90 lines
2.3 KiB
C
90 lines
2.3 KiB
C
|
/*
|
||
|
|
* Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
|
||
|
|
* Copyright 2003 PathScale, Inc.
|
||
|
|
*
|
||
|
|
* Licensed under the GPL
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/sched/mm.h>
|
||
|
|
#include <linux/syscalls.h>
|
||
|
|
#include <linux/uaccess.h>
|
||
|
|
#include <asm/prctl.h> /* XXX This should get the constants from libc */
|
||
|
|
#include <os.h>
|
||
|
|
|
||
|
|
long arch_prctl(struct task_struct *task, int option,
|
||
|
|
unsigned long __user *arg2)
|
||
|
|
{
|
||
|
|
unsigned long *ptr = arg2, tmp;
|
||
|
|
long ret;
|
||
|
|
int pid = task->mm->context.id.u.pid;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
|
||
|
|
* be safe), we need to call arch_prctl on the host because
|
||
|
|
* setting %fs may result in something else happening (like a
|
||
|
|
* GDT or thread.fs being set instead). So, we let the host
|
||
|
|
* fiddle the registers and thread struct and restore the
|
||
|
|
* registers afterwards.
|
||
|
|
*
|
||
|
|
* So, the saved registers are stored to the process (this
|
||
|
|
* needed because a stub may have been the last thing to run),
|
||
|
|
* arch_prctl is run on the host, then the registers are read
|
||
|
|
* back.
|
||
|
|
*/
|
||
|
|
switch (option) {
|
||
|
|
case ARCH_SET_FS:
|
||
|
|
case ARCH_SET_GS:
|
||
|
|
ret = restore_registers(pid, ¤t->thread.regs.regs);
|
||
|
|
if (ret)
|
||
|
|
return ret;
|
||
|
|
break;
|
||
|
|
case ARCH_GET_FS:
|
||
|
|
case ARCH_GET_GS:
|
||
|
|
/*
|
||
|
|
* With these two, we read to a local pointer and
|
||
|
|
* put_user it to the userspace pointer that we were
|
||
|
|
* given. If addr isn't valid (because it hasn't been
|
||
|
|
* faulted in or is just bogus), we want put_user to
|
||
|
|
* fault it in (or return -EFAULT) instead of having
|
||
|
|
* the host return -EFAULT.
|
||
|
|
*/
|
||
|
|
ptr = &tmp;
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = os_arch_prctl(pid, option, ptr);
|
||
|
|
if (ret)
|
||
|
|
return ret;
|
||
|
|
|
||
|
|
switch (option) {
|
||
|
|
case ARCH_SET_FS:
|
||
|
|
current->thread.arch.fs = (unsigned long) ptr;
|
||
|
|
ret = save_registers(pid, ¤t->thread.regs.regs);
|
||
|
|
break;
|
||
|
|
case ARCH_SET_GS:
|
||
|
|
ret = save_registers(pid, ¤t->thread.regs.regs);
|
||
|
|
break;
|
||
|
|
case ARCH_GET_FS:
|
||
|
|
ret = put_user(tmp, arg2);
|
||
|
|
break;
|
||
|
|
case ARCH_GET_GS:
|
||
|
|
ret = put_user(tmp, arg2);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
|
||
|
|
{
|
||
|
|
return arch_prctl(current, option, (unsigned long __user *) arg2);
|
||
|
|
}
|
||
|
|
|
||
|
|
void arch_switch_to(struct task_struct *to)
|
||
|
|
{
|
||
|
|
if ((to->thread.arch.fs == 0) || (to->mm == NULL))
|
||
|
|
return;
|
||
|
|
|
||
|
|
arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
|
||
|
|
}
|