linux-stable/drivers/firmware/qemu_fw_cfg.c
Nathan Chancellor fca41af18e qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute
fw_cfg_showrev() is called by an indirect call in kobj_attr_show(),
which violates clang's CFI checking because fw_cfg_showrev()'s second
parameter is 'struct attribute', whereas the ->show() member of 'struct
kobj_structure' expects the second parameter to be of type 'struct
kobj_attribute'.

$ cat /sys/firmware/qemu_fw_cfg/rev
3

$ dmesg | grep "CFI failure"
[   26.016832] CFI failure (target: fw_cfg_showrev+0x0/0x8):

Fix this by converting fw_cfg_rev_attr to 'struct kobj_attribute' where
this would have been caught automatically by the incompatible pointer
types compiler warning. Update fw_cfg_showrev() accordingly.

Fixes: 75f3e8e47f ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
Link: https://github.com/ClangBuiltLinux/linux/issues/1299
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210211194258.4137998-1-nathan@kernel.org
2021-06-29 13:25:20 -07:00

942 lines
25 KiB
C

/*
* 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:
*
* [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
* or
* [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_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
* <dma_off> := (optional) offset of dma register
*
* e.g.:
* qemu_fw_cfg.ioport=12@0x510:0:1:4 (the default on x86)
* or
* qemu_fw_cfg.mmio=16@0x9020000:8:0:16 (the default on arm)
*/
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <uapi/linux/qemu_fw_cfg.h>
#include <linux/delay.h>
#include <linux/crash_dump.h>
#include <linux/crash_core.h>
MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
MODULE_LICENSE("GPL");
/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
static u32 fw_cfg_rev;
/* 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;
static void __iomem *fw_cfg_reg_dma;
/* 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 void fw_cfg_sel_endianness(u16 key)
{
if (fw_cfg_is_mmio)
iowrite16be(key, fw_cfg_reg_ctrl);
else
iowrite16(key, fw_cfg_reg_ctrl);
}
#ifdef CONFIG_CRASH_CORE
static inline bool fw_cfg_dma_enabled(void)
{
return (fw_cfg_rev & FW_CFG_VERSION_DMA) && fw_cfg_reg_dma;
}
/* qemu fw_cfg device is sync today, but spec says it may become async */
static void fw_cfg_wait_for_control(struct fw_cfg_dma_access *d)
{
for (;;) {
u32 ctrl = be32_to_cpu(READ_ONCE(d->control));
/* do not reorder the read to d->control */
rmb();
if ((ctrl & ~FW_CFG_DMA_CTL_ERROR) == 0)
return;
cpu_relax();
}
}
static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control)
{
phys_addr_t dma;
struct fw_cfg_dma_access *d = NULL;
ssize_t ret = length;
d = kmalloc(sizeof(*d), GFP_KERNEL);
if (!d) {
ret = -ENOMEM;
goto end;
}
/* fw_cfg device does not need IOMMU protection, so use physical addresses */
*d = (struct fw_cfg_dma_access) {
.address = cpu_to_be64(address ? virt_to_phys(address) : 0),
.length = cpu_to_be32(length),
.control = cpu_to_be32(control)
};
dma = virt_to_phys(d);
iowrite32be((u64)dma >> 32, fw_cfg_reg_dma);
/* force memory to sync before notifying device via MMIO */
wmb();
iowrite32be(dma, fw_cfg_reg_dma + 4);
fw_cfg_wait_for_control(d);
if (be32_to_cpu(READ_ONCE(d->control)) & FW_CFG_DMA_CTL_ERROR) {
ret = -EIO;
}
end:
kfree(d);
return ret;
}
#endif
/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
static ssize_t fw_cfg_read_blob(u16 key,
void *buf, loff_t pos, size_t count)
{
u32 glk = -1U;
acpi_status status;
/* If we have ACPI, ensure mutual exclusion against any potential
* device access by the firmware, e.g. via AML methods:
*/
status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
/* Should never get here */
WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");
memset(buf, 0, count);
return -EINVAL;
}
mutex_lock(&fw_cfg_dev_lock);
fw_cfg_sel_endianness(key);
while (pos-- > 0)
ioread8(fw_cfg_reg_data);
ioread8_rep(fw_cfg_reg_data, buf, count);
mutex_unlock(&fw_cfg_dev_lock);
acpi_release_global_lock(glk);
return count;
}
#ifdef CONFIG_CRASH_CORE
/* write chunk of given fw_cfg blob (caller responsible for sanity-check) */
static ssize_t fw_cfg_write_blob(u16 key,
void *buf, loff_t pos, size_t count)
{
u32 glk = -1U;
acpi_status status;
ssize_t ret = count;
/* If we have ACPI, ensure mutual exclusion against any potential
* device access by the firmware, e.g. via AML methods:
*/
status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
/* Should never get here */
WARN(1, "%s: Failed to lock ACPI!\n", __func__);
return -EINVAL;
}
mutex_lock(&fw_cfg_dev_lock);
if (pos == 0) {
ret = fw_cfg_dma_transfer(buf, count, key << 16
| FW_CFG_DMA_CTL_SELECT
| FW_CFG_DMA_CTL_WRITE);
} else {
fw_cfg_sel_endianness(key);
ret = fw_cfg_dma_transfer(NULL, pos, FW_CFG_DMA_CTL_SKIP);
if (ret < 0)
goto end;
ret = fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE);
}
end:
mutex_unlock(&fw_cfg_dev_lock);
acpi_release_global_lock(glk);
return ret;
}
#endif /* CONFIG_CRASH_CORE */
/* 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
# define FW_CFG_DMA_OFF 0x10
# elif defined(CONFIG_PARISC) /* parisc */
# define FW_CFG_CTRL_OFF 0x00
# define FW_CFG_DATA_OFF 0x04
# 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
# define FW_CFG_DMA_OFF 0x04
# else
# error "QEMU FW_CFG not available on this architecture!"
# 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, *dma;
/* 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");
dma = platform_get_resource_byname(pdev, IORESOURCE_REG, "dma");
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;
}
if (dma)
fw_cfg_reg_dma = fw_cfg_dev_base + dma->start;
#ifdef FW_CFG_DMA_OFF
else
fw_cfg_reg_dma = fw_cfg_dev_base + FW_CFG_DMA_OFF;
#endif
/* verify fw_cfg device signature */
if (fw_cfg_read_blob(FW_CFG_SIGNATURE, sig,
0, FW_CFG_SIG_SIZE) < 0 ||
memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
fw_cfg_io_cleanup();
return -ENODEV;
}
return 0;
}
static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a,
char *buf)
{
return sprintf(buf, "%u\n", fw_cfg_rev);
}
static const struct kobj_attribute 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;
u32 size;
u16 select;
char name[FW_CFG_MAX_FILE_PATH];
struct list_head list;
};
#ifdef CONFIG_CRASH_CORE
static ssize_t fw_cfg_write_vmcoreinfo(const struct fw_cfg_file *f)
{
static struct fw_cfg_vmcoreinfo *data;
ssize_t ret;
data = kmalloc(sizeof(struct fw_cfg_vmcoreinfo), GFP_KERNEL);
if (!data)
return -ENOMEM;
*data = (struct fw_cfg_vmcoreinfo) {
.guest_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF),
.size = cpu_to_le32(VMCOREINFO_NOTE_SIZE),
.paddr = cpu_to_le64(paddr_vmcoreinfo_note())
};
/* spare ourself reading host format support for now since we
* don't know what else to format - host may ignore ours
*/
ret = fw_cfg_write_blob(be16_to_cpu(f->select), data,
0, sizeof(struct fw_cfg_vmcoreinfo));
kfree(data);
return ret;
}
#endif /* CONFIG_CRASH_CORE */
/* 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->size);
}
static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
{
return sprintf(buf, "%u\n", e->select);
}
static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
{
return sprintf(buf, "%s\n", e->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->size)
return -EINVAL;
if (count > entry->size - pos)
count = entry->size - pos;
return fw_cfg_read_blob(entry->select, buf, pos, 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;
#ifdef CONFIG_CRASH_CORE
if (fw_cfg_dma_enabled() &&
strcmp(f->name, FW_CFG_VMCOREINFO_FILENAME) == 0 &&
!is_kdump_kernel()) {
if (fw_cfg_write_vmcoreinfo(f) < 0)
pr_warn("fw_cfg: failed to write vmcoreinfo");
}
#endif
/* allocate new entry */
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return -ENOMEM;
/* set file entry information */
entry->size = be32_to_cpu(f->size);
entry->select = be16_to_cpu(f->select);
memcpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH);
/* 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->select);
if (err) {
kobject_put(&entry->kobj);
return err;
}
/* 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->name);
/* success, add entry to global cache */
fw_cfg_sysfs_cache_enlist(entry);
return 0;
err_add_raw:
kobject_del(&entry->kobj);
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;
__be32 files_count;
u32 count, i;
struct fw_cfg_file *dir;
size_t dir_size;
ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count,
0, sizeof(files_count));
if (ret < 0)
return ret;
count = be32_to_cpu(files_count);
dir_size = count * sizeof(struct fw_cfg_file);
dir = kmalloc(dir_size, GFP_KERNEL);
if (!dir)
return -ENOMEM;
ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, dir,
sizeof(files_count), dir_size);
if (ret < 0)
goto end;
for (i = 0; i < count; i++) {
ret = fw_cfg_register_file(&dir[i]);
if (ret)
break;
}
end:
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;
__le32 rev;
/* 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 */
err = fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev));
if (err < 0)
goto err_probe;
fw_cfg_rev = le32_to_cpu(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();
sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
fw_cfg_io_cleanup();
fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
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[] = {
{ FW_CFG_ACPI_DEVICE_ID, },
{},
};
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" \
":%" __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"
#define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \
":%" __PHYS_ADDR_PREFIX "u"
static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
{
struct resource res[4] = {};
char *str;
phys_addr_t base;
resource_size_t size, ctrl_off, data_off, dma_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>[:<dma_off>]]" chunks */
processed = sscanf(str, PH_ADDR_SCAN_FMT,
&base, &consumed,
&ctrl_off, &data_off, &consumed,
&dma_off, &consumed);
/* sscanf() must process precisely 1, 3 or 4 chunks:
* <base> is mandatory, optionally followed by <ctrl_off>
* and <data_off>, and <dma_off>;
* there must be no extra characters after the last chunk,
* so str[consumed] must be '\0'.
*/
if (str[consumed] ||
(processed != 1 && processed != 3 && processed != 4))
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;
}
if (processed > 3) {
res[3].name = "dma";
res[3].start = dma_off;
res[3].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);
return PTR_ERR_OR_ZERO(fw_cfg_cmdline_dev);
}
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);
case 4:
return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_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,
fw_cfg_cmdline_dev->resource[3].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)
{
int ret;
/* 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;
ret = platform_driver_register(&fw_cfg_sysfs_driver);
if (ret)
fw_cfg_kobj_cleanup(fw_cfg_top_ko);
return ret;
}
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);