, r2, 0x3f	/* r2 = 00000000000000000000000000,PPPPPP */
+	andi r3, r3, 0x7c	/* r3 = 0000000000000000000000000,AAAAA,00 */
+	andi r5, r5, 0x7c	/* r5 = 0000000000000000000000000,BBBBB,00 */
+	andi r6, r6, 0x7c	/* r6 = 0000000000000000000000000,CCCCC,00 */
+
+	/* Now
+	* r2 = OP
+	* r3 = 4*A
+	* r4 = IMM16 (sign extended)
+	* r5 = 4*B
+	* r6 = 4*C
+	*/
+
+	/*
+	* Get the operands.
+	*
+	* It is necessary to check for muli because it uses an I-type
+	* instruction format, while the other instructions are have an R-type
+	* format.
+	*
+	*  Prepare for either multiplication or division loop.
+	*  They both loop 32 times.
+	*/
+	movi r14, 32
+
+	add  r3, r3, sp		/* r3 = address of A-operand. */
+	ldw  r3, 0(r3)		/* r3 = A-operand. */
+	movi r7, 0x24		/* muli opcode (I-type instruction format) */
+	beq r2, r7, mul_immed /* muli doesn't use the B register as a source */
+
+	add  r5, r5, sp		/* r5 = address of B-operand. */
+	ldw  r5, 0(r5)		/* r5 = B-operand. */
+				/* r4 = SSSSSSSSSSSSSSSS,-----IMM16------ */
+				/* IMM16 not needed, align OPX portion */
+				/* r4 = SSSSSSSSSSSSSSSS,CCCCC,-OPX--,00000 */
+	srli r4, r4, 5		/* r4 = 00000,SSSSSSSSSSSSSSSS,CCCCC,-OPX-- */
+	andi r4, r4, 0x3f	/* r4 = 00000000000000000000000000,-OPX-- */
+
+	/* Now
+	* r2 = OP
+	* r3 = src1
+	* r5 = src2
+	* r4 = OPX (no longer can be muli)
+	* r6 = 4*C
+	*/
+
+
+	/*
+	*  Multiply or Divide?
+	*/
+	andi r7, r4, 0x02	/* For R-type multiply instructions,
+				   OPX & 0x02 != 0 */
+	bne r7, zero, multiply
+
+
+	/* DIVISION
+	*
+	* Divide an unsigned dividend by an unsigned divisor using
+	* a shift-and-subtract algorithm.  The example below shows
+	* 43 div 7 = 6 for 8-bit integers.  This classic algorithm uses a
+	* single register to store both the dividend and the quotient,
+	* allowing both values to be shifted with a single instruction.
+	*
+	*                               remainder dividend:quotient
+	*                               --------- -----------------
+	*   initialize                   00000000     00101011:
+	*   shift                        00000000     0101011:_
+	*   remainder >= divisor? no     00000000     0101011:0
+	*   shift                        00000000     101011:0_
+	*   remainder >= divisor? no     00000000     101011:00
+	*   shift                        00000001     01011:00_
+	*   remainder >= divisor? no     00000001     01011:000
+	*   shift                        00000010     1011:000_
+	*   remainder >= divisor? no     00000010     1011:0000
+	*   shift                        00000101     011:0000_
+	*   remainder >= divisor? no     00000101     011:00000
+	*   shift                        00001010     11:00000_
+	*   remainder >= divisor? yes    00001010     11:000001
+	*       remainder -= divisor   - 00000111
+	*                              ----------
+	*                                00000011     11:000001
+	*   shift                        00000111     1:000001_
+	*   remainder >= divisor? yes    00000111     1:0000011
+	*       remainder -= divisor   - 00000111
+	*                              ----------
+	*                                00000000     1:0000011
+	*   shift                        00000001     :0000011_
+	*   remainder >= divisor? no     00000001     :00000110
+	*
+	* The quotient is 00000110.
+	*/
+
+divide:
+	/*
+	*  Prepare for division by assuming the result
+	*  is unsigned, and storing its "sign" as 0.
+	*/
+	movi r17, 0
+
+
+	/* Which division opcode? */
+	xori r7, r4, 0x25		/* OPX of div */
+	bne r7, zero, unsigned_division
+
+
+	/*
+	*  OPX is div.  Determine and store the sign of the quotient.
+	*  Then take the absolute value of both operands.
+	*/
+	xor r17, r3, r5		/* MSB contains sign of quotient */
+	bge r3,zero,dividend_is_nonnegative
+	sub r3, zero, r3	/* -r3 */
+dividend_is_nonnegative:
+	bge r5, zero, divisor_is_nonnegative
+	sub r5, zero, r5	/* -r5 */
+divisor_is_nonnegative:
+
+
+unsigned_division:
+	/* Initialize the unsigned-division loop. */
+	movi r13, 0	/* remainder = 0 */
+
+	/* Now
+	* r3 = dividend : quotient
+	* r4 = 0x25 for div, 0x24 for divu
+	* r5 = divisor
+	* r13 = remainder
+	* r14 = loop counter (already initialized to 32)
+	* r17 = MSB contains sign of quotient
+	*/
+
+
+	/*
+	*   for (count = 32; count > 0; --count)
+	*   {
+	*/
+divide_loop:
+
+	/*
+	*       Division:
+	*
+	*       (remainder:dividend:quotient) <<= 1;
+	*/
+	slli r13, r13, 1
+	cmplt r7, r3, zero	/* r7 = MSB of r3 */
+	or r13, r13, r7
+	slli r3, r3, 1
+
+
+	/*
+	*       if (remainder >= divisor)
+	*       {
+	*           set LSB of quotient
+	*           remainder -= divisor;
+	*       }
+	*/
+	bltu r13, r5, div_skip
+	ori r3, r3, 1
+	sub r13, r13, r5
+div_skip:
+
+	/*
+	*   }
+	*/
+	subi r14, r14, 1
+	bne r14, zero, divide_loop
+
+
+	/* Now
+	* r3 = quotient
+	* r4 = 0x25 for div, 0x24 for divu
+	* r6 = 4*C
+	* r17 = MSB contains sign of quotient
+	*/
+
+
+	/*
+	*  Conditionally negate signed quotient.  If quotient is unsigned,
+	*  the sign already is initialized to 0.
+	*/
+	bge r17, zero, quotient_is_nonnegative
+	sub r3, zero, r3		/* -r3 */
+	quotient_is_nonnegative:
+
+
+	/*
+	*  Final quotient is in r3.
+	*/
+	add r6, r6, sp
+	stw r3, 0(r6)	/* write quotient to stack */
+	br restore_registers
+
+
+
+
+	/* MULTIPLICATION
+	*
+	* A "product" is the number that one gets by summing a "multiplicand"
+	* several times.  The "multiplier" specifies the number of copies of the
+	* multiplicand that are summed.
+	*
+	* Actual multiplication algorithms don't use repeated addition, however.
+	* Shift-and-add algorithms get the same answer as repeated addition, and
+	* they are faster.  To compute the lower half of a product (pppp below)
+	* one shifts the product left before adding in each of the partial
+	* products (a * mmmm) through (d * mmmm).
+	*
+	* To compute the upper half of a product (PPPP below), one adds in the
+	* partial products (d * mmmm) through (a * mmmm), each time following
+	* the add by a right shift of the product.
+	*
+	*     mmmm
+	*   * abcd
+	*   ------
+	*     ####  = d * mmmm
+	*    ####   = c * mmmm
+	*   ####    = b * mmmm
+	*  ####     = a * mmmm
+	* --------
+	* PPPPpppp
+	*
+	* The example above shows 4 partial products.  Computing actual Nios II
+	* products requires 32 partials.
+	*
+	* It is possible to compute the result of mulxsu from the result of
+	* mulxuu because the only difference between the results of these two
+	* opcodes is the value of the partial product associated with the sign
+	* bit of rA.
+	*
+	*   mulxsu = mulxuu - (rA < 0) ? rB : 0;
+	*
+	* It is possible to compute the result of mulxss from the result of
+	* mulxsu because the only difference between the results of these two
+	* opcodes is the value of the partial product associated with the sign
+	* bit of rB.
+	*
+	*   mulxss = mulxsu - (rB < 0) ? rA : 0;
+	*
+	*/
+
+mul_immed:
+	/* Opcode is muli.  Change it into mul for remainder of algorithm. */
+	mov r6, r5		/* Field B is dest register, not field C. */
+	mov r5, r4		/* Field IMM16 is src2, not field B. */
+	movi r4, 0x27		/* OPX of mul is 0x27 */
+
+multiply:
+	/* Initialize the multiplication loop. */
+	movi r9, 0	/* mul_product    = 0 */
+	movi r10, 0	/* mulxuu_product = 0 */
+	mov r11, r5	/* save original multiplier for mulxsu and mulxss */
+	mov r12, r5	/* mulxuu_multiplier (will be shifted) */
+	movi r16, 1	/* used to create "rori B,A,1" from "ror B,A,r16" */
+
+	/* Now
+	* r3 = multiplicand
+	* r5 = mul_multiplier
+	* r6 = 4 * dest_register (used later as offset to sp)
+	* r7 = temp
+	* r9 = mul_product
+	* r10 = mulxuu_product
+	* r11 = original multiplier
+	* r12 = mulxuu_multiplier
+	* r14 = loop counter (already initialized)
+	* r16 = 1
+	*/
+
+
+	/*
+	*   for (count = 32; count > 0; --count)
+	*   {
+	*/
+multiply_loop:
+
+	/*
+	*       mul_product <<= 1;
+	*       lsb = multiplier & 1;
+	*/
+	slli r9, r9, 1
+	andi r7, r12, 1
+
+	/*
+	*       if (lsb == 1)
+	*       {
+	*           mulxuu_product += multiplicand;
+	*       }
+	*/
+	beq r7, zero, mulx_skip
+	add r10, r10, r3
+	cmpltu r7, r10, r3 /* Save the carry from the MSB of mulxuu_product. */
+	ror r7, r7, r16	/* r7 = 0x80000000 on carry, or else 0x00000000 */
+mulx_skip:
+
+	/*
+	*       if (MSB of mul_multiplier == 1)
+	*       {
+	*           mul_product += multiplicand;
+	*       }
+	*/
+	bge r5, zero, mul_skip
+	add r9, r9, r3
+mul_skip:
+
+	/*
+	*       mulxuu_product >>= 1;           logical shift
+	*       mul_multiplier <<= 1;           done with MSB
+	*       mulx_multiplier >>= 1;          done with LSB
+	*/
+	srli r10, r10, 1
+	or r10, r10, r7		/* OR in the saved carry bit. */
+	slli r5, r5, 1
+	srli r12, r12, 1
+
+
+	/*
+	*   }
+	*/
+	subi r14, r14, 1
+	bne r14, zero, multiply_loop
+
+
+	/*
+	*  Multiply emulation loop done.
+	*/
+
+	/* Now
+	* r3 = multiplicand
+	* r4 = OPX
+	* r6 = 4 * dest_register (used later as offset to sp)
+	* r7 = temp
+	* r9 = mul_product
+	* r10 = mulxuu_product
+	* r11 = original multiplier
+	*/
+
+
+	/* Calculate address for result from 4 * dest_register */
+	add r6, r6, sp
+
+
+	/*
+	* Select/compute the result based on OPX.
+	*/
+
+
+	/* OPX == mul?  Then store. */
+	xori r7, r4, 0x27
+	beq r7, zero, store_product
+
+	/* It's one of the mulx.. opcodes.  Move over the result. */
+	mov r9, r10
+
+	/* OPX == mulxuu?  Then store. */
+	xori r7, r4, 0x07
+	beq r7, zero, store_product
+
+	/* Compute mulxsu
+	 *
+	 * mulxsu = mulxuu - (rA < 0) ? rB : 0;
+	 */
+	bge r3, zero, mulxsu_skip
+	sub r9, r9, r11
+mulxsu_skip:
+
+	/* OPX == mulxsu?  Then store. */
+	xori r7, r4, 0x17
+	beq r7, zero, store_product
+
+	/* Compute mulxss
+	 *
+	 * mulxss = mulxsu - (rB < 0) ? rA : 0;
+	 */
+	bge r11,zero,mulxss_skip
+	sub r9, r9, r3
+mulxss_skip:
+	/* At this point, assume that OPX is mulxss, so store*/
+
+
+store_product:
+	stw r9, 0(r6)
+
+
+restore_registers:
+			/* No need to restore r0. */
+	ldw r5, 100(sp)
+	wrctl estatus, r5
+
+	ldw r1, 4(sp)
+	ldw r2, 8(sp)
+	ldw r3, 12(sp)
+	ldw r4, 16(sp)
+	ldw r5, 20(sp)
+	ldw r6, 24(sp)
+	ldw r7, 28(sp)
+	ldw r8, 32(sp)
+	ldw r9, 36(sp)
+	ldw r10, 40(sp)
+	ldw r11, 44(sp)
+	ldw r12, 48(sp)
+	ldw r13, 52(sp)
+	ldw r14, 56(sp)
+	ldw r15, 60(sp)
+	ldw r16, 64(sp)
+	ldw r17, 68(sp)
+	ldw r18, 72(sp)
+	ldw r19, 76(sp)
+	ldw r20, 80(sp)
+	ldw r21, 84(sp)
+	ldw r22, 88(sp)
+	ldw r23, 92(sp)
+			/* Does not need to restore et */
+	ldw gp, 104(sp)
+
+	ldw fp, 112(sp)
+	ldw ea, 116(sp)
+	ldw ra, 120(sp)
+	ldw sp, 108(sp)	/* last restore sp */
+	eret
+
+.set at
+.set break
diff --git a/arch/nios2/kernel/irq.c b/arch/nios2/kernel/irq.c
new file mode 100644
index 000000000..6b7890e5f
--- /dev/null
+++ b/arch/nios2/kernel/irq.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * based on irq.c from m68k which is:
+ *
+ * Copyright (C) 2007 Greg Ungerer <gerg@snapgear.com>
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+
+static u32 ienable;
+
+asmlinkage void do_IRQ(int hwirq, struct pt_regs *regs)
+{
+	struct pt_regs *oldregs = set_irq_regs(regs);
+
+	irq_enter();
+	generic_handle_domain_irq(NULL, hwirq);
+	irq_exit();
+
+	set_irq_regs(oldregs);
+}
+
+static void chip_unmask(struct irq_data *d)
+{
+	ienable |= (1 << d->hwirq);
+	WRCTL(CTL_IENABLE, ienable);
+}
+
+static void chip_mask(struct irq_data *d)
+{
+	ienable &= ~(1 << d->hwirq);
+	WRCTL(CTL_IENABLE, ienable);
+}
+
+static struct irq_chip m_irq_chip = {
+	.name		= "NIOS2-INTC",
+	.irq_unmask	= chip_unmask,
+	.irq_mask	= chip_mask,
+};
+
+static int irq_map(struct irq_domain *h, unsigned int virq,
+				irq_hw_number_t hw_irq_num)
+{
+	irq_set_chip_and_handler(virq, &m_irq_chip, handle_level_irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops irq_ops = {
+	.map	= irq_map,
+	.xlate	= irq_domain_xlate_onecell,
+};
+
+void __init init_IRQ(void)
+{
+	struct irq_domain *domain;
+	struct device_node *node;
+
+	node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.0");
+	if (!node)
+		node = of_find_compatible_node(NULL, NULL, "altr,nios2-1.1");
+
+	BUG_ON(!node);
+
+	domain = irq_domain_add_linear(node, NIOS2_CPU_NR_IRQS, &irq_ops, NULL);
+	BUG_ON(!domain);
+
+	irq_set_default_host(domain);
+	of_node_put(node);
+	/* Load the initial ienable value */
+	ienable = RDCTL(CTL_IENABLE);
+}
diff --git a/arch/nios2/kernel/kgdb.c b/arch/nios2/kernel/kgdb.c
new file mode 100644
index 000000000..d0963fcb1
--- /dev/null
+++ b/arch/nios2/kernel/kgdb.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Nios2 KGDB support
+ *
+ * Copyright (C) 2015 Altera Corporation
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ *
+ * Based on the code posted by Kazuyasu on the Altera Forum at:
+ * http://www.alteraforum.com/forum/showpost.php?p=77003&postcount=20
+ */
+#include <linux/ptrace.h>
+#include <linux/kgdb.h>
+#include <linux/kdebug.h>
+#include <linux/io.h>
+
+static int wait_for_remote_debugger;
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
+{
+	{ "zero", GDB_SIZEOF_REG, -1 },
+	{ "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, r1) },
+	{ "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r2) },
+	{ "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r3) },
+	{ "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r4) },
+	{ "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r5) },
+	{ "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r6) },
+	{ "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r7) },
+	{ "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r8) },
+	{ "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r9) },
+	{ "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10) },
+	{ "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11) },
+	{ "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12) },
+	{ "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13) },
+	{ "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14) },
+	{ "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15) },
+	{ "r16", GDB_SIZEOF_REG, -1 },
+	{ "r17", GDB_SIZEOF_REG, -1 },
+	{ "r18", GDB_SIZEOF_REG, -1 },
+	{ "r19", GDB_SIZEOF_REG, -1 },
+	{ "r20", GDB_SIZEOF_REG, -1 },
+	{ "r21", GDB_SIZEOF_REG, -1 },
+	{ "r22", GDB_SIZEOF_REG, -1 },
+	{ "r23", GDB_SIZEOF_REG, -1 },
+	{ "et", GDB_SIZEOF_REG, -1 },
+	{ "bt", GDB_SIZEOF_REG, -1 },
+	{ "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp) },
+	{ "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, sp) },
+	{ "fp", GDB_SIZEOF_REG, offsetof(struct pt_regs, fp) },
+	{ "ea", GDB_SIZEOF_REG, -1 },
+	{ "ba", GDB_SIZEOF_REG, -1 },
+	{ "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, ra) },
+	{ "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, ea) },
+	{ "status", GDB_SIZEOF_REG, -1 },
+	{ "estatus", GDB_SIZEOF_REG, offsetof(struct pt_regs, estatus) },
+	{ "bstatus", GDB_SIZEOF_REG, -1 },
+	{ "ienable", GDB_SIZEOF_REG, -1 },
+	{ "ipending", GDB_SIZEOF_REG, -1},
+	{ "cpuid", GDB_SIZEOF_REG, -1 },
+	{ "ctl6", GDB_SIZEOF_REG, -1 },
+	{ "exception", GDB_SIZEOF_REG, -1 },
+	{ "pteaddr", GDB_SIZEOF_REG, -1 },
+	{ "tlbacc", GDB_SIZEOF_REG, -1 },
+	{ "tlbmisc", GDB_SIZEOF_REG, -1 },
+	{ "eccinj", GDB_SIZEOF_REG, -1 },
+	{ "badaddr", GDB_SIZEOF_REG, -1 },
+	{ "config", GDB_SIZEOF_REG, -1 },
+	{ "mpubase", GDB_SIZEOF_REG, -1 },
+	{ "mpuacc", GDB_SIZEOF_REG, -1 },
+};
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+	if (regno >= DBG_MAX_REG_NUM || regno < 0)
+		return NULL;
+
+	if (dbg_reg_def[regno].offset != -1)
+		memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
+		       dbg_reg_def[regno].size);
+	else
+		memset(mem, 0, dbg_reg_def[regno].size);
+
+	return dbg_reg_def[regno].name;
+}
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+	if (regno >= DBG_MAX_REG_NUM || regno < 0)
+		return -EINVAL;
+
+	if (dbg_reg_def[regno].offset != -1)
+		memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
+		       dbg_reg_def[regno].size);
+
+	return 0;
+}
+
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+	memset((char *)gdb_regs, 0, NUMREGBYTES);
+	gdb_regs[GDB_SP] = p->thread.kregs->sp;
+	gdb_regs[GDB_PC] = p->thread.kregs->ea;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+	regs->ea = pc;
+}
+
+int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+				char *remcom_in_buffer, char *remcom_out_buffer,
+				struct pt_regs *regs)
+{
+	char *ptr;
+	unsigned long addr;
+
+	switch (remcom_in_buffer[0]) {
+	case 's':
+	case 'c':
+		/* handle the optional parameters */
+		ptr = &remcom_in_buffer[1];
+		if (kgdb_hex2long(&ptr, &addr))
+			regs->ea = addr;
+
+		return 0;
+	}
+
+	return -1; /* this means that we do not want to exit from the handler */
+}
+
+asmlinkage void kgdb_breakpoint_c(struct pt_regs *regs)
+{
+	/*
+	 * The breakpoint entry code has moved the PC on by 4 bytes, so we must
+	 * move it back.  This could be done on the host but we do it here
+	 */
+	if (!wait_for_remote_debugger)
+		regs->ea -= 4;
+	else	/* pass the first trap 30 code */
+		wait_for_remote_debugger = 0;
+
+	kgdb_handle_exception(30, SIGTRAP, 0, regs);
+}
+
+int kgdb_arch_init(void)
+{
+	wait_for_remote_debugger = 1;
+	return 0;
+}
+
+void kgdb_arch_exit(void)
+{
+	/* Nothing to do */
+}
+
+const struct kgdb_arch arch_kgdb_ops = {
+	/* Breakpoint instruction: trap 30 */
+	.gdb_bpt_instr = { 0xba, 0x6f, 0x3b, 0x00 },
+};
diff --git a/arch/nios2/kernel/misaligned.c b/arch/nios2/kernel/misaligned.c
new file mode 100644
index 000000000..23e0544e1
--- /dev/null
+++ b/arch/nios2/kernel/misaligned.c
@@ -0,0 +1,238 @@
+/*
+ *  linux/arch/nios2/kernel/misaligned.c
+ *
+ *  basic emulation for mis-aligned accesses on the NIOS II cpu
+ *  modelled after the version for arm in arm/alignment.c
+ *
+ *  Brad Parker <brad@heeltoe.com>
+ *  Copyright (C) 2010 Ambient Corporation
+ *  Copyright (c) 2010 Altera Corporation, San Jose, California, USA.
+ *  Copyright (c) 2010 Arrow Electronics, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file COPYING in the main directory of
+ * this archive for more details.
+ */
+
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+
+#include <asm/traps.h>
+#include <asm/unaligned.h>
+
+/* instructions we emulate */
+#define INST_LDHU	0x0b
+#define INST_STH	0x0d
+#define INST_LDH	0x0f
+#define INST_STW	0x15
+#define INST_LDW	0x17
+
+static unsigned int ma_usermode;
+#define UM_WARN		0x01
+#define UM_FIXUP	0x02
+#define UM_SIGNAL	0x04
+#define KM_WARN		0x08
+
+/* see arch/nios2/include/asm/ptrace.h */
+static u8 sys_stack_frame_reg_offset[] = {
+	/* struct pt_regs */
+	8, 9, 10, 11, 12, 13, 14, 15, 1, 2, 3, 4, 5, 6, 7, 0,
+	/* struct switch_stack */
+	16, 17, 18, 19, 20, 21, 22, 23, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+static int reg_offsets[32];
+
+static inline u32 get_reg_val(struct pt_regs *fp, int reg)
+{
+	u8 *p = ((u8 *)fp) + reg_offsets[reg];
+	return *(u32 *)p;
+}
+
+static inline void put_reg_val(struct pt_regs *fp, int reg, u32 val)
+{
+	u8 *p = ((u8 *)fp) + reg_offsets[reg];
+	*(u32 *)p = val;
+}
+
+/*
+ * (mis)alignment handler
+ */
+asmlinkage void handle_unaligned_c(struct pt_regs *fp, int cause)
+{
+	u32 isn, addr, val;
+	int in_kernel;
+	u8 a, b, d0, d1, d2, d3;
+	s16 imm16;
+	unsigned int fault;
+
+	/* back up one instruction */
+	fp->ea -= 4;
+
+	if (fixup_exception(fp)) {
+		return;
+	}
+
+	in_kernel = !user_mode(fp);
+
+	isn = *(unsigned long *)(fp->ea);
+
+	fault = 0;
+
+	/* do fixup if in kernel or mode turned on */
+	if (in_kernel || (ma_usermode & UM_FIXUP)) {
+		/* decompose instruction */
+		a = (isn >> 27) & 0x1f;
+		b = (isn >> 22) & 0x1f;
+		imm16 = (isn >> 6) & 0xffff;
+		addr = get_reg_val(fp, a) + imm16;
+
+		/* do fixup to saved registers */
+		switch (isn & 0x3f) {
+		case INST_LDHU:
+			fault |= __get_user(d0, (u8 *)(addr+0));
+			fault |= __get_user(d1, (u8 *)(addr+1));
+			val = (d1 << 8) | d0;
+			put_reg_val(fp, b, val);
+			break;
+		case INST_STH:
+			val = get_reg_val(fp, b);
+			d1 = val >> 8;
+			d0 = val >> 0;
+			if (in_kernel) {
+				*(u8 *)(addr+0) = d0;
+				*(u8 *)(addr+1) = d1;
+			} else {
+				fault |= __put_user(d0, (u8 *)(addr+0));
+				fault |= __put_user(d1, (u8 *)(addr+1));
+			}
+			break;
+		case INST_LDH:
+			fault |= __get_user(d0, (u8 *)(addr+0));
+			fault |= __get_user(d1, (u8 *)(addr+1));
+			val = (short)((d1 << 8) | d0);
+			put_reg_val(fp, b, val);
+			break;
+		case INST_STW:
+			val = get_reg_val(fp, b);
+			d3 = val >> 24;
+			d2 = val >> 16;
+			d1 = val >> 8;
+			d0 = val >> 0;
+			if (in_kernel) {
+				*(u8 *)(addr+0) = d0;
+				*(u8 *)(addr+1) = d1;
+				*(u8 *)(addr+2) = d2;
+				*(u8 *)(addr+3) = d3;
+			} else {
+				fault |= __put_user(d0, (u8 *)(addr+0));
+				fault |= __put_user(d1, (u8 *)(addr+1));
+				fault |= __put_user(d2, (u8 *)(addr+2));
+				fault |= __put_user(d3, (u8 *)(addr+3));
+			}
+			break;
+		case INST_LDW:
+			fault |= __get_user(d0, (u8 *)(addr+0));
+			fault |= __get_user(d1, (u8 *)(addr+1));
+			fault |= __get_user(d2, (u8 *)(addr+2));
+			fault |= __get_user(d3, (u8 *)(addr+3));
+			val = (d3 << 24) | (d2 << 16) | (d1 << 8) | d0;
+			put_reg_val(fp, b, val);
+			break;
+		}
+	}
+
+	addr = RDCTL(CTL_BADADDR);
+	cause >>= 2;
+
+	if (fault) {
+		if (in_kernel) {
+			pr_err("fault during kernel misaligned fixup @ %#lx; addr 0x%08x; isn=0x%08x\n",
+				fp->ea, (unsigned int)addr,
+				(unsigned int)isn);
+		} else {
+			pr_err("fault during user misaligned fixup @ %#lx; isn=%08x addr=0x%08x sp=0x%08lx pid=%d\n",
+				fp->ea,
+				(unsigned int)isn, addr, fp->sp,
+				current->pid);
+
+			_exception(SIGSEGV, fp, SEGV_MAPERR, fp->ea);
+			return;
+		}
+	}
+
+	/*
+	 * kernel mode -
+	 *  note exception and skip bad instruction (return)
+	 */
+	if (in_kernel) {
+		fp->ea += 4;
+
+		if (ma_usermode & KM_WARN) {
+			pr_err("kernel unaligned access @ %#lx; BADADDR 0x%08x; cause=%d, isn=0x%08x\n",
+				fp->ea,
+				(unsigned int)addr, cause,
+				(unsigned int)isn);
+			/* show_regs(fp); */
+		}
+
+		return;
+	}
+
+	/*
+	 * user mode -
+	 *  possibly warn,
+	 *  possibly send SIGBUS signal to process
+	 */
+	if (ma_usermode & UM_WARN) {
+		pr_err("user unaligned access @ %#lx; isn=0x%08lx ea=0x%08lx ra=0x%08lx sp=0x%08lx\n",
+			(unsigned long)addr, (unsigned long)isn,
+			fp->ea, fp->ra, fp->sp);
+	}
+
+	if (ma_usermode & UM_SIGNAL)
+		_exception(SIGBUS, fp, BUS_ADRALN, fp->ea);
+	else
+		fp->ea += 4;	/* else advance */
+}
+
+static void __init misaligned_calc_reg_offsets(void)
+{
+	int i, r, offset;
+
+	/* pre-calc offsets of registers on sys call stack frame */
+	offset = 0;
+
+	/* struct pt_regs */
+	for (i = 0; i < 16; i++) {
+		r = sys_stack_frame_reg_offset[i];
+		reg_offsets[r] = offset;
+		offset += 4;
+	}
+
+	/* struct switch_stack */
+	offset = -sizeof(struct switch_stack);
+	for (i = 16; i < 32; i++) {
+		r = sys_stack_frame_reg_offset[i];
+		reg_offsets[r] = offset;
+		offset += 4;
+	}
+}
+
+
+static int __init misaligned_init(void)
+{
+	/* default mode - silent fix */
+	ma_usermode = UM_FIXUP | KM_WARN;
+
+	misaligned_calc_reg_offsets();
+
+	return 0;
+}
+
+fs_initcall(misaligned_init);
diff --git a/arch/nios2/kernel/module.c b/arch/nios2/kernel/module.c
new file mode 100644
index 000000000..76e0a42d6
--- /dev/null
+++ b/arch/nios2/kernel/module.c
@@ -0,0 +1,137 @@
+/*
+ * Kernel module support for Nios II.
+ *
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *   Written by Wentao Xu <xuwentao@microtronix.com>
+ * Copyright (C) 2001, 2003 Rusty Russell
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file COPYING in the main directory of this
+ * archive for more details.
+ */
+
+#include <linux/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+
+#include <asm/cacheflush.h>
+
+/*
+ * Modules should NOT be allocated with kmalloc for (obvious) reasons.
+ * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
+ * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
+ * addresses in 0xc0000000)
+ */
+void *module_alloc(unsigned long size)
+{
+	if (size == 0)
+		return NULL;
+	return kmalloc(size, GFP_KERNEL);
+}
+
+/* Free memory returned from module_alloc */
+void module_memfree(void *module_region)
+{
+	kfree(module_region);
+}
+
+int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
+			unsigned int symindex, unsigned int relsec,
+			struct module *mod)
+{
+	unsigned int i;
+	Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+
+	pr_debug("Applying relocate section %u to %u\n", relsec,
+		 sechdrs[relsec].sh_info);
+
+	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
+		/* This is where to make the change */
+		uint32_t word;
+		uint32_t *loc
+			= ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+			   + rela[i].r_offset);
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
+		Elf32_Sym *sym
+			= ((Elf32_Sym *)sechdrs[symindex].sh_addr
+				+ ELF32_R_SYM(rela[i].r_info));
+		uint32_t v = sym->st_value + rela[i].r_addend;
+
+		pr_debug("reltype %d 0x%x name:<%s>\n",
+			ELF32_R_TYPE(rela[i].r_info),
+			rela[i].r_offset, strtab + sym->st_name);
+
+		switch (ELF32_R_TYPE(rela[i].r_info)) {
+		case R_NIOS2_NONE:
+			break;
+		case R_NIOS2_BFD_RELOC_32:
+			*loc += v;
+			break;
+		case R_NIOS2_PCREL16:
+			v -= (uint32_t)loc + 4;
+			if ((int32_t)v > 0x7fff ||
+				(int32_t)v < -(int32_t)0x8000) {
+				pr_err("module %s: relocation overflow\n",
+					mod->name);
+				return -ENOEXEC;
+			}
+			word = *loc;
+			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
+				(word & 0x3f);
+			break;
+		case R_NIOS2_CALL26:
+			if (v & 3) {
+				pr_err("module %s: dangerous relocation\n",
+					mod->name);
+				return -ENOEXEC;
+			}
+			if ((v >> 28) != ((uint32_t)loc >> 28)) {
+				pr_err("module %s: relocation overflow\n",
+					mod->name);
+				return -ENOEXEC;
+			}
+			*loc = (*loc & 0x3f) | ((v >> 2) << 6);
+			break;
+		case R_NIOS2_HI16:
+			word = *loc;
+			*loc = ((((word >> 22) << 16) |
+				((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
+			break;
+		case R_NIOS2_LO16:
+			word = *loc;
+			*loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
+					(word & 0x3f);
+			break;
+		case R_NIOS2_HIADJ16:
+			{
+				Elf32_Addr word2;
+
+				word = *loc;
+				word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
+				*loc = ((((word >> 22) << 16) | word2) << 6) |
+						(word & 0x3f);
+			}
+			break;
+
+		default:
+			pr_err("module %s: Unknown reloc: %u\n",
+				mod->name, ELF32_R_TYPE(rela[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+
+	return 0;
+}
+
+int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
+			struct module *me)
+{
+	flush_cache_all();
+	return 0;
+}
diff --git a/arch/nios2/kernel/nios2_ksyms.c b/arch/nios2/kernel/nios2_ksyms.c
new file mode 100644
index 000000000..54f7b23df
--- /dev/null
+++ b/arch/nios2/kernel/nios2_ksyms.c
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2004 Microtronix Datacom Ltd
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file COPYING in the main directory of this
+ * archive for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/string.h>
+#include <linux/pgtable.h>
+
+#include <asm/cacheflush.h>
+
+/* string functions */
+
+EXPORT_SYMBOL(memcpy);
+EXPORT_SYMBOL(memset);
+EXPORT_SYMBOL(memmove);
+
+/* memory management */
+
+EXPORT_SYMBOL(empty_zero_page);
+EXPORT_SYMBOL(flush_icache_range);
+
+/*
+ * libgcc functions - functions that are used internally by the
+ * compiler...  (prototypes are not correct though, but that
+ * doesn't really matter since they're not versioned).
+ */
+#define DECLARE_EXPORT(name)	extern void name(void); EXPORT_SYMBOL(name)
+
+DECLARE_EXPORT(__gcc_bcmp);
+DECLARE_EXPORT(__divsi3);
+DECLARE_EXPORT(__moddi3);
+DECLARE_EXPORT(__modsi3);
+DECLARE_EXPORT(__udivmoddi4);
+DECLARE_EXPORT(__udivsi3);
+DECLARE_EXPORT(__umoddi3);
+DECLARE_EXPORT(__umodsi3);
+DECLARE_EXPORT(__muldi3);
+DECLARE_EXPORT(__ucmpdi2);
+DECLARE_EXPORT(__lshrdi3);
+DECLARE_EXPORT(__ashldi3);
+DECLARE_EXPORT(__ashrdi3);
diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c
new file mode 100644
index 000000000..29593b985
--- /dev/null
+++ b/arch/nios2/kernel/process.c
@@ -0,0 +1,269 @@
+/*
+ * Architecture-dependent parts of process handling.
+ *
+ * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2009 Wind River Systems Inc
+ *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ * Copyright (C) 2004 Microtronix Datacom Ltd
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/mm_types.h>
+#include <linux/tick.h>
+#include <linux/uaccess.h>
+
+#include <asm/unistd.h>
+#include <asm/traps.h>
+#include <asm/cpuinfo.h>
+
+asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
+
+void (*pm_power_off)(void) = NULL;
+EXPORT_SYMBOL(pm_power_off);
+
+void arch_cpu_idle(void)
+{
+	raw_local_irq_enable();
+}
+
+/*
+ * The development boards have no way to pull a board reset. Just jump to the
+ * cpu reset address and let the boot loader or the code in head.S take care of
+ * resetting peripherals.
+ */
+void machine_restart(char *__unused)
+{
+	pr_notice("Machine restart (%08x)...\n", cpuinfo.reset_addr);
+	local_irq_disable();
+	__asm__ __volatile__ (
+	"jmp	%0\n\t"
+	:
+	: "r" (cpuinfo.reset_addr)
+	: "r4");
+}
+
+void machine_halt(void)
+{
+	pr_notice("Machine halt...\n");
+	local_irq_disable();
+	for (;;)
+		;
+}
+
+/*
+ * There is no way to power off the development boards. So just spin for now. If
+ * we ever have a way of resetting a board using a GPIO we should add that here.
+ */
+void machine_power_off(void)
+{
+	pr_notice("Machine power off...\n");
+	local_irq_disable();
+	for (;;)
+		;
+}
+
+void show_regs(struct pt_regs *regs)
+{
+	pr_notice("\n");
+	show_regs_print_info(KERN_DEFAULT);
+
+	pr_notice("r1: %08lx r2: %08lx r3: %08lx r4: %08lx\n",
+		regs->r1,  regs->r2,  regs->r3,  regs->r4);
+
+	pr_notice("r5: %08lx r6: %08lx r7: %08lx r8: %08lx\n",
+		regs->r5,  regs->r6,  regs->r7,  regs->r8);
+
+	pr_notice("r9: %08lx r10: %08lx r11: %08lx r12: %08lx\n",
+		regs->r9,  regs->r10, regs->r11, regs->r12);
+
+	pr_notice("r13: %08lx r14: %08lx r15: %08lx\n",
+		regs->r13, regs->r14, regs->r15);
+
+	pr_notice("ra: %08lx fp:  %08lx sp: %08lx gp: %08lx\n",
+		regs->ra,  regs->fp,  regs->sp,  regs->gp);
+
+	pr_notice("ea: %08lx estatus: %08lx\n",
+		regs->ea,  regs->estatus);
+}
+
+void flush_thread(void)
+{
+}
+
+int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
+{
+	unsigned long clone_flags = args->flags;
+	unsigned long usp = args->stack;
+	unsigned long tls = args->tls;
+	struct pt_regs *childregs = task_pt_regs(p);
+	struct pt_regs *regs;
+	struct switch_stack *stack;
+	struct switch_stack *childstack =
+		((struct switch_stack *)childregs) - 1;
+
+	if (unlikely(args->fn)) {
+		memset(childstack, 0,
+			sizeof(struct switch_stack) + sizeof(struct pt_regs));
+
+		childstack->r16 = (unsigned long) args->fn;
+		childstack->r17 = (unsigned long) args->fn_arg;
+		childstack->ra = (unsigned long) ret_from_kernel_thread;
+		childregs->estatus = STATUS_PIE;
+		childregs->sp = (unsigned long) childstack;
+
+		p->thread.ksp = (unsigned long) childstack;
+		p->thread.kregs = childregs;
+		return 0;
+	}
+
+	regs = current_pt_regs();
+	*childregs = *regs;
+	childregs->r2 = 0;	/* Set the return value for the child. */
+	childregs->r7 = 0;
+
+	stack = ((struct switch_stack *) regs) - 1;
+	*childstack = *stack;
+	childstack->ra = (unsigned long)ret_from_fork;
+	p->thread.kregs = childregs;
+	p->thread.ksp = (unsigned long) childstack;
+
+	if (usp)
+		childregs->sp = usp;
+
+	/* Initialize tls register. */
+	if (clone_flags & CLONE_SETTLS)
+		childstack->r23 = tls;
+
+	return 0;
+}
+
+/*
+ *	Generic dumping code. Used for panic and debug.
+ */
+void dump(struct pt_regs *fp)
+{
+	unsigned long	*sp;
+	unsigned char	*tp;
+	int		i;
+
+	pr_emerg("\nCURRENT PROCESS:\n\n");
+	pr_emerg("COMM=%s PID=%d\n", current->comm, current->pid);
+
+	if (current->mm) {
+		pr_emerg("TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n",
+			(int) current->mm->start_code,
+			(int) current->mm->end_code,
+			(int) current->mm->start_data,
+			(int) current->mm->end_data,
+			(int) current->mm->end_data,
+			(int) current->mm->brk);
+		pr_emerg("USER-STACK=%08x  KERNEL-STACK=%08x\n\n",
+			(int) current->mm->start_stack,
+			(int)(((unsigned long) current) + THREAD_SIZE));
+	}
+
+	pr_emerg("PC: %08lx\n", fp->ea);
+	pr_emerg("SR: %08lx    SP: %08lx\n",
+		(long) fp->estatus, (long) fp);
+
+	pr_emerg("r1: %08lx    r2: %08lx    r3: %08lx\n",
+		fp->r1, fp->r2, fp->r3);
+
+	pr_emerg("r4: %08lx    r5: %08lx    r6: %08lx    r7: %08lx\n",
+		fp->r4, fp->r5, fp->r6, fp->r7);
+	pr_emerg("r8: %08lx    r9: %08lx    r10: %08lx    r11: %08lx\n",
+		fp->r8, fp->r9, fp->r10, fp->r11);
+	pr_emerg("r12: %08lx  r13: %08lx    r14: %08lx    r15: %08lx\n",
+		fp->r12, fp->r13, fp->r14, fp->r15);
+	pr_emerg("or2: %08lx   ra: %08lx     fp: %08lx    sp: %08lx\n",
+		fp->orig_r2, fp->ra, fp->fp, fp->sp);
+	pr_emerg("\nUSP: %08x   TRAPFRAME: %08x\n",
+		(unsigned int) fp->sp, (unsigned int) fp);
+
+	pr_emerg("\nCODE:");
+	tp = ((unsigned char *) fp->ea) - 0x20;
+	for (sp = (unsigned long *) tp, i = 0; (i < 0x40);  i += 4) {
+		if ((i % 0x10) == 0)
+			pr_emerg("\n%08x: ", (int) (tp + i));
+		pr_emerg("%08x ", (int) *sp++);
+	}
+	pr_emerg("\n");
+
+	pr_emerg("\nKERNEL STACK:");
+	tp = ((unsigned char *) fp) - 0x40;
+	for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) {
+		if ((i % 0x10) == 0)
+			pr_emerg("\n%08x: ", (int) (tp + i));
+		pr_emerg("%08x ", (int) *sp++);
+	}
+	pr_emerg("\n");
+	pr_emerg("\n");
+
+	pr_emerg("\nUSER STACK:");
+	tp = (unsigned char *) (fp->sp - 0x10);
+	for (sp = (unsigned long *) tp, i = 0; (i < 0x80); i += 4) {
+		if ((i % 0x10) == 0)
+			pr_emerg("\n%08x: ", (int) (tp + i));
+		pr_emerg("%08x ", (int) *sp++);
+	}
+	pr_emerg("\n\n");
+}
+
+unsigned long __get_wchan(struct task_struct *p)
+{
+	unsigned long fp, pc;
+	unsigned long stack_page;
+	int count = 0;
+
+	stack_page = (unsigned long)p;
+	fp = ((struct switch_stack *)p->thread.ksp)->fp;	/* ;dgt2 */
+	do {
+		if (fp < stack_page+sizeof(struct task_struct) ||
+			fp >= 8184+stack_page)	/* ;dgt2;tmp */
+			return 0;
+		pc = ((unsigned long *)fp)[1];
+		if (!in_sched_functions(pc))
+			return pc;
+		fp = *(unsigned long *) fp;
+	} while (count++ < 16);		/* ;dgt2;tmp */
+	return 0;
+}
+
+/*
+ * Do necessary setup to start up a newly executed thread.
+ * Will startup in user mode (status_extension = 0).
+ */
+void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
+{
+	memset((void *) regs, 0, sizeof(struct pt_regs));
+	regs->estatus = ESTATUS_EPIE | ESTATUS_EU;
+	regs->ea = pc;
+	regs->sp = sp;
+}
+
+asmlinkage int nios2_clone(unsigned long clone_flags, unsigned long newsp,
+			   int __user *parent_tidptr, int __user *child_tidptr,
+			   unsigned long tls)
+{
+	struct kernel_clone_args args = {
+		.flags		= (lower_32_bits(clone_flags) & ~CSIGNAL),
+		.pidfd		= parent_tidptr,
+		.child_tid	= child_tidptr,
+		.parent_tid	= parent_tidptr,
+		.exit_signal	= (lower_32_bits(clone_flags) & CSIGNAL),
+		.stack		= newsp,
+		.tls		= tls,
+	};
+
+	return kernel_clone(&args);
+}
diff --git a/arch/nios2/kernel/prom.c b/arch/nios2/kernel/prom.c
new file mode 100644
index 000000000..8d98af5c7
--- /dev/null
+++ b/arch/nios2/kernel/prom.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Device tree support
+ *
+ * Copyright (C) 2013, 2015 Altera Corporation
+ * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * Based on MIPS support for CONFIG_OF device tree support
+ *
+ * Copyright (C) 2010 Cisco Systems Inc. <dediao@cisco.com>
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/io.h>
+
+#include <asm/sections.h>
+
+void __init early_init_devtree(void *params)
+{
+	__be32 *dtb = (u32 *)__dtb_start;
+#if defined(CONFIG_NIOS2_DTB_AT_PHYS_ADDR)
+	if (be32_to_cpup((__be32 *)CONFIG_NIOS2_DTB_PHYS_ADDR) ==
+		 OF_DT_HEADER) {
+		params = (void *)CONFIG_NIOS2_DTB_PHYS_ADDR;
+		early_init_dt_scan(params);
+		return;
+	}
+#endif
+	if (be32_to_cpu((__be32) *dtb) == OF_DT_HEADER)
+		params = (void *)__dtb_start;
+
+	early_init_dt_scan(params);
+}
diff --git a/arch/nios2/kernel/ptrace.c b/arch/nios2/kernel/ptrace.c
new file mode 100644
index 000000000..cd62f3107
--- /dev/null
+++ b/arch/nios2/kernel/ptrace.c
@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2014 Altera Corporation
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file COPYING in the main directory of this
+ * archive for more details.
+ */
+
+#include <linux/elf.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+#include <linux/regset.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/uaccess.h>
+#include <linux/user.h>
+
+static int genregs_get(struct task_struct *target,
+		       const struct user_regset *regset,
+		       struct membuf to)
+{
+	const struct pt_regs *regs = task_pt_regs(target);
+	const struct switch_stack *sw = (struct switch_stack *)regs - 1;
+
+	membuf_zero(&to, 4); // R0
+	membuf_write(&to, &regs->r1, 7 * 4); // R1..R7
+	membuf_write(&to, &regs->r8, 8 * 4); // R8..R15
+	membuf_write(&to, sw, 8 * 4); // R16..R23
+	membuf_zero(&to, 2 * 4); /* et and bt */
+	membuf_store(&to, regs->gp);
+	membuf_store(&to, regs->sp);
+	membuf_store(&to, regs->fp);
+	membuf_store(&to, regs->ea);
+	membuf_zero(&to, 4); // PTR_BA
+	membuf_store(&to, regs->ra);
+	membuf_store(&to, regs->ea); /* use ea for PC */
+	return membuf_zero(&to, (NUM_PTRACE_REG - PTR_PC) * 4);
+}
+
+/*
+ * Set the thread state from a regset passed in via ptrace
+ */
+static int genregs_set(struct task_struct *target,
+		       const struct user_regset *regset,
+		       unsigned int pos, unsigned int count,
+		       const void *kbuf, const void __user *ubuf)
+{
+	struct pt_regs *regs = task_pt_regs(target);
+	const struct switch_stack *sw = (struct switch_stack *)regs - 1;
+	int ret = 0;
+
+#define REG_IGNORE_RANGE(START, END)		\
+	if (!ret)					\
+		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, \
+			START * 4, (END * 4) + 4);
+
+#define REG_IN_ONE(PTR, LOC)	\
+	if (!ret)			\
+		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
+			(void *)(PTR), LOC * 4, (LOC * 4) + 4);
+
+#define REG_IN_RANGE(PTR, START, END)	\
+	if (!ret)				\
+		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
+			(void *)(PTR), START * 4, (END * 4) + 4);
+
+	REG_IGNORE_RANGE(PTR_R0, PTR_R0);
+	REG_IN_RANGE(&regs->r1, PTR_R1, PTR_R7);
+	REG_IN_RANGE(&regs->r8, PTR_R8, PTR_R15);
+	REG_IN_RANGE(sw, PTR_R16, PTR_R23);
+	REG_IGNORE_RANGE(PTR_R24, PTR_R25); /* et and bt */
+	REG_IN_ONE(&regs->gp, PTR_GP);
+	REG_IN_ONE(&regs->sp, PTR_SP);
+	REG_IN_ONE(&regs->fp, PTR_FP);
+	REG_IN_ONE(&regs->ea, PTR_EA);
+	REG_IGNORE_RANGE(PTR_BA, PTR_BA);
+	REG_IN_ONE(&regs->ra, PTR_RA);
+	REG_IN_ONE(&regs->ea, PTR_PC); /* use ea for PC */
+	if (!ret)
+		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+					 PTR_STATUS * 4, -1);
+
+	return ret;
+}
+
+/*
+ * Define the register sets available on Nios2 under Linux
+ */
+enum nios2_regset {
+	REGSET_GENERAL,
+};
+
+static const struct user_regset nios2_regsets[] = {
+	[REGSET_GENERAL] = {
+		.core_note_type = NT_PRSTATUS,
+		.n = NUM_PTRACE_REG,
+		.size = sizeof(unsigned long),
+		.align = sizeof(unsigned long),
+		.regset_get = genregs_get,
+		.set = genregs_set,
+	}
+};
+
+static const struct user_regset_view nios2_user_view = {
+	.name = "nios2",
+	.e_machine = ELF_ARCH,
+	.ei_osabi = ELF_OSABI,
+	.regsets = nios2_regsets,
+	.n = ARRAY_SIZE(nios2_regsets)
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &nios2_user_view;
+}
+
+void ptrace_disable(struct task_struct *child)
+{
+
+}
+
+long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
+		 unsigned long data)
+{
+	return ptrace_request(child, request, addr, data);
+}
+
+asmlinkage int do_syscall_trace_enter(void)
+{
+	int ret = 0;
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		ret = ptrace_report_syscall_entry(task_pt_regs(current));
+
+	return ret;
+}
+
+asmlinkage void do_syscall_trace_exit(void)
+{
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		ptrace_report_syscall_exit(task_pt_regs(current), 0);
+}
diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c
new file mode 100644
index 000000000..40bc8fb75
--- /dev/null
+++ b/arch/nios2/kernel/setup.c
@@ -0,0 +1,197 @@
+/*
+ * Nios2-specific parts of system setup
+ *
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ * Copyright (C) 2001 Vic Phillips <vic@microtronix.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/console.h>
+#include <linux/memblock.h>
+#include <linux/initrd.h>
+#include <linux/of_fdt.h>
+#include <linux/screen_info.h>
+
+#include <asm/mmu_context.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/cpuinfo.h>
+
+unsigned long memory_start;
+EXPORT_SYMBOL(memory_start);
+
+unsigned long memory_end;
+EXPORT_SYMBOL(memory_end);
+
+static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+					0, 0, 0, 0, 0, 0,
+					0};
+
+#ifdef CONFIG_VT
+struct screen_info screen_info;
+#endif
+
+/* Copy a short hook instruction sequence to the exception address */
+static inline void copy_exception_handler(unsigned int addr)
+{
+	unsigned int start = (unsigned int) exception_handler_hook;
+	volatile unsigned int tmp = 0;
+
+	if (start == addr) {
+		/* The CPU exception address already points to the handler. */
+		return;
+	}
+
+	__asm__ __volatile__ (
+		"ldw	%2,0(%0)\n"
+		"stw	%2,0(%1)\n"
+		"ldw	%2,4(%0)\n"
+		"stw	%2,4(%1)\n"
+		"ldw	%2,8(%0)\n"
+		"stw	%2,8(%1)\n"
+		"flushd	0(%1)\n"
+		"flushd	4(%1)\n"
+		"flushd	8(%1)\n"
+		"flushi %1\n"
+		"addi	%1,%1,4\n"
+		"flushi %1\n"
+		"addi	%1,%1,4\n"
+		"flushi %1\n"
+		"flushp\n"
+		: /* no output registers */
+		: "r" (start), "r" (addr), "r" (tmp)
+		: "memory"
+	);
+}
+
+/* Copy the fast TLB miss handler */
+static inline void copy_fast_tlb_miss_handler(unsigned int addr)
+{
+	unsigned int start = (unsigned int) fast_handler;
+	unsigned int end = (unsigned int) fast_handler_end;
+	volatile unsigned int tmp = 0;
+
+	__asm__ __volatile__ (
+		"1:\n"
+		"	ldw	%3,0(%0)\n"
+		"	stw	%3,0(%1)\n"
+		"	flushd	0(%1)\n"
+		"	flushi	%1\n"
+		"	flushp\n"
+		"	addi	%0,%0,4\n"
+		"	addi	%1,%1,4\n"
+		"	bne	%0,%2,1b\n"
+		: /* no output registers */
+		: "r" (start), "r" (addr), "r" (end), "r" (tmp)
+		: "memory"
+	);
+}
+
+/*
+ * save args passed from u-boot, called from head.S
+ *
+ * @r4: NIOS magic
+ * @r5: initrd start
+ * @r6: initrd end or fdt
+ * @r7: kernel command line
+ */
+asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
+				       unsigned r7)
+{
+	unsigned dtb_passed = 0;
+	char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
+
+#if defined(CONFIG_NIOS2_PASS_CMDLINE)
+	if (r4 == 0x534f494e) { /* r4 is magic NIOS */
+#if defined(CONFIG_BLK_DEV_INITRD)
+		if (r5) { /* initramfs */
+			initrd_start = r5;
+			initrd_end = r6;
+		}
+#endif /* CONFIG_BLK_DEV_INITRD */
+		dtb_passed = r6;
+
+		if (r7)
+			strlcpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
+	}
+#endif
+
+	early_init_devtree((void *)dtb_passed);
+
+#ifndef CONFIG_CMDLINE_FORCE
+	if (cmdline_passed[0])
+		strlcpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
+#ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
+	else
+		strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#endif
+#endif
+
+	parse_early_param();
+}
+
+static void __init find_limits(unsigned long *min, unsigned long *max_low,
+			       unsigned long *max_high)
+{
+	*max_low = PFN_DOWN(memblock_get_current_limit());
+	*min = PFN_UP(memblock_start_of_DRAM());
+	*max_high = PFN_DOWN(memblock_end_of_DRAM());
+}
+
+void __init setup_arch(char **cmdline_p)
+{
+	console_verbose();
+
+	memory_start = memblock_start_of_DRAM();
+	memory_end = memblock_end_of_DRAM();
+
+	setup_initial_init_mm(_stext, _etext, _edata, _end);
+	init_task.thread.kregs = &fake_regs;
+
+	/* Keep a copy of command line */
+	*cmdline_p = boot_command_line;
+
+	find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
+	max_mapnr = max_low_pfn;
+
+	memblock_reserve(__pa_symbol(_stext), _end - _stext);
+#ifdef CONFIG_BLK_DEV_INITRD
+	if (initrd_start) {
+		memblock_reserve(virt_to_phys((void *)initrd_start),
+				initrd_end - initrd_start);
+	}
+#endif /* CONFIG_BLK_DEV_INITRD */
+
+	early_init_fdt_reserve_self();
+	early_init_fdt_scan_reserved_mem();
+
+	unflatten_and_copy_device_tree();
+
+	setup_cpuinfo();
+
+	copy_exception_handler(cpuinfo.exception_addr);
+
+	mmu_init();
+
+	copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
+
+	/*
+	 * Initialize MMU context handling here because data from cpuinfo is
+	 * needed for this.
+	 */
+	mmu_context_init();
+
+	/*
+	 * get kmalloc into gear
+	 */
+	paging_init();
+}
diff --git a/arch/nios2/kernel/signal.c b/arch/nios2/kernel/signal.c
new file mode 100644
index 000000000..a5b93a30c
--- /dev/null
+++ b/arch/nios2/kernel/signal.c
@@ -0,0 +1,328 @@
+/*
+ * Copyright (C) 2013-2014 Altera Corporation
+ * Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/uaccess.h>
+#include <linux/unistd.h>
+#include <linux/personality.h>
+#include <linux/resume_user_mode.h>
+
+#include <asm/ucontext.h>
+#include <asm/cacheflush.h>
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+/*
+ * Do a signal return; undo the signal stack.
+ *
+ * Keep the return code on the stack quadword aligned!
+ * That makes the cache flush below easier.
+ */
+
+struct rt_sigframe {
+	struct siginfo info;
+	struct ucontext uc;
+};
+
+static inline int rt_restore_ucontext(struct pt_regs *regs,
+					struct switch_stack *sw,
+					struct ucontext __user *uc, int *pr2)
+{
+	int temp;
+	unsigned long __user *gregs = uc->uc_mcontext.gregs;
+	int err;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	err = __get_user(temp, &uc->uc_mcontext.version);
+	if (temp != MCONTEXT_VERSION)
+		goto badframe;
+	/* restore passed registers */
+	err |= __get_user(regs->r1, &gregs[0]);
+	err |= __get_user(regs->r2, &gregs[1]);
+	err |= __get_user(regs->r3, &gregs[2]);
+	err |= __get_user(regs->r4, &gregs[3]);
+	err |= __get_user(regs->r5, &gregs[4]);
+	err |= __get_user(regs->r6, &gregs[5]);
+	err |= __get_user(regs->r7, &gregs[6]);
+	err |= __get_user(regs->r8, &gregs[7]);
+	err |= __get_user(regs->r9, &gregs[8]);
+	err |= __get_user(regs->r10, &gregs[9]);
+	err |= __get_user(regs->r11, &gregs[10]);
+	err |= __get_user(regs->r12, &gregs[11]);
+	err |= __get_user(regs->r13, &gregs[12]);
+	err |= __get_user(regs->r14, &gregs[13]);
+	err |= __get_user(regs->r15, &gregs[14]);
+	err |= __get_user(sw->r16, &gregs[15]);
+	err |= __get_user(sw->r17, &gregs[16]);
+	err |= __get_user(sw->r18, &gregs[17]);
+	err |= __get_user(sw->r19, &gregs[18]);
+	err |= __get_user(sw->r20, &gregs[19]);
+	err |= __get_user(sw->r21, &gregs[20]);
+	err |= __get_user(sw->r22, &gregs[21]);
+	err |= __get_user(sw->r23, &gregs[22]);
+	/* gregs[23] is handled below */
+	err |= __get_user(sw->fp, &gregs[24]);  /* Verify, should this be
+							settable */
+	err |= __get_user(sw->gp, &gregs[25]);  /* Verify, should this be
+							settable */
+
+	err |= __get_user(temp, &gregs[26]);  /* Not really necessary no user
+							settable bits */
+	err |= __get_user(regs->ea, &gregs[27]);
+
+	err |= __get_user(regs->ra, &gregs[23]);
+	err |= __get_user(regs->sp, &gregs[28]);
+
+	regs->orig_r2 = -1;		/* disable syscall checks */
+
+	err |= restore_altstack(&uc->uc_stack);
+	if (err)
+		goto badframe;
+
+	*pr2 = regs->r2;
+	return err;
+
+badframe:
+	return 1;
+}
+
+asmlinkage int do_rt_sigreturn(struct switch_stack *sw)
+{
+	struct pt_regs *regs = (struct pt_regs *)(sw + 1);
+	/* Verify, can we follow the stack back */
+	struct rt_sigframe __user *frame;
+	sigset_t set;
+	int rval;
+
+	frame = (struct rt_sigframe __user *) regs->sp;
+	if (!access_ok(frame, sizeof(*frame)))
+		goto badframe;
+
+	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+		goto badframe;
+
+	set_current_blocked(&set);
+
+	if (rt_restore_ucontext(regs, sw, &frame->uc, &rval))
+		goto badframe;
+
+	return rval;
+
+badframe:
+	force_sig(SIGSEGV);
+	return 0;
+}
+
+static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
+{
+	struct switch_stack *sw = (struct switch_stack *)regs - 1;
+	unsigned long __user *gregs = uc->uc_mcontext.gregs;
+	int err = 0;
+
+	err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
+	err |= __put_user(regs->r1, &gregs[0]);
+	err |= __put_user(regs->r2, &gregs[1]);
+	err |= __put_user(regs->r3, &gregs[2]);
+	err |= __put_user(regs->r4, &gregs[3]);
+	err |= __put_user(regs->r5, &gregs[4]);
+	err |= __put_user(regs->r6, &gregs[5]);
+	err |= __put_user(regs->r7, &gregs[6]);
+	err |= __put_user(regs->r8, &gregs[7]);
+	err |= __put_user(regs->r9, &gregs[8]);
+	err |= __put_user(regs->r10, &gregs[9]);
+	err |= __put_user(regs->r11, &gregs[10]);
+	err |= __put_user(regs->r12, &gregs[11]);
+	err |= __put_user(regs->r13, &gregs[12]);
+	err |= __put_user(regs->r14, &gregs[13]);
+	err |= __put_user(regs->r15, &gregs[14]);
+	err |= __put_user(sw->r16, &gregs[15]);
+	err |= __put_user(sw->r17, &gregs[16]);
+	err |= __put_user(sw->r18, &gregs[17]);
+	err |= __put_user(sw->r19, &gregs[18]);
+	err |= __put_user(sw->r20, &gregs[19]);
+	err |= __put_user(sw->r21, &gregs[20]);
+	err |= __put_user(sw->r22, &gregs[21]);
+	err |= __put_user(sw->r23, &gregs[22]);
+	err |= __put_user(regs->ra, &gregs[23]);
+	err |= __put_user(sw->fp, &gregs[24]);
+	err |= __put_user(sw->gp, &gregs[25]);
+	err |= __put_user(regs->ea, &gregs[27]);
+	err |= __put_user(regs->sp, &gregs[28]);
+	return err;
+}
+
+static inline void __user *get_sigframe(struct ksignal *ksig,
+					struct pt_regs *regs,
+					size_t frame_size)
+{
+	unsigned long usp;
+
+	/* Default to using normal stack.  */
+	usp = regs->sp;
+
+	/* This is the X/Open sanctioned signal stack switching.  */
+	usp = sigsp(usp, ksig);
+
+	/* Verify, is it 32 or 64 bit aligned */
+	return (void __user *)((usp - frame_size) & -8UL);
+}
+
+static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
+			  struct pt_regs *regs)
+{
+	struct rt_sigframe __user *frame;
+	int err = 0;
+
+	frame = get_sigframe(ksig, regs, sizeof(*frame));
+
+	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+	/* Create the ucontext.  */
+	err |= __put_user(0, &frame->uc.uc_flags);
+	err |= __put_user(0, &frame->uc.uc_link);
+	err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
+	err |= rt_setup_ucontext(&frame->uc, regs);
+	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+	if (err)
+		goto give_sigsegv;
+
+	/* Set up to return from userspace; jump to fixed address sigreturn
+	   trampoline on kuser page.  */
+	regs->ra = (unsigned long) (0x1044);
+
+	/* Set up registers for signal handler */
+	regs->sp = (unsigned long) frame;
+	regs->r4 = (unsigned long) ksig->sig;
+	regs->r5 = (unsigned long) &frame->info;
+	regs->r6 = (unsigned long) &frame->uc;
+	regs->ea = (unsigned long) ksig->ka.sa.sa_handler;
+	return 0;
+
+give_sigsegv:
+	force_sigsegv(ksig->sig);
+	return -EFAULT;
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+	int ret;
+	sigset_t *oldset = sigmask_to_save();
+
+	/* set up the stack frame */
+	ret = setup_rt_frame(ksig, oldset, regs);
+
+	signal_setup_done(ret, ksig, 0);
+}
+
+static int do_signal(struct pt_regs *regs)
+{
+	unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
+	int restart = 0;
+	struct ksignal ksig;
+
+	current->thread.kregs = regs;
+
+	/*
+	 * If we were from a system call, check for system call restarting...
+	 */
+	if (regs->orig_r2 >= 0 && regs->r1) {
+		continue_addr = regs->ea;
+		restart_addr = continue_addr - 4;
+		retval = regs->r2;
+
+		/*
+		 * Prepare for system call restart. We do this here so that a
+		 * debugger will see the already changed PC.
+		 */
+		switch (retval) {
+		case ERESTART_RESTARTBLOCK:
+			restart = -2;
+			fallthrough;
+		case ERESTARTNOHAND:
+		case ERESTARTSYS:
+		case ERESTARTNOINTR:
+			restart++;
+			regs->r2 = regs->orig_r2;
+			regs->r7 = regs->orig_r7;
+			regs->ea = restart_addr;
+			break;
+		}
+		regs->orig_r2 = -1;
+	}
+
+	if (get_signal(&ksig)) {
+		/* handler */
+		if (unlikely(restart && regs->ea == restart_addr)) {
+			if (retval == ERESTARTNOHAND ||
+			    retval == ERESTART_RESTARTBLOCK ||
+			     (retval == ERESTARTSYS
+				&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
+				regs->r2 = EINTR;
+				regs->r7 = 1;
+				regs->ea = continue_addr;
+			}
+		}
+		handle_signal(&ksig, regs);
+		return 0;
+	}
+
+	/*
+	 * No handler present
+	 */
+	if (unlikely(restart) && regs->ea == restart_addr) {
+		regs->ea = continue_addr;
+		regs->r2 = __NR_restart_syscall;
+	}
+
+	/*
+	* If there's no signal to deliver, we just put the saved sigmask back.
+	*/
+	restore_saved_sigmask();
+
+	return restart;
+}
+
+asmlinkage int do_notify_resume(struct pt_regs *regs)
+{
+	/*
+	 * We want the common case to go fast, which is why we may in certain
+	 * cases get here from kernel mode. Just return without doing anything
+	 * if so.
+	 */
+	if (!user_mode(regs))
+		return 0;
+
+	if (test_thread_flag(TIF_SIGPENDING) ||
+	    test_thread_flag(TIF_NOTIFY_SIGNAL)) {
+		int restart = do_signal(regs);
+
+		if (unlikely(restart)) {
+			/*
+			 * Restart without handlers.
+			 * Deal with it without leaving
+			 * the kernel space.
+			 */
+			return restart;
+		}
+	} else if (test_thread_flag(TIF_NOTIFY_RESUME))
+		resume_user_mode_work(regs);
+
+	return 0;
+}
diff --git a/arch/nios2/kernel/sys_nios2.c b/arch/nios2/kernel/sys_nios2.c
new file mode 100644
index 000000000..b1ca85699
--- /dev/null
+++ b/arch/nios2/kernel/sys_nios2.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+
+#include <asm/cacheflush.h>
+#include <asm/traps.h>
+
+/* sys_cacheflush -- flush the processor cache. */
+asmlinkage int sys_cacheflush(unsigned long addr, unsigned long len,
+				unsigned int op)
+{
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+
+	if (len == 0)
+		return 0;
+
+	/* We only support op 0 now, return error if op is non-zero.*/
+	if (op)
+		return -EINVAL;
+
+	/* Check for overflow */
+	if (addr + len < addr)
+		return -EFAULT;
+
+	if (mmap_read_lock_killable(mm))
+		return -EINTR;
+
+	/*
+	 * Verify that the specified address region actually belongs
+	 * to this process.
+	 */
+	vma = find_vma(mm, addr);
+	if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end) {
+		mmap_read_unlock(mm);
+		return -EFAULT;
+	}
+
+	flush_cache_range(vma, addr, addr + len);
+
+	mmap_read_unlock(mm);
+	return 0;
+}
+
+asmlinkage int sys_getpagesize(void)
+{
+	return PAGE_SIZE;
+}
diff --git a/arch/nios2/kernel/syscall_table.c b/arch/nios2/kernel/syscall_table.c
new file mode 100644
index 000000000..c2875a6dd
--- /dev/null
+++ b/arch/nios2/kernel/syscall_table.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright Altera Corporation (C) 2013. All rights reserved
+ */
+
+#include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/unistd.h>
+
+#include <asm/syscalls.h>
+
+#undef __SYSCALL
+#define __SYSCALL(nr, call) [nr] = (call),
+
+void *sys_call_table[__NR_syscalls] = {
+	[0 ... __NR_syscalls-1] = sys_ni_syscall,
+#include <asm/unistd.h>
+};
diff --git a/arch/nios2/kernel/time.c b/arch/nios2/kernel/time.c
new file mode 100644
index 000000000..54467d008
--- /dev/null
+++ b/arch/nios2/kernel/time.c
@@ -0,0 +1,359 @@
+/*
+ * Copyright (C) 2013-2014 Altera Corporation
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#define ALTR_TIMER_COMPATIBLE		"altr,timer-1.0"
+
+#define ALTERA_TIMER_STATUS_REG	0
+#define ALTERA_TIMER_CONTROL_REG	4
+#define ALTERA_TIMER_PERIODL_REG	8
+#define ALTERA_TIMER_PERIODH_REG	12
+#define ALTERA_TIMER_SNAPL_REG		16
+#define ALTERA_TIMER_SNAPH_REG		20
+
+#define ALTERA_TIMER_CONTROL_ITO_MSK	(0x1)
+#define ALTERA_TIMER_CONTROL_CONT_MSK	(0x2)
+#define ALTERA_TIMER_CONTROL_START_MSK	(0x4)
+#define ALTERA_TIMER_CONTROL_STOP_MSK	(0x8)
+
+struct nios2_timer {
+	void __iomem *base;
+	unsigned long freq;
+};
+
+struct nios2_clockevent_dev {
+	struct nios2_timer timer;
+	struct clock_event_device ced;
+};
+
+struct nios2_clocksource {
+	struct nios2_timer timer;
+	struct clocksource cs;
+};
+
+static inline struct nios2_clockevent_dev *
+	to_nios2_clkevent(struct clock_event_device *evt)
+{
+	return container_of(evt, struct nios2_clockevent_dev, ced);
+}
+
+static inline struct nios2_clocksource *
+	to_nios2_clksource(struct clocksource *cs)
+{
+	return container_of(cs, struct nios2_clocksource, cs);
+}
+
+static u16 timer_readw(struct nios2_timer *timer, u32 offs)
+{
+	return readw(timer->base + offs);
+}
+
+static void timer_writew(struct nios2_timer *timer, u16 val, u32 offs)
+{
+	writew(val, timer->base + offs);
+}
+
+static inline unsigned long read_timersnapshot(struct nios2_timer *timer)
+{
+	unsigned long count;
+
+	timer_writew(timer, 0, ALTERA_TIMER_SNAPL_REG);
+	count = timer_readw(timer, ALTERA_TIMER_SNAPH_REG) << 16 |
+		timer_readw(timer, ALTERA_TIMER_SNAPL_REG);
+
+	return count;
+}
+
+static u64 nios2_timer_read(struct clocksource *cs)
+{
+	struct nios2_clocksource *nios2_cs = to_nios2_clksource(cs);
+	unsigned long flags;
+	u32 count;
+
+	local_irq_save(flags);
+	count = read_timersnapshot(&nios2_cs->timer);
+	local_irq_restore(flags);
+
+	/* Counter is counting down */
+	return ~count;
+}
+
+static struct nios2_clocksource nios2_cs = {
+	.cs = {
+		.name	= "nios2-clksrc",
+		.rating	= 250,
+		.read	= nios2_timer_read,
+		.mask	= CLOCKSOURCE_MASK(32),
+		.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+	},
+};
+
+cycles_t get_cycles(void)
+{
+	/* Only read timer if it has been initialized */
+	if (nios2_cs.timer.base)
+		return nios2_timer_read(&nios2_cs.cs);
+	return 0;
+}
+EXPORT_SYMBOL(get_cycles);
+
+static void nios2_timer_start(struct nios2_timer *timer)
+{
+	u16 ctrl;
+
+	ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
+	ctrl |= ALTERA_TIMER_CONTROL_START_MSK;
+	timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+}
+
+static void nios2_timer_stop(struct nios2_timer *timer)
+{
+	u16 ctrl;
+
+	ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
+	ctrl |= ALTERA_TIMER_CONTROL_STOP_MSK;
+	timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+}
+
+static void nios2_timer_config(struct nios2_timer *timer, unsigned long period,
+			       bool periodic)
+{
+	u16 ctrl;
+
+	/* The timer's actual period is one cycle greater than the value
+	 * stored in the period register. */
+	 period--;
+
+	ctrl = timer_readw(timer, ALTERA_TIMER_CONTROL_REG);
+	/* stop counter */
+	timer_writew(timer, ctrl | ALTERA_TIMER_CONTROL_STOP_MSK,
+		ALTERA_TIMER_CONTROL_REG);
+
+	/* write new count */
+	timer_writew(timer, period, ALTERA_TIMER_PERIODL_REG);
+	timer_writew(timer, period >> 16, ALTERA_TIMER_PERIODH_REG);
+
+	ctrl |= ALTERA_TIMER_CONTROL_START_MSK | ALTERA_TIMER_CONTROL_ITO_MSK;
+	if (periodic)
+		ctrl |= ALTERA_TIMER_CONTROL_CONT_MSK;
+	else
+		ctrl &= ~ALTERA_TIMER_CONTROL_CONT_MSK;
+	timer_writew(timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+}
+
+static int nios2_timer_set_next_event(unsigned long delta,
+	struct clock_event_device *evt)
+{
+	struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+
+	nios2_timer_config(&nios2_ced->timer, delta, false);
+
+	return 0;
+}
+
+static int nios2_timer_shutdown(struct clock_event_device *evt)
+{
+	struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+	struct nios2_timer *timer = &nios2_ced->timer;
+
+	nios2_timer_stop(timer);
+	return 0;
+}
+
+static int nios2_timer_set_periodic(struct clock_event_device *evt)
+{
+	unsigned long period;
+	struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+	struct nios2_timer *timer = &nios2_ced->timer;
+
+	period = DIV_ROUND_UP(timer->freq, HZ);
+	nios2_timer_config(timer, period, true);
+	return 0;
+}
+
+static int nios2_timer_resume(struct clock_event_device *evt)
+{
+	struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+	struct nios2_timer *timer = &nios2_ced->timer;
+
+	nios2_timer_start(timer);
+	return 0;
+}
+
+irqreturn_t timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = (struct clock_event_device *) dev_id;
+	struct nios2_clockevent_dev *nios2_ced = to_nios2_clkevent(evt);
+
+	/* Clear the interrupt condition */
+	timer_writew(&nios2_ced->timer, 0, ALTERA_TIMER_STATUS_REG);
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static int __init nios2_timer_get_base_and_freq(struct device_node *np,
+				void __iomem **base, u32 *freq)
+{
+	*base = of_iomap(np, 0);
+	if (!*base) {
+		pr_crit("Unable to map reg for %pOFn\n", np);
+		return -ENXIO;
+	}
+
+	if (of_property_read_u32(np, "clock-frequency", freq)) {
+		pr_crit("Unable to get %pOFn clock frequency\n", np);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct nios2_clockevent_dev nios2_ce = {
+	.ced = {
+		.name = "nios2-clkevent",
+		.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+		.rating = 250,
+		.shift = 32,
+		.set_next_event = nios2_timer_set_next_event,
+		.set_state_shutdown = nios2_timer_shutdown,
+		.set_state_periodic = nios2_timer_set_periodic,
+		.set_state_oneshot = nios2_timer_shutdown,
+		.tick_resume = nios2_timer_resume,
+	},
+};
+
+static __init int nios2_clockevent_init(struct device_node *timer)
+{
+	void __iomem *iobase;
+	u32 freq;
+	int irq, ret;
+
+	ret = nios2_timer_get_base_and_freq(timer, &iobase, &freq);
+	if (ret)
+		return ret;
+
+	irq = irq_of_parse_and_map(timer, 0);
+	if (!irq) {
+		pr_crit("Unable to parse timer irq\n");
+		return -EINVAL;
+	}
+
+	nios2_ce.timer.base = iobase;
+	nios2_ce.timer.freq = freq;
+
+	nios2_ce.ced.cpumask = cpumask_of(0);
+	nios2_ce.ced.irq = irq;
+
+	nios2_timer_stop(&nios2_ce.timer);
+	/* clear pending interrupt */
+	timer_writew(&nios2_ce.timer, 0, ALTERA_TIMER_STATUS_REG);
+
+	ret = request_irq(irq, timer_interrupt, IRQF_TIMER, timer->name,
+			  &nios2_ce.ced);
+	if (ret) {
+		pr_crit("Unable to setup timer irq\n");
+		return ret;
+	}
+
+	clockevents_config_and_register(&nios2_ce.ced, freq, 1, ULONG_MAX);
+
+	return 0;
+}
+
+static __init int nios2_clocksource_init(struct device_node *timer)
+{
+	unsigned int ctrl;
+	void __iomem *iobase;
+	u32 freq;
+	int ret;
+
+	ret = nios2_timer_get_base_and_freq(timer, &iobase, &freq);
+	if (ret)
+		return ret;
+
+	nios2_cs.timer.base = iobase;
+	nios2_cs.timer.freq = freq;
+
+	ret = clocksource_register_hz(&nios2_cs.cs, freq);
+	if (ret)
+		return ret;
+
+	timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODL_REG);
+	timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODH_REG);
+
+	/* interrupt disable + continuous + start */
+	ctrl = ALTERA_TIMER_CONTROL_CONT_MSK | ALTERA_TIMER_CONTROL_START_MSK;
+	timer_writew(&nios2_cs.timer, ctrl, ALTERA_TIMER_CONTROL_REG);
+
+	/* Calibrate the delay loop directly */
+	lpj_fine = freq / HZ;
+
+	return 0;
+}
+
+/*
+ * The first timer instance will use as a clockevent. If there are two or
+ * more instances, the second one gets used as clocksource and all
+ * others are unused.
+*/
+static int __init nios2_time_init(struct device_node *timer)
+{
+	static int num_called;
+	int ret;
+
+	switch (num_called) {
+	case 0:
+		ret = nios2_clockevent_init(timer);
+		break;
+	case 1:
+		ret = nios2_clocksource_init(timer);
+		break;
+	default:
+		ret = 0;
+		break;
+	}
+
+	num_called++;
+
+	return ret;
+}
+
+void read_persistent_clock64(struct timespec64 *ts)
+{
+	ts->tv_sec = mktime64(2007, 1, 1, 0, 0, 0);
+	ts->tv_nsec = 0;
+}
+
+void __init time_init(void)
+{
+	struct device_node *np;
+	int count = 0;
+
+	for_each_compatible_node(np, NULL,  ALTR_TIMER_COMPATIBLE)
+		count++;
+
+	if (count < 2)
+		panic("%d timer is found, it needs 2 timers in system\n", count);
+
+	timer_probe();
+}
+
+TIMER_OF_DECLARE(nios2_timer, ALTR_TIMER_COMPATIBLE, nios2_time_init);
diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c
new file mode 100644
index 000000000..85ac49d64
--- /dev/null
+++ b/arch/nios2/kernel/traps.c
@@ -0,0 +1,196 @@
+/*
+ * Hardware exception handling
+ *
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ * Copyright (C) 2001 Vic Phillips
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file COPYING in the main directory of this
+ * archive for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+
+#include <asm/traps.h>
+#include <asm/sections.h>
+#include <linux/uaccess.h>
+
+static DEFINE_SPINLOCK(die_lock);
+
+static void _send_sig(int signo, int code, unsigned long addr)
+{
+	force_sig_fault(signo, code, (void __user *) addr);
+}
+
+void die(const char *str, struct pt_regs *regs, long err)
+{
+	console_verbose();
+	spin_lock_irq(&die_lock);
+	pr_warn("Oops: %s, sig: %ld\n", str, err);
+	show_regs(regs);
+	spin_unlock_irq(&die_lock);
+	/*
+	 * make_task_dead() should take care of panic'ing from an interrupt
+	 * context so we don't handle it here
+	 */
+	make_task_dead(err);
+}
+
+void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr)
+{
+	if (!user_mode(regs))
+		die("Exception in kernel mode", regs, signo);
+
+	_send_sig(signo, code, addr);
+}
+
+/*
+ * The show_stack() is external API which we do not use ourselves.
+ */
+
+int kstack_depth_to_print = 48;
+
+void show_stack(struct task_struct *task, unsigned long *stack,
+		const char *loglvl)
+{
+	unsigned long *endstack, addr;
+	int i;
+
+	if (!stack) {
+		if (task)
+			stack = (unsigned long *)task->thread.ksp;
+		else
+			stack = (unsigned long *)&stack;
+	}
+
+	addr = (unsigned long) stack;
+	endstack = (unsigned long *) PAGE_ALIGN(addr);
+
+	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
+	for (i = 0; i < kstack_depth_to_print; i++) {
+		if (stack + 1 > endstack)
+			break;
+		if (i % 8 == 0)
+			printk("%s\n       ", loglvl);
+		printk("%s %08lx", loglvl, *stack++);
+	}
+
+	printk("%s\nCall Trace:", loglvl);
+	i = 0;
+	while (stack + 1 <= endstack) {
+		addr = *stack++;
+		/*
+		 * If the address is either in the text segment of the
+		 * kernel, or in the region which contains vmalloc'ed
+		 * memory, it *may* be the address of a calling
+		 * routine; if so, print it so that someone tracing
+		 * down the cause of the crash will be able to figure
+		 * out the call path that was taken.
+		 */
+		if (((addr >= (unsigned long) _stext) &&
+		     (addr <= (unsigned long) _etext))) {
+			if (i % 4 == 0)
+				pr_emerg("\n       ");
+			printk("%s [<%08lx>]", loglvl, addr);
+			i++;
+		}
+	}
+	printk("%s\n", loglvl);
+}
+
+/* Breakpoint handler */
+asmlinkage void breakpoint_c(struct pt_regs *fp)
+{
+	/*
+	 * The breakpoint entry code has moved the PC on by 4 bytes, so we must
+	 * move it back. This could be done on the host but we do it here
+	 * because monitor.S of JTAG gdbserver does it too.
+	 */
+	fp->ea -= 4;
+	_exception(SIGTRAP, fp, TRAP_BRKPT, fp->ea);
+}
+
+#ifndef CONFIG_NIOS2_ALIGNMENT_TRAP
+/* Alignment exception handler */
+asmlinkage void handle_unaligned_c(struct pt_regs *fp, int cause)
+{
+	unsigned long addr = RDCTL(CTL_BADADDR);
+
+	cause >>= 2;
+	fp->ea -= 4;
+
+	if (fixup_exception(fp))
+		return;
+
+	if (!user_mode(fp)) {
+		pr_alert("Unaligned access from kernel mode, this might be a hardware\n");
+		pr_alert("problem, dump registers and restart the instruction\n");
+		pr_alert("  BADADDR 0x%08lx\n", addr);
+		pr_alert("  cause   %d\n", cause);
+		pr_alert("  op-code 0x%08lx\n", *(unsigned long *)(fp->ea));
+		show_regs(fp);
+		return;
+	}
+
+	_exception(SIGBUS, fp, BUS_ADRALN, addr);
+}
+#endif /* CONFIG_NIOS2_ALIGNMENT_TRAP */
+
+/* Illegal instruction handler */
+asmlinkage void handle_illegal_c(struct pt_regs *fp)
+{
+	fp->ea -= 4;
+	_exception(SIGILL, fp, ILL_ILLOPC, fp->ea);
+}
+
+/* Supervisor instruction handler */
+asmlinkage void handle_supervisor_instr(struct pt_regs *fp)
+{
+	fp->ea -= 4;
+	_exception(SIGILL, fp, ILL_PRVOPC, fp->ea);
+}
+
+/* Division error handler */
+asmlinkage void handle_diverror_c(struct pt_regs *fp)
+{
+	fp->ea -= 4;
+	_exception(SIGFPE, fp, FPE_INTDIV, fp->ea);
+}
+
+/* Unhandled exception handler */
+asmlinkage void unhandled_exception(struct pt_regs *regs, int cause)
+{
+	unsigned long addr = RDCTL(CTL_BADADDR);
+
+	cause /= 4;
+
+	pr_emerg("Unhandled exception #%d in %s mode (badaddr=0x%08lx)\n",
+			cause, user_mode(regs) ? "user" : "kernel", addr);
+
+	regs->ea -= 4;
+	show_regs(regs);
+
+	pr_emerg("opcode: 0x%08lx\n", *(unsigned long *)(regs->ea));
+}
+
+asmlinkage void handle_trap_1_c(struct pt_regs *fp)
+{
+	_send_sig(SIGUSR1, 0, fp->ea);
+}
+
+asmlinkage void handle_trap_2_c(struct pt_regs *fp)
+{
+	_send_sig(SIGUSR2, 0, fp->ea);
+}
+
+asmlinkage void handle_trap_3_c(struct pt_regs *fp)
+{
+	_send_sig(SIGILL, ILL_ILLTRP, fp->ea);
+}
diff --git a/arch/nios2/kernel/vmlinux.lds.S b/arch/nios2/kernel/vmlinux.lds.S
new file mode 100644
index 000000000..126e11474
--- /dev/null
+++ b/arch/nios2/kernel/vmlinux.lds.S
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2009 Thomas Chou <thomas@wytron.com.tw>
+ */
+#include <asm/page.h>
+#include <asm-generic/vmlinux.lds.h>
+#include <asm/cache.h>
+#include <asm/thread_info.h>
+
+OUTPUT_FORMAT("elf32-littlenios2", "elf32-littlenios2", "elf32-littlenios2")
+
+OUTPUT_ARCH(nios)
+ENTRY(_start)	/* Defined in head.S */
+
+jiffies = jiffies_64;
+
+SECTIONS
+{
+	. = CONFIG_NIOS2_MEM_BASE | CONFIG_NIOS2_KERNEL_REGION_BASE;
+
+	_text = .;
+	_stext = .;
+	HEAD_TEXT_SECTION
+	.text : {
+		TEXT_TEXT
+		SCHED_TEXT
+		CPUIDLE_TEXT
+		LOCK_TEXT
+		IRQENTRY_TEXT
+		SOFTIRQENTRY_TEXT
+		KPROBES_TEXT
+	} =0
+	_etext = .;
+
+	.got : {
+		*(.got.plt)
+		*(.igot.plt)
+		*(.got)
+		*(.igot)
+	}
+
+	EXCEPTION_TABLE(L1_CACHE_BYTES)
+
+	. = ALIGN(PAGE_SIZE);
+	__init_begin = .;
+	INIT_TEXT_SECTION(PAGE_SIZE)
+	INIT_DATA_SECTION(PAGE_SIZE)
+	PERCPU_SECTION(L1_CACHE_BYTES)
+	__init_end = .;
+
+	_sdata = .;
+	RO_DATA(PAGE_SIZE)
+	RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
+	_edata = .;
+
+	BSS_SECTION(0, 0, 0)
+	_end = .;
+
+	STABS_DEBUG
+	DWARF_DEBUG
+	ELF_DETAILS
+
+	DISCARDS
+}