1 /*
2 * linux/arch/unicore32/kernel/signal.c
3 *
4 * Code specific to PKUnity SoC and UniCore ISA
5 *
6 * Copyright (C) 2001-2010 GUAN Xue-tao
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12 #include <linux/errno.h>
13 #include <linux/signal.h>
14 #include <linux/personality.h>
15 #include <linux/uaccess.h>
16 #include <linux/tracehook.h>
17 #include <linux/elf.h>
18 #include <linux/unistd.h>
19
20 #include <asm/cacheflush.h>
21 #include <asm/ucontext.h>
22
23 /*
24 * For UniCore syscalls, we encode the syscall number into the instruction.
25 */
26 #define SWI_SYS_SIGRETURN (0xff000000) /* error number for new abi */
27 #define SWI_SYS_RT_SIGRETURN (0xff000000 | (__NR_rt_sigreturn))
28 #define SWI_SYS_RESTART (0xff000000 | (__NR_restart_syscall))
29
30 #define KERN_SIGRETURN_CODE (KUSER_VECPAGE_BASE + 0x00000500)
31 #define KERN_RESTART_CODE (KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))
32
33 const unsigned long sigreturn_codes[3] = {
34 SWI_SYS_SIGRETURN, SWI_SYS_RT_SIGRETURN,
35 };
36
37 const unsigned long syscall_restart_code[2] = {
38 SWI_SYS_RESTART, /* swi __NR_restart_syscall */
39 0x69efc004, /* ldr pc, [sp], #4 */
40 };
41
42 /*
43 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
44 */
45 struct sigframe {
46 struct ucontext uc;
47 unsigned long retcode[2];
48 };
49
50 struct rt_sigframe {
51 struct siginfo info;
52 struct sigframe sig;
53 };
54
restore_sigframe(struct pt_regs * regs,struct sigframe __user * sf)55 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
56 {
57 sigset_t set;
58 int err;
59
60 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
61 if (err == 0)
62 set_current_blocked(&set);
63
64 err |= __get_user(regs->UCreg_00, &sf->uc.uc_mcontext.regs.UCreg_00);
65 err |= __get_user(regs->UCreg_01, &sf->uc.uc_mcontext.regs.UCreg_01);
66 err |= __get_user(regs->UCreg_02, &sf->uc.uc_mcontext.regs.UCreg_02);
67 err |= __get_user(regs->UCreg_03, &sf->uc.uc_mcontext.regs.UCreg_03);
68 err |= __get_user(regs->UCreg_04, &sf->uc.uc_mcontext.regs.UCreg_04);
69 err |= __get_user(regs->UCreg_05, &sf->uc.uc_mcontext.regs.UCreg_05);
70 err |= __get_user(regs->UCreg_06, &sf->uc.uc_mcontext.regs.UCreg_06);
71 err |= __get_user(regs->UCreg_07, &sf->uc.uc_mcontext.regs.UCreg_07);
72 err |= __get_user(regs->UCreg_08, &sf->uc.uc_mcontext.regs.UCreg_08);
73 err |= __get_user(regs->UCreg_09, &sf->uc.uc_mcontext.regs.UCreg_09);
74 err |= __get_user(regs->UCreg_10, &sf->uc.uc_mcontext.regs.UCreg_10);
75 err |= __get_user(regs->UCreg_11, &sf->uc.uc_mcontext.regs.UCreg_11);
76 err |= __get_user(regs->UCreg_12, &sf->uc.uc_mcontext.regs.UCreg_12);
77 err |= __get_user(regs->UCreg_13, &sf->uc.uc_mcontext.regs.UCreg_13);
78 err |= __get_user(regs->UCreg_14, &sf->uc.uc_mcontext.regs.UCreg_14);
79 err |= __get_user(regs->UCreg_15, &sf->uc.uc_mcontext.regs.UCreg_15);
80 err |= __get_user(regs->UCreg_16, &sf->uc.uc_mcontext.regs.UCreg_16);
81 err |= __get_user(regs->UCreg_17, &sf->uc.uc_mcontext.regs.UCreg_17);
82 err |= __get_user(regs->UCreg_18, &sf->uc.uc_mcontext.regs.UCreg_18);
83 err |= __get_user(regs->UCreg_19, &sf->uc.uc_mcontext.regs.UCreg_19);
84 err |= __get_user(regs->UCreg_20, &sf->uc.uc_mcontext.regs.UCreg_20);
85 err |= __get_user(regs->UCreg_21, &sf->uc.uc_mcontext.regs.UCreg_21);
86 err |= __get_user(regs->UCreg_22, &sf->uc.uc_mcontext.regs.UCreg_22);
87 err |= __get_user(regs->UCreg_23, &sf->uc.uc_mcontext.regs.UCreg_23);
88 err |= __get_user(regs->UCreg_24, &sf->uc.uc_mcontext.regs.UCreg_24);
89 err |= __get_user(regs->UCreg_25, &sf->uc.uc_mcontext.regs.UCreg_25);
90 err |= __get_user(regs->UCreg_26, &sf->uc.uc_mcontext.regs.UCreg_26);
91 err |= __get_user(regs->UCreg_fp, &sf->uc.uc_mcontext.regs.UCreg_fp);
92 err |= __get_user(regs->UCreg_ip, &sf->uc.uc_mcontext.regs.UCreg_ip);
93 err |= __get_user(regs->UCreg_sp, &sf->uc.uc_mcontext.regs.UCreg_sp);
94 err |= __get_user(regs->UCreg_lr, &sf->uc.uc_mcontext.regs.UCreg_lr);
95 err |= __get_user(regs->UCreg_pc, &sf->uc.uc_mcontext.regs.UCreg_pc);
96 err |= __get_user(regs->UCreg_asr, &sf->uc.uc_mcontext.regs.UCreg_asr);
97
98 err |= !valid_user_regs(regs);
99
100 return err;
101 }
102
__sys_rt_sigreturn(struct pt_regs * regs)103 asmlinkage int __sys_rt_sigreturn(struct pt_regs *regs)
104 {
105 struct rt_sigframe __user *frame;
106
107 /* Always make any pending restarted system calls return -EINTR */
108 current->restart_block.fn = do_no_restart_syscall;
109
110 /*
111 * Since we stacked the signal on a 64-bit boundary,
112 * then 'sp' should be word aligned here. If it's
113 * not, then the user is trying to mess with us.
114 */
115 if (regs->UCreg_sp & 7)
116 goto badframe;
117
118 frame = (struct rt_sigframe __user *)regs->UCreg_sp;
119
120 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
121 goto badframe;
122
123 if (restore_sigframe(regs, &frame->sig))
124 goto badframe;
125
126 if (restore_altstack(&frame->sig.uc.uc_stack))
127 goto badframe;
128
129 return regs->UCreg_00;
130
131 badframe:
132 force_sig(SIGSEGV, current);
133 return 0;
134 }
135
setup_sigframe(struct sigframe __user * sf,struct pt_regs * regs,sigset_t * set)136 static int setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs,
137 sigset_t *set)
138 {
139 int err = 0;
140
141 err |= __put_user(regs->UCreg_00, &sf->uc.uc_mcontext.regs.UCreg_00);
142 err |= __put_user(regs->UCreg_01, &sf->uc.uc_mcontext.regs.UCreg_01);
143 err |= __put_user(regs->UCreg_02, &sf->uc.uc_mcontext.regs.UCreg_02);
144 err |= __put_user(regs->UCreg_03, &sf->uc.uc_mcontext.regs.UCreg_03);
145 err |= __put_user(regs->UCreg_04, &sf->uc.uc_mcontext.regs.UCreg_04);
146 err |= __put_user(regs->UCreg_05, &sf->uc.uc_mcontext.regs.UCreg_05);
147 err |= __put_user(regs->UCreg_06, &sf->uc.uc_mcontext.regs.UCreg_06);
148 err |= __put_user(regs->UCreg_07, &sf->uc.uc_mcontext.regs.UCreg_07);
149 err |= __put_user(regs->UCreg_08, &sf->uc.uc_mcontext.regs.UCreg_08);
150 err |= __put_user(regs->UCreg_09, &sf->uc.uc_mcontext.regs.UCreg_09);
151 err |= __put_user(regs->UCreg_10, &sf->uc.uc_mcontext.regs.UCreg_10);
152 err |= __put_user(regs->UCreg_11, &sf->uc.uc_mcontext.regs.UCreg_11);
153 err |= __put_user(regs->UCreg_12, &sf->uc.uc_mcontext.regs.UCreg_12);
154 err |= __put_user(regs->UCreg_13, &sf->uc.uc_mcontext.regs.UCreg_13);
155 err |= __put_user(regs->UCreg_14, &sf->uc.uc_mcontext.regs.UCreg_14);
156 err |= __put_user(regs->UCreg_15, &sf->uc.uc_mcontext.regs.UCreg_15);
157 err |= __put_user(regs->UCreg_16, &sf->uc.uc_mcontext.regs.UCreg_16);
158 err |= __put_user(regs->UCreg_17, &sf->uc.uc_mcontext.regs.UCreg_17);
159 err |= __put_user(regs->UCreg_18, &sf->uc.uc_mcontext.regs.UCreg_18);
160 err |= __put_user(regs->UCreg_19, &sf->uc.uc_mcontext.regs.UCreg_19);
161 err |= __put_user(regs->UCreg_20, &sf->uc.uc_mcontext.regs.UCreg_20);
162 err |= __put_user(regs->UCreg_21, &sf->uc.uc_mcontext.regs.UCreg_21);
163 err |= __put_user(regs->UCreg_22, &sf->uc.uc_mcontext.regs.UCreg_22);
164 err |= __put_user(regs->UCreg_23, &sf->uc.uc_mcontext.regs.UCreg_23);
165 err |= __put_user(regs->UCreg_24, &sf->uc.uc_mcontext.regs.UCreg_24);
166 err |= __put_user(regs->UCreg_25, &sf->uc.uc_mcontext.regs.UCreg_25);
167 err |= __put_user(regs->UCreg_26, &sf->uc.uc_mcontext.regs.UCreg_26);
168 err |= __put_user(regs->UCreg_fp, &sf->uc.uc_mcontext.regs.UCreg_fp);
169 err |= __put_user(regs->UCreg_ip, &sf->uc.uc_mcontext.regs.UCreg_ip);
170 err |= __put_user(regs->UCreg_sp, &sf->uc.uc_mcontext.regs.UCreg_sp);
171 err |= __put_user(regs->UCreg_lr, &sf->uc.uc_mcontext.regs.UCreg_lr);
172 err |= __put_user(regs->UCreg_pc, &sf->uc.uc_mcontext.regs.UCreg_pc);
173 err |= __put_user(regs->UCreg_asr, &sf->uc.uc_mcontext.regs.UCreg_asr);
174
175 err |= __put_user(current->thread.trap_no,
176 &sf->uc.uc_mcontext.trap_no);
177 err |= __put_user(current->thread.error_code,
178 &sf->uc.uc_mcontext.error_code);
179 err |= __put_user(current->thread.address,
180 &sf->uc.uc_mcontext.fault_address);
181 err |= __put_user(set->sig[0], &sf->uc.uc_mcontext.oldmask);
182
183 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
184
185 return err;
186 }
187
get_sigframe(struct k_sigaction * ka,struct pt_regs * regs,int framesize)188 static inline void __user *get_sigframe(struct k_sigaction *ka,
189 struct pt_regs *regs, int framesize)
190 {
191 unsigned long sp = regs->UCreg_sp;
192 void __user *frame;
193
194 /*
195 * This is the X/Open sanctioned signal stack switching.
196 */
197 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
198 sp = current->sas_ss_sp + current->sas_ss_size;
199
200 /*
201 * ATPCS B01 mandates 8-byte alignment
202 */
203 frame = (void __user *)((sp - framesize) & ~7);
204
205 /*
206 * Check that we can actually write to the signal frame.
207 */
208 if (!access_ok(VERIFY_WRITE, frame, framesize))
209 frame = NULL;
210
211 return frame;
212 }
213
setup_return(struct pt_regs * regs,struct k_sigaction * ka,unsigned long __user * rc,void __user * frame,int usig)214 static int setup_return(struct pt_regs *regs, struct k_sigaction *ka,
215 unsigned long __user *rc, void __user *frame, int usig)
216 {
217 unsigned long handler = (unsigned long)ka->sa.sa_handler;
218 unsigned long retcode;
219 unsigned long asr = regs->UCreg_asr & ~PSR_f;
220
221 unsigned int idx = 0;
222
223 if (ka->sa.sa_flags & SA_SIGINFO)
224 idx += 1;
225
226 if (__put_user(sigreturn_codes[idx], rc) ||
227 __put_user(sigreturn_codes[idx+1], rc+1))
228 return 1;
229
230 retcode = KERN_SIGRETURN_CODE + (idx << 2);
231
232 regs->UCreg_00 = usig;
233 regs->UCreg_sp = (unsigned long)frame;
234 regs->UCreg_lr = retcode;
235 regs->UCreg_pc = handler;
236 regs->UCreg_asr = asr;
237
238 return 0;
239 }
240
setup_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)241 static int setup_frame(struct ksignal *ksig, sigset_t *set,
242 struct pt_regs *regs)
243 {
244 struct sigframe __user *frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
245 int err = 0;
246
247 if (!frame)
248 return 1;
249
250 /*
251 * Set uc.uc_flags to a value which sc.trap_no would never have.
252 */
253 err |= __put_user(0x5ac3c35a, &frame->uc.uc_flags);
254
255 err |= setup_sigframe(frame, regs, set);
256 if (err == 0)
257 err |= setup_return(regs, &ksig->ka, frame->retcode, frame,
258 ksig->sig);
259
260 return err;
261 }
262
setup_rt_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)263 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
264 struct pt_regs *regs)
265 {
266 struct rt_sigframe __user *frame =
267 get_sigframe(&ksig->ka, regs, sizeof(*frame));
268 int err = 0;
269
270 if (!frame)
271 return 1;
272
273 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
274
275 err |= __put_user(0, &frame->sig.uc.uc_flags);
276 err |= __put_user(NULL, &frame->sig.uc.uc_link);
277 err |= __save_altstack(&frame->sig.uc.uc_stack, regs->UCreg_sp);
278 err |= setup_sigframe(&frame->sig, regs, set);
279 if (err == 0)
280 err |= setup_return(regs, &ksig->ka, frame->sig.retcode, frame,
281 ksig->sig);
282
283 if (err == 0) {
284 /*
285 * For realtime signals we must also set the second and third
286 * arguments for the signal handler.
287 */
288 regs->UCreg_01 = (unsigned long)&frame->info;
289 regs->UCreg_02 = (unsigned long)&frame->sig.uc;
290 }
291
292 return err;
293 }
294
setup_syscall_restart(struct pt_regs * regs)295 static inline void setup_syscall_restart(struct pt_regs *regs)
296 {
297 regs->UCreg_00 = regs->UCreg_ORIG_00;
298 regs->UCreg_pc -= 4;
299 }
300
301 /*
302 * OK, we're invoking a handler
303 */
handle_signal(struct ksignal * ksig,struct pt_regs * regs,int syscall)304 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
305 int syscall)
306 {
307 struct thread_info *thread = current_thread_info();
308 sigset_t *oldset = sigmask_to_save();
309 int usig = ksig->sig;
310 int ret;
311
312 /*
313 * If we were from a system call, check for system call restarting...
314 */
315 if (syscall) {
316 switch (regs->UCreg_00) {
317 case -ERESTART_RESTARTBLOCK:
318 case -ERESTARTNOHAND:
319 regs->UCreg_00 = -EINTR;
320 break;
321 case -ERESTARTSYS:
322 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
323 regs->UCreg_00 = -EINTR;
324 break;
325 }
326 /* fallthrough */
327 case -ERESTARTNOINTR:
328 setup_syscall_restart(regs);
329 }
330 }
331
332 /*
333 * Set up the stack frame
334 */
335 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
336 ret = setup_rt_frame(ksig, oldset, regs);
337 else
338 ret = setup_frame(ksig, oldset, regs);
339
340 /*
341 * Check that the resulting registers are actually sane.
342 */
343 ret |= !valid_user_regs(regs);
344
345 signal_setup_done(ret, ksig, 0);
346 }
347
348 /*
349 * Note that 'init' is a special process: it doesn't get signals it doesn't
350 * want to handle. Thus you cannot kill init even with a SIGKILL even by
351 * mistake.
352 *
353 * Note that we go through the signals twice: once to check the signals that
354 * the kernel can handle, and then we build all the user-level signal handling
355 * stack-frames in one go after that.
356 */
do_signal(struct pt_regs * regs,int syscall)357 static void do_signal(struct pt_regs *regs, int syscall)
358 {
359 struct ksignal ksig;
360
361 /*
362 * We want the common case to go fast, which
363 * is why we may in certain cases get here from
364 * kernel mode. Just return without doing anything
365 * if so.
366 */
367 if (!user_mode(regs))
368 return;
369
370 if (get_signal(&ksig)) {
371 handle_signal(&ksig, regs, syscall);
372 return;
373 }
374
375 /*
376 * No signal to deliver to the process - restart the syscall.
377 */
378 if (syscall) {
379 if (regs->UCreg_00 == -ERESTART_RESTARTBLOCK) {
380 u32 __user *usp;
381
382 regs->UCreg_sp -= 4;
383 usp = (u32 __user *)regs->UCreg_sp;
384
385 if (put_user(regs->UCreg_pc, usp) == 0) {
386 regs->UCreg_pc = KERN_RESTART_CODE;
387 } else {
388 regs->UCreg_sp += 4;
389 force_sigsegv(0, current);
390 }
391 }
392 if (regs->UCreg_00 == -ERESTARTNOHAND ||
393 regs->UCreg_00 == -ERESTARTSYS ||
394 regs->UCreg_00 == -ERESTARTNOINTR) {
395 setup_syscall_restart(regs);
396 }
397 }
398 /* If there's no signal to deliver, we just put the saved
399 * sigmask back.
400 */
401 restore_saved_sigmask();
402 }
403
do_notify_resume(struct pt_regs * regs,unsigned int thread_flags,int syscall)404 asmlinkage void do_notify_resume(struct pt_regs *regs,
405 unsigned int thread_flags, int syscall)
406 {
407 if (thread_flags & _TIF_SIGPENDING)
408 do_signal(regs, syscall);
409
410 if (thread_flags & _TIF_NOTIFY_RESUME) {
411 clear_thread_flag(TIF_NOTIFY_RESUME);
412 tracehook_notify_resume(regs);
413 }
414 }
415
416 /*
417 * Copy signal return handlers into the vector page, and
418 * set sigreturn to be a pointer to these.
419 */
early_signal_init(void)420 void __init early_signal_init(void)
421 {
422 memcpy((void *)kuser_vecpage_to_vectors(KERN_SIGRETURN_CODE),
423 sigreturn_codes, sizeof(sigreturn_codes));
424 memcpy((void *)kuser_vecpage_to_vectors(KERN_RESTART_CODE),
425 syscall_restart_code, sizeof(syscall_restart_code));
426 /* Need not to flush icache, since early_trap_init will do it last. */
427 }
428