2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright 2010 Tilera Corporation. All Rights Reserved.
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.
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
16 #include <linux/sched.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>
36 #include <asm/syscalls.h>
37 #include <arch/interrupts.h>
41 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
44 SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss,
45 stack_t __user *, uoss, struct pt_regs *, regs)
47 return do_sigaltstack(uss, uoss, regs->sp);
52 * Do a signal return; undo the signal stack.
55 int restore_sigcontext(struct pt_regs *regs,
56 struct sigcontext __user *sc, long *pr0)
61 /* Always make any pending restarted system calls return -EINTR */
62 current_thread_info()->restart_block.fn = do_no_restart_syscall;
65 * Enforce that sigcontext is like pt_regs, and doesn't mess
66 * up our stack alignment rules.
68 BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
69 BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
71 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
72 err |= __get_user(regs->regs[i], &sc->gregs[i]);
74 /* Ensure that the PL is always set to USER_PL. */
75 regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
77 regs->faultnum = INT_SWINT_1_SIGRETURN;
79 err |= __get_user(*pr0, &sc->gregs[0]);
83 /* sigreturn() returns long since it restores r0 in the interrupted code. */
84 SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs)
86 struct rt_sigframe __user *frame =
87 (struct rt_sigframe __user *)(regs->sp);
91 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
93 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
96 sigdelsetmask(&set, ~_BLOCKABLE);
97 spin_lock_irq(¤t->sighand->siglock);
98 current->blocked = set;
100 spin_unlock_irq(¤t->sighand->siglock);
102 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
105 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
111 force_sig(SIGSEGV, current);
116 * Set up a signal frame.
119 int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
123 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
124 err |= __put_user(regs->regs[i], &sc->gregs[i]);
130 * Determine which stack to use..
132 static inline void __user *get_sigframe(struct k_sigaction *ka,
133 struct pt_regs *regs,
138 /* Default to using normal stack */
142 * If we are on the alternate signal stack and would overflow
143 * it, don't. Return an always-bogus address instead so we
144 * will die with SIGSEGV.
146 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
147 return (void __user __force *)-1UL;
149 /* This is the X/Open sanctioned signal stack switching. */
150 if (ka->sa.sa_flags & SA_ONSTACK) {
151 if (sas_ss_flags(sp) == 0)
152 sp = current->sas_ss_sp + current->sas_ss_size;
157 * Align the stack pointer according to the TILE ABI,
158 * i.e. so that on function entry (sp & 15) == 0.
161 return (void __user *) sp;
164 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
165 sigset_t *set, struct pt_regs *regs)
167 unsigned long restorer;
168 struct rt_sigframe __user *frame;
172 frame = get_sigframe(ka, regs, sizeof(*frame));
174 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
177 usig = current_thread_info()->exec_domain
178 && current_thread_info()->exec_domain->signal_invmap
180 ? current_thread_info()->exec_domain->signal_invmap[sig]
183 /* Always write at least the signal number for the stack backtracer. */
184 if (ka->sa.sa_flags & SA_SIGINFO) {
185 /* At sigreturn time, restore the callee-save registers too. */
186 err |= copy_siginfo_to_user(&frame->info, info);
187 regs->flags |= PT_FLAGS_RESTORE_REGS;
189 err |= __put_user(info->si_signo, &frame->info.si_signo);
192 /* Create the ucontext. */
193 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
194 err |= __put_user(0, &frame->uc.uc_flags);
195 err |= __put_user(NULL, &frame->uc.uc_link);
196 err |= __put_user((void __user *)(current->sas_ss_sp),
197 &frame->uc.uc_stack.ss_sp);
198 err |= __put_user(sas_ss_flags(regs->sp),
199 &frame->uc.uc_stack.ss_flags);
200 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
201 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
202 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
206 restorer = VDSO_BASE;
207 if (ka->sa.sa_flags & SA_RESTORER)
208 restorer = (unsigned long) ka->sa.sa_restorer;
211 * Set up registers for signal handler.
212 * Registers that we don't modify keep the value they had from
213 * user-space at the time we took the signal.
214 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
215 * since some things rely on this (e.g. glibc's debug/segfault.c).
217 regs->pc = (unsigned long) ka->sa.sa_handler;
218 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
219 regs->sp = (unsigned long) frame;
221 regs->regs[0] = (unsigned long) usig;
222 regs->regs[1] = (unsigned long) &frame->info;
223 regs->regs[2] = (unsigned long) &frame->uc;
224 regs->flags |= PT_FLAGS_CALLER_SAVES;
227 * Notify any tracer that was single-stepping it.
228 * The tracer may want to single-step inside the
231 if (test_thread_flag(TIF_SINGLESTEP))
232 ptrace_notify(SIGTRAP);
237 force_sigsegv(sig, current);
242 * OK, we're invoking a handler
245 static int handle_signal(unsigned long sig, siginfo_t *info,
246 struct k_sigaction *ka, sigset_t *oldset,
247 struct pt_regs *regs)
252 /* Are we from a system call? */
253 if (regs->faultnum == INT_SWINT_1) {
254 /* If so, check system call restarting.. */
255 switch (regs->regs[0]) {
256 case -ERESTART_RESTARTBLOCK:
257 case -ERESTARTNOHAND:
258 regs->regs[0] = -EINTR;
262 if (!(ka->sa.sa_flags & SA_RESTART)) {
263 regs->regs[0] = -EINTR;
267 case -ERESTARTNOINTR:
268 /* Reload caller-saves to restore r0..r5 and r10. */
269 regs->flags |= PT_FLAGS_CALLER_SAVES;
270 regs->regs[0] = regs->orig_r0;
275 /* Set up the stack frame */
277 if (is_compat_task())
278 ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
281 ret = setup_rt_frame(sig, ka, info, oldset, regs);
283 /* This code is only called from system calls or from
284 * the work_pending path in the return-to-user code, and
285 * either way we can re-enable interrupts unconditionally.
287 spin_lock_irq(¤t->sighand->siglock);
288 sigorsets(¤t->blocked,
289 ¤t->blocked, &ka->sa.sa_mask);
290 if (!(ka->sa.sa_flags & SA_NODEFER))
291 sigaddset(¤t->blocked, sig);
293 spin_unlock_irq(¤t->sighand->siglock);
300 * Note that 'init' is a special process: it doesn't get signals it doesn't
301 * want to handle. Thus you cannot kill init even with a SIGKILL even by
304 void do_signal(struct pt_regs *regs)
308 struct k_sigaction ka;
312 * i386 will check if we're coming from kernel mode and bail out
313 * here. In my experience this just turns weird crashes into
314 * weird spin-hangs. But if we find a case where this seems
315 * helpful, we can reinstate the check on "!user_mode(regs)".
318 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
319 oldset = ¤t->saved_sigmask;
321 oldset = ¤t->blocked;
323 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
325 /* Whee! Actually deliver the signal. */
326 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
328 * A signal was successfully delivered; the saved
329 * sigmask will have been stored in the signal frame,
330 * and will be restored by sigreturn, so we can simply
331 * clear the TS_RESTORE_SIGMASK flag.
333 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
339 /* Did we come from a system call? */
340 if (regs->faultnum == INT_SWINT_1) {
341 /* Restart the system call - no handlers present */
342 switch (regs->regs[0]) {
343 case -ERESTARTNOHAND:
345 case -ERESTARTNOINTR:
346 regs->flags |= PT_FLAGS_CALLER_SAVES;
347 regs->regs[0] = regs->orig_r0;
351 case -ERESTART_RESTARTBLOCK:
352 regs->flags |= PT_FLAGS_CALLER_SAVES;
353 regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
359 /* If there's no signal to deliver, just put the saved sigmask back. */
360 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
361 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
362 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
366 /* Avoid double syscall restart if there are nested signals. */
367 regs->faultnum = INT_SWINT_1_SIGRETURN;