UML: change sigcontext fields to match x86
[sfrench/cifs-2.6.git] / arch / um / sys-i386 / signal.c
1 /*
2  * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5
6 #include <linux/ptrace.h>
7 #include <asm/unistd.h>
8 #include <asm/uaccess.h>
9 #include <asm/ucontext.h>
10 #include "frame_kern.h"
11 #include "skas.h"
12
13 void copy_sc(struct uml_pt_regs *regs, void *from)
14 {
15         struct sigcontext *sc = from;
16
17         REGS_GS(regs->gp) = sc->gs;
18         REGS_FS(regs->gp) = sc->fs;
19         REGS_ES(regs->gp) = sc->es;
20         REGS_DS(regs->gp) = sc->ds;
21         REGS_EDI(regs->gp) = sc->di;
22         REGS_ESI(regs->gp) = sc->si;
23         REGS_EBP(regs->gp) = sc->bp;
24         REGS_SP(regs->gp) = sc->sp;
25         REGS_EBX(regs->gp) = sc->bx;
26         REGS_EDX(regs->gp) = sc->dx;
27         REGS_ECX(regs->gp) = sc->cx;
28         REGS_EAX(regs->gp) = sc->ax;
29         REGS_IP(regs->gp) = sc->ip;
30         REGS_CS(regs->gp) = sc->cs;
31         REGS_EFLAGS(regs->gp) = sc->flags;
32         REGS_SS(regs->gp) = sc->ss;
33 }
34
35 /*
36  * FPU tag word conversions.
37  */
38
39 static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
40 {
41         unsigned int tmp; /* to avoid 16 bit prefixes in the code */
42
43         /* Transform each pair of bits into 01 (valid) or 00 (empty) */
44         tmp = ~twd;
45         tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
46         /* and move the valid bits to the lower byte. */
47         tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
48         tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
49         tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
50         return tmp;
51 }
52
53 static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
54 {
55         struct _fpxreg *st = NULL;
56         unsigned long twd = (unsigned long) fxsave->twd;
57         unsigned long tag;
58         unsigned long ret = 0xffff0000;
59         int i;
60
61 #define FPREG_ADDR(f, n)        ((char *)&(f)->st_space + (n) * 16);
62
63         for (i = 0; i < 8; i++) {
64                 if (twd & 0x1) {
65                         st = (struct _fpxreg *) FPREG_ADDR(fxsave, i);
66
67                         switch (st->exponent & 0x7fff) {
68                         case 0x7fff:
69                                 tag = 2;                /* Special */
70                                 break;
71                         case 0x0000:
72                                 if ( !st->significand[0] &&
73                                      !st->significand[1] &&
74                                      !st->significand[2] &&
75                                      !st->significand[3] ) {
76                                         tag = 1;        /* Zero */
77                                 } else {
78                                         tag = 2;        /* Special */
79                                 }
80                                 break;
81                         default:
82                                 if (st->significand[3] & 0x8000) {
83                                         tag = 0;        /* Valid */
84                                 } else {
85                                         tag = 2;        /* Special */
86                                 }
87                                 break;
88                         }
89                 } else {
90                         tag = 3;                        /* Empty */
91                 }
92                 ret |= (tag << (2 * i));
93                 twd = twd >> 1;
94         }
95         return ret;
96 }
97
98 static int convert_fxsr_to_user(struct _fpstate __user *buf,
99                                 struct user_fxsr_struct *fxsave)
100 {
101         unsigned long env[7];
102         struct _fpreg __user *to;
103         struct _fpxreg *from;
104         int i;
105
106         env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
107         env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
108         env[2] = twd_fxsr_to_i387(fxsave);
109         env[3] = fxsave->fip;
110         env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
111         env[5] = fxsave->foo;
112         env[6] = fxsave->fos;
113
114         if (__copy_to_user(buf, env, 7 * sizeof(unsigned long)))
115                 return 1;
116
117         to = &buf->_st[0];
118         from = (struct _fpxreg *) &fxsave->st_space[0];
119         for (i = 0; i < 8; i++, to++, from++) {
120                 unsigned long __user *t = (unsigned long __user *)to;
121                 unsigned long *f = (unsigned long *)from;
122
123                 if (__put_user(*f, t) ||
124                                 __put_user(*(f + 1), t + 1) ||
125                                 __put_user(from->exponent, &to->exponent))
126                         return 1;
127         }
128         return 0;
129 }
130
131 static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave,
132                                   struct _fpstate __user *buf)
133 {
134         unsigned long env[7];
135         struct _fpxreg *to;
136         struct _fpreg __user *from;
137         int i;
138
139         if (copy_from_user( env, buf, 7 * sizeof(long)))
140                 return 1;
141
142         fxsave->cwd = (unsigned short)(env[0] & 0xffff);
143         fxsave->swd = (unsigned short)(env[1] & 0xffff);
144         fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
145         fxsave->fip = env[3];
146         fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
147         fxsave->fcs = (env[4] & 0xffff);
148         fxsave->foo = env[5];
149         fxsave->fos = env[6];
150
151         to = (struct _fpxreg *) &fxsave->st_space[0];
152         from = &buf->_st[0];
153         for (i = 0; i < 8; i++, to++, from++) {
154                 unsigned long *t = (unsigned long *)to;
155                 unsigned long __user *f = (unsigned long __user *)from;
156
157                 if (__get_user(*t, f) ||
158                     __get_user(*(t + 1), f + 1) ||
159                     __get_user(to->exponent, &from->exponent))
160                         return 1;
161         }
162         return 0;
163 }
164
165 extern int have_fpx_regs;
166
167 static int copy_sc_from_user(struct pt_regs *regs,
168                              struct sigcontext __user *from)
169 {
170         struct sigcontext sc;
171         int err;
172
173         err = copy_from_user(&sc, from, sizeof(sc));
174         if (err)
175                 return err;
176
177         copy_sc(&regs->regs, &sc);
178         if (have_fpx_regs) {
179                 struct user_fxsr_struct fpx;
180
181                 err = copy_from_user(&fpx, &sc.fpstate->_fxsr_env[0],
182                                      sizeof(struct user_fxsr_struct));
183                 if (err)
184                         return 1;
185
186                 err = convert_fxsr_from_user(&fpx, sc.fpstate);
187                 if (err)
188                         return 1;
189
190                 err = restore_fpx_registers(userspace_pid[current_thread->cpu],
191                                             (unsigned long *) &fpx);
192                 if (err < 0) {
193                         printk(KERN_ERR "copy_sc_from_user - "
194                                "restore_fpx_registers failed, errno = %d\n",
195                                -err);
196                         return 1;
197                 }
198         }
199         else {
200                 struct user_i387_struct fp;
201
202                 err = copy_from_user(&fp, sc.fpstate,
203                                      sizeof(struct user_i387_struct));
204                 if (err)
205                         return 1;
206
207                 err = restore_fp_registers(userspace_pid[current_thread->cpu],
208                                            (unsigned long *) &fp);
209                 if (err < 0) {
210                         printk(KERN_ERR "copy_sc_from_user - "
211                                "restore_fp_registers failed, errno = %d\n",
212                                -err);
213                         return 1;
214                 }
215         }
216
217         return 0;
218 }
219
220 static int copy_sc_to_user(struct sigcontext __user *to,
221                            struct _fpstate __user *to_fp, struct pt_regs *regs,
222                            unsigned long sp)
223 {
224         struct sigcontext sc;
225         struct faultinfo * fi = &current->thread.arch.faultinfo;
226         int err;
227
228         sc.gs = REGS_GS(regs->regs.gp);
229         sc.fs = REGS_FS(regs->regs.gp);
230         sc.es = REGS_ES(regs->regs.gp);
231         sc.ds = REGS_DS(regs->regs.gp);
232         sc.di = REGS_EDI(regs->regs.gp);
233         sc.si = REGS_ESI(regs->regs.gp);
234         sc.bp = REGS_EBP(regs->regs.gp);
235         sc.sp = sp;
236         sc.bx = REGS_EBX(regs->regs.gp);
237         sc.dx = REGS_EDX(regs->regs.gp);
238         sc.cx = REGS_ECX(regs->regs.gp);
239         sc.ax = REGS_EAX(regs->regs.gp);
240         sc.ip = REGS_IP(regs->regs.gp);
241         sc.cs = REGS_CS(regs->regs.gp);
242         sc.flags = REGS_EFLAGS(regs->regs.gp);
243         sc.sp_at_signal = regs->regs.gp[UESP];
244         sc.ss = regs->regs.gp[SS];
245         sc.cr2 = fi->cr2;
246         sc.err = fi->error_code;
247         sc.trapno = fi->trap_no;
248
249         to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
250         sc.fpstate = to_fp;
251
252         if (have_fpx_regs) {
253                 struct user_fxsr_struct fpx;
254
255                 err = save_fpx_registers(userspace_pid[current_thread->cpu],
256                                          (unsigned long *) &fpx);
257                 if (err < 0){
258                         printk(KERN_ERR "copy_sc_to_user - save_fpx_registers "
259                                "failed, errno = %d\n", err);
260                         return 1;
261                 }
262
263                 err = convert_fxsr_to_user(to_fp, &fpx);
264                 if (err)
265                         return 1;
266
267                 err |= __put_user(fpx.swd, &to_fp->status);
268                 err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic);
269                 if (err)
270                         return 1;
271
272                 if (copy_to_user(&to_fp->_fxsr_env[0], &fpx,
273                                  sizeof(struct user_fxsr_struct)))
274                         return 1;
275         }
276         else {
277                 struct user_i387_struct fp;
278
279                 err = save_fp_registers(userspace_pid[current_thread->cpu],
280                                         (unsigned long *) &fp);
281                 if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
282                         return 1;
283         }
284
285         return copy_to_user(to, &sc, sizeof(sc));
286 }
287
288 static int copy_ucontext_to_user(struct ucontext __user *uc,
289                                  struct _fpstate __user *fp, sigset_t *set,
290                                  unsigned long sp)
291 {
292         int err = 0;
293
294         err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
295         err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
296         err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
297         err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
298         err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
299         return err;
300 }
301
302 struct sigframe
303 {
304         char __user *pretcode;
305         int sig;
306         struct sigcontext sc;
307         struct _fpstate fpstate;
308         unsigned long extramask[_NSIG_WORDS-1];
309         char retcode[8];
310 };
311
312 struct rt_sigframe
313 {
314         char __user *pretcode;
315         int sig;
316         struct siginfo __user *pinfo;
317         void __user *puc;
318         struct siginfo info;
319         struct ucontext uc;
320         struct _fpstate fpstate;
321         char retcode[8];
322 };
323
324 int setup_signal_stack_sc(unsigned long stack_top, int sig,
325                           struct k_sigaction *ka, struct pt_regs *regs,
326                           sigset_t *mask)
327 {
328         struct sigframe __user *frame;
329         void __user *restorer;
330         unsigned long save_sp = PT_REGS_SP(regs);
331         int err = 0;
332
333         /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
334         stack_top = ((stack_top + 4) & -16UL) - 4;
335         frame = (struct sigframe __user *) stack_top - 1;
336         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
337                 return 1;
338
339         restorer = frame->retcode;
340         if (ka->sa.sa_flags & SA_RESTORER)
341                 restorer = ka->sa.sa_restorer;
342
343         /* Update SP now because the page fault handler refuses to extend
344          * the stack if the faulting address is too far below the current
345          * SP, which frame now certainly is.  If there's an error, the original
346          * value is restored on the way out.
347          * When writing the sigcontext to the stack, we have to write the
348          * original value, so that's passed to copy_sc_to_user, which does
349          * the right thing with it.
350          */
351         PT_REGS_SP(regs) = (unsigned long) frame;
352
353         err |= __put_user(restorer, &frame->pretcode);
354         err |= __put_user(sig, &frame->sig);
355         err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
356         err |= __put_user(mask->sig[0], &frame->sc.oldmask);
357         if (_NSIG_WORDS > 1)
358                 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
359                                       sizeof(frame->extramask));
360
361         /*
362          * This is popl %eax ; movl $,%eax ; int $0x80
363          *
364          * WE DO NOT USE IT ANY MORE! It's only left here for historical
365          * reasons and because gdb uses it as a signature to notice
366          * signal handler stack frames.
367          */
368         err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
369         err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
370         err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
371
372         if (err)
373                 goto err;
374
375         PT_REGS_SP(regs) = (unsigned long) frame;
376         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
377         PT_REGS_EAX(regs) = (unsigned long) sig;
378         PT_REGS_EDX(regs) = (unsigned long) 0;
379         PT_REGS_ECX(regs) = (unsigned long) 0;
380
381         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
382                 ptrace_notify(SIGTRAP);
383         return 0;
384
385 err:
386         PT_REGS_SP(regs) = save_sp;
387         return err;
388 }
389
390 int setup_signal_stack_si(unsigned long stack_top, int sig,
391                           struct k_sigaction *ka, struct pt_regs *regs,
392                           siginfo_t *info, sigset_t *mask)
393 {
394         struct rt_sigframe __user *frame;
395         void __user *restorer;
396         unsigned long save_sp = PT_REGS_SP(regs);
397         int err = 0;
398
399         stack_top &= -8UL;
400         frame = (struct rt_sigframe __user *) stack_top - 1;
401         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
402                 return 1;
403
404         restorer = frame->retcode;
405         if (ka->sa.sa_flags & SA_RESTORER)
406                 restorer = ka->sa.sa_restorer;
407
408         /* See comment above about why this is here */
409         PT_REGS_SP(regs) = (unsigned long) frame;
410
411         err |= __put_user(restorer, &frame->pretcode);
412         err |= __put_user(sig, &frame->sig);
413         err |= __put_user(&frame->info, &frame->pinfo);
414         err |= __put_user(&frame->uc, &frame->puc);
415         err |= copy_siginfo_to_user(&frame->info, info);
416         err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
417                                      save_sp);
418
419         /*
420          * This is movl $,%eax ; int $0x80
421          *
422          * WE DO NOT USE IT ANY MORE! It's only left here for historical
423          * reasons and because gdb uses it as a signature to notice
424          * signal handler stack frames.
425          */
426         err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
427         err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
428         err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
429
430         if (err)
431                 goto err;
432
433         PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
434         PT_REGS_EAX(regs) = (unsigned long) sig;
435         PT_REGS_EDX(regs) = (unsigned long) &frame->info;
436         PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
437
438         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
439                 ptrace_notify(SIGTRAP);
440         return 0;
441
442 err:
443         PT_REGS_SP(regs) = save_sp;
444         return err;
445 }
446
447 long sys_sigreturn(struct pt_regs regs)
448 {
449         unsigned long sp = PT_REGS_SP(&current->thread.regs);
450         struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
451         sigset_t set;
452         struct sigcontext __user *sc = &frame->sc;
453         unsigned long __user *oldmask = &sc->oldmask;
454         unsigned long __user *extramask = frame->extramask;
455         int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
456
457         if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
458             copy_from_user(&set.sig[1], extramask, sig_size))
459                 goto segfault;
460
461         sigdelsetmask(&set, ~_BLOCKABLE);
462
463         spin_lock_irq(&current->sighand->siglock);
464         current->blocked = set;
465         recalc_sigpending();
466         spin_unlock_irq(&current->sighand->siglock);
467
468         if (copy_sc_from_user(&current->thread.regs, sc))
469                 goto segfault;
470
471         /* Avoid ERESTART handling */
472         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
473         return PT_REGS_SYSCALL_RET(&current->thread.regs);
474
475  segfault:
476         force_sig(SIGSEGV, current);
477         return 0;
478 }
479
480 long sys_rt_sigreturn(struct pt_regs regs)
481 {
482         unsigned long sp = PT_REGS_SP(&current->thread.regs);
483         struct rt_sigframe __user *frame =
484                 (struct rt_sigframe __user *) (sp - 4);
485         sigset_t set;
486         struct ucontext __user *uc = &frame->uc;
487         int sig_size = _NSIG_WORDS * sizeof(unsigned long);
488
489         if (copy_from_user(&set, &uc->uc_sigmask, sig_size))
490                 goto segfault;
491
492         sigdelsetmask(&set, ~_BLOCKABLE);
493
494         spin_lock_irq(&current->sighand->siglock);
495         current->blocked = set;
496         recalc_sigpending();
497         spin_unlock_irq(&current->sighand->siglock);
498
499         if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
500                 goto segfault;
501
502         /* Avoid ERESTART handling */
503         PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
504         return PT_REGS_SYSCALL_RET(&current->thread.regs);
505
506  segfault:
507         force_sig(SIGSEGV, current);
508         return 0;
509 }