signal.c

linux-2.6.15.6

static int
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
		 unsigned long mask)
{
	int err = 0;

	/* Do this first, otherwise is this sets sr->fd, that value isn't preserved. */
	err |= setup_sigcontext_fpu(regs, sc);

#define COPY(x)		err |= __put_user(regs->x, &sc->sc_##x)

	COPY(regs[0]);	COPY(regs[1]);	COPY(regs[2]);	COPY(regs[3]);
	COPY(regs[4]);	COPY(regs[5]);	COPY(regs[6]);	COPY(regs[7]);
	COPY(regs[8]);	COPY(regs[9]);	COPY(regs[10]);	COPY(regs[11]);
	COPY(regs[12]);	COPY(regs[13]);	COPY(regs[14]);	COPY(regs[15]);
	COPY(regs[16]);	COPY(regs[17]);	COPY(regs[18]);	COPY(regs[19]);
	COPY(regs[20]);	COPY(regs[21]);	COPY(regs[22]);	COPY(regs[23]);
	COPY(regs[24]);	COPY(regs[25]);	COPY(regs[26]);	COPY(regs[27]);
	COPY(regs[28]);	COPY(regs[29]);	COPY(regs[30]);	COPY(regs[31]);
	COPY(regs[32]);	COPY(regs[33]);	COPY(regs[34]);	COPY(regs[35]);
	COPY(regs[36]);	COPY(regs[37]);	COPY(regs[38]);	COPY(regs[39]);
	COPY(regs[40]);	COPY(regs[41]);	COPY(regs[42]);	COPY(regs[43]);
	COPY(regs[44]);	COPY(regs[45]);	COPY(regs[46]);	COPY(regs[47]);
	COPY(regs[48]);	COPY(regs[49]);	COPY(regs[50]);	COPY(regs[51]);
	COPY(regs[52]);	COPY(regs[53]);	COPY(regs[54]);	COPY(regs[55]);
	COPY(regs[56]);	COPY(regs[57]);	COPY(regs[58]);	COPY(regs[59]);
	COPY(regs[60]);	COPY(regs[61]);	COPY(regs[62]);
	COPY(tregs[0]);	COPY(tregs[1]);	COPY(tregs[2]);	COPY(tregs[3]);
	COPY(tregs[4]);	COPY(tregs[5]);	COPY(tregs[6]);	COPY(tregs[7]);
	COPY(sr);	COPY(pc);

#undef COPY

	err |= __put_user(mask, &sc->oldmask);

	return err;
}

/*
 * Determine which stack to use..
 */
static inline void __user *
get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
{
	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp))
		sp = current->sas_ss_sp + current->sas_ss_size;

	return (void __user *)((sp - frame_size) & -8ul);
}

void sa_default_restorer(void);		/* See comments below */
void sa_default_rt_restorer(void);	/* See comments below */

static void setup_frame(int sig, struct k_sigaction *ka,
			sigset_t *set, struct pt_regs *regs)
{
	struct sigframe __user *frame;
	int err = 0;
	int signal;

	frame = get_sigframe(ka, regs->regs[REG_SP], sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	if (_NSIG_WORDS > 1) {
		err |= __copy_to_user(frame->extramask, &set->sig[1],
				      sizeof(frame->extramask)); }

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1;

		/*
		 * On SH5 all edited pointers are subject to NEFF
		 */
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
	} else {
		/*
		 * Different approach on SH5.
	         * . Endianness independent asm code gets placed in entry.S .
		 *   This is limited to four ASM instructions corresponding
		 *   to two long longs in size.
		 * . err checking is done on the else branch only
		 * . flush_icache_range() is called upon __put_user() only
		 * . all edited pointers are subject to NEFF
		 * . being code, linker turns ShMedia bit on, always
		 *   dereference index -1.
		 */
		DEREF_REG_PR = (unsigned long) frame->retcode | 0x01;
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;

		if (__copy_to_user(frame->retcode,
			(unsigned long long)sa_default_restorer & (~1), 16) != 0)
			goto give_sigsegv;

		/* Cohere the trampoline with the I-cache. */
		flush_cache_sigtramp(DEREF_REG_PR-1, DEREF_REG_PR-1+16);
	}

	/*
	 * Set up registers for signal handler.
	 * All edited pointers are subject to NEFF.
	 */
	regs->regs[REG_SP] = (unsigned long) frame;
	regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ?
        		 (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP];
	regs->regs[REG_ARG1] = signal; /* Arg for signal handler */

        /* FIXME:
           The glibc profiling support for SH-5 needs to be passed a sigcontext
           so it can retrieve the PC.  At some point during 2003 the glibc
           support was changed to receive the sigcontext through the 2nd
           argument, but there are still versions of libc.so in use that use
           the 3rd argument.  Until libc.so is stabilised, pass the sigcontext
           through both 2nd and 3rd arguments.
        */

	regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
	regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->sc;

	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc;

	set_fs(USER_DS);

#if DEBUG_SIG
	/* Broken %016Lx */
	printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
		signal,
		current->comm, current->pid, frame,
		regs->pc >> 32, regs->pc & 0xffffffff,
		DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
#endif

	return;

give_sigsegv:
	force_sigsegv(sig, current);
}

static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	int err = 0;
	int signal;

	frame = get_sigframe(ka, regs->regs[REG_SP], sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	err |= copy_siginfo_to_user(&frame->info, info);

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user((void *)current->sas_ss_sp,
			  &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->regs[REG_SP]),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext,
			        regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1;

		/*
		 * On SH5 all edited pointers are subject to NEFF
		 */
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
	} else {
		/*
		 * Different approach on SH5.
	         * . Endianness independent asm code gets placed in entry.S .
		 *   This is limited to four ASM instructions corresponding
		 *   to two long longs in size.
		 * . err checking is done on the else branch only
		 * . flush_icache_range() is called upon __put_user() only
		 * . all edited pointers are subject to NEFF
		 * . being code, linker turns ShMedia bit on, always
		 *   dereference index -1.
		 */

		DEREF_REG_PR = (unsigned long) frame->retcode | 0x01;
		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
        		 	(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;

		if (__copy_to_user(frame->retcode,
			(unsigned long long)sa_default_rt_restorer & (~1), 16) != 0)
			goto give_sigsegv;

		flush_icache_range(DEREF_REG_PR-1, DEREF_REG_PR-1+15);
	}

	/*
	 * Set up registers for signal handler.
	 * All edited pointers are subject to NEFF.
	 */
	regs->regs[REG_SP] = (unsigned long) frame;
	regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ?
        		 (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP];
	regs->regs[REG_ARG1] = signal; /* Arg for signal handler */
	regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->info;
	regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->uc.uc_mcontext;
	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc;

	set_fs(USER_DS);

#if DEBUG_SIG
	/* Broken %016Lx */
	printk("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
		signal,
		current->comm, current->pid, frame,
		regs->pc >> 32, regs->pc & 0xffffffff,
		DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
#endif

	return;

give_sigsegv:
	force_sigsegv(sig, current);
}

/*
 * OK, we're invoking a handler
 */

static void
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
		sigset_t *oldset, struct pt_regs * regs)
{
	/* Are we from a system call? */
	if (regs->syscall_nr >= 0) {
		/* If so, check system call restarting.. */
		switch (regs->regs[REG_RET]) {
			case -ERESTARTNOHAND:
				regs->regs[REG_RET] = -EINTR;
				break;

			case -ERESTARTSYS:
				if (!(ka->sa.sa_flags & SA_RESTART)) {
					regs->regs[REG_RET] = -EINTR;
					break;
				}
			/* fallthrough */
			case -ERESTARTNOINTR:
				/* Decode syscall # */
				regs->regs[REG_RET] = regs->syscall_nr;
				regs->pc -= 4;
		}
	}

	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		setup_rt_frame(sig, ka, info, oldset, regs);
	else
		setup_frame(sig, ka, oldset, regs);

	spin_lock_irq(&current->sighand->siglock);
	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
	if (!(ka->sa.sa_flags & SA_NODEFER))
		sigaddset(&current->blocked,sig);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 *
 * Note that we go through the signals twice: once to check the signals that
 * the kernel can handle, and then we build all the user-level signal handling
 * stack-frames in one go after that.
 */
int do_signal(struct pt_regs *regs, sigset_t *oldset)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;

	/*
	 * We want the common case to go fast, which
	 * is why we may in certain cases get here from
	 * kernel mode. Just return without doing anything
	 * if so.
	 */
	if (!user_mode(regs))
		return 1;

	if (try_to_freeze())
		goto no_signal;

	if (!oldset)
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, 0);

	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
		handle_signal(signr, &info, &ka, oldset, regs);
		return 1;
	}

no_signal:
	/* Did we come from a system call? */
	if (regs->syscall_nr >= 0) {
		/* Restart the system call - no handlers present */
		if (regs->regs[REG_RET] == -ERESTARTNOHAND ||
		    regs->regs[REG_RET] == -ERESTARTSYS ||
		    regs->regs[REG_RET] == -ERESTARTNOINTR) {
			/* Decode Syscall # */
			regs->regs[REG_RET] = regs->syscall_nr;
			regs->pc -= 4;
		}
	}
	return 0;
}