1 /*
2 * Copyright (C) 2003 PathScale, Inc.
3 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
5 */
6
7
8 #include <linux/personality.h>
9 #include <linux/ptrace.h>
10 #include <linux/kernel.h>
11 #include <linux/syscalls.h>
12 #include <asm/unistd.h>
13 #include <linux/uaccess.h>
14 #include <asm/ucontext.h>
15 #include <frame_kern.h>
16 #include <registers.h>
17 #include <skas.h>
18
19 #include <linux/regset.h>
20 #include <asm/sigframe.h>
21
22 #ifdef CONFIG_X86_32
23 struct _xstate_64 {
24 struct _fpstate_64 fpstate;
25 struct _header xstate_hdr;
26 struct _ymmh_state ymmh;
27 /* New processor state extensions go here: */
28 };
29 #else
30 #define _xstate_64 _xstate
31 #endif
32
copy_sc_from_user(struct pt_regs * regs,struct sigcontext __user * from)33 static int copy_sc_from_user(struct pt_regs *regs,
34 struct sigcontext __user *from)
35 {
36 struct _xstate_64 __user *from_fp64;
37 struct sigcontext sc;
38 int err;
39
40 /* Always make any pending restarted system calls return -EINTR */
41 current->restart_block.fn = do_no_restart_syscall;
42
43 err = copy_from_user(&sc, from, sizeof(sc));
44 if (err)
45 return err;
46
47 #define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
48
49 #ifdef CONFIG_X86_32
50 GETREG(GS, gs);
51 GETREG(FS, fs);
52 GETREG(ES, es);
53 GETREG(DS, ds);
54 #endif
55 GETREG(DI, di);
56 GETREG(SI, si);
57 GETREG(BP, bp);
58 GETREG(SP, sp);
59 GETREG(BX, bx);
60 GETREG(DX, dx);
61 GETREG(CX, cx);
62 GETREG(AX, ax);
63 GETREG(IP, ip);
64
65 #ifdef CONFIG_X86_64
66 GETREG(R8, r8);
67 GETREG(R9, r9);
68 GETREG(R10, r10);
69 GETREG(R11, r11);
70 GETREG(R12, r12);
71 GETREG(R13, r13);
72 GETREG(R14, r14);
73 GETREG(R15, r15);
74 #endif
75
76 GETREG(CS, cs);
77 GETREG(EFLAGS, flags);
78 #ifdef CONFIG_X86_32
79 GETREG(SS, ss);
80 #endif
81
82 #undef GETREG
83
84 #ifdef CONFIG_X86_32
85 from_fp64 = ((void __user *)sc.fpstate) +
86 offsetof(struct _fpstate_32, _fxsr_env);
87 #else
88 from_fp64 = (void __user *)sc.fpstate;
89 #endif
90
91 err = copy_from_user(regs->regs.fp, from_fp64, host_fp_size);
92 if (err)
93 return 1;
94
95 #ifdef CONFIG_X86_32
96 /* Data is duplicated and this copy is the important one */
97 err = copy_regset_from_user(current,
98 task_user_regset_view(current),
99 REGSET_FP_LEGACY, 0,
100 sizeof(struct user_i387_struct),
101 (void __user *)sc.fpstate);
102 if (err < 0)
103 return err;
104 #endif
105
106 return 0;
107 }
108
copy_sc_to_user(struct sigcontext __user * to,struct _xstate __user * to_fp,struct pt_regs * regs,unsigned long mask)109 static int copy_sc_to_user(struct sigcontext __user *to,
110 struct _xstate __user *to_fp, struct pt_regs *regs,
111 unsigned long mask)
112 {
113 struct _xstate_64 __user *to_fp64;
114 struct sigcontext sc;
115 struct faultinfo * fi = ¤t->thread.arch.faultinfo;
116 int err;
117 memset(&sc, 0, sizeof(struct sigcontext));
118
119 #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
120
121 #ifdef CONFIG_X86_32
122 PUTREG(GS, gs);
123 PUTREG(FS, fs);
124 PUTREG(ES, es);
125 PUTREG(DS, ds);
126 #endif
127 PUTREG(DI, di);
128 PUTREG(SI, si);
129 PUTREG(BP, bp);
130 PUTREG(SP, sp);
131 PUTREG(BX, bx);
132 PUTREG(DX, dx);
133 PUTREG(CX, cx);
134 PUTREG(AX, ax);
135 #ifdef CONFIG_X86_64
136 PUTREG(R8, r8);
137 PUTREG(R9, r9);
138 PUTREG(R10, r10);
139 PUTREG(R11, r11);
140 PUTREG(R12, r12);
141 PUTREG(R13, r13);
142 PUTREG(R14, r14);
143 PUTREG(R15, r15);
144 #endif
145
146 sc.cr2 = fi->cr2;
147 sc.err = fi->error_code;
148 sc.trapno = fi->trap_no;
149 PUTREG(IP, ip);
150 PUTREG(CS, cs);
151 PUTREG(EFLAGS, flags);
152 #ifdef CONFIG_X86_32
153 PUTREG(SP, sp_at_signal);
154 PUTREG(SS, ss);
155 #endif
156 #undef PUTREG
157 sc.oldmask = mask;
158 sc.fpstate = (unsigned long)to_fp;
159
160 err = copy_to_user(to, &sc, sizeof(struct sigcontext));
161 if (err)
162 return 1;
163
164 #ifdef CONFIG_X86_32
165 err = copy_regset_to_user(current,
166 task_user_regset_view(current),
167 REGSET_FP_LEGACY, 0,
168 sizeof(struct _fpstate_32), to_fp);
169 if (err < 0)
170 return err;
171
172 __put_user(X86_FXSR_MAGIC, &to_fp->fpstate.magic);
173
174 BUILD_BUG_ON(offsetof(struct _xstate, xstate_hdr) !=
175 offsetof(struct _xstate_64, xstate_hdr) +
176 offsetof(struct _fpstate_32, _fxsr_env));
177 to_fp64 = (void __user *)to_fp +
178 offsetof(struct _fpstate_32, _fxsr_env);
179 #else
180 to_fp64 = to_fp;
181 #endif /* CONFIG_X86_32 */
182
183 if (copy_to_user(to_fp64, regs->regs.fp, host_fp_size))
184 return 1;
185
186 /*
187 * Put magic/size values for userspace. We do not bother to verify them
188 * later on, however, userspace needs them should it try to read the
189 * XSTATE data. And ptrace does not fill in these parts.
190 */
191 BUILD_BUG_ON(sizeof(int) != FP_XSTATE_MAGIC2_SIZE);
192 #ifdef CONFIG_X86_32
193 __put_user(offsetof(struct _fpstate_32, _fxsr_env) +
194 host_fp_size + FP_XSTATE_MAGIC2_SIZE,
195 &to_fp64->fpstate.sw_reserved.extended_size);
196 #else
197 __put_user(host_fp_size + FP_XSTATE_MAGIC2_SIZE,
198 &to_fp64->fpstate.sw_reserved.extended_size);
199 #endif
200 __put_user(host_fp_size, &to_fp64->fpstate.sw_reserved.xstate_size);
201
202 __put_user(FP_XSTATE_MAGIC1, &to_fp64->fpstate.sw_reserved.magic1);
203 __put_user(FP_XSTATE_MAGIC2,
204 (int __user *)((void __user *)to_fp64 + host_fp_size));
205
206 return 0;
207 }
208
209 #ifdef CONFIG_X86_32
copy_ucontext_to_user(struct ucontext __user * uc,struct _xstate __user * fp,sigset_t * set,unsigned long sp)210 static int copy_ucontext_to_user(struct ucontext __user *uc,
211 struct _xstate __user *fp, sigset_t *set,
212 unsigned long sp)
213 {
214 int err = 0;
215
216 err |= __save_altstack(&uc->uc_stack, sp);
217 err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0);
218 err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
219 return err;
220 }
221
setup_signal_stack_sc(unsigned long stack_top,struct ksignal * ksig,struct pt_regs * regs,sigset_t * mask)222 int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
223 struct pt_regs *regs, sigset_t *mask)
224 {
225 size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
226 host_fp_size + FP_XSTATE_MAGIC2_SIZE;
227 struct sigframe __user *frame;
228 void __user *restorer;
229 int err = 0, sig = ksig->sig;
230 unsigned long fp_to;
231
232 /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
233 stack_top = ((stack_top + 4) & -16UL) - 4;
234 frame = (struct sigframe __user *) stack_top - 1;
235 if (!access_ok(frame, sizeof(*frame)))
236 return 1;
237
238 /* Add required space for math frame */
239 frame = (struct sigframe __user *)((unsigned long)frame - math_size);
240
241 restorer = frame->retcode;
242 if (ksig->ka.sa.sa_flags & SA_RESTORER)
243 restorer = ksig->ka.sa.sa_restorer;
244
245 err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
246 err |= __put_user(sig, &frame->sig);
247
248 fp_to = (unsigned long)frame + sizeof(*frame);
249
250 err |= copy_sc_to_user(&frame->sc,
251 (struct _xstate __user *)fp_to,
252 regs, mask->sig[0]);
253 if (_NSIG_WORDS > 1)
254 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
255 sizeof(frame->extramask));
256
257 /*
258 * This is popl %eax ; movl $,%eax ; int $0x80
259 *
260 * WE DO NOT USE IT ANY MORE! It's only left here for historical
261 * reasons and because gdb uses it as a signature to notice
262 * signal handler stack frames.
263 */
264 err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
265 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
266 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
267
268 if (err)
269 return err;
270
271 PT_REGS_SP(regs) = (unsigned long) frame;
272 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
273 PT_REGS_AX(regs) = (unsigned long) sig;
274 PT_REGS_DX(regs) = (unsigned long) 0;
275 PT_REGS_CX(regs) = (unsigned long) 0;
276 return 0;
277 }
278
setup_signal_stack_si(unsigned long stack_top,struct ksignal * ksig,struct pt_regs * regs,sigset_t * mask)279 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
280 struct pt_regs *regs, sigset_t *mask)
281 {
282 size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
283 host_fp_size + FP_XSTATE_MAGIC2_SIZE;
284 struct rt_sigframe __user *frame;
285 void __user *restorer;
286 int err = 0, sig = ksig->sig;
287 unsigned long fp_to;
288
289 stack_top &= -8UL;
290 frame = (struct rt_sigframe __user *) stack_top - 1;
291 if (!access_ok(frame, sizeof(*frame)))
292 return 1;
293
294 /* Add required space for math frame */
295 frame = (struct rt_sigframe __user *)((unsigned long)frame - math_size);
296
297 restorer = frame->retcode;
298 if (ksig->ka.sa.sa_flags & SA_RESTORER)
299 restorer = ksig->ka.sa.sa_restorer;
300
301 err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
302 err |= __put_user(sig, &frame->sig);
303 err |= __put_user(&frame->info, (void __user * __user *)&frame->pinfo);
304 err |= __put_user(&frame->uc, (void __user * __user *)&frame->puc);
305 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
306
307 fp_to = (unsigned long)frame + sizeof(*frame);
308
309 err |= copy_ucontext_to_user(&frame->uc, (struct _xstate __user *)fp_to,
310 mask, PT_REGS_SP(regs));
311
312 /*
313 * This is movl $,%eax ; int $0x80
314 *
315 * WE DO NOT USE IT ANY MORE! It's only left here for historical
316 * reasons and because gdb uses it as a signature to notice
317 * signal handler stack frames.
318 */
319 err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
320 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
321 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
322
323 if (err)
324 return err;
325
326 PT_REGS_SP(regs) = (unsigned long) frame;
327 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
328 PT_REGS_AX(regs) = (unsigned long) sig;
329 PT_REGS_DX(regs) = (unsigned long) &frame->info;
330 PT_REGS_CX(regs) = (unsigned long) &frame->uc;
331 return 0;
332 }
333
SYSCALL_DEFINE0(sigreturn)334 SYSCALL_DEFINE0(sigreturn)
335 {
336 unsigned long sp = PT_REGS_SP(¤t->thread.regs);
337 struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
338 sigset_t set;
339 struct sigcontext __user *sc = &frame->sc;
340 int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
341
342 if (copy_from_user(&set.sig[0], &sc->oldmask, sizeof(set.sig[0])) ||
343 copy_from_user(&set.sig[1], frame->extramask, sig_size))
344 goto segfault;
345
346 set_current_blocked(&set);
347
348 if (copy_sc_from_user(¤t->thread.regs, sc))
349 goto segfault;
350
351 /* Avoid ERESTART handling */
352 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
353 return PT_REGS_SYSCALL_RET(¤t->thread.regs);
354
355 segfault:
356 force_sig(SIGSEGV);
357 return 0;
358 }
359
360 #else
361
setup_signal_stack_si(unsigned long stack_top,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)362 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
363 struct pt_regs *regs, sigset_t *set)
364 {
365 unsigned long math_size = host_fp_size + FP_XSTATE_MAGIC2_SIZE;
366 struct rt_sigframe __user *frame;
367 int err = 0, sig = ksig->sig;
368 unsigned long fp_to;
369
370 frame = (struct rt_sigframe __user *)
371 round_down(stack_top - sizeof(struct rt_sigframe), 16);
372
373 /* Add required space for math frame */
374 frame = (struct rt_sigframe __user *)((unsigned long)frame - math_size);
375
376 /* Subtract 128 for a red zone and 8 for proper alignment */
377 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
378
379 if (!access_ok(frame, sizeof(*frame) + math_size))
380 goto out;
381
382 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
383 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
384 if (err)
385 goto out;
386 }
387
388 /* Create the ucontext. */
389 err |= __put_user(0, &frame->uc.uc_flags);
390 err |= __put_user(NULL, &frame->uc.uc_link);
391 err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
392
393 fp_to = (unsigned long)frame + sizeof(*frame);
394
395 err |= copy_sc_to_user(&frame->uc.uc_mcontext,
396 (struct _xstate __user *)fp_to,
397 regs, set->sig[0]);
398
399 err |= __put_user(fp_to, &frame->uc.uc_mcontext.fpstate);
400 if (sizeof(*set) == 16) {
401 err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
402 err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
403 }
404 else
405 err |= __copy_to_user(&frame->uc.uc_sigmask, set,
406 sizeof(*set));
407
408 /*
409 * Set up to return from userspace. If provided, use a stub
410 * already in userspace.
411 */
412 /* x86-64 should always use SA_RESTORER. */
413 if (ksig->ka.sa.sa_flags & SA_RESTORER)
414 err |= __put_user((void __user *)ksig->ka.sa.sa_restorer,
415 &frame->pretcode);
416 else
417 /* could use a vstub here */
418 return err;
419
420 if (err)
421 return err;
422
423 PT_REGS_SP(regs) = (unsigned long) frame;
424 PT_REGS_DI(regs) = sig;
425 /* In case the signal handler was declared without prototypes */
426 PT_REGS_AX(regs) = 0;
427
428 /*
429 * This also works for non SA_SIGINFO handlers because they expect the
430 * next argument after the signal number on the stack.
431 */
432 PT_REGS_SI(regs) = (unsigned long) &frame->info;
433 PT_REGS_DX(regs) = (unsigned long) &frame->uc;
434 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
435 out:
436 return err;
437 }
438 #endif
439
SYSCALL_DEFINE0(rt_sigreturn)440 SYSCALL_DEFINE0(rt_sigreturn)
441 {
442 unsigned long sp = PT_REGS_SP(¤t->thread.regs);
443 struct rt_sigframe __user *frame =
444 (struct rt_sigframe __user *)(sp - sizeof(long));
445 struct ucontext __user *uc = &frame->uc;
446 sigset_t set;
447
448 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
449 goto segfault;
450
451 set_current_blocked(&set);
452
453 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext))
454 goto segfault;
455
456 /* Avoid ERESTART handling */
457 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
458 return PT_REGS_SYSCALL_RET(¤t->thread.regs);
459
460 segfault:
461 force_sig(SIGSEGV);
462 return 0;
463 }
464