compat_signal.c

linux-2.6.15.6

{
	stack_t kss, koss;
	unsigned long ss_sp;
	int ret, err = 0;
	mm_segment_t old_fs = get_fs();

	if (uss) {
		if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
			return -EFAULT;
		err |= __get_user(ss_sp, &uss->ss_sp);
		err |= __get_user(kss.ss_size, &uss->ss_size);
		err |= __get_user(kss.ss_flags, &uss->ss_flags);
		if (err)
			return -EFAULT;
		kss.ss_sp = (void __user *) ss_sp;
	}

	set_fs (KERNEL_DS);
	ret = do_sigaltstack((stack_t __user *) (uss ? &kss : NULL),
			     (stack_t __user *) (uoss ? &koss : NULL),
			     regs->gprs[15]);
	set_fs (old_fs);

	if (!ret && uoss) {
		if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
			return -EFAULT;
		ss_sp = (unsigned long) koss.ss_sp;
		err |= __put_user(ss_sp, &uoss->ss_sp);
		err |= __put_user(koss.ss_size, &uoss->ss_size);
		err |= __put_user(koss.ss_flags, &uoss->ss_flags);
		if (err)
			return -EFAULT;
	}
	return ret;
}

static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
{
	_s390_regs_common32 regs32;
	int err, i;

	regs32.psw.mask = PSW32_MASK_MERGE(PSW32_USER_BITS,
					   (__u32)(regs->psw.mask >> 32));
	regs32.psw.addr = PSW32_ADDR_AMODE31 | (__u32) regs->psw.addr;
	for (i = 0; i < NUM_GPRS; i++)
		regs32.gprs[i] = (__u32) regs->gprs[i];
	save_access_regs(current->thread.acrs);
	memcpy(regs32.acrs, current->thread.acrs, sizeof(regs32.acrs));
	err = __copy_to_user(&sregs->regs, &regs32, sizeof(regs32));
	if (err)
		return err;
	save_fp_regs(&current->thread.fp_regs);
	/* s390_fp_regs and _s390_fp_regs32 are the same ! */
	return __copy_to_user(&sregs->fpregs, &current->thread.fp_regs,
			      sizeof(_s390_fp_regs32));
}

static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
{
	_s390_regs_common32 regs32;
	int err, i;

	/* Alwys make any pending restarted system call return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	err = __copy_from_user(&regs32, &sregs->regs, sizeof(regs32));
	if (err)
		return err;
	regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask,
				        (__u64)regs32.psw.mask << 32);
	regs->psw.addr = (__u64)(regs32.psw.addr & PSW32_ADDR_INSN);
	for (i = 0; i < NUM_GPRS; i++)
		regs->gprs[i] = (__u64) regs32.gprs[i];
	memcpy(current->thread.acrs, regs32.acrs, sizeof(current->thread.acrs));
	restore_access_regs(current->thread.acrs);

	err = __copy_from_user(&current->thread.fp_regs, &sregs->fpregs,
			       sizeof(_s390_fp_regs32));
	current->thread.fp_regs.fpc &= FPC_VALID_MASK;
	if (err)
		return err;

	restore_fp_regs(&current->thread.fp_regs);
	regs->trap = -1;	/* disable syscall checks */
	return 0;
}

asmlinkage long sys32_sigreturn(struct pt_regs *regs)
{
	sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
	sigset_t set;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigregs32(regs, &frame->sregs))
		goto badframe;

	return regs->gprs[2];

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

asmlinkage long sys32_rt_sigreturn(struct pt_regs *regs)
{
	rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
	sigset_t set;
	stack_t st;
	__u32 ss_sp;
	int err;
	mm_segment_t old_fs = get_fs();

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
		goto badframe;

	err = __get_user(ss_sp, &frame->uc.uc_stack.ss_sp);
	st.ss_sp = compat_ptr(ss_sp);
	err |= __get_user(st.ss_size, &frame->uc.uc_stack.ss_size);
	err |= __get_user(st.ss_flags, &frame->uc.uc_stack.ss_flags);
	if (err)
		goto badframe; 

	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	set_fs (KERNEL_DS);
	do_sigaltstack((stack_t __user *)&st, NULL, regs->gprs[15]);
	set_fs (old_fs);

	return regs->gprs[2];

badframe:
        force_sig(SIGSEGV, current);
        return 0;
}	

/*
 * Set up a signal frame.
 */


/*
 * Determine which stack to use..
 */
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
{
	unsigned long sp;

	/* Default to using normal stack */
	sp = (unsigned long) A(regs->gprs[15]);

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (! on_sig_stack(sp))
			sp = current->sas_ss_sp + current->sas_ss_size;
	}

	/* This is the legacy signal stack switching. */
	else if (!user_mode(regs) &&
		 !(ka->sa.sa_flags & SA_RESTORER) &&
		 ka->sa.sa_restorer) {
		sp = (unsigned long) ka->sa.sa_restorer;
	}

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

static inline int map_signal(int sig)
{
	if (current_thread_info()->exec_domain
	    && current_thread_info()->exec_domain->signal_invmap
	    && sig < 32)
		return current_thread_info()->exec_domain->signal_invmap[sig];
        else
		return sig;
}

static void setup_frame32(int sig, struct k_sigaction *ka,
			sigset_t *set, struct pt_regs * regs)
{
	sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(sigframe32));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe32)))
		goto give_sigsegv;

	if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32))
		goto give_sigsegv;

	if (save_sigregs32(regs, &frame->sregs))
		goto give_sigsegv;
	if (__put_user((unsigned long) &frame->sregs, &frame->sc.sregs))
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		regs->gprs[14] = (__u64) ka->sa.sa_restorer;
	} else {
		regs->gprs[14] = (__u64) frame->retcode;
		if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
		               (u16 __user *)(frame->retcode)))
			goto give_sigsegv;
        }

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (__u64) frame;
	regs->psw.addr = (__u64) ka->sa.sa_handler;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (__u64) &frame->sc;

	/* We forgot to include these in the sigcontext.
	   To avoid breaking binary compatibility, they are passed as args. */
	regs->gprs[4] = current->thread.trap_no;
	regs->gprs[5] = current->thread.prot_addr;

	/* Place signal number on stack to allow backtrace from handler.  */
	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
		goto give_sigsegv;
	return;

give_sigsegv:
	force_sigsegv(sig, current);
}

static void setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs * regs)
{
	int err = 0;
	rt_sigframe32 __user *frame = get_sigframe(ka, regs, sizeof(rt_sigframe32));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe32)))
		goto give_sigsegv;

	if (copy_siginfo_to_user32(&frame->info, info))
		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(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->gprs[15]),
	                  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= save_sigregs32(regs, &frame->uc.uc_mcontext);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	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) {
		regs->gprs[14] = (__u64) ka->sa.sa_restorer;
	} else {
		regs->gprs[14] = (__u64) frame->retcode;
		err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
		                  (u16 __user *)(frame->retcode));
	}

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (__u64) frame;
	regs->psw.addr = (__u64) ka->sa.sa_handler;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (__u64) &frame->info;
	regs->gprs[4] = (__u64) &frame->uc;
	return;

give_sigsegv:
	force_sigsegv(sig, current);
}

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

void
handle_signal32(unsigned long sig, struct k_sigaction *ka,
		siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
{
	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		setup_rt_frame32(sig, ka, info, oldset, regs);
	else
		setup_frame32(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);
}