/*--------------------------------------------------------------------*/
/*--- Create/destroy signal delivery frames. ---*/
/*--- sigframe-arm-linux.c ---*/
/*--------------------------------------------------------------------*/
/*
This file is part of Valgrind, a dynamic binary instrumentation
framework.
Copyright (C) 2000-2012 Nicholas Nethercote
njn@valgrind.org
Copyright (C) 2004-2012 Paul Mackerras
paulus@samba.org
Copyright (C) 2008-2012 Evan Geller
gaze@bea.ms
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307, USA.
The GNU General Public License is contained in the file COPYING.
*/
#if defined(VGP_arm_linux)
#include "pub_core_basics.h"
#include "pub_core_vki.h"
#include "pub_core_vkiscnums.h"
#include "pub_core_libcsetjmp.h" // to keep _threadstate.h happy
#include "pub_core_threadstate.h"
#include "pub_core_aspacemgr.h"
#include "pub_core_libcbase.h"
#include "pub_core_libcassert.h"
#include "pub_core_libcprint.h"
#include "pub_core_machine.h"
#include "pub_core_options.h"
#include "pub_core_sigframe.h"
#include "pub_core_signals.h"
#include "pub_core_tooliface.h"
#include "pub_core_trampoline.h"
#include "pub_core_transtab.h" // VG_(discard_translations)
/* This uses the hack of dumping the vex guest state along with both
shadows in the frame, and restoring it afterwards from there,
rather than pulling it out of the ucontext. That means that signal
handlers which modify the ucontext and then return, expecting their
modifications to take effect, will have those modifications
ignored. This could be fixed properly with an hour or so more
effort. */
struct vg_sig_private {
UInt magicPI;
UInt sigNo_private;
VexGuestARMState vex;
VexGuestARMState vex_shadow1;
VexGuestARMState vex_shadow2;
};
struct sigframe {
struct vki_ucontext uc;
unsigned long retcode[2];
struct vg_sig_private vp;
};
struct rt_sigframe {
vki_siginfo_t info;
struct sigframe sig;
};
static Bool extend ( ThreadState *tst, Addr addr, SizeT size )
{
ThreadId tid = tst->tid;
NSegment const* stackseg = NULL;
if (VG_(extend_stack)(addr, tst->client_stack_szB)) {
stackseg = VG_(am_find_nsegment)(addr);
if (0 && stackseg)
VG_(printf)("frame=%#lx seg=%#lx-%#lx\n",
addr, stackseg->start, stackseg->end);
}
if (stackseg == NULL || !stackseg->hasR || !stackseg->hasW) {
VG_(message)(
Vg_UserMsg,
"Can't extend stack to %#lx during signal delivery for thread %d:",
addr, tid);
if (stackseg == NULL)
VG_(message)(Vg_UserMsg, " no stack segment");
else
VG_(message)(Vg_UserMsg, " too small or bad protection modes");
/* set SIGSEGV to default handler */
VG_(set_default_handler)(VKI_SIGSEGV);
VG_(synth_fault_mapping)(tid, addr);
/* The whole process should be about to die, since the default
action of SIGSEGV to kill the whole process. */
return False;
}
/* For tracking memory events, indicate the entire frame has been
allocated. */
VG_TRACK( new_mem_stack_signal, addr - VG_STACK_REDZONE_SZB,
size + VG_STACK_REDZONE_SZB, tid );
return True;
}
static void synth_ucontext( ThreadId tid, const vki_siginfo_t *si,
UWord trapno, UWord err, const vki_sigset_t *set,
struct vki_ucontext *uc){
ThreadState *tst = VG_(get_ThreadState)(tid);
struct vki_sigcontext *sc = &uc->uc_mcontext;
VG_(memset)(uc, 0, sizeof(*uc));
uc->uc_flags = 0;
uc->uc_link = 0;
uc->uc_sigmask = *set;
uc->uc_stack = tst->altstack;
# define SC2(reg,REG) sc->arm_##reg = tst->arch.vex.guest_##REG
SC2(r0,R0);
SC2(r1,R1);
SC2(r2,R2);
SC2(r3,R3);
SC2(r4,R4);
SC2(r5,R5);
SC2(r6,R6);
SC2(r7,R7);
SC2(r8,R8);
SC2(r9,R9);
SC2(r10,R10);
SC2(fp,R11);
SC2(ip,R12);
SC2(sp,R13);
SC2(lr,R14);
SC2(pc,R15T);
# undef SC2
sc->trap_no = trapno;
sc->error_code = err;
sc->fault_address = (UInt)si->_sifields._sigfault._addr;
}
static void build_sigframe(ThreadState *tst,
struct sigframe *frame,
const vki_siginfo_t *siginfo,
const struct vki_ucontext *siguc,
void *handler, UInt flags,
const vki_sigset_t *mask,
void *restorer){
UWord trapno;
UWord err;
Int sigNo = siginfo->si_signo;
struct vg_sig_private *priv = &frame->vp;
VG_TRACK( pre_mem_write, Vg_CoreSignal, tst->tid, "signal handler frame",
(Addr)frame, offsetof(struct sigframe, vp));
if(siguc) {
trapno = siguc->uc_mcontext.trap_no;
err = siguc->uc_mcontext.error_code;
} else {
trapno = 0;
err = 0;
}
synth_ucontext(tst->tid, siginfo, trapno, err, mask, &frame->uc);
VG_TRACK( post_mem_write, Vg_CoreSignal, tst->tid,
(Addr)frame, offsetof(struct sigframe, vp));
priv->magicPI = 0x31415927;
priv->sigNo_private = sigNo;
priv->vex = tst->arch.vex;
priv->vex_shadow1 = tst->arch.vex_shadow1;
priv->vex_shadow2 = tst->arch.vex_shadow2;
}
/* EXPORTED */
void VG_(sigframe_create)( ThreadId tid,
Addr sp_top_of_frame,
const vki_siginfo_t *siginfo,
const struct vki_ucontext *siguc,
void *handler,
UInt flags,
const vki_sigset_t *mask,
void *restorer )
{
// struct vg_sig_private *priv;
Addr sp = sp_top_of_frame;
ThreadState *tst;
Int sigNo = siginfo->si_signo;
// Addr faultaddr;
UInt size;
tst = VG_(get_ThreadState)(tid);
size = flags & VKI_SA_SIGINFO ? sizeof(struct rt_sigframe) :
sizeof(struct sigframe);
sp -= size;
sp = VG_ROUNDDN(sp, 16);
if(!extend(tst, sp, size))
I_die_here; // XXX Incorrect behavior
if (flags & VKI_SA_SIGINFO){
struct rt_sigframe *rsf = (struct rt_sigframe *)sp;
/* Track our writes to siginfo */
VG_TRACK( pre_mem_write, Vg_CoreSignal, tst->tid, /* VVVVV */
"signal handler siginfo", (Addr)rsf,
offsetof(struct rt_sigframe, sig));
VG_(memcpy)(&rsf->info, siginfo, sizeof(vki_siginfo_t));
if(sigNo == VKI_SIGILL && siginfo->si_code > 0) {
rsf->info._sifields._sigfault._addr = (Addr *) (tst)->arch.vex.guest_R12; /* IP */
}
VG_TRACK( post_mem_write, Vg_CoreSignal, tst->tid, /* ^^^^^ */
(Addr)rsf, offsetof(struct rt_sigframe, sig));
build_sigframe(tst, &rsf->sig, siginfo, siguc,
handler, flags, mask, restorer);
tst->arch.vex.guest_R1 = (Addr)&rsf->info;
tst->arch.vex.guest_R2 = (Addr)&rsf->sig.uc;
}
else {
build_sigframe(tst, (struct sigframe *)sp, siginfo, siguc,
handler, flags, mask, restorer);
}
VG_(set_SP)(tid, sp);
VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_STACK_PTR,
sizeof(Addr));
tst->arch.vex.guest_R0 = sigNo;
if (flags & VKI_SA_RESTORER)
tst->arch.vex.guest_R14 = (Addr)restorer;
else
tst->arch.vex.guest_R14
= (flags & VKI_SA_SIGINFO)
? (Addr)&VG_(arm_linux_SUBST_FOR_rt_sigreturn)
: (Addr)&VG_(arm_linux_SUBST_FOR_sigreturn);
tst->arch.vex.guest_R15T = (Addr) handler; /* R15 == PC */
}
/*------------------------------------------------------------*/
/*--- Destroying signal frames ---*/
/*------------------------------------------------------------*/
/* EXPORTED */
void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
{
ThreadState *tst;
struct vg_sig_private *priv;
Addr sp;
UInt frame_size;
struct vki_sigcontext *mc;
Int sigNo;
Bool has_siginfo = isRT;
vg_assert(VG_(is_valid_tid)(tid));
tst = VG_(get_ThreadState)(tid);
sp = tst->arch.vex.guest_R13;
if (has_siginfo) {
struct rt_sigframe *frame = (struct rt_sigframe *)sp;
frame_size = sizeof(*frame);
mc = &frame->sig.uc.uc_mcontext;
priv = &frame->sig.vp;
vg_assert(priv->magicPI == 0x31415927);
tst->sig_mask = frame->sig.uc.uc_sigmask;
} else {
struct sigframe *frame = (struct sigframe *)sp;
frame_size = sizeof(*frame);
mc = &frame->uc.uc_mcontext;
priv = &frame->vp;
vg_assert(priv->magicPI == 0x31415927);
tst->sig_mask = frame->uc.uc_sigmask;
/*tst->sig_mask.sig[0] = frame->uc.uc_mcontext.oldmask;
tst->sig_mask.sig[1] = frame->uc.uc_mcontext._unused[3];
VG_(printf)("Setting signmask to %08x%08x\n",tst->sig_mask[0],tst->sig_mask[1]);
*/
}
tst->tmp_sig_mask = tst->sig_mask;
sigNo = priv->sigNo_private;
//XXX: restore regs
# define REST(reg,REG) tst->arch.vex.guest_##REG = mc->arm_##reg;
REST(r0,R0);
REST(r1,R1);
REST(r2,R2);
REST(r3,R3);
REST(r4,R4);
REST(r5,R5);
REST(r6,R6);
REST(r7,R7);
REST(r8,R8);
REST(r9,R9);
REST(r10,R10);
REST(fp,R11);
REST(ip,R12);
REST(sp,R13);
REST(lr,R14);
REST(pc,R15T);
# undef REST
/* Uh, the next line makes all the REST() above pointless. */
tst->arch.vex = priv->vex;
tst->arch.vex_shadow1 = priv->vex_shadow1;
tst->arch.vex_shadow2 = priv->vex_shadow2;
VG_TRACK( die_mem_stack_signal, sp - VG_STACK_REDZONE_SZB,
frame_size + VG_STACK_REDZONE_SZB );
if (VG_(clo_trace_signals))
VG_(message)(Vg_DebugMsg,
"vg_pop_signal_frame (thread %d): "
"isRT=%d valid magic; PC=%#x\n",
tid, has_siginfo, tst->arch.vex.guest_R15T);
/* tell the tools */
VG_TRACK( post_deliver_signal, tid, sigNo );
}
#endif // defined(VGP_arm_linux)
/*--------------------------------------------------------------------*/
/*--- end sigframe-arm-linux.c ---*/
/*--------------------------------------------------------------------*/