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cd5b61d6 RK |
1 | /* |
2 | * Signal support for Hexagon processor | |
3 | * | |
4 | * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 and | |
8 | * only version 2 as published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
18 | * 02110-1301, USA. | |
19 | */ | |
20 | ||
21 | #include <linux/linkage.h> | |
22 | #include <linux/syscalls.h> | |
23 | #include <linux/freezer.h> | |
24 | #include <linux/tracehook.h> | |
25 | #include <asm/registers.h> | |
26 | #include <asm/thread_info.h> | |
27 | #include <asm/unistd.h> | |
28 | #include <asm/uaccess.h> | |
29 | #include <asm/ucontext.h> | |
30 | #include <asm/cacheflush.h> | |
31 | #include <asm/signal.h> | |
32 | #include <asm/vdso.h> | |
33 | ||
34 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
35 | ||
36 | struct rt_sigframe { | |
37 | unsigned long tramp[2]; | |
38 | struct siginfo info; | |
39 | struct ucontext uc; | |
40 | }; | |
41 | ||
42 | static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, | |
43 | size_t frame_size) | |
44 | { | |
45 | unsigned long sp = regs->r29; | |
46 | ||
47 | /* Switch to signal stack if appropriate */ | |
48 | if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0)) | |
49 | sp = current->sas_ss_sp + current->sas_ss_size; | |
50 | ||
51 | return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); | |
52 | } | |
53 | ||
54 | static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) | |
55 | { | |
56 | unsigned long tmp; | |
57 | int err = 0; | |
58 | ||
59 | err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, | |
60 | 32*sizeof(unsigned long)); | |
61 | ||
62 | err |= __put_user(regs->sa0, &sc->sc_regs.sa0); | |
63 | err |= __put_user(regs->lc0, &sc->sc_regs.lc0); | |
64 | err |= __put_user(regs->sa1, &sc->sc_regs.sa1); | |
65 | err |= __put_user(regs->lc1, &sc->sc_regs.lc1); | |
66 | err |= __put_user(regs->m0, &sc->sc_regs.m0); | |
67 | err |= __put_user(regs->m1, &sc->sc_regs.m1); | |
68 | err |= __put_user(regs->usr, &sc->sc_regs.usr); | |
69 | err |= __put_user(regs->preds, &sc->sc_regs.p3_0); | |
70 | err |= __put_user(regs->gp, &sc->sc_regs.gp); | |
71 | err |= __put_user(regs->ugp, &sc->sc_regs.ugp); | |
72 | ||
73 | tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); | |
74 | tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); | |
75 | tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); | |
76 | ||
77 | return err; | |
78 | } | |
79 | ||
80 | static int restore_sigcontext(struct pt_regs *regs, | |
81 | struct sigcontext __user *sc) | |
82 | { | |
83 | unsigned long tmp; | |
84 | int err = 0; | |
85 | ||
86 | err |= copy_from_user(®s->r00, &sc->sc_regs.r0, | |
87 | 32 * sizeof(unsigned long)); | |
88 | ||
89 | err |= __get_user(regs->sa0, &sc->sc_regs.sa0); | |
90 | err |= __get_user(regs->lc0, &sc->sc_regs.lc0); | |
91 | err |= __get_user(regs->sa1, &sc->sc_regs.sa1); | |
92 | err |= __get_user(regs->lc1, &sc->sc_regs.lc1); | |
93 | err |= __get_user(regs->m0, &sc->sc_regs.m0); | |
94 | err |= __get_user(regs->m1, &sc->sc_regs.m1); | |
95 | err |= __get_user(regs->usr, &sc->sc_regs.usr); | |
96 | err |= __get_user(regs->preds, &sc->sc_regs.p3_0); | |
97 | err |= __get_user(regs->gp, &sc->sc_regs.gp); | |
98 | err |= __get_user(regs->ugp, &sc->sc_regs.ugp); | |
99 | ||
100 | err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); | |
101 | ||
102 | return err; | |
103 | } | |
104 | ||
105 | /* | |
106 | * Setup signal stack frame with siginfo structure | |
107 | */ | |
108 | static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info, | |
109 | sigset_t *set, struct pt_regs *regs) | |
110 | { | |
111 | int err = 0; | |
112 | struct rt_sigframe __user *frame; | |
113 | struct hexagon_vdso *vdso = current->mm->context.vdso; | |
114 | ||
115 | frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe)); | |
116 | ||
117 | if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe))) | |
118 | goto sigsegv; | |
119 | ||
120 | if (copy_siginfo_to_user(&frame->info, info)) | |
121 | goto sigsegv; | |
122 | ||
123 | /* The on-stack signal trampoline is no longer executed; | |
124 | * however, the libgcc signal frame unwinding code checks for | |
125 | * the presence of these two numeric magic values. | |
126 | */ | |
127 | err |= __put_user(0x7800d166, &frame->tramp[0]); | |
128 | err |= __put_user(0x5400c004, &frame->tramp[1]); | |
129 | err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); | |
130 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
131 | if (err) | |
132 | goto sigsegv; | |
133 | ||
134 | /* Load r0/r1 pair with signumber/siginfo pointer... */ | |
135 | regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) | |
136 | | (unsigned long long)signr; | |
137 | regs->r02 = (unsigned long) &frame->uc; | |
138 | regs->r31 = (unsigned long) vdso->rt_signal_trampoline; | |
139 | pt_psp(regs) = (unsigned long) frame; | |
140 | pt_set_elr(regs, (unsigned long)ka->sa.sa_handler); | |
141 | ||
142 | return 0; | |
143 | ||
144 | sigsegv: | |
145 | force_sigsegv(signr, current); | |
146 | return -EFAULT; | |
147 | } | |
148 | ||
149 | /* | |
150 | * Setup invocation of signal handler | |
151 | */ | |
152 | static int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, | |
153 | sigset_t *oldset, struct pt_regs *regs) | |
154 | { | |
155 | int rc; | |
156 | ||
157 | /* | |
158 | * If we're handling a signal that aborted a system call, | |
159 | * set up the error return value before adding the signal | |
160 | * frame to the stack. | |
161 | */ | |
162 | ||
163 | if (regs->syscall_nr >= 0) { | |
164 | switch (regs->r00) { | |
165 | case -ERESTART_RESTARTBLOCK: | |
166 | case -ERESTARTNOHAND: | |
167 | regs->r00 = -EINTR; | |
168 | break; | |
169 | case -ERESTARTSYS: | |
170 | if (!(ka->sa.sa_flags & SA_RESTART)) { | |
171 | regs->r00 = -EINTR; | |
172 | break; | |
173 | } | |
174 | /* Fall through */ | |
175 | case -ERESTARTNOINTR: | |
176 | regs->r06 = regs->syscall_nr; | |
177 | pt_set_elr(regs, pt_elr(regs) - 4); | |
178 | regs->r00 = regs->restart_r0; | |
179 | break; | |
180 | default: | |
181 | break; | |
182 | } | |
183 | } | |
184 | ||
185 | /* | |
186 | * Set up the stack frame; not doing the SA_SIGINFO thing. We | |
187 | * only set up the rt_frame flavor. | |
188 | */ | |
189 | rc = setup_rt_frame(sig, ka, info, oldset, regs); | |
190 | ||
191 | /* If there was an error on setup, no signal was delivered. */ | |
192 | if (rc) | |
193 | return rc; | |
194 | ||
43aca324 | 195 | block_sigmask(ka, sig); |
cd5b61d6 RK |
196 | |
197 | return 0; | |
198 | } | |
199 | ||
200 | /* | |
201 | * Called from return-from-event code. | |
202 | */ | |
203 | static void do_signal(struct pt_regs *regs) | |
204 | { | |
205 | struct k_sigaction sigact; | |
206 | siginfo_t info; | |
207 | int signo; | |
208 | ||
209 | if (!user_mode(regs)) | |
210 | return; | |
211 | ||
212 | if (try_to_freeze()) | |
213 | goto no_signal; | |
214 | ||
215 | signo = get_signal_to_deliver(&info, &sigact, regs, NULL); | |
216 | ||
217 | if (signo > 0) { | |
218 | sigset_t *oldset; | |
219 | ||
220 | if (test_thread_flag(TIF_RESTORE_SIGMASK)) | |
221 | oldset = ¤t->saved_sigmask; | |
222 | else | |
223 | oldset = ¤t->blocked; | |
224 | ||
225 | if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) { | |
226 | /* | |
227 | * Successful delivery case. The saved sigmask is | |
228 | * stored in the signal frame, and will be restored | |
229 | * by sigreturn. We can clear the TIF flag. | |
230 | */ | |
231 | clear_thread_flag(TIF_RESTORE_SIGMASK); | |
232 | ||
233 | tracehook_signal_handler(signo, &info, &sigact, regs, | |
234 | test_thread_flag(TIF_SINGLESTEP)); | |
235 | } | |
236 | return; | |
237 | } | |
238 | ||
239 | no_signal: | |
240 | /* | |
241 | * If we came from a system call, handle the restart. | |
242 | */ | |
243 | if (regs->syscall_nr >= 0) { | |
244 | switch (regs->r00) { | |
245 | case -ERESTARTNOHAND: | |
246 | case -ERESTARTSYS: | |
247 | case -ERESTARTNOINTR: | |
248 | regs->r06 = regs->syscall_nr; | |
249 | break; | |
250 | case -ERESTART_RESTARTBLOCK: | |
251 | regs->r06 = __NR_restart_syscall; | |
252 | break; | |
253 | default: | |
254 | goto no_restart; | |
255 | } | |
256 | pt_set_elr(regs, pt_elr(regs) - 4); | |
257 | regs->r00 = regs->restart_r0; | |
258 | } | |
259 | ||
260 | no_restart: | |
261 | /* If there's no signal to deliver, put the saved sigmask back */ | |
51a7b448 | 262 | restore_saved_sigmask(); |
cd5b61d6 RK |
263 | } |
264 | ||
265 | void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) | |
266 | { | |
267 | if (thread_info_flags & _TIF_SIGPENDING) | |
268 | do_signal(regs); | |
269 | ||
270 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { | |
271 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
3334bf12 | 272 | tracehook_notify_resume(regs); |
cd5b61d6 RK |
273 | } |
274 | } | |
275 | ||
276 | /* | |
277 | * Architecture-specific wrappers for signal-related system calls | |
278 | */ | |
279 | asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss) | |
280 | { | |
281 | struct pt_regs *regs = current_thread_info()->regs; | |
282 | ||
283 | return do_sigaltstack(uss, uoss, regs->r29); | |
284 | } | |
285 | ||
286 | asmlinkage int sys_rt_sigreturn(void) | |
287 | { | |
288 | struct pt_regs *regs = current_thread_info()->regs; | |
289 | struct rt_sigframe __user *frame; | |
290 | sigset_t blocked; | |
291 | ||
ef9b122f AV |
292 | /* Always make any pending restarted system calls return -EINTR */ |
293 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
294 | ||
cd5b61d6 RK |
295 | frame = (struct rt_sigframe __user *)pt_psp(regs); |
296 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
297 | goto badframe; | |
298 | if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) | |
299 | goto badframe; | |
300 | ||
301 | sigdelsetmask(&blocked, ~_BLOCKABLE); | |
43aca324 | 302 | set_current_blocked(&blocked); |
cd5b61d6 RK |
303 | |
304 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
305 | goto badframe; | |
306 | ||
307 | /* Restore the user's stack as well */ | |
308 | pt_psp(regs) = regs->r29; | |
309 | ||
310 | /* | |
311 | * Leave a trace in the stack frame that this was a sigreturn. | |
312 | * If the system call is to replay, we've already restored the | |
313 | * number in the GPR slot and it will be regenerated on the | |
314 | * new system call trap entry. Note that if restore_sigcontext() | |
315 | * did something other than a bulk copy of the pt_regs struct, | |
316 | * we could avoid this assignment by simply not overwriting | |
317 | * regs->syscall_nr. | |
318 | */ | |
319 | regs->syscall_nr = __NR_rt_sigreturn; | |
320 | ||
321 | /* | |
322 | * If we were meticulous, we'd only call this if we knew that | |
323 | * we were actually going to use an alternate stack, and we'd | |
324 | * consider any error to be fatal. What we do here, in common | |
325 | * with many other architectures, is call it blindly and only | |
326 | * consider the -EFAULT return case to be proof of a problem. | |
327 | */ | |
328 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT) | |
329 | goto badframe; | |
330 | ||
331 | return 0; | |
332 | ||
333 | badframe: | |
334 | force_sig(SIGSEGV, current); | |
335 | return 0; | |
336 | } |