PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies

In a struct pcie_link_state, link->root points to the pcie_link_state of
the root of the PCIe hierarchy.  For the topmost link, this points to
itself (link->root = link).  For others, we copy the pointer from the
parent (link->root = link->parent->root).

Previously we recognized that Root Ports originated PCIe hierarchies, but
we treated PCI/PCI-X to PCIe Bridges as being in the middle of the
hierarchy, and when we tried to copy the pointer from link->parent->root,
there was no parent, and we dereferenced a NULL pointer:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
  IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820

Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just
like Root Ports do, so link->root for these devices should also point to
itself.

Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181
Tested-by: lists@ssl-mail.com
Tested-by: Jayachandran C. <jnair@caviumnetworks.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v4.2+

path: root/screen.h

#ifndef SCREEN_H
#define SCREEN_H

#include <curses.h>

enum colors {
	BLACK   = COLOR_BLACK,
	RED     = COLOR_RED,
	GREEN   = COLOR_GREEN,
	YELLOW  = COLOR_YELLOW,
	BLUE    = COLOR_BLUE,
	MAGENTA = COLOR_MAGENTA,
	CYAN    = COLOR_CYAN,
	WHITE   = COLOR_WHITE,
};

#define COLOR_MASK(fg, bg) ((fg) + (bg) * (COLOR_WHITE + 1))
#define COLOR(fg, bg) COLOR_PAIR(COLOR_MASK((fg), (bg)))
#define INIT_COLOR(fg, bg) init_pair(COLOR_MASK((fg), (bg)), (fg), (bg))
#define COLOR_ON(fg, bg) attron(COLOR(fg, bg))
#define COLOR_OFF(fg, bg) attroff(COLOR(fg, bg))

extern WINDOW *screen_init(bool israw);
extern void screen_end(void);

#endif /* SCREEN_H */