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>
37 _sys_sigaltstack(const stack_t *uss, stack_t *uoss, struct pt_regs *regs)
39 return do_sigaltstack(uss, uoss, regs->sp);
43 struct siginfo *pinfo;
47 unsigned char retcode[16]; /* trampoline code */
50 static int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
54 /* Alwys make any pending restarted system call return -EINTR */
55 current_thread_info()->restart_block.fn = do_no_restart_syscall;
58 * Restore the regs from &sc->regs.
59 * (sc is already checked for VERIFY_READ since the sigframe was
60 * checked in sys_sigreturn previously)
62 if (__copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long)))
64 if (__copy_from_user(®s->pc, &sc->regs.pc, sizeof(unsigned long)))
66 if (__copy_from_user(®s->sr, &sc->regs.sr, sizeof(unsigned long)))
69 /* make sure the SM-bit is cleared so user-mode cannot fool us */
70 regs->sr &= ~SPR_SR_SM;
72 /* TODO: the other ports use regs->orig_XX to disable syscall checks
73 * after this completes, but we don't use that mechanism. maybe we can
83 asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
85 struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp;
90 * Since we stacked the signal on a dword boundary,
91 * then frame should be dword aligned here. If it's
92 * not, then the user is trying to mess with us.
94 if (((long)frame) & 3)
97 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
99 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
102 set_current_blocked(&set);
104 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
107 if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
109 /* It is more difficult to avoid calling this function than to
110 call it and ignore errors. */
111 do_sigaltstack(&st, NULL, regs->sp);
113 return regs->gpr[11];
116 force_sig(SIGSEGV, current);
121 * Set up a signal frame.
124 static int setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
131 err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long));
132 err |= __copy_to_user(&sc->regs.pc, ®s->pc, sizeof(unsigned long));
133 err |= __copy_to_user(&sc->regs.sr, ®s->sr, sizeof(unsigned long));
135 /* then some other stuff */
137 err |= __put_user(mask, &sc->oldmask);
142 static inline unsigned long align_sigframe(unsigned long sp)
148 * Work out where the signal frame should go. It's either on the user stack
149 * or the alternate stack.
152 static inline void __user *get_sigframe(struct k_sigaction *ka,
153 struct pt_regs *regs, size_t frame_size)
155 unsigned long sp = regs->sp;
156 int onsigstack = on_sig_stack(sp);
159 sp -= STACK_FRAME_OVERHEAD;
161 /* This is the X/Open sanctioned signal stack switching. */
162 if ((ka->sa.sa_flags & SA_ONSTACK) && !onsigstack) {
163 if (current->sas_ss_size)
164 sp = current->sas_ss_sp + current->sas_ss_size;
167 sp = align_sigframe(sp - frame_size);
170 * If we are on the alternate signal stack and would overflow it, don't.
171 * Return an always-bogus address instead so we will die with SIGSEGV.
173 if (onsigstack && !likely(on_sig_stack(sp)))
174 return (void __user *)-1L;
176 return (void __user *)sp;
179 /* grab and setup a signal frame.
181 * basically we stack a lot of state info, and arrange for the
182 * user-mode program to return to the kernel using either a
183 * trampoline which performs the syscall sigreturn, or a provided
184 * user-mode trampoline.
186 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
187 sigset_t *set, struct pt_regs *regs)
189 struct rt_sigframe *frame;
190 unsigned long return_ip;
193 frame = get_sigframe(ka, regs, sizeof(*frame));
195 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
198 err |= __put_user(&frame->info, &frame->pinfo);
199 err |= __put_user(&frame->uc, &frame->puc);
201 if (ka->sa.sa_flags & SA_SIGINFO)
202 err |= copy_siginfo_to_user(&frame->info, info);
206 /* Clear all the bits of the ucontext we don't use. */
207 err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
208 err |= __put_user(0, &frame->uc.uc_flags);
209 err |= __put_user(NULL, &frame->uc.uc_link);
210 err |= __put_user((void *)current->sas_ss_sp,
211 &frame->uc.uc_stack.ss_sp);
212 err |= __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags);
213 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
214 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
216 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
221 /* trampoline - the desired return ip is the retcode itself */
222 return_ip = (unsigned long)&frame->retcode;
223 /* This is l.ori r11,r0,__NR_sigreturn, l.sys 1 */
224 err |= __put_user(0xa960, (short *)(frame->retcode + 0));
225 err |= __put_user(__NR_rt_sigreturn, (short *)(frame->retcode + 2));
226 err |= __put_user(0x20000001, (unsigned long *)(frame->retcode + 4));
227 err |= __put_user(0x15000000, (unsigned long *)(frame->retcode + 8));
232 /* TODO what is the current->exec_domain stuff and invmap ? */
234 /* Set up registers for signal handler */
235 regs->pc = (unsigned long)ka->sa.sa_handler; /* what we enter NOW */
236 regs->gpr[9] = (unsigned long)return_ip; /* what we enter LATER */
237 regs->gpr[3] = (unsigned long)sig; /* arg 1: signo */
238 regs->gpr[4] = (unsigned long)&frame->info; /* arg 2: (siginfo_t*) */
239 regs->gpr[5] = (unsigned long)&frame->uc; /* arg 3: ucontext */
241 /* actually move the usp to reflect the stacked frame */
242 regs->sp = (unsigned long)frame;
247 force_sigsegv(sig, current);
252 handle_signal(unsigned long sig,
253 siginfo_t *info, struct k_sigaction *ka,
254 struct pt_regs *regs)
258 ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
262 signal_delivered(sig, info, ka, regs,
263 test_thread_flag(TIF_SINGLESTEP));
267 * Note that 'init' is a special process: it doesn't get signals it doesn't
268 * want to handle. Thus you cannot kill init even with a SIGKILL even by
271 * Also note that the regs structure given here as an argument, is the latest
272 * pushed pt_regs. It may or may not be the same as the first pushed registers
273 * when the initial usermode->kernelmode transition took place. Therefore
274 * we can use user_mode(regs) to see if we came directly from kernel or user
278 void do_signal(struct pt_regs *regs)
282 struct k_sigaction ka;
285 * We want the common case to go fast, which
286 * is why we may in certain cases get here from
287 * kernel mode. Just return without doing anything
290 if (!user_mode(regs))
293 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
295 /* If we are coming out of a syscall then we need
296 * to check if the syscall was interrupted and wants to be
297 * restarted after handling the signal. If so, the original
298 * syscall number is put back into r11 and the PC rewound to
299 * point at the l.sys instruction that resulted in the
300 * original syscall. Syscall results other than the four
301 * below mean that the syscall executed to completion and no
302 * restart is necessary.
304 if (regs->orig_gpr11) {
307 switch (regs->gpr[11]) {
308 case -ERESTART_RESTARTBLOCK:
309 case -ERESTARTNOHAND:
310 /* Restart if there is no signal handler */
311 restart = (signr <= 0);
314 /* Restart if there no signal handler or
315 * SA_RESTART flag is set */
316 restart = (signr <= 0 || (ka.sa.sa_flags & SA_RESTART));
318 case -ERESTARTNOINTR:
325 if (regs->gpr[11] == -ERESTART_RESTARTBLOCK)
326 regs->gpr[11] = __NR_restart_syscall;
328 regs->gpr[11] = regs->orig_gpr11;
331 regs->gpr[11] = -EINTR;
336 /* no signal to deliver so we just put the saved sigmask
338 restore_saved_sigmask();
339 } else { /* signr > 0 */
340 /* Whee! Actually deliver the signal. */
341 handle_signal(signr, &info, &ka, regs);
347 asmlinkage void do_notify_resume(struct pt_regs *regs)
349 if (current_thread_info()->flags & _TIF_SIGPENDING)
352 if (current_thread_info()->flags & _TIF_NOTIFY_RESUME) {
353 clear_thread_flag(TIF_NOTIFY_RESUME);
354 tracehook_notify_resume(regs);