ptrace.c

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/* ptrace.c: Sparc process tracing support.
 *
 * Copyright (C) 1996 David S. Miller ([e-mail])
 * Copyright (C) 1997 Jakub Jelinek ([e-mail])
 *
 * Based upon code written by Ross Biro, Linus Torvalds, Bob Manson,
 * and David Mosberger.
 *
 * Added Linux support -miguel (wierd, eh?, the orignal 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 <asm/asi.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/psrcompat.h>
#include <asm/visasm.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->tstate |= (TSTATE_ICARRY | TSTATE_XCARRY);
	regs->tpc = regs->tnpc;
	regs->tnpc += 4;
}

static inline void pt_succ_return(struct pt_regs *regs, unsigned long value)
{
	regs->u_regs[UREG_I0] = value;
	regs->tstate &= ~(TSTATE_ICARRY | TSTATE_XCARRY);
	regs->tpc = regs->tnpc;
	regs->tnpc += 4;
}

static inline void
pt_succ_return_linux(struct pt_regs *regs, unsigned long value, long *addr)
{
	if (current->thread.flags & SPARC_FLAG_32BIT) {
		if(put_user(value, (unsigned int *)addr))
			return pt_error_return(regs, EFAULT);
	} else {
		if(put_user(value, addr))
			return pt_error_return(regs, EFAULT);
	}
	regs->u_regs[UREG_I0] = 0;
	regs->tstate &= ~(TSTATE_ICARRY | TSTATE_XCARRY);
	regs->tpc = regs->tnpc;
	regs->tnpc += 4;
}

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

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

#ifdef DEBUG_PTRACE
char *pt_rq [] = {
"TRACEME",
"PEEKTEXT",
"PEEKDATA",
"PEEKUSR",
"POKETEXT",
"POKEDATA",
"POKEUSR",
"CONT",
"KILL",
"SINGLESTEP",
"SUNATTACH",
"SUNDETACH",
"GETREGS",
"SETREGS",
"GETFPREGS",
"SETFPREGS",
"READDATA",
"WRITEDATA",
"READTEXT",
"WRITETEXT",
"GETFPAREGS",
"SETFPAREGS",
""
};
#endif

asmlinkage void do_ptrace(struct pt_regs *regs)
{
	int request = regs->u_regs[UREG_I0];
	pid_t 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;

	if (current->thread.flags & SPARC_FLAG_32BIT) {
		addr &= 0xffffffffUL;
		data &= 0xffffffffUL;
		addr2 &= 0xffffffffUL;
	}
	lock_kernel();
#ifdef DEBUG_PTRACE
	{
		char *s;

		if ((request > 0) && (request < 21))
			s = pt_rq [request];
		else
			s = "unknown";

		if (request == PTRACE_POKEDATA && data == 0x91d02001){
			printk ("do_ptrace: breakpoint pid=%d, addr=%016lx addr2=%016lx\n",
				pid, addr, addr2);
		} else 
			printk("do_ptrace: rq=%s(%d) pid=%d addr=%016lx data=%016lx addr2=%016lx\n",
			       s, request, pid, addr, data, addr2);
	}
#endif
	if(request == PTRACE_TRACEME) {
		/* are we already being traced? */
		if (current->ptrace & PT_PTRACED) {
			pt_error_return(regs, EPERM);
			goto out;
		}
		/* set the ptrace bit in the process flags. */
		current->ptrace |= PT_PTRACED;
		pt_succ_return(regs, 0);
		goto out;
	}
#ifndef ALLOW_INIT_TRACING
	if(pid == 1) {
		/* Can't dork with init. */
		pt_error_return(regs, EPERM);
		goto out;
	}
#endif
	read_lock(&tasklist_lock);
	child = find_task_by_pid(pid);
	read_unlock(&tasklist_lock);

	if(!child) {
		pt_error_return(regs, ESRCH);
		goto out;
	}

	if ((current->personality == PER_SUNOS && request == PTRACE_SUNATTACH)
	    || (current->personality != PER_SUNOS && request == PTRACE_ATTACH)) {
		unsigned long flags;

		if(child == current) {
			/* Try this under SunOS/Solaris, bwa haha
			 * You'll never be able to kill the process. ;-)
			 */
			pt_error_return(regs, EPERM);
			goto out;
		}
		if((!child->dumpable ||
		    (current->uid != child->euid) ||
		    (current->uid != child->uid) ||
		    (current->uid != child->suid) ||
		    (current->gid != child->egid) ||
		    (current->gid != child->sgid) ||
		    (!cap_issubset(child->cap_permitted, current->cap_permitted)) ||
		    (current->gid != child->gid)) && !capable(CAP_SYS_PTRACE)) {
			pt_error_return(regs, EPERM);
			goto out;
		}
		/* the same process cannot be attached many times */
		if (child->ptrace & PT_PTRACED) {
			pt_error_return(regs, EPERM);
			goto out;
		}
		child->ptrace |= PT_PTRACED;
		write_lock_irqsave(&tasklist_lock, flags);
		if(child->p_pptr != current) {
			REMOVE_LINKS(child);
			child->p_pptr = current;
			SET_LINKS(child);
		}
		write_unlock_irqrestore(&tasklist_lock, flags);
		send_sig(SIGSTOP, child, 1);
		pt_succ_return(regs, 0);
		goto out;
	}
	if (!(child->ptrace & PT_PTRACED)) {
		pt_error_return(regs, ESRCH);
		goto out;
	}
	if(child->state != TASK_STOPPED) {
		if(request != PTRACE_KILL) {
			pt_error_return(regs, ESRCH);
			goto out;
		}
	}
	if(child->p_pptr != current) {
		pt_error_return(regs, ESRCH);
		goto out;
	}

	if(!(child->thread.flags & SPARC_FLAG_32BIT)	&&
	   ((request == PTRACE_READDATA64)		||
	    (request == PTRACE_WRITEDATA64)		||
	    (request == PTRACE_READTEXT64)		||
	    (request == PTRACE_WRITETEXT64)		||
	    (request == PTRACE_PEEKTEXT64)		||
	    (request == PTRACE_POKETEXT64)		||
	    (request == PTRACE_PEEKDATA64)		||
	    (request == PTRACE_POKEDATA64))) {
		addr = regs->u_regs[UREG_G2];
		addr2 = regs->u_regs[UREG_G3];
		request -= 30; /* wheee... */
	}

	switch(request) {
	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
	case PTRACE_PEEKDATA: {
		unsigned long tmp64;
		unsigned int tmp32;
		int res, copied;

		res = -EIO;
		if (current->thread.flags & SPARC_FLAG_32BIT) {
			copied = access_process_vm(child, addr,
						   &tmp32, sizeof(tmp32), 0);
			tmp64 = (unsigned long) tmp32;
			if (copied == sizeof(tmp32))
				res = 0;
		} else {
			copied = access_process_vm(child, addr,
						   &tmp64, sizeof(tmp64), 0);
			if (copied == sizeof(tmp64))
				res = 0;
		}
		if (res < 0)
			pt_error_return(regs, -res);
		else
			pt_os_succ_return(regs, tmp64, (long *) data);
		goto flush_and_out;
	}

	case PTRACE_POKETEXT: /* write the word at location addr. */
	case PTRACE_POKEDATA: {
		unsigned long tmp64;
		unsigned int tmp32;
		int copied, res = -EIO;

		if (current->thread.flags & SPARC_FLAG_32BIT) {
			tmp32 = data;
			copied = access_process_vm(child, addr,
						   &tmp32, sizeof(tmp32), 1);
			if (copied == sizeof(tmp32))
				res = 0;
		} else {
			tmp64 = data;
			copied = access_process_vm(child, addr,
						   &tmp64, sizeof(tmp64), 1);
			if (copied == sizeof(tmp64))
				res = 0;
		}
		if(res < 0)
			pt_error_return(regs, -res);
		else
			pt_succ_return(regs, res);
		goto flush_and_out;
	}

	case PTRACE_GETREGS: {
		struct pt_regs32 *pregs = (struct pt_regs32 *) addr;
		struct pt_regs *cregs = child->thread.kregs;
		int rval;

		if (__put_user(tstate_to_psr(cregs->tstate), (&pregs->psr)) ||
		    __put_user(cregs->tpc, (&pregs->pc)) ||
		    __put_user(cregs->tnpc, (&pregs->npc)) ||
		    __put_user(cregs->y, (&pregs->y))) {
			pt_error_return(regs, EFAULT);
			goto out;
		}
		for(rval = 1; rval < 16; rval++)
			if (__put_user(cregs->u_regs[rval], (&pregs->u_regs[rval - 1]))) {
				pt_error_return(regs, EFAULT);
				goto out;
			}
		pt_succ_return(regs, 0);
#ifdef DEBUG_PTRACE
		printk ("PC=%lx nPC=%lx o7=%lx\n", cregs->tpc, cregs->tnpc, cregs->u_regs [15]);
#endif
		goto out;
	}

	case PTRACE_GETREGS64: {
		struct pt_regs *pregs = (struct pt_regs *) addr;
		struct pt_regs *cregs = child->thread.kregs;
		int rval;

		if (__put_user(cregs->tstate, (&pregs->tstate)) ||
		    __put_user(cregs->tpc, (&pregs->tpc)) ||
		    __put_user(cregs->tnpc, (&pregs->tnpc)) ||
		    __put_user(cregs->y, (&pregs->y))) {
			pt_error_return(regs, EFAULT);
			goto out;
		}
		for(rval = 1; rval < 16; rval++)
			if (__put_user(cregs->u_regs[rval], (&pregs->u_regs[rval - 1]))) {
				pt_error_return(regs, EFAULT);