Beispiel #1
0
/*
 * 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.
 */
void do_signal(struct pt_regs *regs)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	sigset_t *oldset = sigmask_to_save();

	/*
	 * Get signal to deliver. When running under ptrace, at this point
	 * the debugger may change all our registers, including the system
	 * call information.
	 */
	current_thread_info()->system_call =
		test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
		if (current_thread_info()->system_call) {
			regs->int_code = current_thread_info()->system_call;
			/* Check for system call restarting. */
			switch (regs->gprs[2]) {
			case -ERESTART_RESTARTBLOCK:
			case -ERESTARTNOHAND:
				regs->gprs[2] = -EINTR;
				break;
			case -ERESTARTSYS:
				if (!(ka.sa.sa_flags & SA_RESTART)) {
					regs->gprs[2] = -EINTR;
					break;
				}
			/* fallthrough */
			case -ERESTARTNOINTR:
				regs->gprs[2] = regs->orig_gpr2;
				regs->psw.addr =
					__rewind_psw(regs->psw,
						     regs->int_code >> 16);
				break;
			}
		}
		/* No longer in a system call */
		clear_pt_regs_flag(regs, PIF_SYSCALL);

		if (is_compat_task())
			handle_signal32(signr, &ka, &info, oldset, regs);
		else
			handle_signal(signr, &ka, &info, oldset, regs);
		return;
	}
Beispiel #2
0
int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
	if (psw_bits(regs->psw).eaba == PSW_BITS_AMODE_24BIT)
		return -EINVAL;
	if (!is_compat_task() && psw_bits(regs->psw).eaba == PSW_BITS_AMODE_31BIT)
		return -EINVAL;
	clear_pt_regs_flag(regs, PIF_PER_TRAP);
	auprobe->saved_per = psw_bits(regs->psw).per;
	auprobe->saved_int_code = regs->int_code;
	regs->int_code = UPROBE_TRAP_NR;
	regs->psw.addr = current->utask->xol_vaddr;
	set_tsk_thread_flag(current, TIF_UPROBE_SINGLESTEP);
	update_cr_regs(current);
	return 0;
}
Beispiel #3
0
void data_exception(struct pt_regs *regs)
{
    __u16 __user *location;
    int signal = 0;

    location = get_trap_ip(regs);

    save_fpu_regs();
    /* Check for vector register enablement */
    if (MACHINE_HAS_VX && !is_vx_task(current) &&
            (current->thread.fpu.fpc & FPC_DXC_MASK) == 0xfe00) {
        alloc_vector_registers(current);
        /* Vector data exception is suppressing, rewind psw. */
        regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16);
        clear_pt_regs_flag(regs, PIF_PER_TRAP);
        return;
    }
Beispiel #4
0
static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
	_sigregs user_sregs;

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

	if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
		return -EFAULT;

	if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
		return -EINVAL;

	/* Loading the floating-point-control word can fail. Do that first. */
	if (restore_fp_ctl(&user_sregs.fpregs.fpc))
		return -EINVAL;

	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
	regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
		(user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
	/* Check for invalid user address space control. */
	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
		regs->psw.mask = PSW_ASC_PRIMARY |
			(regs->psw.mask & ~PSW_MASK_ASC);
	/* Check for invalid amode */
	if (regs->psw.mask & PSW_MASK_EA)
		regs->psw.mask |= PSW_MASK_BA;
	regs->psw.addr = user_sregs.regs.psw.addr;
	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	       sizeof(current->thread.acrs));
	restore_access_regs(current->thread.acrs);

	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
	       sizeof(current->thread.fp_regs));

	restore_fp_regs(current->thread.fp_regs.fprs);
	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
	return 0;
}
static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
{
    _sigregs32 user_sregs;
    int i;

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

    if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
        return -EFAULT;

    if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
        return -EINVAL;

    /* Loading the floating-point-control word can fail. Do that first. */
    if (restore_fp_ctl(&user_sregs.fpregs.fpc))
        return -EINVAL;

    /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
    regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
                     (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
                     (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 |
                     (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
    /* Check for invalid user address space control. */
    if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
        regs->psw.mask = PSW_ASC_PRIMARY |
                         (regs->psw.mask & ~PSW_MASK_ASC);
    regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
    for (i = 0; i < NUM_GPRS; i++)
        regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
    memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
           sizeof(current->thread.acrs));

    memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
           sizeof(current->thread.fp_regs));

    clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
    return 0;
}
Beispiel #6
0
/*
 * This routine handles page faults.  It determines the address,
 * and the problem, and then passes it off to one of the appropriate
 * routines.
 *
 * interruption code (int_code):
 *   04       Protection           ->  Write-Protection  (suprression)
 *   10       Segment translation  ->  Not present       (nullification)
 *   11       Page translation     ->  Not present       (nullification)
 *   3b       Region third trans.  ->  Not present       (nullification)
 */
static inline int do_exception(struct pt_regs *regs, int access)
{
	struct gmap *gmap;
	struct task_struct *tsk;
	struct mm_struct *mm;
	struct vm_area_struct *vma;
	enum fault_type type;
	unsigned long trans_exc_code;
	unsigned long address;
	unsigned int flags;
	int fault;

	tsk = current;
	/*
	 * The instruction that caused the program check has
	 * been nullified. Don't signal single step via SIGTRAP.
	 */
	clear_pt_regs_flag(regs, PIF_PER_TRAP);

	if (notify_page_fault(regs))
		return 0;

	mm = tsk->mm;
	trans_exc_code = regs->int_parm_long;

	/*
	 * Verify that the fault happened in user space, that
	 * we are not in an interrupt and that there is a 
	 * user context.
	 */
	fault = VM_FAULT_BADCONTEXT;
	type = get_fault_type(regs);
	switch (type) {
	case KERNEL_FAULT:
		goto out;
	case VDSO_FAULT:
		fault = VM_FAULT_BADMAP;
		goto out;
	case USER_FAULT:
	case GMAP_FAULT:
		if (faulthandler_disabled() || !mm)
			goto out;
		break;
	}

	address = trans_exc_code & __FAIL_ADDR_MASK;
	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
	flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
	if (user_mode(regs))
		flags |= FAULT_FLAG_USER;
	if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400)
		flags |= FAULT_FLAG_WRITE;
	down_read(&mm->mmap_sem);

	gmap = NULL;
	if (IS_ENABLED(CONFIG_PGSTE) && type == GMAP_FAULT) {
		gmap = (struct gmap *) S390_lowcore.gmap;
		current->thread.gmap_addr = address;
		current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE);
		current->thread.gmap_int_code = regs->int_code & 0xffff;
		address = __gmap_translate(gmap, address);
		if (address == -EFAULT) {
			fault = VM_FAULT_BADMAP;
			goto out_up;
		}
		if (gmap->pfault_enabled)
			flags |= FAULT_FLAG_RETRY_NOWAIT;
	}

retry:
	fault = VM_FAULT_BADMAP;
	vma = find_vma(mm, address);
	if (!vma)
		goto out_up;

	if (unlikely(vma->vm_start > address)) {
		if (!(vma->vm_flags & VM_GROWSDOWN))
			goto out_up;
		if (expand_stack(vma, address))
			goto out_up;
	}

	/*
	 * Ok, we have a good vm_area for this memory access, so
	 * we can handle it..
	 */
	fault = VM_FAULT_BADACCESS;
	if (unlikely(!(vma->vm_flags & access)))
		goto out_up;

	if (is_vm_hugetlb_page(vma))
		address &= HPAGE_MASK;
	/*
	 * If for any reason at all we couldn't handle the fault,
	 * make sure we exit gracefully rather than endlessly redo
	 * the fault.
	 */
	fault = handle_mm_fault(vma, address, flags);
	/* No reason to continue if interrupted by SIGKILL. */
	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) {
		fault = VM_FAULT_SIGNAL;
		goto out;
	}
	if (unlikely(fault & VM_FAULT_ERROR))
		goto out_up;

	/*
	 * Major/minor page fault accounting is only done on the
	 * initial attempt. If we go through a retry, it is extremely
	 * likely that the page will be found in page cache at that point.
	 */
	if (flags & FAULT_FLAG_ALLOW_RETRY) {
		if (fault & VM_FAULT_MAJOR) {
			tsk->maj_flt++;
			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
				      regs, address);
		} else {
			tsk->min_flt++;
			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
				      regs, address);
		}
		if (fault & VM_FAULT_RETRY) {
			if (IS_ENABLED(CONFIG_PGSTE) && gmap &&
			    (flags & FAULT_FLAG_RETRY_NOWAIT)) {
				/* FAULT_FLAG_RETRY_NOWAIT has been set,
				 * mmap_sem has not been released */
				current->thread.gmap_pfault = 1;
				fault = VM_FAULT_PFAULT;
				goto out_up;
			}
			/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
			 * of starvation. */
			flags &= ~(FAULT_FLAG_ALLOW_RETRY |
				   FAULT_FLAG_RETRY_NOWAIT);
			flags |= FAULT_FLAG_TRIED;
			down_read(&mm->mmap_sem);
			goto retry;
		}
	}
	if (IS_ENABLED(CONFIG_PGSTE) && gmap) {
		address =  __gmap_link(gmap, current->thread.gmap_addr,
				       address);
		if (address == -EFAULT) {
			fault = VM_FAULT_BADMAP;
			goto out_up;
		}
		if (address == -ENOMEM) {
			fault = VM_FAULT_OOM;
			goto out_up;
		}
	}
	fault = 0;
out_up:
	up_read(&mm->mmap_sem);
out:
	return fault;
}