static int dwarf_parse_fde()

in kernel/dwarf.c [865:955]

• 64 lines of code
• 9 McCabe index (conditional complexity)

static int dwarf_parse_fde(void *entry, u32 entry_type,
			   void *start, unsigned long len,
			   unsigned char *end, struct module *mod)
{
	struct rb_node **rb_node = &fde_root.rb_node;
	struct rb_node *parent = *rb_node;
	struct dwarf_fde *fde;
	struct dwarf_cie *cie;
	unsigned long flags;
	int count;
	void *p = start;

	fde = kzalloc(sizeof(*fde), GFP_KERNEL);
	if (!fde)
		return -ENOMEM;

	fde->length = len;

	/*
	 * In a .eh_frame section the CIE pointer is the
	 * delta between the address within the FDE
	 */
	fde->cie_pointer = (unsigned long)(p - entry_type - 4);

	cie = dwarf_lookup_cie(fde->cie_pointer);
	fde->cie = cie;

	if (cie->encoding)
		count = dwarf_read_encoded_value(p, &fde->initial_location,
						 cie->encoding);
	else
		count = dwarf_read_addr(p, &fde->initial_location);

	p += count;

	if (cie->encoding)
		count = dwarf_read_encoded_value(p, &fde->address_range,
						 cie->encoding & 0x0f);
	else
		count = dwarf_read_addr(p, &fde->address_range);

	p += count;

	if (fde->cie->flags & DWARF_CIE_Z_AUGMENTATION) {
		unsigned int length;
		count = dwarf_read_uleb128(p, &length);
		p += count + length;
	}

	/* Call frame instructions. */
	fde->instructions = p;
	fde->end = end;

	/* Add to list. */
	spin_lock_irqsave(&dwarf_fde_lock, flags);

	while (*rb_node) {
		struct dwarf_fde *fde_tmp;
		unsigned long tmp_start, tmp_end;
		unsigned long start, end;

		fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node);

		start = fde->initial_location;
		end = fde->initial_location + fde->address_range;

		tmp_start = fde_tmp->initial_location;
		tmp_end = fde_tmp->initial_location + fde_tmp->address_range;

		parent = *rb_node;

		if (start < tmp_start)
			rb_node = &parent->rb_left;
		else if (start >= tmp_end)
			rb_node = &parent->rb_right;
		else
			WARN_ON(1);
	}

	rb_link_node(&fde->node, parent, rb_node);
	rb_insert_color(&fde->node, &fde_root);

#ifdef CONFIG_MODULES
	if (mod != NULL)
		list_add_tail(&fde->link, &mod->arch.fde_list);
#endif

	spin_unlock_irqrestore(&dwarf_fde_lock, flags);

	return 0;
}