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
arch_prctl(struct task_struct * task,int code,unsigned long __user * addr)15 long 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, ¤t->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, ¤t->thread.regs.regs);
62 break;
63 case ARCH_SET_GS:
64 ret = save_registers(pid, ¤t->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
sys_arch_prctl(int code,unsigned long addr)77 long sys_arch_prctl(int code, unsigned long addr)
78 {
79 return arch_prctl(current, code, (unsigned long __user *) addr);
80 }
81
sys_clone(unsigned long clone_flags,unsigned long newsp,void __user * parent_tid,void __user * child_tid)82 long 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(¤t->thread.regs.regs);
89 current->thread.forking = 1;
90 ret = do_fork(clone_flags, newsp, ¤t->thread.regs, 0, parent_tid,
91 child_tid);
92 current->thread.forking = 0;
93 return ret;
94 }
95
arch_switch_to(struct task_struct * to)96 void 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 }
103