OpenSolaris_b135/uts/sparc/syscall/getcontext.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (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 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
#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/frame.h>
#include <sys/proc.h>
#include <sys/ucontext.h>
#include <sys/asm_linkage.h>
#include <sys/kmem.h>
#include <sys/errno.h>
#include <sys/archsystm.h>
#include <sys/fpu/fpusystm.h>
#include <sys/debug.h>
#include <sys/model.h>
#include <sys/cmn_err.h>
#include <sys/sysmacros.h>
#include <sys/privregs.h>
#include <sys/schedctl.h>
/*
* Save user context.
*/
void
savecontext(ucontext_t *ucp, k_sigset_t mask)
{
proc_t *p = ttoproc(curthread);
klwp_t *lwp = ttolwp(curthread);
/*
* We assign to every field through uc_mcontext.fpregs.fpu_en,
* but we have to bzero() everything after that.
*/
bzero(&ucp->uc_mcontext.fpregs.fpu_en, sizeof (ucontext_t) -
offsetof(ucontext_t, uc_mcontext.fpregs.fpu_en));
/*
* There are unused holes in the ucontext_t structure, zero-fill
* them so that we don't expose kernel data to the user.
*/
(&ucp->uc_flags)[1] = 0;
(&ucp->uc_stack.ss_flags)[1] = 0;
/*
* Flushing the user windows isn't strictly necessary; we do
* it to maintain backward compatibility.
*/
(void) flush_user_windows_to_stack(NULL);
ucp->uc_flags = UC_ALL;
ucp->uc_link = (ucontext_t *)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);
getasrs(lwp, ucp->uc_mcontext.asrs);
getfpregs(lwp, &ucp->uc_mcontext.fpregs);
getfpasrs(lwp, ucp->uc_mcontext.asrs);
if (ucp->uc_mcontext.fpregs.fpu_en == 0)
ucp->uc_flags &= ~UC_FPU;
ucp->uc_mcontext.gwins = (gwindows_t *)NULL;
/*
* Save signal mask.
*/
sigktou(&mask, &ucp->uc_sigmask);
}
void
restorecontext(ucontext_t *ucp)
{
kthread_t *t = curthread;
klwp_t *lwp = ttolwp(t);
mcontext_t *mcp = &ucp->uc_mcontext;
model_t model = lwp_getdatamodel(lwp);
(void) flush_user_windows_to_stack(NULL);
if (lwp->lwp_pcb.pcb_xregstat != XREGNONE)
xregrestore(lwp, 0);
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) {
if (mcp->gwins != 0)
setgwins(lwp, mcp->gwins);
setgregs(lwp, mcp->gregs);
if (model == DATAMODEL_LP64)
setasrs(lwp, mcp->asrs);
else
xregs_setgregs(lwp, xregs_getptr(lwp, ucp));
}
if (ucp->uc_flags & UC_FPU) {
fpregset_t *fp = &ucp->uc_mcontext.fpregs;
setfpregs(lwp, fp);
if (model == DATAMODEL_LP64)
setfpasrs(lwp, mcp->asrs);
else
xregs_setfpregs(lwp, xregs_getptr(lwp, ucp));
run_fpq(lwp, fp);
}
if (ucp->uc_flags & UC_SIGMASK) {
/*
* We don't need to acquire p->p_lock here;
* we are manipulating thread-private data.
*/
schedctl_finish_sigblock(t);
sigutok(&ucp->uc_sigmask, &t->t_hold);
if (sigcheck(ttoproc(t), t))
t->t_sig_check = 1;
}
}
int
getsetcontext(int flag, void *arg)
{
ucontext_t uc;
struct fq fpu_q[MAXFPQ]; /* to hold floating queue */
fpregset_t *fpp;
gwindows_t *gwin = NULL; /* to hold windows */
caddr_t xregs = NULL;
int xregs_size = 0;
extern int nwindows;
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:
schedctl_finish_sigblock(curthread);
savecontext(&uc, curthread->t_hold);
/*
* When using floating point it should not be possible to
* get here with a fpu_qcnt other than zero since we go
* to great pains to handle all outstanding FP exceptions
* before any system call code gets executed. However we
* clear fpu_q and fpu_qcnt here before copyout anyway -
* this will prevent us from interpreting the garbage we
* get back (when FP is not enabled) as valid queue data on
* a later setcontext(2).
*/
uc.uc_mcontext.fpregs.fpu_qcnt = 0;
uc.uc_mcontext.fpregs.fpu_q = (struct fq *)NULL;
if (copyout(&uc, arg, sizeof (ucontext_t)))
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) -
sizeof (uc.uc_mcontext.xrs) -
sizeof (uc.uc_mcontext.asrs) -
sizeof (uc.uc_mcontext.filler))) {
return (set_errno(EFAULT));
}
if (copyin(&ucp->uc_mcontext.xrs, &uc.uc_mcontext.xrs,
sizeof (uc.uc_mcontext.xrs))) {
return (set_errno(EFAULT));
}
fpp = &uc.uc_mcontext.fpregs;
if (uc.uc_flags & UC_FPU) {
/*
* Need to copyin floating point state
*/
if (copyin(&ucp->uc_mcontext.fpregs,
&uc.uc_mcontext.fpregs,
sizeof (uc.uc_mcontext.fpregs)))
return (set_errno(EFAULT));
/* if floating queue not empty */
if ((fpp->fpu_q) && (fpp->fpu_qcnt)) {
if (fpp->fpu_qcnt > MAXFPQ ||
fpp->fpu_q_entrysize <= 0 ||
fpp->fpu_q_entrysize > sizeof (struct fq))
return (set_errno(EINVAL));
if (copyin(fpp->fpu_q, fpu_q,
fpp->fpu_qcnt * fpp->fpu_q_entrysize))
return (set_errno(EFAULT));
fpp->fpu_q = fpu_q;
} else {
fpp->fpu_qcnt = 0; /* avoid confusion later */
}
} else {
fpp->fpu_qcnt = 0;
}
if (uc.uc_mcontext.gwins) { /* if windows in context */
size_t gwin_size;
/*
* We do the same computation here to determine
* how many bytes of gwindows_t to copy in that
* is also done in sendsig() to decide how many
* bytes to copy out. We just *know* that wbcnt
* is the first element of the structure.
*/
gwin = kmem_zalloc(sizeof (gwindows_t), KM_SLEEP);
if (copyin(uc.uc_mcontext.gwins,
&gwin->wbcnt, sizeof (gwin->wbcnt))) {
kmem_free(gwin, sizeof (gwindows_t));
return (set_errno(EFAULT));
}
if (gwin->wbcnt < 0 || gwin->wbcnt > nwindows) {
kmem_free(gwin, sizeof (gwindows_t));
return (set_errno(EINVAL));
}
gwin_size = gwin->wbcnt * sizeof (struct rwindow) +
SPARC_MAXREGWINDOW * sizeof (int *) + sizeof (long);
if (gwin_size > sizeof (gwindows_t) ||
copyin(uc.uc_mcontext.gwins, gwin, gwin_size)) {
kmem_free(gwin, sizeof (gwindows_t));
return (set_errno(EFAULT));
}
uc.uc_mcontext.gwins = gwin;
}
/*
* get extra register state or asrs if any exists
* there is no extra register state for _LP64 user programs
*/
xregs_clrptr(lwp, &uc);
if (copyin(&ucp->uc_mcontext.asrs, &uc.uc_mcontext.asrs,
sizeof (asrset_t))) {
/* Free up gwin structure if used */
if (gwin)
kmem_free(gwin, sizeof (gwindows_t));
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 (stack_t));
}
/*
* free extra register state area
*/
if (xregs_size)
kmem_free(xregs, xregs_size);
if (gwin)
kmem_free(gwin, sizeof (gwindows_t));
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, struct fq32 *dfq)
{
proc_t *p = ttoproc(curthread);
klwp_t *lwp = ttolwp(curthread);
fpregset_t fpregs;
/*
* We assign to every field through uc_mcontext.fpregs.fpu_en,
* but we have to bzero() everything after that.
*/
bzero(&ucp->uc_mcontext.fpregs.fpu_en, sizeof (ucontext32_t) -
offsetof(ucontext32_t, uc_mcontext.fpregs.fpu_en));
/*
* There is an unused hole in the ucontext32_t structure; zero-fill
* it so that we don't expose kernel data to the user.
*/
(&ucp->uc_stack.ss_flags)[1] = 0;
/*
* Flushing the user windows isn't strictly necessary; we do
* it to maintain backward compatibility.
*/
(void) flush_user_windows_to_stack(NULL);
ucp->uc_flags = UC_ALL;
ucp->uc_link = (caddr32_t)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.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);
getfpregs(lwp, &fpregs);
fpuregset_nto32(&fpregs, &ucp->uc_mcontext.fpregs, dfq);
if (ucp->uc_mcontext.fpregs.fpu_en == 0)
ucp->uc_flags &= ~UC_FPU;
ucp->uc_mcontext.gwins = (caddr32_t)NULL;
/*
* Save signal mask (the 32- and 64-bit sigset_t structures are
* identical).
*/
sigktou(&mask, (sigset_t *)&ucp->uc_sigmask);
}
int
getsetcontext32(int flag, void *arg)
{
ucontext32_t uc;
ucontext_t ucnat;
struct fq fpu_qnat[MAXFPQ]; /* to hold "native" floating queue */
struct fq32 fpu_q[MAXFPQ]; /* to hold 32 bit floating queue */
fpregset32_t *fpp;
gwindows32_t *gwin = NULL; /* to hold windows */
caddr_t xregs;
int xregs_size = 0;
extern int nwindows;
klwp_t *lwp = ttolwp(curthread);
ucontext32_t *ucp;
uint32_t ustack32;
stack32_t dummy_stk32;
/*
* 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:
schedctl_finish_sigblock(curthread);
savecontext32(&uc, curthread->t_hold, NULL);
/*
* When using floating point it should not be possible to
* get here with a fpu_qcnt other than zero since we go
* to great pains to handle all outstanding FP exceptions
* before any system call code gets executed. However we
* clear fpu_q and fpu_qcnt here before copyout anyway -
* this will prevent us from interpreting the garbage we
* get back (when FP is not enabled) as valid queue data on
* a later setcontext(2).
*/
uc.uc_mcontext.fpregs.fpu_qcnt = 0;
uc.uc_mcontext.fpregs.fpu_q = (caddr32_t)NULL;
if (copyout(&uc, arg, sizeof (ucontext32_t)))
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 (uc) - sizeof (uc.uc_filler) -
sizeof (uc.uc_mcontext.fpregs) -
sizeof (uc.uc_mcontext.xrs) -
sizeof (uc.uc_mcontext.filler))) {
return (set_errno(EFAULT));
}
if (copyin(&ucp->uc_mcontext.xrs, &uc.uc_mcontext.xrs,
sizeof (uc.uc_mcontext.xrs))) {
return (set_errno(EFAULT));
}
fpp = &uc.uc_mcontext.fpregs;
if (uc.uc_flags & UC_FPU) {
/*
* Need to copyin floating point state
*/
if (copyin(&ucp->uc_mcontext.fpregs,
&uc.uc_mcontext.fpregs,
sizeof (uc.uc_mcontext.fpregs)))
return (set_errno(EFAULT));
/* if floating queue not empty */
if ((fpp->fpu_q) && (fpp->fpu_qcnt)) {
if (fpp->fpu_qcnt > MAXFPQ ||
fpp->fpu_q_entrysize <= 0 ||
fpp->fpu_q_entrysize > sizeof (struct fq32))
return (set_errno(EINVAL));
if (copyin((void *)(uintptr_t)fpp->fpu_q, fpu_q,
fpp->fpu_qcnt * fpp->fpu_q_entrysize))
return (set_errno(EFAULT));
} else {
fpp->fpu_qcnt = 0; /* avoid confusion later */
}
} else {
fpp->fpu_qcnt = 0;
}
if (uc.uc_mcontext.gwins) { /* if windows in context */
size_t gwin_size;
/*
* We do the same computation here to determine
* how many bytes of gwindows_t to copy in that
* is also done in sendsig() to decide how many
* bytes to copy out. We just *know* that wbcnt
* is the first element of the structure.
*/
gwin = kmem_zalloc(sizeof (gwindows32_t), KM_SLEEP);
if (copyin((void *)(uintptr_t)uc.uc_mcontext.gwins,
&gwin->wbcnt, sizeof (gwin->wbcnt))) {
kmem_free(gwin, sizeof (gwindows32_t));
return (set_errno(EFAULT));
}
if (gwin->wbcnt < 0 || gwin->wbcnt > nwindows) {
kmem_free(gwin, sizeof (gwindows32_t));
return (set_errno(EINVAL));
}
gwin_size = gwin->wbcnt * sizeof (struct rwindow32) +
SPARC_MAXREGWINDOW * sizeof (caddr32_t) +
sizeof (int32_t);
if (gwin_size > sizeof (gwindows32_t) ||
copyin((void *)(uintptr_t)uc.uc_mcontext.gwins,
gwin, gwin_size)) {
kmem_free(gwin, sizeof (gwindows32_t));
return (set_errno(EFAULT));
}
/* restorecontext() should ignore this */
uc.uc_mcontext.gwins = (caddr32_t)0;
}
ucontext_32ton(&uc, &ucnat, fpu_q, fpu_qnat);
/*
* get extra register state if any exists
*/
if (xregs_hasptr32(lwp, &uc) &&
((xregs_size = xregs_getsize(curproc)) > 0)) {
xregs = kmem_zalloc(xregs_size, KM_SLEEP);
if (copyin((void *)(uintptr_t)xregs_getptr32(lwp, &uc),
xregs, xregs_size)) {
kmem_free(xregs, xregs_size);
if (gwin)
kmem_free(gwin, sizeof (gwindows32_t));
return (set_errno(EFAULT));
}
xregs_setptr(lwp, &ucnat, xregs);
} else {
xregs_clrptr(lwp, &ucnat);
}
restorecontext(&ucnat);
if ((uc.uc_flags & UC_STACK) && (lwp->lwp_ustack != 0)) {
(void) copyout(&uc.uc_stack,
(stack32_t *)lwp->lwp_ustack, sizeof (stack32_t));
}
if (gwin)
setgwins32(lwp, gwin);
/*
* free extra register state area
*/
if (xregs_size)
kmem_free(xregs, xregs_size);
if (gwin)
kmem_free(gwin, sizeof (gwindows32_t));
return (0);
case GETUSTACK:
ustack32 = (uint32_t)lwp->lwp_ustack;
if (copyout(&ustack32, arg, sizeof (caddr32_t)))
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 */