arch/x86/ia32/ptrace32.c - kernel/msm-4.9 - Gitiles

 /*
  * 32bit ptrace for x86-64.
  *
  * Copyright 2001,2002 Andi Kleen, SuSE Labs.
  * Some parts copied from arch/i386/kernel/ptrace.c. See that file for earlier
  * copyright.
  *
  * This allows to access 64bit processes too; but there is no way to see the extended
  * register contents.
  */

 #include <linux/kernel.h>
 #include <linux/stddef.h>
 #include <linux/sched.h>
 #include <linux/syscalls.h>
 #include <linux/unistd.h>
 #include <linux/mm.h>
 #include <linux/err.h>
 #include <linux/ptrace.h>
 #include <asm/ptrace.h>
 #include <asm/compat.h>
 #include <asm/uaccess.h>
 #include <asm/user32.h>
 #include <asm/user.h>
 #include <asm/errno.h>
 #include <asm/debugreg.h>
 #include <asm/i387.h>
 #include <asm/fpu32.h>
 #include <asm/ia32.h>

 /*
  * Determines which flags the user has access to [1 = access, 0 = no access].
  * Prohibits changing ID(21), VIP(20), VIF(19), VM(17), IOPL(12-13), IF(9).
  * Also masks reserved bits (31-22, 15, 5, 3, 1).
  */
 #define FLAG_MASK 0x54dd5UL

 #define R32(l,q) \
 	case offsetof(struct user32, regs.l): stack[offsetof(struct pt_regs, q)/8] = val; break

 static int putreg32(struct task_struct *child, unsigned regno, u32 val)
 {
 	int i;
 	__u64 *stack = (__u64 *)task_pt_regs(child);

 	switch (regno) {
 	case offsetof(struct user32, regs.fs):
 		if (val && (val & 3) != 3) return -EIO;
 		child->thread.fsindex = val & 0xffff;
 		break;
 	case offsetof(struct user32, regs.gs):
 		if (val && (val & 3) != 3) return -EIO;
 		child->thread.gsindex = val & 0xffff;
 		break;
 	case offsetof(struct user32, regs.ds):
 		if (val && (val & 3) != 3) return -EIO;
 		child->thread.ds = val & 0xffff;
 		break;
 	case offsetof(struct user32, regs.es):
 		child->thread.es = val & 0xffff;
 		break;
 	case offsetof(struct user32, regs.ss):
 		if ((val & 3) != 3) return -EIO;
         	stack[offsetof(struct pt_regs, ss)/8] = val & 0xffff;
 		break;
 	case offsetof(struct user32, regs.cs):
 		if ((val & 3) != 3) return -EIO;
 		stack[offsetof(struct pt_regs, cs)/8] = val & 0xffff;
 		break;

 	R32(ebx, rbx);
 	R32(ecx, rcx);
 	R32(edx, rdx);
 	R32(edi, rdi);
 	R32(esi, rsi);
 	R32(ebp, rbp);
 	R32(eax, rax);
 	R32(orig_eax, orig_rax);
 	R32(eip, rip);
 	R32(esp, rsp);

 	case offsetof(struct user32, regs.eflags): {
 		__u64 *flags = &stack[offsetof(struct pt_regs, eflags)/8];
 		val &= FLAG_MASK;
 		*flags = val | (*flags & ~FLAG_MASK);
 		break;
 	}

 	case offsetof(struct user32, u_debugreg[4]):
 	case offsetof(struct user32, u_debugreg[5]):
 		return -EIO;

 	case offsetof(struct user32, u_debugreg[0]):
 		child->thread.debugreg0 = val;
 		break;

 	case offsetof(struct user32, u_debugreg[1]):
 		child->thread.debugreg1 = val;
 		break;

 	case offsetof(struct user32, u_debugreg[2]):
 		child->thread.debugreg2 = val;
 		break;

 	case offsetof(struct user32, u_debugreg[3]):
 		child->thread.debugreg3 = val;
 		break;

 	case offsetof(struct user32, u_debugreg[6]):
 		child->thread.debugreg6 = val;
 		break;

 	case offsetof(struct user32, u_debugreg[7]):
 		val &= ~DR_CONTROL_RESERVED;
 		/* See arch/i386/kernel/ptrace.c for an explanation of
 		 * this awkward check.*/
 		for(i=0; i<4; i++)
 			if ((0x5454 >> ((val >> (16 + 4*i)) & 0xf)) & 1)
 			       return -EIO;
 		child->thread.debugreg7 = val;
 		if (val)
 			set_tsk_thread_flag(child, TIF_DEBUG);
 		else
 			clear_tsk_thread_flag(child, TIF_DEBUG);
 		break;

 	default:
 		if (regno > sizeof(struct user32) || (regno & 3))
 			return -EIO;

 		/* Other dummy fields in the virtual user structure are ignored */
 		break;
 	}
 	return 0;
 }

 #undef R32

 #define R32(l,q) \
 	case offsetof(struct user32, regs.l): *val = stack[offsetof(struct pt_regs, q)/8]; break

 static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
 {
 	__u64 *stack = (__u64 *)task_pt_regs(child);

 	switch (regno) {
 	case offsetof(struct user32, regs.fs):
 	        *val = child->thread.fsindex;
 		break;
 	case offsetof(struct user32, regs.gs):
 		*val = child->thread.gsindex;
 		break;
 	case offsetof(struct user32, regs.ds):
 		*val = child->thread.ds;
 		break;
 	case offsetof(struct user32, regs.es):
 		*val = child->thread.es;
 		break;

 	R32(cs, cs);
 	R32(ss, ss);
 	R32(ebx, rbx);
 	R32(ecx, rcx);
 	R32(edx, rdx);
 	R32(edi, rdi);
 	R32(esi, rsi);
 	R32(ebp, rbp);
 	R32(eax, rax);
 	R32(orig_eax, orig_rax);
 	R32(eip, rip);
 	R32(eflags, eflags);
 	R32(esp, rsp);

 	case offsetof(struct user32, u_debugreg[0]):
 		*val = child->thread.debugreg0;
 		break;
 	case offsetof(struct user32, u_debugreg[1]):
 		*val = child->thread.debugreg1;
 		break;
 	case offsetof(struct user32, u_debugreg[2]):
 		*val = child->thread.debugreg2;
 		break;
 	case offsetof(struct user32, u_debugreg[3]):
 		*val = child->thread.debugreg3;
 		break;
 	case offsetof(struct user32, u_debugreg[6]):
 		*val = child->thread.debugreg6;
 		break;
 	case offsetof(struct user32, u_debugreg[7]):
 		*val = child->thread.debugreg7;
 		break;

 	default:
 		if (regno > sizeof(struct user32) || (regno & 3))
 			return -EIO;

 		/* Other dummy fields in the virtual user structure are ignored */
 		*val = 0;
 		break;
 	}
 	return 0;
 }

 #undef R32

 static long ptrace32_siginfo(unsigned request, u32 pid, u32 addr, u32 data)
 {
 	int ret;
 	compat_siginfo_t __user *si32 = compat_ptr(data);
 	siginfo_t ssi;
 	siginfo_t __user *si = compat_alloc_user_space(sizeof(siginfo_t));
 	if (request == PTRACE_SETSIGINFO) {
 		memset(&ssi, 0, sizeof(siginfo_t));
 		ret = copy_siginfo_from_user32(&ssi, si32);
 		if (ret)
 			return ret;
 		if (copy_to_user(si, &ssi, sizeof(siginfo_t)))
 			return -EFAULT;
 	}
 	ret = sys_ptrace(request, pid, addr, (unsigned long)si);
 	if (ret)
 		return ret;
 	if (request == PTRACE_GETSIGINFO) {
 		if (copy_from_user(&ssi, si, sizeof(siginfo_t)))
 			return -EFAULT;
 		ret = copy_siginfo_to_user32(si32, &ssi);
 	}
 	return ret;
 }

 #define COMPAT_GDT_ENTRY_TLS_MIN 6

 asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
 {
 	struct task_struct *child;
 	struct pt_regs *childregs;
 	void __user *datap = compat_ptr(data);
 	int ret;
 	__u32 val;

 	switch (request) {
 	case PTRACE_TRACEME:
 	case PTRACE_ATTACH:
 	case PTRACE_KILL:
 	case PTRACE_CONT:
 	case PTRACE_SINGLESTEP:
 	case PTRACE_DETACH:
 	case PTRACE_SYSCALL:
 	case PTRACE_OLDSETOPTIONS:
 	case PTRACE_SETOPTIONS:
 		return sys_ptrace(request, pid, addr, data);

 	default:
 		return -EINVAL;

 	case PTRACE_PEEKTEXT:
 	case PTRACE_PEEKDATA:
 	case PTRACE_POKEDATA:
 	case PTRACE_POKETEXT:
 	case PTRACE_POKEUSR:
 	case PTRACE_PEEKUSR:
 	case PTRACE_GETREGS:
 	case PTRACE_SETREGS:
 	case PTRACE_SETFPREGS:
 	case PTRACE_GETFPREGS:
 	case PTRACE_SETFPXREGS:
 	case PTRACE_GETFPXREGS:
 	case PTRACE_GETEVENTMSG:
 		break;

 	case PTRACE_SETSIGINFO:
 	case PTRACE_GETSIGINFO:
 		return ptrace32_siginfo(request, pid, addr, data);

 	case PTRACE_SET_THREAD_AREA:
 	case PTRACE_GET_THREAD_AREA:
 		return sys_ptrace(request, pid,
 			addr + GDT_ENTRY_TLS_MIN - COMPAT_GDT_ENTRY_TLS_MIN,
 			data);
 	}

 	child = ptrace_get_task_struct(pid);
 	if (IS_ERR(child))
 		return PTR_ERR(child);

 	ret = ptrace_check_attach(child, request == PTRACE_KILL);
 	if (ret < 0)
 		goto out;

 	childregs = task_pt_regs(child);

 	switch (request) {
 	case PTRACE_PEEKDATA:
 	case PTRACE_PEEKTEXT:
 		ret = 0;
 		if (access_process_vm(child, addr, &val, sizeof(u32), 0)!=sizeof(u32))
 			ret = -EIO;
 		else
 			ret = put_user(val, (unsigned int __user *)datap);
 		break;

 	case PTRACE_POKEDATA:
 	case PTRACE_POKETEXT:
 		ret = 0;
 		if (access_process_vm(child, addr, &data, sizeof(u32), 1)!=sizeof(u32))
 			ret = -EIO;
 		break;

 	case PTRACE_PEEKUSR:
 		ret = getreg32(child, addr, &val);
 		if (ret == 0)
 			ret = put_user(val, (__u32 __user *)datap);
 		break;

 	case PTRACE_POKEUSR:
 		ret = putreg32(child, addr, data);
 		break;

 	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 		int i;
 	  	if (!access_ok(VERIFY_WRITE, datap, 16*4)) {
 			ret = -EIO;
 			break;
 		}
 		ret = 0;
 		for ( i = 0; i <= 16*4 ; i += sizeof(__u32) ) {
 			getreg32(child, i, &val);
 			ret |= __put_user(val,(u32 __user *)datap);
 			datap += sizeof(u32);
 		}
 		break;
 	}

 	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 		unsigned long tmp;
 		int i;
 	  	if (!access_ok(VERIFY_READ, datap, 16*4)) {
 			ret = -EIO;
 			break;
 		}
 		ret = 0;
 		for ( i = 0; i <= 16*4; i += sizeof(u32) ) {
 			ret |= __get_user(tmp, (u32 __user *)datap);
 			putreg32(child, i, tmp);
 			datap += sizeof(u32);
 		}
 		break;
 	}

 	case PTRACE_GETFPREGS:
 		ret = -EIO;
 		if (!access_ok(VERIFY_READ, compat_ptr(data),
 			       sizeof(struct user_i387_struct)))
 			break;
 		save_i387_ia32(child, datap, childregs, 1);
 		ret = 0;
 			break;

 	case PTRACE_SETFPREGS:
 		ret = -EIO;
 		if (!access_ok(VERIFY_WRITE, datap,
 			       sizeof(struct user_i387_struct)))
 			break;
 		ret = 0;
 		/* don't check EFAULT to be bug-to-bug compatible to i386 */
 		restore_i387_ia32(child, datap, 1);
 		break;

 	case PTRACE_GETFPXREGS: {
 		struct user32_fxsr_struct __user *u = datap;
 		init_fpu(child);
 		ret = -EIO;
 		if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
 			break;
 			ret = -EFAULT;
 		if (__copy_to_user(u, &child->thread.i387.fxsave, sizeof(*u)))
 			break;
 		ret = __put_user(childregs->cs, &u->fcs);
 		ret |= __put_user(child->thread.ds, &u->fos);
 		break;
 	}
 	case PTRACE_SETFPXREGS: {
 		struct user32_fxsr_struct __user *u = datap;
 		unlazy_fpu(child);
 		ret = -EIO;
 		if (!access_ok(VERIFY_READ, u, sizeof(*u)))
 			break;
 		/* no checking to be bug-to-bug compatible with i386. */
 		/* but silence warning */
 		if (__copy_from_user(&child->thread.i387.fxsave, u, sizeof(*u)))
 			;
 		set_stopped_child_used_math(child);
 		child->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
 		ret = 0;
 		break;
 	}

 	case PTRACE_GETEVENTMSG:
 		ret = put_user(child->ptrace_message,(unsigned int __user *)compat_ptr(data));
 		break;

 	default:
 		BUG();
 	}

  out:
 	put_task_struct(child);
 	return ret;
 }
	/*
	* 32bit ptrace for x86-64.
	*
	* Copyright 2001,2002 Andi Kleen, SuSE Labs.
	* Some parts copied from arch/i386/kernel/ptrace.c. See that file for earlier
	* copyright.
	*
	* This allows to access 64bit processes too; but there is no way to see the extended
	* register contents.
	*/

	#include <linux/kernel.h>
	#include <linux/stddef.h>
	#include <linux/sched.h>
	#include <linux/syscalls.h>
	#include <linux/unistd.h>
	#include <linux/mm.h>
	#include <linux/err.h>
	#include <linux/ptrace.h>
	#include <asm/ptrace.h>
	#include <asm/compat.h>
	#include <asm/uaccess.h>
	#include <asm/user32.h>
	#include <asm/user.h>
	#include <asm/errno.h>
	#include <asm/debugreg.h>
	#include <asm/i387.h>
	#include <asm/fpu32.h>
	#include <asm/ia32.h>

	/*
	* Determines which flags the user has access to [1 = access, 0 = no access].
	* Prohibits changing ID(21), VIP(20), VIF(19), VM(17), IOPL(12-13), IF(9).
	* Also masks reserved bits (31-22, 15, 5, 3, 1).
	*/
	#define FLAG_MASK 0x54dd5UL

	#define R32(l,q) \
	case offsetof(struct user32, regs.l): stack[offsetof(struct pt_regs, q)/8] = val; break

	static int putreg32(struct task_struct *child, unsigned regno, u32 val)
	{
	int i;
	__u64 stack = (__u64 )task_pt_regs(child);

	switch (regno) {
	case offsetof(struct user32, regs.fs):
	if (val && (val & 3) != 3) return -EIO;
	child->thread.fsindex = val & 0xffff;
	break;
	case offsetof(struct user32, regs.gs):
	if (val && (val & 3) != 3) return -EIO;
	child->thread.gsindex = val & 0xffff;
	break;
	case offsetof(struct user32, regs.ds):
	if (val && (val & 3) != 3) return -EIO;
	child->thread.ds = val & 0xffff;
	break;
	case offsetof(struct user32, regs.es):
	child->thread.es = val & 0xffff;
	break;
	case offsetof(struct user32, regs.ss):
	if ((val & 3) != 3) return -EIO;
	stack[offsetof(struct pt_regs, ss)/8] = val & 0xffff;
	break;
	case offsetof(struct user32, regs.cs):
	if ((val & 3) != 3) return -EIO;
	stack[offsetof(struct pt_regs, cs)/8] = val & 0xffff;
	break;

	R32(ebx, rbx);
	R32(ecx, rcx);
	R32(edx, rdx);
	R32(edi, rdi);
	R32(esi, rsi);
	R32(ebp, rbp);
	R32(eax, rax);
	R32(orig_eax, orig_rax);
	R32(eip, rip);
	R32(esp, rsp);

	case offsetof(struct user32, regs.eflags): {
	__u64 *flags = &stack[offsetof(struct pt_regs, eflags)/8];
	val &= FLAG_MASK;
	flags = val \| (flags & ~FLAG_MASK);
	break;
	}

	case offsetof(struct user32, u_debugreg[4]):
	case offsetof(struct user32, u_debugreg[5]):
	return -EIO;

	case offsetof(struct user32, u_debugreg[0]):
	child->thread.debugreg0 = val;
	break;

	case offsetof(struct user32, u_debugreg[1]):
	child->thread.debugreg1 = val;
	break;

	case offsetof(struct user32, u_debugreg[2]):
	child->thread.debugreg2 = val;
	break;

	case offsetof(struct user32, u_debugreg[3]):
	child->thread.debugreg3 = val;
	break;

	case offsetof(struct user32, u_debugreg[6]):
	child->thread.debugreg6 = val;
	break;

	case offsetof(struct user32, u_debugreg[7]):
	val &= ~DR_CONTROL_RESERVED;
	/* See arch/i386/kernel/ptrace.c for an explanation of
	* this awkward check.*/
	for(i=0; i<4; i++)
	if ((0x5454 >> ((val >> (16 + 4*i)) & 0xf)) & 1)
	return -EIO;
	child->thread.debugreg7 = val;
	if (val)
	set_tsk_thread_flag(child, TIF_DEBUG);
	else
	clear_tsk_thread_flag(child, TIF_DEBUG);
	break;

	default:
	if (regno > sizeof(struct user32) \|\| (regno & 3))
	return -EIO;

	/* Other dummy fields in the virtual user structure are ignored */
	break;
	}
	return 0;
	}

	#undef R32

	#define R32(l,q) \
	case offsetof(struct user32, regs.l): *val = stack[offsetof(struct pt_regs, q)/8]; break

	static int getreg32(struct task_struct child, unsigned regno, u32 val)
	{
	__u64 stack = (__u64 )task_pt_regs(child);

	switch (regno) {
	case offsetof(struct user32, regs.fs):
	*val = child->thread.fsindex;
	break;
	case offsetof(struct user32, regs.gs):
	*val = child->thread.gsindex;
	break;
	case offsetof(struct user32, regs.ds):
	*val = child->thread.ds;
	break;
	case offsetof(struct user32, regs.es):
	*val = child->thread.es;
	break;

	R32(cs, cs);
	R32(ss, ss);
	R32(ebx, rbx);
	R32(ecx, rcx);
	R32(edx, rdx);
	R32(edi, rdi);
	R32(esi, rsi);
	R32(ebp, rbp);
	R32(eax, rax);
	R32(orig_eax, orig_rax);
	R32(eip, rip);
	R32(eflags, eflags);
	R32(esp, rsp);

	case offsetof(struct user32, u_debugreg[0]):
	*val = child->thread.debugreg0;
	break;
	case offsetof(struct user32, u_debugreg[1]):
	*val = child->thread.debugreg1;
	break;
	case offsetof(struct user32, u_debugreg[2]):
	*val = child->thread.debugreg2;
	break;
	case offsetof(struct user32, u_debugreg[3]):
	*val = child->thread.debugreg3;
	break;
	case offsetof(struct user32, u_debugreg[6]):
	*val = child->thread.debugreg6;
	break;
	case offsetof(struct user32, u_debugreg[7]):
	*val = child->thread.debugreg7;
	break;

	default:
	if (regno > sizeof(struct user32) \|\| (regno & 3))
	return -EIO;

	/* Other dummy fields in the virtual user structure are ignored */
	*val = 0;
	break;
	}
	return 0;
	}

	#undef R32

	static long ptrace32_siginfo(unsigned request, u32 pid, u32 addr, u32 data)
	{
	int ret;
	compat_siginfo_t __user *si32 = compat_ptr(data);
	siginfo_t ssi;
	siginfo_t __user *si = compat_alloc_user_space(sizeof(siginfo_t));
	if (request == PTRACE_SETSIGINFO) {
	memset(&ssi, 0, sizeof(siginfo_t));
	ret = copy_siginfo_from_user32(&ssi, si32);
	if (ret)
	return ret;
	if (copy_to_user(si, &ssi, sizeof(siginfo_t)))
	return -EFAULT;
	}
	ret = sys_ptrace(request, pid, addr, (unsigned long)si);
	if (ret)
	return ret;
	if (request == PTRACE_GETSIGINFO) {
	if (copy_from_user(&ssi, si, sizeof(siginfo_t)))
	return -EFAULT;
	ret = copy_siginfo_to_user32(si32, &ssi);
	}
	return ret;
	}

	#define COMPAT_GDT_ENTRY_TLS_MIN 6

	asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
	{
	struct task_struct *child;
	struct pt_regs *childregs;
	void __user *datap = compat_ptr(data);
	int ret;
	__u32 val;

	switch (request) {
	case PTRACE_TRACEME:
	case PTRACE_ATTACH:
	case PTRACE_KILL:
	case PTRACE_CONT:
	case PTRACE_SINGLESTEP:
	case PTRACE_DETACH:
	case PTRACE_SYSCALL:
	case PTRACE_OLDSETOPTIONS:
	case PTRACE_SETOPTIONS:
	return sys_ptrace(request, pid, addr, data);

	default:
	return -EINVAL;

	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
	case PTRACE_POKEDATA:
	case PTRACE_POKETEXT:
	case PTRACE_POKEUSR:
	case PTRACE_PEEKUSR:
	case PTRACE_GETREGS:
	case PTRACE_SETREGS:
	case PTRACE_SETFPREGS:
	case PTRACE_GETFPREGS:
	case PTRACE_SETFPXREGS:
	case PTRACE_GETFPXREGS:
	case PTRACE_GETEVENTMSG:
	break;

	case PTRACE_SETSIGINFO:
	case PTRACE_GETSIGINFO:
	return ptrace32_siginfo(request, pid, addr, data);

	case PTRACE_SET_THREAD_AREA:
	case PTRACE_GET_THREAD_AREA:
	return sys_ptrace(request, pid,
	addr + GDT_ENTRY_TLS_MIN - COMPAT_GDT_ENTRY_TLS_MIN,
	data);
	}

	child = ptrace_get_task_struct(pid);
	if (IS_ERR(child))
	return PTR_ERR(child);

	ret = ptrace_check_attach(child, request == PTRACE_KILL);
	if (ret < 0)
	goto out;

	childregs = task_pt_regs(child);

	switch (request) {
	case PTRACE_PEEKDATA:
	case PTRACE_PEEKTEXT:
	ret = 0;
	if (access_process_vm(child, addr, &val, sizeof(u32), 0)!=sizeof(u32))
	ret = -EIO;
	else
	ret = put_user(val, (unsigned int __user *)datap);
	break;

	case PTRACE_POKEDATA:
	case PTRACE_POKETEXT:
	ret = 0;
	if (access_process_vm(child, addr, &data, sizeof(u32), 1)!=sizeof(u32))
	ret = -EIO;
	break;

	case PTRACE_PEEKUSR:
	ret = getreg32(child, addr, &val);
	if (ret == 0)
	ret = put_user(val, (__u32 __user *)datap);
	break;

	case PTRACE_POKEUSR:
	ret = putreg32(child, addr, data);
	break;

	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
	int i;
	if (!access_ok(VERIFY_WRITE, datap, 16*4)) {
	ret = -EIO;
	break;
	}
	ret = 0;
	for ( i = 0; i <= 16*4 ; i += sizeof(__u32) ) {
	getreg32(child, i, &val);
	ret \|= __put_user(val,(u32 __user *)datap);
	datap += sizeof(u32);
	}
	break;
	}

	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
	unsigned long tmp;
	int i;
	if (!access_ok(VERIFY_READ, datap, 16*4)) {
	ret = -EIO;
	break;
	}
	ret = 0;
	for ( i = 0; i <= 16*4; i += sizeof(u32) ) {
	ret \|= __get_user(tmp, (u32 __user *)datap);
	putreg32(child, i, tmp);
	datap += sizeof(u32);
	}
	break;
	}

	case PTRACE_GETFPREGS:
	ret = -EIO;
	if (!access_ok(VERIFY_READ, compat_ptr(data),
	sizeof(struct user_i387_struct)))
	break;
	save_i387_ia32(child, datap, childregs, 1);
	ret = 0;
	break;

	case PTRACE_SETFPREGS:
	ret = -EIO;
	if (!access_ok(VERIFY_WRITE, datap,
	sizeof(struct user_i387_struct)))
	break;
	ret = 0;
	/* don't check EFAULT to be bug-to-bug compatible to i386 */
	restore_i387_ia32(child, datap, 1);
	break;

	case PTRACE_GETFPXREGS: {
	struct user32_fxsr_struct __user *u = datap;
	init_fpu(child);
	ret = -EIO;
	if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
	break;
	ret = -EFAULT;
	if (__copy_to_user(u, &child->thread.i387.fxsave, sizeof(*u)))
	break;
	ret = __put_user(childregs->cs, &u->fcs);
	ret \|= __put_user(child->thread.ds, &u->fos);
	break;
	}
	case PTRACE_SETFPXREGS: {
	struct user32_fxsr_struct __user *u = datap;
	unlazy_fpu(child);
	ret = -EIO;
	if (!access_ok(VERIFY_READ, u, sizeof(*u)))
	break;
	/* no checking to be bug-to-bug compatible with i386. */
	/* but silence warning */
	if (__copy_from_user(&child->thread.i387.fxsave, u, sizeof(*u)))
	;
	set_stopped_child_used_math(child);
	child->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
	ret = 0;
	break;
	}

	case PTRACE_GETEVENTMSG:
	ret = put_user(child->ptrace_message,(unsigned int __user *)compat_ptr(data));
	break;

	default:
	BUG();
	}

	out:
	put_task_struct(child);
	return ret;
	}