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sparc32: Fix exit flag passed from traced sys_sigreturn
[linux-2.6/btrfs-unstable.git] / arch / sparc / kernel / signal_64.c
blob35923e8abd8234f8fe067c0ed4a5e6f49ee85cb8
1 /*
2 * arch/sparc64/kernel/signal.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
6 * Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
7 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
8 * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
9 */
10
11 #ifdef CONFIG_COMPAT
12 #include <linux/compat.h> /* for compat_old_sigset_t */
13 #endif
14 #include <linux/sched.h>
15 #include <linux/kernel.h>
16 #include <linux/signal.h>
17 #include <linux/errno.h>
18 #include <linux/wait.h>
19 #include <linux/ptrace.h>
20 #include <linux/tracehook.h>
21 #include <linux/unistd.h>
22 #include <linux/mm.h>
23 #include <linux/tty.h>
24 #include <linux/binfmts.h>
25 #include <linux/bitops.h>
26
27 #include <asm/uaccess.h>
28 #include <asm/ptrace.h>
29 #include <asm/pgtable.h>
30 #include <asm/fpumacro.h>
31 #include <asm/uctx.h>
32 #include <asm/siginfo.h>
33 #include <asm/visasm.h>
34 #include <asm/switch_to.h>
35 #include <asm/cacheflush.h>
36
37 #include "entry.h"
38 #include "systbls.h"
39 #include "sigutil.h"
40
41 /* {set, get}context() needed for 64-bit SparcLinux userland. */
42 asmlinkage void sparc64_set_context(struct pt_regs *regs)
43 {
44 struct ucontext __user *ucp = (struct ucontext __user *)
45 regs->u_regs[UREG_I0];
46 mc_gregset_t __user *grp;
47 unsigned long pc, npc, tstate;
48 unsigned long fp, i7;
49 unsigned char fenab;
50 int err;
51
52 flush_user_windows();
53 if (get_thread_wsaved() ||
54 (((unsigned long)ucp) & (sizeof(unsigned long)-1)) ||
55 (!__access_ok(ucp, sizeof(*ucp))))
56 goto do_sigsegv;
57 grp = &ucp->uc_mcontext.mc_gregs;
58 err = __get_user(pc, &((*grp)[MC_PC]));
59 err |= __get_user(npc, &((*grp)[MC_NPC]));
60 if (err || ((pc | npc) & 3))
61 goto do_sigsegv;
62 if (regs->u_regs[UREG_I1]) {
63 sigset_t set;
64
65 if (_NSIG_WORDS == 1) {
66 if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
67 goto do_sigsegv;
68 } else {
69 if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
70 goto do_sigsegv;
71 }
72 set_current_blocked(&set);
73 }
74 if (test_thread_flag(TIF_32BIT)) {
75 pc &= 0xffffffff;
76 npc &= 0xffffffff;
77 }
78 regs->tpc = pc;
79 regs->tnpc = npc;
80 err |= __get_user(regs->y, &((*grp)[MC_Y]));
81 err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
82 regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
83 regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
84 err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
85 err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
86 err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
87 err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
88 err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
89 err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
90
91 /* Skip %g7 as that's the thread register in userspace. */
92
93 err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
94 err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
95 err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
96 err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
97 err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
98 err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
99 err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
100 err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));
101
102 err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
103 err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
104 err |= __put_user(fp,
105 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
106 err |= __put_user(i7,
107 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
108
109 err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
110 if (fenab) {
111 unsigned long *fpregs = current_thread_info()->fpregs;
112 unsigned long fprs;
113
114 fprs_write(0);
115 err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
116 if (fprs & FPRS_DL)
117 err |= copy_from_user(fpregs,
118 &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
119 (sizeof(unsigned int) * 32));
120 if (fprs & FPRS_DU)
121 err |= copy_from_user(fpregs+16,
122 ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
123 (sizeof(unsigned int) * 32));
124 err |= __get_user(current_thread_info()->xfsr[0],
125 &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
126 err |= __get_user(current_thread_info()->gsr[0],
127 &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
128 regs->tstate &= ~TSTATE_PEF;
129 }
130 if (err)
131 goto do_sigsegv;
132
133 return;
134 do_sigsegv:
135 force_sig(SIGSEGV, current);
136 }
137
138 asmlinkage void sparc64_get_context(struct pt_regs *regs)
139 {
140 struct ucontext __user *ucp = (struct ucontext __user *)
141 regs->u_regs[UREG_I0];
142 mc_gregset_t __user *grp;
143 mcontext_t __user *mcp;
144 unsigned long fp, i7;
145 unsigned char fenab;
146 int err;
147
148 synchronize_user_stack();
149 if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
150 goto do_sigsegv;
151
152 #if 1
153 fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
154 #else
155 fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
156 #endif
157
158 mcp = &ucp->uc_mcontext;
159 grp = &mcp->mc_gregs;
160
161 /* Skip over the trap instruction, first. */
162 if (test_thread_flag(TIF_32BIT)) {
163 regs->tpc = (regs->tnpc & 0xffffffff);
164 regs->tnpc = (regs->tnpc + 4) & 0xffffffff;
165 } else {
166 regs->tpc = regs->tnpc;
167 regs->tnpc += 4;
168 }
169 err = 0;
170 if (_NSIG_WORDS == 1)
171 err |= __put_user(current->blocked.sig[0],
172 (unsigned long __user *)&ucp->uc_sigmask);
173 else
174 err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
175 sizeof(sigset_t));
176
177 err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
178 err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
179 err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
180 err |= __put_user(regs->y, &((*grp)[MC_Y]));
181 err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
182 err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
183 err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
184 err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
185 err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
186 err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
187 err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
188 err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
189 err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
190 err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
191 err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
192 err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
193 err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
194 err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
195 err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));
196
197 err |= __get_user(fp,
198 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
199 err |= __get_user(i7,
200 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
201 err |= __put_user(fp, &(mcp->mc_fp));
202 err |= __put_user(i7, &(mcp->mc_i7));
203
204 err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
205 if (fenab) {
206 unsigned long *fpregs = current_thread_info()->fpregs;
207 unsigned long fprs;
208
209 fprs = current_thread_info()->fpsaved[0];
210 if (fprs & FPRS_DL)
211 err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
212 (sizeof(unsigned int) * 32));
213 if (fprs & FPRS_DU)
214 err |= copy_to_user(
215 ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
216 (sizeof(unsigned int) * 32));
217 err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
218 err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
219 err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
220 }
221 if (err)
222 goto do_sigsegv;
223
224 return;
225 do_sigsegv:
226 force_sig(SIGSEGV, current);
227 }
228
229 struct rt_signal_frame {
230 struct sparc_stackf ss;
231 siginfo_t info;
232 struct pt_regs regs;
233 __siginfo_fpu_t __user *fpu_save;
234 stack_t stack;
235 sigset_t mask;
236 __siginfo_rwin_t *rwin_save;
237 };
238
239 void do_rt_sigreturn(struct pt_regs *regs)
240 {
241 struct rt_signal_frame __user *sf;
242 unsigned long tpc, tnpc, tstate;
243 __siginfo_fpu_t __user *fpu_save;
244 __siginfo_rwin_t __user *rwin_save;
245 sigset_t set;
246 int err;
247
248 /* Always make any pending restarted system calls return -EINTR */
249 current_thread_info()->restart_block.fn = do_no_restart_syscall;
250
251 synchronize_user_stack ();
252 sf = (struct rt_signal_frame __user *)
253 (regs->u_regs [UREG_FP] + STACK_BIAS);
254
255 /* 1. Make sure we are not getting garbage from the user */
256 if (((unsigned long) sf) & 3)
257 goto segv;
258
259 err = get_user(tpc, &sf->regs.tpc);
260 err |= __get_user(tnpc, &sf->regs.tnpc);
261 if (test_thread_flag(TIF_32BIT)) {
262 tpc &= 0xffffffff;
263 tnpc &= 0xffffffff;
264 }
265 err |= ((tpc | tnpc) & 3);
266
267 /* 2. Restore the state */
268 err |= __get_user(regs->y, &sf->regs.y);
269 err |= __get_user(tstate, &sf->regs.tstate);
270 err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
271
272 /* User can only change condition codes and %asi in %tstate. */
273 regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
274 regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
275
276 err |= __get_user(fpu_save, &sf->fpu_save);
277 if (!err && fpu_save)
278 err |= restore_fpu_state(regs, fpu_save);
279
280 err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
281 err |= restore_altstack(&sf->stack);
282 if (err)
283 goto segv;
284
285 err |= __get_user(rwin_save, &sf->rwin_save);
286 if (!err && rwin_save) {
287 if (restore_rwin_state(rwin_save))
288 goto segv;
289 }
290
291 regs->tpc = tpc;
292 regs->tnpc = tnpc;
293
294 /* Prevent syscall restart. */
295 pt_regs_clear_syscall(regs);
296
297 set_current_blocked(&set);
298 return;
299 segv:
300 force_sig(SIGSEGV, current);
301 }
302
303 /* Checks if the fp is valid */
304 static int invalid_frame_pointer(void __user *fp)
305 {
306 if (((unsigned long) fp) & 15)
307 return 1;
308 return 0;
309 }
310
311 static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
312 {
313 unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
314
315 /*
316 * If we are on the alternate signal stack and would overflow it, don't.
317 * Return an always-bogus address instead so we will die with SIGSEGV.
318 */
319 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
320 return (void __user *) -1L;
321
322 /* This is the X/Open sanctioned signal stack switching. */
323 sp = sigsp(sp, ksig) - framesize;
324
325 /* Always align the stack frame. This handles two cases. First,
326 * sigaltstack need not be mindful of platform specific stack
327 * alignment. Second, if we took this signal because the stack
328 * is not aligned properly, we'd like to take the signal cleanly
329 * and report that.
330 */
331 sp &= ~15UL;
332
333 return (void __user *) sp;
334 }
335
336 static inline int
337 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
338 {
339 struct rt_signal_frame __user *sf;
340 int wsaved, err, sf_size;
341 void __user *tail;
342
343 /* 1. Make sure everything is clean */
344 synchronize_user_stack();
345 save_and_clear_fpu();
346
347 wsaved = get_thread_wsaved();
348
349 sf_size = sizeof(struct rt_signal_frame);
350 if (current_thread_info()->fpsaved[0] & FPRS_FEF)
351 sf_size += sizeof(__siginfo_fpu_t);
352 if (wsaved)
353 sf_size += sizeof(__siginfo_rwin_t);
354 sf = (struct rt_signal_frame __user *)
355 get_sigframe(ksig, regs, sf_size);
356
357 if (invalid_frame_pointer (sf)) {
358 do_exit(SIGILL); /* won't return, actually */
359 return -EINVAL;
360 }
361
362 tail = (sf + 1);
363
364 /* 2. Save the current process state */
365 err = copy_to_user(&sf->regs, regs, sizeof (*regs));
366
367 if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
368 __siginfo_fpu_t __user *fpu_save = tail;
369 tail += sizeof(__siginfo_fpu_t);
370 err |= save_fpu_state(regs, fpu_save);
371 err |= __put_user((u64)fpu_save, &sf->fpu_save);
372 } else {
373 err |= __put_user(0, &sf->fpu_save);
374 }
375 if (wsaved) {
376 __siginfo_rwin_t __user *rwin_save = tail;
377 tail += sizeof(__siginfo_rwin_t);
378 err |= save_rwin_state(wsaved, rwin_save);
379 err |= __put_user((u64)rwin_save, &sf->rwin_save);
380 set_thread_wsaved(0);
381 } else {
382 err |= __put_user(0, &sf->rwin_save);
383 }
384
385 /* Setup sigaltstack */
386 err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
387
388 err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t));
389
390 if (!wsaved) {
391 err |= copy_in_user((u64 __user *)sf,
392 (u64 __user *)(regs->u_regs[UREG_FP] +
393 STACK_BIAS),
394 sizeof(struct reg_window));
395 } else {
396 struct reg_window *rp;
397
398 rp = &current_thread_info()->reg_window[wsaved - 1];
399 err |= copy_to_user(sf, rp, sizeof(struct reg_window));
400 }
401 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
402 err |= copy_siginfo_to_user(&sf->info, &ksig->info);
403 else {
404 err |= __put_user(ksig->sig, &sf->info.si_signo);
405 err |= __put_user(SI_NOINFO, &sf->info.si_code);
406 }
407 if (err)
408 return err;
409
410 /* 3. signal handler back-trampoline and parameters */
411 regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
412 regs->u_regs[UREG_I0] = ksig->sig;
413 regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
414
415 /* The sigcontext is passed in this way because of how it
416 * is defined in GLIBC's /usr/include/bits/sigcontext.h
417 * for sparc64. It includes the 128 bytes of siginfo_t.
418 */
419 regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
420
421 /* 5. signal handler */
422 regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
423 regs->tnpc = (regs->tpc + 4);
424 if (test_thread_flag(TIF_32BIT)) {
425 regs->tpc &= 0xffffffff;
426 regs->tnpc &= 0xffffffff;
427 }
428 /* 4. return to kernel instructions */
429 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
430 return 0;
431 }
432
433 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
434 struct sigaction *sa)
435 {
436 switch (regs->u_regs[UREG_I0]) {
437 case ERESTART_RESTARTBLOCK:
438 case ERESTARTNOHAND:
439 no_system_call_restart:
440 regs->u_regs[UREG_I0] = EINTR;
441 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
442 break;
443 case ERESTARTSYS:
444 if (!(sa->sa_flags & SA_RESTART))
445 goto no_system_call_restart;
446 /* fallthrough */
447 case ERESTARTNOINTR:
448 regs->u_regs[UREG_I0] = orig_i0;
449 regs->tpc -= 4;
450 regs->tnpc -= 4;
451 }
452 }
453
454 /* Note that 'init' is a special process: it doesn't get signals it doesn't
455 * want to handle. Thus you cannot kill init even with a SIGKILL even by
456 * mistake.
457 */
458 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
459 {
460 struct ksignal ksig;
461 int restart_syscall;
462 bool has_handler;
463
464 /* It's a lot of work and synchronization to add a new ptrace
465 * register for GDB to save and restore in order to get
466 * orig_i0 correct for syscall restarts when debugging.
467 *
468 * Although it should be the case that most of the global
469 * registers are volatile across a system call, glibc already
470 * depends upon that fact that we preserve them. So we can't
471 * just use any global register to save away the orig_i0 value.
472 *
473 * In particular %g2, %g3, %g4, and %g5 are all assumed to be
474 * preserved across a system call trap by various pieces of
475 * code in glibc.
476 *
477 * %g7 is used as the "thread register". %g6 is not used in
478 * any fixed manner. %g6 is used as a scratch register and
479 * a compiler temporary, but it's value is never used across
480 * a system call. Therefore %g6 is usable for orig_i0 storage.
481 */
482 if (pt_regs_is_syscall(regs) &&
483 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY)))
484 regs->u_regs[UREG_G6] = orig_i0;
485
486 #ifdef CONFIG_COMPAT
487 if (test_thread_flag(TIF_32BIT)) {
488 extern void do_signal32(struct pt_regs *);
489 do_signal32(regs);
490 return;
491 }
492 #endif
493
494 has_handler = get_signal(&ksig);
495
496 restart_syscall = 0;
497 if (pt_regs_is_syscall(regs) &&
498 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
499 restart_syscall = 1;
500 orig_i0 = regs->u_regs[UREG_G6];
501 }
502
503 if (has_handler) {
504 if (restart_syscall)
505 syscall_restart(orig_i0, regs, &ksig.ka.sa);
506 signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0);
507 } else {
508 if (restart_syscall) {
509 switch (regs->u_regs[UREG_I0]) {
510 case ERESTARTNOHAND:
511 case ERESTARTSYS:
512 case ERESTARTNOINTR:
513 /* replay the system call when we are done */
514 regs->u_regs[UREG_I0] = orig_i0;
515 regs->tpc -= 4;
516 regs->tnpc -= 4;
517 pt_regs_clear_syscall(regs);
518 case ERESTART_RESTARTBLOCK:
519 regs->u_regs[UREG_G1] = __NR_restart_syscall;
520 regs->tpc -= 4;
521 regs->tnpc -= 4;
522 pt_regs_clear_syscall(regs);
523 }
524 }
525 restore_saved_sigmask();
526 }
527 }
528
529 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
530 {
531 if (thread_info_flags & _TIF_SIGPENDING)
532 do_signal(regs, orig_i0);
533 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
534 clear_thread_flag(TIF_NOTIFY_RESUME);
535 tracehook_notify_resume(regs);
536 }
537 }
538
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