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1// SPDX-License-Identifier: GPL-2.0
2// Copyright (C) 2005-2017 Andes Technology Corporation
3
4#include <linux/errno.h>
5#include <linux/signal.h>
6#include <linux/ptrace.h>
7#include <linux/personality.h>
8#include <linux/freezer.h>
9#include <linux/tracehook.h>
10#include <linux/uaccess.h>
11
12#include <asm/cacheflush.h>
13#include <asm/ucontext.h>
14#include <asm/unistd.h>
15
16#include <asm/ptrace.h>
17#include <asm/vdso.h>
18
19struct rt_sigframe {
20 struct siginfo info;
21 struct ucontext uc;
22};
23
24static int restore_sigframe(struct pt_regs *regs,
25 struct rt_sigframe __user * sf)
26{
27 sigset_t set;
28 int err;
29
30 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
31 if (err == 0) {
32 set_current_blocked(&set);
33 }
34
35 __get_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
36 __get_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
37 __get_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
38 __get_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
39 __get_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
40 __get_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
41 __get_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
42 __get_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
43 __get_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
44 __get_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
45 __get_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
46 __get_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
47 __get_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
48 __get_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
49 __get_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
50 __get_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
51 __get_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
52 __get_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
53 __get_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
54 __get_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
55 __get_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);
56 __get_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
57 __get_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
58 __get_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
59 __get_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
60 __get_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);
61
62 __get_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
63 __get_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
64 __get_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
65 __get_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
66 __get_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
67#if defined(CONFIG_HWZOL)
68 __get_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
69 __get_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
70 __get_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
71#endif
72
73 /*
74 * Avoid sys_rt_sigreturn() restarting.
75 */
76 forget_syscall(regs);
77 return err;
78}
79
80asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
81{
82 struct rt_sigframe __user *frame;
83
84 /* Always make any pending restarted system calls return -EINTR */
85 current->restart_block.fn = do_no_restart_syscall;
86
87 /*
88 * Since we stacked the signal on a 64-bit boundary,
89 * then 'sp' should be two-word aligned here. If it's
90 * not, then the user is trying to mess with us.
91 */
92 if (regs->sp & 7)
93 goto badframe;
94
95 frame = (struct rt_sigframe __user *)regs->sp;
96
97 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
98 goto badframe;
99
100 if (restore_sigframe(regs, frame))
101 goto badframe;
102
103 if (restore_altstack(&frame->uc.uc_stack))
104 goto badframe;
105
106 return regs->uregs[0];
107
108badframe:
109 force_sig(SIGSEGV, current);
110 return 0;
111}
112
113static int
114setup_sigframe(struct rt_sigframe __user * sf, struct pt_regs *regs,
115 sigset_t * set)
116{
117 int err = 0;
118
119 __put_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
120 __put_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
121 __put_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
122 __put_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
123 __put_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
124 __put_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
125 __put_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
126 __put_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
127 __put_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
128 __put_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
129 __put_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
130 __put_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
131 __put_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
132 __put_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
133 __put_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
134 __put_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
135 __put_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
136 __put_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
137 __put_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
138 __put_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
139 __put_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);
140
141 __put_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
142 __put_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
143 __put_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
144 __put_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
145 __put_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);
146 __put_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
147 __put_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
148 __put_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
149 __put_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
150 __put_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
151#if defined(CONFIG_HWZOL)
152 __put_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
153 __put_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
154 __put_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
155#endif
156
157 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no,
158 err);
159 __put_user_error(current->thread.error_code,
160 &sf->uc.uc_mcontext.error_code, err);
161 __put_user_error(current->thread.address,
162 &sf->uc.uc_mcontext.fault_address, err);
163 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
164
165 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
166
167 return err;
168}
169
170static inline void __user *get_sigframe(struct ksignal *ksig,
171 struct pt_regs *regs, int framesize)
172{
173 unsigned long sp;
174
175 /* Default to using normal stack */
176 sp = regs->sp;
177
178 /*
179 * If we are on the alternate signal stack and would overflow it, don't.
180 * Return an always-bogus address instead so we will die with SIGSEGV.
181 */
182 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
183 return (void __user __force *)(-1UL);
184
185 /* This is the X/Open sanctioned signal stack switching. */
186 sp = (sigsp(sp, ksig) - framesize);
187
188 /*
189 * nds32 mandates 8-byte alignment
190 */
191 sp &= ~0x7UL;
192
193 return (void __user *)sp;
194}
195
196static int
197setup_return(struct pt_regs *regs, struct ksignal *ksig, void __user * frame)
198{
199 unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
200 unsigned long retcode;
201
202 retcode = VDSO_SYMBOL(current->mm->context.vdso, rt_sigtramp);
203 regs->uregs[0] = ksig->sig;
204 regs->sp = (unsigned long)frame;
205 regs->lp = retcode;
206 regs->ipc = handler;
207
208 return 0;
209}
210
211static int
212setup_rt_frame(struct ksignal *ksig, sigset_t * set, struct pt_regs *regs)
213{
214 struct rt_sigframe __user *frame =
215 get_sigframe(ksig, regs, sizeof(*frame));
216 int err = 0;
217
218 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
219 return -EFAULT;
220
221 __put_user_error(0, &frame->uc.uc_flags, err);
222 __put_user_error(NULL, &frame->uc.uc_link, err);
223
224 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
225 err |= setup_sigframe(frame, regs, set);
226 if (err == 0) {
227 setup_return(regs, ksig, frame);
228 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
229 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
230 regs->uregs[1] = (unsigned long)&frame->info;
231 regs->uregs[2] = (unsigned long)&frame->uc;
232 }
233 }
234 return err;
235}
236
237/*
238 * OK, we're invoking a handler
239 */
240static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
241{
242 int ret;
243 sigset_t *oldset = sigmask_to_save();
244
245 if (in_syscall(regs)) {
246 /* Avoid additional syscall restarting via ret_slow_syscall. */
247 forget_syscall(regs);
248
249 switch (regs->uregs[0]) {
250 case -ERESTART_RESTARTBLOCK:
251 case -ERESTARTNOHAND:
252 regs->uregs[0] = -EINTR;
253 break;
254 case -ERESTARTSYS:
255 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
256 regs->uregs[0] = -EINTR;
257 break;
258 }
259 case -ERESTARTNOINTR:
260 regs->uregs[0] = regs->orig_r0;
261 regs->ipc -= 4;
262 break;
263 }
264 }
265 /*
266 * Set up the stack frame
267 */
268 ret = setup_rt_frame(ksig, oldset, regs);
269
270 signal_setup_done(ret, ksig, 0);
271}
272
273/*
274 * Note that 'init' is a special process: it doesn't get signals it doesn't
275 * want to handle. Thus you cannot kill init even with a SIGKILL even by
276 * mistake.
277 *
278 * Note that we go through the signals twice: once to check the signals that
279 * the kernel can handle, and then we build all the user-level signal handling
280 * stack-frames in one go after that.
281 */
282static void do_signal(struct pt_regs *regs)
283{
284 struct ksignal ksig;
285
286 if (get_signal(&ksig)) {
287 handle_signal(&ksig, regs);
288 return;
289 }
290
291 /*
292 * If we were from a system call, check for system call restarting...
293 */
294 if (in_syscall(regs)) {
295 /* Restart the system call - no handlers present */
296
297 /* Avoid additional syscall restarting via ret_slow_syscall. */
298 forget_syscall(regs);
299
300 switch (regs->uregs[0]) {
301 case -ERESTART_RESTARTBLOCK:
302 regs->uregs[15] = __NR_restart_syscall;
303 case -ERESTARTNOHAND:
304 case -ERESTARTSYS:
305 case -ERESTARTNOINTR:
306 regs->uregs[0] = regs->orig_r0;
307 regs->ipc -= 0x4;
308 break;
309 }
310 }
311 restore_saved_sigmask();
312}
313
314asmlinkage void
315do_notify_resume(struct pt_regs *regs, unsigned int thread_flags)
316{
317 if (thread_flags & _TIF_SIGPENDING)
318 do_signal(regs);
319
320 if (thread_flags & _TIF_NOTIFY_RESUME) {
321 clear_thread_flag(TIF_NOTIFY_RESUME);
322 tracehook_notify_resume(regs);
323 }
324}