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Merge tag 'driver-core-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Browse Source 
Pull driver core updates from Greg KH:
 "Just a few patches this time around for the 4.6-rc1 merge window.
  Largest is a new firmware driver, but there are some other updates to
  the driver core in here as well, the shortlog has the details.

  All have been in linux-next for a while with no reported issues"

* tag 'driver-core-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  Revert "driver-core: platform: probe of-devices only using list of compatibles"
  firmware: qemu config needs I/O ports
  firmware: qemu_fw_cfg.c: fix typo FW_CFG_DATA_OFF
  driver-core: platform: probe of-devices only using list of compatibles
  driver-core: platform: fix typo in documentation for multi-driver helper
  component: remove impossible condition
  drivers: dma-coherent: simplify dma_init_coherent_memory return value
  devicetree: update documentation for fw_cfg ARM bindings
  firmware: create directory hierarchy for sysfs fw_cfg entries
  firmware: introduce sysfs driver for QEMU's fw_cfg device
  kobject: export kset_find_obj() for module use
  driver core: bus: use to_subsys_private and to_device_private_bus
  driver core: bus: use list_for_each_entry*
  debugfs: Add stub function for debugfs_create_automount().
  kernfs: make kernfs_walk_ns() use kernfs_pr_cont_buf[]
This commit is contained in:
Linus Torvalds
2016-03-17 13:38:00 -07:00
parent 45cb5230f8 112d125a89
commit 1a4ab084af
12 changed files with 915 additions and 70 deletions
Download Patch File Download Diff File Expand all files Collapse all files

100
Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg Normal file
View File

@@ -0,0 +1,100 @@
What: /sys/firmware/qemu_fw_cfg/
Date: August 2015
Contact: Gabriel Somlo <somlo@cmu.edu>
Description:
Several different architectures supported by QEMU (x86, arm,
sun4*, ppc/mac) are provisioned with a firmware configuration
(fw_cfg) device, originally intended as a way for the host to
provide configuration data to the guest firmware. Starting
with QEMU v2.4, arbitrary fw_cfg file entries may be specified
by the user on the command line, which makes fw_cfg additionally
useful as an out-of-band, asynchronous mechanism for providing
configuration data to the guest userspace.
The authoritative guest-side hardware interface documentation
to the fw_cfg device can be found in "docs/specs/fw_cfg.txt"
in the QEMU source tree.
=== SysFS fw_cfg Interface ===
The fw_cfg sysfs interface described in this document is only
intended to display discoverable blobs (i.e., those registered
with the file directory), as there is no way to determine the
presence or size of "legacy" blobs (with selector keys between
0x0002 and 0x0018) programmatically.
All fw_cfg information is shown under:
/sys/firmware/qemu_fw_cfg/
The only legacy blob displayed is the fw_cfg device revision:
/sys/firmware/qemu_fw_cfg/rev
--- Discoverable fw_cfg blobs by selector key ---
All discoverable blobs listed in the fw_cfg file directory are
displayed as entries named after their unique selector key
value, e.g.:
/sys/firmware/qemu_fw_cfg/by_key/32
/sys/firmware/qemu_fw_cfg/by_key/33
/sys/firmware/qemu_fw_cfg/by_key/34
...
Each such fw_cfg sysfs entry has the following values exported
as attributes:
name : The 56-byte nul-terminated ASCII string used as the
blob's 'file name' in the fw_cfg directory.
size : The length of the blob, as given in the fw_cfg
directory.
key : The value of the blob's selector key as given in the
fw_cfg directory. This value is the same as used in
the parent directory name.
raw : The raw bytes of the blob, obtained by selecting the
entry via the control register, and reading a number
of bytes equal to the blob size from the data
register.
--- Listing fw_cfg blobs by file name ---
While the fw_cfg device does not impose any specific naming
convention on the blobs registered in the file directory,
QEMU developers have traditionally used path name semantics
to give each blob a descriptive name. For example:
"bootorder"
"genroms/kvmvapic.bin"
"etc/e820"
"etc/boot-fail-wait"
"etc/system-states"
"etc/table-loader"
"etc/acpi/rsdp"
"etc/acpi/tables"
"etc/smbios/smbios-tables"
"etc/smbios/smbios-anchor"
...
In addition to the listing by unique selector key described
above, the fw_cfg sysfs driver also attempts to build a tree
of directories matching the path name components of fw_cfg
blob names, ending in symlinks to the by_key entry for each
"basename", as illustrated below (assume current directory is
/sys/firmware):
qemu_fw_cfg/by_name/bootorder -> ../by_key/38
qemu_fw_cfg/by_name/etc/e820 -> ../../by_key/35
qemu_fw_cfg/by_name/etc/acpi/rsdp -> ../../../by_key/41
...
Construction of the directory tree and symlinks is done on a
"best-effort" basis, as there is no guarantee that components
of fw_cfg blob names are always "well behaved". I.e., there is
the possibility that a symlink (basename) will conflict with
a dirname component of another fw_cfg blob, in which case the
creation of the offending /sys/firmware/qemu_fw_cfg/by_name
entry will be skipped.
The authoritative list of entries will continue to be found
under the /sys/firmware/qemu_fw_cfg/by_key directory.

38
Documentation/devicetree/bindings/arm/fw-cfg.txt
View File

@@ -11,43 +11,9 @@ QEMU exposes the control and data register to ARM guests as memory mapped
registers; their location is communicated to the guest's UEFI firmware in the registers; their location is communicated to the guest's UEFI firmware in the
DTB that QEMU places at the bottom of the guest's DRAM. DTB that QEMU places at the bottom of the guest's DRAM.
The guest writes a selector value (a key) to the selector register, and then The authoritative guest-side hardware interface documentation to the fw_cfg
can read the corresponding data (produced by QEMU) via the data register. If device can be found in "docs/specs/fw_cfg.txt" in the QEMU source tree.
the selected entry is writable, the guest can rewrite it through the data
register.
The selector register takes keys in big endian byte order.
The data register allows accesses with 8, 16, 32 and 64-bit width (only at
offset 0 of the register). Accesses larger than a byte are interpreted as
arrays, bundled together only for better performance. The bytes constituting
such a word, in increasing address order, correspond to the bytes that would
have been transferred by byte-wide accesses in chronological order.
The interface allows guest firmware to download various parameters and blobs
that affect how the firmware works and what tables it installs for the guest
OS. For example, boot order of devices, ACPI tables, SMBIOS tables, kernel and
initrd images for direct kernel booting, virtual machine UUID, SMP information,
virtual NUMA topology, and so on.
The authoritative registry of the valid selector values and their meanings is
the QEMU source code; the structure of the data blobs corresponding to the
individual key values is also defined in the QEMU source code.
The presence of the registers can be verified by selecting the "signature" blob
with key 0x0000, and reading four bytes from the data register. The returned
signature is "QEMU".
The outermost protocol (involving the write / read sequences of the control and
data registers) is expected to be versioned, and/or described by feature bits.
The interface revision / feature bitmap can be retrieved with key 0x0001. The
blob to be read from the data register has size 4, and it is to be interpreted
as a uint32_t value in little endian byte order. The current value
(corresponding to the above outer protocol) is zero.
The guest kernel is not expected to use these registers (although it is
certainly allowed to); the device tree bindings are documented here because
this is where device tree bindings reside in general.
Required properties: Required properties:

2
Documentation/driver-model/platform.txt
View File

@@ -75,7 +75,7 @@ If one of the drivers fails to register, all drivers registered up to that
point will be unregistered in reverse order. Note that there is a convenience point will be unregistered in reverse order. Note that there is a convenience
macro that passes THIS_MODULE as owner parameter: macro that passes THIS_MODULE as owner parameter:
#define platform_register_driver(drivers, count) #define platform_register_drivers(drivers, count)
Device Enumeration Device Enumeration

15
drivers/base/bus.c
View File

@@ -149,8 +149,7 @@ EXPORT_SYMBOL_GPL(bus_remove_file);
static void bus_release(struct kobject *kobj) static void bus_release(struct kobject *kobj)
{ {
struct subsys_private *priv = struct subsys_private *priv = to_subsys_private(kobj);
container_of(kobj, typeof(*priv), subsys.kobj);
struct bus_type *bus = priv->bus; struct bus_type *bus = priv->bus;
kfree(priv); kfree(priv);
@@ -1019,13 +1018,11 @@ static void device_insertion_sort_klist(struct device *a, struct list_head *list
int (*compare)(const struct device *a, int (*compare)(const struct device *a,
const struct device *b)) const struct device *b))
{ {
struct list_head *pos;
struct klist_node *n; struct klist_node *n;
struct device_private *dev_prv; struct device_private *dev_prv;
struct device *b; struct device *b;
list_for_each(pos, list) { list_for_each_entry(n, list, n_node) {
n = container_of(pos, struct klist_node, n_node);
dev_prv = to_device_private_bus(n); dev_prv = to_device_private_bus(n);
b = dev_prv->device; b = dev_prv->device;
if (compare(a, b) <= 0) { if (compare(a, b) <= 0) {
@@ -1042,8 +1039,7 @@ void bus_sort_breadthfirst(struct bus_type *bus,
const struct device *b)) const struct device *b))
{ {
LIST_HEAD(sorted_devices); LIST_HEAD(sorted_devices);
struct list_head *pos, *tmp; struct klist_node *n, *tmp;
struct klist_node *n;
struct device_private *dev_prv; struct device_private *dev_prv;
struct device *dev; struct device *dev;
struct klist *device_klist; struct klist *device_klist;
@@ -1051,8 +1047,7 @@ void bus_sort_breadthfirst(struct bus_type *bus,
device_klist = bus_get_device_klist(bus); device_klist = bus_get_device_klist(bus);
spin_lock(&device_klist->k_lock); spin_lock(&device_klist->k_lock);
list_for_each_safe(pos, tmp, &device_klist->k_list) { list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) {
n = container_of(pos, struct klist_node, n_node);
dev_prv = to_device_private_bus(n); dev_prv = to_device_private_bus(n);
dev = dev_prv->device; dev = dev_prv->device;
device_insertion_sort_klist(dev, &sorted_devices, compare); device_insertion_sort_klist(dev, &sorted_devices, compare);
@@ -1107,7 +1102,7 @@ struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
knode = klist_next(&iter->ki); knode = klist_next(&iter->ki);
if (!knode) if (!knode)
return NULL; return NULL;
dev = container_of(knode, struct device_private, knode_bus)->device; dev = to_device_private_bus(knode)->device;
if (!iter->type || iter->type == dev->type) if (!iter->type || iter->type == dev->type)
return dev; return dev;
} }

2
drivers/base/component.c
View File

@@ -267,7 +267,7 @@ void component_match_add_release(struct device *master,
} }
if (match->num == match->alloc) { if (match->num == match->alloc) {
size_t new_size = match ? match->alloc + 16 : 15; size_t new_size = match->alloc + 16;
int ret; int ret;
ret = component_match_realloc(master, match, new_size); ret = component_match_realloc(master, match, new_size);

28
drivers/base/dma-coherent.c
View File

@@ -17,9 +17,9 @@ struct dma_coherent_mem {
spinlock_t spinlock; spinlock_t spinlock;
}; };
static int dma_init_coherent_memory(phys_addr_t phys_addr, dma_addr_t device_addr, static bool dma_init_coherent_memory(
size_t size, int flags, phys_addr_t phys_addr, dma_addr_t device_addr, size_t size, int flags,
struct dma_coherent_mem **mem) struct dma_coherent_mem **mem)
{ {
struct dma_coherent_mem *dma_mem = NULL; struct dma_coherent_mem *dma_mem = NULL;
void __iomem *mem_base = NULL; void __iomem *mem_base = NULL;
@@ -50,17 +50,13 @@ static int dma_init_coherent_memory(phys_addr_t phys_addr, dma_addr_t device_add
spin_lock_init(&dma_mem->spinlock); spin_lock_init(&dma_mem->spinlock);
*mem = dma_mem; *mem = dma_mem;
return true;
if (flags & DMA_MEMORY_MAP)
return DMA_MEMORY_MAP;
return DMA_MEMORY_IO;
out: out:
kfree(dma_mem); kfree(dma_mem);
if (mem_base) if (mem_base)
iounmap(mem_base); iounmap(mem_base);
return 0; return false;
} }
static void dma_release_coherent_memory(struct dma_coherent_mem *mem) static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
@@ -88,15 +84,13 @@ int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
dma_addr_t device_addr, size_t size, int flags) dma_addr_t device_addr, size_t size, int flags)
{ {
struct dma_coherent_mem *mem; struct dma_coherent_mem *mem;
int ret;
ret = dma_init_coherent_memory(phys_addr, device_addr, size, flags, if (!dma_init_coherent_memory(phys_addr, device_addr, size, flags,
&mem); &mem))
if (ret == 0)
return 0; return 0;
if (dma_assign_coherent_memory(dev, mem) == 0) if (dma_assign_coherent_memory(dev, mem) == 0)
return ret; return flags & DMA_MEMORY_MAP ? DMA_MEMORY_MAP : DMA_MEMORY_IO;
dma_release_coherent_memory(mem); dma_release_coherent_memory(mem);
return 0; return 0;
@@ -281,9 +275,9 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
struct dma_coherent_mem *mem = rmem->priv; struct dma_coherent_mem *mem = rmem->priv;
if (!mem && if (!mem &&
dma_init_coherent_memory(rmem->base, rmem->base, rmem->size, !dma_init_coherent_memory(rmem->base, rmem->base, rmem->size,
DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE, DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE,
&mem) != DMA_MEMORY_MAP) { &mem)) {
pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n", pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
&rmem->base, (unsigned long)rmem->size / SZ_1M); &rmem->base, (unsigned long)rmem->size / SZ_1M);
return -ENODEV; return -ENODEV;

20
drivers/firmware/Kconfig
View File

@@ -161,6 +161,26 @@ config RASPBERRYPI_FIRMWARE
This option enables support for communicating with the firmware on the This option enables support for communicating with the firmware on the
Raspberry Pi. Raspberry Pi.
config FW_CFG_SYSFS
tristate "QEMU fw_cfg device support in sysfs"
depends on SYSFS && (ARM || ARM64 || PPC_PMAC || SPARC || X86)
depends on HAS_IOPORT_MAP
default n
help
Say Y or M here to enable the exporting of the QEMU firmware
configuration (fw_cfg) file entries via sysfs. Entries are
found under /sys/firmware/fw_cfg when this option is enabled
and loaded.
config FW_CFG_SYSFS_CMDLINE
bool "QEMU fw_cfg device parameter parsing"
depends on FW_CFG_SYSFS
help
Allow the qemu_fw_cfg device to be initialized via the kernel
command line or using a module parameter.
WARNING: Using incorrect parameters (base address in particular)
may crash your system.
config QCOM_SCM config QCOM_SCM
bool bool
depends on ARM || ARM64 depends on ARM || ARM64

1
drivers/firmware/Makefile
View File

@@ -14,6 +14,7 @@ obj-$(CONFIG_ISCSI_IBFT_FIND) += iscsi_ibft_find.o
obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o
obj-$(CONFIG_QCOM_SCM) += qcom_scm.o obj-$(CONFIG_QCOM_SCM) += qcom_scm.o
obj-$(CONFIG_QCOM_SCM_64) += qcom_scm-64.o obj-$(CONFIG_QCOM_SCM_64) += qcom_scm-64.o
obj-$(CONFIG_QCOM_SCM_32) += qcom_scm-32.o obj-$(CONFIG_QCOM_SCM_32) += qcom_scm-32.o

751
drivers/firmware/qemu_fw_cfg.c Normal file
View File

@@ -0,0 +1,751 @@
/*
* drivers/firmware/qemu_fw_cfg.c
*
* Copyright 2015 Carnegie Mellon University
*
* Expose entries from QEMU's firmware configuration (fw_cfg) device in
* sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/...").
*
* The fw_cfg device may be instantiated via either an ACPI node (on x86
* and select subsets of aarch64), a Device Tree node (on arm), or using
* a kernel module (or command line) parameter with the following syntax:
*
* [fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>]
* or
* [fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>]
*
* where:
* <size> := size of ioport or mmio range
* <base> := physical base address of ioport or mmio range
* <ctrl_off> := (optional) offset of control register
* <data_off> := (optional) offset of data register
*
* e.g.:
* fw_cfg.ioport=2@0x510:0:1 (the default on x86)
* or
* fw_cfg.mmio=0xA@0x9020000:8:0 (the default on arm)
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/ioport.h>
MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
MODULE_LICENSE("GPL");
/* selector key values for "well-known" fw_cfg entries */
#define FW_CFG_SIGNATURE 0x00
#define FW_CFG_ID 0x01
#define FW_CFG_FILE_DIR 0x19
/* size in bytes of fw_cfg signature */
#define FW_CFG_SIG_SIZE 4
/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
#define FW_CFG_MAX_FILE_PATH 56
/* fw_cfg file directory entry type */
struct fw_cfg_file {
u32 size;
u16 select;
u16 reserved;
char name[FW_CFG_MAX_FILE_PATH];
};
/* fw_cfg device i/o register addresses */
static bool fw_cfg_is_mmio;
static phys_addr_t fw_cfg_p_base;
static resource_size_t fw_cfg_p_size;
static void __iomem *fw_cfg_dev_base;
static void __iomem *fw_cfg_reg_ctrl;
static void __iomem *fw_cfg_reg_data;
/* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
static DEFINE_MUTEX(fw_cfg_dev_lock);
/* pick appropriate endianness for selector key */
static inline u16 fw_cfg_sel_endianness(u16 key)
{
return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
}
/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
static inline void fw_cfg_read_blob(u16 key,
void *buf, loff_t pos, size_t count)
{
mutex_lock(&fw_cfg_dev_lock);
iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
while (pos-- > 0)
ioread8(fw_cfg_reg_data);
ioread8_rep(fw_cfg_reg_data, buf, count);
mutex_unlock(&fw_cfg_dev_lock);
}
/* clean up fw_cfg device i/o */
static void fw_cfg_io_cleanup(void)
{
if (fw_cfg_is_mmio) {
iounmap(fw_cfg_dev_base);
release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
} else {
ioport_unmap(fw_cfg_dev_base);
release_region(fw_cfg_p_base, fw_cfg_p_size);
}
}
/* arch-specific ctrl & data register offsets are not available in ACPI, DT */
#if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CFG_DATA_OFF))
# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
# define FW_CFG_CTRL_OFF 0x08
# define FW_CFG_DATA_OFF 0x00
# elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
# define FW_CFG_CTRL_OFF 0x00
# define FW_CFG_DATA_OFF 0x02
# elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
# define FW_CFG_CTRL_OFF 0x00
# define FW_CFG_DATA_OFF 0x01
# else
# warning "QEMU FW_CFG may not be available on this architecture!"
# define FW_CFG_CTRL_OFF 0x00
# define FW_CFG_DATA_OFF 0x01
# endif
#endif
/* initialize fw_cfg device i/o from platform data */
static int fw_cfg_do_platform_probe(struct platform_device *pdev)
{
char sig[FW_CFG_SIG_SIZE];
struct resource *range, *ctrl, *data;
/* acquire i/o range details */
fw_cfg_is_mmio = false;
range = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!range) {
fw_cfg_is_mmio = true;
range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!range)
return -EINVAL;
}
fw_cfg_p_base = range->start;
fw_cfg_p_size = resource_size(range);
if (fw_cfg_is_mmio) {
if (!request_mem_region(fw_cfg_p_base,
fw_cfg_p_size, "fw_cfg_mem"))
return -EBUSY;
fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size);
if (!fw_cfg_dev_base) {
release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
return -EFAULT;
}
} else {
if (!request_region(fw_cfg_p_base,
fw_cfg_p_size, "fw_cfg_io"))
return -EBUSY;
fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size);
if (!fw_cfg_dev_base) {
release_region(fw_cfg_p_base, fw_cfg_p_size);
return -EFAULT;
}
}
/* were custom register offsets provided (e.g. on the command line)? */
ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
if (ctrl && data) {
fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
fw_cfg_reg_data = fw_cfg_dev_base + data->start;
} else {
/* use architecture-specific offsets */
fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF;
fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
}
/* verify fw_cfg device signature */
fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);
if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
fw_cfg_io_cleanup();
return -ENODEV;
}
return 0;
}
/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
static u32 fw_cfg_rev;
static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
{
return sprintf(buf, "%u\n", fw_cfg_rev);
}
static const struct {
struct attribute attr;
ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
} fw_cfg_rev_attr = {
.attr = { .name = "rev", .mode = S_IRUSR },
.show = fw_cfg_showrev,
};
/* fw_cfg_sysfs_entry type */
struct fw_cfg_sysfs_entry {
struct kobject kobj;
struct fw_cfg_file f;
struct list_head list;
};
/* get fw_cfg_sysfs_entry from kobject member */
static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
{
return container_of(kobj, struct fw_cfg_sysfs_entry, kobj);
}
/* fw_cfg_sysfs_attribute type */
struct fw_cfg_sysfs_attribute {
struct attribute attr;
ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf);
};
/* get fw_cfg_sysfs_attribute from attribute member */
static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr)
{
return container_of(attr, struct fw_cfg_sysfs_attribute, attr);
}
/* global cache of fw_cfg_sysfs_entry objects */
static LIST_HEAD(fw_cfg_entry_cache);
/* kobjects removed lazily by kernel, mutual exclusion needed */
static DEFINE_SPINLOCK(fw_cfg_cache_lock);
static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry)
{
spin_lock(&fw_cfg_cache_lock);
list_add_tail(&entry->list, &fw_cfg_entry_cache);
spin_unlock(&fw_cfg_cache_lock);
}
static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry)
{
spin_lock(&fw_cfg_cache_lock);
list_del(&entry->list);
spin_unlock(&fw_cfg_cache_lock);
}
static void fw_cfg_sysfs_cache_cleanup(void)
{
struct fw_cfg_sysfs_entry *entry, *next;
list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) {
/* will end up invoking fw_cfg_sysfs_cache_delist()
* via each object's release() method (i.e. destructor)
*/
kobject_put(&entry->kobj);
}
}
/* default_attrs: per-entry attributes and show methods */
#define FW_CFG_SYSFS_ATTR(_attr) \
struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \
.attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \
.show = fw_cfg_sysfs_show_##_attr, \
}
static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf)
{
return sprintf(buf, "%u\n", e->f.size);
}
static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
{
return sprintf(buf, "%u\n", e->f.select);
}
static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
{
return sprintf(buf, "%s\n", e->f.name);
}
static FW_CFG_SYSFS_ATTR(size);
static FW_CFG_SYSFS_ATTR(key);
static FW_CFG_SYSFS_ATTR(name);
static struct attribute *fw_cfg_sysfs_entry_attrs[] = {
&fw_cfg_sysfs_attr_size.attr,
&fw_cfg_sysfs_attr_key.attr,
&fw_cfg_sysfs_attr_name.attr,
NULL,
};
/* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */
static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a,
char *buf)
{
struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
struct fw_cfg_sysfs_attribute *attr = to_attr(a);
return attr->show(entry, buf);
}
static const struct sysfs_ops fw_cfg_sysfs_attr_ops = {
.show = fw_cfg_sysfs_attr_show,
};
/* release: destructor, to be called via kobject_put() */
static void fw_cfg_sysfs_release_entry(struct kobject *kobj)
{
struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
fw_cfg_sysfs_cache_delist(entry);
kfree(entry);
}
/* kobj_type: ties together all properties required to register an entry */
static struct kobj_type fw_cfg_sysfs_entry_ktype = {
.default_attrs = fw_cfg_sysfs_entry_attrs,
.sysfs_ops = &fw_cfg_sysfs_attr_ops,
.release = fw_cfg_sysfs_release_entry,
};
/* raw-read method and attribute */
static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t count)
{
struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
if (pos > entry->f.size)
return -EINVAL;
if (count > entry->f.size - pos)
count = entry->f.size - pos;
fw_cfg_read_blob(entry->f.select, buf, pos, count);
return count;
}
static struct bin_attribute fw_cfg_sysfs_attr_raw = {
.attr = { .name = "raw", .mode = S_IRUSR },
.read = fw_cfg_sysfs_read_raw,
};
/*
* Create a kset subdirectory matching each '/' delimited dirname token
* in 'name', starting with sysfs kset/folder 'dir'; At the end, create
* a symlink directed at the given 'target'.
* NOTE: We do this on a best-effort basis, since 'name' is not guaranteed
* to be a well-behaved path name. Whenever a symlink vs. kset directory
* name collision occurs, the kernel will issue big scary warnings while
* refusing to add the offending link or directory. We follow up with our
* own, slightly less scary error messages explaining the situation :)
*/
static int fw_cfg_build_symlink(struct kset *dir,
struct kobject *target, const char *name)
{
int ret;
struct kset *subdir;
struct kobject *ko;
char *name_copy, *p, *tok;
if (!dir || !target || !name || !*name)
return -EINVAL;
/* clone a copy of name for parsing */
name_copy = p = kstrdup(name, GFP_KERNEL);
if (!name_copy)
return -ENOMEM;
/* create folders for each dirname token, then symlink for basename */
while ((tok = strsep(&p, "/")) && *tok) {
/* last (basename) token? If so, add symlink here */
if (!p || !*p) {
ret = sysfs_create_link(&dir->kobj, target, tok);
break;
}
/* does the current dir contain an item named after tok ? */
ko = kset_find_obj(dir, tok);
if (ko) {
/* drop reference added by kset_find_obj */
kobject_put(ko);
/* ko MUST be a kset - we're about to use it as one ! */
if (ko->ktype != dir->kobj.ktype) {
ret = -EINVAL;
break;
}
/* descend into already existing subdirectory */
dir = to_kset(ko);
} else {
/* create new subdirectory kset */
subdir = kzalloc(sizeof(struct kset), GFP_KERNEL);
if (!subdir) {
ret = -ENOMEM;
break;
}
subdir->kobj.kset = dir;
subdir->kobj.ktype = dir->kobj.ktype;
ret = kobject_set_name(&subdir->kobj, "%s", tok);
if (ret) {
kfree(subdir);
break;
}
ret = kset_register(subdir);
if (ret) {
kfree(subdir);
break;
}
/* descend into newly created subdirectory */
dir = subdir;
}
}
/* we're done with cloned copy of name */
kfree(name_copy);
return ret;
}
/* recursively unregister fw_cfg/by_name/ kset directory tree */
static void fw_cfg_kset_unregister_recursive(struct kset *kset)
{
struct kobject *k, *next;
list_for_each_entry_safe(k, next, &kset->list, entry)
/* all set members are ksets too, but check just in case... */
if (k->ktype == kset->kobj.ktype)
fw_cfg_kset_unregister_recursive(to_kset(k));
/* symlinks are cleanly and automatically removed with the directory */
kset_unregister(kset);
}
/* kobjects & kset representing top-level, by_key, and by_name folders */
static struct kobject *fw_cfg_top_ko;
static struct kobject *fw_cfg_sel_ko;
static struct kset *fw_cfg_fname_kset;
/* register an individual fw_cfg file */
static int fw_cfg_register_file(const struct fw_cfg_file *f)
{
int err;
struct fw_cfg_sysfs_entry *entry;
/* allocate new entry */
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return -ENOMEM;
/* set file entry information */
memcpy(&entry->f, f, sizeof(struct fw_cfg_file));
/* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
fw_cfg_sel_ko, "%d", entry->f.select);
if (err)
goto err_register;
/* add raw binary content access */
err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw);
if (err)
goto err_add_raw;
/* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */
fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->f.name);
/* success, add entry to global cache */
fw_cfg_sysfs_cache_enlist(entry);
return 0;
err_add_raw:
kobject_del(&entry->kobj);
err_register:
kfree(entry);
return err;
}
/* iterate over all fw_cfg directory entries, registering each one */
static int fw_cfg_register_dir_entries(void)
{
int ret = 0;
u32 count, i;
struct fw_cfg_file *dir;
size_t dir_size;
fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count));
count = be32_to_cpu(count);
dir_size = count * sizeof(struct fw_cfg_file);
dir = kmalloc(dir_size, GFP_KERNEL);
if (!dir)
return -ENOMEM;
fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size);
for (i = 0; i < count; i++) {
dir[i].size = be32_to_cpu(dir[i].size);
dir[i].select = be16_to_cpu(dir[i].select);
ret = fw_cfg_register_file(&dir[i]);
if (ret)
break;
}
kfree(dir);
return ret;
}
/* unregister top-level or by_key folder */
static inline void fw_cfg_kobj_cleanup(struct kobject *kobj)
{
kobject_del(kobj);
kobject_put(kobj);
}
static int fw_cfg_sysfs_probe(struct platform_device *pdev)
{
int err;
/* NOTE: If we supported multiple fw_cfg devices, we'd first create
* a subdirectory named after e.g. pdev->id, then hang per-device
* by_key (and by_name) subdirectories underneath it. However, only
* one fw_cfg device exist system-wide, so if one was already found
* earlier, we might as well stop here.
*/
if (fw_cfg_sel_ko)
return -EBUSY;
/* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */
err = -ENOMEM;
fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko);
if (!fw_cfg_sel_ko)
goto err_sel;
fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko);
if (!fw_cfg_fname_kset)
goto err_name;
/* initialize fw_cfg device i/o from platform data */
err = fw_cfg_do_platform_probe(pdev);
if (err)
goto err_probe;
/* get revision number, add matching top-level attribute */
fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev));
fw_cfg_rev = le32_to_cpu(fw_cfg_rev);
err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
if (err)
goto err_rev;
/* process fw_cfg file directory entry, registering each file */
err = fw_cfg_register_dir_entries();
if (err)
goto err_dir;
/* success */
pr_debug("fw_cfg: loaded.\n");
return 0;
err_dir:
fw_cfg_sysfs_cache_cleanup();
sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
err_rev:
fw_cfg_io_cleanup();
err_probe:
fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
err_name:
fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
err_sel:
return err;
}
static int fw_cfg_sysfs_remove(struct platform_device *pdev)
{
pr_debug("fw_cfg: unloading.\n");
fw_cfg_sysfs_cache_cleanup();
fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
fw_cfg_io_cleanup();
return 0;
}
static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
{ .compatible = "qemu,fw-cfg-mmio", },
{},
};
MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
#ifdef CONFIG_ACPI
static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
{ "QEMU0002", },
{},
};
MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
#endif
static struct platform_driver fw_cfg_sysfs_driver = {
.probe = fw_cfg_sysfs_probe,
.remove = fw_cfg_sysfs_remove,
.driver = {
.name = "fw_cfg",
.of_match_table = fw_cfg_sysfs_mmio_match,
.acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match),
},
};
#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
static struct platform_device *fw_cfg_cmdline_dev;
/* this probably belongs in e.g. include/linux/types.h,
* but right now we are the only ones doing it...
*/
#ifdef CONFIG_PHYS_ADDR_T_64BIT
#define __PHYS_ADDR_PREFIX "ll"
#else
#define __PHYS_ADDR_PREFIX ""
#endif
/* use special scanf/printf modifier for phys_addr_t, resource_size_t */
#define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
":%" __PHYS_ADDR_PREFIX "i" \
":%" __PHYS_ADDR_PREFIX "i%n"
#define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
"0x%" __PHYS_ADDR_PREFIX "x"
#define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \
":%" __PHYS_ADDR_PREFIX "u" \
":%" __PHYS_ADDR_PREFIX "u"
static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
{
struct resource res[3] = {};
char *str;
phys_addr_t base;
resource_size_t size, ctrl_off, data_off;
int processed, consumed = 0;
/* only one fw_cfg device can exist system-wide, so if one
* was processed on the command line already, we might as
* well stop here.
*/
if (fw_cfg_cmdline_dev) {
/* avoid leaking previously registered device */
platform_device_unregister(fw_cfg_cmdline_dev);
return -EINVAL;
}
/* consume "<size>" portion of command line argument */
size = memparse(arg, &str);
/* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
processed = sscanf(str, PH_ADDR_SCAN_FMT,
&base, &consumed,
&ctrl_off, &data_off, &consumed);
/* sscanf() must process precisely 1 or 3 chunks:
* <base> is mandatory, optionally followed by <ctrl_off>
* and <data_off>;
* there must be no extra characters after the last chunk,
* so str[consumed] must be '\0'.
*/
if (str[consumed] ||
(processed != 1 && processed != 3))
return -EINVAL;
res[0].start = base;
res[0].end = base + size - 1;
res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM :
IORESOURCE_IO;
/* insert register offsets, if provided */
if (processed > 1) {
res[1].name = "ctrl";
res[1].start = ctrl_off;
res[1].flags = IORESOURCE_REG;
res[2].name = "data";
res[2].start = data_off;
res[2].flags = IORESOURCE_REG;
}
/* "processed" happens to nicely match the number of resources
* we need to pass in to this platform device.
*/
fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg",
PLATFORM_DEVID_NONE, res, processed);
if (IS_ERR(fw_cfg_cmdline_dev))
return PTR_ERR(fw_cfg_cmdline_dev);
return 0;
}
static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
{
/* stay silent if device was not configured via the command
* line, or if the parameter name (ioport/mmio) doesn't match
* the device setting
*/
if (!fw_cfg_cmdline_dev ||
(!strcmp(kp->name, "mmio") ^
(fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM)))
return 0;
switch (fw_cfg_cmdline_dev->num_resources) {
case 1:
return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT,
resource_size(&fw_cfg_cmdline_dev->resource[0]),
fw_cfg_cmdline_dev->resource[0].start);
case 3:
return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT,
resource_size(&fw_cfg_cmdline_dev->resource[0]),
fw_cfg_cmdline_dev->resource[0].start,
fw_cfg_cmdline_dev->resource[1].start,
fw_cfg_cmdline_dev->resource[2].start);
}
/* Should never get here */
WARN(1, "Unexpected number of resources: %d\n",
fw_cfg_cmdline_dev->num_resources);
return 0;
}
static const struct kernel_param_ops fw_cfg_cmdline_param_ops = {
.set = fw_cfg_cmdline_set,
.get = fw_cfg_cmdline_get,
};
device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
#endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */
static int __init fw_cfg_sysfs_init(void)
{
/* create /sys/firmware/qemu_fw_cfg/ top level directory */
fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj);
if (!fw_cfg_top_ko)
return -ENOMEM;
return platform_driver_register(&fw_cfg_sysfs_driver);
}
static void __exit fw_cfg_sysfs_exit(void)
{
platform_driver_unregister(&fw_cfg_sysfs_driver);
#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
platform_device_unregister(fw_cfg_cmdline_dev);
#endif
/* clean up /sys/firmware/qemu_fw_cfg/ */
fw_cfg_kobj_cleanup(fw_cfg_top_ko);
}
module_init(fw_cfg_sysfs_init);
module_exit(fw_cfg_sysfs_exit);

19
fs/kernfs/dir.c
View File

@@ -691,15 +691,22 @@ static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
const unsigned char *path, const unsigned char *path,
const void *ns) const void *ns)
{ {
static char path_buf[PATH_MAX]; /* protected by kernfs_mutex */ size_t len;
size_t len = strlcpy(path_buf, path, PATH_MAX); char *p, *name;
char *p = path_buf;
char *name;
lockdep_assert_held(&kernfs_mutex); lockdep_assert_held(&kernfs_mutex);
if (len >= PATH_MAX) /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */
spin_lock_irq(&kernfs_rename_lock);
len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf));
if (len >= sizeof(kernfs_pr_cont_buf)) {
spin_unlock_irq(&kernfs_rename_lock);
return NULL; return NULL;
}
p = kernfs_pr_cont_buf;
while ((name = strsep(&p, "/")) && parent) { while ((name = strsep(&p, "/")) && parent) {
if (*name == '\0') if (*name == '\0')
@@ -707,6 +714,8 @@ static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
parent = kernfs_find_ns(parent, name, ns); parent = kernfs_find_ns(parent, name, ns);
} }
spin_unlock_irq(&kernfs_rename_lock);
return parent; return parent;
} }

8
include/linux/debugfs.h
View File

@@ -162,6 +162,14 @@ static inline struct dentry *debugfs_create_symlink(const char *name,
return ERR_PTR(-ENODEV); return ERR_PTR(-ENODEV);
} }
static inline struct dentry *debugfs_create_automount(const char *name,
struct dentry *parent,
struct vfsmount *(*f)(void *),
void *data)
{
return ERR_PTR(-ENODEV);
}
static inline void debugfs_remove(struct dentry *dentry) static inline void debugfs_remove(struct dentry *dentry)
{ } { }

1
lib/kobject.c
View File

@@ -861,6 +861,7 @@ struct kobject *kset_find_obj(struct kset *kset, const char *name)
spin_unlock(&kset->list_lock); spin_unlock(&kset->list_lock);
return ret; return ret;
} }
EXPORT_SYMBOL_GPL(kset_find_obj);
static void kset_release(struct kobject *kobj) static void kset_release(struct kobject *kobj)
{ {