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1/*
2 * Signal support for Hexagon processor
3 *
4 * Copyright (c) 2010-2012, The Linux Foundation. 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/tracehook.h>
24#include <linux/sched/task_stack.h>
25
26#include <asm/registers.h>
27#include <asm/thread_info.h>
28#include <asm/unistd.h>
29#include <linux/uaccess.h>
30#include <asm/ucontext.h>
31#include <asm/cacheflush.h>
32#include <asm/signal.h>
33#include <asm/vdso.h>
34
35struct rt_sigframe {
36 unsigned long tramp[2];
37 struct siginfo info;
38 struct ucontext uc;
39};
40
41static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
42 size_t frame_size)
43{
44 unsigned long sp = sigsp(regs->r29, ksig);
45
46 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
47}
48
49static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
50{
51 unsigned long tmp;
52 int err = 0;
53
54 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00,
55 32*sizeof(unsigned long));
56
57 err |= __put_user(regs->sa0, &sc->sc_regs.sa0);
58 err |= __put_user(regs->lc0, &sc->sc_regs.lc0);
59 err |= __put_user(regs->sa1, &sc->sc_regs.sa1);
60 err |= __put_user(regs->lc1, &sc->sc_regs.lc1);
61 err |= __put_user(regs->m0, &sc->sc_regs.m0);
62 err |= __put_user(regs->m1, &sc->sc_regs.m1);
63 err |= __put_user(regs->usr, &sc->sc_regs.usr);
64 err |= __put_user(regs->preds, &sc->sc_regs.p3_0);
65 err |= __put_user(regs->gp, &sc->sc_regs.gp);
66 err |= __put_user(regs->ugp, &sc->sc_regs.ugp);
67#if CONFIG_HEXAGON_ARCH_VERSION >= 4
68 err |= __put_user(regs->cs0, &sc->sc_regs.cs0);
69 err |= __put_user(regs->cs1, &sc->sc_regs.cs1);
70#endif
71 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc);
72 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause);
73 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva);
74
75 return err;
76}
77
78static int restore_sigcontext(struct pt_regs *regs,
79 struct sigcontext __user *sc)
80{
81 unsigned long tmp;
82 int err = 0;
83
84 err |= copy_from_user(®s->r00, &sc->sc_regs.r0,
85 32 * sizeof(unsigned long));
86
87 err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
88 err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
89 err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
90 err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
91 err |= __get_user(regs->m0, &sc->sc_regs.m0);
92 err |= __get_user(regs->m1, &sc->sc_regs.m1);
93 err |= __get_user(regs->usr, &sc->sc_regs.usr);
94 err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
95 err |= __get_user(regs->gp, &sc->sc_regs.gp);
96 err |= __get_user(regs->ugp, &sc->sc_regs.ugp);
97#if CONFIG_HEXAGON_ARCH_VERSION >= 4
98 err |= __get_user(regs->cs0, &sc->sc_regs.cs0);
99 err |= __get_user(regs->cs1, &sc->sc_regs.cs1);
100#endif
101 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
102
103 return err;
104}
105
106/*
107 * Setup signal stack frame with siginfo structure
108 */
109static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
110 struct pt_regs *regs)
111{
112 int err = 0;
113 struct rt_sigframe __user *frame;
114 struct hexagon_vdso *vdso = current->mm->context.vdso;
115
116 frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe));
117
118 if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
119 return -EFAULT;
120
121 if (copy_siginfo_to_user(&frame->info, &ksig->info))
122 return -EFAULT;
123
124 /* The on-stack signal trampoline is no longer executed;
125 * however, the libgcc signal frame unwinding code checks for
126 * the presence of these two numeric magic values.
127 */
128 err |= __put_user(0x7800d166, &frame->tramp[0]);
129 err |= __put_user(0x5400c004, &frame->tramp[1]);
130 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
131 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
132 err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs));
133 if (err)
134 return -EFAULT;
135
136 /* Load r0/r1 pair with signumber/siginfo pointer... */
137 regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
138 | (unsigned long long)ksig->sig;
139 regs->r02 = (unsigned long) &frame->uc;
140 regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
141 pt_psp(regs) = (unsigned long) frame;
142 pt_set_elr(regs, (unsigned long)ksig->ka.sa.sa_handler);
143
144 return 0;
145}
146
147/*
148 * Setup invocation of signal handler
149 */
150static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
151{
152 int ret;
153
154 /*
155 * If we're handling a signal that aborted a system call,
156 * set up the error return value before adding the signal
157 * frame to the stack.
158 */
159
160 if (regs->syscall_nr >= 0) {
161 switch (regs->r00) {
162 case -ERESTART_RESTARTBLOCK:
163 case -ERESTARTNOHAND:
164 regs->r00 = -EINTR;
165 break;
166 case -ERESTARTSYS:
167 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
168 regs->r00 = -EINTR;
169 break;
170 }
171 /* Fall through */
172 case -ERESTARTNOINTR:
173 regs->r06 = regs->syscall_nr;
174 pt_set_elr(regs, pt_elr(regs) - 4);
175 regs->r00 = regs->restart_r0;
176 break;
177 default:
178 break;
179 }
180 }
181
182 /*
183 * Set up the stack frame; not doing the SA_SIGINFO thing. We
184 * only set up the rt_frame flavor.
185 */
186 /* If there was an error on setup, no signal was delivered. */
187 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
188
189 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
190}
191
192/*
193 * Called from return-from-event code.
194 */
195void do_signal(struct pt_regs *regs)
196{
197 struct ksignal ksig;
198
199 if (!user_mode(regs))
200 return;
201
202 if (get_signal(&ksig)) {
203 handle_signal(&ksig, regs);
204 return;
205 }
206
207 /*
208 * No (more) signals; if we came from a system call, handle the restart.
209 */
210
211 if (regs->syscall_nr >= 0) {
212 switch (regs->r00) {
213 case -ERESTARTNOHAND:
214 case -ERESTARTSYS:
215 case -ERESTARTNOINTR:
216 regs->r06 = regs->syscall_nr;
217 break;
218 case -ERESTART_RESTARTBLOCK:
219 regs->r06 = __NR_restart_syscall;
220 break;
221 default:
222 goto no_restart;
223 }
224 pt_set_elr(regs, pt_elr(regs) - 4);
225 regs->r00 = regs->restart_r0;
226 }
227
228no_restart:
229 /* If there's no signal to deliver, put the saved sigmask back */
230 restore_saved_sigmask();
231}
232
233/*
234 * Architecture-specific wrappers for signal-related system calls
235 */
236
237asmlinkage int sys_rt_sigreturn(void)
238{
239 struct pt_regs *regs = current_pt_regs();
240 struct rt_sigframe __user *frame;
241 sigset_t blocked;
242
243 /* Always make any pending restarted system calls return -EINTR */
244 current->restart_block.fn = do_no_restart_syscall;
245
246 frame = (struct rt_sigframe __user *)pt_psp(regs);
247 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
248 goto badframe;
249 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
250 goto badframe;
251
252 set_current_blocked(&blocked);
253
254 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
255 goto badframe;
256
257 /* Restore the user's stack as well */
258 pt_psp(regs) = regs->r29;
259
260 regs->syscall_nr = -1;
261
262 if (restore_altstack(&frame->uc.uc_stack))
263 goto badframe;
264
265 return regs->r00;
266
267badframe:
268 force_sig(SIGSEGV, current);
269 return 0;
270}
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
34struct rt_sigframe {
35 unsigned long tramp[2];
36 struct siginfo info;
37 struct ucontext uc;
38};
39
40static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
41 size_t frame_size)
42{
43 unsigned long sp = regs->r29;
44
45 /* Switch to signal stack if appropriate */
46 if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
47 sp = current->sas_ss_sp + current->sas_ss_size;
48
49 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
50}
51
52static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
53{
54 unsigned long tmp;
55 int err = 0;
56
57 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00,
58 32*sizeof(unsigned long));
59
60 err |= __put_user(regs->sa0, &sc->sc_regs.sa0);
61 err |= __put_user(regs->lc0, &sc->sc_regs.lc0);
62 err |= __put_user(regs->sa1, &sc->sc_regs.sa1);
63 err |= __put_user(regs->lc1, &sc->sc_regs.lc1);
64 err |= __put_user(regs->m0, &sc->sc_regs.m0);
65 err |= __put_user(regs->m1, &sc->sc_regs.m1);
66 err |= __put_user(regs->usr, &sc->sc_regs.usr);
67 err |= __put_user(regs->preds, &sc->sc_regs.p3_0);
68 err |= __put_user(regs->gp, &sc->sc_regs.gp);
69 err |= __put_user(regs->ugp, &sc->sc_regs.ugp);
70
71 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc);
72 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause);
73 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva);
74
75 return err;
76}
77
78static int restore_sigcontext(struct pt_regs *regs,
79 struct sigcontext __user *sc)
80{
81 unsigned long tmp;
82 int err = 0;
83
84 err |= copy_from_user(®s->r00, &sc->sc_regs.r0,
85 32 * sizeof(unsigned long));
86
87 err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
88 err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
89 err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
90 err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
91 err |= __get_user(regs->m0, &sc->sc_regs.m0);
92 err |= __get_user(regs->m1, &sc->sc_regs.m1);
93 err |= __get_user(regs->usr, &sc->sc_regs.usr);
94 err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
95 err |= __get_user(regs->gp, &sc->sc_regs.gp);
96 err |= __get_user(regs->ugp, &sc->sc_regs.ugp);
97
98 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
99
100 return err;
101}
102
103/*
104 * Setup signal stack frame with siginfo structure
105 */
106static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
107 sigset_t *set, struct pt_regs *regs)
108{
109 int err = 0;
110 struct rt_sigframe __user *frame;
111 struct hexagon_vdso *vdso = current->mm->context.vdso;
112
113 frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
114
115 if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
116 goto sigsegv;
117
118 if (copy_siginfo_to_user(&frame->info, info))
119 goto sigsegv;
120
121 /* The on-stack signal trampoline is no longer executed;
122 * however, the libgcc signal frame unwinding code checks for
123 * the presence of these two numeric magic values.
124 */
125 err |= __put_user(0x7800d166, &frame->tramp[0]);
126 err |= __put_user(0x5400c004, &frame->tramp[1]);
127 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
128 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
129 if (err)
130 goto sigsegv;
131
132 /* Load r0/r1 pair with signumber/siginfo pointer... */
133 regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
134 | (unsigned long long)signr;
135 regs->r02 = (unsigned long) &frame->uc;
136 regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
137 pt_psp(regs) = (unsigned long) frame;
138 pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);
139
140 return 0;
141
142sigsegv:
143 force_sigsegv(signr, current);
144 return -EFAULT;
145}
146
147/*
148 * Setup invocation of signal handler
149 */
150static void handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
151 struct pt_regs *regs)
152{
153 /*
154 * If we're handling a signal that aborted a system call,
155 * set up the error return value before adding the signal
156 * frame to the stack.
157 */
158
159 if (regs->syscall_nr >= 0) {
160 switch (regs->r00) {
161 case -ERESTART_RESTARTBLOCK:
162 case -ERESTARTNOHAND:
163 regs->r00 = -EINTR;
164 break;
165 case -ERESTARTSYS:
166 if (!(ka->sa.sa_flags & SA_RESTART)) {
167 regs->r00 = -EINTR;
168 break;
169 }
170 /* Fall through */
171 case -ERESTARTNOINTR:
172 regs->r06 = regs->syscall_nr;
173 pt_set_elr(regs, pt_elr(regs) - 4);
174 regs->r00 = regs->restart_r0;
175 break;
176 default:
177 break;
178 }
179 }
180
181 /*
182 * Set up the stack frame; not doing the SA_SIGINFO thing. We
183 * only set up the rt_frame flavor.
184 */
185 /* If there was an error on setup, no signal was delivered. */
186 if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
187 return;
188
189 signal_delivered(sig, info, ka, regs,
190 test_thread_flag(TIF_SINGLESTEP));
191}
192
193/*
194 * Called from return-from-event code.
195 */
196static void do_signal(struct pt_regs *regs)
197{
198 struct k_sigaction sigact;
199 siginfo_t info;
200 int signo;
201
202 if (!user_mode(regs))
203 return;
204
205 signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
206
207 if (signo > 0) {
208 handle_signal(signo, &info, &sigact, regs);
209 return;
210 }
211
212 /*
213 * If we came from a system call, handle the restart.
214 */
215 if (regs->syscall_nr >= 0) {
216 switch (regs->r00) {
217 case -ERESTARTNOHAND:
218 case -ERESTARTSYS:
219 case -ERESTARTNOINTR:
220 regs->r06 = regs->syscall_nr;
221 break;
222 case -ERESTART_RESTARTBLOCK:
223 regs->r06 = __NR_restart_syscall;
224 break;
225 default:
226 goto no_restart;
227 }
228 pt_set_elr(regs, pt_elr(regs) - 4);
229 regs->r00 = regs->restart_r0;
230 }
231
232no_restart:
233 /* If there's no signal to deliver, put the saved sigmask back */
234 restore_saved_sigmask();
235}
236
237void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
238{
239 if (thread_info_flags & _TIF_SIGPENDING)
240 do_signal(regs);
241
242 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
243 clear_thread_flag(TIF_NOTIFY_RESUME);
244 tracehook_notify_resume(regs);
245 }
246}
247
248/*
249 * Architecture-specific wrappers for signal-related system calls
250 */
251asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
252{
253 struct pt_regs *regs = current_thread_info()->regs;
254
255 return do_sigaltstack(uss, uoss, regs->r29);
256}
257
258asmlinkage int sys_rt_sigreturn(void)
259{
260 struct pt_regs *regs = current_thread_info()->regs;
261 struct rt_sigframe __user *frame;
262 sigset_t blocked;
263
264 /* Always make any pending restarted system calls return -EINTR */
265 current_thread_info()->restart_block.fn = do_no_restart_syscall;
266
267 frame = (struct rt_sigframe __user *)pt_psp(regs);
268 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
269 goto badframe;
270 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
271 goto badframe;
272
273 set_current_blocked(&blocked);
274
275 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
276 goto badframe;
277
278 /* Restore the user's stack as well */
279 pt_psp(regs) = regs->r29;
280
281 /*
282 * Leave a trace in the stack frame that this was a sigreturn.
283 * If the system call is to replay, we've already restored the
284 * number in the GPR slot and it will be regenerated on the
285 * new system call trap entry. Note that if restore_sigcontext()
286 * did something other than a bulk copy of the pt_regs struct,
287 * we could avoid this assignment by simply not overwriting
288 * regs->syscall_nr.
289 */
290 regs->syscall_nr = __NR_rt_sigreturn;
291
292 /*
293 * If we were meticulous, we'd only call this if we knew that
294 * we were actually going to use an alternate stack, and we'd
295 * consider any error to be fatal. What we do here, in common
296 * with many other architectures, is call it blindly and only
297 * consider the -EFAULT return case to be proof of a problem.
298 */
299 if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT)
300 goto badframe;
301
302 return 0;
303
304badframe:
305 force_sig(SIGSEGV, current);
306 return 0;
307}