1 | /* |
2 | * Signal handling |
3 | * |
4 | * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> |
5 | * Copyright (C) 2008-2009 PetaLogix |
6 | * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au> |
7 | * Copyright (C) 2001 NEC Corporation |
8 | * Copyright (C) 2001 Miles Bader <miles@gnu.org> |
9 | * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima |
10 | * Copyright (C) 1991,1992 Linus Torvalds |
11 | * |
12 | * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson |
13 | * |
14 | * This file was derived from the sh version, arch/sh/kernel/signal.c |
15 | * |
16 | * This file is subject to the terms and conditions of the GNU General |
17 | * Public License. See the file COPYING in the main directory of this |
18 | * archive for more details. |
19 | */ |
20 | |
21 | #include <linux/sched.h> |
22 | #include <linux/mm.h> |
23 | #include <linux/smp.h> |
24 | #include <linux/kernel.h> |
25 | #include <linux/signal.h> |
26 | #include <linux/errno.h> |
27 | #include <linux/wait.h> |
28 | #include <linux/ptrace.h> |
29 | #include <linux/unistd.h> |
30 | #include <linux/stddef.h> |
31 | #include <linux/personality.h> |
32 | #include <linux/percpu.h> |
33 | #include <linux/linkage.h> |
34 | #include <linux/resume_user_mode.h> |
35 | #include <asm/entry.h> |
36 | #include <asm/ucontext.h> |
37 | #include <linux/uaccess.h> |
38 | #include <linux/syscalls.h> |
39 | #include <asm/cacheflush.h> |
40 | #include <asm/syscalls.h> |
41 | |
42 | /* |
43 | * Do a signal return; undo the signal stack. |
44 | */ |
45 | struct sigframe { |
46 | struct sigcontext sc; |
47 | unsigned long [_NSIG_WORDS-1]; |
48 | unsigned long tramp[2]; /* signal trampoline */ |
49 | }; |
50 | |
51 | struct rt_sigframe { |
52 | struct siginfo info; |
53 | struct ucontext uc; |
54 | unsigned long tramp[2]; /* signal trampoline */ |
55 | }; |
56 | |
57 | static int restore_sigcontext(struct pt_regs *regs, |
58 | struct sigcontext __user *sc, int *rval_p) |
59 | { |
60 | unsigned int err = 0; |
61 | |
62 | #define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); } |
63 | COPY(r0); |
64 | COPY(r1); |
65 | COPY(r2); COPY(r3); COPY(r4); COPY(r5); |
66 | COPY(r6); COPY(r7); COPY(r8); COPY(r9); |
67 | COPY(r10); COPY(r11); COPY(r12); COPY(r13); |
68 | COPY(r14); COPY(r15); COPY(r16); COPY(r17); |
69 | COPY(r18); COPY(r19); COPY(r20); COPY(r21); |
70 | COPY(r22); COPY(r23); COPY(r24); COPY(r25); |
71 | COPY(r26); COPY(r27); COPY(r28); COPY(r29); |
72 | COPY(r30); COPY(r31); |
73 | COPY(pc); COPY(ear); COPY(esr); COPY(fsr); |
74 | #undef COPY |
75 | |
76 | *rval_p = regs->r3; |
77 | |
78 | return err; |
79 | } |
80 | |
81 | asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) |
82 | { |
83 | struct rt_sigframe __user *frame = |
84 | (struct rt_sigframe __user *)(regs->r1); |
85 | |
86 | sigset_t set; |
87 | int rval; |
88 | |
89 | /* Always make any pending restarted system calls return -EINTR */ |
90 | current->restart_block.fn = do_no_restart_syscall; |
91 | |
92 | if (!access_ok(frame, sizeof(*frame))) |
93 | goto badframe; |
94 | |
95 | if (__copy_from_user(to: &set, from: &frame->uc.uc_sigmask, n: sizeof(set))) |
96 | goto badframe; |
97 | |
98 | set_current_blocked(&set); |
99 | |
100 | if (restore_sigcontext(regs, sc: &frame->uc.uc_mcontext, rval_p: &rval)) |
101 | goto badframe; |
102 | |
103 | if (restore_altstack(&frame->uc.uc_stack)) |
104 | goto badframe; |
105 | |
106 | return rval; |
107 | |
108 | badframe: |
109 | force_sig(SIGSEGV); |
110 | return 0; |
111 | } |
112 | |
113 | /* |
114 | * Set up a signal frame. |
115 | */ |
116 | |
117 | static int |
118 | setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, |
119 | unsigned long mask) |
120 | { |
121 | int err = 0; |
122 | |
123 | #define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); } |
124 | COPY(r0); |
125 | COPY(r1); |
126 | COPY(r2); COPY(r3); COPY(r4); COPY(r5); |
127 | COPY(r6); COPY(r7); COPY(r8); COPY(r9); |
128 | COPY(r10); COPY(r11); COPY(r12); COPY(r13); |
129 | COPY(r14); COPY(r15); COPY(r16); COPY(r17); |
130 | COPY(r18); COPY(r19); COPY(r20); COPY(r21); |
131 | COPY(r22); COPY(r23); COPY(r24); COPY(r25); |
132 | COPY(r26); COPY(r27); COPY(r28); COPY(r29); |
133 | COPY(r30); COPY(r31); |
134 | COPY(pc); COPY(ear); COPY(esr); COPY(fsr); |
135 | #undef COPY |
136 | |
137 | err |= __put_user(mask, &sc->oldmask); |
138 | |
139 | return err; |
140 | } |
141 | |
142 | /* |
143 | * Determine which stack to use.. |
144 | */ |
145 | static inline void __user * |
146 | get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size) |
147 | { |
148 | /* Default to using normal stack */ |
149 | unsigned long sp = sigsp(sp: regs->r1, ksig); |
150 | |
151 | return (void __user *)((sp - frame_size) & -8UL); |
152 | } |
153 | |
154 | static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, |
155 | struct pt_regs *regs) |
156 | { |
157 | struct rt_sigframe __user *frame; |
158 | int err = 0, sig = ksig->sig; |
159 | unsigned long address = 0; |
160 | pmd_t *pmdp; |
161 | pte_t *ptep; |
162 | |
163 | frame = get_sigframe(ksig, regs, frame_size: sizeof(*frame)); |
164 | |
165 | if (!access_ok(frame, sizeof(*frame))) |
166 | return -EFAULT; |
167 | |
168 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
169 | err |= copy_siginfo_to_user(to: &frame->info, from: &ksig->info); |
170 | |
171 | /* Create the ucontext. */ |
172 | err |= __put_user(0, &frame->uc.uc_flags); |
173 | err |= __put_user(NULL, &frame->uc.uc_link); |
174 | err |= __save_altstack(&frame->uc.uc_stack, regs->r1); |
175 | err |= setup_sigcontext(sc: &frame->uc.uc_mcontext, |
176 | regs, mask: set->sig[0]); |
177 | err |= __copy_to_user(to: &frame->uc.uc_sigmask, from: set, n: sizeof(*set)); |
178 | |
179 | /* Set up to return from userspace. If provided, use a stub |
180 | already in userspace. */ |
181 | /* minus 8 is offset to cater for "rtsd r15,8" */ |
182 | /* addi r12, r0, __NR_sigreturn */ |
183 | err |= __put_user(0x31800000 | __NR_rt_sigreturn , |
184 | frame->tramp + 0); |
185 | /* brki r14, 0x8 */ |
186 | err |= __put_user(0xb9cc0008, frame->tramp + 1); |
187 | |
188 | /* Return from sighandler will jump to the tramp. |
189 | Negative 8 offset because return is rtsd r15, 8 */ |
190 | regs->r15 = ((unsigned long)frame->tramp)-8; |
191 | |
192 | address = ((unsigned long)frame->tramp); |
193 | pmdp = pmd_off(current->mm, va: address); |
194 | |
195 | preempt_disable(); |
196 | ptep = pte_offset_map(pmd: pmdp, addr: address); |
197 | if (ptep && pte_present(a: *ptep)) { |
198 | address = (unsigned long) page_address(pte_page(*ptep)); |
199 | /* MS: I need add offset in page */ |
200 | address += ((unsigned long)frame->tramp) & ~PAGE_MASK; |
201 | /* MS address is virtual */ |
202 | address = __virt_to_phys(address); |
203 | invalidate_icache_range(address, address + 8); |
204 | flush_dcache_range(address, address + 8); |
205 | } |
206 | if (ptep) |
207 | pte_unmap(pte: ptep); |
208 | preempt_enable(); |
209 | if (err) |
210 | return -EFAULT; |
211 | |
212 | /* Set up registers for signal handler */ |
213 | regs->r1 = (unsigned long) frame; |
214 | |
215 | /* Signal handler args: */ |
216 | regs->r5 = sig; /* arg 0: signum */ |
217 | regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */ |
218 | regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */ |
219 | /* Offset to handle microblaze rtid r14, 0 */ |
220 | regs->pc = (unsigned long)ksig->ka.sa.sa_handler; |
221 | |
222 | #ifdef DEBUG_SIG |
223 | pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n" , |
224 | current->comm, current->pid, frame, regs->pc); |
225 | #endif |
226 | |
227 | return 0; |
228 | } |
229 | |
230 | /* Handle restarting system calls */ |
231 | static inline void |
232 | handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) |
233 | { |
234 | switch (regs->r3) { |
235 | case -ERESTART_RESTARTBLOCK: |
236 | case -ERESTARTNOHAND: |
237 | if (!has_handler) |
238 | goto do_restart; |
239 | regs->r3 = -EINTR; |
240 | break; |
241 | case -ERESTARTSYS: |
242 | if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { |
243 | regs->r3 = -EINTR; |
244 | break; |
245 | } |
246 | fallthrough; |
247 | case -ERESTARTNOINTR: |
248 | do_restart: |
249 | /* offset of 4 bytes to re-execute trap (brki) instruction */ |
250 | regs->pc -= 4; |
251 | break; |
252 | } |
253 | } |
254 | |
255 | /* |
256 | * OK, we're invoking a handler |
257 | */ |
258 | |
259 | static void |
260 | handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
261 | { |
262 | sigset_t *oldset = sigmask_to_save(); |
263 | int ret; |
264 | |
265 | /* Set up the stack frame */ |
266 | ret = setup_rt_frame(ksig, set: oldset, regs); |
267 | |
268 | signal_setup_done(failed: ret, ksig, test_thread_flag(TIF_SINGLESTEP)); |
269 | } |
270 | |
271 | /* |
272 | * Note that 'init' is a special process: it doesn't get signals it doesn't |
273 | * want to handle. Thus you cannot kill init even with a SIGKILL even by |
274 | * mistake. |
275 | * |
276 | * Note that we go through the signals twice: once to check the signals that |
277 | * the kernel can handle, and then we build all the user-level signal handling |
278 | * stack-frames in one go after that. |
279 | */ |
280 | static void do_signal(struct pt_regs *regs, int in_syscall) |
281 | { |
282 | struct ksignal ksig; |
283 | |
284 | #ifdef DEBUG_SIG |
285 | pr_info("do signal: %p %d\n" , regs, in_syscall); |
286 | pr_info("do signal2: %lx %lx %ld [%lx]\n" , regs->pc, regs->r1, |
287 | regs->r12, read_thread_flags()); |
288 | #endif |
289 | |
290 | if (get_signal(ksig: &ksig)) { |
291 | /* Whee! Actually deliver the signal. */ |
292 | if (in_syscall) |
293 | handle_restart(regs, ka: &ksig.ka, has_handler: 1); |
294 | handle_signal(ksig: &ksig, regs); |
295 | return; |
296 | } |
297 | |
298 | if (in_syscall) |
299 | handle_restart(regs, NULL, has_handler: 0); |
300 | |
301 | /* |
302 | * If there's no signal to deliver, we just put the saved sigmask |
303 | * back. |
304 | */ |
305 | restore_saved_sigmask(); |
306 | } |
307 | |
308 | asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall) |
309 | { |
310 | if (test_thread_flag(TIF_SIGPENDING) || |
311 | test_thread_flag(TIF_NOTIFY_SIGNAL)) |
312 | do_signal(regs, in_syscall); |
313 | |
314 | if (test_thread_flag(TIF_NOTIFY_RESUME)) |
315 | resume_user_mode_work(regs); |
316 | } |
317 | |