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Commit | Line | Data |
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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> |
589ee628 | 9 | #include <linux/sched/mm.h> |
ff3f097e | 10 | #include <linux/syscalls.h> |
7017f42f | 11 | #include <linux/uaccess.h> |
d2ce4e92 AV |
12 | #include <asm/prctl.h> /* XXX This should get the constants from libc */ |
13 | #include <os.h> | |
1da177e4 | 14 | |
d582799f | 15 | long arch_prctl(struct task_struct *task, int option, |
17a6e1b8 | 16 | unsigned long __user *arg2) |
1da177e4 | 17 | { |
17a6e1b8 | 18 | unsigned long *ptr = arg2, tmp; |
f355559c | 19 | long ret; |
6c738ffa | 20 | int pid = task->mm->context.id.u.pid; |
1da177e4 | 21 | |
f355559c JD |
22 | /* |
23 | * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to | |
24 | * be safe), we need to call arch_prctl on the host because | |
25 | * setting %fs may result in something else happening (like a | |
6e6d74cf JD |
26 | * GDT or thread.fs being set instead). So, we let the host |
27 | * fiddle the registers and thread struct and restore the | |
28 | * registers afterwards. | |
f355559c JD |
29 | * |
30 | * So, the saved registers are stored to the process (this | |
31 | * needed because a stub may have been the last thing to run), | |
32 | * arch_prctl is run on the host, then the registers are read | |
33 | * back. | |
34 | */ | |
dd93938a | 35 | switch (option) { |
1da177e4 | 36 | case ARCH_SET_FS: |
f767b02f | 37 | case ARCH_SET_GS: |
3e6f2ac4 JD |
38 | ret = restore_registers(pid, ¤t->thread.regs.regs); |
39 | if (ret) | |
40 | return ret; | |
ba180fd4 JD |
41 | break; |
42 | case ARCH_GET_FS: | |
43 | case ARCH_GET_GS: | |
44 | /* | |
45 | * With these two, we read to a local pointer and | |
46 | * put_user it to the userspace pointer that we were | |
47 | * given. If addr isn't valid (because it hasn't been | |
48 | * faulted in or is just bogus), we want put_user to | |
49 | * fault it in (or return -EFAULT) instead of having | |
50 | * the host return -EFAULT. | |
51 | */ | |
52 | ptr = &tmp; | |
53 | } | |
f355559c | 54 | |
dd93938a | 55 | ret = os_arch_prctl(pid, option, ptr); |
ba180fd4 JD |
56 | if (ret) |
57 | return ret; | |
f355559c | 58 | |
dd93938a | 59 | switch (option) { |
f355559c | 60 | case ARCH_SET_FS: |
44f5c4ce | 61 | current->thread.arch.fs = (unsigned long) ptr; |
3e6f2ac4 | 62 | ret = save_registers(pid, ¤t->thread.regs.regs); |
44f5c4ce | 63 | break; |
f355559c | 64 | case ARCH_SET_GS: |
3e6f2ac4 | 65 | ret = save_registers(pid, ¤t->thread.regs.regs); |
f767b02f | 66 | break; |
1da177e4 | 67 | case ARCH_GET_FS: |
17a6e1b8 | 68 | ret = put_user(tmp, arg2); |
ba180fd4 | 69 | break; |
1da177e4 | 70 | case ARCH_GET_GS: |
17a6e1b8 | 71 | ret = put_user(tmp, arg2); |
ba180fd4 | 72 | break; |
1da177e4 LT |
73 | } |
74 | ||
f355559c | 75 | return ret; |
1da177e4 | 76 | } |
1da177e4 | 77 | |
17a6e1b8 | 78 | SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2) |
1da177e4 | 79 | { |
17a6e1b8 | 80 | return arch_prctl(current, option, (unsigned long __user *) arg2); |
1da177e4 LT |
81 | } |
82 | ||
291248fd | 83 | void arch_switch_to(struct task_struct *to) |
f355559c | 84 | { |
ba180fd4 JD |
85 | if ((to->thread.arch.fs == 0) || (to->mm == NULL)) |
86 | return; | |
f355559c | 87 | |
ba180fd4 | 88 | arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs); |
1da177e4 | 89 | } |