1
2 /*--------------------------------------------------------------------*/
3 /*--- Create/destroy signal delivery frames. ---*/
4 /*--- sigframe-ppc64-linux.c ---*/
5 /*--------------------------------------------------------------------*/
6
7 /*
8 This file is part of Valgrind, a dynamic binary instrumentation
9 framework.
10
11 Copyright (C) 2000-2013 Nicholas Nethercote
12 njn@valgrind.org
13 Copyright (C) 2004-2013 Paul Mackerras
14 paulus@samba.org
15
16 This program is free software; you can redistribute it and/or
17 modify it under the terms of the GNU General Public License as
18 published by the Free Software Foundation; either version 2 of the
19 License, or (at your option) any later version.
20
21 This program is distributed in the hope that it will be useful, but
22 WITHOUT ANY WARRANTY; without even the implied warranty of
23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 General Public License for more details.
25
26 You should have received a copy of the GNU General Public License
27 along with this program; if not, write to the Free Software
28 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
29 02111-1307, USA.
30
31 The GNU General Public License is contained in the file COPYING.
32 */
33
34 #if defined(VGP_ppc64be_linux) || defined(VGP_ppc64le_linux)
35
36 #include "pub_core_basics.h"
37 #include "pub_core_vki.h"
38 #include "pub_core_vkiscnums.h"
39 #include "pub_core_threadstate.h"
40 #include "pub_core_aspacemgr.h"
41 #include "pub_core_libcbase.h"
42 #include "pub_core_libcassert.h"
43 #include "pub_core_libcprint.h"
44 #include "pub_core_machine.h"
45 #include "pub_core_options.h"
46 #include "pub_core_sigframe.h"
47 #include "pub_core_signals.h"
48 #include "pub_core_tooliface.h"
49 #include "pub_core_trampoline.h"
50 #include "pub_core_transtab.h" // VG_(discard_translations)
51 #include "priv_sigframe.h"
52
53 /* This module creates and removes signal frames for signal deliveries
54 on ppc64-linux.
55
56 Note, this file contains kernel-specific knowledge in the form of
57 'struct sigframe' and 'struct rt_sigframe'. How does that relate
58 to the vki kernel interface stuff?
59
60 Either a 'struct sigframe' or a 'struct rtsigframe' is pushed
61 onto the client's stack. This contains a subsidiary
62 vki_ucontext. That holds the vcpu's state across the signal,
63 so that the sighandler can mess with the vcpu state if it
64 really wants.
65
66 FIXME: sigcontexting is basically broken for the moment. When
67 delivering a signal, the integer registers and %eflags are
68 correctly written into the sigcontext, however the FP and SSE state
69 is not. When returning from a signal, only the integer registers
70 are restored from the sigcontext; the rest of the CPU state is
71 restored to what it was before the signal.
72
73 This will be fixed.
74 */
75
76
77 /*------------------------------------------------------------*/
78 /*--- Signal frame layouts ---*/
79 /*------------------------------------------------------------*/
80
81 // A structure in which to save the application's registers
82 // during the execution of signal handlers.
83
84 // On ppc64-linux, rt_sigframe is used for all signals.
85
86 // In theory, so long as we get the arguments to the handler function
87 // right, it doesn't matter what the exact layout of the rest of the
88 // frame is. Unfortunately, things like gcc's exception unwinding
89 // make assumptions about the locations of various parts of the frame,
90 // so we need to duplicate it exactly.
91
92 /* Many of these byzantine details derived from
93 linux-2.6.13/arch/ppc64/kernel/signal.c */
94
95 #define TRAMP_SIZE 6 /* who knows why - it only needs to be 2. */
96
97 /* Structure containing bits of information that we want to save
98 on signal delivery. */
99 struct vg_sig_private {
100 UInt magicPI;
101 UInt sigNo_private;
102 ULong _unused; /* makes the struct size be zero % 16 */
103 VexGuestPPC64State vex_shadow1;
104 VexGuestPPC64State vex_shadow2;
105 };
106
107 /* Structure put on stack for all signal handlers. */
108 struct rt_sigframe {
109 struct vki_ucontext uc;
110 ULong _unused[2];
111 UInt tramp[TRAMP_SIZE];
112 struct vki_siginfo* pinfo;
113 void* puc;
114 vki_siginfo_t info;
115 struct vg_sig_private priv;
116 UChar abigap[288]; // unused
117 };
118
119 #define SET_SIGNAL_LR(zztst, zzval) \
120 do { tst->arch.vex.guest_LR = (zzval); \
121 VG_TRACK( post_reg_write, Vg_CoreSignal, tst->tid, \
122 offsetof(VexGuestPPC64State,guest_LR), \
123 sizeof(UWord) ); \
124 } while (0)
125
126 #define SET_SIGNAL_GPR(zztst, zzn, zzval) \
127 do { tst->arch.vex.guest_GPR##zzn = (zzval); \
128 VG_TRACK( post_reg_write, Vg_CoreSignal, tst->tid, \
129 offsetof(VexGuestPPC64State,guest_GPR##zzn), \
130 sizeof(UWord) ); \
131 } while (0)
132
133
134
135 /* EXPORTED */
VG_(sigframe_create)136 void VG_(sigframe_create)( ThreadId tid,
137 Addr sp_top_of_frame,
138 const vki_siginfo_t *siginfo,
139 const struct vki_ucontext *siguc,
140 void *handler,
141 UInt flags,
142 const vki_sigset_t *mask,
143 void *restorer )
144 {
145 struct vg_sig_private* priv;
146 Addr sp;
147 ThreadState* tst;
148 Int sigNo = siginfo->si_signo;
149 /* Addr faultaddr; */ /* UNUSED */
150 struct rt_sigframe* frame;
151
152 /* Stack must be 16-byte aligned */
153 vg_assert(VG_IS_16_ALIGNED(sizeof(struct vg_sig_private)));
154 vg_assert(VG_IS_16_ALIGNED(sizeof(struct rt_sigframe)));
155
156 sp_top_of_frame &= ~0xf;
157 sp = sp_top_of_frame - sizeof(struct rt_sigframe);
158
159 tst = VG_(get_ThreadState)(tid);
160 if (! ML_(sf_maybe_extend_stack)(tst, sp, sp_top_of_frame - sp, flags))
161 return;
162
163 vg_assert(VG_IS_16_ALIGNED(sp));
164
165 frame = (struct rt_sigframe *) sp;
166
167 /* clear it (conservatively) */
168 VG_(memset)(frame, 0, sizeof(*frame));
169
170 /////////
171 frame->pinfo = &frame->info;
172 frame->puc = &frame->uc;
173
174 frame->uc.uc_flags = 0;
175 frame->uc.uc_link = 0;
176 /////////
177
178 /* Set up the stack chain pointer */
179 VG_TRACK( pre_mem_write, Vg_CoreSignal, tid, "signal handler frame",
180 sp, sizeof(UWord) );
181 *(Addr *)sp = tst->arch.vex.guest_GPR1;
182 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
183 sp, sizeof(UWord) );
184
185 /* UNUSED:
186 faultaddr = (Addr)siginfo->_sifields._sigfault._addr;
187 if (sigNo == VKI_SIGILL && siginfo->si_code > 0)
188 faultaddr = tst->arch.vex.guest_CIA;
189 */
190
191 VG_(memcpy)(&frame->info, siginfo, sizeof(*siginfo));
192 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
193 (Addr)&frame->info, sizeof(frame->info) );
194
195 frame->uc.uc_flags = 0;
196 frame->uc.uc_link = 0;
197 frame->uc.uc_stack = tst->altstack;
198 frame->uc.uc_sigmask = tst->sig_mask;
199 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
200 (Addr)(&frame->uc), sizeof(frame->uc) );
201
202 # define DO(gpr) frame->uc.uc_mcontext.gp_regs[VKI_PT_R0+gpr] \
203 = tst->arch.vex.guest_GPR##gpr
204 DO(0); DO(1); DO(2); DO(3); DO(4); DO(5); DO(6); DO(7);
205 DO(8); DO(9); DO(10); DO(11); DO(12); DO(13); DO(14); DO(15);
206 DO(16); DO(17); DO(18); DO(19); DO(20); DO(21); DO(22); DO(23);
207 DO(24); DO(25); DO(26); DO(27); DO(28); DO(29); DO(30); DO(31);
208 # undef DO
209
210 frame->uc.uc_mcontext.gp_regs[VKI_PT_NIP] = tst->arch.vex.guest_CIA;
211 #ifdef VGP_ppc64le_linux
212 frame->uc.uc_mcontext.gp_regs[VKI_PT_MSR] = 0xf033; /* pretty arbitrary */
213 #else
214 frame->uc.uc_mcontext.gp_regs[VKI_PT_MSR] = 0xf032; /* pretty arbitrary */
215 #endif
216 frame->uc.uc_mcontext.gp_regs[VKI_PT_ORIG_R3] = tst->arch.vex.guest_GPR3;
217 frame->uc.uc_mcontext.gp_regs[VKI_PT_CTR] = tst->arch.vex.guest_CTR;
218 frame->uc.uc_mcontext.gp_regs[VKI_PT_LNK] = tst->arch.vex.guest_LR;
219 frame->uc.uc_mcontext.gp_regs[VKI_PT_XER] = LibVEX_GuestPPC64_get_XER(
220 &tst->arch.vex);
221 frame->uc.uc_mcontext.gp_regs[VKI_PT_CCR] = LibVEX_GuestPPC64_get_CR(
222 &tst->arch.vex);
223 //mc->mc_gregs[VKI_PT_MQ] = 0;
224 //mc->mc_gregs[VKI_PT_TRAP] = 0;
225 //mc->mc_gregs[VKI_PT_DAR] = fault_addr;
226 //mc->mc_gregs[VKI_PT_DSISR] = 0;
227 //mc->mc_gregs[VKI_PT_RESULT] = 0;
228
229 /* XXX should do FP and vector regs */
230
231 /* set up signal return trampoline */
232 /* NB. 5 Sept 07. mc->mc_pad[0..1] used to contain a the code to
233 which the signal handler returns, and it just did sys_sigreturn
234 or sys_rt_sigreturn. But this doesn't work if the stack is
235 non-executable, and it isn't consistent with the x86-linux and
236 amd64-linux scheme for removing the stack frame. So instead be
237 consistent and use a stub in m_trampoline. Then it doesn't
238 matter whether or not the (guest) stack is executable. This
239 fixes #149519 and #145837. */
240 frame->tramp[0] = 0; /* invalid */
241 frame->tramp[1] = 0; /* invalid */
242 VG_TRACK(post_mem_write, Vg_CoreSignal, tst->tid,
243 (Addr)&frame->tramp, sizeof(frame->tramp));
244
245 /* invalidate any translation of this area */
246 VG_(discard_translations)( (Addr)&frame->tramp[0],
247 sizeof(frame->tramp), "stack_mcontext" );
248
249 /* set the signal handler to return to the trampoline */
250 SET_SIGNAL_LR(tst, (Addr)&VG_(ppc64_linux_SUBST_FOR_rt_sigreturn));
251
252 /* Stack pointer for the handler .. (note, back chain set
253 earlier) */
254 SET_SIGNAL_GPR(tid, 1, sp);
255
256 /* Args for the handler .. */
257 SET_SIGNAL_GPR(tid, 3, sigNo);
258 SET_SIGNAL_GPR(tid, 4, (Addr) &frame->info);
259 SET_SIGNAL_GPR(tid, 5, (Addr) &frame->uc);
260 /* the kernel sets this, though it doesn't seem to be in the ABI */
261 SET_SIGNAL_GPR(tid, 6, (Addr) &frame->info);
262
263 /* Handler is in fact a standard ppc64-linux function descriptor,
264 so extract the function entry point and also the toc ptr to use. */
265 #if defined(VGP_ppc64be_linux)
266 SET_SIGNAL_GPR(tid, 2, (Addr) ((ULong*)handler)[1]);
267 tst->arch.vex.guest_CIA = (Addr) ((ULong*)handler)[0];
268 #else
269 SET_SIGNAL_GPR(tid, 12, (Addr) handler);
270 tst->arch.vex.guest_CIA = (Addr) handler;
271 #endif
272 priv = &frame->priv;
273 priv->magicPI = 0x31415927;
274 priv->sigNo_private = sigNo;
275 priv->vex_shadow1 = tst->arch.vex_shadow1;
276 priv->vex_shadow2 = tst->arch.vex_shadow2;
277
278 if (0)
279 VG_(printf)("pushed signal frame; %%R1 now = %#lx, "
280 "next %%CIA = %#llx, status=%d\n",
281 sp, tst->arch.vex.guest_CIA, tst->status);
282 }
283
284
285 /*------------------------------------------------------------*/
286 /*--- Destroying signal frames ---*/
287 /*------------------------------------------------------------*/
288
289 /* EXPORTED */
VG_(sigframe_destroy)290 void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
291 {
292 ThreadState *tst;
293 struct vg_sig_private *priv;
294 Addr sp;
295 UInt frame_size;
296 struct rt_sigframe *frame;
297 Int sigNo;
298 Bool has_siginfo = isRT;
299
300 vg_assert(VG_(is_valid_tid)(tid));
301 tst = VG_(get_ThreadState)(tid);
302
303 /* Check that the stack frame looks valid */
304 sp = tst->arch.vex.guest_GPR1;
305 vg_assert(VG_IS_16_ALIGNED(sp));
306 /* JRS 17 Nov 05: This code used to check that *sp -- which should
307 have been set by the stwu at the start of the handler -- points
308 to just above the frame (ie, the previous frame). However, that
309 isn't valid when delivering signals on alt stacks. So I removed
310 it. The frame is still sanity-checked using the priv->magicPI
311 field. */
312
313 frame = (struct rt_sigframe *)sp;
314 frame_size = sizeof(*frame);
315 priv = &frame->priv;
316 vg_assert(priv->magicPI == 0x31415927);
317 tst->sig_mask = frame->uc.uc_sigmask;
318 tst->tmp_sig_mask = tst->sig_mask;
319
320 sigNo = priv->sigNo_private;
321
322 # define DO(gpr) tst->arch.vex.guest_GPR##gpr \
323 = frame->uc.uc_mcontext.gp_regs[VKI_PT_R0+gpr]
324 DO(0); DO(1); DO(2); DO(3); DO(4); DO(5); DO(6); DO(7);
325 DO(8); DO(9); DO(10); DO(11); DO(12); DO(13); DO(14); DO(15);
326 DO(16); DO(17); DO(18); DO(19); DO(20); DO(21); DO(22); DO(23);
327 DO(24); DO(25); DO(26); DO(27); DO(28); DO(29); DO(30); DO(31);
328 # undef DO
329
330 tst->arch.vex.guest_CIA = frame->uc.uc_mcontext.gp_regs[VKI_PT_NIP];
331
332 LibVEX_GuestPPC64_put_CR( frame->uc.uc_mcontext.gp_regs[VKI_PT_CCR],
333 &tst->arch.vex );
334
335 tst->arch.vex.guest_LR = frame->uc.uc_mcontext.gp_regs[VKI_PT_LNK];
336 tst->arch.vex.guest_CTR = frame->uc.uc_mcontext.gp_regs[VKI_PT_CTR];
337 LibVEX_GuestPPC64_put_XER( frame->uc.uc_mcontext.gp_regs[VKI_PT_XER],
338 &tst->arch.vex );
339
340 tst->arch.vex_shadow1 = priv->vex_shadow1;
341 tst->arch.vex_shadow2 = priv->vex_shadow2;
342
343 VG_TRACK(die_mem_stack_signal, sp, frame_size);
344
345 if (VG_(clo_trace_signals))
346 VG_(message)(Vg_DebugMsg,
347 "vg_pop_signal_frame (thread %d): isRT=%d "
348 "valid magic; EIP=%#llx\n",
349 tid, has_siginfo, tst->arch.vex.guest_CIA);
350
351 /* tell the tools */
352 VG_TRACK( post_deliver_signal, tid, sigNo );
353 }
354
355 #endif // defined(VGP_ppc64be_linux) || defined(VGP_ppc64le_linux)
356
357 /*--------------------------------------------------------------------*/
358 /*--- end ---*/
359 /*--------------------------------------------------------------------*/
360