Subject: [PATCH 2/6] x86, acpi, pci: Move arch-agnostic MMCFG code out of arch/x86/ directory

From: [email-masked] (Bjorn Helgaas)
Date: Wed, 10 Dec 2014 16:35:52 -0700

On Wed, Nov 19, 2014 at 05:04:47PM +0100, Tomasz Nowicki wrote:
> MMCFG table seems to be architecture independent and it makes sense
> to share common code across all architectures. The ones that may need
> architectural specific actions have default prototype (__weak).

We have kind of a stew of abbreviations here: MCFG, MMCFG, MMCONFIG.  In
addition, the "MMCONFIG" term comes is used by ACPI but not by the PCI
specs.  The PCIe spec uses "ECAM" (Enhanced Configuration Access Mechanism)
instead.  If we're going to make this architecture-independent (which I
think is a great idea), I sort of hate to expose it using terms that only
mean something to ACPI folks.  

So I want to moot the idea of replacing the "pci_mmcfg" and "pci_mmconfig"
prefixes with something more generic, like "pci_ecam".  I'm a little bit
conflicted about this, because it would mean a fair amount of churn, but on
the other hand, I do think good names are a huge aid to understanding.

I'm mostly concerned about the things exposed outside of x86.  Things that
are x86-specific or ACPI-specific could be left alone, so maybe it wouldn't
be a huge change.

I noticed you made some functions __weak; I'd like to see that change split
into a separate patch, with this one being basically mechanical code
movement with no functional change.  That way we can discuss the need for
and merits of that approach separately.  A mmcfg->ecam rename (if we do
that) should also be its own separate patch.

Bjorn

> Signed-off-by: Tomasz Nowicki <[email-masked]>
> Tested-by: Hanjun Guo <[email-masked]>
> ---
>  arch/x86/include/asm/pci_x86.h |  29 -----
>  arch/x86/pci/acpi.c            |   1 +
>  arch/x86/pci/init.c            |   1 +
>  arch/x86/pci/mmconfig-shared.c | 200 +---------------------------------
>  arch/x86/pci/mmconfig_32.c     |   1 +
>  arch/x86/pci/mmconfig_64.c     |   1 +
>  drivers/acpi/Makefile          |   1 +
>  drivers/acpi/bus.c             |   1 +
>  drivers/acpi/mmconfig.c        | 242 +++++++++++++++++++++++++++++++++++++++++
>  include/linux/mmconfig.h       |  58 ++++++++++
>  include/linux/pci.h            |   8 --
>  11 files changed, 308 insertions(+), 235 deletions(-)
>  create mode 100644 drivers/acpi/mmconfig.c
>  create mode 100644 include/linux/mmconfig.h
> 
> diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
> index fa1195d..caba141 100644
> --- a/arch/x86/include/asm/pci_x86.h
> +++ b/arch/x86/include/asm/pci_x86.h
> @@ -121,35 +121,6 @@ extern int __init pcibios_init(void);
>  extern int pci_legacy_init(void);
>  extern void pcibios_fixup_irqs(void);
>  
> -/* pci-mmconfig.c */
> -
> -/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
> -#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
> -
> -struct pci_mmcfg_region {
> -	struct list_head list;
> -	struct resource res;
> -	u64 address;
> -	char __iomem *virt;
> -	u16 segment;
> -	u8 start_bus;
> -	u8 end_bus;
> -	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
> -};
> -
> -extern int __init pci_mmcfg_arch_init(void);
> -extern void __init pci_mmcfg_arch_free(void);
> -extern int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg);
> -extern void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg);
> -extern int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
> -			       phys_addr_t addr);
> -extern int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
> -extern struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
> -
> -extern struct list_head pci_mmcfg_list;
> -
> -#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
> -
>  /*
>   * AMD Fam10h CPUs are buggy, and cannot access MMIO config space
>   * on their northbrige except through the * %eax register. As such, you MUST
> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
> index cfd1b13..6d11131 100644
> --- a/arch/x86/pci/acpi.c
> +++ b/arch/x86/pci/acpi.c
> @@ -4,6 +4,7 @@
>  #include <linux/irq.h>
>  #include <linux/dmi.h>
>  #include <linux/slab.h>
> +#include <linux/mmconfig.h>
>  #include <asm/numa.h>
>  #include <asm/pci_x86.h>
>  
> diff --git a/arch/x86/pci/init.c b/arch/x86/pci/init.c
> index adb62aa..b4a55df 100644
> --- a/arch/x86/pci/init.c
> +++ b/arch/x86/pci/init.c
> @@ -1,5 +1,6 @@
>  #include <linux/pci.h>
>  #include <linux/init.h>
> +#include <linux/mmconfig.h>
>  #include <asm/pci_x86.h>
>  #include <asm/x86_init.h>
>  
> diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
> index ac24e1c..b397544 100644
> --- a/arch/x86/pci/mmconfig-shared.c
> +++ b/arch/x86/pci/mmconfig-shared.c
> @@ -18,6 +18,7 @@
>  #include <linux/slab.h>
>  #include <linux/mutex.h>
>  #include <linux/rculist.h>
> +#include <linux/mmconfig.h>
>  #include <asm/e820.h>
>  #include <asm/pci_x86.h>
>  #include <asm/acpi.h>
> @@ -27,103 +28,6 @@
>  /* Indicate if the mmcfg resources have been placed into the resource table. */
>  static bool pci_mmcfg_running_state;
>  static bool pci_mmcfg_arch_init_failed;
> -static DEFINE_MUTEX(pci_mmcfg_lock);
> -
> -LIST_HEAD(pci_mmcfg_list);
> -
> -static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
> -{
> -	if (cfg->res.parent)
> -		release_resource(&cfg->res);
> -	list_del(&cfg->list);
> -	kfree(cfg);
> -}
> -
> -static void __init free_all_mmcfg(void)
> -{
> -	struct pci_mmcfg_region *cfg, *tmp;
> -
> -	pci_mmcfg_arch_free();
> -	list_for_each_entry_safe(cfg, tmp, &pci_mmcfg_list, list)
> -		pci_mmconfig_remove(cfg);
> -}
> -
> -static void list_add_sorted(struct pci_mmcfg_region *new)
> -{
> -	struct pci_mmcfg_region *cfg;
> -
> -	/* keep list sorted by segment and starting bus number */
> -	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
> -		if (cfg->segment > new->segment ||
> -		    (cfg->segment == new->segment &&
> -		     cfg->start_bus >= new->start_bus)) {
> -			list_add_tail_rcu(&new->list, &cfg->list);
> -			return;
> -		}
> -	}
> -	list_add_tail_rcu(&new->list, &pci_mmcfg_list);
> -}
> -
> -static struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
> -						   int end, u64 addr)
> -{
> -	struct pci_mmcfg_region *new;
> -	struct resource *res;
> -
> -	if (addr == 0)
> -		return NULL;
> -
> -	new = kzalloc(sizeof(*new), GFP_KERNEL);
> -	if (!new)
> -		return NULL;
> -
> -	new->address = addr;
> -	new->segment = segment;
> -	new->start_bus = start;
> -	new->end_bus = end;
> -
> -	res = &new->res;
> -	res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
> -	res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
> -	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> -	snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
> -		 "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
> -	res->name = new->name;
> -
> -	return new;
> -}
> -
> -static struct pci_mmcfg_region *__init pci_mmconfig_add(int segment, int start,
> -							int end, u64 addr)
> -{
> -	struct pci_mmcfg_region *new;
> -
> -	new = pci_mmconfig_alloc(segment, start, end, addr);
> -	if (new) {
> -		mutex_lock(&pci_mmcfg_lock);
> -		list_add_sorted(new);
> -		mutex_unlock(&pci_mmcfg_lock);
> -
> -		pr_info(PREFIX
> -		       "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
> -		       "(base %#lx)\n",
> -		       segment, start, end, &new->res, (unsigned long)addr);
> -	}
> -
> -	return new;
> -}
> -
> -struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
> -{
> -	struct pci_mmcfg_region *cfg;
> -
> -	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> -		if (cfg->segment == segment &&
> -		    cfg->start_bus <= bus && bus <= cfg->end_bus)
> -			return cfg;
> -
> -	return NULL;
> -}
>  
>  static const char *__init pci_mmcfg_e7520(void)
>  {
> @@ -543,7 +447,7 @@ static void __init pci_mmcfg_reject_broken(int early)
>  	}
>  }
>  
> -static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
> +int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
>  					struct acpi_mcfg_allocation *cfg)
>  {
>  	int year;
> @@ -566,50 +470,6 @@ static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
>  	return -EINVAL;
>  }
>  
> -static int __init pci_parse_mcfg(struct acpi_table_header *header)
> -{
> -	struct acpi_table_mcfg *mcfg;
> -	struct acpi_mcfg_allocation *cfg_table, *cfg;
> -	unsigned long i;
> -	int entries;
> -
> -	if (!header)
> -		return -EINVAL;
> -
> -	mcfg = (struct acpi_table_mcfg *)header;
> -
> -	/* how many config structures do we have */
> -	free_all_mmcfg();
> -	entries = 0;
> -	i = header->length - sizeof(struct acpi_table_mcfg);
> -	while (i >= sizeof(struct acpi_mcfg_allocation)) {
> -		entries++;
> -		i -= sizeof(struct acpi_mcfg_allocation);
> -	}
> -	if (entries == 0) {
> -		pr_err(PREFIX "MMCONFIG has no entries\n");
> -		return -ENODEV;
> -	}
> -
> -	cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
> -	for (i = 0; i < entries; i++) {
> -		cfg = &cfg_table[i];
> -		if (acpi_mcfg_check_entry(mcfg, cfg)) {
> -			free_all_mmcfg();
> -			return -ENODEV;
> -		}
> -
> -		if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
> -				   cfg->end_bus_number, cfg->address) == NULL) {
> -			pr_warn(PREFIX "no memory for MCFG entries\n");
> -			free_all_mmcfg();
> -			return -ENOMEM;
> -		}
> -	}
> -
> -	return 0;
> -}
> -
>  static void __init __pci_mmcfg_init(int early)
>  {
>  	pci_mmcfg_reject_broken(early);
> @@ -692,39 +552,6 @@ static int __init pci_mmcfg_late_insert_resources(void)
>   */
>  late_initcall(pci_mmcfg_late_insert_resources);
>  
> -static int __init pci_mmconfig_inject(struct pci_mmcfg_region *cfg)
> -{
> -	struct pci_mmcfg_region *cfg_conflict;
> -	int err = 0;
> -
> -	mutex_lock(&pci_mmcfg_lock);
> -	cfg_conflict = pci_mmconfig_lookup(cfg->segment, cfg->start_bus);
> -	if (cfg_conflict) {
> -		if (cfg_conflict->end_bus < cfg->end_bus)
> -			pr_info(FW_INFO "MMCONFIG for "
> -				"domain %04x [bus %02x-%02x] "
> -				"only partially covers this bridge\n",
> -				cfg_conflict->segment, cfg_conflict->start_bus,
> -				cfg_conflict->end_bus);
> -		err = -EEXIST;
> -		goto out;
> -	}
> -
> -	if (pci_mmcfg_arch_map(cfg)) {
> -		pr_warn("fail to map MMCONFIG %pR.\n", &cfg->res);
> -		err = -ENOMEM;
> -		goto out;
> -	} else {
> -		list_add_sorted(cfg);
> -		pr_info("MMCONFIG at %pR (base %#lx)\n",
> -			&cfg->res, (unsigned long)cfg->address);
> -
> -	}
> -out:
> -	mutex_unlock(&pci_mmcfg_lock);
> -	return err;
> -}
> -
>  /* Add MMCFG information for host bridges */
>  int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
>  			phys_addr_t addr)
> @@ -773,26 +600,3 @@ error:
>  	kfree(cfg);
>  	return rc;
>  }
> -
> -/* Delete MMCFG information for host bridges */
> -int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
> -{
> -	struct pci_mmcfg_region *cfg;
> -
> -	mutex_lock(&pci_mmcfg_lock);
> -	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> -		if (cfg->segment == seg && cfg->start_bus == start &&
> -		    cfg->end_bus == end) {
> -			list_del_rcu(&cfg->list);
> -			synchronize_rcu();
> -			pci_mmcfg_arch_unmap(cfg);
> -			if (cfg->res.parent)
> -				release_resource(&cfg->res);
> -			mutex_unlock(&pci_mmcfg_lock);
> -			kfree(cfg);
> -			return 0;
> -		}
> -	mutex_unlock(&pci_mmcfg_lock);
> -
> -	return -ENOENT;
> -}
> diff --git a/arch/x86/pci/mmconfig_32.c b/arch/x86/pci/mmconfig_32.c
> index 43984bc..d774672 100644
> --- a/arch/x86/pci/mmconfig_32.c
> +++ b/arch/x86/pci/mmconfig_32.c
> @@ -12,6 +12,7 @@
>  #include <linux/pci.h>
>  #include <linux/init.h>
>  #include <linux/rcupdate.h>
> +#include <linux/mmconfig.h>
>  #include <asm/e820.h>
>  #include <asm/pci_x86.h>
>  
> diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c
> index bea5249..1209596 100644
> --- a/arch/x86/pci/mmconfig_64.c
> +++ b/arch/x86/pci/mmconfig_64.c
> @@ -10,6 +10,7 @@
>  #include <linux/acpi.h>
>  #include <linux/bitmap.h>
>  #include <linux/rcupdate.h>
> +#include <linux/mmconfig.h>
>  #include <asm/e820.h>
>  #include <asm/pci_x86.h>
>  
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index c8a16e1..debacb5 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -69,6 +69,7 @@ obj-$(CONFIG_ACPI_BUTTON)	+= button.o
>  obj-$(CONFIG_ACPI_FAN)		+= fan.o
>  obj-$(CONFIG_ACPI_VIDEO)	+= video.o
>  obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
> +obj-$(CONFIG_PCI_MMCONFIG)	+= mmconfig.o
>  obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
>  obj-y				+= container.o
>  obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index c412fdb..6d5412ab 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -41,6 +41,7 @@
>  #include <acpi/apei.h>
>  #include <linux/dmi.h>
>  #include <linux/suspend.h>
> +#include <linux/mmconfig.h>
>  
>  #include "internal.h"
>  
> diff --git a/drivers/acpi/mmconfig.c b/drivers/acpi/mmconfig.c
> new file mode 100644
> index 0000000..d62dccda
> --- /dev/null
> +++ b/drivers/acpi/mmconfig.c
> @@ -0,0 +1,242 @@
> +/*
> + * Arch agnostic low-level direct PCI config space access via MMCONFIG
> + *
> + * Per-architecture code takes care of the mappings, region validation and
> + * accesses themselves.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/mutex.h>
> +#include <linux/rculist.h>
> +#include <linux/mmconfig.h>
> +
> +#define PREFIX "PCI: "
> +
> +static DEFINE_MUTEX(pci_mmcfg_lock);
> +
> +LIST_HEAD(pci_mmcfg_list);
> +
> +static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
> +{
> +	if (cfg->res.parent)
> +		release_resource(&cfg->res);
> +	list_del(&cfg->list);
> +	kfree(cfg);
> +}
> +
> +void __init free_all_mmcfg(void)
> +{
> +	struct pci_mmcfg_region *cfg, *tmp;
> +
> +	pci_mmcfg_arch_free();
> +	list_for_each_entry_safe(cfg, tmp, &pci_mmcfg_list, list)
> +		pci_mmconfig_remove(cfg);
> +}
> +
> +void list_add_sorted(struct pci_mmcfg_region *new)
> +{
> +	struct pci_mmcfg_region *cfg;
> +
> +	/* keep list sorted by segment and starting bus number */
> +	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
> +		if (cfg->segment > new->segment ||
> +		    (cfg->segment == new->segment &&
> +		     cfg->start_bus >= new->start_bus)) {
> +			list_add_tail_rcu(&new->list, &cfg->list);
> +			return;
> +		}
> +	}
> +	list_add_tail_rcu(&new->list, &pci_mmcfg_list);
> +}
> +
> +struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
> +					    int end, u64 addr)
> +{
> +	struct pci_mmcfg_region *new;
> +	struct resource *res;
> +
> +	if (addr == 0)
> +		return NULL;
> +
> +	new = kzalloc(sizeof(*new), GFP_KERNEL);
> +	if (!new)
> +		return NULL;
> +
> +	new->address = addr;
> +	new->segment = segment;
> +	new->start_bus = start;
> +	new->end_bus = end;
> +
> +	res = &new->res;
> +	res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
> +	res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
> +	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> +	snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
> +		 "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
> +	res->name = new->name;
> +
> +	return new;
> +}
> +
> +struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
> +					  int end, u64 addr)
> +{
> +	struct pci_mmcfg_region *new;
> +
> +	new = pci_mmconfig_alloc(segment, start, end, addr);
> +	if (new) {
> +		mutex_lock(&pci_mmcfg_lock);
> +		list_add_sorted(new);
> +		mutex_unlock(&pci_mmcfg_lock);
> +
> +		pr_info(PREFIX
> +		       "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
> +		       "(base %#lx)\n",
> +		       segment, start, end, &new->res, (unsigned long)addr);
> +	}
> +
> +	return new;
> +}
> +
> +int __init pci_mmconfig_inject(struct pci_mmcfg_region *cfg)
> +{
> +	struct pci_mmcfg_region *cfg_conflict;
> +	int err = 0;
> +
> +	mutex_lock(&pci_mmcfg_lock);
> +	cfg_conflict = pci_mmconfig_lookup(cfg->segment, cfg->start_bus);
> +	if (cfg_conflict) {
> +		if (cfg_conflict->end_bus < cfg->end_bus)
> +			pr_info(FW_INFO "MMCONFIG for "
> +				"domain %04x [bus %02x-%02x] "
> +				"only partially covers this bridge\n",
> +				cfg_conflict->segment, cfg_conflict->start_bus,
> +				cfg_conflict->end_bus);
> +		err = -EEXIST;
> +		goto out;
> +	}
> +
> +	if (pci_mmcfg_arch_map(cfg)) {
> +		pr_warn("fail to map MMCONFIG %pR.\n", &cfg->res);
> +		err = -ENOMEM;
> +		goto out;
> +	} else {
> +		list_add_sorted(cfg);
> +		pr_info("MMCONFIG at %pR (base %#lx)\n",
> +			&cfg->res, (unsigned long)cfg->address);
> +
> +	}
> +out:
> +	mutex_unlock(&pci_mmcfg_lock);
> +	return err;
> +}
> +
> +struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
> +{
> +	struct pci_mmcfg_region *cfg;
> +
> +	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> +		if (cfg->segment == segment &&
> +		    cfg->start_bus <= bus && bus <= cfg->end_bus)
> +			return cfg;
> +
> +	return NULL;
> +}
> +
> +int __init __weak acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
> +					struct acpi_mcfg_allocation *cfg)
> +{
> +	return 0;
> +}
> +
> +int __init pci_parse_mcfg(struct acpi_table_header *header)
> +{
> +	struct acpi_table_mcfg *mcfg;
> +	struct acpi_mcfg_allocation *cfg_table, *cfg;
> +	unsigned long i;
> +	int entries;
> +
> +	if (!header)
> +		return -EINVAL;
> +
> +	mcfg = (struct acpi_table_mcfg *)header;
> +
> +	/* how many config structures do we have */
> +	free_all_mmcfg();
> +	entries = 0;
> +	i = header->length - sizeof(struct acpi_table_mcfg);
> +	while (i >= sizeof(struct acpi_mcfg_allocation)) {
> +		entries++;
> +		i -= sizeof(struct acpi_mcfg_allocation);
> +	}
> +	if (entries == 0) {
> +		pr_err(PREFIX "MMCONFIG has no entries\n");
> +		return -ENODEV;
> +	}
> +
> +	cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
> +	for (i = 0; i < entries; i++) {
> +		cfg = &cfg_table[i];
> +		if (acpi_mcfg_check_entry(mcfg, cfg)) {
> +			free_all_mmcfg();
> +			return -ENODEV;
> +		}
> +
> +		if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
> +				   cfg->end_bus_number, cfg->address) == NULL) {
> +			pr_warn(PREFIX "no memory for MCFG entries\n");
> +			free_all_mmcfg();
> +			return -ENOMEM;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/* Delete MMCFG information for host bridges */
> +int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
> +{
> +	struct pci_mmcfg_region *cfg;
> +
> +	mutex_lock(&pci_mmcfg_lock);
> +	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> +		if (cfg->segment == seg && cfg->start_bus == start &&
> +		    cfg->end_bus == end) {
> +			list_del_rcu(&cfg->list);
> +			synchronize_rcu();
> +			pci_mmcfg_arch_unmap(cfg);
> +			if (cfg->res.parent)
> +				release_resource(&cfg->res);
> +			mutex_unlock(&pci_mmcfg_lock);
> +			kfree(cfg);
> +			return 0;
> +		}
> +	mutex_unlock(&pci_mmcfg_lock);
> +
> +	return -ENOENT;
> +}
> +
> +void __init __weak pci_mmcfg_early_init(void)
> +{
> +
> +}
> +
> +void __init __weak pci_mmcfg_late_init(void)
> +{
> +	struct pci_mmcfg_region *cfg;
> +
> +	acpi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
> +
> +	if (list_empty(&pci_mmcfg_list))
> +		return;
> +
> +	if (!pci_mmcfg_arch_init())
> +		free_all_mmcfg();
> +
> +	list_for_each_entry(cfg, &pci_mmcfg_list, list)
> +		insert_resource(&iomem_resource, &cfg->res);
> +}
> diff --git a/include/linux/mmconfig.h b/include/linux/mmconfig.h
> new file mode 100644
> index 0000000..6ccd1ee
> --- /dev/null
> +++ b/include/linux/mmconfig.h
> @@ -0,0 +1,58 @@
> +#ifndef __MMCONFIG_H
> +#define __MMCONFIG_H
> +#ifdef __KERNEL__
> +
> +#include <linux/types.h>
> +#include <linux/acpi.h>
> +
> +#ifdef CONFIG_PCI_MMCONFIG
> +/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
> +#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
> +
> +struct pci_mmcfg_region {
> +	struct list_head list;
> +	struct resource res;
> +	u64 address;
> +	char __iomem *virt;
> +	u16 segment;
> +	u8 start_bus;
> +	u8 end_bus;
> +	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
> +};
> +
> +void pci_mmcfg_early_init(void);
> +void pci_mmcfg_late_init(void);
> +struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
> +
> +int pci_parse_mcfg(struct acpi_table_header *header);
> +struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
> +						   int end, u64 addr);
> +int pci_mmconfig_inject(struct pci_mmcfg_region *cfg);
> +struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
> +						 int end, u64 addr);
> +void list_add_sorted(struct pci_mmcfg_region *new);
> +int acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
> +			  struct acpi_mcfg_allocation *cfg);
> +void free_all_mmcfg(void);
> +int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
> +		       phys_addr_t addr);
> +int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
> +
> +/* Arch specific calls */
> +int pci_mmcfg_arch_init(void);
> +void pci_mmcfg_arch_free(void);
> +int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg);
> +void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg);
> +
> +extern struct list_head pci_mmcfg_list;
> +
> +#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
> +#else /* CONFIG_PCI_MMCONFIG */
> +static inline void pci_mmcfg_late_init(void) { }
> +static inline void pci_mmcfg_early_init(void) { }
> +static inline void *pci_mmconfig_lookup(int segment, int bus)
> +{ return NULL; }
> +#endif /* CONFIG_PCI_MMCONFIG */
> +
> +#endif  /* __KERNEL__ */
> +#endif  /* __MMCONFIG_H */
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 6afba72..0a8b82e 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1658,14 +1658,6 @@ void pcibios_release_device(struct pci_dev *dev);
>  extern struct dev_pm_ops pcibios_pm_ops;
>  #endif
>  
> -#ifdef CONFIG_PCI_MMCONFIG
> -void __init pci_mmcfg_early_init(void);
> -void __init pci_mmcfg_late_init(void);
> -#else
> -static inline void pci_mmcfg_early_init(void) { }
> -static inline void pci_mmcfg_late_init(void) { }
> -#endif
> -
>  int pci_ext_cfg_avail(void);
>  
>  void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar);
> -- 
> 1.9.1
>