// TODO some minor issues
/*
 * 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.
 *
 * Copyright (C) 2001 - 2007  Tensilica Inc.
 *
 * Joe Taylor   <joe@tensilica.com, joetylr@yahoo.com>
 * Chris Zankel <chris@zankel.net>
 * Scott Foehner<sfoehner@yahoo.com>,
 * Kevin Chea
 * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/smp.h>
#include <linux/security.h>
#include <linux/signal.h>

#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ptrace.h>
#include <asm/elf.h>
#include <asm/coprocessor.h>

/*
 * Called by kernel/ptrace.c when detaching to disable single stepping.
 */

void ptrace_disable(struct task_struct *child)
{
        /* Nothing to do.. */
}

int ptrace_getregs(struct task_struct *child, void __user *uregs)
{
        struct pt_regs *regs = task_pt_regs(child);
        xtensa_gregset_t __user *gregset = uregs;
        unsigned long wm = regs->wmask;
        unsigned long wb = regs->windowbase;
        int live, i;

        if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
                return -EIO;

        __put_user(regs->pc, &gregset->pc);
        __put_user(regs->ps & ~(1 << PS_EXCM_BIT), &gregset->ps);
        __put_user(regs->lbeg, &gregset->lbeg);
        __put_user(regs->lend, &gregset->lend);
        __put_user(regs->lcount, &gregset->lcount);
        __put_user(regs->windowstart, &gregset->windowstart);
        __put_user(regs->windowbase, &gregset->windowbase);

        live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;

        for (i = 0; i < live; i++)
                __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
        for (i = XCHAL_NUM_AREGS - (wm >> 4) * 4; i < XCHAL_NUM_AREGS; i++)
                __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));

        return 0;
}

int ptrace_setregs(struct task_struct *child, void __user *uregs)
{
        struct pt_regs *regs = task_pt_regs(child);
        xtensa_gregset_t *gregset = uregs;
        const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;
        unsigned long ps;
        unsigned long wb;

        if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
                return -EIO;

        __get_user(regs->pc, &gregset->pc);
        __get_user(ps, &gregset->ps);
        __get_user(regs->lbeg, &gregset->lbeg);
        __get_user(regs->lend, &gregset->lend);
        __get_user(regs->lcount, &gregset->lcount);
        __get_user(regs->windowstart, &gregset->windowstart);
        __get_user(wb, &gregset->windowbase);

        regs->ps = (regs->ps & ~ps_mask) | (ps & ps_mask) | (1 << PS_EXCM_BIT);

        if (wb >= XCHAL_NUM_AREGS / 4)
                return -EFAULT;

        regs->windowbase = wb;

        if (wb != 0 &&  __copy_from_user(regs->areg + XCHAL_NUM_AREGS - wb * 4,
                                         gregset->a, wb * 16))
                return -EFAULT;

        if (__copy_from_user(regs->areg, gregset->a + wb*4, (WSBITS-wb) * 16))
                return -EFAULT;

        return 0;
}


int ptrace_getxregs(struct task_struct *child, void __user *uregs)
{
        struct pt_regs *regs = task_pt_regs(child);
        struct thread_info *ti = task_thread_info(child);
        elf_xtregs_t __user *xtregs = uregs;
        int ret = 0;

        if (!access_ok(VERIFY_WRITE, uregs, sizeof(elf_xtregs_t)))
                return -EIO;

#if XTENSA_HAVE_COPROCESSORS
        /* Flush all coprocessor registers to memory. */
        coprocessor_flush_all(ti);
        ret |= __copy_to_user(&xtregs->cp0, &ti->xtregs_cp,
                              sizeof(xtregs_coprocessor_t));
#endif
        ret |= __copy_to_user(&xtregs->opt, &regs->xtregs_opt,
                              sizeof(xtregs->opt));
        ret |= __copy_to_user(&xtregs->user,&ti->xtregs_user,
                              sizeof(xtregs->user));

        return ret ? -EFAULT : 0;
}

int ptrace_setxregs(struct task_struct *child, void __user *uregs)
{
        struct thread_info *ti = task_thread_info(child);
        struct pt_regs *regs = task_pt_regs(child);
        elf_xtregs_t *xtregs = uregs;
        int ret = 0;

#if XTENSA_HAVE_COPROCESSORS
        /* Flush all coprocessors before we overwrite them. */
        coprocessor_flush_all(ti);
        coprocessor_release_all(ti);

        ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0, 
                                sizeof(xtregs_coprocessor_t));
#endif
        ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt,
                                sizeof(xtregs->opt));
        ret |= __copy_from_user(&ti->xtregs_user, &xtregs->user,
                                sizeof(xtregs->user));

        return ret ? -EFAULT : 0;
}

int ptrace_peekusr(struct task_struct *child, long regno, long __user *ret)
{
        struct pt_regs *regs;
        unsigned long tmp;

        regs = task_pt_regs(child);
        tmp = 0;  /* Default return value. */

        switch(regno) {

                case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
                        tmp = regs->areg[regno - REG_AR_BASE];
                        break;

                case REG_A_BASE ... REG_A_BASE + 15:
                        tmp = regs->areg[regno - REG_A_BASE];
                        break;

                case REG_PC:
                        tmp = regs->pc;
                        break;

                case REG_PS:
                        /* Note:  PS.EXCM is not set while user task is running;
                         * its being set in regs is for exception handling
                         * convenience.  */
                        tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
                        break;

                case REG_WB:
                        break;          /* tmp = 0 */

                case REG_WS:
                {
                        unsigned long wb = regs->windowbase;
                        unsigned long ws = regs->windowstart;
                        tmp = ((ws>>wb) | (ws<<(WSBITS-wb))) & ((1<<WSBITS)-1);
                        break;
                }
                case REG_LBEG:
                        tmp = regs->lbeg;
                        break;

                case REG_LEND:
                        tmp = regs->lend;
                        break;

                case REG_LCOUNT:
                        tmp = regs->lcount;
                        break;

                case REG_SAR:
                        tmp = regs->sar;
                        break;

                case SYSCALL_NR:
                        tmp = regs->syscall;
                        break;

                default:
                        return -EIO;
        }
        return put_user(tmp, ret);
}

int ptrace_pokeusr(struct task_struct *child, long regno, long val)
{
        struct pt_regs *regs;
        regs = task_pt_regs(child);

        switch (regno) {
                case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
                        regs->areg[regno - REG_AR_BASE] = val;
                        break;

                case REG_A_BASE ... REG_A_BASE + 15:
                        regs->areg[regno - REG_A_BASE] = val;
                        break;

                case REG_PC:
                        regs->pc = val;
                        break;

                case SYSCALL_NR:
                        regs->syscall = val;
                        break;

                default:
                        return -EIO;
        }
        return 0;
}

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
        int ret = -EPERM;

        switch (request) {
        case PTRACE_PEEKTEXT:   /* read word at location addr. */
        case PTRACE_PEEKDATA:
                ret = generic_ptrace_peekdata(child, addr, data);
                break;

        case PTRACE_PEEKUSR:    /* read register specified by addr. */
                ret = ptrace_peekusr(child, addr, (void __user *) data);
                break;

        case PTRACE_POKETEXT:   /* write the word at location addr. */
        case PTRACE_POKEDATA:
                ret = generic_ptrace_pokedata(child, addr, data);
                break;

        case PTRACE_POKEUSR:    /* write register specified by addr. */
                ret = ptrace_pokeusr(child, addr, data);
                break;

        /* continue and stop at next (return from) syscall */

        case PTRACE_SYSCALL:
        case PTRACE_CONT: /* restart after signal. */
        {
                ret = -EIO;
                if (!valid_signal(data))
                        break;
                if (request == PTRACE_SYSCALL)
                        set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
                else
                        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
                child->exit_code = data;
                /* Make sure the single step bit is not set. */
                child->ptrace &= ~PT_SINGLESTEP;
                wake_up_process(child);
                ret = 0;
                break;
        }

        /*
         * make the child exit.  Best I can do is send it a sigkill.
         * perhaps it should be put in the status that it wants to
         * exit.
         */
        case PTRACE_KILL:
                ret = 0;
                if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
                        break;
                child->exit_code = SIGKILL;
                child->ptrace &= ~PT_SINGLESTEP;
                wake_up_process(child);
                break;

        case PTRACE_SINGLESTEP:
                ret = -EIO;
                if (!valid_signal(data))
                        break;
                clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
                child->ptrace |= PT_SINGLESTEP;
                child->exit_code = data;
                wake_up_process(child);
                ret = 0;
                break;

        case PTRACE_GETREGS:
                ret = ptrace_getregs(child, (void __user *) data);
                break;

        case PTRACE_SETREGS:
                ret = ptrace_setregs(child, (void __user *) data);
                break;

        case PTRACE_GETXTREGS:
                ret = ptrace_getxregs(child, (void __user *) data);
                break;

        case PTRACE_SETXTREGS:
                ret = ptrace_setxregs(child, (void __user *) data);
                break;

        default:
                ret = ptrace_request(child, request, addr, data);
                break;
        }

        return ret;
}

void do_syscall_trace(void)
{
        /*
         * The 0x80 provides a way for the tracing parent to distinguish
         * between a syscall stop and SIGTRAP delivery
         */
        ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));

        /*
         * this isn't the same as continuing with a signal, but it will do
         * for normal use.  strace only continues with a signal if the
         * stopping signal is not SIGTRAP.  -brl
         */
        if (current->exit_code) {
                send_sig(current->exit_code, current, 1);
                current->exit_code = 0;
        }
}

void do_syscall_trace_enter(struct pt_regs *regs)
{
        if (test_thread_flag(TIF_SYSCALL_TRACE)
                        && (current->ptrace & PT_PTRACED))
                do_syscall_trace();

#if 0
        if (unlikely(current->audit_context))
                audit_syscall_entry(current, AUDIT_ARCH_XTENSA..);
#endif
}

void do_syscall_trace_leave(struct pt_regs *regs)
{
        if ((test_thread_flag(TIF_SYSCALL_TRACE))
                        && (current->ptrace & PT_PTRACED))
                do_syscall_trace();
}