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867e359b CM |
1 | /* |
2 | * Copyright (C) 1991, 1992 Linus Torvalds | |
3 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation, version 2. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, but | |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
12 | * NON INFRINGEMENT. See the GNU General Public License for | |
13 | * more details. | |
14 | */ | |
15 | ||
16 | #include <linux/sched.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/smp.h> | |
19 | #include <linux/smp_lock.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/signal.h> | |
22 | #include <linux/errno.h> | |
23 | #include <linux/wait.h> | |
24 | #include <linux/unistd.h> | |
25 | #include <linux/stddef.h> | |
26 | #include <linux/personality.h> | |
27 | #include <linux/suspend.h> | |
28 | #include <linux/ptrace.h> | |
29 | #include <linux/elf.h> | |
30 | #include <linux/compat.h> | |
31 | #include <linux/syscalls.h> | |
32 | #include <linux/uaccess.h> | |
33 | #include <asm/processor.h> | |
34 | #include <asm/ucontext.h> | |
35 | #include <asm/sigframe.h> | |
0707ad30 | 36 | #include <asm/syscalls.h> |
867e359b CM |
37 | #include <arch/interrupts.h> |
38 | ||
39 | #define DEBUG_SIG 0 | |
40 | ||
41 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
42 | ||
43 | ||
139ef32b | 44 | long _sys_sigaltstack(const stack_t __user *uss, |
0707ad30 | 45 | stack_t __user *uoss, struct pt_regs *regs) |
867e359b CM |
46 | { |
47 | return do_sigaltstack(uss, uoss, regs->sp); | |
48 | } | |
49 | ||
50 | ||
51 | /* | |
52 | * Do a signal return; undo the signal stack. | |
53 | */ | |
54 | ||
55 | int restore_sigcontext(struct pt_regs *regs, | |
56 | struct sigcontext __user *sc, long *pr0) | |
57 | { | |
58 | int err = 0; | |
59 | int i; | |
60 | ||
61 | /* Always make any pending restarted system calls return -EINTR */ | |
62 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
63 | ||
64 | for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) | |
65 | err |= __get_user(((long *)regs)[i], | |
0707ad30 | 66 | &((long __user *)(&sc->regs))[i]); |
867e359b CM |
67 | |
68 | regs->faultnum = INT_SWINT_1_SIGRETURN; | |
69 | ||
70 | err |= __get_user(*pr0, &sc->regs.regs[0]); | |
71 | return err; | |
72 | } | |
73 | ||
0707ad30 CM |
74 | /* sigreturn() returns long since it restores r0 in the interrupted code. */ |
75 | long _sys_rt_sigreturn(struct pt_regs *regs) | |
867e359b CM |
76 | { |
77 | struct rt_sigframe __user *frame = | |
78 | (struct rt_sigframe __user *)(regs->sp); | |
79 | sigset_t set; | |
80 | long r0; | |
81 | ||
82 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
83 | goto badframe; | |
84 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
85 | goto badframe; | |
86 | ||
87 | sigdelsetmask(&set, ~_BLOCKABLE); | |
88 | spin_lock_irq(¤t->sighand->siglock); | |
89 | current->blocked = set; | |
90 | recalc_sigpending(); | |
91 | spin_unlock_irq(¤t->sighand->siglock); | |
92 | ||
93 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) | |
94 | goto badframe; | |
95 | ||
96 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT) | |
97 | goto badframe; | |
98 | ||
99 | return r0; | |
100 | ||
101 | badframe: | |
102 | force_sig(SIGSEGV, current); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * Set up a signal frame. | |
108 | */ | |
109 | ||
110 | int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) | |
111 | { | |
112 | int i, err = 0; | |
113 | ||
114 | for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) | |
115 | err |= __put_user(((long *)regs)[i], | |
0707ad30 | 116 | &((long __user *)(&sc->regs))[i]); |
867e359b CM |
117 | |
118 | return err; | |
119 | } | |
120 | ||
121 | /* | |
122 | * Determine which stack to use.. | |
123 | */ | |
124 | static inline void __user *get_sigframe(struct k_sigaction *ka, | |
125 | struct pt_regs *regs, | |
126 | size_t frame_size) | |
127 | { | |
128 | unsigned long sp; | |
129 | ||
130 | /* Default to using normal stack */ | |
131 | sp = regs->sp; | |
132 | ||
133 | /* | |
134 | * If we are on the alternate signal stack and would overflow | |
135 | * it, don't. Return an always-bogus address instead so we | |
136 | * will die with SIGSEGV. | |
137 | */ | |
138 | if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size))) | |
0707ad30 | 139 | return (void __user __force *)-1UL; |
867e359b CM |
140 | |
141 | /* This is the X/Open sanctioned signal stack switching. */ | |
142 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
143 | if (sas_ss_flags(sp) == 0) | |
144 | sp = current->sas_ss_sp + current->sas_ss_size; | |
145 | } | |
146 | ||
147 | sp -= frame_size; | |
148 | /* | |
149 | * Align the stack pointer according to the TILE ABI, | |
150 | * i.e. so that on function entry (sp & 15) == 0. | |
151 | */ | |
152 | sp &= -16UL; | |
153 | return (void __user *) sp; | |
154 | } | |
155 | ||
156 | static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
157 | sigset_t *set, struct pt_regs *regs) | |
158 | { | |
159 | unsigned long restorer; | |
160 | struct rt_sigframe __user *frame; | |
161 | int err = 0; | |
162 | int usig; | |
163 | ||
164 | frame = get_sigframe(ka, regs, sizeof(*frame)); | |
165 | ||
166 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
167 | goto give_sigsegv; | |
168 | ||
169 | usig = current_thread_info()->exec_domain | |
170 | && current_thread_info()->exec_domain->signal_invmap | |
171 | && sig < 32 | |
172 | ? current_thread_info()->exec_domain->signal_invmap[sig] | |
173 | : sig; | |
174 | ||
175 | /* Always write at least the signal number for the stack backtracer. */ | |
176 | if (ka->sa.sa_flags & SA_SIGINFO) { | |
177 | /* At sigreturn time, restore the callee-save registers too. */ | |
178 | err |= copy_siginfo_to_user(&frame->info, info); | |
179 | regs->flags |= PT_FLAGS_RESTORE_REGS; | |
180 | } else { | |
181 | err |= __put_user(info->si_signo, &frame->info.si_signo); | |
182 | } | |
183 | ||
184 | /* Create the ucontext. */ | |
185 | err |= __clear_user(&frame->save_area, sizeof(frame->save_area)); | |
186 | err |= __put_user(0, &frame->uc.uc_flags); | |
0707ad30 CM |
187 | err |= __put_user(NULL, &frame->uc.uc_link); |
188 | err |= __put_user((void __user *)(current->sas_ss_sp), | |
867e359b CM |
189 | &frame->uc.uc_stack.ss_sp); |
190 | err |= __put_user(sas_ss_flags(regs->sp), | |
191 | &frame->uc.uc_stack.ss_flags); | |
192 | err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
193 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); | |
194 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
195 | if (err) | |
196 | goto give_sigsegv; | |
197 | ||
198 | restorer = VDSO_BASE; | |
199 | if (ka->sa.sa_flags & SA_RESTORER) | |
200 | restorer = (unsigned long) ka->sa.sa_restorer; | |
201 | ||
202 | /* | |
203 | * Set up registers for signal handler. | |
204 | * Registers that we don't modify keep the value they had from | |
205 | * user-space at the time we took the signal. | |
206 | */ | |
207 | regs->pc = (unsigned long) ka->sa.sa_handler; | |
208 | regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */ | |
209 | regs->sp = (unsigned long) frame; | |
210 | regs->lr = restorer; | |
211 | regs->regs[0] = (unsigned long) usig; | |
212 | ||
213 | if (ka->sa.sa_flags & SA_SIGINFO) { | |
214 | /* Need extra arguments, so mark to restore caller-saves. */ | |
215 | regs->regs[1] = (unsigned long) &frame->info; | |
216 | regs->regs[2] = (unsigned long) &frame->uc; | |
217 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
218 | } | |
219 | ||
220 | /* | |
221 | * Notify any tracer that was single-stepping it. | |
222 | * The tracer may want to single-step inside the | |
223 | * handler too. | |
224 | */ | |
225 | if (test_thread_flag(TIF_SINGLESTEP)) | |
226 | ptrace_notify(SIGTRAP); | |
227 | ||
228 | return 0; | |
229 | ||
230 | give_sigsegv: | |
231 | force_sigsegv(sig, current); | |
232 | return -EFAULT; | |
233 | } | |
234 | ||
235 | /* | |
236 | * OK, we're invoking a handler | |
237 | */ | |
238 | ||
239 | static int handle_signal(unsigned long sig, siginfo_t *info, | |
240 | struct k_sigaction *ka, sigset_t *oldset, | |
241 | struct pt_regs *regs) | |
242 | { | |
243 | int ret; | |
244 | ||
245 | ||
246 | /* Are we from a system call? */ | |
247 | if (regs->faultnum == INT_SWINT_1) { | |
248 | /* If so, check system call restarting.. */ | |
249 | switch (regs->regs[0]) { | |
250 | case -ERESTART_RESTARTBLOCK: | |
251 | case -ERESTARTNOHAND: | |
252 | regs->regs[0] = -EINTR; | |
253 | break; | |
254 | ||
255 | case -ERESTARTSYS: | |
256 | if (!(ka->sa.sa_flags & SA_RESTART)) { | |
257 | regs->regs[0] = -EINTR; | |
258 | break; | |
259 | } | |
260 | /* fallthrough */ | |
261 | case -ERESTARTNOINTR: | |
262 | /* Reload caller-saves to restore r0..r5 and r10. */ | |
263 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
264 | regs->regs[0] = regs->orig_r0; | |
265 | regs->pc -= 8; | |
266 | } | |
267 | } | |
268 | ||
269 | /* Set up the stack frame */ | |
270 | #ifdef CONFIG_COMPAT | |
271 | if (is_compat_task()) | |
272 | ret = compat_setup_rt_frame(sig, ka, info, oldset, regs); | |
273 | else | |
274 | #endif | |
275 | ret = setup_rt_frame(sig, ka, info, oldset, regs); | |
276 | if (ret == 0) { | |
277 | /* This code is only called from system calls or from | |
278 | * the work_pending path in the return-to-user code, and | |
279 | * either way we can re-enable interrupts unconditionally. | |
280 | */ | |
281 | spin_lock_irq(¤t->sighand->siglock); | |
282 | sigorsets(¤t->blocked, | |
283 | ¤t->blocked, &ka->sa.sa_mask); | |
284 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
285 | sigaddset(¤t->blocked, sig); | |
286 | recalc_sigpending(); | |
287 | spin_unlock_irq(¤t->sighand->siglock); | |
288 | } | |
289 | ||
290 | return ret; | |
291 | } | |
292 | ||
293 | /* | |
294 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
295 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
296 | * mistake. | |
297 | */ | |
298 | void do_signal(struct pt_regs *regs) | |
299 | { | |
300 | siginfo_t info; | |
301 | int signr; | |
302 | struct k_sigaction ka; | |
303 | sigset_t *oldset; | |
304 | ||
305 | /* | |
306 | * i386 will check if we're coming from kernel mode and bail out | |
307 | * here. In my experience this just turns weird crashes into | |
308 | * weird spin-hangs. But if we find a case where this seems | |
309 | * helpful, we can reinstate the check on "!user_mode(regs)". | |
310 | */ | |
311 | ||
312 | if (current_thread_info()->status & TS_RESTORE_SIGMASK) | |
313 | oldset = ¤t->saved_sigmask; | |
314 | else | |
315 | oldset = ¤t->blocked; | |
316 | ||
317 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
318 | if (signr > 0) { | |
319 | /* Whee! Actually deliver the signal. */ | |
320 | if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { | |
321 | /* | |
322 | * A signal was successfully delivered; the saved | |
323 | * sigmask will have been stored in the signal frame, | |
324 | * and will be restored by sigreturn, so we can simply | |
325 | * clear the TS_RESTORE_SIGMASK flag. | |
326 | */ | |
327 | current_thread_info()->status &= ~TS_RESTORE_SIGMASK; | |
328 | } | |
329 | ||
330 | return; | |
331 | } | |
332 | ||
333 | /* Did we come from a system call? */ | |
334 | if (regs->faultnum == INT_SWINT_1) { | |
335 | /* Restart the system call - no handlers present */ | |
336 | switch (regs->regs[0]) { | |
337 | case -ERESTARTNOHAND: | |
338 | case -ERESTARTSYS: | |
339 | case -ERESTARTNOINTR: | |
340 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
341 | regs->regs[0] = regs->orig_r0; | |
342 | regs->pc -= 8; | |
343 | break; | |
344 | ||
345 | case -ERESTART_RESTARTBLOCK: | |
346 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
347 | regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall; | |
348 | regs->pc -= 8; | |
349 | break; | |
350 | } | |
351 | } | |
352 | ||
353 | /* If there's no signal to deliver, just put the saved sigmask back. */ | |
354 | if (current_thread_info()->status & TS_RESTORE_SIGMASK) { | |
355 | current_thread_info()->status &= ~TS_RESTORE_SIGMASK; | |
356 | sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); | |
357 | } | |
358 | } |