5730afc9b6
kernel. When access restrictions are added to a page table entry, we flush the corresponding virtual address mapping from the TLB. In contrast, when access restrictions are removed from a page table entry, we do not flush the virtual address mapping from the TLB. This is exactly as recommended in AMD's documentation. In effect, when access restrictions are removed from a page table entry, AMD's MMUs will transparently refresh a stale TLB entry. In short, this saves us from having to perform potentially costly TLB flushes. In contrast, Intel's MMUs are allowed to generate a spurious page fault based upon the stale TLB entry. Usually, such spurious page faults are handled by vm_fault() without incident. However, when we are executing no-fault sections of the kernel, we are not allowed to execute vm_fault(). This change introduces special-case handling for spurious page faults that occur in no-fault sections of the kernel. In collaboration with: kib Tested by: gibbs (an earlier version) I would also like to acknowledge Hiroki Sato's assistance in diagnosing this problem. MFC after: 1 week
90 lines
2.9 KiB
C
90 lines
2.9 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) */
|
|
register_t md_spurflt_addr; /* (k) Spurious page fault address. */
|
|
};
|
|
|
|
struct mdproc {
|
|
struct proc_ldt *md_ldt; /* (t) per-process ldt */
|
|
};
|
|
|
|
#define KINFO_PROC_SIZE 768
|
|
|
|
#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;
|
|
|
|
struct syscall_args {
|
|
u_int code;
|
|
struct sysent *callp;
|
|
register_t args[8];
|
|
int narg;
|
|
};
|
|
#endif /* _KERNEL */
|
|
|
|
#endif /* !_MACHINE_PROC_H_ */
|