1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Port on Texas Instruments TMS320C6x architecture
4 *
5 * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
6 * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
7 *
8 * Updated for 2.6.34: Mark Salter <msalter@redhat.com>
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/uaccess.h>
13 #include <linux/syscalls.h>
14 #include <linux/tracehook.h>
15
16 #include <asm/asm-offsets.h>
17 #include <asm/ucontext.h>
18 #include <asm/cacheflush.h>
19
20
21 /*
22 * Do a signal return, undo the signal stack.
23 */
24
25 #define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
26
27 struct rt_sigframe {
28 struct siginfo __user *pinfo;
29 void __user *puc;
30 struct siginfo info;
31 struct ucontext uc;
32 unsigned long retcode[RETCODE_SIZE >> 2];
33 };
34
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc)35 static int restore_sigcontext(struct pt_regs *regs,
36 struct sigcontext __user *sc)
37 {
38 int err = 0;
39
40 /* The access_ok check was done by caller, so use __get_user here */
41 #define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x))
42
43 COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
44 COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
45 COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
46
47 COPY(a16); COPY(a17); COPY(a18); COPY(a19);
48 COPY(a20); COPY(a21); COPY(a22); COPY(a23);
49 COPY(a24); COPY(a25); COPY(a26); COPY(a27);
50 COPY(a28); COPY(a29); COPY(a30); COPY(a31);
51 COPY(b16); COPY(b17); COPY(b18); COPY(b19);
52 COPY(b20); COPY(b21); COPY(b22); COPY(b23);
53 COPY(b24); COPY(b25); COPY(b26); COPY(b27);
54 COPY(b28); COPY(b29); COPY(b30); COPY(b31);
55
56 COPY(csr); COPY(pc);
57
58 #undef COPY
59
60 return err;
61 }
62
do_rt_sigreturn(struct pt_regs * regs)63 asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
64 {
65 struct rt_sigframe __user *frame;
66 sigset_t set;
67
68 /* Always make any pending restarted system calls return -EINTR */
69 current->restart_block.fn = do_no_restart_syscall;
70
71 /*
72 * Since we stacked the signal on a dword boundary,
73 * 'sp' should be dword aligned here. If it's
74 * not, then the user is trying to mess with us.
75 */
76 if (regs->sp & 7)
77 goto badframe;
78
79 frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
80
81 if (!access_ok(frame, sizeof(*frame)))
82 goto badframe;
83 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
84 goto badframe;
85
86 set_current_blocked(&set);
87
88 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
89 goto badframe;
90
91 return regs->a4;
92
93 badframe:
94 force_sig(SIGSEGV);
95 return 0;
96 }
97
setup_sigcontext(struct sigcontext __user * sc,struct pt_regs * regs,unsigned long mask)98 static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
99 unsigned long mask)
100 {
101 int err = 0;
102
103 err |= __put_user(mask, &sc->sc_mask);
104
105 /* The access_ok check was done by caller, so use __put_user here */
106 #define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
107
108 COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
109 COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
110 COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
111
112 COPY(a16); COPY(a17); COPY(a18); COPY(a19);
113 COPY(a20); COPY(a21); COPY(a22); COPY(a23);
114 COPY(a24); COPY(a25); COPY(a26); COPY(a27);
115 COPY(a28); COPY(a29); COPY(a30); COPY(a31);
116 COPY(b16); COPY(b17); COPY(b18); COPY(b19);
117 COPY(b20); COPY(b21); COPY(b22); COPY(b23);
118 COPY(b24); COPY(b25); COPY(b26); COPY(b27);
119 COPY(b28); COPY(b29); COPY(b30); COPY(b31);
120
121 COPY(csr); COPY(pc);
122
123 #undef COPY
124
125 return err;
126 }
127
get_sigframe(struct ksignal * ksig,struct pt_regs * regs,unsigned long framesize)128 static inline void __user *get_sigframe(struct ksignal *ksig,
129 struct pt_regs *regs,
130 unsigned long framesize)
131 {
132 unsigned long sp = sigsp(regs->sp, ksig);
133
134 /*
135 * No matter what happens, 'sp' must be dword
136 * aligned. Otherwise, nasty things will happen
137 */
138 return (void __user *)((sp - framesize) & ~7);
139 }
140
setup_rt_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)141 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
142 struct pt_regs *regs)
143 {
144 struct rt_sigframe __user *frame;
145 unsigned long __user *retcode;
146 int err = 0;
147
148 frame = get_sigframe(ksig, regs, sizeof(*frame));
149
150 if (!access_ok(frame, sizeof(*frame)))
151 return -EFAULT;
152
153 err |= __put_user(&frame->info, &frame->pinfo);
154 err |= __put_user(&frame->uc, &frame->puc);
155 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
156
157 /* Clear all the bits of the ucontext we don't use. */
158 err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
159
160 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
161 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
162
163 /* Set up to return from userspace */
164 retcode = (unsigned long __user *) &frame->retcode;
165
166 /* The access_ok check was done above, so use __put_user here */
167 #define COPY(x) (err |= __put_user(x, retcode++))
168
169 COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
170 /* MVK __NR_rt_sigreturn,B0 */
171 COPY(0x10000000UL); /* SWE */
172 COPY(0x00006000UL); /* NOP 4 */
173 COPY(0x00006000UL); /* NOP 4 */
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
180 #undef COPY
181
182 if (err)
183 return -EFAULT;
184
185 flush_icache_range((unsigned long) &frame->retcode,
186 (unsigned long) &frame->retcode + RETCODE_SIZE);
187
188 retcode = (unsigned long __user *) &frame->retcode;
189
190 /* Change user context to branch to signal handler */
191 regs->sp = (unsigned long) frame - 8;
192 regs->b3 = (unsigned long) retcode;
193 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
194
195 /* Give the signal number to the handler */
196 regs->a4 = ksig->sig;
197
198 /*
199 * For realtime signals we must also set the second and third
200 * arguments for the signal handler.
201 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
202 */
203 regs->b4 = (unsigned long)&frame->info;
204 regs->a6 = (unsigned long)&frame->uc;
205
206 return 0;
207 }
208
209 static inline void
handle_restart(struct pt_regs * regs,struct k_sigaction * ka,int has_handler)210 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
211 {
212 switch (regs->a4) {
213 case -ERESTARTNOHAND:
214 if (!has_handler)
215 goto do_restart;
216 regs->a4 = -EINTR;
217 break;
218
219 case -ERESTARTSYS:
220 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
221 regs->a4 = -EINTR;
222 break;
223 }
224 fallthrough;
225 case -ERESTARTNOINTR:
226 do_restart:
227 regs->a4 = regs->orig_a4;
228 regs->pc -= 4;
229 break;
230 }
231 }
232
233 /*
234 * handle the actual delivery of a signal to userspace
235 */
handle_signal(struct ksignal * ksig,struct pt_regs * regs,int syscall)236 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
237 int syscall)
238 {
239 int ret;
240
241 /* Are we from a system call? */
242 if (syscall) {
243 /* If so, check system call restarting.. */
244 switch (regs->a4) {
245 case -ERESTART_RESTARTBLOCK:
246 case -ERESTARTNOHAND:
247 regs->a4 = -EINTR;
248 break;
249
250 case -ERESTARTSYS:
251 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
252 regs->a4 = -EINTR;
253 break;
254 }
255
256 fallthrough;
257 case -ERESTARTNOINTR:
258 regs->a4 = regs->orig_a4;
259 regs->pc -= 4;
260 }
261 }
262
263 /* Set up the stack frame */
264 ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
265 signal_setup_done(ret, ksig, 0);
266 }
267
268 /*
269 * handle a potential signal
270 */
do_signal(struct pt_regs * regs,int syscall)271 static void do_signal(struct pt_regs *regs, int syscall)
272 {
273 struct ksignal ksig;
274
275 /* we want the common case to go fast, which is why we may in certain
276 * cases get here from kernel mode */
277 if (!user_mode(regs))
278 return;
279
280 if (get_signal(&ksig)) {
281 handle_signal(&ksig, regs, syscall);
282 return;
283 }
284
285 /* did we come from a system call? */
286 if (syscall) {
287 /* restart the system call - no handlers present */
288 switch (regs->a4) {
289 case -ERESTARTNOHAND:
290 case -ERESTARTSYS:
291 case -ERESTARTNOINTR:
292 regs->a4 = regs->orig_a4;
293 regs->pc -= 4;
294 break;
295
296 case -ERESTART_RESTARTBLOCK:
297 regs->a4 = regs->orig_a4;
298 regs->b0 = __NR_restart_syscall;
299 regs->pc -= 4;
300 break;
301 }
302 }
303
304 /* if there's no signal to deliver, we just put the saved sigmask
305 * back */
306 restore_saved_sigmask();
307 }
308
309 /*
310 * notification of userspace execution resumption
311 * - triggered by current->work.notify_resume
312 */
do_notify_resume(struct pt_regs * regs,u32 thread_info_flags,int syscall)313 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
314 int syscall)
315 {
316 /* deal with pending signal delivery */
317 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
318 do_signal(regs, syscall);
319
320 if (thread_info_flags & (1 << TIF_NOTIFY_RESUME))
321 tracehook_notify_resume(regs);
322 }
323