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/kernel.h>
20 #include <linux/signal.h>
21 #include <linux/errno.h>
22 #include <linux/wait.h>
23 #include <linux/unistd.h>
24 #include <linux/stddef.h>
25 #include <linux/personality.h>
26 #include <linux/suspend.h>
27 #include <linux/ptrace.h>
28 #include <linux/elf.h>
29 #include <linux/compat.h>
30 #include <linux/syscalls.h>
31 #include <linux/uaccess.h>
32 #include <asm/processor.h>
33 #include <asm/ucontext.h>
34 #include <asm/sigframe.h>
35 #include <asm/syscalls.h>
37 #include <arch/interrupts.h>
42 * Do a signal return; undo the signal stack.
45 int restore_sigcontext(struct pt_regs *regs,
46 struct sigcontext __user *sc)
50 /* Always make any pending restarted system calls return -EINTR */
51 current->restart_block.fn = do_no_restart_syscall;
54 * Enforce that sigcontext is like pt_regs, and doesn't mess
55 * up our stack alignment rules.
57 BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
58 BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
59 err = __copy_from_user(regs, sc, sizeof(*regs));
61 /* Ensure that the PL is always set to USER_PL. */
62 regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
64 regs->faultnum = INT_SWINT_1_SIGRETURN;
69 void signal_fault(const char *type, struct pt_regs *regs,
70 void __user *frame, int sig)
72 trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
73 force_sigsegv(sig, current);
76 /* The assembly shim for this function arranges to ignore the return value. */
77 SYSCALL_DEFINE0(rt_sigreturn)
79 struct pt_regs *regs = current_pt_regs();
80 struct rt_sigframe __user *frame =
81 (struct rt_sigframe __user *)(regs->sp);
84 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
86 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
89 set_current_blocked(&set);
91 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
94 if (restore_altstack(&frame->uc.uc_stack))
100 signal_fault("bad sigreturn frame", regs, frame, 0);
105 * Set up a signal frame.
108 int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
110 return __copy_to_user(sc, regs, sizeof(*regs));
114 * Determine which stack to use..
116 static inline void __user *get_sigframe(struct k_sigaction *ka,
117 struct pt_regs *regs,
122 /* Default to using normal stack */
126 * If we are on the alternate signal stack and would overflow
127 * it, don't. Return an always-bogus address instead so we
128 * will die with SIGSEGV.
130 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
131 return (void __user __force *)-1UL;
133 /* This is the X/Open sanctioned signal stack switching. */
134 if (ka->sa.sa_flags & SA_ONSTACK) {
135 if (sas_ss_flags(sp) == 0)
136 sp = current->sas_ss_sp + current->sas_ss_size;
141 * Align the stack pointer according to the TILE ABI,
142 * i.e. so that on function entry (sp & 15) == 0.
145 return (void __user *) sp;
148 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
149 struct pt_regs *regs)
151 unsigned long restorer;
152 struct rt_sigframe __user *frame;
153 int err = 0, sig = ksig->sig;
156 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
158 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
161 usig = current_thread_info()->exec_domain
162 && current_thread_info()->exec_domain->signal_invmap
164 ? current_thread_info()->exec_domain->signal_invmap[sig]
167 /* Always write at least the signal number for the stack backtracer. */
168 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
169 /* At sigreturn time, restore the callee-save registers too. */
170 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
171 regs->flags |= PT_FLAGS_RESTORE_REGS;
173 err |= __put_user(ksig->info.si_signo, &frame->info.si_signo);
176 /* Create the ucontext. */
177 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
178 err |= __put_user(0, &frame->uc.uc_flags);
179 err |= __put_user(NULL, &frame->uc.uc_link);
180 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
181 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
182 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
186 restorer = VDSO_SYM(&__vdso_rt_sigreturn);
187 if (ksig->ka.sa.sa_flags & SA_RESTORER)
188 restorer = (unsigned long) ksig->ka.sa.sa_restorer;
191 * Set up registers for signal handler.
192 * Registers that we don't modify keep the value they had from
193 * user-space at the time we took the signal.
194 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
195 * since some things rely on this (e.g. glibc's debug/segfault.c).
197 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
198 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
199 regs->sp = (unsigned long) frame;
201 regs->regs[0] = (unsigned long) usig;
202 regs->regs[1] = (unsigned long) &frame->info;
203 regs->regs[2] = (unsigned long) &frame->uc;
204 regs->flags |= PT_FLAGS_CALLER_SAVES;
208 trace_unhandled_signal("bad sigreturn frame", regs,
209 (unsigned long)frame, SIGSEGV);
214 * OK, we're invoking a handler
217 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
219 sigset_t *oldset = sigmask_to_save();
222 /* Are we from a system call? */
223 if (regs->faultnum == INT_SWINT_1) {
224 /* If so, check system call restarting.. */
225 switch (regs->regs[0]) {
226 case -ERESTART_RESTARTBLOCK:
227 case -ERESTARTNOHAND:
228 regs->regs[0] = -EINTR;
232 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
233 regs->regs[0] = -EINTR;
237 case -ERESTARTNOINTR:
238 /* Reload caller-saves to restore r0..r5 and r10. */
239 regs->flags |= PT_FLAGS_CALLER_SAVES;
240 regs->regs[0] = regs->orig_r0;
245 /* Set up the stack frame */
247 if (is_compat_task())
248 ret = compat_setup_rt_frame(ksig, oldset, regs);
251 ret = setup_rt_frame(ksig, oldset, regs);
253 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
257 * Note that 'init' is a special process: it doesn't get signals it doesn't
258 * want to handle. Thus you cannot kill init even with a SIGKILL even by
261 void do_signal(struct pt_regs *regs)
266 * i386 will check if we're coming from kernel mode and bail out
267 * here. In my experience this just turns weird crashes into
268 * weird spin-hangs. But if we find a case where this seems
269 * helpful, we can reinstate the check on "!user_mode(regs)".
272 if (get_signal(&ksig)) {
273 /* Whee! Actually deliver the signal. */
274 handle_signal(&ksig, regs);
278 /* Did we come from a system call? */
279 if (regs->faultnum == INT_SWINT_1) {
280 /* Restart the system call - no handlers present */
281 switch (regs->regs[0]) {
282 case -ERESTARTNOHAND:
284 case -ERESTARTNOINTR:
285 regs->flags |= PT_FLAGS_CALLER_SAVES;
286 regs->regs[0] = regs->orig_r0;
290 case -ERESTART_RESTARTBLOCK:
291 regs->flags |= PT_FLAGS_CALLER_SAVES;
292 regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
298 /* If there's no signal to deliver, just put the saved sigmask back. */
299 restore_saved_sigmask();
302 /* Avoid double syscall restart if there are nested signals. */
303 regs->faultnum = INT_SWINT_1_SIGRETURN;
306 int show_unhandled_signals = 1;
308 static int __init crashinfo(char *str)
313 show_unhandled_signals = 2;
314 else if (*str != '=' || kstrtoint(++str, 0, &show_unhandled_signals) != 0)
317 switch (show_unhandled_signals) {
328 pr_info("%s crash reports will be generated on the console\n", word);
331 __setup("crashinfo", crashinfo);
333 static void dump_mem(void __user *address)
336 enum { region_size = 256, bytes_per_line = 16 };
338 int found_readable_mem = 0;
340 if (!access_ok(VERIFY_READ, address, 1)) {
341 pr_err("Not dumping at address 0x%lx (kernel address)\n",
342 (unsigned long)address);
346 addr = (void __user *)
347 (((unsigned long)address & -bytes_per_line) - region_size/2);
350 for (i = 0; i < region_size;
351 addr += bytes_per_line, i += bytes_per_line) {
352 unsigned char buf[bytes_per_line];
354 if (copy_from_user(buf, addr, bytes_per_line))
356 if (!found_readable_mem) {
357 pr_err("Dumping memory around address 0x%lx:\n",
358 (unsigned long)address);
359 found_readable_mem = 1;
361 j = sprintf(line, REGFMT ":", (unsigned long)addr);
362 for (k = 0; k < bytes_per_line; ++k)
363 j += sprintf(&line[j], " %02x", buf[k]);
364 pr_err("%s\n", line);
366 if (!found_readable_mem)
367 pr_err("No readable memory around address 0x%lx\n",
368 (unsigned long)address);
371 void trace_unhandled_signal(const char *type, struct pt_regs *regs,
372 unsigned long address, int sig)
374 struct task_struct *tsk = current;
376 if (show_unhandled_signals == 0)
379 /* If the signal is handled, don't show it here. */
380 if (!is_global_init(tsk)) {
381 void __user *handler =
382 tsk->sighand->action[sig-1].sa.sa_handler;
383 if (handler != SIG_IGN && handler != SIG_DFL)
387 /* Rate-limit the one-line output, not the detailed output. */
388 if (show_unhandled_signals <= 1 && !printk_ratelimit())
391 printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
392 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
393 tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
395 print_vma_addr(KERN_CONT " in ", regs->pc);
397 printk(KERN_CONT "\n");
399 if (show_unhandled_signals > 1) {
405 pr_err("User crash: signal %d, trap %ld, address 0x%lx\n",
406 sig, regs->faultnum, address);
408 dump_mem((void __user *)address);
411 pr_err("User crash: signal %d, trap %ld\n",
412 sig, regs->faultnum);