patch-1.3.96 linux/arch/sparc/kernel/ptrace.c

• Lines: 802
• Date: Thu Apr 25 13:22:05 1996
• Orig file: v1.3.95/linux/arch/sparc/kernel/ptrace.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.95/linux/arch/sparc/kernel/ptrace.c linux/arch/sparc/kernel/ptrace.c
@@ -0,0 +1,801 @@
+/* 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.
+ */
+
+#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 <asm/pgtable.h>
+#include <asm/system.h>
+
+/* change a pid into a task struct. */
+static inline struct task_struct * get_task(int pid)
+{
+	int i;
+
+	for (i = 1; i < NR_TASKS; i++) {
+		if (task[i] != NULL && (task[i]->pid == pid))
+			return task[i];
+	}
+	return NULL;
+}
+
+/*
+ * This routine gets a long from any process space by following the page
+ * tables. NOTE! You should check that the long isn't on a page boundary,
+ * and that it is in the task area before calling this: this routine does
+ * no checking.
+ */
+static unsigned long get_long(struct task_struct * tsk,
+	struct vm_area_struct * vma, unsigned long addr)
+{
+	pgd_t * pgdir;
+	pmd_t * pgmiddle;
+	pte_t * pgtable;
+	unsigned long page, retval;
+
+repeat:
+	pgdir = pgd_offset(vma->vm_mm, addr);
+	if (pgd_none(*pgdir)) {
+		do_no_page(tsk, vma, addr, 0);
+		goto repeat;
+	}
+	if (pgd_bad(*pgdir)) {
+		printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
+		pgd_clear(pgdir);
+		return 0;
+	}
+	pgmiddle = pmd_offset(pgdir, addr);
+	if (pmd_none(*pgmiddle)) {
+		do_no_page(tsk, vma, addr, 0);
+		goto repeat;
+	}
+	if (pmd_bad(*pgmiddle)) {
+		printk("ptrace: bad page middle %08lx\n", pmd_val(*pgmiddle));
+		pmd_clear(pgmiddle);
+		return 0;
+	}
+	pgtable = pte_offset(pgmiddle, addr);
+	if (!pte_present(*pgtable)) {
+		do_no_page(tsk, vma, addr, 0);
+		goto repeat;
+	}
+	page = pte_page(*pgtable);
+/* this is a hack for non-kernel-mapped video buffers and similar */
+	if (page >= high_memory)
+		return 0;
+	page += addr & ~PAGE_MASK;
+	retval = *(unsigned long *) page;
+	flush_page_to_ram(page);
+	return retval;
+}
+
+/*
+ * This routine puts a long into any process space by following the page
+ * tables. NOTE! You should check that the long isn't on a page boundary,
+ * and that it is in the task area before calling this: this routine does
+ * no checking.
+ *
+ * Now keeps R/W state of page so that a text page stays readonly
+ * even if a debugger scribbles breakpoints into it.  -M.U-
+ */
+static void put_long(struct task_struct * tsk, struct vm_area_struct * vma,
+	unsigned long addr, unsigned long data)
+{
+	pgd_t *pgdir;
+	pmd_t *pgmiddle;
+	pte_t *pgtable;
+	unsigned long page;
+
+repeat:
+	pgdir = pgd_offset(vma->vm_mm, addr);
+	if (!pgd_present(*pgdir)) {
+		do_no_page(tsk, vma, addr, 1);
+		goto repeat;
+	}
+	if (pgd_bad(*pgdir)) {
+		printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
+		pgd_clear(pgdir);
+		return;
+	}
+	pgmiddle = pmd_offset(pgdir, addr);
+	if (pmd_none(*pgmiddle)) {
+		do_no_page(tsk, vma, addr, 1);
+		goto repeat;
+	}
+	if (pmd_bad(*pgmiddle)) {
+		printk("ptrace: bad page middle %08lx\n", pmd_val(*pgmiddle));
+		pmd_clear(pgmiddle);
+		return;
+	}
+	pgtable = pte_offset(pgmiddle, addr);
+	if (!pte_present(*pgtable)) {
+		do_no_page(tsk, vma, addr, 1);
+		goto repeat;
+	}
+	page = pte_page(*pgtable);
+	if (!pte_write(*pgtable)) {
+		do_wp_page(tsk, vma, addr, 1);
+		goto repeat;
+	}
+/* this is a hack for non-kernel-mapped video buffers and similar */
+	flush_cache_page(vma, page);
+	if (page < high_memory) {
+		*(unsigned long *) (page + (addr & ~PAGE_MASK)) = data;
+		flush_page_to_ram(page);
+	}
+/* we're bypassing pagetables, so we have to set the dirty bit ourselves */
+/* this should also re-instate whatever read-only mode there was before */
+	set_pte(pgtable, pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
+	flush_tlb_page(vma, page);
+}
+
+static struct vm_area_struct * find_extend_vma(struct task_struct * tsk,
+					       unsigned long addr)
+{
+	struct vm_area_struct * vma;
+
+	addr &= PAGE_MASK;
+	vma = find_vma(tsk,addr);
+	if (!vma)
+		return NULL;
+	if (vma->vm_start <= addr)
+		return vma;
+	if (!(vma->vm_flags & VM_GROWSDOWN))
+		return NULL;
+	if (vma->vm_end - addr > tsk->rlim[RLIMIT_STACK].rlim_cur)
+		return NULL;
+	vma->vm_offset -= vma->vm_start - addr;
+	vma->vm_start = addr;
+	return vma;
+}
+
+/*
+ * This routine checks the page boundaries, and that the offset is
+ * within the task area. It then calls get_long() to read a long.
+ */
+static int read_long(struct task_struct * tsk, unsigned long addr,
+		     unsigned long * result)
+{
+	struct vm_area_struct * vma = find_extend_vma(tsk, addr);
+
+	if (!vma)
+		return -EIO;
+	*result = get_long(tsk, vma, addr);
+	return 0;
+}
+
+static int read_byte(struct task_struct *tsk, unsigned long addr,
+		     unsigned char *result)
+{
+	struct vm_area_struct *vma = find_extend_vma(tsk, addr&~3);
+	unsigned long tmp;
+
+	if(!vma)
+		return -EIO;
+	tmp = get_long(tsk, vma, (addr & ~3));
+	switch(addr & 3) {
+	case 0:
+		*result = (tmp & 0xff000000)>>24;
+		break;
+	case 1:
+		*result = (tmp & 0x00ff0000)>>16;
+		break;
+	case 2:
+		*result = (tmp & 0x0000ff00)>>8;
+		break;
+	case 3:
+		*result = (tmp & 0x000000ff);
+		break;
+	}
+	return 0;
+}
+
+/*
+ * This routine checks the page boundaries, and that the offset is
+ * within the task area. It then calls put_long() to write a long.
+ */
+static int write_long(struct task_struct * tsk, unsigned long addr,
+		      unsigned long data)
+{
+	struct vm_area_struct * vma = find_extend_vma(tsk, addr);
+
+	if (!vma)
+		return -EIO;
+	put_long(tsk, vma, addr, data);
+	return 0;
+}
+
+static int write_byte(struct task_struct * tsk, unsigned long addr,
+		      unsigned char data)
+{
+	struct vm_area_struct * vma = find_extend_vma(tsk, (addr & ~3));
+	unsigned long tmp;
+
+	if (!vma)
+		return -EIO;
+	tmp = get_long(tsk, vma, (addr & ~3));
+	switch(addr & 3) {
+	case 0:
+		tmp &= 0x00ffffff;
+		tmp |= (data << 24);
+		break;
+	case 1:
+		tmp &= 0xff00ffff;
+		tmp |= ((data << 16) & 0x00ff0000);
+		break;
+	case 2:
+		tmp &= 0xffff00ff;
+		tmp |= ((data << 8) & 0x0000ff00);
+		break;
+	case 3:
+		tmp &= 0xffffff00;
+		tmp |= (data & 0x000000ff);
+		break;
+	}
+	put_long(tsk, vma, (addr & ~3), tmp);
+	return 0;
+}
+
+/* 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;
+}
+
+/* Fuck me gently with a chainsaw... */
+static inline void read_sunos_user(struct pt_regs *regs, unsigned long offset,
+				   struct task_struct *tsk)
+{
+	struct pt_regs *cregs = tsk->tss.kregs;
+	struct thread_struct *t = &tsk->tss;
+
+	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_succ_return(regs, *(((unsigned long *)(&t->reg_window[0]))+offset));	
+		return;
+	}
+	if(offset >= 784 && offset < 832) {
+		offset -= 784; offset >>= 2;
+		pt_succ_return(regs, *(((unsigned long *)(&t->rwbuf_stkptrs[0]))+offset));
+		return;
+	}
+	switch(offset) {
+	case 0:
+		regs->u_regs[UREG_I0] = t->ksp;
+		break;
+	case 4:
+		regs->u_regs[UREG_I0] = t->kpc;
+		break;
+	case 8:
+		regs->u_regs[UREG_I0] = t->kpsr;
+		break;
+	case 12:
+		regs->u_regs[UREG_I0] = t->uwinmask;
+		break;
+	case 832:
+		regs->u_regs[UREG_I0] = t->w_saved;
+		break;
+	case 896:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I0];
+		break;
+	case 900:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I1];
+		break;
+	case 904:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I2];
+		break;
+	case 908:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I3];
+		break;
+	case 912:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I4];
+		break;
+	case 916:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I5];
+		break;
+	case 920:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I6];
+		break;
+	case 924:
+		if(tsk->tss.flags & 0x80000000)
+			regs->u_regs[UREG_I0] = cregs->u_regs[UREG_G1];
+		else
+			regs->u_regs[UREG_I0] = 0;
+		break;
+	case 940:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I0];
+		break;
+	case 944:
+		regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I1];
+		break;
+
+	case 948:
+		/* Isn't binary compatability _fun_??? */
+		if(cregs->psr & PSR_C)
+			regs->u_regs[UREG_I0] = cregs->u_regs[UREG_I0] << 24;
+		else
+			regs->u_regs[UREG_I0] = 0;
+		break;
+
+		/* Rest of them are completely unsupported. */
+	default:
+		printk("%s [%d]: Wants to read user offset %d\n",
+		       current->comm, current->pid, offset);
+		pt_error_return(regs, EIO);
+		return;
+	}
+	regs->psr &= ~PSR_C;
+	regs->pc = regs->npc;
+	regs->npc += 4;
+	return;
+}
+
+static inline void write_sunos_user(struct pt_regs *regs, unsigned long offset,
+				    struct task_struct *tsk)
+{
+	struct pt_regs *cregs = tsk->tss.kregs;
+	struct thread_struct *t = &tsk->tss;
+	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 %d\n",
+		       current->comm, current->pid, offset);
+		goto failure;
+	}
+success:
+	pt_succ_return(regs, 0);
+	return;
+failure:
+	pt_error_return(regs, EIO);
+	return;
+}
+
+/* #define ALLOW_INIT_TRACING */
+/* #define DEBUG_PTRACE */
+
+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;
+
+#ifdef DEBUG_PTRACE
+	printk("do_ptrace: rq=%d pid=%d addr=%08lx data=%08lx addr2=%08lx\n",
+	       (int) request, (int) pid, addr, data, addr2);
+#endif
+	if(request == PTRACE_TRACEME) {
+		/* are we already being traced? */
+		if (current->flags & PF_PTRACED) {
+			pt_error_return(regs, EPERM);
+			return;
+		}
+		/* set the ptrace bit in the process flags. */
+		current->flags |= PF_PTRACED;
+		pt_succ_return(regs, 0);
+		return;
+	}
+#ifndef ALLOW_INIT_TRACING
+	if(pid == 1) {
+		/* Can't dork with init. */
+		pt_error_return(regs, EPERM);
+		return;
+	}
+#endif
+	if(!(child = get_task(pid))) {
+		pt_error_return(regs, ESRCH);
+		return;
+	}
+
+	if(request == PTRACE_SUNATTACH) {
+		if(child == current) {
+			/* Try this under SunOS/Solaris, bwa haha
+			 * You'll never be able to kill the process. ;-)
+			 */
+			pt_error_return(regs, EPERM);
+			return;
+		}
+		if((!child->dumpable ||
+		    (current->uid != child->euid) ||
+		    (current->uid != child->uid) ||
+		    (current->gid != child->egid) ||
+		    (current->gid != child->gid)) && !suser()) {
+			pt_error_return(regs, EPERM);
+			return;
+		}
+		/* the same process cannot be attached many times */
+		if (child->flags & PF_PTRACED) {
+			pt_error_return(regs, EPERM);
+			return;
+		}
+		child->flags |= PF_PTRACED;
+		if(child->p_pptr != current) {
+			REMOVE_LINKS(child);
+			child->p_pptr = current;
+			SET_LINKS(child);
+		}
+		send_sig(SIGSTOP, child, 1);
+		pt_succ_return(regs, 0);
+		return;
+	}
+	if(!(child->flags & PF_PTRACED)) {
+		pt_error_return(regs, ESRCH);
+		return;
+	}
+	if(child->state != TASK_STOPPED) {
+		if(request != PTRACE_KILL) {
+			pt_error_return(regs, ESRCH);
+			return;
+		}
+	}
+	if(child->p_pptr != current) {
+		pt_error_return(regs, ESRCH);
+		return;
+	}
+	switch(request) {
+	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
+	case PTRACE_PEEKDATA: {
+		unsigned long tmp;
+		int res;
+
+		/* Non-word alignment _not_ allowed on Sparc. */
+		if(addr & (sizeof(unsigned long) - 1)) {
+			pt_error_return(regs, EINVAL);
+			return;
+		}
+		res = read_long(child, addr, &tmp);
+		if (res < 0) {
+			pt_error_return(regs, -res);
+			return;
+		}
+		pt_succ_return(regs, tmp);
+		return;
+	}
+
+	case PTRACE_PEEKUSR:
+		read_sunos_user(regs, addr, child);
+		return;
+
+	case PTRACE_POKEUSR:
+		write_sunos_user(regs, addr, child);
+		return;
+
+	case PTRACE_POKETEXT: /* write the word at location addr. */
+	case PTRACE_POKEDATA: {
+		struct vm_area_struct *vma;
+		int res;
+
+		/* Non-word alignment _not_ allowed on Sparc. */
+		if(addr & (sizeof(unsigned long) - 1)) {
+			pt_error_return(regs, EINVAL);
+			return;
+		}
+		vma = find_extend_vma(child, addr);
+		if(vma && request == PTRACE_POKEDATA && (vma->vm_flags & VM_EXEC)) {
+			pt_error_return(regs, EIO);
+			return;
+		}
+		res = write_long(child, addr, data);
+		if(res < 0)
+			pt_error_return(regs, -res);
+		else
+			pt_succ_return(regs, res);
+		return;
+	}
+
+	case PTRACE_GETREGS: {
+		struct pt_regs *pregs = (struct pt_regs *) addr;
+		struct pt_regs *cregs = child->tss.kregs;
+		int rval;
+
+		rval = verify_area(VERIFY_WRITE, pregs, sizeof(struct pt_regs) - 4);
+		if(rval) {
+			pt_error_return(regs, rval);
+			return;
+		}
+		pregs->psr = cregs->psr;
+		pregs->pc = cregs->pc;
+		pregs->npc = cregs->npc;
+		pregs->y = cregs->y;
+		for(rval = 1; rval < 16; rval++)
+			pregs->u_regs[rval - 1] = cregs->u_regs[rval];
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	case PTRACE_SETREGS: {
+		struct pt_regs *pregs = (struct pt_regs *) addr;
+		struct pt_regs *cregs = child->tss.kregs;
+		unsigned long psr;
+		int rval, i;
+
+		rval = verify_area(VERIFY_READ, pregs, sizeof(struct pt_regs) - 4);
+		if(rval) {
+			pt_error_return(regs, rval);
+			return;
+		}
+		/* Must be careful, tracing process can only set certain
+		 * bits in the psr.
+		 */
+		psr = (pregs->psr) & PSR_ICC;
+		cregs->psr &= ~PSR_ICC;
+		cregs->psr |= psr;
+		if(!((pregs->pc | pregs->npc) & 3)) {
+			cregs->pc = pregs->pc;
+			cregs->npc = pregs->npc;
+		}
+		cregs->y = pregs->y;
+		for(i = 1; i < 16; i++)
+			cregs->u_regs[i] = pregs->u_regs[i-1];
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	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];
+		} *fps = (struct fps *) addr;
+		int rval, i;
+
+		rval = verify_area(VERIFY_WRITE, fps, sizeof(struct fps));
+		if(rval) { pt_error_return(regs, rval); return; }
+		for(i = 0; i < 32; i++)
+			fps->regs[i] = child->tss.float_regs[i];
+		fps->fsr = child->tss.fsr;
+		fps->fpqd = child->tss.fpqdepth;
+		fps->flags = fps->extra = 0;
+		for(i = 0; i < 16; i++) {
+			fps->fpq[i].insnaddr = child->tss.fpqueue[i].insn_addr;
+			fps->fpq[i].insn = child->tss.fpqueue[i].insn;
+		}
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	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];
+		} *fps = (struct fps *) addr;
+		int rval, i;
+
+		rval = verify_area(VERIFY_READ, fps, sizeof(struct fps));
+		if(rval) { pt_error_return(regs, rval); return; }
+		for(i = 0; i < 32; i++)
+			child->tss.float_regs[i] = fps->regs[i];
+		child->tss.fsr = fps->fsr;
+		child->tss.fpqdepth = fps->fpqd;
+		for(i = 0; i < 16; i++) {
+			child->tss.fpqueue[i].insn_addr = fps->fpq[i].insnaddr;
+			child->tss.fpqueue[i].insn = fps->fpq[i].insn;
+		}
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	case PTRACE_READTEXT:
+	case PTRACE_READDATA: {
+		unsigned char *dest = (unsigned char *) addr2;
+		unsigned long src = addr;
+		unsigned char tmp;
+		int res, len = data;
+
+		res = verify_area(VERIFY_WRITE, (void *) dest, len);
+		if(res) {
+			pt_error_return(regs, -res);
+			return;
+		}
+		while(len) {
+			res = read_byte(child, src, &tmp);
+			if(res < 0) {
+				pt_error_return(regs, -res);
+				return;
+			}
+			*dest = tmp;
+			src++; dest++; len--;
+		}
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	case PTRACE_WRITETEXT:
+	case PTRACE_WRITEDATA: {
+		unsigned char *src = (unsigned char *) addr2;
+		unsigned long dest = addr;
+		int res, len = data;
+
+		res = verify_area(VERIFY_READ, (void *) src, len);
+		if(res) {
+			pt_error_return(regs, -res);
+			return;
+		}
+		while(len) {
+			res = write_byte(child, dest, *src);
+			if(res < 0) {
+				pt_error_return(regs, -res);
+				return;
+			}
+			src++; dest++; len--;
+		}
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	case PTRACE_SYSCALL: /* continue and stop at (return from) syscall */
+		data = 0;
+		addr = 1;
+
+	case PTRACE_CONT: { /* restart after signal. */
+		if ((unsigned long) data > NSIG) {
+			pt_error_return(regs, EIO);
+			return;
+		}
+		if (request == PTRACE_SYSCALL)
+			child->flags |= PF_TRACESYS;
+		else
+			child->flags &= ~PF_TRACESYS;
+		child->exit_code = data;
+		if((addr != 1) & !(addr & 3)) {
+			child->tss.kregs->pc = addr;
+			child->tss.kregs->npc = addr + 4;
+		}
+		wake_up_process(child);
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+/*
+ * 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->state == TASK_ZOMBIE) {	/* already dead */
+			pt_succ_return(regs, 0);
+			return;
+		}
+		wake_up_process(child);
+		child->exit_code = SIGKILL;
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	case PTRACE_SUNDETACH: { /* detach a process that was attached. */
+		if ((unsigned long) data > NSIG) {
+			pt_error_return(regs, EIO);
+			return;
+		}
+		child->flags &= ~(PF_PTRACED|PF_TRACESYS);
+		wake_up_process(child);
+		child->exit_code = data;
+		REMOVE_LINKS(child);
+		child->p_pptr = child->p_opptr;
+		SET_LINKS(child);
+		pt_succ_return(regs, 0);
+		return;
+	}
+
+	/* PTRACE_DUMPCORE unsupported... */
+
+	default:
+		pt_error_return(regs, EIO);
+		return;
+	}
+}
+
+asmlinkage void syscall_trace(void)
+{
+#ifdef DEBUG_PTRACE
+	printk("%s [%d]: syscall_trace\n", current->comm, current->pid);
+#endif
+	if ((current->flags & (PF_PTRACED|PF_TRACESYS))
+			!= (PF_PTRACED|PF_TRACESYS))
+		return;
+	current->exit_code = SIGTRAP;
+	current->state = TASK_STOPPED;
+	current->tss.flags ^= 0x80000000;
+	notify_parent(current);
+	schedule();
+	/*
+	 * 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)
+		current->signal |= (1 << (current->exit_code - 1));
+	current->exit_code = 0;
+}