44f5c4ced6
In my previous x86_64 thread fix, I forgot to initialize thread.arch.fs in arch_prctl. A process calling arch_prctl to set %fs would lose it on the next context switch. It also turns out that you can switch to a process which is in the process of exiting and which has lost its mm. In this case, it's worse than useless to try to call arch_prctl on the host process. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
151 lines
3.8 KiB
C
151 lines
3.8 KiB
C
/*
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* Copyright 2003 PathScale, Inc.
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*
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* Licensed under the GPL
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*/
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#include "linux/linkage.h"
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#include "linux/slab.h"
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#include "linux/shm.h"
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#include "linux/utsname.h"
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#include "linux/personality.h"
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#include "asm/uaccess.h"
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#define __FRAME_OFFSETS
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#include "asm/ptrace.h"
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#include "asm/unistd.h"
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#include "asm/prctl.h" /* XXX This should get the constants from libc */
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#include "choose-mode.h"
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#include "kern.h"
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#include "os.h"
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asmlinkage long sys_uname64(struct new_utsname __user * name)
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{
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int err;
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down_read(&uts_sem);
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err = copy_to_user(name, utsname(), sizeof (*name));
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up_read(&uts_sem);
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if (personality(current->personality) == PER_LINUX32)
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err |= copy_to_user(&name->machine, "i686", 5);
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return err ? -EFAULT : 0;
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}
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#ifdef CONFIG_MODE_TT
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extern long arch_prctl(int code, unsigned long addr);
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static long arch_prctl_tt(int code, unsigned long addr)
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{
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unsigned long tmp;
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long ret;
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switch(code){
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case ARCH_SET_GS:
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case ARCH_SET_FS:
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ret = arch_prctl(code, addr);
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break;
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case ARCH_GET_FS:
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case ARCH_GET_GS:
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ret = arch_prctl(code, (unsigned long) &tmp);
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if(!ret)
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ret = put_user(tmp, (long __user *)addr);
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return(ret);
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}
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#endif
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#ifdef CONFIG_MODE_SKAS
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long arch_prctl_skas(struct task_struct *task, int code,
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unsigned long __user *addr)
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{
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unsigned long *ptr = addr, tmp;
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long ret;
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int pid = task->mm->context.skas.id.u.pid;
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/*
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* With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
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* be safe), we need to call arch_prctl on the host because
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* setting %fs may result in something else happening (like a
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* GDT or thread.fs being set instead). So, we let the host
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* fiddle the registers and thread struct and restore the
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* registers afterwards.
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*
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* So, the saved registers are stored to the process (this
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* needed because a stub may have been the last thing to run),
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* arch_prctl is run on the host, then the registers are read
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* back.
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*/
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switch(code){
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case ARCH_SET_FS:
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case ARCH_SET_GS:
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restore_registers(pid, ¤t->thread.regs.regs);
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break;
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case ARCH_GET_FS:
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case ARCH_GET_GS:
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/*
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* With these two, we read to a local pointer and
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* put_user it to the userspace pointer that we were
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* given. If addr isn't valid (because it hasn't been
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* faulted in or is just bogus), we want put_user to
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* fault it in (or return -EFAULT) instead of having
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* the host return -EFAULT.
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*/
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ptr = &tmp;
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}
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ret = os_arch_prctl(pid, code, ptr);
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if(ret)
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return ret;
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switch(code){
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case ARCH_SET_FS:
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current->thread.arch.fs = (unsigned long) ptr;
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save_registers(pid, ¤t->thread.regs.regs);
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break;
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case ARCH_SET_GS:
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save_registers(pid, ¤t->thread.regs.regs);
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break;
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case ARCH_GET_FS:
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ret = put_user(tmp, addr);
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break;
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case ARCH_GET_GS:
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ret = put_user(tmp, addr);
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break;
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}
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return ret;
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}
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#endif
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long sys_arch_prctl(int code, unsigned long addr)
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{
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return CHOOSE_MODE_PROC(arch_prctl_tt, arch_prctl_skas, current, code,
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(unsigned long __user *) addr);
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}
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long sys_clone(unsigned long clone_flags, unsigned long newsp,
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void __user *parent_tid, void __user *child_tid)
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{
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long ret;
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if (!newsp)
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newsp = UPT_SP(¤t->thread.regs.regs);
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current->thread.forking = 1;
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ret = do_fork(clone_flags, newsp, ¤t->thread.regs, 0, parent_tid,
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child_tid);
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current->thread.forking = 0;
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return ret;
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}
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void arch_switch_to_skas(struct task_struct *from, struct task_struct *to)
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{
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if((to->thread.arch.fs == 0) || (to->mm == NULL))
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return;
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arch_prctl_skas(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
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}
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