1/*
 2 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 3 * Copyright 2003 PathScale, Inc.
 4 *
 5 * Licensed under the GPL
 6 */
 7
 8#include <linux/sched.h>
 9#include <linux/uaccess.h>
10#include <asm/prctl.h> /* XXX This should get the constants from libc */
11#include <os.h>
 
 
12
13long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr)
14{
15	unsigned long *ptr = addr, tmp;
16	long ret;
17	int pid = task->mm->context.id.u.pid;
18
19	/*
20	 * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
21	 * be safe), we need to call arch_prctl on the host because
22	 * setting %fs may result in something else happening (like a
23	 * GDT or thread.fs being set instead).  So, we let the host
24	 * fiddle the registers and thread struct and restore the
25	 * registers afterwards.
26	 *
27	 * So, the saved registers are stored to the process (this
28	 * needed because a stub may have been the last thing to run),
29	 * arch_prctl is run on the host, then the registers are read
30	 * back.
31	 */
32	switch (code) {
33	case ARCH_SET_FS:
34	case ARCH_SET_GS:
35		ret = restore_registers(pid, &current->thread.regs.regs);
36		if (ret)
37			return ret;
38		break;
39	case ARCH_GET_FS:
40	case ARCH_GET_GS:
41		/*
42		 * With these two, we read to a local pointer and
43		 * put_user it to the userspace pointer that we were
44		 * given.  If addr isn't valid (because it hasn't been
45		 * faulted in or is just bogus), we want put_user to
46		 * fault it in (or return -EFAULT) instead of having
47		 * the host return -EFAULT.
48		 */
49		ptr = &tmp;
50	}
51
52	ret = os_arch_prctl(pid, code, ptr);
53	if (ret)
54		return ret;
55
56	switch (code) {
57	case ARCH_SET_FS:
58		current->thread.arch.fs = (unsigned long) ptr;
59		ret = save_registers(pid, &current->thread.regs.regs);
60		break;
61	case ARCH_SET_GS:
62		ret = save_registers(pid, &current->thread.regs.regs);
63		break;
64	case ARCH_GET_FS:
65		ret = put_user(tmp, addr);
66		break;
67	case ARCH_GET_GS:
68		ret = put_user(tmp, addr);
69		break;
70	}
71
72	return ret;
73}
74
75long sys_arch_prctl(int code, unsigned long addr)
76{
77	return arch_prctl(current, code, (unsigned long __user *) addr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
78}
79
80void arch_switch_to(struct task_struct *to)
81{
82	if ((to->thread.arch.fs == 0) || (to->mm == NULL))
83		return;
84
85	arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
86}

  1/*
  2 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3 * Copyright 2003 PathScale, Inc.
  4 *
  5 * Licensed under the GPL
  6 */
  7
  8#include "linux/linkage.h"
  9#include "linux/personality.h"
 10#include "linux/utsname.h"
 11#include "asm/prctl.h" /* XXX This should get the constants from libc */
 12#include "asm/uaccess.h"
 13#include "os.h"
 14
 15long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr)
 16{
 17	unsigned long *ptr = addr, tmp;
 18	long ret;
 19	int pid = task->mm->context.id.u.pid;
 20
 21	/*
 22	 * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
 23	 * be safe), we need to call arch_prctl on the host because
 24	 * setting %fs may result in something else happening (like a
 25	 * GDT or thread.fs being set instead).  So, we let the host
 26	 * fiddle the registers and thread struct and restore the
 27	 * registers afterwards.
 28	 *
 29	 * So, the saved registers are stored to the process (this
 30	 * needed because a stub may have been the last thing to run),
 31	 * arch_prctl is run on the host, then the registers are read
 32	 * back.
 33	 */
 34	switch (code) {
 35	case ARCH_SET_FS:
 36	case ARCH_SET_GS:
 37		ret = restore_registers(pid, &current->thread.regs.regs);
 38		if (ret)
 39			return ret;
 40		break;
 41	case ARCH_GET_FS:
 42	case ARCH_GET_GS:
 43		/*
 44		 * With these two, we read to a local pointer and
 45		 * put_user it to the userspace pointer that we were
 46		 * given.  If addr isn't valid (because it hasn't been
 47		 * faulted in or is just bogus), we want put_user to
 48		 * fault it in (or return -EFAULT) instead of having
 49		 * the host return -EFAULT.
 50		 */
 51		ptr = &tmp;
 52	}
 53
 54	ret = os_arch_prctl(pid, code, ptr);
 55	if (ret)
 56		return ret;
 57
 58	switch (code) {
 59	case ARCH_SET_FS:
 60		current->thread.arch.fs = (unsigned long) ptr;
 61		ret = save_registers(pid, &current->thread.regs.regs);
 62		break;
 63	case ARCH_SET_GS:
 64		ret = save_registers(pid, &current->thread.regs.regs);
 65		break;
 66	case ARCH_GET_FS:
 67		ret = put_user(tmp, addr);
 68		break;
 69	case ARCH_GET_GS:
 70		ret = put_user(tmp, addr);
 71		break;
 72	}
 73
 74	return ret;
 75}
 76
 77long sys_arch_prctl(int code, unsigned long addr)
 78{
 79	return arch_prctl(current, code, (unsigned long __user *) addr);
 80}
 81
 82long sys_clone(unsigned long clone_flags, unsigned long newsp,
 83	       void __user *parent_tid, void __user *child_tid)
 84{
 85	long ret;
 86
 87	if (!newsp)
 88		newsp = UPT_SP(&current->thread.regs.regs);
 89	current->thread.forking = 1;
 90	ret = do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
 91		      child_tid);
 92	current->thread.forking = 0;
 93	return ret;
 94}
 95
 96void arch_switch_to(struct task_struct *to)
 97{
 98	if ((to->thread.arch.fs == 0) || (to->mm == NULL))
 99		return;
100
101	arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
102}