linux/drivers/pci/hotplug/acpiphp.h

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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* ACPI PCI Hot Plug Controller Driver
*
* Copyright (C) 1995,2001 Compaq Computer Corporation
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001 IBM Corp.
* Copyright (C) 2002 Hiroshi Aono (h-aono@ap.jp.nec.com)
* Copyright (C) 2002,2003 Takayoshi Kochi (t-kochi@bq.jp.nec.com)
* Copyright (C) 2002,2003 NEC Corporation
* Copyright (C) 2003-2005 Matthew Wilcox (willy@infradead.org)
* Copyright (C) 2003-2005 Hewlett Packard
*
* All rights reserved.
*
* Send feedback to <gregkh@us.ibm.com>,
* <t-kochi@bq.jp.nec.com>
*
*/
#ifndef _ACPIPHP_H
#define _ACPIPHP_H
#include <linux/acpi.h>
#include <linux/mutex.h>
#include <linux/pci_hotplug.h>
struct acpiphp_context;
struct acpiphp_bridge;
struct acpiphp_slot;
/*
* struct slot - slot information for each *physical* slot
*/
struct slot {
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>
2018-09-08 07:59:01 +00:00
struct hotplug_slot hotplug_slot;
struct acpiphp_slot *acpi_slot;
unsigned int sun; /* ACPI _SUN (Slot User Number) value */
};
static inline const char *slot_name(struct slot *slot)
{
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>
2018-09-08 07:59:01 +00:00
return hotplug_slot_name(&slot->hotplug_slot);
}
static inline struct slot *to_slot(struct hotplug_slot *hotplug_slot)
{
return container_of(hotplug_slot, struct slot, hotplug_slot);
}
/*
* struct acpiphp_bridge - PCI bridge information
*
* for each bridge device in ACPI namespace
*/
struct acpiphp_bridge {
struct list_head list;
struct list_head slots;
struct kref ref;
struct acpiphp_context *context;
int nr_slots;
/* This bus (host bridge) or Secondary bus (PCI-to-PCI bridge) */
struct pci_bus *pci_bus;
/* PCI-to-PCI bridge device */
struct pci_dev *pci_dev;
bool is_going_away;
};
/*
* struct acpiphp_slot - PCI slot information
*
* PCI slot information for each *physical* PCI slot
*/
struct acpiphp_slot {
struct list_head node;
struct pci_bus *bus;
struct list_head funcs; /* one slot may have different
objects (i.e. for each function) */
struct slot *slot;
u8 device; /* pci device# */
u32 flags; /* see below */
};
/*
* struct acpiphp_func - PCI function information
*
* PCI function information for each object in ACPI namespace
* typically 8 objects per slot (i.e. for each PCI function)
*/
struct acpiphp_func {
struct acpiphp_bridge *parent;
struct acpiphp_slot *slot;
struct list_head sibling;
u8 function; /* pci function# */
u32 flags; /* see below */
};
struct acpiphp_context {
ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug The ACPI-based PCI hotplug (ACPIPHP) code currently attaches its hotplug context objects directly to ACPI namespace nodes representing hotplug devices. However, after recent changes causing struct acpi_device to be created for every namespace node representing a device (regardless of its status), that is not necessary any more. Moreover, it's vulnerable to the theoretical issue that the ACPI handle passed in the context between handle_hotplug_event() and hotplug_event_work() may become invalid in the meantime (as a result of a concurrent table unload). In principle, this issue might be addressed by adding a non-empty release handler for ACPIPHP hotplug context objects analogous to acpi_scan_drop_device(), but that would duplicate the code in that function and in acpi_device_del_work_fn(). For this reason, it's better to modify ACPIPHP to attach its device hotplug contexts to struct device objects representing hotplug devices and make it use acpi_hotplug_notify_cb() as its notify handler. At the same time, acpi_device_hotplug() can be modified to dispatch the new .hp.event() callback pointing to acpiphp_hotplug_event() from ACPI device objects associated with PCI devices or use the generic ACPI device hotplug code for device objects with matching scan handlers. This allows the existing code duplication between ACPIPHP and the ACPI core to be reduced too and makes further ACPI-based device hotplug consolidation possible. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-06 16:31:37 +00:00
struct acpi_hotplug_context hp;
struct acpiphp_func func;
struct acpiphp_bridge *bridge;
unsigned int refcount;
};
ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug The ACPI-based PCI hotplug (ACPIPHP) code currently attaches its hotplug context objects directly to ACPI namespace nodes representing hotplug devices. However, after recent changes causing struct acpi_device to be created for every namespace node representing a device (regardless of its status), that is not necessary any more. Moreover, it's vulnerable to the theoretical issue that the ACPI handle passed in the context between handle_hotplug_event() and hotplug_event_work() may become invalid in the meantime (as a result of a concurrent table unload). In principle, this issue might be addressed by adding a non-empty release handler for ACPIPHP hotplug context objects analogous to acpi_scan_drop_device(), but that would duplicate the code in that function and in acpi_device_del_work_fn(). For this reason, it's better to modify ACPIPHP to attach its device hotplug contexts to struct device objects representing hotplug devices and make it use acpi_hotplug_notify_cb() as its notify handler. At the same time, acpi_device_hotplug() can be modified to dispatch the new .hp.event() callback pointing to acpiphp_hotplug_event() from ACPI device objects associated with PCI devices or use the generic ACPI device hotplug code for device objects with matching scan handlers. This allows the existing code duplication between ACPIPHP and the ACPI core to be reduced too and makes further ACPI-based device hotplug consolidation possible. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-06 16:31:37 +00:00
static inline struct acpiphp_context *to_acpiphp_context(struct acpi_hotplug_context *hp)
{
return container_of(hp, struct acpiphp_context, hp);
}
static inline struct acpiphp_context *func_to_context(struct acpiphp_func *func)
{
return container_of(func, struct acpiphp_context, func);
}
static inline struct acpi_device *func_to_acpi_device(struct acpiphp_func *func)
{
ACPI / hotplug / PCI: Consolidate ACPIPHP with ACPI core hotplug The ACPI-based PCI hotplug (ACPIPHP) code currently attaches its hotplug context objects directly to ACPI namespace nodes representing hotplug devices. However, after recent changes causing struct acpi_device to be created for every namespace node representing a device (regardless of its status), that is not necessary any more. Moreover, it's vulnerable to the theoretical issue that the ACPI handle passed in the context between handle_hotplug_event() and hotplug_event_work() may become invalid in the meantime (as a result of a concurrent table unload). In principle, this issue might be addressed by adding a non-empty release handler for ACPIPHP hotplug context objects analogous to acpi_scan_drop_device(), but that would duplicate the code in that function and in acpi_device_del_work_fn(). For this reason, it's better to modify ACPIPHP to attach its device hotplug contexts to struct device objects representing hotplug devices and make it use acpi_hotplug_notify_cb() as its notify handler. At the same time, acpi_device_hotplug() can be modified to dispatch the new .hp.event() callback pointing to acpiphp_hotplug_event() from ACPI device objects associated with PCI devices or use the generic ACPI device hotplug code for device objects with matching scan handlers. This allows the existing code duplication between ACPIPHP and the ACPI core to be reduced too and makes further ACPI-based device hotplug consolidation possible. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-02-06 16:31:37 +00:00
return func_to_context(func)->hp.self;
}
static inline acpi_handle func_to_handle(struct acpiphp_func *func)
{
return func_to_acpi_device(func)->handle;
}
struct acpiphp_root_context {
struct acpi_hotplug_context hp;
struct acpiphp_bridge *root_bridge;
};
static inline struct acpiphp_root_context *to_acpiphp_root_context(struct acpi_hotplug_context *hp)
{
return container_of(hp, struct acpiphp_root_context, hp);
}
/*
* struct acpiphp_attention_info - device specific attention registration
*
* ACPI has no generic method of setting/getting attention status
* this allows for device specific driver registration
*/
struct acpiphp_attention_info
{
int (*set_attn)(struct hotplug_slot *slot, u8 status);
int (*get_attn)(struct hotplug_slot *slot, u8 *status);
struct module *owner;
};
/* ACPI _STA method value (ignore bit 4; battery present) */
#define ACPI_STA_ALL (0x0000000f)
/* slot flags */
#define SLOT_ENABLED (0x00000001)
#define SLOT_IS_GOING_AWAY (0x00000002)
/* function flags */
#define FUNC_HAS_STA (0x00000001)
#define FUNC_HAS_EJ0 (0x00000002)
/* function prototypes */
/* acpiphp_core.c */
int acpiphp_register_attention(struct acpiphp_attention_info *info);
int acpiphp_unregister_attention(struct acpiphp_attention_info *info);
int acpiphp_register_hotplug_slot(struct acpiphp_slot *slot, unsigned int sun);
void acpiphp_unregister_hotplug_slot(struct acpiphp_slot *slot);
/* acpiphp_glue.c */
typedef int (*acpiphp_callback)(struct acpiphp_slot *slot, void *data);
int acpiphp_enable_slot(struct acpiphp_slot *slot);
int acpiphp_disable_slot(struct acpiphp_slot *slot);
u8 acpiphp_get_power_status(struct acpiphp_slot *slot);
u8 acpiphp_get_attention_status(struct acpiphp_slot *slot);
u8 acpiphp_get_latch_status(struct acpiphp_slot *slot);
u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot);
/* variables */
extern bool acpiphp_disabled;
#endif /* _ACPIPHP_H */