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) 2000-2017 Nicholas Nethercote
12 njn@valgrind.org
13 Copyright (C) 2004-2017 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 Bool on_altstack,
138 Addr sp_top_of_frame,
139 const vki_siginfo_t *siginfo,
140 const struct vki_ucontext *siguc,
141 void *handler,
142 UInt flags,
143 const vki_sigset_t *mask,
144 void *restorer )
145 {
146 struct vg_sig_private* priv;
147 Addr sp;
148 ThreadState* tst;
149 Int sigNo = siginfo->si_signo;
150 /* Addr faultaddr; */ /* UNUSED */
151 struct rt_sigframe* frame;
152
153 /* Stack must be 16-byte aligned */
154 vg_assert(VG_IS_16_ALIGNED(sizeof(struct vg_sig_private)));
155 vg_assert(VG_IS_16_ALIGNED(sizeof(struct rt_sigframe)));
156
157 sp_top_of_frame &= ~0xf;
158 sp = sp_top_of_frame - sizeof(struct rt_sigframe);
159
160 tst = VG_(get_ThreadState)(tid);
161 if (! ML_(sf_maybe_extend_stack)(tst, sp, sp_top_of_frame - sp, flags))
162 return;
163
164 vg_assert(VG_IS_16_ALIGNED(sp));
165
166 frame = (struct rt_sigframe *) sp;
167
168 /* clear it (conservatively) */
169 VG_(memset)(frame, 0, sizeof(*frame));
170
171 /////////
172 frame->pinfo = &frame->info;
173 frame->puc = &frame->uc;
174
175 frame->uc.uc_flags = 0;
176 frame->uc.uc_link = 0;
177 /////////
178
179 /* Set up the stack chain pointer */
180 VG_TRACK( pre_mem_write, Vg_CoreSignal, tid, "signal handler frame",
181 sp, sizeof(UWord) );
182 *(Addr *)sp = tst->arch.vex.guest_GPR1;
183 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
184 sp, sizeof(UWord) );
185
186 /* UNUSED:
187 faultaddr = (Addr)siginfo->_sifields._sigfault._addr;
188 if (sigNo == VKI_SIGILL && siginfo->si_code > 0)
189 faultaddr = tst->arch.vex.guest_CIA;
190 */
191
192 VG_(memcpy)(&frame->info, siginfo, sizeof(*siginfo));
193 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
194 (Addr)&frame->info, sizeof(frame->info) );
195
196 frame->uc.uc_flags = 0;
197 frame->uc.uc_link = 0;
198 frame->uc.uc_stack = tst->altstack;
199 frame->uc.uc_sigmask = tst->sig_mask;
200 VG_TRACK( post_mem_write, Vg_CoreSignal, tid,
201 (Addr)(&frame->uc), sizeof(frame->uc) );
202
203 # define DO(gpr) frame->uc.uc_mcontext.gp_regs[VKI_PT_R0+gpr] \
204 = tst->arch.vex.guest_GPR##gpr
205 DO(0); DO(1); DO(2); DO(3); DO(4); DO(5); DO(6); DO(7);
206 DO(8); DO(9); DO(10); DO(11); DO(12); DO(13); DO(14); DO(15);
207 DO(16); DO(17); DO(18); DO(19); DO(20); DO(21); DO(22); DO(23);
208 DO(24); DO(25); DO(26); DO(27); DO(28); DO(29); DO(30); DO(31);
209 # undef DO
210
211 frame->uc.uc_mcontext.gp_regs[VKI_PT_NIP] = tst->arch.vex.guest_CIA;
212 #ifdef VGP_ppc64le_linux
213 frame->uc.uc_mcontext.gp_regs[VKI_PT_MSR] = 0xf033; /* pretty arbitrary */
214 #else
215 frame->uc.uc_mcontext.gp_regs[VKI_PT_MSR] = 0xf032; /* pretty arbitrary */
216 #endif
217 frame->uc.uc_mcontext.gp_regs[VKI_PT_ORIG_R3] = tst->arch.vex.guest_GPR3;
218 frame->uc.uc_mcontext.gp_regs[VKI_PT_CTR] = tst->arch.vex.guest_CTR;
219 frame->uc.uc_mcontext.gp_regs[VKI_PT_LNK] = tst->arch.vex.guest_LR;
220 frame->uc.uc_mcontext.gp_regs[VKI_PT_XER] = LibVEX_GuestPPC64_get_XER(
221 &tst->arch.vex);
222 frame->uc.uc_mcontext.gp_regs[VKI_PT_CCR] = LibVEX_GuestPPC64_get_CR(
223 &tst->arch.vex);
224 //mc->mc_gregs[VKI_PT_MQ] = 0;
225 //mc->mc_gregs[VKI_PT_TRAP] = 0;
226 //mc->mc_gregs[VKI_PT_DAR] = fault_addr;
227 //mc->mc_gregs[VKI_PT_DSISR] = 0;
228 //mc->mc_gregs[VKI_PT_RESULT] = 0;
229
230 /* XXX should do FP and vector regs */
231
232 /* set up signal return trampoline */
233 /* NB. 5 Sept 07. mc->mc_pad[0..1] used to contain a the code to
234 which the signal handler returns, and it just did sys_sigreturn
235 or sys_rt_sigreturn. But this doesn't work if the stack is
236 non-executable, and it isn't consistent with the x86-linux and
237 amd64-linux scheme for removing the stack frame. So instead be
238 consistent and use a stub in m_trampoline. Then it doesn't
239 matter whether or not the (guest) stack is executable. This
240 fixes #149519 and #145837. */
241 frame->tramp[0] = 0; /* invalid */
242 frame->tramp[1] = 0; /* invalid */
243 VG_TRACK(post_mem_write, Vg_CoreSignal, tst->tid,
244 (Addr)&frame->tramp, sizeof(frame->tramp));
245
246 /* invalidate any translation of this area */
247 VG_(discard_translations)( (Addr)&frame->tramp[0],
248 sizeof(frame->tramp), "stack_mcontext" );
249
250 /* set the signal handler to return to the trampoline */
251 SET_SIGNAL_LR(tst, (Addr)&VG_(ppc64_linux_SUBST_FOR_rt_sigreturn));
252
253 /* Stack pointer for the handler .. (note, back chain set
254 earlier) */
255 SET_SIGNAL_GPR(tid, 1, sp);
256
257 /* Args for the handler .. */
258 SET_SIGNAL_GPR(tid, 3, sigNo);
259 SET_SIGNAL_GPR(tid, 4, (Addr) &frame->info);
260 SET_SIGNAL_GPR(tid, 5, (Addr) &frame->uc);
261 /* the kernel sets this, though it doesn't seem to be in the ABI */
262 SET_SIGNAL_GPR(tid, 6, (Addr) &frame->info);
263
264 /* Handler is in fact a standard ppc64-linux function descriptor,
265 so extract the function entry point and also the toc ptr to use. */
266 #if defined(VGP_ppc64be_linux)
267 SET_SIGNAL_GPR(tid, 2, (Addr) ((ULong*)handler)[1]);
268 tst->arch.vex.guest_CIA = (Addr) ((ULong*)handler)[0];
269 #else
270 SET_SIGNAL_GPR(tid, 12, (Addr) handler);
271 tst->arch.vex.guest_CIA = (Addr) handler;
272 #endif
273 priv = &frame->priv;
274 priv->magicPI = 0x31415927;
275 priv->sigNo_private = sigNo;
276 priv->vex_shadow1 = tst->arch.vex_shadow1;
277 priv->vex_shadow2 = tst->arch.vex_shadow2;
278
279 if (0)
280 VG_(printf)("pushed signal frame; %%R1 now = %#lx, "
281 "next %%CIA = %#llx, status=%d\n",
282 sp, tst->arch.vex.guest_CIA, (Int)tst->status);
283 }
284
285
286 /*------------------------------------------------------------*/
287 /*--- Destroying signal frames ---*/
288 /*------------------------------------------------------------*/
289
290 /* EXPORTED */
VG_(sigframe_destroy)291 void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
292 {
293 ThreadState *tst;
294 struct vg_sig_private *priv;
295 Addr sp;
296 UInt frame_size;
297 struct rt_sigframe *frame;
298 Int sigNo;
299 Bool has_siginfo = isRT;
300
301 vg_assert(VG_(is_valid_tid)(tid));
302 tst = VG_(get_ThreadState)(tid);
303
304 /* Check that the stack frame looks valid */
305 sp = tst->arch.vex.guest_GPR1;
306 vg_assert(VG_IS_16_ALIGNED(sp));
307 /* JRS 17 Nov 05: This code used to check that *sp -- which should
308 have been set by the stwu at the start of the handler -- points
309 to just above the frame (ie, the previous frame). However, that
310 isn't valid when delivering signals on alt stacks. So I removed
311 it. The frame is still sanity-checked using the priv->magicPI
312 field. */
313
314 frame = (struct rt_sigframe *)sp;
315 frame_size = sizeof(*frame);
316 priv = &frame->priv;
317 vg_assert(priv->magicPI == 0x31415927);
318 tst->sig_mask = frame->uc.uc_sigmask;
319 tst->tmp_sig_mask = tst->sig_mask;
320
321 sigNo = priv->sigNo_private;
322
323 # define DO(gpr) tst->arch.vex.guest_GPR##gpr \
324 = frame->uc.uc_mcontext.gp_regs[VKI_PT_R0+gpr]
325 DO(0); DO(1); DO(2); DO(3); DO(4); DO(5); DO(6); DO(7);
326 DO(8); DO(9); DO(10); DO(11); DO(12); DO(13); DO(14); DO(15);
327 DO(16); DO(17); DO(18); DO(19); DO(20); DO(21); DO(22); DO(23);
328 DO(24); DO(25); DO(26); DO(27); DO(28); DO(29); DO(30); DO(31);
329 # undef DO
330
331 tst->arch.vex.guest_CIA = frame->uc.uc_mcontext.gp_regs[VKI_PT_NIP];
332
333 LibVEX_GuestPPC64_put_CR( frame->uc.uc_mcontext.gp_regs[VKI_PT_CCR],
334 &tst->arch.vex );
335
336 tst->arch.vex.guest_LR = frame->uc.uc_mcontext.gp_regs[VKI_PT_LNK];
337 tst->arch.vex.guest_CTR = frame->uc.uc_mcontext.gp_regs[VKI_PT_CTR];
338 LibVEX_GuestPPC64_put_XER( frame->uc.uc_mcontext.gp_regs[VKI_PT_XER],
339 &tst->arch.vex );
340
341 tst->arch.vex_shadow1 = priv->vex_shadow1;
342 tst->arch.vex_shadow2 = priv->vex_shadow2;
343
344 VG_TRACK(die_mem_stack_signal, sp, frame_size);
345
346 if (VG_(clo_trace_signals))
347 VG_(message)(Vg_DebugMsg,
348 "vg_pop_signal_frame (thread %u): isRT=%d "
349 "valid magic; EIP=%#llx\n",
350 tid, has_siginfo, tst->arch.vex.guest_CIA);
351
352 /* tell the tools */
353 VG_TRACK( post_deliver_signal, tid, sigNo );
354 }
355
356 #endif // defined(VGP_ppc64be_linux) || defined(VGP_ppc64le_linux)
357
358 /*--------------------------------------------------------------------*/
359 /*--- end ---*/
360 /*--------------------------------------------------------------------*/
361