/* ptrace.c: Sparc process tracing support.
 *
 * Copyright (C) 1996 David S. Miller (davem@caipfs.rutgers.edu)
 *
 * Based upon code written by Ross Biro, Linus Torvalds, Bob Manson,
 * and David Mosberger.
 *
 * Added Linux support -miguel (weird, eh?, the original code was meant
 * to emulate SunOS).
 */

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

#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#define MAGIC_CONSTANT 0x80000000


/* Returning from ptrace is a bit tricky because the syscall return
 * low level code assumes any value returned which is negative and
 * is a valid errno will mean setting the condition codes to indicate
 * an error return.  This doesn't work, so we have this hook.
 */
static inline void pt_error_return(struct pt_regs *regs, unsigned long error)
{
        regs->u_regs[UREG_I0] = error;
        regs->psr |= PSR_C;
        regs->pc = regs->npc;
        regs->npc += 4;
}

static inline void pt_succ_return(struct pt_regs *regs, unsigned long value)
{
        regs->u_regs[UREG_I0] = value;
        regs->psr &= ~PSR_C;
        regs->pc = regs->npc;
        regs->npc += 4;
}

static void
pt_succ_return_linux(struct pt_regs *regs, unsigned long value, long __user *addr)
{
        if (put_user(value, addr)) {
                pt_error_return(regs, EFAULT);
                return;
        }
        regs->u_regs[UREG_I0] = 0;
        regs->psr &= ~PSR_C;
        regs->pc = regs->npc;
        regs->npc += 4;
}

static void
pt_os_succ_return (struct pt_regs *regs, unsigned long val, long __user *addr)
{
        if (current->personality == PER_SUNOS)
                pt_succ_return (regs, val);
        else
                pt_succ_return_linux (regs, val, addr);
}

/* Fuck me gently with a chainsaw... */
static inline void read_sunos_user(struct pt_regs *regs, unsigned long offset,
                                   struct task_struct *tsk, long __user *addr)
{
        struct pt_regs *cregs = tsk->thread.kregs;
        struct thread_info *t = task_thread_info(tsk);
        int v;
        
        if(offset >= 1024)
                offset -= 1024; /* whee... */
        if(offset & ((sizeof(unsigned long) - 1))) {
                pt_error_return(regs, EIO);
                return;
        }
        if(offset >= 16 && offset < 784) {
                offset -= 16; offset >>= 2;
                pt_os_succ_return(regs, *(((unsigned long *)(&t->reg_window[0]))+offset), addr);
                return;
        }
        if(offset >= 784 && offset < 832) {
                offset -= 784; offset >>= 2;
                pt_os_succ_return(regs, *(((unsigned long *)(&t->rwbuf_stkptrs[0]))+offset), addr);
                return;
        }
        switch(offset) {
        case 0:
                v = t->ksp;
                break;
        case 4:
                v = t->kpc;
                break;
        case 8:
                v = t->kpsr;
                break;
        case 12:
                v = t->uwinmask;
                break;
        case 832:
                v = t->w_saved;
                break;
        case 896:
                v = cregs->u_regs[UREG_I0];
                break;
        case 900:
                v = cregs->u_regs[UREG_I1];
                break;
        case 904:
                v = cregs->u_regs[UREG_I2];
                break;
        case 908:
                v = cregs->u_regs[UREG_I3];
                break;
        case 912:
                v = cregs->u_regs[UREG_I4];
                break;
        case 916:
                v = cregs->u_regs[UREG_I5];
                break;
        case 920:
                v = cregs->u_regs[UREG_I6];
                break;
        case 924:
                if(tsk->thread.flags & MAGIC_CONSTANT)
                        v = cregs->u_regs[UREG_G1];
                else
                        v = 0;
                break;
        case 940:
                v = cregs->u_regs[UREG_I0];
                break;
        case 944:
                v = cregs->u_regs[UREG_I1];
                break;

        case 948:
                /* Isn't binary compatibility _fun_??? */
                if(cregs->psr & PSR_C)
                        v = cregs->u_regs[UREG_I0] << 24;
                else
                        v = 0;
                break;

                /* Rest of them are completely unsupported. */
        default:
                printk("%s [%d]: Wants to read user offset %ld\n",
                       current->comm, task_pid_nr(current), offset);
                pt_error_return(regs, EIO);
                return;
        }
        if (current->personality == PER_SUNOS)
                pt_succ_return (regs, v);
        else
                pt_succ_return_linux (regs, v, addr);
        return;
}

static inline void write_sunos_user(struct pt_regs *regs, unsigned long offset,
                                    struct task_struct *tsk)
{
        struct pt_regs *cregs = tsk->thread.kregs;
        struct thread_info *t = task_thread_info(tsk);
        unsigned long value = regs->u_regs[UREG_I3];

        if(offset >= 1024)
                offset -= 1024; /* whee... */
        if(offset & ((sizeof(unsigned long) - 1)))
                goto failure;
        if(offset >= 16 && offset < 784) {
                offset -= 16; offset >>= 2;
                *(((unsigned long *)(&t->reg_window[0]))+offset) = value;
                goto success;
        }
        if(offset >= 784 && offset < 832) {
                offset -= 784; offset >>= 2;
                *(((unsigned long *)(&t->rwbuf_stkptrs[0]))+offset) = value;
                goto success;
        }
        switch(offset) {
        case 896:
                cregs->u_regs[UREG_I0] = value;
                break;
        case 900:
                cregs->u_regs[UREG_I1] = value;
                break;
        case 904:
                cregs->u_regs[UREG_I2] = value;
                break;
        case 908:
                cregs->u_regs[UREG_I3] = value;
                break;
        case 912:
                cregs->u_regs[UREG_I4] = value;
                break;
        case 916:
                cregs->u_regs[UREG_I5] = value;
                break;
        case 920:
                cregs->u_regs[UREG_I6] = value;
                break;
        case 924:
                cregs->u_regs[UREG_I7] = value;
                break;
        case 940:
                cregs->u_regs[UREG_I0] = value;
                break;
        case 944:
                cregs->u_regs[UREG_I1] = value;
                break;

                /* Rest of them are completely unsupported or "no-touch". */
        default:
                printk("%s [%d]: Wants to write user offset %ld\n",
                       current->comm, task_pid_nr(current), offset);
                goto failure;
        }
success:
        pt_succ_return(regs, 0);
        return;
failure:
        pt_error_return(regs, EIO);
        return;
}

/* #define ALLOW_INIT_TRACING */
/* #define DEBUG_PTRACE */

#ifdef DEBUG_PTRACE
char *pt_rq [] = {
        /* 0  */ "TRACEME", "PEEKTEXT", "PEEKDATA", "PEEKUSR",
        /* 4  */ "POKETEXT", "POKEDATA", "POKEUSR", "CONT",
        /* 8  */ "KILL", "SINGLESTEP", "SUNATTACH", "SUNDETACH",
        /* 12 */ "GETREGS", "SETREGS", "GETFPREGS", "SETFPREGS",
        /* 16 */ "READDATA", "WRITEDATA", "READTEXT", "WRITETEXT",
        /* 20 */ "GETFPAREGS", "SETFPAREGS", "unknown", "unknown",
        /* 24 */ "SYSCALL", ""
};
#endif

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
        /* nothing to do */
}

asmlinkage void do_ptrace(struct pt_regs *regs)
{
        unsigned long request = regs->u_regs[UREG_I0];
        unsigned long pid = regs->u_regs[UREG_I1];
        unsigned long addr = regs->u_regs[UREG_I2];
        unsigned long data = regs->u_regs[UREG_I3];
        unsigned long addr2 = regs->u_regs[UREG_I4];
        struct task_struct *child;
        int ret;

        lock_kernel();
#ifdef DEBUG_PTRACE
        {
                char *s;

                if ((request >= 0) && (request <= 24))
                        s = pt_rq [request];
                else
                        s = "unknown";

                if (request == PTRACE_POKEDATA && data == 0x91d02001){
                        printk ("do_ptrace: breakpoint pid=%d, addr=%08lx addr2=%08lx\n",
                                pid, addr, addr2);
                } else 
                        printk("do_ptrace: rq=%s(%d) pid=%d addr=%08lx data=%08lx addr2=%08lx\n",
                               s, (int) request, (int) pid, addr, data, addr2);
        }
#endif

        if (request == PTRACE_TRACEME) {
                ret = ptrace_traceme();
                if (ret < 0)
                        pt_error_return(regs, -ret);
                else
                        pt_succ_return(regs, 0);
                goto out;
        }

        child = ptrace_get_task_struct(pid);
        if (IS_ERR(child)) {
                ret = PTR_ERR(child);
                pt_error_return(regs, -ret);
                goto out;
        }

        if ((current->personality == PER_SUNOS && request == PTRACE_SUNATTACH)
            || (current->personality != PER_SUNOS && request == PTRACE_ATTACH)) {
                if (ptrace_attach(child)) {
                        pt_error_return(regs, EPERM);
                        goto out_tsk;
                }
                pt_succ_return(regs, 0);
                goto out_tsk;
        }

        ret = ptrace_check_attach(child, request == PTRACE_KILL);
        if (ret < 0) {
                pt_error_return(regs, -ret);
                goto out_tsk;
        }

        switch(request) {
        case PTRACE_PEEKTEXT: /* read word at location addr. */ 
        case PTRACE_PEEKDATA: {
                unsigned long tmp;

                if (access_process_vm(child, addr,
                                      &tmp, sizeof(tmp), 0) == sizeof(tmp))
                        pt_os_succ_return(regs, tmp, (long __user *)data);
                else
                        pt_error_return(regs, EIO);
                goto out_tsk;
        }

        case PTRACE_PEEKUSR:
                read_sunos_user(regs, addr, child, (long __user *) data);
                goto out_tsk;

        case PTRACE_POKEUSR:
                write_sunos_user(regs, addr, child);
                goto out_tsk;

        case PTRACE_POKETEXT: /* write the word at location addr. */
        case PTRACE_POKEDATA: {
                if (access_process_vm(child, addr,
                                      &data, sizeof(data), 1) == sizeof(data))
                        pt_succ_return(regs, 0);
                else
                        pt_error_return(regs, EIO);
                goto out_tsk;
        }

        case PTRACE_GETREGS: {
                struct pt_regs __user *pregs = (struct pt_regs __user *) addr;
                struct pt_regs *cregs = child->thread.kregs;
                int rval;

                if (!access_ok(VERIFY_WRITE, pregs, sizeof(struct pt_regs))) {
                        rval = -EFAULT;
                        pt_error_return(regs, -rval);
                        goto out_tsk;
                }
                __put_user(cregs->psr, (&pregs->psr));
                __put_user(cregs->pc, (&pregs->pc));
                __put_user(cregs->npc, (&pregs->npc));
                __put_user(cregs->y, (&pregs->y));
                for(rval = 1; rval < 16; rval++)
                        __put_user(cregs->u_regs[rval], (&pregs->u_regs[rval - 1]));
                pt_succ_return(regs, 0);
#ifdef DEBUG_PTRACE
                printk ("PC=%x nPC=%x o7=%x\n", cregs->pc, cregs->npc, cregs->u_regs [15]);
#endif
                goto out_tsk;
        }

        case PTRACE_SETREGS: {
                struct pt_regs __user *pregs = (struct pt_regs __user *) addr;
                struct pt_regs *cregs = child->thread.kregs;
                unsigned long psr, pc, npc, y;
                int i;

                /* Must be careful, tracing process can only set certain
                 * bits in the psr.
                 */
                if (!access_ok(VERIFY_READ, pregs, sizeof(struct pt_regs))) {
                        pt_error_return(regs, EFAULT);
                        goto out_tsk;
                }
                __get_user(psr, (&pregs->psr));
                __get_user(pc, (&pregs->pc));
                __get_user(npc, (&pregs->npc));
                __get_user(y, (&pregs->y));
                psr &= PSR_ICC;
                cregs->psr &= ~PSR_ICC;
                cregs->psr |= psr;
                if (!((pc | npc) & 3)) {
                        cregs->pc = pc;
                        cregs->npc =npc;
                }
                cregs->y = y;
                for(i = 1; i < 16; i++)
                        __get_user(cregs->u_regs[i], (&pregs->u_regs[i-1]));
                pt_succ_return(regs, 0);
                goto out_tsk;
        }

        case PTRACE_GETFPREGS: {
                struct fps {
                        unsigned long regs[32];
                        unsigned long fsr;
                        unsigned long flags;
                        unsigned long extra;
                        unsigned long fpqd;
                        struct fq {
                                unsigned long *insnaddr;
                                unsigned long insn;
                        } fpq[16];
                };
                struct fps __user *fps = (struct fps __user *) addr;
                int i;

                if (!access_ok(VERIFY_WRITE, fps, sizeof(struct fps))) {
                        i = -EFAULT;
                        pt_error_return(regs, -i);
                        goto out_tsk;
                }
                for(i = 0; i < 32; i++)
                        __put_user(child->thread.float_regs[i], (&fps->regs[i]));
                __put_user(child->thread.fsr, (&fps->fsr));
                __put_user(child->thread.fpqdepth, (&fps->fpqd));
                __put_user(0, (&fps->flags));
                __put_user(0, (&fps->extra));
                for(i = 0; i < 16; i++) {
                        __put_user(child->thread.fpqueue[i].insn_addr,
                                   (&fps->fpq[i].insnaddr));
                        __put_user(child->thread.fpqueue[i].insn, (&fps->fpq[i].insn));
                }
                pt_succ_return(regs, 0);
                goto out_tsk;
        }

        case PTRACE_SETFPREGS: {
                struct fps {
                        unsigned long regs[32];
                        unsigned long fsr;
                        unsigned long flags;
                        unsigned long extra;
                        unsigned long fpqd;
                        struct fq {
                                unsigned long *insnaddr;
                                unsigned long insn;
                        } fpq[16];
                };
                struct fps __user *fps = (struct fps __user *) addr;
                int i;

                if (!access_ok(VERIFY_READ, fps, sizeof(struct fps))) {
                        i = -EFAULT;
                        pt_error_return(regs, -i);
                        goto out_tsk;
                }
                copy_from_user(&child->thread.float_regs[0], &fps->regs[0], (32 * sizeof(unsigned long)));
                __get_user(child->thread.fsr, (&fps->fsr));
                __get_user(child->thread.fpqdepth, (&fps->fpqd));
                for(i = 0; i < 16; i++) {
                        __get_user(child->thread.fpqueue[i].insn_addr,
                                   (&fps->fpq[i].insnaddr));
                        __get_user(child->thread.fpqueue[i].insn, (&fps->fpq[i].insn));
                }
                pt_succ_return(regs, 0);
                goto out_tsk;
        }

        case PTRACE_READTEXT:
        case PTRACE_READDATA: {
                int res = ptrace_readdata(child, addr,
                                          (void __user *) addr2, data);

                if (res == data) {
                        pt_succ_return(regs, 0);
                        goto out_tsk;
                }
                /* Partial read is an IO failure */
                if (res >= 0)
                        res = -EIO;
                pt_error_return(regs, -res);
                goto out_tsk;
        }

        case PTRACE_WRITETEXT:
        case PTRACE_WRITEDATA: {
                int res = ptrace_writedata(child, (void __user *) addr2,
                                           addr, data);

                if (res == data) {
                        pt_succ_return(regs, 0);
                        goto out_tsk;
                }
                /* Partial write is an IO failure */
                if (res >= 0)
                        res = -EIO;
                pt_error_return(regs, -res);
                goto out_tsk;
        }

        case PTRACE_SYSCALL: /* continue and stop at (return from) syscall */
                addr = 1;

        case PTRACE_CONT: { /* restart after signal. */
                if (!valid_signal(data)) {
                        pt_error_return(regs, EIO);
                        goto out_tsk;
                }

                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;
#ifdef DEBUG_PTRACE
                printk("CONT: %s [%d]: set exit_code = %x %lx %lx\n",
                        child->comm, child->pid, child->exit_code,
                        child->thread.kregs->pc,
                        child->thread.kregs->npc);
#endif
                wake_up_process(child);
                pt_succ_return(regs, 0);
                goto out_tsk;
        }

/*
 * 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: {
                if (child->exit_state == EXIT_ZOMBIE) { /* already dead */
                        pt_succ_return(regs, 0);
                        goto out_tsk;
                }
                wake_up_process(child);
                child->exit_code = SIGKILL;
                pt_succ_return(regs, 0);
                goto out_tsk;
        }

        case PTRACE_SUNDETACH: { /* detach a process that was attached. */
                int err = ptrace_detach(child, data);
                if (err) {
                        pt_error_return(regs, EIO);
                        goto out_tsk;
                }
                pt_succ_return(regs, 0);
                goto out_tsk;
        }

        /* PTRACE_DUMPCORE unsupported... */

        default: {
                int err = ptrace_request(child, request, addr, data);
                if (err)
                        pt_error_return(regs, -err);
                else
                        pt_succ_return(regs, 0);
                goto out_tsk;
        }
        }
out_tsk:
        if (child)
                put_task_struct(child);
out:
        unlock_kernel();
}

asmlinkage void syscall_trace(void)
{
#ifdef DEBUG_PTRACE
        printk("%s [%d]: syscall_trace\n", current->comm, current->pid);
#endif
        if (!test_thread_flag(TIF_SYSCALL_TRACE))
                return;
        if (!(current->ptrace & PT_PTRACED))
                return;
        current->thread.flags ^= MAGIC_CONSTANT;
        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
         */
#ifdef DEBUG_PTRACE
        printk("%s [%d]: syscall_trace exit= %x\n", current->comm,
                current->pid, current->exit_code);
#endif
        if (current->exit_code) {
                send_sig (current->exit_code, current, 1);
                current->exit_code = 0;
        }
}