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