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arch/tile: Miscellaneous cleanup changes.
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1/*
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright 2010 Tilera Corporation. All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation, version 2.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
12 * NON INFRINGEMENT. See the GNU General Public License for
13 * more details.
14 */
15
16#include <linux/sched.h>
17#include <linux/mm.h>
18#include <linux/smp.h>
19#include <linux/smp_lock.h>
20#include <linux/kernel.h>
21#include <linux/signal.h>
22#include <linux/errno.h>
23#include <linux/wait.h>
24#include <linux/unistd.h>
25#include <linux/stddef.h>
26#include <linux/personality.h>
27#include <linux/suspend.h>
28#include <linux/ptrace.h>
29#include <linux/elf.h>
30#include <linux/compat.h>
31#include <linux/syscalls.h>
32#include <linux/uaccess.h>
33#include <asm/processor.h>
34#include <asm/ucontext.h>
35#include <asm/sigframe.h>
0707ad30 36#include <asm/syscalls.h>
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37#include <arch/interrupts.h>
38
39#define DEBUG_SIG 0
40
41#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
42
43
139ef32b 44long _sys_sigaltstack(const stack_t __user *uss,
0707ad30 45 stack_t __user *uoss, struct pt_regs *regs)
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46{
47 return do_sigaltstack(uss, uoss, regs->sp);
48}
49
50
51/*
52 * Do a signal return; undo the signal stack.
53 */
54
55int restore_sigcontext(struct pt_regs *regs,
56 struct sigcontext __user *sc, long *pr0)
57{
58 int err = 0;
59 int i;
60
61 /* Always make any pending restarted system calls return -EINTR */
62 current_thread_info()->restart_block.fn = do_no_restart_syscall;
63
64 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
65 err |= __get_user(((long *)regs)[i],
0707ad30 66 &((long __user *)(&sc->regs))[i]);
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67
68 regs->faultnum = INT_SWINT_1_SIGRETURN;
69
70 err |= __get_user(*pr0, &sc->regs.regs[0]);
71 return err;
72}
73
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74/* sigreturn() returns long since it restores r0 in the interrupted code. */
75long _sys_rt_sigreturn(struct pt_regs *regs)
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76{
77 struct rt_sigframe __user *frame =
78 (struct rt_sigframe __user *)(regs->sp);
79 sigset_t set;
80 long r0;
81
82 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
83 goto badframe;
84 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
85 goto badframe;
86
87 sigdelsetmask(&set, ~_BLOCKABLE);
88 spin_lock_irq(&current->sighand->siglock);
89 current->blocked = set;
90 recalc_sigpending();
91 spin_unlock_irq(&current->sighand->siglock);
92
93 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
94 goto badframe;
95
96 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
97 goto badframe;
98
99 return r0;
100
101badframe:
102 force_sig(SIGSEGV, current);
103 return 0;
104}
105
106/*
107 * Set up a signal frame.
108 */
109
110int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
111{
112 int i, err = 0;
113
114 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
115 err |= __put_user(((long *)regs)[i],
0707ad30 116 &((long __user *)(&sc->regs))[i]);
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117
118 return err;
119}
120
121/*
122 * Determine which stack to use..
123 */
124static inline void __user *get_sigframe(struct k_sigaction *ka,
125 struct pt_regs *regs,
126 size_t frame_size)
127{
128 unsigned long sp;
129
130 /* Default to using normal stack */
131 sp = regs->sp;
132
133 /*
134 * If we are on the alternate signal stack and would overflow
135 * it, don't. Return an always-bogus address instead so we
136 * will die with SIGSEGV.
137 */
138 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
0707ad30 139 return (void __user __force *)-1UL;
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140
141 /* This is the X/Open sanctioned signal stack switching. */
142 if (ka->sa.sa_flags & SA_ONSTACK) {
143 if (sas_ss_flags(sp) == 0)
144 sp = current->sas_ss_sp + current->sas_ss_size;
145 }
146
147 sp -= frame_size;
148 /*
149 * Align the stack pointer according to the TILE ABI,
150 * i.e. so that on function entry (sp & 15) == 0.
151 */
152 sp &= -16UL;
153 return (void __user *) sp;
154}
155
156static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
157 sigset_t *set, struct pt_regs *regs)
158{
159 unsigned long restorer;
160 struct rt_sigframe __user *frame;
161 int err = 0;
162 int usig;
163
164 frame = get_sigframe(ka, regs, sizeof(*frame));
165
166 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
167 goto give_sigsegv;
168
169 usig = current_thread_info()->exec_domain
170 && current_thread_info()->exec_domain->signal_invmap
171 && sig < 32
172 ? current_thread_info()->exec_domain->signal_invmap[sig]
173 : sig;
174
175 /* Always write at least the signal number for the stack backtracer. */
176 if (ka->sa.sa_flags & SA_SIGINFO) {
177 /* At sigreturn time, restore the callee-save registers too. */
178 err |= copy_siginfo_to_user(&frame->info, info);
179 regs->flags |= PT_FLAGS_RESTORE_REGS;
180 } else {
181 err |= __put_user(info->si_signo, &frame->info.si_signo);
182 }
183
184 /* Create the ucontext. */
185 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
186 err |= __put_user(0, &frame->uc.uc_flags);
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187 err |= __put_user(NULL, &frame->uc.uc_link);
188 err |= __put_user((void __user *)(current->sas_ss_sp),
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189 &frame->uc.uc_stack.ss_sp);
190 err |= __put_user(sas_ss_flags(regs->sp),
191 &frame->uc.uc_stack.ss_flags);
192 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
193 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
194 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
195 if (err)
196 goto give_sigsegv;
197
198 restorer = VDSO_BASE;
199 if (ka->sa.sa_flags & SA_RESTORER)
200 restorer = (unsigned long) ka->sa.sa_restorer;
201
202 /*
203 * Set up registers for signal handler.
204 * Registers that we don't modify keep the value they had from
205 * user-space at the time we took the signal.
206 */
207 regs->pc = (unsigned long) ka->sa.sa_handler;
208 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
209 regs->sp = (unsigned long) frame;
210 regs->lr = restorer;
211 regs->regs[0] = (unsigned long) usig;
212
213 if (ka->sa.sa_flags & SA_SIGINFO) {
214 /* Need extra arguments, so mark to restore caller-saves. */
215 regs->regs[1] = (unsigned long) &frame->info;
216 regs->regs[2] = (unsigned long) &frame->uc;
217 regs->flags |= PT_FLAGS_CALLER_SAVES;
218 }
219
220 /*
221 * Notify any tracer that was single-stepping it.
222 * The tracer may want to single-step inside the
223 * handler too.
224 */
225 if (test_thread_flag(TIF_SINGLESTEP))
226 ptrace_notify(SIGTRAP);
227
228 return 0;
229
230give_sigsegv:
231 force_sigsegv(sig, current);
232 return -EFAULT;
233}
234
235/*
236 * OK, we're invoking a handler
237 */
238
239static int handle_signal(unsigned long sig, siginfo_t *info,
240 struct k_sigaction *ka, sigset_t *oldset,
241 struct pt_regs *regs)
242{
243 int ret;
244
245
246 /* Are we from a system call? */
247 if (regs->faultnum == INT_SWINT_1) {
248 /* If so, check system call restarting.. */
249 switch (regs->regs[0]) {
250 case -ERESTART_RESTARTBLOCK:
251 case -ERESTARTNOHAND:
252 regs->regs[0] = -EINTR;
253 break;
254
255 case -ERESTARTSYS:
256 if (!(ka->sa.sa_flags & SA_RESTART)) {
257 regs->regs[0] = -EINTR;
258 break;
259 }
260 /* fallthrough */
261 case -ERESTARTNOINTR:
262 /* Reload caller-saves to restore r0..r5 and r10. */
263 regs->flags |= PT_FLAGS_CALLER_SAVES;
264 regs->regs[0] = regs->orig_r0;
265 regs->pc -= 8;
266 }
267 }
268
269 /* Set up the stack frame */
270#ifdef CONFIG_COMPAT
271 if (is_compat_task())
272 ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
273 else
274#endif
275 ret = setup_rt_frame(sig, ka, info, oldset, regs);
276 if (ret == 0) {
277 /* This code is only called from system calls or from
278 * the work_pending path in the return-to-user code, and
279 * either way we can re-enable interrupts unconditionally.
280 */
281 spin_lock_irq(&current->sighand->siglock);
282 sigorsets(&current->blocked,
283 &current->blocked, &ka->sa.sa_mask);
284 if (!(ka->sa.sa_flags & SA_NODEFER))
285 sigaddset(&current->blocked, sig);
286 recalc_sigpending();
287 spin_unlock_irq(&current->sighand->siglock);
288 }
289
290 return ret;
291}
292
293/*
294 * Note that 'init' is a special process: it doesn't get signals it doesn't
295 * want to handle. Thus you cannot kill init even with a SIGKILL even by
296 * mistake.
297 */
298void do_signal(struct pt_regs *regs)
299{
300 siginfo_t info;
301 int signr;
302 struct k_sigaction ka;
303 sigset_t *oldset;
304
305 /*
306 * i386 will check if we're coming from kernel mode and bail out
307 * here. In my experience this just turns weird crashes into
308 * weird spin-hangs. But if we find a case where this seems
309 * helpful, we can reinstate the check on "!user_mode(regs)".
310 */
311
312 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
313 oldset = &current->saved_sigmask;
314 else
315 oldset = &current->blocked;
316
317 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
318 if (signr > 0) {
319 /* Whee! Actually deliver the signal. */
320 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
321 /*
322 * A signal was successfully delivered; the saved
323 * sigmask will have been stored in the signal frame,
324 * and will be restored by sigreturn, so we can simply
325 * clear the TS_RESTORE_SIGMASK flag.
326 */
327 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
328 }
329
330 return;
331 }
332
333 /* Did we come from a system call? */
334 if (regs->faultnum == INT_SWINT_1) {
335 /* Restart the system call - no handlers present */
336 switch (regs->regs[0]) {
337 case -ERESTARTNOHAND:
338 case -ERESTARTSYS:
339 case -ERESTARTNOINTR:
340 regs->flags |= PT_FLAGS_CALLER_SAVES;
341 regs->regs[0] = regs->orig_r0;
342 regs->pc -= 8;
343 break;
344
345 case -ERESTART_RESTARTBLOCK:
346 regs->flags |= PT_FLAGS_CALLER_SAVES;
347 regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
348 regs->pc -= 8;
349 break;
350 }
351 }
352
353 /* If there's no signal to deliver, just put the saved sigmask back. */
354 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
355 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
356 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
357 }
358}