Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
ba180fd4 | 2 | * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
3 | * Copyright 2003 PathScale, Inc. |
4 | * | |
5 | * Licensed under the GPL | |
6 | */ | |
7 | ||
d2ce4e92 | 8 | #include <linux/sched.h> |
7017f42f | 9 | #include <linux/uaccess.h> |
d2ce4e92 AV |
10 | #include <asm/prctl.h> /* XXX This should get the constants from libc */ |
11 | #include <os.h> | |
1da177e4 | 12 | |
77bf4400 | 13 | long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr) |
1da177e4 | 14 | { |
ba180fd4 | 15 | unsigned long *ptr = addr, tmp; |
f355559c | 16 | long ret; |
6c738ffa | 17 | int pid = task->mm->context.id.u.pid; |
1da177e4 | 18 | |
f355559c JD |
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 | |
6e6d74cf JD |
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. | |
f355559c JD |
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 | */ | |
ba180fd4 | 32 | switch (code) { |
1da177e4 | 33 | case ARCH_SET_FS: |
f767b02f | 34 | case ARCH_SET_GS: |
3e6f2ac4 JD |
35 | ret = restore_registers(pid, ¤t->thread.regs.regs); |
36 | if (ret) | |
37 | return ret; | |
ba180fd4 JD |
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 | } | |
f355559c | 51 | |
ba180fd4 JD |
52 | ret = os_arch_prctl(pid, code, ptr); |
53 | if (ret) | |
54 | return ret; | |
f355559c | 55 | |
ba180fd4 | 56 | switch (code) { |
f355559c | 57 | case ARCH_SET_FS: |
44f5c4ce | 58 | current->thread.arch.fs = (unsigned long) ptr; |
3e6f2ac4 | 59 | ret = save_registers(pid, ¤t->thread.regs.regs); |
44f5c4ce | 60 | break; |
f355559c | 61 | case ARCH_SET_GS: |
3e6f2ac4 | 62 | ret = save_registers(pid, ¤t->thread.regs.regs); |
f767b02f | 63 | break; |
1da177e4 | 64 | case ARCH_GET_FS: |
f355559c | 65 | ret = put_user(tmp, addr); |
ba180fd4 | 66 | break; |
1da177e4 | 67 | case ARCH_GET_GS: |
f355559c | 68 | ret = put_user(tmp, addr); |
ba180fd4 | 69 | break; |
1da177e4 LT |
70 | } |
71 | ||
f355559c | 72 | return ret; |
1da177e4 | 73 | } |
1da177e4 LT |
74 | |
75 | long sys_arch_prctl(int code, unsigned long addr) | |
76 | { | |
77bf4400 | 77 | return arch_prctl(current, code, (unsigned long __user *) addr); |
1da177e4 LT |
78 | } |
79 | ||
291248fd | 80 | void arch_switch_to(struct task_struct *to) |
f355559c | 81 | { |
ba180fd4 JD |
82 | if ((to->thread.arch.fs == 0) || (to->mm == NULL)) |
83 | return; | |
f355559c | 84 | |
ba180fd4 | 85 | arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs); |
1da177e4 | 86 | } |