4cc6942f37
setting call gate, which must be 64 bit, put a code segment descriptor into ldt slot 0. This way, syscall shim does not switch temporary to 64bit trampoline, and does not create a window where signal delivery interrupts 64 bit mode (signal handler cannot return). The cost is shim running with non-zero based segment in %cs, which requires vfork() handling make more assumptions. Sponsored by: The FreeBSD Foundation MFC after: 1 week
251 lines
6.4 KiB
C
251 lines
6.4 KiB
C
/*-
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* Copyright (C) 1994, David Greenman
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the University of Utah, and William Jolitz.
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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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* 386 Trap and System call handling
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*/
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#include "opt_clock.h"
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#include "opt_compat.h"
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#include "opt_cpu.h"
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#include "opt_isa.h"
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/pioctl.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/ptrace.h>
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#include <sys/resourcevar.h>
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#include <sys/signalvar.h>
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#include <sys/syscall.h>
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#include <sys/sysctl.h>
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#include <sys/sysent.h>
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#include <sys/uio.h>
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#include <sys/vmmeter.h>
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#include <security/audit/audit.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_map.h>
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#include <vm/vm_page.h>
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#include <vm/vm_extern.h>
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#include <machine/cpu.h>
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#include <machine/intr_machdep.h>
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#include <machine/md_var.h>
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#include <compat/freebsd32/freebsd32_signal.h>
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#include <compat/freebsd32/freebsd32_util.h>
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#include <compat/ia32/ia32_signal.h>
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#include <machine/psl.h>
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#include <machine/segments.h>
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#include <machine/specialreg.h>
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#include <machine/sysarch.h>
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#include <machine/frame.h>
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#include <machine/md_var.h>
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#include <machine/pcb.h>
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#include <machine/cpufunc.h>
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#define IDTVEC(name) __CONCAT(X,name)
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extern inthand_t IDTVEC(int0x80_syscall), IDTVEC(rsvd);
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void ia32_syscall(struct trapframe *frame); /* Called from asm code */
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void
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ia32_set_syscall_retval(struct thread *td, int error)
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{
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cpu_set_syscall_retval(td, error);
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}
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int
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ia32_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
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{
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struct proc *p;
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struct trapframe *frame;
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caddr_t params;
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u_int32_t args[8], tmp;
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int error, i;
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p = td->td_proc;
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frame = td->td_frame;
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params = (caddr_t)frame->tf_rsp + sizeof(u_int32_t);
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sa->code = frame->tf_rax;
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/*
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* Need to check if this is a 32 bit or 64 bit syscall.
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*/
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if (sa->code == SYS_syscall) {
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/*
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* Code is first argument, followed by actual args.
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*/
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error = fueword32(params, &tmp);
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if (error == -1)
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return (EFAULT);
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sa->code = tmp;
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params += sizeof(int);
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} else if (sa->code == SYS___syscall) {
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/*
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* Like syscall, but code is a quad, so as to maintain
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* quad alignment for the rest of the arguments.
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* We use a 32-bit fetch in case params is not
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* aligned.
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*/
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error = fueword32(params, &tmp);
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if (error == -1)
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return (EFAULT);
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sa->code = tmp;
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params += sizeof(quad_t);
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}
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if (p->p_sysent->sv_mask)
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sa->code &= p->p_sysent->sv_mask;
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if (sa->code >= p->p_sysent->sv_size)
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sa->callp = &p->p_sysent->sv_table[0];
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else
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sa->callp = &p->p_sysent->sv_table[sa->code];
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sa->narg = sa->callp->sy_narg;
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if (params != NULL && sa->narg != 0)
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error = copyin(params, (caddr_t)args,
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(u_int)(sa->narg * sizeof(int)));
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else
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error = 0;
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for (i = 0; i < sa->narg; i++)
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sa->args[i] = args[i];
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if (error == 0) {
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td->td_retval[0] = 0;
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td->td_retval[1] = frame->tf_rdx;
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}
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return (error);
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}
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#include "../../kern/subr_syscall.c"
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void
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ia32_syscall(struct trapframe *frame)
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{
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struct thread *td;
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struct syscall_args sa;
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register_t orig_tf_rflags;
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int error;
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ksiginfo_t ksi;
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orig_tf_rflags = frame->tf_rflags;
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td = curthread;
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td->td_frame = frame;
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error = syscallenter(td, &sa);
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/*
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* Traced syscall.
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*/
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if (orig_tf_rflags & PSL_T) {
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frame->tf_rflags &= ~PSL_T;
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ksiginfo_init_trap(&ksi);
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ksi.ksi_signo = SIGTRAP;
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ksi.ksi_code = TRAP_TRACE;
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ksi.ksi_addr = (void *)frame->tf_rip;
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trapsignal(td, &ksi);
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}
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syscallret(td, error, &sa);
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}
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static void
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ia32_syscall_enable(void *dummy)
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{
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setidt(IDT_SYSCALL, &IDTVEC(int0x80_syscall), SDT_SYSIGT, SEL_UPL, 0);
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}
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static void
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ia32_syscall_disable(void *dummy)
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{
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setidt(IDT_SYSCALL, &IDTVEC(rsvd), SDT_SYSIGT, SEL_KPL, 0);
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}
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SYSINIT(ia32_syscall, SI_SUB_EXEC, SI_ORDER_ANY, ia32_syscall_enable, NULL);
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SYSUNINIT(ia32_syscall, SI_SUB_EXEC, SI_ORDER_ANY, ia32_syscall_disable, NULL);
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#ifdef COMPAT_43
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int
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setup_lcall_gate(void)
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{
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struct i386_ldt_args uap;
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struct user_segment_descriptor desc;
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uint32_t lcall_addr;
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int error;
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bzero(&uap, sizeof(uap));
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uap.start = 0;
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uap.num = 1;
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lcall_addr = curproc->p_sysent->sv_psstrings - sz_lcall_tramp;
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bzero(&desc, sizeof(desc));
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desc.sd_type = SDT_MEMERA;
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desc.sd_dpl = SEL_UPL;
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desc.sd_p = 1;
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desc.sd_def32 = 1;
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desc.sd_gran = 1;
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desc.sd_lolimit = 0xffff;
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desc.sd_hilimit = 0xf;
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desc.sd_lobase = lcall_addr;
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desc.sd_hibase = lcall_addr >> 24;
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error = amd64_set_ldt(curthread, &uap, &desc);
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if (error != 0)
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return (error);
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return (0);
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}
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#endif
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