alistair23-linux/include/linux/pci_hotplug.h
Lukas Wunner 125450f814 PCI: hotplug: Embed hotplug_slot
When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its internal use plus a hotplug_slot struct to be registered
with the hotplug core and linked the two with pointers:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Nowadays, the predominant pattern in the tree is to embed ("subclass")
such structures in one another and cast to the containing struct with
container_of().  But it wasn't until July 2002 that container_of() was
introduced with historic commit ec4f214232cf:
https://git.kernel.org/tglx/history/c/ec4f214232cf

pnv_php, introduced in 2016, did the right thing and embedded struct
hotplug_slot in its internal struct pnv_php_slot, but all other drivers
cargo-culted cpqphp's design and linked separate structs with pointers.

Embedding structs is preferrable to linking them with pointers because
it requires fewer allocations, thereby reducing overhead and simplifying
error paths.  Casting an embedded struct to the containing struct
becomes a cheap subtraction rather than a dereference.  And having fewer
pointers reduces the risk of them pointing nowhere either accidentally
or due to an attack.

Convert all drivers to embed struct hotplug_slot in their internal slot
struct.  The "private" pointer in struct hotplug_slot thereby becomes
unused, so drop it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>  # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com>        # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
2018-09-18 17:52:15 -05:00

164 lines
5.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* PCI HotPlug Core Functions
*
* Copyright (C) 1995,2001 Compaq Computer Corporation
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001 IBM Corp.
*
* All rights reserved.
*
* Send feedback to <kristen.c.accardi@intel.com>
*
*/
#ifndef _PCI_HOTPLUG_H
#define _PCI_HOTPLUG_H
/**
* struct hotplug_slot_ops -the callbacks that the hotplug pci core can use
* @enable_slot: Called when the user wants to enable a specific pci slot
* @disable_slot: Called when the user wants to disable a specific pci slot
* @set_attention_status: Called to set the specific slot's attention LED to
* the specified value
* @hardware_test: Called to run a specified hardware test on the specified
* slot.
* @get_power_status: Called to get the current power status of a slot.
* @get_attention_status: Called to get the current attention status of a slot.
* @get_latch_status: Called to get the current latch status of a slot.
* @get_adapter_status: Called to get see if an adapter is present in the slot or not.
* @reset_slot: Optional interface to allow override of a bus reset for the
* slot for cases where a secondary bus reset can result in spurious
* hotplug events or where a slot can be reset independent of the bus.
*
* The table of function pointers that is passed to the hotplug pci core by a
* hotplug pci driver. These functions are called by the hotplug pci core when
* the user wants to do something to a specific slot (query it for information,
* set an LED, enable / disable power, etc.)
*/
struct hotplug_slot_ops {
int (*enable_slot) (struct hotplug_slot *slot);
int (*disable_slot) (struct hotplug_slot *slot);
int (*set_attention_status) (struct hotplug_slot *slot, u8 value);
int (*hardware_test) (struct hotplug_slot *slot, u32 value);
int (*get_power_status) (struct hotplug_slot *slot, u8 *value);
int (*get_attention_status) (struct hotplug_slot *slot, u8 *value);
int (*get_latch_status) (struct hotplug_slot *slot, u8 *value);
int (*get_adapter_status) (struct hotplug_slot *slot, u8 *value);
int (*reset_slot) (struct hotplug_slot *slot, int probe);
};
/**
* struct hotplug_slot - used to register a physical slot with the hotplug pci core
* @ops: pointer to the &struct hotplug_slot_ops to be used for this slot
* @owner: The module owner of this structure
* @mod_name: The module name (KBUILD_MODNAME) of this structure
*/
struct hotplug_slot {
const struct hotplug_slot_ops *ops;
/* Variables below this are for use only by the hotplug pci core. */
struct list_head slot_list;
struct pci_slot *pci_slot;
struct module *owner;
const char *mod_name;
};
static inline const char *hotplug_slot_name(const struct hotplug_slot *slot)
{
return pci_slot_name(slot->pci_slot);
}
int __pci_hp_register(struct hotplug_slot *slot, struct pci_bus *pbus, int nr,
const char *name, struct module *owner,
const char *mod_name);
int __pci_hp_initialize(struct hotplug_slot *slot, struct pci_bus *bus, int nr,
const char *name, struct module *owner,
const char *mod_name);
int pci_hp_add(struct hotplug_slot *slot);
void pci_hp_del(struct hotplug_slot *slot);
void pci_hp_destroy(struct hotplug_slot *slot);
void pci_hp_deregister(struct hotplug_slot *slot);
/* use a define to avoid include chaining to get THIS_MODULE & friends */
#define pci_hp_register(slot, pbus, devnr, name) \
__pci_hp_register(slot, pbus, devnr, name, THIS_MODULE, KBUILD_MODNAME)
#define pci_hp_initialize(slot, bus, nr, name) \
__pci_hp_initialize(slot, bus, nr, name, THIS_MODULE, KBUILD_MODNAME)
/* PCI Setting Record (Type 0) */
struct hpp_type0 {
u32 revision;
u8 cache_line_size;
u8 latency_timer;
u8 enable_serr;
u8 enable_perr;
};
/* PCI-X Setting Record (Type 1) */
struct hpp_type1 {
u32 revision;
u8 max_mem_read;
u8 avg_max_split;
u16 tot_max_split;
};
/* PCI Express Setting Record (Type 2) */
struct hpp_type2 {
u32 revision;
u32 unc_err_mask_and;
u32 unc_err_mask_or;
u32 unc_err_sever_and;
u32 unc_err_sever_or;
u32 cor_err_mask_and;
u32 cor_err_mask_or;
u32 adv_err_cap_and;
u32 adv_err_cap_or;
u16 pci_exp_devctl_and;
u16 pci_exp_devctl_or;
u16 pci_exp_lnkctl_and;
u16 pci_exp_lnkctl_or;
u32 sec_unc_err_sever_and;
u32 sec_unc_err_sever_or;
u32 sec_unc_err_mask_and;
u32 sec_unc_err_mask_or;
};
struct hotplug_params {
struct hpp_type0 *t0; /* Type0: NULL if not available */
struct hpp_type1 *t1; /* Type1: NULL if not available */
struct hpp_type2 *t2; /* Type2: NULL if not available */
struct hpp_type0 type0_data;
struct hpp_type1 type1_data;
struct hpp_type2 type2_data;
};
#ifdef CONFIG_ACPI
#include <linux/acpi.h>
int pci_get_hp_params(struct pci_dev *dev, struct hotplug_params *hpp);
bool pciehp_is_native(struct pci_dev *bridge);
int acpi_get_hp_hw_control_from_firmware(struct pci_dev *bridge);
bool shpchp_is_native(struct pci_dev *bridge);
int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle);
int acpi_pci_detect_ejectable(acpi_handle handle);
#else
static inline int pci_get_hp_params(struct pci_dev *dev,
struct hotplug_params *hpp)
{
return -ENODEV;
}
static inline int acpi_get_hp_hw_control_from_firmware(struct pci_dev *bridge)
{
return 0;
}
static inline bool pciehp_is_native(struct pci_dev *bridge) { return true; }
static inline bool shpchp_is_native(struct pci_dev *bridge) { return true; }
#endif
static inline bool hotplug_is_native(struct pci_dev *bridge)
{
return pciehp_is_native(bridge) || shpchp_is_native(bridge);
}
#endif