Commit | Line | Data |
---|---|---|
ac689eb7 JB |
1 | /* |
2 | * OpenRISC signal.c | |
3 | * | |
4 | * Linux architectural port borrowing liberally from similar works of | |
5 | * others. All original copyrights apply as per the original source | |
6 | * declaration. | |
7 | * | |
8 | * Modifications for the OpenRISC architecture: | |
9 | * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> | |
10 | * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version | |
15 | * 2 of the License, or (at your option) any later version. | |
16 | */ | |
17 | ||
18 | #include <linux/sched.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/smp.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/signal.h> | |
23 | #include <linux/errno.h> | |
24 | #include <linux/wait.h> | |
25 | #include <linux/ptrace.h> | |
26 | #include <linux/unistd.h> | |
27 | #include <linux/stddef.h> | |
28 | #include <linux/tracehook.h> | |
29 | ||
30 | #include <asm/processor.h> | |
31 | #include <asm/ucontext.h> | |
32 | #include <asm/uaccess.h> | |
33 | ||
34 | #define DEBUG_SIG 0 | |
35 | ||
36 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
37 | ||
38 | asmlinkage long | |
39 | _sys_sigaltstack(const stack_t *uss, stack_t *uoss, struct pt_regs *regs) | |
40 | { | |
41 | return do_sigaltstack(uss, uoss, regs->sp); | |
42 | } | |
43 | ||
44 | struct rt_sigframe { | |
45 | struct siginfo *pinfo; | |
46 | void *puc; | |
47 | struct siginfo info; | |
48 | struct ucontext uc; | |
49 | unsigned char retcode[16]; /* trampoline code */ | |
50 | }; | |
51 | ||
52 | static int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc) | |
53 | { | |
54 | unsigned int err = 0; | |
55 | unsigned long old_usp; | |
56 | ||
57 | /* Alwys make any pending restarted system call return -EINTR */ | |
58 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
59 | ||
60 | /* restore the regs from &sc->regs (same as sc, since regs is first) | |
61 | * (sc is already checked for VERIFY_READ since the sigframe was | |
62 | * checked in sys_sigreturn previously) | |
63 | */ | |
64 | ||
65 | if (__copy_from_user(regs, sc, sizeof(struct pt_regs))) | |
66 | goto badframe; | |
67 | ||
68 | /* make sure the SM-bit is cleared so user-mode cannot fool us */ | |
69 | regs->sr &= ~SPR_SR_SM; | |
70 | ||
71 | /* restore the old USP as it was before we stacked the sc etc. | |
72 | * (we cannot just pop the sigcontext since we aligned the sp and | |
73 | * stuff after pushing it) | |
74 | */ | |
75 | ||
76 | err |= __get_user(old_usp, &sc->usp); | |
77 | ||
78 | regs->sp = old_usp; | |
79 | ||
80 | /* TODO: the other ports use regs->orig_XX to disable syscall checks | |
81 | * after this completes, but we don't use that mechanism. maybe we can | |
82 | * use it now ? | |
83 | */ | |
84 | ||
85 | return err; | |
86 | ||
87 | badframe: | |
88 | return 1; | |
89 | } | |
90 | ||
91 | asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs) | |
92 | { | |
93 | struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp; | |
94 | sigset_t set; | |
95 | stack_t st; | |
96 | ||
97 | /* | |
98 | * Since we stacked the signal on a dword boundary, | |
99 | * then frame should be dword aligned here. If it's | |
100 | * not, then the user is trying to mess with us. | |
101 | */ | |
102 | if (((long)frame) & 3) | |
103 | goto badframe; | |
104 | ||
105 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
106 | goto badframe; | |
107 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
108 | goto badframe; | |
109 | ||
110 | sigdelsetmask(&set, ~_BLOCKABLE); | |
111 | spin_lock_irq(¤t->sighand->siglock); | |
112 | current->blocked = set; | |
113 | recalc_sigpending(); | |
114 | spin_unlock_irq(¤t->sighand->siglock); | |
115 | ||
116 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
117 | goto badframe; | |
118 | ||
119 | if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) | |
120 | goto badframe; | |
121 | /* It is more difficult to avoid calling this function than to | |
122 | call it and ignore errors. */ | |
123 | do_sigaltstack(&st, NULL, regs->sp); | |
124 | ||
125 | return regs->gpr[11]; | |
126 | ||
127 | badframe: | |
128 | force_sig(SIGSEGV, current); | |
129 | return 0; | |
130 | } | |
131 | ||
132 | /* | |
133 | * Set up a signal frame. | |
134 | */ | |
135 | ||
136 | static int setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs, | |
137 | unsigned long mask) | |
138 | { | |
139 | int err = 0; | |
140 | unsigned long usp = regs->sp; | |
141 | ||
142 | /* copy the regs. they are first in sc so we can use sc directly */ | |
143 | ||
144 | err |= __copy_to_user(sc, regs, sizeof(struct pt_regs)); | |
145 | ||
146 | /* then some other stuff */ | |
147 | ||
148 | err |= __put_user(mask, &sc->oldmask); | |
149 | ||
150 | err |= __put_user(usp, &sc->usp); | |
151 | ||
152 | return err; | |
153 | } | |
154 | ||
155 | static inline unsigned long align_sigframe(unsigned long sp) | |
156 | { | |
157 | return sp & ~3UL; | |
158 | } | |
159 | ||
160 | /* | |
161 | * Work out where the signal frame should go. It's either on the user stack | |
162 | * or the alternate stack. | |
163 | */ | |
164 | ||
165 | static inline void __user *get_sigframe(struct k_sigaction *ka, | |
166 | struct pt_regs *regs, size_t frame_size) | |
167 | { | |
168 | unsigned long sp = regs->sp; | |
169 | int onsigstack = on_sig_stack(sp); | |
170 | ||
171 | /* redzone */ | |
172 | sp -= STACK_FRAME_OVERHEAD; | |
173 | ||
174 | /* This is the X/Open sanctioned signal stack switching. */ | |
175 | if ((ka->sa.sa_flags & SA_ONSTACK) && !onsigstack) { | |
176 | if (current->sas_ss_size) | |
177 | sp = current->sas_ss_sp + current->sas_ss_size; | |
178 | } | |
179 | ||
180 | sp = align_sigframe(sp - frame_size); | |
181 | ||
182 | /* | |
183 | * If we are on the alternate signal stack and would overflow it, don't. | |
184 | * Return an always-bogus address instead so we will die with SIGSEGV. | |
185 | */ | |
186 | if (onsigstack && !likely(on_sig_stack(sp))) | |
187 | return (void __user *)-1L; | |
188 | ||
189 | return (void __user *)sp; | |
190 | } | |
191 | ||
192 | /* grab and setup a signal frame. | |
193 | * | |
194 | * basically we stack a lot of state info, and arrange for the | |
195 | * user-mode program to return to the kernel using either a | |
196 | * trampoline which performs the syscall sigreturn, or a provided | |
197 | * user-mode trampoline. | |
198 | */ | |
199 | static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
200 | sigset_t *set, struct pt_regs *regs) | |
201 | { | |
202 | struct rt_sigframe *frame; | |
203 | unsigned long return_ip; | |
204 | int err = 0; | |
205 | ||
206 | frame = get_sigframe(ka, regs, sizeof(*frame)); | |
207 | ||
208 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
209 | goto give_sigsegv; | |
210 | ||
211 | err |= __put_user(&frame->info, &frame->pinfo); | |
212 | err |= __put_user(&frame->uc, &frame->puc); | |
213 | ||
214 | if (ka->sa.sa_flags & SA_SIGINFO) | |
215 | err |= copy_siginfo_to_user(&frame->info, info); | |
216 | if (err) | |
217 | goto give_sigsegv; | |
218 | ||
219 | /* Clear all the bits of the ucontext we don't use. */ | |
220 | err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext)); | |
221 | err |= __put_user(0, &frame->uc.uc_flags); | |
222 | err |= __put_user(NULL, &frame->uc.uc_link); | |
223 | err |= __put_user((void *)current->sas_ss_sp, | |
224 | &frame->uc.uc_stack.ss_sp); | |
225 | err |= __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags); | |
226 | err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
227 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]); | |
228 | ||
229 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
230 | ||
231 | if (err) | |
232 | goto give_sigsegv; | |
233 | ||
234 | /* trampoline - the desired return ip is the retcode itself */ | |
235 | return_ip = (unsigned long)&frame->retcode; | |
236 | /* This is l.ori r11,r0,__NR_sigreturn, l.sys 1 */ | |
237 | err |= __put_user(0xa960, (short *)(frame->retcode + 0)); | |
238 | err |= __put_user(__NR_rt_sigreturn, (short *)(frame->retcode + 2)); | |
239 | err |= __put_user(0x20000001, (unsigned long *)(frame->retcode + 4)); | |
240 | err |= __put_user(0x15000000, (unsigned long *)(frame->retcode + 8)); | |
241 | ||
242 | if (err) | |
243 | goto give_sigsegv; | |
244 | ||
245 | /* TODO what is the current->exec_domain stuff and invmap ? */ | |
246 | ||
247 | /* Set up registers for signal handler */ | |
248 | regs->pc = (unsigned long)ka->sa.sa_handler; /* what we enter NOW */ | |
249 | regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */ | |
250 | regs->gpr[3] = (unsigned long)sig; /* arg 1: signo */ | |
251 | regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */ | |
252 | regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */ | |
253 | ||
254 | /* actually move the usp to reflect the stacked frame */ | |
255 | regs->sp = (unsigned long)frame; | |
256 | ||
257 | return; | |
258 | ||
259 | give_sigsegv: | |
260 | if (sig == SIGSEGV) | |
261 | ka->sa.sa_handler = SIG_DFL; | |
262 | force_sig(SIGSEGV, current); | |
263 | } | |
264 | ||
265 | static inline void | |
266 | handle_signal(unsigned long sig, | |
267 | siginfo_t *info, struct k_sigaction *ka, | |
268 | sigset_t *oldset, struct pt_regs *regs) | |
269 | { | |
270 | setup_rt_frame(sig, ka, info, oldset, regs); | |
271 | ||
272 | if (ka->sa.sa_flags & SA_ONESHOT) | |
273 | ka->sa.sa_handler = SIG_DFL; | |
274 | ||
275 | spin_lock_irq(¤t->sighand->siglock); | |
276 | sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); | |
277 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
278 | sigaddset(¤t->blocked, sig); | |
279 | recalc_sigpending(); | |
280 | ||
281 | spin_unlock_irq(¤t->sighand->siglock); | |
282 | } | |
283 | ||
284 | /* | |
285 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
286 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
287 | * mistake. | |
288 | * | |
289 | * Also note that the regs structure given here as an argument, is the latest | |
290 | * pushed pt_regs. It may or may not be the same as the first pushed registers | |
291 | * when the initial usermode->kernelmode transition took place. Therefore | |
292 | * we can use user_mode(regs) to see if we came directly from kernel or user | |
293 | * mode below. | |
294 | */ | |
295 | ||
296 | void do_signal(struct pt_regs *regs) | |
297 | { | |
298 | siginfo_t info; | |
299 | int signr; | |
300 | struct k_sigaction ka; | |
301 | ||
302 | /* | |
303 | * We want the common case to go fast, which | |
304 | * is why we may in certain cases get here from | |
305 | * kernel mode. Just return without doing anything | |
306 | * if so. | |
307 | */ | |
308 | if (!user_mode(regs)) | |
309 | return; | |
310 | ||
311 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
312 | ||
313 | /* If we are coming out of a syscall then we need | |
314 | * to check if the syscall was interrupted and wants to be | |
315 | * restarted after handling the signal. If so, the original | |
316 | * syscall number is put back into r11 and the PC rewound to | |
317 | * point at the l.sys instruction that resulted in the | |
318 | * original syscall. Syscall results other than the four | |
319 | * below mean that the syscall executed to completion and no | |
320 | * restart is necessary. | |
321 | */ | |
322 | if (regs->syscallno) { | |
323 | int restart = 0; | |
324 | ||
325 | switch (regs->gpr[11]) { | |
326 | case -ERESTART_RESTARTBLOCK: | |
327 | case -ERESTARTNOHAND: | |
328 | /* Restart if there is no signal handler */ | |
329 | restart = (signr <= 0); | |
330 | break; | |
331 | case -ERESTARTSYS: | |
332 | /* Restart if there no signal handler or | |
333 | * SA_RESTART flag is set */ | |
334 | restart = (signr <= 0 || (ka.sa.sa_flags & SA_RESTART)); | |
335 | break; | |
336 | case -ERESTARTNOINTR: | |
337 | /* Always restart */ | |
338 | restart = 1; | |
339 | break; | |
340 | } | |
341 | ||
342 | if (restart) { | |
343 | if (regs->gpr[11] == -ERESTART_RESTARTBLOCK) | |
344 | regs->gpr[11] = __NR_restart_syscall; | |
345 | else | |
346 | regs->gpr[11] = regs->orig_gpr11; | |
347 | regs->pc -= 4; | |
348 | } else { | |
349 | regs->gpr[11] = -EINTR; | |
350 | } | |
351 | } | |
352 | ||
353 | if (signr <= 0) { | |
354 | /* no signal to deliver so we just put the saved sigmask | |
355 | * back */ | |
356 | if (test_thread_flag(TIF_RESTORE_SIGMASK)) { | |
357 | clear_thread_flag(TIF_RESTORE_SIGMASK); | |
358 | sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); | |
359 | } | |
360 | ||
361 | } else { /* signr > 0 */ | |
362 | sigset_t *oldset; | |
363 | ||
364 | if (current_thread_info()->flags & _TIF_RESTORE_SIGMASK) | |
365 | oldset = ¤t->saved_sigmask; | |
366 | else | |
367 | oldset = ¤t->blocked; | |
368 | ||
369 | /* Whee! Actually deliver the signal. */ | |
370 | handle_signal(signr, &info, &ka, oldset, regs); | |
371 | /* a signal was successfully delivered; the saved | |
372 | * sigmask will have been stored in the signal frame, | |
373 | * and will be restored by sigreturn, so we can simply | |
374 | * clear the TIF_RESTORE_SIGMASK flag */ | |
375 | if (test_thread_flag(TIF_RESTORE_SIGMASK)) | |
376 | clear_thread_flag(TIF_RESTORE_SIGMASK); | |
377 | ||
378 | tracehook_signal_handler(signr, &info, &ka, regs, | |
379 | test_thread_flag(TIF_SINGLESTEP)); | |
380 | } | |
381 | ||
382 | return; | |
383 | } | |
384 | ||
385 | asmlinkage void do_notify_resume(struct pt_regs *regs) | |
386 | { | |
387 | if (current_thread_info()->flags & _TIF_SIGPENDING) | |
388 | do_signal(regs); | |
389 | ||
390 | if (current_thread_info()->flags & _TIF_NOTIFY_RESUME) { | |
391 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
392 | tracehook_notify_resume(regs); | |
393 | if (current->replacement_session_keyring) | |
394 | key_replace_session_keyring(); | |
395 | } | |
396 | } |