/*
 * 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(unsigned long clone_flags, unsigned long usp, unsigned long arg,
                struct task_struct *p, unsigned long 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(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
                memset(childstack, 0,
                        sizeof(struct switch_stack) + sizeof(struct pt_regs));

                childstack->r16 = usp;          /* fn */
                childstack->r17 = 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;

        if (!p || p == current || task_is_running(p))
                return 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);
}