792 lines
20 KiB
C
792 lines
20 KiB
C
/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)sys_machdep.c 5.5 (Berkeley) 1/19/91
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_capsicum.h"
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#include "opt_kstack_pages.h"
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#include <sys/param.h>
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#include <sys/capsicum.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/smp.h>
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#include <sys/sysproto.h>
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#include <vm/vm.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_extern.h>
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#include <machine/cpu.h>
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#include <machine/pcb.h>
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#include <machine/pcb_ext.h>
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#include <machine/proc.h>
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#include <machine/sysarch.h>
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#include <security/audit/audit.h>
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#include <vm/vm_kern.h> /* for kernel_map */
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#define MAX_LD 8192
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#define LD_PER_PAGE 512
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#define NEW_MAX_LD(num) rounddown2(num + LD_PER_PAGE, LD_PER_PAGE)
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#define SIZE_FROM_LARGEST_LD(num) (NEW_MAX_LD(num) << 3)
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#define NULL_LDT_BASE ((caddr_t)NULL)
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#ifdef SMP
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static void set_user_ldt_rv(struct vmspace *vmsp);
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#endif
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static int i386_set_ldt_data(struct thread *, int start, int num,
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union descriptor *descs);
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static int i386_ldt_grow(struct thread *td, int len);
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void
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fill_based_sd(struct segment_descriptor *sdp, uint32_t base)
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{
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sdp->sd_lobase = base & 0xffffff;
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sdp->sd_hibase = (base >> 24) & 0xff;
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sdp->sd_lolimit = 0xffff; /* 4GB limit, wraps around */
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sdp->sd_hilimit = 0xf;
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sdp->sd_type = SDT_MEMRWA;
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sdp->sd_dpl = SEL_UPL;
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sdp->sd_p = 1;
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sdp->sd_xx = 0;
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sdp->sd_def32 = 1;
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sdp->sd_gran = 1;
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}
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#ifndef _SYS_SYSPROTO_H_
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struct sysarch_args {
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int op;
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char *parms;
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};
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#endif
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int
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sysarch(td, uap)
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struct thread *td;
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register struct sysarch_args *uap;
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{
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int error;
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union descriptor *lp;
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union {
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struct i386_ldt_args largs;
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struct i386_ioperm_args iargs;
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struct i386_get_xfpustate xfpu;
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} kargs;
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uint32_t base;
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struct segment_descriptor sd, *sdp;
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AUDIT_ARG_CMD(uap->op);
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#ifdef CAPABILITY_MODE
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/*
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* When adding new operations, add a new case statement here to
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* explicitly indicate whether or not the operation is safe to
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* perform in capability mode.
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*/
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if (IN_CAPABILITY_MODE(td)) {
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switch (uap->op) {
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case I386_GET_LDT:
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case I386_SET_LDT:
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case I386_GET_IOPERM:
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case I386_GET_FSBASE:
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case I386_SET_FSBASE:
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case I386_GET_GSBASE:
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case I386_SET_GSBASE:
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case I386_GET_XFPUSTATE:
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break;
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case I386_SET_IOPERM:
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default:
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_CAPFAIL))
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ktrcapfail(CAPFAIL_SYSCALL, NULL, NULL);
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#endif
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return (ECAPMODE);
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}
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}
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#endif
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switch (uap->op) {
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case I386_GET_IOPERM:
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case I386_SET_IOPERM:
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if ((error = copyin(uap->parms, &kargs.iargs,
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sizeof(struct i386_ioperm_args))) != 0)
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return (error);
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break;
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case I386_GET_LDT:
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case I386_SET_LDT:
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if ((error = copyin(uap->parms, &kargs.largs,
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sizeof(struct i386_ldt_args))) != 0)
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return (error);
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if (kargs.largs.num > MAX_LD || kargs.largs.num <= 0)
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return (EINVAL);
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break;
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case I386_GET_XFPUSTATE:
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if ((error = copyin(uap->parms, &kargs.xfpu,
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sizeof(struct i386_get_xfpustate))) != 0)
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return (error);
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break;
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default:
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break;
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}
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switch(uap->op) {
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case I386_GET_LDT:
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error = i386_get_ldt(td, &kargs.largs);
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break;
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case I386_SET_LDT:
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if (kargs.largs.descs != NULL) {
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lp = (union descriptor *)malloc(
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kargs.largs.num * sizeof(union descriptor),
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M_TEMP, M_WAITOK);
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error = copyin(kargs.largs.descs, lp,
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kargs.largs.num * sizeof(union descriptor));
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if (error == 0)
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error = i386_set_ldt(td, &kargs.largs, lp);
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free(lp, M_TEMP);
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} else {
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error = i386_set_ldt(td, &kargs.largs, NULL);
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}
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break;
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case I386_GET_IOPERM:
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error = i386_get_ioperm(td, &kargs.iargs);
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if (error == 0)
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error = copyout(&kargs.iargs, uap->parms,
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sizeof(struct i386_ioperm_args));
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break;
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case I386_SET_IOPERM:
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error = i386_set_ioperm(td, &kargs.iargs);
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break;
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case I386_VM86:
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error = vm86_sysarch(td, uap->parms);
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break;
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case I386_GET_FSBASE:
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sdp = &td->td_pcb->pcb_fsd;
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base = sdp->sd_hibase << 24 | sdp->sd_lobase;
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error = copyout(&base, uap->parms, sizeof(base));
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break;
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case I386_SET_FSBASE:
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error = copyin(uap->parms, &base, sizeof(base));
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if (error == 0) {
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/*
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* Construct a descriptor and store it in the pcb for
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* the next context switch. Also store it in the gdt
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* so that the load of tf_fs into %fs will activate it
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* at return to userland.
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*/
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fill_based_sd(&sd, base);
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critical_enter();
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td->td_pcb->pcb_fsd = sd;
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PCPU_GET(fsgs_gdt)[0] = sd;
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critical_exit();
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td->td_frame->tf_fs = GSEL(GUFS_SEL, SEL_UPL);
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}
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break;
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case I386_GET_GSBASE:
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sdp = &td->td_pcb->pcb_gsd;
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base = sdp->sd_hibase << 24 | sdp->sd_lobase;
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error = copyout(&base, uap->parms, sizeof(base));
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break;
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case I386_SET_GSBASE:
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error = copyin(uap->parms, &base, sizeof(base));
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if (error == 0) {
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/*
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* Construct a descriptor and store it in the pcb for
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* the next context switch. Also store it in the gdt
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* because we have to do a load_gs() right now.
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*/
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fill_based_sd(&sd, base);
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critical_enter();
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td->td_pcb->pcb_gsd = sd;
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PCPU_GET(fsgs_gdt)[1] = sd;
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critical_exit();
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load_gs(GSEL(GUGS_SEL, SEL_UPL));
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}
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break;
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case I386_GET_XFPUSTATE:
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if (kargs.xfpu.len > cpu_max_ext_state_size -
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sizeof(union savefpu))
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return (EINVAL);
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npxgetregs(td);
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error = copyout((char *)(get_pcb_user_save_td(td) + 1),
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kargs.xfpu.addr, kargs.xfpu.len);
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break;
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default:
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error = EINVAL;
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break;
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}
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return (error);
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}
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int
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i386_extend_pcb(struct thread *td)
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{
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int i, offset;
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u_long *addr;
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struct pcb_ext *ext;
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struct soft_segment_descriptor ssd = {
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0, /* segment base address (overwritten) */
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ctob(IOPAGES + 1) - 1, /* length */
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SDT_SYS386TSS, /* segment type */
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0, /* priority level */
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1, /* descriptor present */
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0, 0,
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0, /* default 32 size */
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0 /* granularity */
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};
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ext = (struct pcb_ext *)kmem_malloc(kernel_arena, ctob(IOPAGES+1),
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M_WAITOK | M_ZERO);
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/* -16 is so we can convert a trapframe into vm86trapframe inplace */
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ext->ext_tss.tss_esp0 = (vm_offset_t)td->td_pcb - 16;
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ext->ext_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL);
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/*
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* The last byte of the i/o map must be followed by an 0xff byte.
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* We arbitrarily allocate 16 bytes here, to keep the starting
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* address on a doubleword boundary.
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*/
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offset = PAGE_SIZE - 16;
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ext->ext_tss.tss_ioopt =
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(offset - ((unsigned)&ext->ext_tss - (unsigned)ext)) << 16;
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ext->ext_iomap = (caddr_t)ext + offset;
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ext->ext_vm86.vm86_intmap = (caddr_t)ext + offset - 32;
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addr = (u_long *)ext->ext_vm86.vm86_intmap;
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for (i = 0; i < (ctob(IOPAGES) + 32 + 16) / sizeof(u_long); i++)
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*addr++ = ~0;
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ssd.ssd_base = (unsigned)&ext->ext_tss;
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ssd.ssd_limit -= ((unsigned)&ext->ext_tss - (unsigned)ext);
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ssdtosd(&ssd, &ext->ext_tssd);
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KASSERT(td == curthread, ("giving TSS to !curthread"));
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KASSERT(td->td_pcb->pcb_ext == 0, ("already have a TSS!"));
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/* Switch to the new TSS. */
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critical_enter();
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td->td_pcb->pcb_ext = ext;
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PCPU_SET(private_tss, 1);
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*PCPU_GET(tss_gdt) = ext->ext_tssd;
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ltr(GSEL(GPROC0_SEL, SEL_KPL));
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critical_exit();
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return 0;
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}
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int
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i386_set_ioperm(td, uap)
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struct thread *td;
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struct i386_ioperm_args *uap;
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{
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char *iomap;
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u_int i;
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int error;
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if ((error = priv_check(td, PRIV_IO)) != 0)
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return (error);
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if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
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return (error);
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/*
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* XXX
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* While this is restricted to root, we should probably figure out
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* whether any other driver is using this i/o address, as so not to
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* cause confusion. This probably requires a global 'usage registry'.
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*/
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if (td->td_pcb->pcb_ext == 0)
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if ((error = i386_extend_pcb(td)) != 0)
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return (error);
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iomap = (char *)td->td_pcb->pcb_ext->ext_iomap;
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if (uap->start > uap->start + uap->length ||
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uap->start + uap->length > IOPAGES * PAGE_SIZE * NBBY)
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return (EINVAL);
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for (i = uap->start; i < uap->start + uap->length; i++) {
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if (uap->enable)
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iomap[i >> 3] &= ~(1 << (i & 7));
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else
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iomap[i >> 3] |= (1 << (i & 7));
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}
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return (error);
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}
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int
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i386_get_ioperm(td, uap)
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struct thread *td;
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struct i386_ioperm_args *uap;
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{
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int i, state;
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char *iomap;
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if (uap->start >= IOPAGES * PAGE_SIZE * NBBY)
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return (EINVAL);
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if (td->td_pcb->pcb_ext == 0) {
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uap->length = 0;
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goto done;
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}
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iomap = (char *)td->td_pcb->pcb_ext->ext_iomap;
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i = uap->start;
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state = (iomap[i >> 3] >> (i & 7)) & 1;
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uap->enable = !state;
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uap->length = 1;
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for (i = uap->start + 1; i < IOPAGES * PAGE_SIZE * NBBY; i++) {
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if (state != ((iomap[i >> 3] >> (i & 7)) & 1))
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break;
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uap->length++;
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}
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done:
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return (0);
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}
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/*
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* Update the GDT entry pointing to the LDT to point to the LDT of the
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* current process. Manage dt_lock holding/unholding autonomously.
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*/
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void
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set_user_ldt(struct mdproc *mdp)
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{
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struct proc_ldt *pldt;
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int dtlocked;
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dtlocked = 0;
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if (!mtx_owned(&dt_lock)) {
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mtx_lock_spin(&dt_lock);
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dtlocked = 1;
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}
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pldt = mdp->md_ldt;
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#ifdef SMP
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gdt[PCPU_GET(cpuid) * NGDT + GUSERLDT_SEL].sd = pldt->ldt_sd;
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#else
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gdt[GUSERLDT_SEL].sd = pldt->ldt_sd;
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#endif
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lldt(GSEL(GUSERLDT_SEL, SEL_KPL));
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PCPU_SET(currentldt, GSEL(GUSERLDT_SEL, SEL_KPL));
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if (dtlocked)
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mtx_unlock_spin(&dt_lock);
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}
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#ifdef SMP
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static void
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set_user_ldt_rv(struct vmspace *vmsp)
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{
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struct thread *td;
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td = curthread;
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if (vmsp != td->td_proc->p_vmspace)
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return;
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set_user_ldt(&td->td_proc->p_md);
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}
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#endif
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/*
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* dt_lock must be held. Returns with dt_lock held.
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*/
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struct proc_ldt *
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user_ldt_alloc(struct mdproc *mdp, int len)
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{
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struct proc_ldt *pldt, *new_ldt;
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mtx_assert(&dt_lock, MA_OWNED);
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mtx_unlock_spin(&dt_lock);
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new_ldt = malloc(sizeof(struct proc_ldt),
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M_SUBPROC, M_WAITOK);
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new_ldt->ldt_len = len = NEW_MAX_LD(len);
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new_ldt->ldt_base = (caddr_t)kmem_malloc(kernel_arena,
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len * sizeof(union descriptor), M_WAITOK);
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new_ldt->ldt_refcnt = 1;
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new_ldt->ldt_active = 0;
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mtx_lock_spin(&dt_lock);
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gdt_segs[GUSERLDT_SEL].ssd_base = (unsigned)new_ldt->ldt_base;
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gdt_segs[GUSERLDT_SEL].ssd_limit = len * sizeof(union descriptor) - 1;
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ssdtosd(&gdt_segs[GUSERLDT_SEL], &new_ldt->ldt_sd);
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if ((pldt = mdp->md_ldt) != NULL) {
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if (len > pldt->ldt_len)
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len = pldt->ldt_len;
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bcopy(pldt->ldt_base, new_ldt->ldt_base,
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len * sizeof(union descriptor));
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} else
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bcopy(ldt, new_ldt->ldt_base, sizeof(ldt));
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return (new_ldt);
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}
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/*
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* Must be called with dt_lock held. Returns with dt_lock unheld.
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*/
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void
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user_ldt_free(struct thread *td)
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{
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struct mdproc *mdp = &td->td_proc->p_md;
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struct proc_ldt *pldt;
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mtx_assert(&dt_lock, MA_OWNED);
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if ((pldt = mdp->md_ldt) == NULL) {
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mtx_unlock_spin(&dt_lock);
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return;
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}
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if (td == curthread) {
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lldt(_default_ldt);
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PCPU_SET(currentldt, _default_ldt);
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}
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mdp->md_ldt = NULL;
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user_ldt_deref(pldt);
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}
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void
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user_ldt_deref(struct proc_ldt *pldt)
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{
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mtx_assert(&dt_lock, MA_OWNED);
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if (--pldt->ldt_refcnt == 0) {
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mtx_unlock_spin(&dt_lock);
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|
kmem_free(kernel_arena, (vm_offset_t)pldt->ldt_base,
|
|
pldt->ldt_len * sizeof(union descriptor));
|
|
free(pldt, M_SUBPROC);
|
|
} else
|
|
mtx_unlock_spin(&dt_lock);
|
|
}
|
|
|
|
/*
|
|
* Note for the authors of compat layers (linux, etc): copyout() in
|
|
* the function below is not a problem since it presents data in
|
|
* arch-specific format (i.e. i386-specific in this case), not in
|
|
* the OS-specific one.
|
|
*/
|
|
int
|
|
i386_get_ldt(td, uap)
|
|
struct thread *td;
|
|
struct i386_ldt_args *uap;
|
|
{
|
|
int error = 0;
|
|
struct proc_ldt *pldt;
|
|
int nldt, num;
|
|
union descriptor *lp;
|
|
|
|
#ifdef DEBUG
|
|
printf("i386_get_ldt: start=%d num=%d descs=%p\n",
|
|
uap->start, uap->num, (void *)uap->descs);
|
|
#endif
|
|
|
|
mtx_lock_spin(&dt_lock);
|
|
if ((pldt = td->td_proc->p_md.md_ldt) != NULL) {
|
|
nldt = pldt->ldt_len;
|
|
lp = &((union descriptor *)(pldt->ldt_base))[uap->start];
|
|
mtx_unlock_spin(&dt_lock);
|
|
num = min(uap->num, nldt);
|
|
} else {
|
|
mtx_unlock_spin(&dt_lock);
|
|
nldt = sizeof(ldt)/sizeof(ldt[0]);
|
|
num = min(uap->num, nldt);
|
|
lp = &ldt[uap->start];
|
|
}
|
|
|
|
if ((uap->start > (unsigned int)nldt) ||
|
|
((unsigned int)num > (unsigned int)nldt) ||
|
|
((unsigned int)(uap->start + num) > (unsigned int)nldt))
|
|
return(EINVAL);
|
|
|
|
error = copyout(lp, uap->descs, num * sizeof(union descriptor));
|
|
if (!error)
|
|
td->td_retval[0] = num;
|
|
|
|
return(error);
|
|
}
|
|
|
|
int
|
|
i386_set_ldt(td, uap, descs)
|
|
struct thread *td;
|
|
struct i386_ldt_args *uap;
|
|
union descriptor *descs;
|
|
{
|
|
int error = 0, i;
|
|
int largest_ld;
|
|
struct mdproc *mdp = &td->td_proc->p_md;
|
|
struct proc_ldt *pldt;
|
|
union descriptor *dp;
|
|
|
|
#ifdef DEBUG
|
|
printf("i386_set_ldt: start=%d num=%d descs=%p\n",
|
|
uap->start, uap->num, (void *)uap->descs);
|
|
#endif
|
|
|
|
if (descs == NULL) {
|
|
/* Free descriptors */
|
|
if (uap->start == 0 && uap->num == 0) {
|
|
/*
|
|
* Treat this as a special case, so userland needn't
|
|
* know magic number NLDT.
|
|
*/
|
|
uap->start = NLDT;
|
|
uap->num = MAX_LD - NLDT;
|
|
}
|
|
if (uap->num == 0)
|
|
return (EINVAL);
|
|
mtx_lock_spin(&dt_lock);
|
|
if ((pldt = mdp->md_ldt) == NULL ||
|
|
uap->start >= pldt->ldt_len) {
|
|
mtx_unlock_spin(&dt_lock);
|
|
return (0);
|
|
}
|
|
largest_ld = uap->start + uap->num;
|
|
if (largest_ld > pldt->ldt_len)
|
|
largest_ld = pldt->ldt_len;
|
|
i = largest_ld - uap->start;
|
|
bzero(&((union descriptor *)(pldt->ldt_base))[uap->start],
|
|
sizeof(union descriptor) * i);
|
|
mtx_unlock_spin(&dt_lock);
|
|
return (0);
|
|
}
|
|
|
|
if (!(uap->start == LDT_AUTO_ALLOC && uap->num == 1)) {
|
|
/* verify range of descriptors to modify */
|
|
largest_ld = uap->start + uap->num;
|
|
if (uap->start >= MAX_LD || largest_ld > MAX_LD) {
|
|
return (EINVAL);
|
|
}
|
|
}
|
|
|
|
/* Check descriptors for access violations */
|
|
for (i = 0; i < uap->num; i++) {
|
|
dp = &descs[i];
|
|
|
|
switch (dp->sd.sd_type) {
|
|
case SDT_SYSNULL: /* system null */
|
|
dp->sd.sd_p = 0;
|
|
break;
|
|
case SDT_SYS286TSS: /* system 286 TSS available */
|
|
case SDT_SYSLDT: /* system local descriptor table */
|
|
case SDT_SYS286BSY: /* system 286 TSS busy */
|
|
case SDT_SYSTASKGT: /* system task gate */
|
|
case SDT_SYS286IGT: /* system 286 interrupt gate */
|
|
case SDT_SYS286TGT: /* system 286 trap gate */
|
|
case SDT_SYSNULL2: /* undefined by Intel */
|
|
case SDT_SYS386TSS: /* system 386 TSS available */
|
|
case SDT_SYSNULL3: /* undefined by Intel */
|
|
case SDT_SYS386BSY: /* system 386 TSS busy */
|
|
case SDT_SYSNULL4: /* undefined by Intel */
|
|
case SDT_SYS386IGT: /* system 386 interrupt gate */
|
|
case SDT_SYS386TGT: /* system 386 trap gate */
|
|
case SDT_SYS286CGT: /* system 286 call gate */
|
|
case SDT_SYS386CGT: /* system 386 call gate */
|
|
/* I can't think of any reason to allow a user proc
|
|
* to create a segment of these types. They are
|
|
* for OS use only.
|
|
*/
|
|
return (EACCES);
|
|
/*NOTREACHED*/
|
|
|
|
/* memory segment types */
|
|
case SDT_MEMEC: /* memory execute only conforming */
|
|
case SDT_MEMEAC: /* memory execute only accessed conforming */
|
|
case SDT_MEMERC: /* memory execute read conforming */
|
|
case SDT_MEMERAC: /* memory execute read accessed conforming */
|
|
/* Must be "present" if executable and conforming. */
|
|
if (dp->sd.sd_p == 0)
|
|
return (EACCES);
|
|
break;
|
|
case SDT_MEMRO: /* memory read only */
|
|
case SDT_MEMROA: /* memory read only accessed */
|
|
case SDT_MEMRW: /* memory read write */
|
|
case SDT_MEMRWA: /* memory read write accessed */
|
|
case SDT_MEMROD: /* memory read only expand dwn limit */
|
|
case SDT_MEMRODA: /* memory read only expand dwn lim accessed */
|
|
case SDT_MEMRWD: /* memory read write expand dwn limit */
|
|
case SDT_MEMRWDA: /* memory read write expand dwn lim acessed */
|
|
case SDT_MEME: /* memory execute only */
|
|
case SDT_MEMEA: /* memory execute only accessed */
|
|
case SDT_MEMER: /* memory execute read */
|
|
case SDT_MEMERA: /* memory execute read accessed */
|
|
break;
|
|
default:
|
|
return(EINVAL);
|
|
/*NOTREACHED*/
|
|
}
|
|
|
|
/* Only user (ring-3) descriptors may be present. */
|
|
if ((dp->sd.sd_p != 0) && (dp->sd.sd_dpl != SEL_UPL))
|
|
return (EACCES);
|
|
}
|
|
|
|
if (uap->start == LDT_AUTO_ALLOC && uap->num == 1) {
|
|
/* Allocate a free slot */
|
|
mtx_lock_spin(&dt_lock);
|
|
if ((pldt = mdp->md_ldt) == NULL) {
|
|
if ((error = i386_ldt_grow(td, NLDT + 1))) {
|
|
mtx_unlock_spin(&dt_lock);
|
|
return (error);
|
|
}
|
|
pldt = mdp->md_ldt;
|
|
}
|
|
again:
|
|
/*
|
|
* start scanning a bit up to leave room for NVidia and
|
|
* Wine, which still user the "Blat" method of allocation.
|
|
*/
|
|
dp = &((union descriptor *)(pldt->ldt_base))[NLDT];
|
|
for (i = NLDT; i < pldt->ldt_len; ++i) {
|
|
if (dp->sd.sd_type == SDT_SYSNULL)
|
|
break;
|
|
dp++;
|
|
}
|
|
if (i >= pldt->ldt_len) {
|
|
if ((error = i386_ldt_grow(td, pldt->ldt_len+1))) {
|
|
mtx_unlock_spin(&dt_lock);
|
|
return (error);
|
|
}
|
|
goto again;
|
|
}
|
|
uap->start = i;
|
|
error = i386_set_ldt_data(td, i, 1, descs);
|
|
mtx_unlock_spin(&dt_lock);
|
|
} else {
|
|
largest_ld = uap->start + uap->num;
|
|
mtx_lock_spin(&dt_lock);
|
|
if (!(error = i386_ldt_grow(td, largest_ld))) {
|
|
error = i386_set_ldt_data(td, uap->start, uap->num,
|
|
descs);
|
|
}
|
|
mtx_unlock_spin(&dt_lock);
|
|
}
|
|
if (error == 0)
|
|
td->td_retval[0] = uap->start;
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
i386_set_ldt_data(struct thread *td, int start, int num,
|
|
union descriptor *descs)
|
|
{
|
|
struct mdproc *mdp = &td->td_proc->p_md;
|
|
struct proc_ldt *pldt = mdp->md_ldt;
|
|
|
|
mtx_assert(&dt_lock, MA_OWNED);
|
|
|
|
/* Fill in range */
|
|
bcopy(descs,
|
|
&((union descriptor *)(pldt->ldt_base))[start],
|
|
num * sizeof(union descriptor));
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
i386_ldt_grow(struct thread *td, int len)
|
|
{
|
|
struct mdproc *mdp = &td->td_proc->p_md;
|
|
struct proc_ldt *new_ldt, *pldt;
|
|
caddr_t old_ldt_base = NULL_LDT_BASE;
|
|
int old_ldt_len = 0;
|
|
|
|
mtx_assert(&dt_lock, MA_OWNED);
|
|
|
|
if (len > MAX_LD)
|
|
return (ENOMEM);
|
|
if (len < NLDT + 1)
|
|
len = NLDT + 1;
|
|
|
|
/* Allocate a user ldt. */
|
|
if ((pldt = mdp->md_ldt) == NULL || len > pldt->ldt_len) {
|
|
new_ldt = user_ldt_alloc(mdp, len);
|
|
if (new_ldt == NULL)
|
|
return (ENOMEM);
|
|
pldt = mdp->md_ldt;
|
|
|
|
if (pldt != NULL) {
|
|
if (new_ldt->ldt_len <= pldt->ldt_len) {
|
|
/*
|
|
* We just lost the race for allocation, so
|
|
* free the new object and return.
|
|
*/
|
|
mtx_unlock_spin(&dt_lock);
|
|
kmem_free(kernel_arena,
|
|
(vm_offset_t)new_ldt->ldt_base,
|
|
new_ldt->ldt_len * sizeof(union descriptor));
|
|
free(new_ldt, M_SUBPROC);
|
|
mtx_lock_spin(&dt_lock);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* We have to substitute the current LDT entry for
|
|
* curproc with the new one since its size grew.
|
|
*/
|
|
old_ldt_base = pldt->ldt_base;
|
|
old_ldt_len = pldt->ldt_len;
|
|
pldt->ldt_sd = new_ldt->ldt_sd;
|
|
pldt->ldt_base = new_ldt->ldt_base;
|
|
pldt->ldt_len = new_ldt->ldt_len;
|
|
} else
|
|
mdp->md_ldt = pldt = new_ldt;
|
|
#ifdef SMP
|
|
/*
|
|
* Signal other cpus to reload ldt. We need to unlock dt_lock
|
|
* here because other CPU will contest on it since their
|
|
* curthreads won't hold the lock and will block when trying
|
|
* to acquire it.
|
|
*/
|
|
mtx_unlock_spin(&dt_lock);
|
|
smp_rendezvous(NULL, (void (*)(void *))set_user_ldt_rv,
|
|
NULL, td->td_proc->p_vmspace);
|
|
#else
|
|
set_user_ldt(&td->td_proc->p_md);
|
|
mtx_unlock_spin(&dt_lock);
|
|
#endif
|
|
if (old_ldt_base != NULL_LDT_BASE) {
|
|
kmem_free(kernel_arena, (vm_offset_t)old_ldt_base,
|
|
old_ldt_len * sizeof(union descriptor));
|
|
free(new_ldt, M_SUBPROC);
|
|
}
|
|
mtx_lock_spin(&dt_lock);
|
|
}
|
|
return (0);
|
|
}
|