1 /*
2 * Port on Texas Instruments TMS320C6x architecture
3 *
4 * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
5 * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
6 *
7 * Updated for 2.6.34: Mark Salter <msalter@redhat.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/uaccess.h>
16 #include <linux/syscalls.h>
17 #include <linux/tracehook.h>
18
19 #include <asm/ucontext.h>
20 #include <asm/cacheflush.h>
21
22
23 /*
24 * Do a signal return, undo the signal stack.
25 */
26
27 #define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
28
29 struct rt_sigframe {
30 struct siginfo __user *pinfo;
31 void __user *puc;
32 struct siginfo info;
33 struct ucontext uc;
34 unsigned long retcode[RETCODE_SIZE >> 2];
35 };
36
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc)37 static int restore_sigcontext(struct pt_regs *regs,
38 struct sigcontext __user *sc)
39 {
40 int err = 0;
41
42 /* The access_ok check was done by caller, so use __get_user here */
43 #define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x))
44
45 COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
46 COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
47 COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
48
49 COPY(a16); COPY(a17); COPY(a18); COPY(a19);
50 COPY(a20); COPY(a21); COPY(a22); COPY(a23);
51 COPY(a24); COPY(a25); COPY(a26); COPY(a27);
52 COPY(a28); COPY(a29); COPY(a30); COPY(a31);
53 COPY(b16); COPY(b17); COPY(b18); COPY(b19);
54 COPY(b20); COPY(b21); COPY(b22); COPY(b23);
55 COPY(b24); COPY(b25); COPY(b26); COPY(b27);
56 COPY(b28); COPY(b29); COPY(b30); COPY(b31);
57
58 COPY(csr); COPY(pc);
59
60 #undef COPY
61
62 return err;
63 }
64
do_rt_sigreturn(struct pt_regs * regs)65 asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
66 {
67 struct rt_sigframe __user *frame;
68 sigset_t set;
69
70 /* Always make any pending restarted system calls return -EINTR */
71 current->restart_block.fn = do_no_restart_syscall;
72
73 /*
74 * Since we stacked the signal on a dword boundary,
75 * 'sp' should be dword aligned here. If it's
76 * not, then the user is trying to mess with us.
77 */
78 if (regs->sp & 7)
79 goto badframe;
80
81 frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
82
83 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
84 goto badframe;
85 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
86 goto badframe;
87
88 set_current_blocked(&set);
89
90 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
91 goto badframe;
92
93 return regs->a4;
94
95 badframe:
96 force_sig(SIGSEGV, current);
97 return 0;
98 }
99
setup_sigcontext(struct sigcontext __user * sc,struct pt_regs * regs,unsigned long mask)100 static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
101 unsigned long mask)
102 {
103 int err = 0;
104
105 err |= __put_user(mask, &sc->sc_mask);
106
107 /* The access_ok check was done by caller, so use __put_user here */
108 #define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
109
110 COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
111 COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
112 COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
113
114 COPY(a16); COPY(a17); COPY(a18); COPY(a19);
115 COPY(a20); COPY(a21); COPY(a22); COPY(a23);
116 COPY(a24); COPY(a25); COPY(a26); COPY(a27);
117 COPY(a28); COPY(a29); COPY(a30); COPY(a31);
118 COPY(b16); COPY(b17); COPY(b18); COPY(b19);
119 COPY(b20); COPY(b21); COPY(b22); COPY(b23);
120 COPY(b24); COPY(b25); COPY(b26); COPY(b27);
121 COPY(b28); COPY(b29); COPY(b30); COPY(b31);
122
123 COPY(csr); COPY(pc);
124
125 #undef COPY
126
127 return err;
128 }
129
get_sigframe(struct ksignal * ksig,struct pt_regs * regs,unsigned long framesize)130 static inline void __user *get_sigframe(struct ksignal *ksig,
131 struct pt_regs *regs,
132 unsigned long framesize)
133 {
134 unsigned long sp = sigsp(regs->sp, ksig);
135
136 /*
137 * No matter what happens, 'sp' must be dword
138 * aligned. Otherwise, nasty things will happen
139 */
140 return (void __user *)((sp - framesize) & ~7);
141 }
142
setup_rt_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)143 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
144 struct pt_regs *regs)
145 {
146 struct rt_sigframe __user *frame;
147 unsigned long __user *retcode;
148 int err = 0;
149
150 frame = get_sigframe(ksig, regs, sizeof(*frame));
151
152 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
153 return -EFAULT;
154
155 err |= __put_user(&frame->info, &frame->pinfo);
156 err |= __put_user(&frame->uc, &frame->puc);
157 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
158
159 /* Clear all the bits of the ucontext we don't use. */
160 err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
161
162 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
163 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
164
165 /* Set up to return from userspace */
166 retcode = (unsigned long __user *) &frame->retcode;
167
168 /* The access_ok check was done above, so use __put_user here */
169 #define COPY(x) (err |= __put_user(x, retcode++))
170
171 COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
172 /* MVK __NR_rt_sigreturn,B0 */
173 COPY(0x10000000UL); /* SWE */
174 COPY(0x00006000UL); /* NOP 4 */
175 COPY(0x00006000UL); /* NOP 4 */
176 COPY(0x00006000UL); /* NOP 4 */
177 COPY(0x00006000UL); /* NOP 4 */
178 COPY(0x00006000UL); /* NOP 4 */
179 COPY(0x00006000UL); /* NOP 4 */
180 COPY(0x00006000UL); /* NOP 4 */
181
182 #undef COPY
183
184 if (err)
185 return -EFAULT;
186
187 flush_icache_range((unsigned long) &frame->retcode,
188 (unsigned long) &frame->retcode + RETCODE_SIZE);
189
190 retcode = (unsigned long __user *) &frame->retcode;
191
192 /* Change user context to branch to signal handler */
193 regs->sp = (unsigned long) frame - 8;
194 regs->b3 = (unsigned long) retcode;
195 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
196
197 /* Give the signal number to the handler */
198 regs->a4 = ksig->sig;
199
200 /*
201 * For realtime signals we must also set the second and third
202 * arguments for the signal handler.
203 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
204 */
205 regs->b4 = (unsigned long)&frame->info;
206 regs->a6 = (unsigned long)&frame->uc;
207
208 return 0;
209 }
210
211 static inline void
handle_restart(struct pt_regs * regs,struct k_sigaction * ka,int has_handler)212 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
213 {
214 switch (regs->a4) {
215 case -ERESTARTNOHAND:
216 if (!has_handler)
217 goto do_restart;
218 regs->a4 = -EINTR;
219 break;
220
221 case -ERESTARTSYS:
222 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
223 regs->a4 = -EINTR;
224 break;
225 }
226 /* fallthrough */
227 case -ERESTARTNOINTR:
228 do_restart:
229 regs->a4 = regs->orig_a4;
230 regs->pc -= 4;
231 break;
232 }
233 }
234
235 /*
236 * handle the actual delivery of a signal to userspace
237 */
handle_signal(struct ksignal * ksig,struct pt_regs * regs,int syscall)238 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
239 int syscall)
240 {
241 int ret;
242
243 /* Are we from a system call? */
244 if (syscall) {
245 /* If so, check system call restarting.. */
246 switch (regs->a4) {
247 case -ERESTART_RESTARTBLOCK:
248 case -ERESTARTNOHAND:
249 regs->a4 = -EINTR;
250 break;
251
252 case -ERESTARTSYS:
253 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
254 regs->a4 = -EINTR;
255 break;
256 }
257
258 /* fallthrough */
259 case -ERESTARTNOINTR:
260 regs->a4 = regs->orig_a4;
261 regs->pc -= 4;
262 }
263 }
264
265 /* Set up the stack frame */
266 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
267 signal_setup_done(ret, ksig, 0);
268 }
269
270 /*
271 * handle a potential signal
272 */
do_signal(struct pt_regs * regs,int syscall)273 static void do_signal(struct pt_regs *regs, int syscall)
274 {
275 struct ksignal ksig;
276
277 /* we want the common case to go fast, which is why we may in certain
278 * cases get here from kernel mode */
279 if (!user_mode(regs))
280 return;
281
282 if (get_signal(&ksig)) {
283 handle_signal(&ksig, regs, syscall);
284 return;
285 }
286
287 /* did we come from a system call? */
288 if (syscall) {
289 /* restart the system call - no handlers present */
290 switch (regs->a4) {
291 case -ERESTARTNOHAND:
292 case -ERESTARTSYS:
293 case -ERESTARTNOINTR:
294 regs->a4 = regs->orig_a4;
295 regs->pc -= 4;
296 break;
297
298 case -ERESTART_RESTARTBLOCK:
299 regs->a4 = regs->orig_a4;
300 regs->b0 = __NR_restart_syscall;
301 regs->pc -= 4;
302 break;
303 }
304 }
305
306 /* if there's no signal to deliver, we just put the saved sigmask
307 * back */
308 restore_saved_sigmask();
309 }
310
311 /*
312 * notification of userspace execution resumption
313 * - triggered by current->work.notify_resume
314 */
do_notify_resume(struct pt_regs * regs,u32 thread_info_flags,int syscall)315 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
316 int syscall)
317 {
318 /* deal with pending signal delivery */
319 if (thread_info_flags & (1 << TIF_SIGPENDING))
320 do_signal(regs, syscall);
321
322 if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
323 clear_thread_flag(TIF_NOTIFY_RESUME);
324 tracehook_notify_resume(regs);
325 }
326 }
327