Redo RM9000 workaround which along with other DSP ASE changes was
[linux-2.6] / arch / mips / kernel / signal.c
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1991, 1992  Linus Torvalds
7  * Copyright (C) 1994 - 2000  Ralf Baechle
8  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9  */
10 #include <linux/config.h>
11 #include <linux/cache.h>
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/personality.h>
15 #include <linux/smp.h>
16 #include <linux/smp_lock.h>
17 #include <linux/kernel.h>
18 #include <linux/signal.h>
19 #include <linux/errno.h>
20 #include <linux/wait.h>
21 #include <linux/ptrace.h>
22 #include <linux/unistd.h>
23 #include <linux/compiler.h>
24
25 #include <asm/abi.h>
26 #include <asm/asm.h>
27 #include <linux/bitops.h>
28 #include <asm/cacheflush.h>
29 #include <asm/fpu.h>
30 #include <asm/sim.h>
31 #include <asm/uaccess.h>
32 #include <asm/ucontext.h>
33 #include <asm/cpu-features.h>
34 #include <asm/war.h>
35
36 #include "signal-common.h"
37
38 #define DEBUG_SIG 0
39
40 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
41
42 int do_signal(sigset_t *oldset, struct pt_regs *regs);
43
44 /*
45  * Atomically swap in the new signal mask, and wait for a signal.
46  */
47
48 #ifdef CONFIG_TRAD_SIGNALS
49 save_static_function(sys_sigsuspend);
50 __attribute_used__ noinline static int
51 _sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
52 {
53         sigset_t saveset, newset;
54         sigset_t __user *uset;
55
56         uset = (sigset_t __user *) regs.regs[4];
57         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
58                 return -EFAULT;
59         sigdelsetmask(&newset, ~_BLOCKABLE);
60
61         spin_lock_irq(&current->sighand->siglock);
62         saveset = current->blocked;
63         current->blocked = newset;
64         recalc_sigpending();
65         spin_unlock_irq(&current->sighand->siglock);
66
67         regs.regs[2] = EINTR;
68         regs.regs[7] = 1;
69         while (1) {
70                 current->state = TASK_INTERRUPTIBLE;
71                 schedule();
72                 if (do_signal(&saveset, &regs))
73                         return -EINTR;
74         }
75 }
76 #endif
77
78 save_static_function(sys_rt_sigsuspend);
79 __attribute_used__ noinline static int
80 _sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
81 {
82         sigset_t saveset, newset;
83         sigset_t __user *unewset;
84         size_t sigsetsize;
85
86         /* XXX Don't preclude handling different sized sigset_t's.  */
87         sigsetsize = regs.regs[5];
88         if (sigsetsize != sizeof(sigset_t))
89                 return -EINVAL;
90
91         unewset = (sigset_t __user *) regs.regs[4];
92         if (copy_from_user(&newset, unewset, sizeof(newset)))
93                 return -EFAULT;
94         sigdelsetmask(&newset, ~_BLOCKABLE);
95
96         spin_lock_irq(&current->sighand->siglock);
97         saveset = current->blocked;
98         current->blocked = newset;
99         recalc_sigpending();
100         spin_unlock_irq(&current->sighand->siglock);
101
102         regs.regs[2] = EINTR;
103         regs.regs[7] = 1;
104         while (1) {
105                 current->state = TASK_INTERRUPTIBLE;
106                 schedule();
107                 if (do_signal(&saveset, &regs))
108                         return -EINTR;
109         }
110 }
111
112 #ifdef CONFIG_TRAD_SIGNALS
113 asmlinkage int sys_sigaction(int sig, const struct sigaction *act,
114         struct sigaction *oact)
115 {
116         struct k_sigaction new_ka, old_ka;
117         int ret;
118         int err = 0;
119
120         if (act) {
121                 old_sigset_t mask;
122
123                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
124                         return -EFAULT;
125                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
126                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
127                 err |= __get_user(mask, &act->sa_mask.sig[0]);
128                 if (err)
129                         return -EFAULT;
130
131                 siginitset(&new_ka.sa.sa_mask, mask);
132         }
133
134         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
135
136         if (!ret && oact) {
137                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
138                         return -EFAULT;
139                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
140                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
141                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
142                 err |= __put_user(0, &oact->sa_mask.sig[1]);
143                 err |= __put_user(0, &oact->sa_mask.sig[2]);
144                 err |= __put_user(0, &oact->sa_mask.sig[3]);
145                 if (err)
146                         return -EFAULT;
147         }
148
149         return ret;
150 }
151 #endif
152
153 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
154 {
155         const stack_t __user *uss = (const stack_t __user *) regs.regs[4];
156         stack_t __user *uoss = (stack_t __user *) regs.regs[5];
157         unsigned long usp = regs.regs[29];
158
159         return do_sigaltstack(uss, uoss, usp);
160 }
161
162 /*
163  * Horribly complicated - with the bloody RM9000 workarounds enabled
164  * the signal trampolines is moving to the end of the structure so we can
165  * increase the alignment without breaking software compatibility.
166  */
167 #ifdef CONFIG_TRAD_SIGNALS
168 struct sigframe {
169         u32 sf_ass[4];                  /* argument save space for o32 */
170 #if ICACHE_REFILLS_WORKAROUND_WAR
171         u32 sf_pad[2];
172 #else
173         u32 sf_code[2];                 /* signal trampoline */
174 #endif
175         struct sigcontext sf_sc;
176         sigset_t sf_mask;
177 #if ICACHE_REFILLS_WORKAROUND_WAR
178         u32 sf_code[8] ____cacheline_aligned;   /* signal trampoline */
179 #endif
180 };
181 #endif
182
183 struct rt_sigframe {
184         u32 rs_ass[4];                  /* argument save space for o32 */
185 #if ICACHE_REFILLS_WORKAROUND_WAR
186         u32 rs_pad[2];
187 #else
188         u32 rs_code[2];                 /* signal trampoline */
189 #endif
190         struct siginfo rs_info;
191         struct ucontext rs_uc;
192 #if ICACHE_REFILLS_WORKAROUND_WAR
193         u32 rs_code[8] ____cacheline_aligned;   /* signal trampoline */
194 #endif
195 };
196
197 #ifdef CONFIG_TRAD_SIGNALS
198 save_static_function(sys_sigreturn);
199 __attribute_used__ noinline static void
200 _sys_sigreturn(nabi_no_regargs struct pt_regs regs)
201 {
202         struct sigframe *frame;
203         sigset_t blocked;
204
205         frame = (struct sigframe *) regs.regs[29];
206         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
207                 goto badframe;
208         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
209                 goto badframe;
210
211         sigdelsetmask(&blocked, ~_BLOCKABLE);
212         spin_lock_irq(&current->sighand->siglock);
213         current->blocked = blocked;
214         recalc_sigpending();
215         spin_unlock_irq(&current->sighand->siglock);
216
217         if (restore_sigcontext(&regs, &frame->sf_sc))
218                 goto badframe;
219
220         /*
221          * Don't let your children do this ...
222          */
223         if (current_thread_info()->flags & TIF_SYSCALL_TRACE)
224                 do_syscall_trace(&regs, 1);
225         __asm__ __volatile__(
226                 "move\t$29, %0\n\t"
227                 "j\tsyscall_exit"
228                 :/* no outputs */
229                 :"r" (&regs));
230         /* Unreached */
231
232 badframe:
233         force_sig(SIGSEGV, current);
234 }
235 #endif /* CONFIG_TRAD_SIGNALS */
236
237 save_static_function(sys_rt_sigreturn);
238 __attribute_used__ noinline static void
239 _sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
240 {
241         struct rt_sigframe *frame;
242         sigset_t set;
243         stack_t st;
244
245         frame = (struct rt_sigframe *) regs.regs[29];
246         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
247                 goto badframe;
248         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
249                 goto badframe;
250
251         sigdelsetmask(&set, ~_BLOCKABLE);
252         spin_lock_irq(&current->sighand->siglock);
253         current->blocked = set;
254         recalc_sigpending();
255         spin_unlock_irq(&current->sighand->siglock);
256
257         if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
258                 goto badframe;
259
260         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
261                 goto badframe;
262         /* It is more difficult to avoid calling this function than to
263            call it and ignore errors.  */
264         do_sigaltstack(&st, NULL, regs.regs[29]);
265
266         /*
267          * Don't let your children do this ...
268          */
269         __asm__ __volatile__(
270                 "move\t$29, %0\n\t"
271                 "j\tsyscall_exit"
272                 :/* no outputs */
273                 :"r" (&regs));
274         /* Unreached */
275
276 badframe:
277         force_sig(SIGSEGV, current);
278 }
279
280 #ifdef CONFIG_TRAD_SIGNALS
281 void setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
282         int signr, sigset_t *set)
283 {
284         struct sigframe *frame;
285         int err = 0;
286
287         frame = get_sigframe(ka, regs, sizeof(*frame));
288         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
289                 goto give_sigsegv;
290
291         install_sigtramp(frame->sf_code, __NR_sigreturn);
292
293         err |= setup_sigcontext(regs, &frame->sf_sc);
294         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
295         if (err)
296                 goto give_sigsegv;
297
298         /*
299          * Arguments to signal handler:
300          *
301          *   a0 = signal number
302          *   a1 = 0 (should be cause)
303          *   a2 = pointer to struct sigcontext
304          *
305          * $25 and c0_epc point to the signal handler, $29 points to the
306          * struct sigframe.
307          */
308         regs->regs[ 4] = signr;
309         regs->regs[ 5] = 0;
310         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
311         regs->regs[29] = (unsigned long) frame;
312         regs->regs[31] = (unsigned long) frame->sf_code;
313         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
314
315 #if DEBUG_SIG
316         printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
317                current->comm, current->pid,
318                frame, regs->cp0_epc, frame->regs[31]);
319 #endif
320         return;
321
322 give_sigsegv:
323         force_sigsegv(signr, current);
324 }
325 #endif
326
327 void setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
328         int signr, sigset_t *set, siginfo_t *info)
329 {
330         struct rt_sigframe *frame;
331         int err = 0;
332
333         frame = get_sigframe(ka, regs, sizeof(*frame));
334         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
335                 goto give_sigsegv;
336
337         install_sigtramp(frame->rs_code, __NR_rt_sigreturn);
338
339         /* Create siginfo.  */
340         err |= copy_siginfo_to_user(&frame->rs_info, info);
341
342         /* Create the ucontext.  */
343         err |= __put_user(0, &frame->rs_uc.uc_flags);
344         err |= __put_user(0, &frame->rs_uc.uc_link);
345         err |= __put_user((void *)current->sas_ss_sp,
346                           &frame->rs_uc.uc_stack.ss_sp);
347         err |= __put_user(sas_ss_flags(regs->regs[29]),
348                           &frame->rs_uc.uc_stack.ss_flags);
349         err |= __put_user(current->sas_ss_size,
350                           &frame->rs_uc.uc_stack.ss_size);
351         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
352         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
353
354         if (err)
355                 goto give_sigsegv;
356
357         /*
358          * Arguments to signal handler:
359          *
360          *   a0 = signal number
361          *   a1 = 0 (should be cause)
362          *   a2 = pointer to ucontext
363          *
364          * $25 and c0_epc point to the signal handler, $29 points to
365          * the struct rt_sigframe.
366          */
367         regs->regs[ 4] = signr;
368         regs->regs[ 5] = (unsigned long) &frame->rs_info;
369         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
370         regs->regs[29] = (unsigned long) frame;
371         regs->regs[31] = (unsigned long) frame->rs_code;
372         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
373
374 #if DEBUG_SIG
375         printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
376                current->comm, current->pid,
377                frame, regs->cp0_epc, regs->regs[31]);
378 #endif
379         return;
380
381 give_sigsegv:
382         force_sigsegv(signr, current);
383 }
384
385 extern void setup_rt_frame_n32(struct k_sigaction * ka,
386         struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info);
387
388 static inline void handle_signal(unsigned long sig, siginfo_t *info,
389         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
390 {
391         switch(regs->regs[0]) {
392         case ERESTART_RESTARTBLOCK:
393         case ERESTARTNOHAND:
394                 regs->regs[2] = EINTR;
395                 break;
396         case ERESTARTSYS:
397                 if(!(ka->sa.sa_flags & SA_RESTART)) {
398                         regs->regs[2] = EINTR;
399                         break;
400                 }
401         /* fallthrough */
402         case ERESTARTNOINTR:            /* Userland will reload $v0.  */
403                 regs->regs[7] = regs->regs[26];
404                 regs->cp0_epc -= 8;
405         }
406
407         regs->regs[0] = 0;              /* Don't deal with this again.  */
408
409         if (sig_uses_siginfo(ka))
410                 current->thread.abi->setup_rt_frame(ka, regs, sig, oldset, info);
411         else
412                 current->thread.abi->setup_frame(ka, regs, sig, oldset);
413
414         spin_lock_irq(&current->sighand->siglock);
415         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
416         if (!(ka->sa.sa_flags & SA_NODEFER))
417                 sigaddset(&current->blocked,sig);
418         recalc_sigpending();
419         spin_unlock_irq(&current->sighand->siglock);
420 }
421
422 int do_signal(sigset_t *oldset, struct pt_regs *regs)
423 {
424         struct k_sigaction ka;
425         siginfo_t info;
426         int signr;
427
428         /*
429          * We want the common case to go fast, which is why we may in certain
430          * cases get here from kernel mode. Just return without doing anything
431          * if so.
432          */
433         if (!user_mode(regs))
434                 return 1;
435
436         if (try_to_freeze())
437                 goto no_signal;
438
439         if (!oldset)
440                 oldset = &current->blocked;
441
442         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
443         if (signr > 0) {
444                 handle_signal(signr, &info, &ka, oldset, regs);
445                 return 1;
446         }
447
448 no_signal:
449         /*
450          * Who's code doesn't conform to the restartable syscall convention
451          * dies here!!!  The li instruction, a single machine instruction,
452          * must directly be followed by the syscall instruction.
453          */
454         if (regs->regs[0]) {
455                 if (regs->regs[2] == ERESTARTNOHAND ||
456                     regs->regs[2] == ERESTARTSYS ||
457                     regs->regs[2] == ERESTARTNOINTR) {
458                         regs->regs[7] = regs->regs[26];
459                         regs->cp0_epc -= 8;
460                 }
461                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
462                         regs->regs[2] = __NR_restart_syscall;
463                         regs->regs[7] = regs->regs[26];
464                         regs->cp0_epc -= 4;
465                 }
466         }
467         return 0;
468 }
469
470 /*
471  * notification of userspace execution resumption
472  * - triggered by current->work.notify_resume
473  */
474 asmlinkage void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
475         __u32 thread_info_flags)
476 {
477         /* deal with pending signal delivery */
478         if (thread_info_flags & _TIF_SIGPENDING) {
479                 current->thread.abi->do_signal(oldset, regs);
480         }
481 }