4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
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>
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.
18 #include <linux/sched.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>
30 #include <asm/processor.h>
31 #include <asm/ucontext.h>
32 #include <asm/uaccess.h>
36 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
39 _sys_sigaltstack(const stack_t *uss, stack_t *uoss, struct pt_regs *regs)
41 return do_sigaltstack(uss, uoss, regs->sp);
45 struct siginfo *pinfo;
49 unsigned char retcode[16]; /* trampoline code */
52 static int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
55 unsigned long old_usp;
57 /* Alwys make any pending restarted system call return -EINTR */
58 current_thread_info()->restart_block.fn = do_no_restart_syscall;
60 /* restore the regs from &sc->regs (same as sc, since regs is first)
61 * (sc is already checked for VERIFY_READ since the sigframe was
62 * checked in sys_sigreturn previously)
65 if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
68 /* make sure the SM-bit is cleared so user-mode cannot fool us */
69 regs->sr &= ~SPR_SR_SM;
71 /* restore the old USP as it was before we stacked the sc etc.
72 * (we cannot just pop the sigcontext since we aligned the sp and
73 * stuff after pushing it)
76 err |= __get_user(old_usp, &sc->usp);
80 /* TODO: the other ports use regs->orig_XX to disable syscall checks
81 * after this completes, but we don't use that mechanism. maybe we can
91 asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
93 struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp;
98 * Since we stacked the signal on a dword boundary,
99 * then frame should be dword aligned here. If it's
100 * not, then the user is trying to mess with us.
102 if (((long)frame) & 3)
105 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
107 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
110 sigdelsetmask(&set, ~_BLOCKABLE);
111 spin_lock_irq(¤t->sighand->siglock);
112 current->blocked = set;
114 spin_unlock_irq(¤t->sighand->siglock);
116 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
119 if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
121 /* It is more difficult to avoid calling this function than to
122 call it and ignore errors. */
123 do_sigaltstack(&st, NULL, regs->sp);
125 return regs->gpr[11];
128 force_sig(SIGSEGV, current);
133 * Set up a signal frame.
136 static int setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
140 unsigned long usp = regs->sp;
142 /* copy the regs. they are first in sc so we can use sc directly */
144 err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
146 /* then some other stuff */
148 err |= __put_user(mask, &sc->oldmask);
150 err |= __put_user(usp, &sc->usp);
155 static inline unsigned long align_sigframe(unsigned long sp)
161 * Work out where the signal frame should go. It's either on the user stack
162 * or the alternate stack.
165 static inline void __user *get_sigframe(struct k_sigaction *ka,
166 struct pt_regs *regs, size_t frame_size)
168 unsigned long sp = regs->sp;
169 int onsigstack = on_sig_stack(sp);
172 sp -= STACK_FRAME_OVERHEAD;
174 /* This is the X/Open sanctioned signal stack switching. */
175 if ((ka->sa.sa_flags & SA_ONSTACK) && !onsigstack) {
176 if (current->sas_ss_size)
177 sp = current->sas_ss_sp + current->sas_ss_size;
180 sp = align_sigframe(sp - frame_size);
183 * If we are on the alternate signal stack and would overflow it, don't.
184 * Return an always-bogus address instead so we will die with SIGSEGV.
186 if (onsigstack && !likely(on_sig_stack(sp)))
187 return (void __user *)-1L;
189 return (void __user *)sp;
192 /* grab and setup a signal frame.
194 * basically we stack a lot of state info, and arrange for the
195 * user-mode program to return to the kernel using either a
196 * trampoline which performs the syscall sigreturn, or a provided
197 * user-mode trampoline.
199 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
200 sigset_t *set, struct pt_regs *regs)
202 struct rt_sigframe *frame;
203 unsigned long return_ip;
206 frame = get_sigframe(ka, regs, sizeof(*frame));
208 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
211 err |= __put_user(&frame->info, &frame->pinfo);
212 err |= __put_user(&frame->uc, &frame->puc);
214 if (ka->sa.sa_flags & SA_SIGINFO)
215 err |= copy_siginfo_to_user(&frame->info, info);
219 /* Clear all the bits of the ucontext we don't use. */
220 err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
221 err |= __put_user(0, &frame->uc.uc_flags);
222 err |= __put_user(NULL, &frame->uc.uc_link);
223 err |= __put_user((void *)current->sas_ss_sp,
224 &frame->uc.uc_stack.ss_sp);
225 err |= __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags);
226 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
227 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
229 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
234 /* trampoline - the desired return ip is the retcode itself */
235 return_ip = (unsigned long)&frame->retcode;
236 /* This is l.ori r11,r0,__NR_sigreturn, l.sys 1 */
237 err |= __put_user(0xa960, (short *)(frame->retcode + 0));
238 err |= __put_user(__NR_rt_sigreturn, (short *)(frame->retcode + 2));
239 err |= __put_user(0x20000001, (unsigned long *)(frame->retcode + 4));
240 err |= __put_user(0x15000000, (unsigned long *)(frame->retcode + 8));
245 /* TODO what is the current->exec_domain stuff and invmap ? */
247 /* Set up registers for signal handler */
248 regs->pc = (unsigned long)ka->sa.sa_handler; /* what we enter NOW */
249 regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */
250 regs->gpr[3] = (unsigned long)sig; /* arg 1: signo */
251 regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */
252 regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */
254 /* actually move the usp to reflect the stacked frame */
255 regs->sp = (unsigned long)frame;
261 ka->sa.sa_handler = SIG_DFL;
262 force_sig(SIGSEGV, current);
266 handle_signal(unsigned long sig,
267 siginfo_t *info, struct k_sigaction *ka,
268 sigset_t *oldset, struct pt_regs *regs)
270 setup_rt_frame(sig, ka, info, oldset, regs);
272 if (ka->sa.sa_flags & SA_ONESHOT)
273 ka->sa.sa_handler = SIG_DFL;
275 spin_lock_irq(¤t->sighand->siglock);
276 sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
277 if (!(ka->sa.sa_flags & SA_NODEFER))
278 sigaddset(¤t->blocked, sig);
281 spin_unlock_irq(¤t->sighand->siglock);
285 * Note that 'init' is a special process: it doesn't get signals it doesn't
286 * want to handle. Thus you cannot kill init even with a SIGKILL even by
289 * Also note that the regs structure given here as an argument, is the latest
290 * pushed pt_regs. It may or may not be the same as the first pushed registers
291 * when the initial usermode->kernelmode transition took place. Therefore
292 * we can use user_mode(regs) to see if we came directly from kernel or user
296 void do_signal(struct pt_regs *regs)
300 struct k_sigaction ka;
303 * We want the common case to go fast, which
304 * is why we may in certain cases get here from
305 * kernel mode. Just return without doing anything
308 if (!user_mode(regs))
311 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
313 /* If we are coming out of a syscall then we need
314 * to check if the syscall was interrupted and wants to be
315 * restarted after handling the signal. If so, the original
316 * syscall number is put back into r11 and the PC rewound to
317 * point at the l.sys instruction that resulted in the
318 * original syscall. Syscall results other than the four
319 * below mean that the syscall executed to completion and no
320 * restart is necessary.
322 if (regs->syscallno) {
325 switch (regs->gpr[11]) {
326 case -ERESTART_RESTARTBLOCK:
327 case -ERESTARTNOHAND:
328 /* Restart if there is no signal handler */
329 restart = (signr <= 0);
332 /* Restart if there no signal handler or
333 * SA_RESTART flag is set */
334 restart = (signr <= 0 || (ka.sa.sa_flags & SA_RESTART));
336 case -ERESTARTNOINTR:
343 if (regs->gpr[11] == -ERESTART_RESTARTBLOCK)
344 regs->gpr[11] = __NR_restart_syscall;
346 regs->gpr[11] = regs->orig_gpr11;
349 regs->gpr[11] = -EINTR;
354 /* no signal to deliver so we just put the saved sigmask
356 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
357 clear_thread_flag(TIF_RESTORE_SIGMASK);
358 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
361 } else { /* signr > 0 */
364 if (current_thread_info()->flags & _TIF_RESTORE_SIGMASK)
365 oldset = ¤t->saved_sigmask;
367 oldset = ¤t->blocked;
369 /* Whee! Actually deliver the signal. */
370 handle_signal(signr, &info, &ka, oldset, regs);
371 /* a signal was successfully delivered; the saved
372 * sigmask will have been stored in the signal frame,
373 * and will be restored by sigreturn, so we can simply
374 * clear the TIF_RESTORE_SIGMASK flag */
375 if (test_thread_flag(TIF_RESTORE_SIGMASK))
376 clear_thread_flag(TIF_RESTORE_SIGMASK);
378 tracehook_signal_handler(signr, &info, &ka, regs,
379 test_thread_flag(TIF_SINGLESTEP));
385 asmlinkage void do_notify_resume(struct pt_regs *regs)
387 if (current_thread_info()->flags & _TIF_SIGPENDING)
390 if (current_thread_info()->flags & _TIF_NOTIFY_RESUME) {
391 clear_thread_flag(TIF_NOTIFY_RESUME);
392 tracehook_notify_resume(regs);
393 if (current->replacement_session_keyring)
394 key_replace_session_keyring();