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 * Skip this if we do not have an XSTATE frame.
192 */
193 if (host_fp_size <= sizeof(to_fp64->fpstate))
194 return 0;
195
196 BUILD_BUG_ON(sizeof(int) != FP_XSTATE_MAGIC2_SIZE);
197 #ifdef CONFIG_X86_32
198 __put_user(offsetof(struct _fpstate_32, _fxsr_env) +
199 host_fp_size + FP_XSTATE_MAGIC2_SIZE,
200 &to_fp64->fpstate.sw_reserved.extended_size);
201 #else
202 __put_user(host_fp_size + FP_XSTATE_MAGIC2_SIZE,
203 &to_fp64->fpstate.sw_reserved.extended_size);
204 #endif
205 __put_user(host_fp_size, &to_fp64->fpstate.sw_reserved.xstate_size);
206
207 __put_user(FP_XSTATE_MAGIC1, &to_fp64->fpstate.sw_reserved.magic1);
208 __put_user(FP_XSTATE_MAGIC2,
209 (int __user *)((void __user *)to_fp64 + host_fp_size));
210
211 return 0;
212 }
213
214 #ifdef CONFIG_X86_32
copy_ucontext_to_user(struct ucontext __user * uc,struct _xstate __user * fp,sigset_t * set,unsigned long sp)215 static int copy_ucontext_to_user(struct ucontext __user *uc,
216 struct _xstate __user *fp, sigset_t *set,
217 unsigned long sp)
218 {
219 int err = 0;
220
221 err |= __save_altstack(&uc->uc_stack, sp);
222 err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0);
223 err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
224 return err;
225 }
226
setup_signal_stack_sc(unsigned long stack_top,struct ksignal * ksig,struct pt_regs * regs,sigset_t * mask)227 int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
228 struct pt_regs *regs, sigset_t *mask)
229 {
230 size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
231 host_fp_size + FP_XSTATE_MAGIC2_SIZE;
232 struct sigframe __user *frame;
233 void __user *restorer;
234 int err = 0, sig = ksig->sig;
235 unsigned long fp_to;
236
237 /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
238 stack_top = ((stack_top + 4) & -16UL) - 4;
239 frame = (struct sigframe __user *) stack_top - 1;
240 if (!access_ok(frame, sizeof(*frame)))
241 return 1;
242
243 /* Add required space for math frame */
244 frame = (struct sigframe __user *)((unsigned long)frame - math_size);
245
246 restorer = frame->retcode;
247 if (ksig->ka.sa.sa_flags & SA_RESTORER)
248 restorer = ksig->ka.sa.sa_restorer;
249
250 err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
251 err |= __put_user(sig, &frame->sig);
252
253 fp_to = (unsigned long)frame + sizeof(*frame);
254
255 err |= copy_sc_to_user(&frame->sc,
256 (struct _xstate __user *)fp_to,
257 regs, mask->sig[0]);
258 if (_NSIG_WORDS > 1)
259 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
260 sizeof(frame->extramask));
261
262 /*
263 * This is popl %eax ; movl $,%eax ; int $0x80
264 *
265 * WE DO NOT USE IT ANY MORE! It's only left here for historical
266 * reasons and because gdb uses it as a signature to notice
267 * signal handler stack frames.
268 */
269 err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
270 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
271 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
272
273 if (err)
274 return err;
275
276 PT_REGS_SP(regs) = (unsigned long) frame;
277 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
278 PT_REGS_AX(regs) = (unsigned long) sig;
279 PT_REGS_DX(regs) = (unsigned long) 0;
280 PT_REGS_CX(regs) = (unsigned long) 0;
281 return 0;
282 }
283
setup_signal_stack_si(unsigned long stack_top,struct ksignal * ksig,struct pt_regs * regs,sigset_t * mask)284 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
285 struct pt_regs *regs, sigset_t *mask)
286 {
287 size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
288 host_fp_size + FP_XSTATE_MAGIC2_SIZE;
289 struct rt_sigframe __user *frame;
290 void __user *restorer;
291 int err = 0, sig = ksig->sig;
292 unsigned long fp_to;
293
294 stack_top &= -8UL;
295 frame = (struct rt_sigframe __user *) stack_top - 1;
296 if (!access_ok(frame, sizeof(*frame)))
297 return 1;
298
299 /* Add required space for math frame */
300 frame = (struct rt_sigframe __user *)((unsigned long)frame - math_size);
301
302 restorer = frame->retcode;
303 if (ksig->ka.sa.sa_flags & SA_RESTORER)
304 restorer = ksig->ka.sa.sa_restorer;
305
306 err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
307 err |= __put_user(sig, &frame->sig);
308 err |= __put_user(&frame->info, (void __user * __user *)&frame->pinfo);
309 err |= __put_user(&frame->uc, (void __user * __user *)&frame->puc);
310 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
311
312 fp_to = (unsigned long)frame + sizeof(*frame);
313
314 err |= copy_ucontext_to_user(&frame->uc, (struct _xstate __user *)fp_to,
315 mask, PT_REGS_SP(regs));
316
317 /*
318 * This is movl $,%eax ; int $0x80
319 *
320 * WE DO NOT USE IT ANY MORE! It's only left here for historical
321 * reasons and because gdb uses it as a signature to notice
322 * signal handler stack frames.
323 */
324 err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
325 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
326 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
327
328 if (err)
329 return err;
330
331 PT_REGS_SP(regs) = (unsigned long) frame;
332 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
333 PT_REGS_AX(regs) = (unsigned long) sig;
334 PT_REGS_DX(regs) = (unsigned long) &frame->info;
335 PT_REGS_CX(regs) = (unsigned long) &frame->uc;
336 return 0;
337 }
338
SYSCALL_DEFINE0(sigreturn)339 SYSCALL_DEFINE0(sigreturn)
340 {
341 unsigned long sp = PT_REGS_SP(¤t->thread.regs);
342 struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
343 sigset_t set;
344 struct sigcontext __user *sc = &frame->sc;
345 int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
346
347 if (copy_from_user(&set.sig[0], &sc->oldmask, sizeof(set.sig[0])) ||
348 copy_from_user(&set.sig[1], frame->extramask, sig_size))
349 goto segfault;
350
351 set_current_blocked(&set);
352
353 if (copy_sc_from_user(¤t->thread.regs, sc))
354 goto segfault;
355
356 /* Avoid ERESTART handling */
357 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
358 return PT_REGS_SYSCALL_RET(¤t->thread.regs);
359
360 segfault:
361 force_sig(SIGSEGV);
362 return 0;
363 }
364
365 #else
366
setup_signal_stack_si(unsigned long stack_top,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)367 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
368 struct pt_regs *regs, sigset_t *set)
369 {
370 unsigned long math_size = host_fp_size + FP_XSTATE_MAGIC2_SIZE;
371 struct rt_sigframe __user *frame;
372 int err = 0, sig = ksig->sig;
373 unsigned long fp_to;
374
375 frame = (void __user *)stack_top - sizeof(struct rt_sigframe);
376
377 /* Add required space for math frame */
378 frame = (void __user *)((unsigned long)frame - math_size);
379
380 /* ABI requires 16 byte boundary alignment */
381 frame = (void __user *)round_down((unsigned long)frame, 16);
382
383 /* Subtract 128 for a red zone and 8 for proper alignment */
384 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
385
386 if (!access_ok(frame, sizeof(*frame) + math_size))
387 goto out;
388
389 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
390 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
391 if (err)
392 goto out;
393 }
394
395 /* Create the ucontext. */
396 err |= __put_user(0, &frame->uc.uc_flags);
397 err |= __put_user(NULL, &frame->uc.uc_link);
398 err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
399
400 fp_to = (unsigned long)frame + sizeof(*frame);
401
402 err |= copy_sc_to_user(&frame->uc.uc_mcontext,
403 (struct _xstate __user *)fp_to,
404 regs, set->sig[0]);
405
406 err |= __put_user(fp_to, &frame->uc.uc_mcontext.fpstate);
407 if (sizeof(*set) == 16) {
408 err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
409 err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
410 }
411 else
412 err |= __copy_to_user(&frame->uc.uc_sigmask, set,
413 sizeof(*set));
414
415 /*
416 * Set up to return from userspace. If provided, use a stub
417 * already in userspace.
418 */
419 /* x86-64 should always use SA_RESTORER. */
420 if (ksig->ka.sa.sa_flags & SA_RESTORER)
421 err |= __put_user((void __user *)ksig->ka.sa.sa_restorer,
422 &frame->pretcode);
423 else
424 /* could use a vstub here */
425 return err;
426
427 if (err)
428 return err;
429
430 PT_REGS_SP(regs) = (unsigned long) frame;
431 PT_REGS_DI(regs) = sig;
432 /* In case the signal handler was declared without prototypes */
433 PT_REGS_AX(regs) = 0;
434
435 /*
436 * This also works for non SA_SIGINFO handlers because they expect the
437 * next argument after the signal number on the stack.
438 */
439 PT_REGS_SI(regs) = (unsigned long) &frame->info;
440 PT_REGS_DX(regs) = (unsigned long) &frame->uc;
441 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
442 out:
443 return err;
444 }
445 #endif
446
SYSCALL_DEFINE0(rt_sigreturn)447 SYSCALL_DEFINE0(rt_sigreturn)
448 {
449 unsigned long sp = PT_REGS_SP(¤t->thread.regs);
450 struct rt_sigframe __user *frame =
451 (struct rt_sigframe __user *)(sp - sizeof(long));
452 struct ucontext __user *uc = &frame->uc;
453 sigset_t set;
454
455 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
456 goto segfault;
457
458 set_current_blocked(&set);
459
460 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext))
461 goto segfault;
462
463 /* Avoid ERESTART handling */
464 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
465 return PT_REGS_SYSCALL_RET(¤t->thread.regs);
466
467 segfault:
468 force_sig(SIGSEGV);
469 return 0;
470 }
471