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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
ac689eb7 JB |
2 | /* |
3 | * OpenRISC signal.c | |
4 | * | |
5 | * Linux architectural port borrowing liberally from similar works of | |
6 | * others. All original copyrights apply as per the original source | |
7 | * declaration. | |
8 | * | |
9 | * Modifications for the OpenRISC architecture: | |
10 | * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> | |
11 | * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> | |
ac689eb7 JB |
12 | */ |
13 | ||
14 | #include <linux/sched.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/signal.h> | |
19 | #include <linux/errno.h> | |
20 | #include <linux/wait.h> | |
21 | #include <linux/ptrace.h> | |
22 | #include <linux/unistd.h> | |
23 | #include <linux/stddef.h> | |
24 | #include <linux/tracehook.h> | |
25 | ||
26 | #include <asm/processor.h> | |
10f67dbf | 27 | #include <asm/syscall.h> |
ac689eb7 | 28 | #include <asm/ucontext.h> |
7c0f6ba6 | 29 | #include <linux/uaccess.h> |
ac689eb7 JB |
30 | |
31 | #define DEBUG_SIG 0 | |
32 | ||
ac689eb7 | 33 | struct rt_sigframe { |
ac689eb7 JB |
34 | struct siginfo info; |
35 | struct ucontext uc; | |
36 | unsigned char retcode[16]; /* trampoline code */ | |
37 | }; | |
38 | ||
10f67dbf JB |
39 | static int restore_sigcontext(struct pt_regs *regs, |
40 | struct sigcontext __user *sc) | |
ac689eb7 | 41 | { |
10f67dbf | 42 | int err = 0; |
ac689eb7 | 43 | |
10f67dbf | 44 | /* Always make any pending restarted system calls return -EINTR */ |
f56141e3 | 45 | current->restart_block.fn = do_no_restart_syscall; |
ac689eb7 | 46 | |
d7cb6667 JB |
47 | /* |
48 | * Restore the regs from &sc->regs. | |
96d4f267 | 49 | * (sc is already checked since the sigframe was |
ac689eb7 JB |
50 | * checked in sys_sigreturn previously) |
51 | */ | |
10f67dbf JB |
52 | err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long)); |
53 | err |= __copy_from_user(®s->pc, &sc->regs.pc, sizeof(unsigned long)); | |
54 | err |= __copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long)); | |
ac689eb7 JB |
55 | |
56 | /* make sure the SM-bit is cleared so user-mode cannot fool us */ | |
57 | regs->sr &= ~SPR_SR_SM; | |
58 | ||
10f67dbf JB |
59 | regs->orig_gpr11 = -1; /* Avoid syscall restart checks */ |
60 | ||
ac689eb7 JB |
61 | /* TODO: the other ports use regs->orig_XX to disable syscall checks |
62 | * after this completes, but we don't use that mechanism. maybe we can | |
63 | * use it now ? | |
64 | */ | |
65 | ||
66 | return err; | |
ac689eb7 JB |
67 | } |
68 | ||
69 | asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs) | |
70 | { | |
71 | struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp; | |
72 | sigset_t set; | |
ac689eb7 JB |
73 | |
74 | /* | |
75 | * Since we stacked the signal on a dword boundary, | |
76 | * then frame should be dword aligned here. If it's | |
77 | * not, then the user is trying to mess with us. | |
78 | */ | |
79 | if (((long)frame) & 3) | |
80 | goto badframe; | |
81 | ||
96d4f267 | 82 | if (!access_ok(frame, sizeof(*frame))) |
ac689eb7 JB |
83 | goto badframe; |
84 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
85 | goto badframe; | |
86 | ||
d8d4b20d | 87 | set_current_blocked(&set); |
ac689eb7 JB |
88 | |
89 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
90 | goto badframe; | |
91 | ||
faec5a96 | 92 | if (restore_altstack(&frame->uc.uc_stack)) |
d26654e5 | 93 | goto badframe; |
ac689eb7 JB |
94 | |
95 | return regs->gpr[11]; | |
96 | ||
97 | badframe: | |
98 | force_sig(SIGSEGV, current); | |
99 | return 0; | |
100 | } | |
101 | ||
102 | /* | |
103 | * Set up a signal frame. | |
104 | */ | |
105 | ||
10f67dbf | 106 | static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) |
ac689eb7 JB |
107 | { |
108 | int err = 0; | |
ac689eb7 | 109 | |
d7cb6667 | 110 | /* copy the regs */ |
10f67dbf JB |
111 | /* There should be no need to save callee-saved registers here... |
112 | * ...but we save them anyway. Revisit this | |
113 | */ | |
d7cb6667 JB |
114 | err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long)); |
115 | err |= __copy_to_user(&sc->regs.pc, ®s->pc, sizeof(unsigned long)); | |
116 | err |= __copy_to_user(&sc->regs.sr, ®s->sr, sizeof(unsigned long)); | |
ac689eb7 | 117 | |
ac689eb7 JB |
118 | return err; |
119 | } | |
120 | ||
121 | static inline unsigned long align_sigframe(unsigned long sp) | |
122 | { | |
123 | return sp & ~3UL; | |
124 | } | |
125 | ||
126 | /* | |
127 | * Work out where the signal frame should go. It's either on the user stack | |
128 | * or the alternate stack. | |
129 | */ | |
130 | ||
8e2beafa | 131 | static inline void __user *get_sigframe(struct ksignal *ksig, |
ac689eb7 JB |
132 | struct pt_regs *regs, size_t frame_size) |
133 | { | |
134 | unsigned long sp = regs->sp; | |
ac689eb7 JB |
135 | |
136 | /* redzone */ | |
137 | sp -= STACK_FRAME_OVERHEAD; | |
8e2beafa | 138 | sp = sigsp(sp, ksig); |
ac689eb7 JB |
139 | sp = align_sigframe(sp - frame_size); |
140 | ||
ac689eb7 JB |
141 | return (void __user *)sp; |
142 | } | |
143 | ||
144 | /* grab and setup a signal frame. | |
145 | * | |
146 | * basically we stack a lot of state info, and arrange for the | |
147 | * user-mode program to return to the kernel using either a | |
148 | * trampoline which performs the syscall sigreturn, or a provided | |
149 | * user-mode trampoline. | |
150 | */ | |
548dafe8 RW |
151 | static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, |
152 | struct pt_regs *regs) | |
ac689eb7 JB |
153 | { |
154 | struct rt_sigframe *frame; | |
155 | unsigned long return_ip; | |
156 | int err = 0; | |
157 | ||
8e2beafa | 158 | frame = get_sigframe(ksig, regs, sizeof(*frame)); |
548dafe8 | 159 | |
96d4f267 | 160 | if (!access_ok(frame, sizeof(*frame))) |
548dafe8 | 161 | return -EFAULT; |
ac689eb7 | 162 | |
10f67dbf | 163 | /* Create siginfo. */ |
548dafe8 RW |
164 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
165 | err |= copy_siginfo_to_user(&frame->info, &ksig->info); | |
ac689eb7 | 166 | |
10f67dbf | 167 | /* Create the ucontext. */ |
ac689eb7 JB |
168 | err |= __put_user(0, &frame->uc.uc_flags); |
169 | err |= __put_user(NULL, &frame->uc.uc_link); | |
faec5a96 | 170 | err |= __save_altstack(&frame->uc.uc_stack, regs->sp); |
10f67dbf | 171 | err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); |
ac689eb7 JB |
172 | |
173 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
174 | ||
175 | if (err) | |
548dafe8 | 176 | return -EFAULT; |
ac689eb7 JB |
177 | |
178 | /* trampoline - the desired return ip is the retcode itself */ | |
179 | return_ip = (unsigned long)&frame->retcode; | |
10f67dbf JB |
180 | /* This is: |
181 | l.ori r11,r0,__NR_sigreturn | |
182 | l.sys 1 | |
183 | */ | |
184 | err |= __put_user(0xa960, (short *)(frame->retcode + 0)); | |
185 | err |= __put_user(__NR_rt_sigreturn, (short *)(frame->retcode + 2)); | |
ac689eb7 JB |
186 | err |= __put_user(0x20000001, (unsigned long *)(frame->retcode + 4)); |
187 | err |= __put_user(0x15000000, (unsigned long *)(frame->retcode + 8)); | |
188 | ||
189 | if (err) | |
548dafe8 | 190 | return -EFAULT; |
ac689eb7 | 191 | |
ac689eb7 | 192 | /* Set up registers for signal handler */ |
548dafe8 | 193 | regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */ |
ac689eb7 | 194 | regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */ |
548dafe8 | 195 | regs->gpr[3] = (unsigned long)ksig->sig; /* arg 1: signo */ |
ac689eb7 JB |
196 | regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */ |
197 | regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */ | |
198 | ||
199 | /* actually move the usp to reflect the stacked frame */ | |
200 | regs->sp = (unsigned long)frame; | |
201 | ||
e933c70d | 202 | return 0; |
ac689eb7 JB |
203 | } |
204 | ||
39974d08 | 205 | static inline void |
548dafe8 | 206 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
ac689eb7 | 207 | { |
e933c70d MF |
208 | int ret; |
209 | ||
548dafe8 | 210 | ret = setup_rt_frame(ksig, sigmask_to_save(), regs); |
ac689eb7 | 211 | |
548dafe8 | 212 | signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); |
ac689eb7 JB |
213 | } |
214 | ||
215 | /* | |
216 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
217 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
218 | * mistake. | |
219 | * | |
220 | * Also note that the regs structure given here as an argument, is the latest | |
221 | * pushed pt_regs. It may or may not be the same as the first pushed registers | |
222 | * when the initial usermode->kernelmode transition took place. Therefore | |
223 | * we can use user_mode(regs) to see if we came directly from kernel or user | |
224 | * mode below. | |
225 | */ | |
226 | ||
10f67dbf | 227 | int do_signal(struct pt_regs *regs, int syscall) |
ac689eb7 | 228 | { |
548dafe8 | 229 | struct ksignal ksig; |
10f67dbf JB |
230 | unsigned long continue_addr = 0; |
231 | unsigned long restart_addr = 0; | |
232 | unsigned long retval = 0; | |
233 | int restart = 0; | |
234 | ||
235 | if (syscall) { | |
236 | continue_addr = regs->pc; | |
237 | restart_addr = continue_addr - 4; | |
238 | retval = regs->gpr[11]; | |
239 | ||
240 | /* | |
241 | * Setup syscall restart here so that a debugger will | |
242 | * see the already changed PC. | |
243 | */ | |
244 | switch (retval) { | |
ac689eb7 | 245 | case -ERESTART_RESTARTBLOCK: |
10f67dbf JB |
246 | restart = -2; |
247 | /* Fall through */ | |
ac689eb7 | 248 | case -ERESTARTNOHAND: |
ac689eb7 | 249 | case -ERESTARTSYS: |
ac689eb7 | 250 | case -ERESTARTNOINTR: |
10f67dbf JB |
251 | restart++; |
252 | regs->gpr[11] = regs->orig_gpr11; | |
253 | regs->pc = restart_addr; | |
ac689eb7 JB |
254 | break; |
255 | } | |
10f67dbf | 256 | } |
ac689eb7 | 257 | |
10f67dbf | 258 | /* |
548dafe8 RW |
259 | * Get the signal to deliver. During the call to get_signal the |
260 | * debugger may change all our registers so we may need to revert | |
261 | * the decision to restart the syscall; specifically, if the PC is | |
262 | * changed, don't restart the syscall. | |
10f67dbf | 263 | */ |
548dafe8 | 264 | if (get_signal(&ksig)) { |
10f67dbf JB |
265 | if (unlikely(restart) && regs->pc == restart_addr) { |
266 | if (retval == -ERESTARTNOHAND || | |
267 | retval == -ERESTART_RESTARTBLOCK | |
268 | || (retval == -ERESTARTSYS | |
548dafe8 | 269 | && !(ksig.ka.sa.sa_flags & SA_RESTART))) { |
10f67dbf JB |
270 | /* No automatic restart */ |
271 | regs->gpr[11] = -EINTR; | |
272 | regs->pc = continue_addr; | |
273 | } | |
ac689eb7 | 274 | } |
548dafe8 | 275 | handle_signal(&ksig, regs); |
10f67dbf JB |
276 | } else { |
277 | /* no handler */ | |
278 | restore_saved_sigmask(); | |
279 | /* | |
280 | * Restore pt_regs PC as syscall restart will be handled by | |
281 | * kernel without return to userspace | |
282 | */ | |
283 | if (unlikely(restart) && regs->pc == restart_addr) { | |
284 | regs->pc = continue_addr; | |
285 | return restart; | |
286 | } | |
ac689eb7 JB |
287 | } |
288 | ||
10f67dbf | 289 | return 0; |
ac689eb7 JB |
290 | } |
291 | ||
10f67dbf JB |
292 | asmlinkage int |
293 | do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) | |
ac689eb7 | 294 | { |
10f67dbf JB |
295 | do { |
296 | if (likely(thread_flags & _TIF_NEED_RESCHED)) { | |
297 | schedule(); | |
298 | } else { | |
299 | if (unlikely(!user_mode(regs))) | |
300 | return 0; | |
301 | local_irq_enable(); | |
302 | if (thread_flags & _TIF_SIGPENDING) { | |
303 | int restart = do_signal(regs, syscall); | |
304 | if (unlikely(restart)) { | |
305 | /* | |
306 | * Restart without handlers. | |
307 | * Deal with it without leaving | |
308 | * the kernel space. | |
309 | */ | |
310 | return restart; | |
311 | } | |
312 | syscall = 0; | |
313 | } else { | |
314 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
315 | tracehook_notify_resume(regs); | |
316 | } | |
317 | } | |
318 | local_irq_disable(); | |
319 | thread_flags = current_thread_info()->flags; | |
320 | } while (thread_flags & _TIF_WORK_MASK); | |
321 | return 0; | |
ac689eb7 | 322 | } |