freebsd-dev/sys/i386/include/proc.h
Konstantin Belousov 9719da13e7 When doing rfork(0), i.e. separating curproc VM from any other user of
the same vmspace, decrement the reference count of the shared LDT instead
of a newly-made copy. Code factually removed LDT from the process that
did rfork(0).

Introduce user_ldt_deref() function that does decrement of refcount for
the struct proc_ldt, and call it in the rfork(0) case on the shared LDT.

Reviewed by:	jhb
MFC after:	1 week
2008-09-12 09:53:29 +00:00

81 lines
2.7 KiB
C

/*-
* Copyright (c) 1991 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)proc.h 7.1 (Berkeley) 5/15/91
* $FreeBSD$
*/
#ifndef _MACHINE_PROC_H_
#define _MACHINE_PROC_H_
#include <machine/segments.h>
struct proc_ldt {
caddr_t ldt_base;
int ldt_len;
int ldt_refcnt;
u_long ldt_active;
struct segment_descriptor ldt_sd;
};
/*
* Machine-dependent part of the proc structure for i386.
* Table of MD locks:
* t - Descriptor tables lock
*/
struct mdthread {
int md_spinlock_count; /* (k) */
register_t md_saved_flags; /* (k) */
};
struct mdproc {
struct proc_ldt *md_ldt; /* (t) per-process ldt */
};
#ifdef _KERNEL
/* Get the current kernel thread stack usage. */
#define GET_STACK_USAGE(total, used) do { \
struct thread *td = curthread; \
(total) = td->td_kstack_pages * PAGE_SIZE; \
(used) = (char *)td->td_kstack + \
td->td_kstack_pages * PAGE_SIZE - \
(char *)&td; \
} while (0)
void set_user_ldt(struct mdproc *);
struct proc_ldt *user_ldt_alloc(struct mdproc *, int);
void user_ldt_free(struct thread *);
void user_ldt_deref(struct proc_ldt *pldt);
extern struct mtx dt_lock;
#endif /* _KERNEL */
#endif /* !_MACHINE_PROC_H_ */