1
2 /*--------------------------------------------------------------------*/
3 /*--- Create/destroy signal delivery frames. ---*/
4 /*--- sigframe-amd64-darwin.c ---*/
5 /*--------------------------------------------------------------------*/
6
7 /*
8 This file is part of Valgrind, a dynamic binary instrumentation
9 framework.
10
11 Copyright (C) 2006-2011 OpenWorks Ltd
12 info@open-works.co.uk
13
14 This program is free software; you can redistribute it and/or
15 modify it under the terms of the GNU General Public License as
16 published by the Free Software Foundation; either version 2 of the
17 License, or (at your option) any later version.
18
19 This program is distributed in the hope that it will be useful, but
20 WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 General Public License for more details.
23
24 You should have received a copy of the GNU General Public License
25 along with this program; if not, write to the Free Software
26 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
27 02111-1307, USA.
28
29 The GNU General Public License is contained in the file COPYING.
30 */
31
32 #if defined(VGP_amd64_darwin)
33
34 #include "pub_core_basics.h"
35 #include "pub_core_vki.h"
36 #include "pub_core_vkiscnums.h"
37 #include "pub_core_libcsetjmp.h" // to keep _threadstate.h happy
38 #include "pub_core_threadstate.h"
39 #include "pub_core_aspacemgr.h"
40 #include "pub_core_libcbase.h"
41 #include "pub_core_libcassert.h"
42 #include "pub_core_libcprint.h"
43 #include "pub_core_machine.h"
44 #include "pub_core_options.h"
45 #include "pub_core_signals.h"
46 #include "pub_core_tooliface.h"
47 #include "pub_core_trampoline.h"
48 #include "pub_core_sigframe.h" /* self */
49
50
51 /* Cheap-ass hack copied from ppc32-aix5 code, just to get started.
52 Produce a frame with layout entirely of our own choosing. */
53
54 /* This module creates and removes signal frames for signal deliveries
55 on amd64-darwin. Kludgey; the machine state ought to be saved in a
56 ucontext and retrieved from it later, so the handler can modify it
57 and return. However .. for now .. just stick the vex guest state
58 in the frame and snarf it again later.
59
60 Also, don't bother with creating siginfo and ucontext in the
61 handler, although do point them somewhere non-faulting.
62
63 Frame should have a 16-aligned size, just in case that turns out to
64 be important for Darwin. (be conservative)
65 */
66 struct hacky_sigframe {
67 /* first word looks like a call to a 3-arg amd64-ELF function */
68 ULong returnAddr;
69 UChar lower_guardzone[512]; // put nothing here
70 VexGuestAMD64State gst;
71 VexGuestAMD64State gshadow1;
72 VexGuestAMD64State gshadow2;
73 vki_siginfo_t fake_siginfo;
74 struct vki_ucontext fake_ucontext;
75 UInt magicPI;
76 UInt sigNo_private;
77 vki_sigset_t mask; // saved sigmask; restore when hdlr returns
78 UInt __pad[2];
79 UChar upper_guardzone[512]; // put nothing here
80 // and don't zero it, since that might overwrite the client's
81 // stack redzone, at least on archs which have one
82 };
83
84
85 /* Extend the stack segment downwards if needed so as to ensure the
86 new signal frames are mapped to something. Return a Bool
87 indicating whether or not the operation was successful.
88 */
extend(ThreadState * tst,Addr addr,SizeT size)89 static Bool extend ( ThreadState *tst, Addr addr, SizeT size )
90 {
91 ThreadId tid = tst->tid;
92 /* For tracking memory events, indicate the entire frame has been
93 allocated. Except, don't mess with the area which
94 overlaps the previous frame's redzone. */
95 /* XXX is the following call really right? compared with the
96 amd64-linux version, this doesn't appear to handle the redzone
97 in the same way. */
98 VG_TRACK( new_mem_stack_signal,
99 addr - VG_STACK_REDZONE_SZB, size, tid );
100 return True;
101 }
102
103
104 /* Create a signal frame for thread 'tid'. Make a 3-arg frame
105 regardless of whether the client originally requested a 1-arg
106 version (no SA_SIGINFO) or a 3-arg one (SA_SIGINFO) since in the
107 former case, the amd64 calling conventions will simply cause the
108 extra 2 args to be ignored (inside the handler). (We hope!) */
VG_(sigframe_create)109 void VG_(sigframe_create) ( ThreadId tid,
110 Addr sp_top_of_frame,
111 const vki_siginfo_t *siginfo,
112 const struct vki_ucontext *siguc,
113 void *handler,
114 UInt flags,
115 const vki_sigset_t *mask,
116 void *restorer )
117 {
118 ThreadState* tst;
119 Addr rsp;
120 struct hacky_sigframe* frame;
121 Int sigNo = siginfo->si_signo;
122
123 vg_assert(VG_IS_16_ALIGNED(sizeof(struct hacky_sigframe)));
124
125 sp_top_of_frame &= ~0xfUL;
126 rsp = sp_top_of_frame - sizeof(struct hacky_sigframe);
127
128 tst = VG_(get_ThreadState)(tid);
129 if (!extend(tst, rsp, sp_top_of_frame - rsp))
130 return;
131
132 vg_assert(VG_IS_16_ALIGNED(rsp));
133
134 frame = (struct hacky_sigframe *) rsp;
135
136 /* clear it (very conservatively) (why so conservatively??) */
137 VG_(memset)(&frame->lower_guardzone, 0, 512);
138 VG_(memset)(&frame->gst, 0, sizeof(VexGuestAMD64State));
139 VG_(memset)(&frame->gshadow1, 0, sizeof(VexGuestAMD64State));
140 VG_(memset)(&frame->gshadow2, 0, sizeof(VexGuestAMD64State));
141 VG_(memset)(&frame->fake_siginfo, 0, sizeof(frame->fake_siginfo));
142 VG_(memset)(&frame->fake_ucontext, 0, sizeof(frame->fake_ucontext));
143
144 /* save stuff in frame */
145 frame->gst = tst->arch.vex;
146 frame->gshadow1 = tst->arch.vex_shadow1;
147 frame->gshadow2 = tst->arch.vex_shadow2;
148 frame->sigNo_private = sigNo;
149 frame->mask = tst->sig_mask;
150 frame->magicPI = 0x31415927;
151
152 /* Minimally fill in the siginfo and ucontext. Note, utter
153 lameness prevails. Be underwhelmed, be very underwhelmed. */
154 frame->fake_siginfo.si_signo = sigNo;
155 frame->fake_siginfo.si_code = siginfo->si_code;
156
157 /* Set up stack pointer */
158 vg_assert(rsp == (Addr)&frame->returnAddr);
159 VG_(set_SP)(tid, rsp);
160 VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_STACK_PTR, sizeof(ULong));
161
162 /* Set up program counter */
163 VG_(set_IP)(tid, (ULong)handler);
164 VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_INSTR_PTR, sizeof(ULong));
165
166 /* Set up RA and args for the frame */
167 VG_TRACK( pre_mem_write, Vg_CoreSignal, tid, "signal handler frame",
168 (Addr)frame, 1*sizeof(ULong) );
169 frame->returnAddr = (ULong)&VG_(amd64_darwin_SUBST_FOR_sigreturn);
170
171 /* XXX should tell the tool that these regs got written */
172 tst->arch.vex.guest_RDI = (ULong) sigNo;
173 tst->arch.vex.guest_RSI = (Addr) &frame->fake_siginfo;/* oh well */
174 tst->arch.vex.guest_RDX = (Addr) &frame->fake_ucontext; /* oh well */
175
176 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
177 (Addr)frame, 1*sizeof(ULong) );
178 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
179 (Addr)&frame->fake_siginfo, sizeof(frame->fake_siginfo));
180 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
181 (Addr)&frame->fake_ucontext, sizeof(frame->fake_ucontext));
182
183 if (VG_(clo_trace_signals))
184 VG_(message)(Vg_DebugMsg,
185 "sigframe_create (thread %d): next EIP=%#lx, next ESP=%#lx",
186 tid, (Addr)handler, (Addr)frame );
187 }
188
189
190 /* Remove a signal frame from thread 'tid's stack, and restore the CPU
191 state from it. Note, isRT is irrelevant here. */
VG_(sigframe_destroy)192 void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
193 {
194 ThreadState *tst;
195 Addr rsp;
196 Int sigNo;
197 struct hacky_sigframe* frame;
198
199 vg_assert(VG_(is_valid_tid)(tid));
200 tst = VG_(get_ThreadState)(tid);
201
202 /* Check that the stack frame looks valid */
203 rsp = VG_(get_SP)(tid);
204
205 /* why -8 ? because the signal handler's return will have popped
206 the return address of the stack; and the return address is the
207 lowest-addressed element of hacky_sigframe. */
208 frame = (struct hacky_sigframe*)(rsp - 8);
209 vg_assert(frame->magicPI == 0x31415927);
210 vg_assert(VG_IS_16_ALIGNED(frame));
211
212 /* restore the entire guest state, and shadows, from the
213 frame. Note, as per comments above, this is a kludge - should
214 restore it from saved ucontext. Oh well. */
215 tst->arch.vex = frame->gst;
216 tst->arch.vex_shadow1 = frame->gshadow1;
217 tst->arch.vex_shadow2 = frame->gshadow2;
218 tst->sig_mask = frame->mask;
219 tst->tmp_sig_mask = frame->mask;
220 sigNo = frame->sigNo_private;
221
222 if (VG_(clo_trace_signals))
223 VG_(message)(Vg_DebugMsg,
224 "sigframe_destroy (thread %d): valid magic; next RIP=%#llx",
225 tid, tst->arch.vex.guest_RIP);
226
227 VG_TRACK( die_mem_stack_signal,
228 (Addr)frame - VG_STACK_REDZONE_SZB,
229 sizeof(struct hacky_sigframe) );
230
231 /* tell the tools */
232 VG_TRACK( post_deliver_signal, tid, sigNo );
233 }
234
235 #endif // defined(VGP_amd64_darwin)
236
237 /*--------------------------------------------------------------------*/
238 /*--- end sigframe-amd64-darwin.c ---*/
239 /*--------------------------------------------------------------------*/
240