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linux-xiaomi-chiron/include/linux/ioport.h
David Hildenbrand 7b7b27214b mm/memory_hotplug: introduce add_memory_driver_managed() 
Patch series "mm/memory_hotplug: Interface to add driver-managed system
ram", v4.

kexec (via kexec_load()) can currently not properly handle memory added
via dax/kmem, and will have similar issues with virtio-mem.  kexec-tools
will currently add all memory to the fixed-up initial firmware memmap.  In
case of dax/kmem, this means that - in contrast to a proper reboot - how
that persistent memory will be used can no longer be configured by the
kexec'd kernel.  In case of virtio-mem it will be harmful, because that
memory might contain inaccessible pieces that require coordination with
hypervisor first.

In both cases, we want to let the driver in the kexec'd kernel handle
detecting and adding the memory, like during an ordinary reboot.
Introduce add_memory_driver_managed().  More on the samentics are in patch
#1.

In the future, we might want to make this behavior configurable for
dax/kmem- either by configuring it in the kernel (which would then also
allow to configure kexec_file_load()) or in kexec-tools by also adding
"System RAM (kmem)" memory from /proc/iomem to the fixed-up initial
firmware memmap.

More on the motivation can be found in [1] and [2].

[1] https://lkml.kernel.org/r/20200429160803.109056-1-david@redhat.com
[2] https://lkml.kernel.org/r/20200430102908.10107-1-david@redhat.com

This patch (of 3):

Some device drivers rely on memory they managed to not get added to the
initial (firmware) memmap as system RAM - so it's not used as initial
system RAM by the kernel and the driver is under control.  While this is
the case during cold boot and after a reboot, kexec is not aware of that
and might add such memory to the initial (firmware) memmap of the kexec
kernel.  We need ways to teach kernel and userspace that this system ram
is different.

For example, dax/kmem allows to decide at runtime if persistent memory is
to be used as system ram.  Another future user is virtio-mem, which has to
coordinate with its hypervisor to deal with inaccessible parts within
memory resources.

We want to let users in the kernel (esp. kexec) but also user space
(esp. kexec-tools) know that this memory has different semantics and
needs to be handled differently:
1. Don't create entries in /sys/firmware/memmap/
2. Name the memory resource "System RAM ($DRIVER)" (exposed via
   /proc/iomem) ($DRIVER might be "kmem", "virtio_mem").
3. Flag the memory resource IORESOURCE_MEM_DRIVER_MANAGED

/sys/firmware/memmap/ [1] represents the "raw firmware-provided memory
map" because "on most architectures that firmware-provided memory map is
modified afterwards by the kernel itself".  The primary user is kexec on
x86-64.  Since commit d96ae53091 ("memory-hotplug: create
/sys/firmware/memmap entry for new memory"), we add all hotplugged memory
to that firmware memmap - which makes perfect sense for traditional memory
hotplug on x86-64, where real HW will also add hotplugged DIMMs to the
firmware memmap.  We replicate what the "raw firmware-provided memory map"
looks like after hot(un)plug.

To keep things simple, let the user provide the full resource name instead
of only the driver name - this way, we don't have to manually
allocate/craft strings for memory resources.  Also use the resource name
to make decisions, to avoid passing additional flags.  In case the name
isn't "System RAM", it's special.

We don't have to worry about firmware_map_remove() on the removal path.
If there is no entry, it will simply return with -EINVAL.

We'll adapt dax/kmem in a follow-up patch.

[1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-firmware-memmap

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Link: http://lkml.kernel.org/r/20200508084217.9160-1-david@redhat.com
Link: http://lkml.kernel.org/r/20200508084217.9160-3-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04 19:06:23 -07:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* ioport.h Definitions of routines for detecting, reserving and
* allocating system resources.
*
* Authors: Linus Torvalds
*/
#ifndef _LINUX_IOPORT_H
#define _LINUX_IOPORT_H
#ifndef __ASSEMBLY__
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/bits.h>
/*
* Resources are tree-like, allowing
* nesting etc..
*/
struct resource {
resource_size_t start;
resource_size_t end;
const char *name;
unsigned long flags;
unsigned long desc;
struct resource *parent, *sibling, *child;
};
/*
* IO resources have these defined flags.
*
* PCI devices expose these flags to userspace in the "resource" sysfs file,
* so don't move them.
*/
#define IORESOURCE_BITS 0x000000ff /* Bus-specific bits */
#define IORESOURCE_TYPE_BITS 0x00001f00 /* Resource type */
#define IORESOURCE_IO 0x00000100 /* PCI/ISA I/O ports */
#define IORESOURCE_MEM 0x00000200
#define IORESOURCE_REG 0x00000300 /* Register offsets */
#define IORESOURCE_IRQ 0x00000400
#define IORESOURCE_DMA 0x00000800
#define IORESOURCE_BUS 0x00001000
#define IORESOURCE_PREFETCH 0x00002000 /* No side effects */
#define IORESOURCE_READONLY 0x00004000
#define IORESOURCE_CACHEABLE 0x00008000
#define IORESOURCE_RANGELENGTH 0x00010000
#define IORESOURCE_SHADOWABLE 0x00020000
#define IORESOURCE_SIZEALIGN 0x00040000 /* size indicates alignment */
#define IORESOURCE_STARTALIGN 0x00080000 /* start field is alignment */
#define IORESOURCE_MEM_64 0x00100000
#define IORESOURCE_WINDOW 0x00200000 /* forwarded by bridge */
#define IORESOURCE_MUXED 0x00400000 /* Resource is software muxed */
#define IORESOURCE_EXT_TYPE_BITS 0x01000000 /* Resource extended types */
#define IORESOURCE_SYSRAM 0x01000000 /* System RAM (modifier) */
#define IORESOURCE_EXCLUSIVE 0x08000000 /* Userland may not map this resource */
#define IORESOURCE_DISABLED 0x10000000
#define IORESOURCE_UNSET 0x20000000 /* No address assigned yet */
#define IORESOURCE_AUTO 0x40000000
#define IORESOURCE_BUSY 0x80000000 /* Driver has marked this resource busy */
/* I/O resource extended types */
#define IORESOURCE_SYSTEM_RAM (IORESOURCE_MEM|IORESOURCE_SYSRAM)
/* PnP IRQ specific bits (IORESOURCE_BITS) */
#define IORESOURCE_IRQ_HIGHEDGE (1<<0)
#define IORESOURCE_IRQ_LOWEDGE (1<<1)
#define IORESOURCE_IRQ_HIGHLEVEL (1<<2)
#define IORESOURCE_IRQ_LOWLEVEL (1<<3)
#define IORESOURCE_IRQ_SHAREABLE (1<<4)
#define IORESOURCE_IRQ_OPTIONAL (1<<5)
/* PnP DMA specific bits (IORESOURCE_BITS) */
#define IORESOURCE_DMA_TYPE_MASK (3<<0)
#define IORESOURCE_DMA_8BIT (0<<0)
#define IORESOURCE_DMA_8AND16BIT (1<<0)
#define IORESOURCE_DMA_16BIT (2<<0)
#define IORESOURCE_DMA_MASTER (1<<2)
#define IORESOURCE_DMA_BYTE (1<<3)
#define IORESOURCE_DMA_WORD (1<<4)
#define IORESOURCE_DMA_SPEED_MASK (3<<6)
#define IORESOURCE_DMA_COMPATIBLE (0<<6)
#define IORESOURCE_DMA_TYPEA (1<<6)
#define IORESOURCE_DMA_TYPEB (2<<6)
#define IORESOURCE_DMA_TYPEF (3<<6)
/* PnP memory I/O specific bits (IORESOURCE_BITS) */
#define IORESOURCE_MEM_WRITEABLE (1<<0) /* dup: IORESOURCE_READONLY */
#define IORESOURCE_MEM_CACHEABLE (1<<1) /* dup: IORESOURCE_CACHEABLE */
#define IORESOURCE_MEM_RANGELENGTH (1<<2) /* dup: IORESOURCE_RANGELENGTH */
#define IORESOURCE_MEM_TYPE_MASK (3<<3)
#define IORESOURCE_MEM_8BIT (0<<3)
#define IORESOURCE_MEM_16BIT (1<<3)
#define IORESOURCE_MEM_8AND16BIT (2<<3)
#define IORESOURCE_MEM_32BIT (3<<3)
#define IORESOURCE_MEM_SHADOWABLE (1<<5) /* dup: IORESOURCE_SHADOWABLE */
#define IORESOURCE_MEM_EXPANSIONROM (1<<6)
#define IORESOURCE_MEM_DRIVER_MANAGED (1<<7)
/* PnP I/O specific bits (IORESOURCE_BITS) */
#define IORESOURCE_IO_16BIT_ADDR (1<<0)
#define IORESOURCE_IO_FIXED (1<<1)
#define IORESOURCE_IO_SPARSE (1<<2)
/* PCI ROM control bits (IORESOURCE_BITS) */
#define IORESOURCE_ROM_ENABLE (1<<0) /* ROM is enabled, same as PCI_ROM_ADDRESS_ENABLE */
#define IORESOURCE_ROM_SHADOW (1<<1) /* Use RAM image, not ROM BAR */
/* PCI control bits. Shares IORESOURCE_BITS with above PCI ROM. */
#define IORESOURCE_PCI_FIXED (1<<4) /* Do not move resource */
#define IORESOURCE_PCI_EA_BEI (1<<5) /* BAR Equivalent Indicator */
/*
* I/O Resource Descriptors
*
* Descriptors are used by walk_iomem_res_desc() and region_intersects()
* for searching a specific resource range in the iomem table. Assign
* a new descriptor when a resource range supports the search interfaces.
* Otherwise, resource.desc must be set to IORES_DESC_NONE (0).
*/
enum {
IORES_DESC_NONE = 0,
IORES_DESC_CRASH_KERNEL = 1,
IORES_DESC_ACPI_TABLES = 2,
IORES_DESC_ACPI_NV_STORAGE = 3,
IORES_DESC_PERSISTENT_MEMORY = 4,
IORES_DESC_PERSISTENT_MEMORY_LEGACY = 5,
IORES_DESC_DEVICE_PRIVATE_MEMORY = 6,
IORES_DESC_RESERVED = 7,
IORES_DESC_SOFT_RESERVED = 8,
};
/*
* Flags controlling ioremap() behavior.
*/
enum {
IORES_MAP_SYSTEM_RAM = BIT(0),
IORES_MAP_ENCRYPTED = BIT(1),
};
/* helpers to define resources */
#define DEFINE_RES_NAMED(_start, _size, _name, _flags) \
{ \
.start = (_start), \
.end = (_start) + (_size) - 1, \
.name = (_name), \
.flags = (_flags), \
.desc = IORES_DESC_NONE, \
}
#define DEFINE_RES_IO_NAMED(_start, _size, _name) \
DEFINE_RES_NAMED((_start), (_size), (_name), IORESOURCE_IO)
#define DEFINE_RES_IO(_start, _size) \
DEFINE_RES_IO_NAMED((_start), (_size), NULL)
#define DEFINE_RES_MEM_NAMED(_start, _size, _name) \
DEFINE_RES_NAMED((_start), (_size), (_name), IORESOURCE_MEM)
#define DEFINE_RES_MEM(_start, _size) \
DEFINE_RES_MEM_NAMED((_start), (_size), NULL)
#define DEFINE_RES_IRQ_NAMED(_irq, _name) \
DEFINE_RES_NAMED((_irq), 1, (_name), IORESOURCE_IRQ)
#define DEFINE_RES_IRQ(_irq) \
DEFINE_RES_IRQ_NAMED((_irq), NULL)
#define DEFINE_RES_DMA_NAMED(_dma, _name) \
DEFINE_RES_NAMED((_dma), 1, (_name), IORESOURCE_DMA)
#define DEFINE_RES_DMA(_dma) \
DEFINE_RES_DMA_NAMED((_dma), NULL)
/* PC/ISA/whatever - the normal PC address spaces: IO and memory */
extern struct resource ioport_resource;
extern struct resource iomem_resource;
extern struct resource *request_resource_conflict(struct resource *root, struct resource *new);
extern int request_resource(struct resource *root, struct resource *new);
extern int release_resource(struct resource *new);
void release_child_resources(struct resource *new);
extern void reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
const char *name);
extern struct resource *insert_resource_conflict(struct resource *parent, struct resource *new);
extern int insert_resource(struct resource *parent, struct resource *new);
extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);
extern int remove_resource(struct resource *old);
extern void arch_remove_reservations(struct resource *avail);
extern int allocate_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,
resource_size_t (*alignf)(void *,
const struct resource *,
resource_size_t,
resource_size_t),
void *alignf_data);
struct resource *lookup_resource(struct resource *root, resource_size_t start);
int adjust_resource(struct resource *res, resource_size_t start,
resource_size_t size);
resource_size_t resource_alignment(struct resource *res);
static inline resource_size_t resource_size(const struct resource *res)
{
return res->end - res->start + 1;
}
static inline unsigned long resource_type(const struct resource *res)
{
return res->flags & IORESOURCE_TYPE_BITS;
}
static inline unsigned long resource_ext_type(const struct resource *res)
{
return res->flags & IORESOURCE_EXT_TYPE_BITS;
}
/* True iff r1 completely contains r2 */
static inline bool resource_contains(struct resource *r1, struct resource *r2)
{
if (resource_type(r1) != resource_type(r2))
return false;
if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET)
return false;
return r1->start <= r2->start && r1->end >= r2->end;
}
/* Convenience shorthand with allocation */
#define request_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name), 0)
#define request_muxed_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name), IORESOURCE_MUXED)
#define __request_mem_region(start,n,name, excl) __request_region(&iomem_resource, (start), (n), (name), excl)
#define request_mem_region(start,n,name) __request_region(&iomem_resource, (start), (n), (name), 0)
#define request_mem_region_exclusive(start,n,name) \
__request_region(&iomem_resource, (start), (n), (name), IORESOURCE_EXCLUSIVE)
#define rename_region(region, newname) do { (region)->name = (newname); } while (0)
extern struct resource * __request_region(struct resource *,
resource_size_t start,
resource_size_t n,
const char *name, int flags);
/* Compatibility cruft */
#define release_region(start,n) __release_region(&ioport_resource, (start), (n))
#define release_mem_region(start,n) __release_region(&iomem_resource, (start), (n))
extern void __release_region(struct resource *, resource_size_t,
resource_size_t);
#ifdef CONFIG_MEMORY_HOTREMOVE
extern int release_mem_region_adjustable(struct resource *, resource_size_t,
resource_size_t);
#endif
/* Wrappers for managed devices */
struct device;
extern int devm_request_resource(struct device *dev, struct resource *root,
struct resource *new);
extern void devm_release_resource(struct device *dev, struct resource *new);
#define devm_request_region(dev,start,n,name) \
__devm_request_region(dev, &ioport_resource, (start), (n), (name))
#define devm_request_mem_region(dev,start,n,name) \
__devm_request_region(dev, &iomem_resource, (start), (n), (name))
extern struct resource * __devm_request_region(struct device *dev,
struct resource *parent, resource_size_t start,
resource_size_t n, const char *name);
#define devm_release_region(dev, start, n) \
__devm_release_region(dev, &ioport_resource, (start), (n))
#define devm_release_mem_region(dev, start, n) \
__devm_release_region(dev, &iomem_resource, (start), (n))
extern void __devm_release_region(struct device *dev, struct resource *parent,
resource_size_t start, resource_size_t n);
extern int iomem_map_sanity_check(resource_size_t addr, unsigned long size);
extern bool iomem_is_exclusive(u64 addr);
extern int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg, int (*func)(unsigned long, unsigned long, void *));
extern int
walk_mem_res(u64 start, u64 end, void *arg,
int (*func)(struct resource *, void *));
extern int
walk_system_ram_res(u64 start, u64 end, void *arg,
int (*func)(struct resource *, void *));
extern int
walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end,
void *arg, int (*func)(struct resource *, void *));
/* True if any part of r1 overlaps r2 */
static inline bool resource_overlaps(struct resource *r1, struct resource *r2)
{
return (r1->start <= r2->end && r1->end >= r2->start);
}
struct resource *devm_request_free_mem_region(struct device *dev,
struct resource *base, unsigned long size);
struct resource *request_free_mem_region(struct resource *base,
unsigned long size, const char *name);
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_IOPORT_H */
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