getcontext.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/param.h>
#include <sys/types.h>
#include <sys/vmparam.h>
#include <sys/systm.h>
#include <sys/signal.h>
#include <sys/stack.h>
#include <sys/regset.h>
#include <sys/privregs.h>
#include <sys/frame.h>
#include <sys/proc.h>
#include <sys/psw.h>
#include <sys/ucontext.h>
#include <sys/asm_linkage.h>
#include <sys/errno.h>
#include <sys/archsystm.h>
#include <sys/schedctl.h>
#include <sys/debug.h>
#include <sys/sysmacros.h>
/*
* Save user context.
*/
void
savecontext(ucontext_t *ucp, k_sigset_t mask)
{
proc_t *p = ttoproc(curthread);
klwp_t *lwp = ttolwp(curthread);
/*
* We unconditionally assign to every field through the end
* of the gregs, but we need to bzero() everything -after- that
* to avoid having any kernel stack garbage escape to userland.
*/
bzero(&ucp->uc_mcontext.fpregs, sizeof (ucontext_t) -
offsetof(ucontext_t, uc_mcontext.fpregs));
ucp->uc_flags = UC_ALL;
ucp->uc_link = (struct ucontext *)lwp->lwp_oldcontext;
/*
* Try to copyin() the ustack if one is registered. If the stack
* has zero size, this indicates that stack bounds checking has
* been disabled for this LWP. If stack bounds checking is disabled
* or the copyin() fails, we fall back to the legacy behavior.
*/
if (lwp->lwp_ustack == NULL ||
copyin((void *)lwp->lwp_ustack, &ucp->uc_stack,
sizeof (ucp->uc_stack)) != 0 ||
ucp->uc_stack.ss_size == 0) {
if (lwp->lwp_sigaltstack.ss_flags == SS_ONSTACK) {
ucp->uc_stack = lwp->lwp_sigaltstack;
} else {
ucp->uc_stack.ss_sp = p->p_usrstack - p->p_stksize;
ucp->uc_stack.ss_size = p->p_stksize;
ucp->uc_stack.ss_flags = 0;
}
}
getgregs(lwp, ucp->uc_mcontext.gregs);
if (lwp->lwp_pcb.pcb_fpu.fpu_flags & FPU_EN)
getfpregs(lwp, &ucp->uc_mcontext.fpregs);
else
ucp->uc_flags &= ~UC_FPU;
sigktou(&mask, &ucp->uc_sigmask);
lwptoregs(lwp)->r_ps &= ~PS_T; /* disable single step XXX */
}
/*
* Restore user context.
*/
void
restorecontext(ucontext_t *ucp)
{
kthread_t *t = curthread;
klwp_t *lwp = ttolwp(t);
lwp->lwp_oldcontext = (uintptr_t)ucp->uc_link;
if (ucp->uc_flags & UC_STACK) {
if (ucp->uc_stack.ss_flags == SS_ONSTACK)
lwp->lwp_sigaltstack = ucp->uc_stack;
else
lwp->lwp_sigaltstack.ss_flags &= ~SS_ONSTACK;
}
if (ucp->uc_flags & UC_CPU) {
setgregs(lwp, ucp->uc_mcontext.gregs);
lwp->lwp_eosys = JUSTRETURN;
t->t_post_sys = 1;
}
if (ucp->uc_flags & UC_FPU)
setfpregs(lwp, &ucp->uc_mcontext.fpregs);
if (ucp->uc_flags & UC_SIGMASK) {
proc_t *p = ttoproc(t);
mutex_enter(&p->p_lock);
schedctl_finish_sigblock(t);
sigutok(&ucp->uc_sigmask, &t->t_hold);
if (sigcheck(p, t))
t->t_sig_check = 1;
mutex_exit(&p->p_lock);
}
}
int
getsetcontext(int flag, void *arg)
{
ucontext_t uc;
ucontext_t *ucp;
klwp_t *lwp = ttolwp(curthread);
stack_t dummy_stk;
/*
* In future releases, when the ucontext structure grows,
* getcontext should be modified to only return the fields
* specified in the uc_flags. That way, the structure can grow
* and still be binary compatible will all .o's which will only
* have old fields defined in uc_flags
*/
switch (flag) {
default:
return (set_errno(EINVAL));
case GETCONTEXT:
if (schedctl_sigblock(curthread)) {
proc_t *p = ttoproc(curthread);
mutex_enter(&p->p_lock);
schedctl_finish_sigblock(curthread);
mutex_exit(&p->p_lock);
}
savecontext(&uc, curthread->t_hold);
if (copyout(&uc, arg, sizeof (uc)))
return (set_errno(EFAULT));
return (0);
case SETCONTEXT:
ucp = arg;
if (ucp == NULL)
exit(CLD_EXITED, 0);
/*
* Don't copyin filler or floating state unless we need it.
* The ucontext_t struct and fields are specified in the ABI.
*/
if (copyin(ucp, &uc, sizeof (ucontext_t) -
sizeof (uc.uc_filler) -
sizeof (uc.uc_mcontext.fpregs))) {
return (set_errno(EFAULT));
}
if ((uc.uc_flags & UC_FPU) &&
copyin(&ucp->uc_mcontext.fpregs, &uc.uc_mcontext.fpregs,
sizeof (uc.uc_mcontext.fpregs))) {
return (set_errno(EFAULT));
}
restorecontext(&uc);
if ((uc.uc_flags & UC_STACK) && (lwp->lwp_ustack != 0))
(void) copyout(&uc.uc_stack, (stack_t *)lwp->lwp_ustack,
sizeof (uc.uc_stack));
return (0);
case GETUSTACK:
if (copyout(&lwp->lwp_ustack, arg, sizeof (caddr_t)))
return (set_errno(EFAULT));
return (0);
case SETUSTACK:
if (copyin(arg, &dummy_stk, sizeof (dummy_stk)))
return (set_errno(EFAULT));
lwp->lwp_ustack = (uintptr_t)arg;
return (0);
}
}
#ifdef _SYSCALL32_IMPL
/*
* Save user context for 32-bit processes.
*/
void
savecontext32(ucontext32_t *ucp, k_sigset_t mask)
{
proc_t *p = ttoproc(curthread);
klwp_t *lwp = ttolwp(curthread);
bzero(&ucp->uc_mcontext.fpregs, sizeof (ucontext32_t) -
offsetof(ucontext32_t, uc_mcontext.fpregs));
ucp->uc_flags = UC_ALL;
ucp->uc_link = (caddr32_t)lwp->lwp_oldcontext;
if (lwp->lwp_ustack == NULL ||
copyin((void *)lwp->lwp_ustack, &ucp->uc_stack,
sizeof (ucp->uc_stack)) != 0 ||
ucp->uc_stack.ss_size == 0) {
if (lwp->lwp_sigaltstack.ss_flags == SS_ONSTACK) {
ucp->uc_stack.ss_sp =
(caddr32_t)(uintptr_t)lwp->lwp_sigaltstack.ss_sp;
ucp->uc_stack.ss_size =
(size32_t)lwp->lwp_sigaltstack.ss_size;
ucp->uc_stack.ss_flags = SS_ONSTACK;
} else {
ucp->uc_stack.ss_sp = (caddr32_t)(uintptr_t)
(p->p_usrstack - p->p_stksize);
ucp->uc_stack.ss_size = (size32_t)p->p_stksize;
ucp->uc_stack.ss_flags = 0;
}
}
getgregs32(lwp, ucp->uc_mcontext.gregs);
if (lwp->lwp_pcb.pcb_fpu.fpu_flags & FPU_EN)
getfpregs32(lwp, &ucp->uc_mcontext.fpregs);
else
ucp->uc_flags &= ~UC_FPU;
sigktou(&mask, &ucp->uc_sigmask);
lwptoregs(lwp)->r_ps &= ~PS_T;
}
int
getsetcontext32(int flag, void *arg)
{
ucontext32_t uc;
ucontext_t ucnat;
ucontext32_t *ucp;
klwp_t *lwp = ttolwp(curthread);
caddr32_t ustack32;
stack32_t dummy_stk32;
switch (flag) {
default:
return (set_errno(EINVAL));
case GETCONTEXT:
if (schedctl_sigblock(curthread)) {
proc_t *p = ttoproc(curthread);
mutex_enter(&p->p_lock);
schedctl_finish_sigblock(curthread);
mutex_exit(&p->p_lock);
}
savecontext32(&uc, curthread->t_hold);
if (copyout(&uc, arg, sizeof (uc)))
return (set_errno(EFAULT));
return (0);
case SETCONTEXT:
ucp = arg;
if (ucp == NULL)
exit(CLD_EXITED, 0);
if (copyin(ucp, &uc, sizeof (uc) -
sizeof (uc.uc_filler) -
sizeof (uc.uc_mcontext.fpregs))) {
return (set_errno(EFAULT));
}
if ((uc.uc_flags & UC_FPU) &&
copyin(&ucp->uc_mcontext.fpregs, &uc.uc_mcontext.fpregs,
sizeof (uc.uc_mcontext.fpregs))) {
return (set_errno(EFAULT));
}
ucontext_32ton(&uc, &ucnat);
restorecontext(&ucnat);
if ((uc.uc_flags & UC_STACK) && (lwp->lwp_ustack != 0))
(void) copyout(&uc.uc_stack,
(stack32_t *)lwp->lwp_ustack, sizeof (uc.uc_stack));
return (0);
case GETUSTACK:
ustack32 = (caddr32_t)lwp->lwp_ustack;
if (copyout(&ustack32, arg, sizeof (ustack32)))
return (set_errno(EFAULT));
return (0);
case SETUSTACK:
if (copyin(arg, &dummy_stk32, sizeof (dummy_stk32)))
return (set_errno(EFAULT));
lwp->lwp_ustack = (uintptr_t)arg;
return (0);
}
}
#endif /* _SYSCALL32_IMPL */