linux/arch/um/sys-x86_64/syscalls.c
Christoph Hellwig e28cbf2293 improve sys_newuname() for compat architectures
On an architecture that supports 32-bit compat we need to override the
reported machine in uname with the 32-bit value.  Instead of doing this
separately in every architecture introduce a COMPAT_UTS_MACHINE define in
<asm/compat.h> and apply it directly in sys_newuname().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:32 -08:00

103 lines
2.6 KiB
C

/*
* Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Copyright 2003 PathScale, Inc.
*
* Licensed under the GPL
*/
#include "linux/linkage.h"
#include "linux/personality.h"
#include "linux/utsname.h"
#include "asm/prctl.h" /* XXX This should get the constants from libc */
#include "asm/uaccess.h"
#include "os.h"
long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr)
{
unsigned long *ptr = addr, 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 (code) {
case ARCH_SET_FS:
case ARCH_SET_GS:
ret = restore_registers(pid, &current->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, code, ptr);
if (ret)
return ret;
switch (code) {
case ARCH_SET_FS:
current->thread.arch.fs = (unsigned long) ptr;
ret = save_registers(pid, &current->thread.regs.regs);
break;
case ARCH_SET_GS:
ret = save_registers(pid, &current->thread.regs.regs);
break;
case ARCH_GET_FS:
ret = put_user(tmp, addr);
break;
case ARCH_GET_GS:
ret = put_user(tmp, addr);
break;
}
return ret;
}
long sys_arch_prctl(int code, unsigned long addr)
{
return arch_prctl(current, code, (unsigned long __user *) addr);
}
long sys_clone(unsigned long clone_flags, unsigned long newsp,
void __user *parent_tid, void __user *child_tid)
{
long ret;
if (!newsp)
newsp = UPT_SP(&current->thread.regs.regs);
current->thread.forking = 1;
ret = do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
child_tid);
current->thread.forking = 0;
return ret;
}
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);
}