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 <asm/registers.h>
25 #include <asm/thread_info.h>
26 #include <asm/unistd.h>
27 #include <asm/uaccess.h>
28 #include <asm/ucontext.h>
29 #include <asm/cacheflush.h>
30 #include <asm/signal.h>
31 #include <asm/vdso.h>
32
33 struct rt_sigframe {
34 unsigned long tramp[2];
35 struct siginfo info;
36 struct ucontext uc;
37 };
38
get_sigframe(struct ksignal * ksig,struct pt_regs * regs,size_t frame_size)39 static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
40 size_t frame_size)
41 {
42 unsigned long sp = sigsp(regs->r29, ksig);
43
44 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
45 }
46
setup_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc)47 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
48 {
49 unsigned long tmp;
50 int err = 0;
51
52 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00,
53 32*sizeof(unsigned long));
54
55 err |= __put_user(regs->sa0, &sc->sc_regs.sa0);
56 err |= __put_user(regs->lc0, &sc->sc_regs.lc0);
57 err |= __put_user(regs->sa1, &sc->sc_regs.sa1);
58 err |= __put_user(regs->lc1, &sc->sc_regs.lc1);
59 err |= __put_user(regs->m0, &sc->sc_regs.m0);
60 err |= __put_user(regs->m1, &sc->sc_regs.m1);
61 err |= __put_user(regs->usr, &sc->sc_regs.usr);
62 err |= __put_user(regs->preds, &sc->sc_regs.p3_0);
63 err |= __put_user(regs->gp, &sc->sc_regs.gp);
64 err |= __put_user(regs->ugp, &sc->sc_regs.ugp);
65 #if CONFIG_HEXAGON_ARCH_VERSION >= 4
66 err |= __put_user(regs->cs0, &sc->sc_regs.cs0);
67 err |= __put_user(regs->cs1, &sc->sc_regs.cs1);
68 #endif
69 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc);
70 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause);
71 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva);
72
73 return err;
74 }
75
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc)76 static int restore_sigcontext(struct pt_regs *regs,
77 struct sigcontext __user *sc)
78 {
79 unsigned long tmp;
80 int err = 0;
81
82 err |= copy_from_user(®s->r00, &sc->sc_regs.r0,
83 32 * sizeof(unsigned long));
84
85 err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
86 err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
87 err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
88 err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
89 err |= __get_user(regs->m0, &sc->sc_regs.m0);
90 err |= __get_user(regs->m1, &sc->sc_regs.m1);
91 err |= __get_user(regs->usr, &sc->sc_regs.usr);
92 err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
93 err |= __get_user(regs->gp, &sc->sc_regs.gp);
94 err |= __get_user(regs->ugp, &sc->sc_regs.ugp);
95 #if CONFIG_HEXAGON_ARCH_VERSION >= 4
96 err |= __get_user(regs->cs0, &sc->sc_regs.cs0);
97 err |= __get_user(regs->cs1, &sc->sc_regs.cs1);
98 #endif
99 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
100
101 return err;
102 }
103
104 /*
105 * Setup signal stack frame with siginfo structure
106 */
setup_rt_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)107 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
108 struct pt_regs *regs)
109 {
110 int err = 0;
111 struct rt_sigframe __user *frame;
112 struct hexagon_vdso *vdso = current->mm->context.vdso;
113
114 frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe));
115
116 if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
117 return -EFAULT;
118
119 if (copy_siginfo_to_user(&frame->info, &ksig->info))
120 return -EFAULT;
121
122 /* The on-stack signal trampoline is no longer executed;
123 * however, the libgcc signal frame unwinding code checks for
124 * the presence of these two numeric magic values.
125 */
126 err |= __put_user(0x7800d166, &frame->tramp[0]);
127 err |= __put_user(0x5400c004, &frame->tramp[1]);
128 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
129 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
130 err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs));
131 if (err)
132 return -EFAULT;
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)ksig->sig;
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)ksig->ka.sa.sa_handler);
141
142 return 0;
143 }
144
145 /*
146 * Setup invocation of signal handler
147 */
handle_signal(struct ksignal * ksig,struct pt_regs * regs)148 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
149 {
150 int ret;
151
152 /*
153 * If we're handling a signal that aborted a system call,
154 * set up the error return value before adding the signal
155 * frame to the stack.
156 */
157
158 if (regs->syscall_nr >= 0) {
159 switch (regs->r00) {
160 case -ERESTART_RESTARTBLOCK:
161 case -ERESTARTNOHAND:
162 regs->r00 = -EINTR;
163 break;
164 case -ERESTARTSYS:
165 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
166 regs->r00 = -EINTR;
167 break;
168 }
169 /* Fall through */
170 case -ERESTARTNOINTR:
171 regs->r06 = regs->syscall_nr;
172 pt_set_elr(regs, pt_elr(regs) - 4);
173 regs->r00 = regs->restart_r0;
174 break;
175 default:
176 break;
177 }
178 }
179
180 /*
181 * Set up the stack frame; not doing the SA_SIGINFO thing. We
182 * only set up the rt_frame flavor.
183 */
184 /* If there was an error on setup, no signal was delivered. */
185 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
186
187 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
188 }
189
190 /*
191 * Called from return-from-event code.
192 */
do_signal(struct pt_regs * regs)193 void do_signal(struct pt_regs *regs)
194 {
195 struct ksignal ksig;
196
197 if (!user_mode(regs))
198 return;
199
200 if (get_signal(&ksig)) {
201 handle_signal(&ksig, regs);
202 return;
203 }
204
205 /*
206 * No (more) signals; if we came from a system call, handle the restart.
207 */
208
209 if (regs->syscall_nr >= 0) {
210 switch (regs->r00) {
211 case -ERESTARTNOHAND:
212 case -ERESTARTSYS:
213 case -ERESTARTNOINTR:
214 regs->r06 = regs->syscall_nr;
215 break;
216 case -ERESTART_RESTARTBLOCK:
217 regs->r06 = __NR_restart_syscall;
218 break;
219 default:
220 goto no_restart;
221 }
222 pt_set_elr(regs, pt_elr(regs) - 4);
223 regs->r00 = regs->restart_r0;
224 }
225
226 no_restart:
227 /* If there's no signal to deliver, put the saved sigmask back */
228 restore_saved_sigmask();
229 }
230
231 /*
232 * Architecture-specific wrappers for signal-related system calls
233 */
234
sys_rt_sigreturn(void)235 asmlinkage int sys_rt_sigreturn(void)
236 {
237 struct pt_regs *regs = current_pt_regs();
238 struct rt_sigframe __user *frame;
239 sigset_t blocked;
240
241 /* Always make any pending restarted system calls return -EINTR */
242 current->restart_block.fn = do_no_restart_syscall;
243
244 frame = (struct rt_sigframe __user *)pt_psp(regs);
245 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
246 goto badframe;
247 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
248 goto badframe;
249
250 set_current_blocked(&blocked);
251
252 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
253 goto badframe;
254
255 /* Restore the user's stack as well */
256 pt_psp(regs) = regs->r29;
257
258 regs->syscall_nr = -1;
259
260 if (restore_altstack(&frame->uc.uc_stack))
261 goto badframe;
262
263 return regs->r00;
264
265 badframe:
266 force_sig(SIGSEGV, current);
267 return 0;
268 }
269