/*
 * arch/sh/kernel/process_64.c
 *
 * This file handles the architecture-dependent parts of process handling..
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003 - 2007  Paul Mundt
 * Copyright (C) 2003, 2004 Richard Curnow
 *
 * Started from SH3/4 version:
 *   Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
 *
 *   In turn started from i386 version:
 *     Copyright (C) 1995  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/mm.h>
#include <linux/fs.h>
#include <linux/ptrace.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <asm/syscalls.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#include <asm/fpu.h>
#include <asm/switch_to.h>

struct task_struct *last_task_used_math = NULL;
struct pt_regs fake_swapper_regs = { 0, };

void show_regs(struct pt_regs *regs)
{
        unsigned long long ah, al, bh, bl, ch, cl;

        printk("\n");
        show_regs_print_info(KERN_DEFAULT);

        ah = (regs->pc) >> 32;
        al = (regs->pc) & 0xffffffff;
        bh = (regs->regs[18]) >> 32;
        bl = (regs->regs[18]) & 0xffffffff;
        ch = (regs->regs[15]) >> 32;
        cl = (regs->regs[15]) & 0xffffffff;
        printk("PC  : %08Lx%08Lx LINK: %08Lx%08Lx SP  : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->sr) >> 32;
        al = (regs->sr) & 0xffffffff;
        asm volatile ("getcon   " __TEA ", %0" : "=r" (bh));
        asm volatile ("getcon   " __TEA ", %0" : "=r" (bl));
        bh = (bh) >> 32;
        bl = (bl) & 0xffffffff;
        asm volatile ("getcon   " __KCR0 ", %0" : "=r" (ch));
        asm volatile ("getcon   " __KCR0 ", %0" : "=r" (cl));
        ch = (ch) >> 32;
        cl = (cl) & 0xffffffff;
        printk("SR  : %08Lx%08Lx TEA : %08Lx%08Lx KCR0: %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[0]) >> 32;
        al = (regs->regs[0]) & 0xffffffff;
        bh = (regs->regs[1]) >> 32;
        bl = (regs->regs[1]) & 0xffffffff;
        ch = (regs->regs[2]) >> 32;
        cl = (regs->regs[2]) & 0xffffffff;
        printk("R0  : %08Lx%08Lx R1  : %08Lx%08Lx R2  : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[3]) >> 32;
        al = (regs->regs[3]) & 0xffffffff;
        bh = (regs->regs[4]) >> 32;
        bl = (regs->regs[4]) & 0xffffffff;
        ch = (regs->regs[5]) >> 32;
        cl = (regs->regs[5]) & 0xffffffff;
        printk("R3  : %08Lx%08Lx R4  : %08Lx%08Lx R5  : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[6]) >> 32;
        al = (regs->regs[6]) & 0xffffffff;
        bh = (regs->regs[7]) >> 32;
        bl = (regs->regs[7]) & 0xffffffff;
        ch = (regs->regs[8]) >> 32;
        cl = (regs->regs[8]) & 0xffffffff;
        printk("R6  : %08Lx%08Lx R7  : %08Lx%08Lx R8  : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[9]) >> 32;
        al = (regs->regs[9]) & 0xffffffff;
        bh = (regs->regs[10]) >> 32;
        bl = (regs->regs[10]) & 0xffffffff;
        ch = (regs->regs[11]) >> 32;
        cl = (regs->regs[11]) & 0xffffffff;
        printk("R9  : %08Lx%08Lx R10 : %08Lx%08Lx R11 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[12]) >> 32;
        al = (regs->regs[12]) & 0xffffffff;
        bh = (regs->regs[13]) >> 32;
        bl = (regs->regs[13]) & 0xffffffff;
        ch = (regs->regs[14]) >> 32;
        cl = (regs->regs[14]) & 0xffffffff;
        printk("R12 : %08Lx%08Lx R13 : %08Lx%08Lx R14 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[16]) >> 32;
        al = (regs->regs[16]) & 0xffffffff;
        bh = (regs->regs[17]) >> 32;
        bl = (regs->regs[17]) & 0xffffffff;
        ch = (regs->regs[19]) >> 32;
        cl = (regs->regs[19]) & 0xffffffff;
        printk("R16 : %08Lx%08Lx R17 : %08Lx%08Lx R19 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[20]) >> 32;
        al = (regs->regs[20]) & 0xffffffff;
        bh = (regs->regs[21]) >> 32;
        bl = (regs->regs[21]) & 0xffffffff;
        ch = (regs->regs[22]) >> 32;
        cl = (regs->regs[22]) & 0xffffffff;
        printk("R20 : %08Lx%08Lx R21 : %08Lx%08Lx R22 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[23]) >> 32;
        al = (regs->regs[23]) & 0xffffffff;
        bh = (regs->regs[24]) >> 32;
        bl = (regs->regs[24]) & 0xffffffff;
        ch = (regs->regs[25]) >> 32;
        cl = (regs->regs[25]) & 0xffffffff;
        printk("R23 : %08Lx%08Lx R24 : %08Lx%08Lx R25 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[26]) >> 32;
        al = (regs->regs[26]) & 0xffffffff;
        bh = (regs->regs[27]) >> 32;
        bl = (regs->regs[27]) & 0xffffffff;
        ch = (regs->regs[28]) >> 32;
        cl = (regs->regs[28]) & 0xffffffff;
        printk("R26 : %08Lx%08Lx R27 : %08Lx%08Lx R28 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[29]) >> 32;
        al = (regs->regs[29]) & 0xffffffff;
        bh = (regs->regs[30]) >> 32;
        bl = (regs->regs[30]) & 0xffffffff;
        ch = (regs->regs[31]) >> 32;
        cl = (regs->regs[31]) & 0xffffffff;
        printk("R29 : %08Lx%08Lx R30 : %08Lx%08Lx R31 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[32]) >> 32;
        al = (regs->regs[32]) & 0xffffffff;
        bh = (regs->regs[33]) >> 32;
        bl = (regs->regs[33]) & 0xffffffff;
        ch = (regs->regs[34]) >> 32;
        cl = (regs->regs[34]) & 0xffffffff;
        printk("R32 : %08Lx%08Lx R33 : %08Lx%08Lx R34 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[35]) >> 32;
        al = (regs->regs[35]) & 0xffffffff;
        bh = (regs->regs[36]) >> 32;
        bl = (regs->regs[36]) & 0xffffffff;
        ch = (regs->regs[37]) >> 32;
        cl = (regs->regs[37]) & 0xffffffff;
        printk("R35 : %08Lx%08Lx R36 : %08Lx%08Lx R37 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[38]) >> 32;
        al = (regs->regs[38]) & 0xffffffff;
        bh = (regs->regs[39]) >> 32;
        bl = (regs->regs[39]) & 0xffffffff;
        ch = (regs->regs[40]) >> 32;
        cl = (regs->regs[40]) & 0xffffffff;
        printk("R38 : %08Lx%08Lx R39 : %08Lx%08Lx R40 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[41]) >> 32;
        al = (regs->regs[41]) & 0xffffffff;
        bh = (regs->regs[42]) >> 32;
        bl = (regs->regs[42]) & 0xffffffff;
        ch = (regs->regs[43]) >> 32;
        cl = (regs->regs[43]) & 0xffffffff;
        printk("R41 : %08Lx%08Lx R42 : %08Lx%08Lx R43 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[44]) >> 32;
        al = (regs->regs[44]) & 0xffffffff;
        bh = (regs->regs[45]) >> 32;
        bl = (regs->regs[45]) & 0xffffffff;
        ch = (regs->regs[46]) >> 32;
        cl = (regs->regs[46]) & 0xffffffff;
        printk("R44 : %08Lx%08Lx R45 : %08Lx%08Lx R46 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[47]) >> 32;
        al = (regs->regs[47]) & 0xffffffff;
        bh = (regs->regs[48]) >> 32;
        bl = (regs->regs[48]) & 0xffffffff;
        ch = (regs->regs[49]) >> 32;
        cl = (regs->regs[49]) & 0xffffffff;
        printk("R47 : %08Lx%08Lx R48 : %08Lx%08Lx R49 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[50]) >> 32;
        al = (regs->regs[50]) & 0xffffffff;
        bh = (regs->regs[51]) >> 32;
        bl = (regs->regs[51]) & 0xffffffff;
        ch = (regs->regs[52]) >> 32;
        cl = (regs->regs[52]) & 0xffffffff;
        printk("R50 : %08Lx%08Lx R51 : %08Lx%08Lx R52 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[53]) >> 32;
        al = (regs->regs[53]) & 0xffffffff;
        bh = (regs->regs[54]) >> 32;
        bl = (regs->regs[54]) & 0xffffffff;
        ch = (regs->regs[55]) >> 32;
        cl = (regs->regs[55]) & 0xffffffff;
        printk("R53 : %08Lx%08Lx R54 : %08Lx%08Lx R55 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[56]) >> 32;
        al = (regs->regs[56]) & 0xffffffff;
        bh = (regs->regs[57]) >> 32;
        bl = (regs->regs[57]) & 0xffffffff;
        ch = (regs->regs[58]) >> 32;
        cl = (regs->regs[58]) & 0xffffffff;
        printk("R56 : %08Lx%08Lx R57 : %08Lx%08Lx R58 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[59]) >> 32;
        al = (regs->regs[59]) & 0xffffffff;
        bh = (regs->regs[60]) >> 32;
        bl = (regs->regs[60]) & 0xffffffff;
        ch = (regs->regs[61]) >> 32;
        cl = (regs->regs[61]) & 0xffffffff;
        printk("R59 : %08Lx%08Lx R60 : %08Lx%08Lx R61 : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->regs[62]) >> 32;
        al = (regs->regs[62]) & 0xffffffff;
        bh = (regs->tregs[0]) >> 32;
        bl = (regs->tregs[0]) & 0xffffffff;
        ch = (regs->tregs[1]) >> 32;
        cl = (regs->tregs[1]) & 0xffffffff;
        printk("R62 : %08Lx%08Lx T0  : %08Lx%08Lx T1  : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->tregs[2]) >> 32;
        al = (regs->tregs[2]) & 0xffffffff;
        bh = (regs->tregs[3]) >> 32;
        bl = (regs->tregs[3]) & 0xffffffff;
        ch = (regs->tregs[4]) >> 32;
        cl = (regs->tregs[4]) & 0xffffffff;
        printk("T2  : %08Lx%08Lx T3  : %08Lx%08Lx T4  : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        ah = (regs->tregs[5]) >> 32;
        al = (regs->tregs[5]) & 0xffffffff;
        bh = (regs->tregs[6]) >> 32;
        bl = (regs->tregs[6]) & 0xffffffff;
        ch = (regs->tregs[7]) >> 32;
        cl = (regs->tregs[7]) & 0xffffffff;
        printk("T5  : %08Lx%08Lx T6  : %08Lx%08Lx T7  : %08Lx%08Lx\n",
               ah, al, bh, bl, ch, cl);

        /*
         * If we're in kernel mode, dump the stack too..
         */
        if (!user_mode(regs)) {
                void show_stack(struct task_struct *tsk, unsigned long *sp);
                unsigned long sp = regs->regs[15] & 0xffffffff;
                struct task_struct *tsk = get_current();

                tsk->thread.kregs = regs;

                show_stack(tsk, (unsigned long *)sp);
        }
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(struct task_struct *tsk)
{
        /*
         * See arch/sparc/kernel/process.c for the precedent for doing
         * this -- RPC.
         *
         * The SH-5 FPU save/restore approach relies on
         * last_task_used_math pointing to a live task_struct.  When
         * another task tries to use the FPU for the 1st time, the FPUDIS
         * trap handling (see arch/sh/kernel/cpu/sh5/fpu.c) will save the
         * existing FPU state to the FP regs field within
         * last_task_used_math before re-loading the new task's FPU state
         * (or initialising it if the FPU has been used before).  So if
         * last_task_used_math is stale, and its page has already been
         * re-allocated for another use, the consequences are rather
         * grim. Unless we null it here, there is no other path through
         * which it would get safely nulled.
         */
#ifdef CONFIG_SH_FPU
        if (last_task_used_math == tsk)
                last_task_used_math = NULL;
#endif
}

void flush_thread(void)
{

        /* Called by fs/exec.c (setup_new_exec) to remove traces of a
         * previously running executable. */
#ifdef CONFIG_SH_FPU
        if (last_task_used_math == current) {
                last_task_used_math = NULL;
        }
        /* Force FPU state to be reinitialised after exec */
        clear_used_math();
#endif

        /* if we are a kernel thread, about to change to user thread,
         * update kreg
         */
        if(current->thread.kregs==&fake_swapper_regs) {
          current->thread.kregs =
             ((struct pt_regs *)(THREAD_SIZE + (unsigned long) current) - 1);
          current->thread.uregs = current->thread.kregs;
        }
}

void release_thread(struct task_struct *dead_task)
{
        /* do nothing */
}

/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
#ifdef CONFIG_SH_FPU
        int fpvalid;
        struct task_struct *tsk = current;

        fpvalid = !!tsk_used_math(tsk);
        if (fpvalid) {
                if (current == last_task_used_math) {
                        enable_fpu();
                        save_fpu(tsk);
                        disable_fpu();
                        last_task_used_math = 0;
                        regs->sr |= SR_FD;
                }

                memcpy(fpu, &tsk->thread.xstate->hardfpu, sizeof(*fpu));
        }

        return fpvalid;
#else
        return 0; /* Task didn't use the fpu at all. */
#endif
}
EXPORT_SYMBOL(dump_fpu);

asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(void);

int copy_thread(unsigned long clone_flags, unsigned long usp,
                unsigned long arg, struct task_struct *p)
{
        struct pt_regs *childregs;

#ifdef CONFIG_SH_FPU
        /* can't happen for a kernel thread */
        if (last_task_used_math == current) {
                enable_fpu();
                save_fpu(current);
                disable_fpu();
                last_task_used_math = NULL;
                current_pt_regs()->sr |= SR_FD;
        }
#endif
        /* Copy from sh version */
        childregs = (struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1;
        p->thread.sp = (unsigned long) childregs;

        if (unlikely(p->flags & PF_KTHREAD)) {
                memset(childregs, 0, sizeof(struct pt_regs));
                childregs->regs[2] = (unsigned long)arg;
                childregs->regs[3] = (unsigned long)usp;
                childregs->sr = (1 << 30); /* not user_mode */
                childregs->sr |= SR_FD; /* Invalidate FPU flag */
                p->thread.pc = (unsigned long) ret_from_kernel_thread;
                return 0;
        }
        *childregs = *current_pt_regs();

        /*
         * Sign extend the edited stack.
         * Note that thread.pc and thread.pc will stay
         * 32-bit wide and context switch must take care
         * of NEFF sign extension.
         */
        if (usp)
                childregs->regs[15] = neff_sign_extend(usp);
        p->thread.uregs = childregs;

        childregs->regs[9] = 0; /* Set return value for child */
        childregs->sr |= SR_FD; /* Invalidate FPU flag */

        p->thread.pc = (unsigned long) ret_from_fork;

        return 0;
}

#ifdef CONFIG_FRAME_POINTER
static int in_sh64_switch_to(unsigned long pc)
{
        extern char __sh64_switch_to_end;
        /* For a sleeping task, the PC is somewhere in the middle of the function,
           so we don't have to worry about masking the LSB off */
        return (pc >= (unsigned long) sh64_switch_to) &&
               (pc < (unsigned long) &__sh64_switch_to_end);
}
#endif

unsigned long get_wchan(struct task_struct *p)
{
        unsigned long pc;

        if (!p || p == current || p->state == TASK_RUNNING)
                return 0;

        /*
         * The same comment as on the Alpha applies here, too ...
         */
        pc = thread_saved_pc(p);

#ifdef CONFIG_FRAME_POINTER
        if (in_sh64_switch_to(pc)) {
                unsigned long schedule_fp;
                unsigned long sh64_switch_to_fp;
                unsigned long schedule_caller_pc;

                sh64_switch_to_fp = (long) p->thread.sp;
                /* r14 is saved at offset 4 in the sh64_switch_to frame */
                schedule_fp = *(unsigned long *) (long)(sh64_switch_to_fp + 4);

                /* and the caller of 'schedule' is (currently!) saved at offset 24
                   in the frame of schedule (from disasm) */
                schedule_caller_pc = *(unsigned long *) (long)(schedule_fp + 24);
                return schedule_caller_pc;
        }
#endif
        return pc;
}