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ac689eb7 JB |
1 | /* |
2 | * OpenRISC signal.c | |
3 | * | |
4 | * Linux architectural port borrowing liberally from similar works of | |
5 | * others. All original copyrights apply as per the original source | |
6 | * declaration. | |
7 | * | |
8 | * Modifications for the OpenRISC architecture: | |
9 | * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> | |
10 | * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version | |
15 | * 2 of the License, or (at your option) any later version. | |
16 | */ | |
17 | ||
18 | #include <linux/sched.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/smp.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/signal.h> | |
23 | #include <linux/errno.h> | |
24 | #include <linux/wait.h> | |
25 | #include <linux/ptrace.h> | |
26 | #include <linux/unistd.h> | |
27 | #include <linux/stddef.h> | |
28 | #include <linux/tracehook.h> | |
29 | ||
30 | #include <asm/processor.h> | |
10f67dbf | 31 | #include <asm/syscall.h> |
ac689eb7 | 32 | #include <asm/ucontext.h> |
7c0f6ba6 | 33 | #include <linux/uaccess.h> |
ac689eb7 JB |
34 | |
35 | #define DEBUG_SIG 0 | |
36 | ||
ac689eb7 | 37 | struct rt_sigframe { |
ac689eb7 JB |
38 | struct siginfo info; |
39 | struct ucontext uc; | |
40 | unsigned char retcode[16]; /* trampoline code */ | |
41 | }; | |
42 | ||
10f67dbf JB |
43 | static int restore_sigcontext(struct pt_regs *regs, |
44 | struct sigcontext __user *sc) | |
ac689eb7 | 45 | { |
10f67dbf | 46 | int err = 0; |
ac689eb7 | 47 | |
10f67dbf | 48 | /* Always make any pending restarted system calls return -EINTR */ |
f56141e3 | 49 | current->restart_block.fn = do_no_restart_syscall; |
ac689eb7 | 50 | |
d7cb6667 JB |
51 | /* |
52 | * Restore the regs from &sc->regs. | |
ac689eb7 JB |
53 | * (sc is already checked for VERIFY_READ since the sigframe was |
54 | * checked in sys_sigreturn previously) | |
55 | */ | |
10f67dbf JB |
56 | err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long)); |
57 | err |= __copy_from_user(®s->pc, &sc->regs.pc, sizeof(unsigned long)); | |
58 | err |= __copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long)); | |
ac689eb7 JB |
59 | |
60 | /* make sure the SM-bit is cleared so user-mode cannot fool us */ | |
61 | regs->sr &= ~SPR_SR_SM; | |
62 | ||
10f67dbf JB |
63 | regs->orig_gpr11 = -1; /* Avoid syscall restart checks */ |
64 | ||
ac689eb7 JB |
65 | /* TODO: the other ports use regs->orig_XX to disable syscall checks |
66 | * after this completes, but we don't use that mechanism. maybe we can | |
67 | * use it now ? | |
68 | */ | |
69 | ||
70 | return err; | |
ac689eb7 JB |
71 | } |
72 | ||
73 | asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs) | |
74 | { | |
75 | struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp; | |
76 | sigset_t set; | |
ac689eb7 JB |
77 | |
78 | /* | |
79 | * Since we stacked the signal on a dword boundary, | |
80 | * then frame should be dword aligned here. If it's | |
81 | * not, then the user is trying to mess with us. | |
82 | */ | |
83 | if (((long)frame) & 3) | |
84 | goto badframe; | |
85 | ||
86 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
87 | goto badframe; | |
88 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
89 | goto badframe; | |
90 | ||
d8d4b20d | 91 | set_current_blocked(&set); |
ac689eb7 JB |
92 | |
93 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
94 | goto badframe; | |
95 | ||
faec5a96 | 96 | if (restore_altstack(&frame->uc.uc_stack)) |
d26654e5 | 97 | goto badframe; |
ac689eb7 JB |
98 | |
99 | return regs->gpr[11]; | |
100 | ||
101 | badframe: | |
102 | force_sig(SIGSEGV, current); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * Set up a signal frame. | |
108 | */ | |
109 | ||
10f67dbf | 110 | static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) |
ac689eb7 JB |
111 | { |
112 | int err = 0; | |
ac689eb7 | 113 | |
d7cb6667 | 114 | /* copy the regs */ |
10f67dbf JB |
115 | /* There should be no need to save callee-saved registers here... |
116 | * ...but we save them anyway. Revisit this | |
117 | */ | |
d7cb6667 JB |
118 | err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long)); |
119 | err |= __copy_to_user(&sc->regs.pc, ®s->pc, sizeof(unsigned long)); | |
120 | err |= __copy_to_user(&sc->regs.sr, ®s->sr, sizeof(unsigned long)); | |
ac689eb7 | 121 | |
ac689eb7 JB |
122 | return err; |
123 | } | |
124 | ||
125 | static inline unsigned long align_sigframe(unsigned long sp) | |
126 | { | |
127 | return sp & ~3UL; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Work out where the signal frame should go. It's either on the user stack | |
132 | * or the alternate stack. | |
133 | */ | |
134 | ||
8e2beafa | 135 | static inline void __user *get_sigframe(struct ksignal *ksig, |
ac689eb7 JB |
136 | struct pt_regs *regs, size_t frame_size) |
137 | { | |
138 | unsigned long sp = regs->sp; | |
ac689eb7 JB |
139 | |
140 | /* redzone */ | |
141 | sp -= STACK_FRAME_OVERHEAD; | |
8e2beafa | 142 | sp = sigsp(sp, ksig); |
ac689eb7 JB |
143 | sp = align_sigframe(sp - frame_size); |
144 | ||
ac689eb7 JB |
145 | return (void __user *)sp; |
146 | } | |
147 | ||
148 | /* grab and setup a signal frame. | |
149 | * | |
150 | * basically we stack a lot of state info, and arrange for the | |
151 | * user-mode program to return to the kernel using either a | |
152 | * trampoline which performs the syscall sigreturn, or a provided | |
153 | * user-mode trampoline. | |
154 | */ | |
548dafe8 RW |
155 | static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, |
156 | struct pt_regs *regs) | |
ac689eb7 JB |
157 | { |
158 | struct rt_sigframe *frame; | |
159 | unsigned long return_ip; | |
160 | int err = 0; | |
161 | ||
8e2beafa | 162 | frame = get_sigframe(ksig, regs, sizeof(*frame)); |
548dafe8 | 163 | |
ac689eb7 | 164 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
548dafe8 | 165 | return -EFAULT; |
ac689eb7 | 166 | |
10f67dbf | 167 | /* Create siginfo. */ |
548dafe8 RW |
168 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
169 | err |= copy_siginfo_to_user(&frame->info, &ksig->info); | |
ac689eb7 | 170 | |
10f67dbf | 171 | /* Create the ucontext. */ |
ac689eb7 JB |
172 | err |= __put_user(0, &frame->uc.uc_flags); |
173 | err |= __put_user(NULL, &frame->uc.uc_link); | |
faec5a96 | 174 | err |= __save_altstack(&frame->uc.uc_stack, regs->sp); |
10f67dbf | 175 | err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); |
ac689eb7 JB |
176 | |
177 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
178 | ||
179 | if (err) | |
548dafe8 | 180 | return -EFAULT; |
ac689eb7 JB |
181 | |
182 | /* trampoline - the desired return ip is the retcode itself */ | |
183 | return_ip = (unsigned long)&frame->retcode; | |
10f67dbf JB |
184 | /* This is: |
185 | l.ori r11,r0,__NR_sigreturn | |
186 | l.sys 1 | |
187 | */ | |
188 | err |= __put_user(0xa960, (short *)(frame->retcode + 0)); | |
189 | err |= __put_user(__NR_rt_sigreturn, (short *)(frame->retcode + 2)); | |
ac689eb7 JB |
190 | err |= __put_user(0x20000001, (unsigned long *)(frame->retcode + 4)); |
191 | err |= __put_user(0x15000000, (unsigned long *)(frame->retcode + 8)); | |
192 | ||
193 | if (err) | |
548dafe8 | 194 | return -EFAULT; |
ac689eb7 | 195 | |
ac689eb7 | 196 | /* Set up registers for signal handler */ |
548dafe8 | 197 | regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */ |
ac689eb7 | 198 | regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */ |
548dafe8 | 199 | regs->gpr[3] = (unsigned long)ksig->sig; /* arg 1: signo */ |
ac689eb7 JB |
200 | regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */ |
201 | regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */ | |
202 | ||
203 | /* actually move the usp to reflect the stacked frame */ | |
204 | regs->sp = (unsigned long)frame; | |
205 | ||
e933c70d | 206 | return 0; |
ac689eb7 JB |
207 | } |
208 | ||
39974d08 | 209 | static inline void |
548dafe8 | 210 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
ac689eb7 | 211 | { |
e933c70d MF |
212 | int ret; |
213 | ||
548dafe8 | 214 | ret = setup_rt_frame(ksig, sigmask_to_save(), regs); |
ac689eb7 | 215 | |
548dafe8 | 216 | signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); |
ac689eb7 JB |
217 | } |
218 | ||
219 | /* | |
220 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
221 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
222 | * mistake. | |
223 | * | |
224 | * Also note that the regs structure given here as an argument, is the latest | |
225 | * pushed pt_regs. It may or may not be the same as the first pushed registers | |
226 | * when the initial usermode->kernelmode transition took place. Therefore | |
227 | * we can use user_mode(regs) to see if we came directly from kernel or user | |
228 | * mode below. | |
229 | */ | |
230 | ||
10f67dbf | 231 | int do_signal(struct pt_regs *regs, int syscall) |
ac689eb7 | 232 | { |
548dafe8 | 233 | struct ksignal ksig; |
10f67dbf JB |
234 | unsigned long continue_addr = 0; |
235 | unsigned long restart_addr = 0; | |
236 | unsigned long retval = 0; | |
237 | int restart = 0; | |
238 | ||
239 | if (syscall) { | |
240 | continue_addr = regs->pc; | |
241 | restart_addr = continue_addr - 4; | |
242 | retval = regs->gpr[11]; | |
243 | ||
244 | /* | |
245 | * Setup syscall restart here so that a debugger will | |
246 | * see the already changed PC. | |
247 | */ | |
248 | switch (retval) { | |
ac689eb7 | 249 | case -ERESTART_RESTARTBLOCK: |
10f67dbf JB |
250 | restart = -2; |
251 | /* Fall through */ | |
ac689eb7 | 252 | case -ERESTARTNOHAND: |
ac689eb7 | 253 | case -ERESTARTSYS: |
ac689eb7 | 254 | case -ERESTARTNOINTR: |
10f67dbf JB |
255 | restart++; |
256 | regs->gpr[11] = regs->orig_gpr11; | |
257 | regs->pc = restart_addr; | |
ac689eb7 JB |
258 | break; |
259 | } | |
10f67dbf | 260 | } |
ac689eb7 | 261 | |
10f67dbf | 262 | /* |
548dafe8 RW |
263 | * Get the signal to deliver. During the call to get_signal the |
264 | * debugger may change all our registers so we may need to revert | |
265 | * the decision to restart the syscall; specifically, if the PC is | |
266 | * changed, don't restart the syscall. | |
10f67dbf | 267 | */ |
548dafe8 | 268 | if (get_signal(&ksig)) { |
10f67dbf JB |
269 | if (unlikely(restart) && regs->pc == restart_addr) { |
270 | if (retval == -ERESTARTNOHAND || | |
271 | retval == -ERESTART_RESTARTBLOCK | |
272 | || (retval == -ERESTARTSYS | |
548dafe8 | 273 | && !(ksig.ka.sa.sa_flags & SA_RESTART))) { |
10f67dbf JB |
274 | /* No automatic restart */ |
275 | regs->gpr[11] = -EINTR; | |
276 | regs->pc = continue_addr; | |
277 | } | |
ac689eb7 | 278 | } |
548dafe8 | 279 | handle_signal(&ksig, regs); |
10f67dbf JB |
280 | } else { |
281 | /* no handler */ | |
282 | restore_saved_sigmask(); | |
283 | /* | |
284 | * Restore pt_regs PC as syscall restart will be handled by | |
285 | * kernel without return to userspace | |
286 | */ | |
287 | if (unlikely(restart) && regs->pc == restart_addr) { | |
288 | regs->pc = continue_addr; | |
289 | return restart; | |
290 | } | |
ac689eb7 JB |
291 | } |
292 | ||
10f67dbf | 293 | return 0; |
ac689eb7 JB |
294 | } |
295 | ||
10f67dbf JB |
296 | asmlinkage int |
297 | do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) | |
ac689eb7 | 298 | { |
10f67dbf JB |
299 | do { |
300 | if (likely(thread_flags & _TIF_NEED_RESCHED)) { | |
301 | schedule(); | |
302 | } else { | |
303 | if (unlikely(!user_mode(regs))) | |
304 | return 0; | |
305 | local_irq_enable(); | |
306 | if (thread_flags & _TIF_SIGPENDING) { | |
307 | int restart = do_signal(regs, syscall); | |
308 | if (unlikely(restart)) { | |
309 | /* | |
310 | * Restart without handlers. | |
311 | * Deal with it without leaving | |
312 | * the kernel space. | |
313 | */ | |
314 | return restart; | |
315 | } | |
316 | syscall = 0; | |
317 | } else { | |
318 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
319 | tracehook_notify_resume(regs); | |
320 | } | |
321 | } | |
322 | local_irq_disable(); | |
323 | thread_flags = current_thread_info()->flags; | |
324 | } while (thread_flags & _TIF_WORK_MASK); | |
325 | return 0; | |
ac689eb7 | 326 | } |