/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 2018 The FreeBSD Foundation
* Copyright (c) 1992 Terrence R. Lambert.
* Copyright (c) 1982, 1987, 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* Portions of this software were developed by A. Joseph Koshy under
* sponsorship from the FreeBSD Foundation and Google, Inc.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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: @(#)machdep.c 7.4 (Berkeley) 6/3/91
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_cpu.h"
#include "opt_ddb.h"
#include "opt_kstack_pages.h"
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/ptrace.h>
#include <sys/reg.h>
#include <sys/rwlock.h>
#include <sys/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/ucontext.h>
#include <sys/vmmeter.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#ifdef DDB
#ifndef KDB
#error KDB must be enabled in order for DDB to work!
#endif
#include <ddb/ddb.h>
#include <ddb/db_sym.h>
#endif
#include <machine/cpu.h>
#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/pcb_ext.h>
#include <machine/proc.h>
#include <machine/sigframe.h>
#include <machine/specialreg.h>
#include <machine/sysarch.h>
#include <machine/trap.h>
static void fpstate_drop(struct thread *td);
static void get_fpcontext(struct thread *td, mcontext_t *mcp,
char *xfpusave, size_t xfpusave_len);
static int set_fpcontext(struct thread *td, mcontext_t *mcp,
char *xfpustate, size_t xfpustate_len);
#ifdef COMPAT_43
static void osendsig(sig_t catcher, ksiginfo_t *, sigset_t *mask);
#endif
#ifdef COMPAT_FREEBSD4
static void freebsd4_sendsig(sig_t catcher, ksiginfo_t *, sigset_t *mask);
#endif
extern struct sysentvec elf32_freebsd_sysvec;
_Static_assert(sizeof(mcontext_t) == 640, "mcontext_t size incorrect");
_Static_assert(sizeof(ucontext_t) == 704, "ucontext_t size incorrect");
_Static_assert(sizeof(siginfo_t) == 64, "siginfo_t size incorrect");
/*
* Send an interrupt to process.
*
* Stack is set up to allow sigcode stored at top to call routine,
* followed by call to sigreturn routine below. After sigreturn
* resets the signal mask, the stack, and the frame pointer, it
* returns to the user specified pc, psl.
*/
#ifdef COMPAT_43
static void
osendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
struct osigframe sf, *fp;
struct proc *p;
struct thread *td;
struct sigacts *psp;
struct trapframe *regs;
int sig;
int oonstack;
td = curthread;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
sig = ksi->ksi_signo;
psp = p->p_sigacts;
mtx_assert(&psp->ps_mtx, MA_OWNED);
regs = td->td_frame;
oonstack = sigonstack(regs->tf_esp);
/* Allocate space for the signal handler context. */
if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
fp = (struct osigframe *)((uintptr_t)td->td_sigstk.ss_sp +
td->td_sigstk.ss_size - sizeof(struct osigframe));
#if defined(COMPAT_43)
td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
} else
fp = (struct osigframe *)regs->tf_esp - 1;
/* Build the argument list for the signal handler. */
sf.sf_signum = sig;
sf.sf_scp = (register_t)&fp->sf_siginfo.si_sc;
bzero(&sf.sf_siginfo, sizeof(sf.sf_siginfo));
if (SIGISMEMBER(psp->ps_siginfo, sig)) {
/* Signal handler installed with SA_SIGINFO. */
sf.sf_arg2 = (register_t)&fp->sf_siginfo;
sf.sf_siginfo.si_signo = sig;
sf.sf_siginfo.si_code = ksi->ksi_code;
sf.sf_ahu.sf_action = (__osiginfohandler_t *)catcher;
sf.sf_addr = 0;
} else {
/* Old FreeBSD-style arguments. */
sf.sf_arg2 = ksi->ksi_code;
sf.sf_addr = (register_t)ksi->ksi_addr;
sf.sf_ahu.sf_handler = catcher;
}
mtx_unlock(&psp->ps_mtx);
PROC_UNLOCK(p);
/* Save most if not all of trap frame. */
sf.sf_siginfo.si_sc.sc_eax = regs->tf_eax;
sf.sf_siginfo.si_sc.sc_ebx = regs->tf_ebx;
sf.sf_siginfo.si_sc.sc_ecx = regs->tf_ecx;
sf.sf_siginfo.si_sc.sc_edx = regs->tf_edx;
sf.sf_siginfo.si_sc.sc_esi = regs->tf_esi;
sf.sf_siginfo.si_sc.sc_edi = regs->tf_edi;
sf.sf_siginfo.si_sc.sc_cs = regs->tf_cs;
sf.sf_siginfo.si_sc.sc_ds = regs->tf_ds;
sf.sf_siginfo.si_sc.sc_ss = regs->tf_ss;
sf.sf_siginfo.si_sc.sc_es = regs->tf_es;
sf.sf_siginfo.si_sc.sc_fs = regs->tf_fs;
sf.sf_siginfo.si_sc.sc_gs = rgs();
sf.sf_siginfo.si_sc.sc_isp = regs->tf_isp;
/* Build the signal context to be used by osigreturn(). */
sf.sf_siginfo.si_sc.sc_onstack = (oonstack) ? 1 : 0;
SIG2OSIG(*mask, sf.sf_siginfo.si_sc.sc_mask);
sf.sf_siginfo.si_sc.sc_sp = regs->tf_esp;
sf.sf_siginfo.si_sc.sc_fp = regs->tf_ebp;
sf.sf_siginfo.si_sc.sc_pc = regs->tf_eip;
sf.sf_siginfo.si_sc.sc_ps = regs->tf_eflags;
sf.sf_siginfo.si_sc.sc_trapno = regs->tf_trapno;
sf.sf_siginfo.si_sc.sc_err = regs->tf_err;
/*
* If we're a vm86 process, we want to save the segment registers.
* We also change eflags to be our emulated eflags, not the actual
* eflags.
*/
if (regs->tf_eflags & PSL_VM) {
/* XXX confusing names: `tf' isn't a trapframe; `regs' is. */
struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86;
sf.sf_siginfo.si_sc.sc_gs = tf->tf_vm86_gs;
sf.sf_siginfo.si_sc.sc_fs = tf->tf_vm86_fs;
sf.sf_siginfo.si_sc.sc_es = tf->tf_vm86_es;
sf.sf_siginfo.si_sc.sc_ds = tf->tf_vm86_ds;
if (vm86->vm86_has_vme == 0)
sf.sf_siginfo.si_sc.sc_ps =
(tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
(vm86->vm86_eflags & (PSL_VIF | PSL_VIP));
/* See sendsig() for comments. */
tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
}
/*
* Copy the sigframe out to the user's stack.
*/
if (copyout(&sf, fp, sizeof(*fp)) != 0) {
PROC_LOCK(p);
sigexit(td, SIGILL);
}
regs->tf_esp = (int)fp;
if (PROC_HAS_SHP(p)) {
regs->tf_eip = PROC_SIGCODE(p) + szsigcode -
szosigcode;
} else {
/* a.out sysentvec does not use shared page */
regs->tf_eip = PROC_PS_STRINGS(p) - szosigcode;
}
regs->tf_eflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _udatasel;
load_gs(_udatasel);
regs->tf_ss = _udatasel;
PROC_LOCK(p);
mtx_lock(&psp->ps_mtx);
}
#endif /* COMPAT_43 */
#ifdef COMPAT_FREEBSD4
static void
freebsd4_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
struct freebsd4_sigframe sf, *sfp;
struct proc *p;
struct thread *td;
struct sigacts *psp;
struct trapframe *regs;
int sig;
int oonstack;
td = curthread;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
sig = ksi->ksi_signo;
psp = p->p_sigacts;
mtx_assert(&psp->ps_mtx, MA_OWNED);
regs = td->td_frame;
oonstack = sigonstack(regs->tf_esp);
/* Save user context. */
bzero(&sf, sizeof(sf));
sf.sf_uc.uc_sigmask = *mask;
sf.sf_uc.uc_stack = td->td_sigstk;
sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
sf.sf_uc.uc_mcontext.mc_gs = rgs();
bcopy(regs, &sf.sf_uc.uc_mcontext.mc_fs, sizeof(*regs));
bzero(sf.sf_uc.uc_mcontext.mc_fpregs,
sizeof(sf.sf_uc.uc_mcontext.mc_fpregs));
bzero(sf.sf_uc.uc_mcontext.__spare__,
sizeof(sf.sf_uc.uc_mcontext.__spare__));
bzero(sf.sf_uc.__spare__, sizeof(sf.sf_uc.__spare__));
/* Allocate space for the signal handler context. */
if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
sfp = (struct freebsd4_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
td->td_sigstk.ss_size - sizeof(struct freebsd4_sigframe));
#if defined(COMPAT_43)
td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
} else
sfp = (struct freebsd4_sigframe *)regs->tf_esp - 1;
/* Build the argument list for the signal handler. */
sf.sf_signum = sig;
sf.sf_ucontext = (register_t)&sfp->sf_uc;
bzero(&sf.sf_si, sizeof(sf.sf_si));
if (SIGISMEMBER(psp->ps_siginfo, sig)) {
/* Signal handler installed with SA_SIGINFO. */
sf.sf_siginfo = (register_t)&sfp->sf_si;
sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher;
/* Fill in POSIX parts */
sf.sf_si.si_signo = sig;
sf.sf_si.si_code = ksi->ksi_code;
sf.sf_si.si_addr = ksi->ksi_addr;
} else {
/* Old FreeBSD-style arguments. */
sf.sf_siginfo = ksi->ksi_code;
sf.sf_addr = (register_t)ksi->ksi_addr;
sf.sf_ahu.sf_handler = catcher;
}
mtx_unlock(&psp->ps_mtx);
PROC_UNLOCK(p);
/*
* If we're a vm86 process, we want to save the segment registers.
* We also change eflags to be our emulated eflags, not the actual
* eflags.
*/
if (regs->tf_eflags & PSL_VM) {
struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86;
sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs;
sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs;
sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es;
sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds;
if (vm86->vm86_has_vme == 0)
sf.sf_uc.uc_mcontext.mc_eflags =
(tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
(vm86->vm86_eflags & (PSL_VIF | PSL_VIP));
/*
* Clear PSL_NT to inhibit T_TSSFLT faults on return from
* syscalls made by the signal handler. This just avoids
* wasting time for our lazy fixup of such faults. PSL_NT
* does nothing in vm86 mode, but vm86 programs can set it
* almost legitimately in probes for old cpu types.
*/
tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
}
/*
* Copy the sigframe out to the user's stack.
*/
if (copyout(&sf, sfp, sizeof(*sfp)) != 0) {
PROC_LOCK(p);
sigexit(td, SIGILL);
}
regs->tf_esp = (int)sfp;
regs->tf_eip = PROC_SIGCODE(p) + szsigcode -
szfreebsd4_sigcode;
regs->tf_eflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _udatasel;
regs->tf_ss = _udatasel;
PROC_LOCK(p);
mtx_lock(&psp->ps_mtx);
}
#endif /* COMPAT_FREEBSD4 */
void
sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
struct sigframe sf, *sfp;
struct proc *p;
struct thread *td;
struct sigacts *psp;
char *sp;
struct trapframe *regs;
struct segment_descriptor *sdp;
char *xfpusave;
size_t xfpusave_len;
int sig;
int oonstack;
td = curthread;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
sig = ksi->ksi_signo;
psp = p->p_sigacts;
mtx_assert(&psp->ps_mtx, MA_OWNED);
#ifdef COMPAT_FREEBSD4
if (SIGISMEMBER(psp->ps_freebsd4, sig)) {
freebsd4_sendsig(catcher, ksi, mask);
return;
}
#endif
#ifdef COMPAT_43
if (SIGISMEMBER(psp->ps_osigset, sig)) {
osendsig(catcher, ksi, mask);
return;
}
#endif
regs = td->td_frame;
oonstack = sigonstack(regs->tf_esp);
if (cpu_max_ext_state_size > sizeof(union savefpu) && use_xsave) {
xfpusave_len = cpu_max_ext_state_size - sizeof(union savefpu);
xfpusave = __builtin_alloca(xfpusave_len);
} else {
xfpusave_len = 0;
xfpusave = NULL;
}
/* Save user context. */
bzero(&sf, sizeof(sf));
sf.sf_uc.uc_sigmask = *mask;
sf.sf_uc.uc_stack = td->td_sigstk;
sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
sf.sf_uc.uc_mcontext.mc_gs = rgs();
bcopy(regs, &sf.sf_uc.uc_mcontext.mc_fs, sizeof(*regs));
sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */
get_fpcontext(td, &sf.sf_uc.uc_mcontext, xfpusave, xfpusave_len);
fpstate_drop(td);
/*
* Unconditionally fill the fsbase and gsbase into the mcontext.
*/
sdp = &td->td_pcb->pcb_fsd;
sf.sf_uc.uc_mcontext.mc_fsbase = sdp->sd_hibase << 24 |
sdp->sd_lobase;
sdp = &td->td_pcb->pcb_gsd;
sf.sf_uc.uc_mcontext.mc_gsbase = sdp->sd_hibase << 24 |
sdp->sd_lobase;
bzero(sf.sf_uc.uc_mcontext.mc_spare2,
sizeof(sf.sf_uc.uc_mcontext.mc_spare2));
/* Allocate space for the signal handler context. */
if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
sp = (char *)td->td_sigstk.ss_sp + td->td_sigstk.ss_size;
#if defined(COMPAT_43)
td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
} else
sp = (char *)regs->tf_esp - 128;
if (xfpusave != NULL) {
sp -= xfpusave_len;
sp = (char *)((unsigned int)sp & ~0x3F);
sf.sf_uc.uc_mcontext.mc_xfpustate = (register_t)sp;
}
sp -= sizeof(struct sigframe);
/* Align to 16 bytes. */
sfp = (struct sigframe *)((unsigned int)sp & ~0xF);
/* Build the argument list for the signal handler. */
sf.sf_signum = sig;
sf.sf_ucontext = (register_t)&sfp->sf_uc;
bzero(&sf.sf_si, sizeof(sf.sf_si));
if (SIGISMEMBER(psp->ps_siginfo, sig)) {
/* Signal handler installed with SA_SIGINFO. */
sf.sf_siginfo = (register_t)&sfp->sf_si;
sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher;
/* Fill in POSIX parts */
sf.sf_si = ksi->ksi_info;
sf.sf_si.si_signo = sig; /* maybe a translated signal */
} else {
/* Old FreeBSD-style arguments. */
sf.sf_siginfo = ksi->ksi_code;
sf.sf_addr = (register_t)ksi->ksi_addr;
sf.sf_ahu.sf_handler = catcher;
}
mtx_unlock(&psp->ps_mtx);
PROC_UNLOCK(p);
/*
* If we're a vm86 process, we want to save the segment registers.
* We also change eflags to be our emulated eflags, not the actual
* eflags.
*/
if (regs->tf_eflags & PSL_VM) {
struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86;
sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs;
sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs;
sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es;
sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds;
if (vm86->vm86_has_vme == 0)
sf.sf_uc.uc_mcontext.mc_eflags =
(tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
(vm86->vm86_eflags & (PSL_VIF | PSL_VIP));
/*
* Clear PSL_NT to inhibit T_TSSFLT faults on return from
* syscalls made by the signal handler. This just avoids
* wasting time for our lazy fixup of such faults. PSL_NT
* does nothing in vm86 mode, but vm86 programs can set it
* almost legitimately in probes for old cpu types.
*/
tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
}
/*
* Copy the sigframe out to the user's stack.
*/
if (copyout(&sf, sfp, sizeof(*sfp)) != 0 ||
(xfpusave != NULL && copyout(xfpusave,
(void *)sf.sf_uc.uc_mcontext.mc_xfpustate, xfpusave_len)
!= 0)) {
PROC_LOCK(p);
sigexit(td, SIGILL);
}
regs->tf_esp = (int)sfp;
regs->tf_eip = PROC_SIGCODE(p);
if (regs->tf_eip == 0)
regs->tf_eip = PROC_PS_STRINGS(p) - szsigcode;
regs->tf_eflags &= ~(PSL_T | PSL_D);
regs->tf_cs = _ucodesel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _udatasel;
regs->tf_ss = _udatasel;
PROC_LOCK(p);
mtx_lock(&psp->ps_mtx);
}
/*
* System call to cleanup state after a signal has been taken. Reset
* signal mask and stack state from context left by sendsig (above).
* Return to previous pc and psl as specified by context left by
* sendsig. Check carefully to make sure that the user has not
* modified the state to gain improper privileges.
*/
#ifdef COMPAT_43
int
osigreturn(struct thread *td, struct osigreturn_args *uap)
{
struct osigcontext sc;
struct trapframe *regs;
struct osigcontext *scp;
int eflags, error;
ksiginfo_t ksi;
regs = td->td_frame;
error = copyin(uap->sigcntxp, &sc, sizeof(sc));
if (error != 0)
return (error);
scp = ≻
eflags = scp->sc_ps;
if (eflags & PSL_VM) {
struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
struct vm86_kernel *vm86;
/*
* if pcb_ext == 0 or vm86_inited == 0, the user hasn't
* set up the vm86 area, and we can't enter vm86 mode.
*/
if (td->td_pcb->pcb_ext == 0)
return (EINVAL);
vm86 = &td->td_pcb->pcb_ext->ext_vm86;
if (vm86->vm86_inited == 0)
return (EINVAL);
/* Go back to user mode if both flags are set. */
if ((eflags & PSL_VIP) && (eflags & PSL_VIF)) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_addr = (void *)regs->tf_eip;
trapsignal(td, &ksi);
}
if (vm86->vm86_has_vme) {
eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
(eflags & VME_USERCHANGE) | PSL_VM;
} else {
vm86->vm86_eflags = eflags; /* save VIF, VIP */
eflags = (tf->tf_eflags & ~VM_USERCHANGE) |
(eflags & VM_USERCHANGE) | PSL_VM;
}
tf->tf_vm86_ds = scp->sc_ds;
tf->tf_vm86_es = scp->sc_es;
tf->tf_vm86_fs = scp->sc_fs;
tf->tf_vm86_gs = scp->sc_gs;
tf->tf_ds = _udatasel;
tf->tf_es = _udatasel;
tf->tf_fs = _udatasel;
} else {
/*
* Don't allow users to change privileged or reserved flags.
*/
if (!EFL_SECURE(eflags, regs->tf_eflags)) {
return (EINVAL);
}
/*
* Don't allow users to load a valid privileged %cs. Let the
* hardware check for invalid selectors, excess privilege in
* other selectors, invalid %eip's and invalid %esp's.
*/
if (!CS_SECURE(scp->sc_cs)) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_trapno = T_PROTFLT;
ksi.ksi_addr = (void *)regs->tf_eip;
trapsignal(td, &ksi);
return (EINVAL);
}
regs->tf_ds = scp->sc_ds;
regs->tf_es = scp->sc_es;
regs->tf_fs = scp->sc_fs;
}
/* Restore remaining registers. */
regs->tf_eax = scp->sc_eax;
regs->tf_ebx = scp->sc_ebx;
regs->tf_ecx = scp->sc_ecx;
regs->tf_edx = scp->sc_edx;
regs->tf_esi = scp->sc_esi;
regs->tf_edi = scp->sc_edi;
regs->tf_cs = scp->sc_cs;
regs->tf_ss = scp->sc_ss;
regs->tf_isp = scp->sc_isp;
regs->tf_ebp = scp->sc_fp;
regs->tf_esp = scp->sc_sp;
regs->tf_eip = scp->sc_pc;
regs->tf_eflags = eflags;
#if defined(COMPAT_43)
if (scp->sc_onstack & 1)
td->td_sigstk.ss_flags |= SS_ONSTACK;
else
td->td_sigstk.ss_flags &= ~SS_ONSTACK;
#endif
kern_sigprocmask(td, SIG_SETMASK, (sigset_t *)&scp->sc_mask, NULL,
SIGPROCMASK_OLD);
return (EJUSTRETURN);
}
#endif /* COMPAT_43 */
#ifdef COMPAT_FREEBSD4
int
freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
{
struct freebsd4_ucontext uc;
struct trapframe *regs;
struct freebsd4_ucontext *ucp;
int cs, eflags, error;
ksiginfo_t ksi;
error = copyin(uap->sigcntxp, &uc, sizeof(uc));
if (error != 0)
return (error);
ucp = &uc;
regs = td->td_frame;
eflags = ucp->uc_mcontext.mc_eflags;
if (eflags & PSL_VM) {
struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
struct vm86_kernel *vm86;
/*
* if pcb_ext == 0 or vm86_inited == 0, the user hasn't
* set up the vm86 area, and we can't enter vm86 mode.
*/
if (td->td_pcb->pcb_ext == 0)
return (EINVAL);
vm86 = &td->td_pcb->pcb_ext->ext_vm86;
if (vm86->vm86_inited == 0)
return (EINVAL);
/* Go back to user mode if both flags are set. */
if ((eflags & PSL_VIP) && (eflags & PSL_VIF)) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_addr = (void *)regs->tf_eip;
trapsignal(td, &ksi);
}
if (vm86->vm86_has_vme) {
eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
(eflags & VME_USERCHANGE) | PSL_VM;
} else {
vm86->vm86_eflags = eflags; /* save VIF, VIP */
eflags = (tf->tf_eflags & ~VM_USERCHANGE) |
(eflags & VM_USERCHANGE) | PSL_VM;
}
bcopy(&ucp->uc_mcontext.mc_fs, tf, sizeof(struct trapframe));
tf->tf_eflags = eflags;
tf->tf_vm86_ds = tf->tf_ds;
tf->tf_vm86_es = tf->tf_es;
tf->tf_vm86_fs = tf->tf_fs;
tf->tf_vm86_gs = ucp->uc_mcontext.mc_gs;
tf->tf_ds = _udatasel;
tf->tf_es = _udatasel;
tf->tf_fs = _udatasel;
} else {
/*
* Don't allow users to change privileged or reserved flags.
*/
if (!EFL_SECURE(eflags, regs->tf_eflags)) {
uprintf(
"pid %d (%s): freebsd4_sigreturn eflags = 0x%x\n",
td->td_proc->p_pid, td->td_name, eflags);
return (EINVAL);
}
/*
* Don't allow users to load a valid privileged %cs. Let the
* hardware check for invalid selectors, excess privilege in
* other selectors, invalid %eip's and invalid %esp's.
*/
cs = ucp->uc_mcontext.mc_cs;
if (!CS_SECURE(cs)) {
uprintf("pid %d (%s): freebsd4_sigreturn cs = 0x%x\n",
td->td_proc->p_pid, td->td_name, cs);
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_trapno = T_PROTFLT;
ksi.ksi_addr = (void *)regs->tf_eip;
trapsignal(td, &ksi);
return (EINVAL);
}
bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs));
}
#if defined(COMPAT_43)
if (ucp->uc_mcontext.mc_onstack & 1)
td->td_sigstk.ss_flags |= SS_ONSTACK;
else
td->td_sigstk.ss_flags &= ~SS_ONSTACK;
#endif
kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
return (EJUSTRETURN);
}
#endif /* COMPAT_FREEBSD4 */
int
sys_sigreturn(struct thread *td, struct sigreturn_args *uap)
{
ucontext_t uc;
struct proc *p;
struct trapframe *regs;
ucontext_t *ucp;
char *xfpustate;
size_t xfpustate_len;
int cs, eflags, error, ret;
ksiginfo_t ksi;
p = td->td_proc;
error = copyin(uap->sigcntxp, &uc, sizeof(uc));
if (error != 0)
return (error);
ucp = &uc;
if ((ucp->uc_mcontext.mc_flags & ~_MC_FLAG_MASK) != 0) {
uprintf("pid %d (%s): sigreturn mc_flags %x\n", p->p_pid,
td->td_name, ucp->uc_mcontext.mc_flags);
return (EINVAL);
}
regs = td->td_frame;
eflags = ucp->uc_mcontext.mc_eflags;
if (eflags & PSL_VM) {
struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
struct vm86_kernel *vm86;
/*
* if pcb_ext == 0 or vm86_inited == 0, the user hasn't
* set up the vm86 area, and we can't enter vm86 mode.
*/
if (td->td_pcb->pcb_ext == 0)
return (EINVAL);
vm86 = &td->td_pcb->pcb_ext->ext_vm86;
if (vm86->vm86_inited == 0)
return (EINVAL);
/* Go back to user mode if both flags are set. */
if ((eflags & PSL_VIP) && (eflags & PSL_VIF)) {
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_addr = (void *)regs->tf_eip;
trapsignal(td, &ksi);
}
if (vm86->vm86_has_vme) {
eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
(eflags & VME_USERCHANGE) | PSL_VM;
} else {
vm86->vm86_eflags = eflags; /* save VIF, VIP */
eflags = (tf->tf_eflags & ~VM_USERCHANGE) |
(eflags & VM_USERCHANGE) | PSL_VM;
}
bcopy(&ucp->uc_mcontext.mc_fs, tf, sizeof(struct trapframe));
tf->tf_eflags = eflags;
tf->tf_vm86_ds = tf->tf_ds;
tf->tf_vm86_es = tf->tf_es;
tf->tf_vm86_fs = tf->tf_fs;
tf->tf_vm86_gs = ucp->uc_mcontext.mc_gs;
tf->tf_ds = _udatasel;
tf->tf_es = _udatasel;
tf->tf_fs = _udatasel;
} else {
/*
* Don't allow users to change privileged or reserved flags.
*/
if (!EFL_SECURE(eflags, regs->tf_eflags)) {
uprintf("pid %d (%s): sigreturn eflags = 0x%x\n",
td->td_proc->p_pid, td->td_name, eflags);
return (EINVAL);
}
/*
* Don't allow users to load a valid privileged %cs. Let the
* hardware check for invalid selectors, excess privilege in
* other selectors, invalid %eip's and invalid %esp's.
*/
cs = ucp->uc_mcontext.mc_cs;
if (!CS_SECURE(cs)) {
uprintf("pid %d (%s): sigreturn cs = 0x%x\n",
td->td_proc->p_pid, td->td_name, cs);
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGBUS;
ksi.ksi_code = BUS_OBJERR;
ksi.ksi_trapno = T_PROTFLT;
ksi.ksi_addr = (void *)regs->tf_eip;
trapsignal(td, &ksi);
return (EINVAL);
}
if ((uc.uc_mcontext.mc_flags & _MC_HASFPXSTATE) != 0) {
xfpustate_len = uc.uc_mcontext.mc_xfpustate_len;
if (xfpustate_len > cpu_max_ext_state_size -
sizeof(union savefpu)) {
uprintf(
"pid %d (%s): sigreturn xfpusave_len = 0x%zx\n",
p->p_pid, td->td_name, xfpustate_len);
return (EINVAL);
}
xfpustate = __builtin_alloca(xfpustate_len);
error = copyin(
(const void *)uc.uc_mcontext.mc_xfpustate,
xfpustate, xfpustate_len);
if (error != 0) {
uprintf(
"pid %d (%s): sigreturn copying xfpustate failed\n",
p->p_pid, td->td_name);
return (error);
}
} else {
xfpustate = NULL;
xfpustate_len = 0;
}
ret = set_fpcontext(td, &ucp->uc_mcontext, xfpustate,
xfpustate_len);
if (ret != 0)
return (ret);
bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs));
}
#if defined(COMPAT_43)
if (ucp->uc_mcontext.mc_onstack & 1)
td->td_sigstk.ss_flags |= SS_ONSTACK;
else
td->td_sigstk.ss_flags &= ~SS_ONSTACK;
#endif
kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
return (EJUSTRETURN);
}
/*
* Reset the hardware debug registers if they were in use.
* They won't have any meaning for the newly exec'd process.
*/
void
x86_clear_dbregs(struct pcb *pcb)
{
if ((pcb->pcb_flags & PCB_DBREGS) == 0)
return;
pcb->pcb_dr0 = 0;
pcb->pcb_dr1 = 0;
pcb->pcb_dr2 = 0;
pcb->pcb_dr3 = 0;
pcb->pcb_dr6 = 0;
pcb->pcb_dr7 = 0;
if (pcb == curpcb) {
/*
* Clear the debug registers on the running CPU,
* otherwise they will end up affecting the next
* process we switch to.
*/
reset_dbregs();
}
pcb->pcb_flags &= ~PCB_DBREGS;
}
#ifdef COMPAT_43
static void
setup_priv_lcall_gate(struct proc *p)
{
struct i386_ldt_args uap;
union descriptor desc;
u_int lcall_addr;
bzero(&uap, sizeof(uap));
uap.start = 0;
uap.num = 1;
lcall_addr = p->p_sysent->sv_psstrings - sz_lcall_tramp;
bzero(&desc, sizeof(desc));
desc.sd.sd_type = SDT_MEMERA;
desc.sd.sd_dpl = SEL_UPL;
desc.sd.sd_p = 1;
desc.sd.sd_def32 = 1;
desc.sd.sd_gran = 1;
desc.sd.sd_lolimit = 0xffff;
desc.sd.sd_hilimit = 0xf;
desc.sd.sd_lobase = lcall_addr;
desc.sd.sd_hibase = lcall_addr >> 24;
i386_set_ldt(curthread, &uap, &desc);
}
#endif
/*
* Reset registers to default values on exec.
*/
void
exec_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack)
{
struct trapframe *regs;
struct pcb *pcb;
register_t saved_eflags;
regs = td->td_frame;
pcb = td->td_pcb;
/* Reset pc->pcb_gs and %gs before possibly invalidating it. */
pcb->pcb_gs = _udatasel;
load_gs(_udatasel);
mtx_lock_spin(&dt_lock);
if (td->td_proc->p_md.md_ldt != NULL)
user_ldt_free(td);
else
mtx_unlock_spin(&dt_lock);
#ifdef COMPAT_43
if (td->td_proc->p_sysent->sv_psstrings !=
elf32_freebsd_sysvec.sv_psstrings)
setup_priv_lcall_gate(td->td_proc);
#endif
/*
* Reset the fs and gs bases. The values from the old address
* space do not make sense for the new program. In particular,
* gsbase might be the TLS base for the old program but the new
* program has no TLS now.
*/
set_fsbase(td, 0);
set_gsbase(td, 0);
/* Make sure edx is 0x0 on entry. Linux binaries depend on it. */
saved_eflags = regs->tf_eflags & PSL_T;
bzero((char *)regs, sizeof(struct trapframe));
regs->tf_eip = imgp->entry_addr;
regs->tf_esp = stack;
regs->tf_eflags = PSL_USER | saved_eflags;
regs->tf_ss = _udatasel;
regs->tf_ds = _udatasel;
regs->tf_es = _udatasel;
regs->tf_fs = _udatasel;
regs->tf_cs = _ucodesel;
/* PS_STRINGS value for BSD/OS binaries. It is 0 for non-BSD/OS. */
regs->tf_ebx = (register_t)imgp->ps_strings;
x86_clear_dbregs(pcb);
pcb->pcb_initial_npxcw = __INITIAL_NPXCW__;
/*
* Drop the FP state if we hold it, so that the process gets a
* clean FP state if it uses the FPU again.
*/
fpstate_drop(td);
}
int
fill_regs(struct thread *td, struct reg *regs)
{
struct pcb *pcb;
struct trapframe *tp;
tp = td->td_frame;
pcb = td->td_pcb;
regs->r_gs = pcb->pcb_gs;
return (fill_frame_regs(tp, regs));
}
int
fill_frame_regs(struct trapframe *tp, struct reg *regs)
{
regs->r_fs = tp->tf_fs;
regs->r_es = tp->tf_es;
regs->r_ds = tp->tf_ds;
regs->r_edi = tp->tf_edi;
regs->r_esi = tp->tf_esi;
regs->r_ebp = tp->tf_ebp;
regs->r_ebx = tp->tf_ebx;
regs->r_edx = tp->tf_edx;
regs->r_ecx = tp->tf_ecx;
regs->r_eax = tp->tf_eax;
regs->r_eip = tp->tf_eip;
regs->r_cs = tp->tf_cs;
regs->r_eflags = tp->tf_eflags;
regs->r_esp = tp->tf_esp;
regs->r_ss = tp->tf_ss;
regs->r_err = 0;
regs->r_trapno = 0;
return (0);
}
int
set_regs(struct thread *td, struct reg *regs)
{
struct pcb *pcb;
struct trapframe *tp;
tp = td->td_frame;
if (!EFL_SECURE(regs->r_eflags, tp->tf_eflags) ||
!CS_SECURE(regs->r_cs))
return (EINVAL);
pcb = td->td_pcb;
tp->tf_fs = regs->r_fs;
tp->tf_es = regs->r_es;
tp->tf_ds = regs->r_ds;
tp->tf_edi = regs->r_edi;
tp->tf_esi = regs->r_esi;
tp->tf_ebp = regs->r_ebp;
tp->tf_ebx = regs->r_ebx;
tp->tf_edx = regs->r_edx;
tp->tf_ecx = regs->r_ecx;
tp->tf_eax = regs->r_eax;
tp->tf_eip = regs->r_eip;
tp->tf_cs = regs->r_cs;
tp->tf_eflags = regs->r_eflags;
tp->tf_esp = regs->r_esp;
tp->tf_ss = regs->r_ss;
pcb->pcb_gs = regs->r_gs;
return (0);
}
int
fill_fpregs(struct thread *td, struct fpreg *fpregs)
{
KASSERT(td == curthread || TD_IS_SUSPENDED(td) ||
P_SHOULDSTOP(td->td_proc),
("not suspended thread %p", td));
npxgetregs(td);
if (cpu_fxsr)
npx_fill_fpregs_xmm(&get_pcb_user_save_td(td)->sv_xmm,
(struct save87 *)fpregs);
else
bcopy(&get_pcb_user_save_td(td)->sv_87, fpregs,
sizeof(*fpregs));
return (0);
}
int
set_fpregs(struct thread *td, struct fpreg *fpregs)
{
critical_enter();
if (cpu_fxsr)
npx_set_fpregs_xmm((struct save87 *)fpregs,
&get_pcb_user_save_td(td)->sv_xmm);
else
bcopy(fpregs, &get_pcb_user_save_td(td)->sv_87,
sizeof(*fpregs));
npxuserinited(td);
critical_exit();
return (0);
}
/*
* Get machine context.
*/
int
get_mcontext(struct thread *td, mcontext_t *mcp, int flags)
{
struct trapframe *tp;
struct segment_descriptor *sdp;
tp = td->td_frame;
PROC_LOCK(curthread->td_proc);
mcp->mc_onstack = sigonstack(tp->tf_esp);
PROC_UNLOCK(curthread->td_proc);
mcp->mc_gs = td->td_pcb->pcb_gs;
mcp->mc_fs = tp->tf_fs;
mcp->mc_es = tp->tf_es;
mcp->mc_ds = tp->tf_ds;
mcp->mc_edi = tp->tf_edi;
mcp->mc_esi = tp->tf_esi;
mcp->mc_ebp = tp->tf_ebp;
mcp->mc_isp = tp->tf_isp;
mcp->mc_eflags = tp->tf_eflags;
if (flags & GET_MC_CLEAR_RET) {
mcp->mc_eax = 0;
mcp->mc_edx = 0;
mcp->mc_eflags &= ~PSL_C;
} else {
mcp->mc_eax = tp->tf_eax;
mcp->mc_edx = tp->tf_edx;
}
mcp->mc_ebx = tp->tf_ebx;
mcp->mc_ecx = tp->tf_ecx;
mcp->mc_eip = tp->tf_eip;
mcp->mc_cs = tp->tf_cs;
mcp->mc_esp = tp->tf_esp;
mcp->mc_ss = tp->tf_ss;
mcp->mc_len = sizeof(*mcp);
get_fpcontext(td, mcp, NULL, 0);
sdp = &td->td_pcb->pcb_fsd;
mcp->mc_fsbase = sdp->sd_hibase << 24 | sdp->sd_lobase;
sdp = &td->td_pcb->pcb_gsd;
mcp->mc_gsbase = sdp->sd_hibase << 24 | sdp->sd_lobase;
mcp->mc_flags = 0;
mcp->mc_xfpustate = 0;
mcp->mc_xfpustate_len = 0;
bzero(mcp->mc_spare2, sizeof(mcp->mc_spare2));
return (0);
}
/*
* Set machine context.
*
* However, we don't set any but the user modifiable flags, and we won't
* touch the cs selector.
*/
int
set_mcontext(struct thread *td, mcontext_t *mcp)
{
struct trapframe *tp;
char *xfpustate;
int eflags, ret;
tp = td->td_frame;
if (mcp->mc_len != sizeof(*mcp) ||
(mcp->mc_flags & ~_MC_FLAG_MASK) != 0)
return (EINVAL);
eflags = (mcp->mc_eflags & PSL_USERCHANGE) |
(tp->tf_eflags & ~PSL_USERCHANGE);
if (mcp->mc_flags & _MC_HASFPXSTATE) {
if (mcp->mc_xfpustate_len > cpu_max_ext_state_size -
sizeof(union savefpu))
return (EINVAL);
xfpustate = __builtin_alloca(mcp->mc_xfpustate_len);
ret = copyin((void *)mcp->mc_xfpustate, xfpustate,
mcp->mc_xfpustate_len);
if (ret != 0)
return (ret);
} else
xfpustate = NULL;
ret = set_fpcontext(td, mcp, xfpustate, mcp->mc_xfpustate_len);
if (ret != 0)
return (ret);
tp->tf_fs = mcp->mc_fs;
tp->tf_es = mcp->mc_es;
tp->tf_ds = mcp->mc_ds;
tp->tf_edi = mcp->mc_edi;
tp->tf_esi = mcp->mc_esi;
tp->tf_ebp = mcp->mc_ebp;
tp->tf_ebx = mcp->mc_ebx;
tp->tf_edx = mcp->mc_edx;
tp->tf_ecx = mcp->mc_ecx;
tp->tf_eax = mcp->mc_eax;
tp->tf_eip = mcp->mc_eip;
tp->tf_eflags = eflags;
tp->tf_esp = mcp->mc_esp;
tp->tf_ss = mcp->mc_ss;
td->td_pcb->pcb_gs = mcp->mc_gs;
return (0);
}
static void
get_fpcontext(struct thread *td, mcontext_t *mcp, char *xfpusave,
size_t xfpusave_len)
{
size_t max_len, len;
mcp->mc_ownedfp = npxgetregs(td);
bcopy(get_pcb_user_save_td(td), &mcp->mc_fpstate[0],
sizeof(mcp->mc_fpstate));
mcp->mc_fpformat = npxformat();
if (!use_xsave || xfpusave_len == 0)
return;
max_len = cpu_max_ext_state_size - sizeof(union savefpu);
len = xfpusave_len;
if (len > max_len) {
len = max_len;
bzero(xfpusave + max_len, len - max_len);
}
mcp->mc_flags |= _MC_HASFPXSTATE;
mcp->mc_xfpustate_len = len;
bcopy(get_pcb_user_save_td(td) + 1, xfpusave, len);
}
static int
set_fpcontext(struct thread *td, mcontext_t *mcp, char *xfpustate,
size_t xfpustate_len)
{
int error;
if (mcp->mc_fpformat == _MC_FPFMT_NODEV)
return (0);
else if (mcp->mc_fpformat != _MC_FPFMT_387 &&
mcp->mc_fpformat != _MC_FPFMT_XMM)
return (EINVAL);
else if (mcp->mc_ownedfp == _MC_FPOWNED_NONE) {
/* We don't care what state is left in the FPU or PCB. */
fpstate_drop(td);
error = 0;
} else if (mcp->mc_ownedfp == _MC_FPOWNED_FPU ||
mcp->mc_ownedfp == _MC_FPOWNED_PCB) {
error = npxsetregs(td, (union savefpu *)&mcp->mc_fpstate,
xfpustate, xfpustate_len);
} else
return (EINVAL);
return (error);
}
static void
fpstate_drop(struct thread *td)
{
KASSERT(PCB_USER_FPU(td->td_pcb), ("fpstate_drop: kernel-owned fpu"));
critical_enter();
if (PCPU_GET(fpcurthread) == td)
npxdrop();
/*
* XXX force a full drop of the npx. The above only drops it if we
* owned it. npxgetregs() has the same bug in the !cpu_fxsr case.
*
* XXX I don't much like npxgetregs()'s semantics of doing a full
* drop. Dropping only to the pcb matches fnsave's behaviour.
* We only need to drop to !PCB_INITDONE in sendsig(). But
* sendsig() is the only caller of npxgetregs()... perhaps we just
* have too many layers.
*/
curthread->td_pcb->pcb_flags &= ~(PCB_NPXINITDONE |
PCB_NPXUSERINITDONE);
critical_exit();
}
int
fill_dbregs(struct thread *td, struct dbreg *dbregs)
{
struct pcb *pcb;
if (td == NULL) {
dbregs->dr[0] = rdr0();
dbregs->dr[1] = rdr1();
dbregs->dr[2] = rdr2();
dbregs->dr[3] = rdr3();
dbregs->dr[6] = rdr6();
dbregs->dr[7] = rdr7();
} else {
pcb = td->td_pcb;
dbregs->dr[0] = pcb->pcb_dr0;
dbregs->dr[1] = pcb->pcb_dr1;
dbregs->dr[2] = pcb->pcb_dr2;
dbregs->dr[3] = pcb->pcb_dr3;
dbregs->dr[6] = pcb->pcb_dr6;
dbregs->dr[7] = pcb->pcb_dr7;
}
dbregs->dr[4] = 0;
dbregs->dr[5] = 0;
return (0);
}
int
set_dbregs(struct thread *td, struct dbreg *dbregs)
{
struct pcb *pcb;
int i;
if (td == NULL) {
load_dr0(dbregs->dr[0]);
load_dr1(dbregs->dr[1]);
load_dr2(dbregs->dr[2]);
load_dr3(dbregs->dr[3]);
load_dr6(dbregs->dr[6]);
load_dr7(dbregs->dr[7]);
} else {
/*
* Don't let an illegal value for dr7 get set. Specifically,
* check for undefined settings. Setting these bit patterns
* result in undefined behaviour and can lead to an unexpected
* TRCTRAP.
*/
for (i = 0; i < 4; i++) {
if (DBREG_DR7_ACCESS(dbregs->dr[7], i) == 0x02)
return (EINVAL);
if (DBREG_DR7_LEN(dbregs->dr[7], i) == 0x02)
return (EINVAL);
}
pcb = td->td_pcb;
/*
* Don't let a process set a breakpoint that is not within the
* process's address space. If a process could do this, it
* could halt the system by setting a breakpoint in the kernel
* (if ddb was enabled). Thus, we need to check to make sure
* that no breakpoints are being enabled for addresses outside
* process's address space.
*
* XXX - what about when the watched area of the user's
* address space is written into from within the kernel
* ... wouldn't that still cause a breakpoint to be generated
* from within kernel mode?
*/
if (DBREG_DR7_ENABLED(dbregs->dr[7], 0)) {
/* dr0 is enabled */
if (dbregs->dr[0] >= VM_MAXUSER_ADDRESS)
return (EINVAL);
}
if (DBREG_DR7_ENABLED(dbregs->dr[7], 1)) {
/* dr1 is enabled */
if (dbregs->dr[1] >= VM_MAXUSER_ADDRESS)
return (EINVAL);
}
if (DBREG_DR7_ENABLED(dbregs->dr[7], 2)) {
/* dr2 is enabled */
if (dbregs->dr[2] >= VM_MAXUSER_ADDRESS)
return (EINVAL);
}
if (DBREG_DR7_ENABLED(dbregs->dr[7], 3)) {
/* dr3 is enabled */
if (dbregs->dr[3] >= VM_MAXUSER_ADDRESS)
return (EINVAL);
}
pcb->pcb_dr0 = dbregs->dr[0];
pcb->pcb_dr1 = dbregs->dr[1];
pcb->pcb_dr2 = dbregs->dr[2];
pcb->pcb_dr3 = dbregs->dr[3];
pcb->pcb_dr6 = dbregs->dr[6];
pcb->pcb_dr7 = dbregs->dr[7];
pcb->pcb_flags |= PCB_DBREGS;
}
return (0);
}
/*
* Return > 0 if a hardware breakpoint has been hit, and the
* breakpoint was in user space. Return 0, otherwise.
*/
int
user_dbreg_trap(register_t dr6)
{
u_int32_t dr7;
u_int32_t bp; /* breakpoint bits extracted from dr6 */
int nbp; /* number of breakpoints that triggered */
caddr_t addr[4]; /* breakpoint addresses */
int i;
bp = dr6 & DBREG_DR6_BMASK;
if (bp == 0) {
/*
* None of the breakpoint bits are set meaning this
* trap was not caused by any of the debug registers
*/
return (0);
}
dr7 = rdr7();
if ((dr7 & 0x000000ff) == 0) {
/*
* all GE and LE bits in the dr7 register are zero,
* thus the trap couldn't have been caused by the
* hardware debug registers
*/
return (0);
}
nbp = 0;
/*
* at least one of the breakpoints were hit, check to see
* which ones and if any of them are user space addresses
*/
if (bp & 0x01) {
addr[nbp++] = (caddr_t)rdr0();
}
if (bp & 0x02) {
addr[nbp++] = (caddr_t)rdr1();
}
if (bp & 0x04) {
addr[nbp++] = (caddr_t)rdr2();
}
if (bp & 0x08) {
addr[nbp++] = (caddr_t)rdr3();
}
for (i = 0; i < nbp; i++) {
if (addr[i] < (caddr_t)VM_MAXUSER_ADDRESS) {
/*
* addr[i] is in user space
*/
return (nbp);
}
}
/*
* None of the breakpoints are in user space.
*/
return (0);
}
