lkml.org 
[lkml]   [2020]   [Oct]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/2] fs:regfs: add register easy filesystem
From
Date
Hi viro:

  Through regfs is very sample and easy,  but i think it is a Interest
,  could give  some suggestions?


Regards,

zc

在 2020/10/20 下午2:30, Zou Cao 写道:
> register filesystem is mapping the register into file dentry, it
> will use the io readio to get the register val. DBT file is use
> to decript the register tree, you can use it as follow:
>
> mount -t regfs -o dtb=test.dtb none /mnt
>
> test.dts:
> / {
>
> compatible = "hisilicon,hi6220-hikey", "hisilicon,hi6220";
> #address-cells = <0x2>;
> #size-cells = <0x2>;
> model = "HiKey Development Board";
>
> gic-v3-dist{
> reg = <0x0 0x8000000 0x0 0x10000>;
> GIC_CTRL {
> offset = <0x0>;
> };
> GICD_TYPER {
> offset = <0x4>;
> };
> };
> };
>
> it will create all regiter dentry file in /mnt
>
> Signed-off-by: Zou Cao <zoucao@linux.alibaba.com>
> ---
> fs/Kconfig | 1 +
> fs/Makefile | 1 +
> fs/regfs/Kconfig | 7 +
> fs/regfs/Makefile | 8 ++
> fs/regfs/file.c | 107 +++++++++++++++
> fs/regfs/inode.c | 354 +++++++++++++++++++++++++++++++++++++++++++++++++
> fs/regfs/internal.h | 32 +++++
> fs/regfs/regfs_inode.h | 32 +++++
> fs/regfs/supper.c | 71 ++++++++++
> 9 files changed, 613 insertions(+)
> create mode 100644 fs/regfs/Kconfig
> create mode 100644 fs/regfs/Makefile
> create mode 100644 fs/regfs/file.c
> create mode 100644 fs/regfs/inode.c
> create mode 100644 fs/regfs/internal.h
> create mode 100644 fs/regfs/regfs_inode.h
> create mode 100644 fs/regfs/supper.c
>
> diff --git a/fs/Kconfig b/fs/Kconfig
> index a88aa3a..d95acaf 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -324,6 +324,7 @@ endif # NETWORK_FILESYSTEMS
> source "fs/nls/Kconfig"
> source "fs/dlm/Kconfig"
> source "fs/unicode/Kconfig"
> +source "fs/regfs/Kconfig"
>
> config IO_WQ
> bool
> diff --git a/fs/Makefile b/fs/Makefile
> index 2ce5112..24f3878 100644
> --- a/fs/Makefile
> +++ b/fs/Makefile
> @@ -136,3 +136,4 @@ obj-$(CONFIG_EFIVAR_FS) += efivarfs/
> obj-$(CONFIG_EROFS_FS) += erofs/
> obj-$(CONFIG_VBOXSF_FS) += vboxsf/
> obj-$(CONFIG_ZONEFS_FS) += zonefs/
> +obj-$(CONFIG_REGFS_FS) += zonefs/
> diff --git a/fs/regfs/Kconfig b/fs/regfs/Kconfig
> new file mode 100644
> index 0000000..74ba85b
> --- /dev/null
> +++ b/fs/regfs/Kconfig
> @@ -0,0 +1,7 @@
> +config REGFS_FS
> + tristate "registers filesystem support"
> + depends on ARM64
> + help
> + regfs support the read and write register of device resource by
> + dentry filesystem, it is more easy to support bsp debug. it also
> + support to printk the register val when panic
> diff --git a/fs/regfs/Makefile b/fs/regfs/Makefile
> new file mode 100644
> index 0000000..26d5eef
> --- /dev/null
> +++ b/fs/regfs/Makefile
> @@ -0,0 +1,8 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +#
> +#Makefile for the linux ramfs routines.
> +#
> +
> +obj-y += regfs.o
> +
> +regfs-objs += inode.o file.o supper.o
> diff --git a/fs/regfs/file.c b/fs/regfs/file.c
> new file mode 100644
> index 0000000..6cd9f3d
> --- /dev/null
> +++ b/fs/regfs/file.c
> @@ -0,0 +1,107 @@
> +#include <linux/fs.h>
> +#include <linux/mm.h>
> +#include <linux/mpage.h>
> +#include <linux/writeback.h>
> +#include <linux/buffer_head.h>
> +#include <linux/kernel.h>
> +#include <linux/mm.h>
> +#include <linux/memcontrol.h>
> +#include <linux/iomap.h>
> +#include <linux/pagemap.h>
> +#include <linux/uio.h>
> +#include <linux/buffer_head.h>
> +#include <linux/dax.h>
> +#include <linux/writeback.h>
> +#include <linux/swap.h>
> +#include <linux/bio.h>
> +#include <linux/sched/signal.h>
> +#include <linux/migrate.h>
> +
> +#include "regfs_inode.h"
> +#include "internal.h"
> +
> +ssize_t regfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> +{
> + struct file *file = iocb->ki_filp;
> + struct inode *inode = file->f_mapping->host;
> + ssize_t ret;
> +
> + inode_lock(inode);
> + ret = generic_write_checks(iocb, from);
> + if (ret > 0)
> + ret = __generic_file_write_iter(iocb, from);
> + inode_unlock(inode);
> +
> + if (ret > 0)
> + ret = generic_write_sync(iocb, ret);
> + return ret;
> +}
> +
> +static ssize_t regfs_file_read(struct file *file, char __user *buf, size_t len, loff_t *ppos)
> +{
> + struct address_space *mapping = file->f_mapping;
> + struct regfs_inode_info *info = REGFS_I(mapping->host);
> + char str[64];
> + unsigned long val;
> +
> + val = readl_relaxed(info->base + info->offset);
> +
> + loc_debug("name:%s base:%p val:%lx\n"
> + , file->f_path.dentry->d_iname
> + , info->base + info->offset
> + , val);
> +
> + snprintf(str, 64, "%lx", val);
> +
> + return simple_read_from_buffer(buf, len, ppos, str, strlen(str));
> +}
> +
> +static ssize_t regfs_file_write(struct file *file, const char __user *buf, size_t len, loff_t *ppos)
> +{
> + struct address_space *mapping = file->f_mapping;
> + struct regfs_inode_info *info = REGFS_I(mapping->host);
> + char str[67];
> + unsigned long val = 0;
> + loff_t pos = *ppos;
> + size_t res;
> +
> + if (pos < 0)
> + return -EINVAL;
> + if (pos >= len || len > 66)
> + return 0;
> +
> + res = copy_from_user(str, buf, len);
> + if (res)
> + return -EFAULT;
> + str[len] = 0;
> +
> + if (kstrtoul(str, 16, &val) < 0)
> + return -EINVAL;
> +
> + writel_relaxed(val, info->base + info->offset);
> +
> + loc_debug("name:%s base:%p val:%lx\n"
> + , file->f_path.dentry->d_iname
> + , info->base + info->offset
> + , val);
> +
> + return len;
> +}
> +
> +const struct file_operations regfs_file_operations = {
> + .read = regfs_file_read,
> + .write = regfs_file_write,
> +};
> +
> +const struct inode_operations regfs_file_inode_operations = {
> + .setattr = simple_setattr,
> + .getattr = simple_getattr,
> +};
> +
> +const struct address_space_operations regfs_aops = {
> + .readpage = simple_readpage,
> + .write_begin = simple_write_begin,
> + .write_end = simple_write_end,
> + .set_page_dirty = __set_page_dirty_buffers,
> +};
> +
> diff --git a/fs/regfs/inode.c b/fs/regfs/inode.c
> new file mode 100644
> index 0000000..1643fcd
> --- /dev/null
> +++ b/fs/regfs/inode.c
> @@ -0,0 +1,354 @@
> +/*
> + * Resizable simple ram filesystem for Linux.
> + *
> + * Copyright (C) 2000 Linus Torvalds.
> + * 2000 Transmeta Corp.
> + *
> + * Usage limits added by David Gibson, Linuxcare Australia.
> + * This file is released under the GPL.
> + */
> +
> +/*
> + * NOTE! This filesystem is probably most useful
> + * not as a real filesystem, but as an example of
> + * how virtual filesystems can be written.
> + *
> + * It doesn't get much simpler than this. Consider
> + * that this file implements the full semantics of
> + * a POSIX-compliant read-write filesystem.
> + *
> + * Note in particular how the filesystem does not
> + * need to implement any data structures of its own
> + * to keep track of the virtual data: using the VFS
> + * caches is sufficient.
> + */
> +
> +#include <linux/fs.h>
> +#include <linux/pagemap.h>
> +#include <linux/highmem.h>
> +#include <linux/time.h>
> +#include <linux/init.h>
> +#include <linux/string.h>
> +#include <linux/backing-dev.h>
> +#include <linux/sched.h>
> +#include <linux/parser.h>
> +#include <linux/magic.h>
> +#include <linux/slab.h>
> +#include <linux/kernel.h>
> +#include <linux/of.h>
> +#include <linux/of_fdt.h>
> +#include <linux/libfdt.h>
> +#include <asm/uaccess.h>
> +#include <linux/module.h>
> +#include "regfs_inode.h"
> +#include "internal.h"
> +
> +static LIST_HEAD(regfs_head);
> +
> +static const struct inode_operations regfs_dir_inode_operations;
> +int regfs_debug;
> +module_param(regfs_debug, int, S_IRUGO);
> +MODULE_PARM_DESC(regfs_debug, "enable regfs debug mode");
> +
> +struct inode *regfs_get_inode(struct super_block *sb, const struct inode *dir, umode_t mode, dev_t dev)
> +{
> + struct inode *inode = new_inode(sb);
> +
> + if (inode) {
> + inode->i_ino = get_next_ino();
> + inode_init_owner(inode, dir, mode);
> + inode->i_mapping->a_ops = &regfs_aops;
> + //inode->i_mapping->backing_dev_info = &regfs_backing_dev_info;
> + mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
> + mapping_set_unevictable(inode->i_mapping);
> + inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
> + switch (mode & S_IFMT) {
> + default:
> + init_special_inode(inode, mode, dev);
> + break;
> + case S_IFREG:
> + inode->i_op = &regfs_file_inode_operations;
> + inode->i_fop = &regfs_file_operations;
> + break;
> + case S_IFDIR:
> + inode->i_op = &regfs_dir_inode_operations;
> + inode->i_fop = &simple_dir_operations;
> +
> + /* directory inodes start off with i_nlink == 2 (for "." entry) */
> + inc_nlink(inode);
> + break;
> + case S_IFLNK:
> + inode->i_op = &page_symlink_inode_operations;
> + break;
> + }
> + }
> +
> + return inode;
> +}
> +
> +static const struct inode_operations regfs_dir_inode_operations = {
> + .lookup = simple_lookup,
> +};
> +
> +static struct dentry *new_dentry_create(struct super_block *sb, struct dentry *parent,
> + const char *name, bool is_dir, struct res_data *res)
> +{
> + struct dentry *dentry;
> + struct inode *inode;
> + struct regfs_inode_info *ei;
> + struct regfs_fs_info *fsi = sb->s_fs_info;
> +
> + dentry = d_alloc_name(parent, name);
> + if (!dentry)
> + return NULL;
> +
> + inode = new_inode(sb);
> + if (!inode)
> + goto out;
> +
> + ei = REGFS_I(inode);
> + inode->i_ino = get_next_ino();;
> + inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
> + inode->i_uid = GLOBAL_ROOT_UID;
> + inode->i_gid = GLOBAL_ROOT_GID;
> + if (is_dir) {
> + inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR;
> + inode->i_op = &regfs_dir_inode_operations;
> + inode->i_fop = &simple_dir_operations;
> + list_add(&ei->list, &fsi->list);
> + } else {
> + inode->i_mode = S_IFREG | S_IRUGO | S_IWUSR;
> + inode->i_op = &regfs_file_inode_operations;
> + inode->i_fop = &regfs_file_operations;
> + inc_nlink(inode);
> + }
> + ei->base = (void *)res->base;
> + ei->offset = res->offset;
> + ei->type = res->type;
> +
> + d_add(dentry, inode);
> +
> + loc_debug("new dentry io base:%llx offset:%llx ei:%llx\n", (u64)ei->base, (u64)ei->offset, (u64)ei);
> + return dentry;
> +out:
> + dput(dentry);
> + return NULL;
> +}
> +
> +static void node_transfer_dentry(struct super_block *sb)
> +{
> + struct regfs_fs_info *fsi = sb->s_fs_info;
> + void *blob = fsi->dtb_buf;
> + const char *pathp;
> + int node_offset, depth = -1;
> + struct dentry *parent = NULL;
> + u64 parent_base;
> +
> + for (node_offset = fdt_next_node(blob, -1, &depth);
> + node_offset >= 0 && depth >= 0;
> + node_offset = fdt_next_node(blob, node_offset, &depth)) {
> +
> + const struct fdt_property *prop;
> + struct res_data res;
> +
> + pathp = fdt_get_name(blob, node_offset, NULL);
> + prop = (void *)fdt_getprop(blob, node_offset, "reg", NULL);
> +
> + if (prop) {
> + unsigned long phys;
> +
> + phys = fdt32_to_cpu(((const __be32 *)prop)[1]);
> + res.type = RES_TYPE_RANGE;
> + res.offset = fdt32_to_cpu(((const __be32 *)prop)[3]);
> + res.base = (u64)ioremap(phys, res.offset);
> +
> + if (!res.base) {
> + parent = NULL;
> + parent_base = 0;
> + continue;
> + }
> +
> + loc_debug("%s reg:%lx size:%lx map:%llx\n\n", pathp
> + , (unsigned long) fdt32_to_cpu(((const __be32 *)prop)[1])
> + , (unsigned long) fdt32_to_cpu(((const __be32 *)prop)[3])
> + , (u64)res.base);
> +
> + parent = new_dentry_create(sb, sb->s_root, (const char *)pathp, true, &res);
> + parent_base = res.base;
> +
> + } else {
> + // parent dentry is create failed, igonre all child dentry
> + if (!parent)
> + continue;
> +
> + prop = (void *)fdt_getprop(blob, node_offset, "offset", NULL);
> + if (prop) {
> +
> + res.offset = fdt32_to_cpu(*(const __be32 *)prop);
> + res.base = parent_base;
> + res.type = RES_TYPE_ITEM;
> +
> + new_dentry_create(sb, parent, (const char *) pathp, false, &res);
> + loc_debug("%s offset:%lx\n", pathp, (unsigned long)fdt32_to_cpu(*(const __be32 *)prop));
> + }
> + }
> + }
> +}
> +
> +static int parse_options(char *options, struct super_block *sb)
> +{
> + char *p;
> + int ret = -EINVAL;
> + struct regfs_fs_info *fsi;
> + size_t msize = INT_MAX;
> +
> + fsi = sb->s_fs_info;
> +
> + if (!options)
> + return -EINVAL;
> +
> + while ((p = strsep(&options, ",")) != NULL) {
> + char *name, *name_val;
> +
> + name = strsep(&p, "=");
> + if (name == NULL)
> + goto failed;
> +
> + name_val = strsep(&p, "=");
> + if (name_val == NULL)
> + goto failed;
> +
> + //get resource address
> + if (!strcmp(name, "dtb")) {
> + ret = kernel_read_file_from_path(name_val, &fsi->dtb_buf, &fsi->dtb_len, msize, READING_UNKNOWN);
> + if (ret) {
> + pr_err("load %s failed\n", name_val);
> + goto failed;
> + }
> + } else
> + goto failed;
> + };
> +
> + return 0;
> +
> +failed:
> + return ret;
> +}
> +
> +int regfs_fill_super(struct super_block *sb, void *data, int silent)
> +{
> + struct regfs_fs_info *fsi;
> + struct inode *inode;
> + int err;
> +
> + fsi = kzalloc(sizeof(struct regfs_fs_info), GFP_KERNEL);
> + if (!fsi)
> + return -ENOMEM;
> +
> + sb->s_fs_info = fsi;
> + fsi->sb = sb;
> +
> + err = parse_options((char *)data, sb);
> + if (err)
> + goto out;
> +
> + sb->s_maxbytes = MAX_LFS_FILESIZE;
> + sb->s_blocksize = PAGE_SIZE;
> + sb->s_blocksize_bits = PAGE_SHIFT;
> + sb->s_magic = RAMFS_MAGIC;
> + sb->s_op = &regfs_ops;
> + sb->s_time_gran = 1;
> +
> + inode = regfs_get_inode(sb, NULL, S_IFDIR, 0);
> + sb->s_root = d_make_root(inode);
> + if (!sb->s_root)
> + goto out;
> +
> + INIT_LIST_HEAD(&fsi->list);
> + INIT_LIST_HEAD(&fsi->regfs_head);
> + list_add(&fsi->regfs_head, &regfs_head);
> +
> + return 0;
> +
> +out:
> + if (fsi)
> + kfree(fsi);
> +
> + return err;
> +}
> +
> +struct dentry *regfs_mount(struct file_system_type *fs_type,
> + int flags, const char *dev_name, void *data)
> +{
> + struct dentry *root_dentry;
> + struct super_block *sb;
> +
> + root_dentry = mount_nodev(fs_type, flags, data, regfs_fill_super);
> +
> + sb = root_dentry->d_sb;
> +
> + if (sb->s_root) {
> + node_transfer_dentry(sb);
> + } else
> + return NULL;
> +
> + return root_dentry;
> +}
> +
> +static void regfs_kill_sb(struct super_block *sb)
> +{
> + struct regfs_fs_info *fsi = sb->s_fs_info;
> + struct regfs_inode_info *info_res;
> +
> + list_for_each_entry(info_res, &fsi->list, list)
> + iounmap(info_res->base);
> +
> + if (fsi) {
> + if (fsi->dtb_buf)
> + vfree(fsi->dtb_buf);
> + list_del(&fsi->regfs_head);
> + kfree(sb->s_fs_info);
> + }
> + kill_litter_super(sb);
> +}
> +
> +static struct file_system_type regfs_fs_type = {
> + .name = "regfs",
> + .mount = regfs_mount,
> + .kill_sb = regfs_kill_sb,
> + .fs_flags = FS_USERNS_MOUNT,
> +};
> +
> +static void init_once(void *foo)
> +{
> + struct regfs_inode_info *ei = (struct regfs_inode_info *) foo;
> +
> + inode_init_once(&ei->vfs_inode);
> +}
> +
> +static int __init init_regfs_fs(void)
> +{
> +
> + regfs_inode_cachep = kmem_cache_create_usercopy("regfs_inode_cache",
> + sizeof(struct regfs_inode_info), 0,
> + (SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT),
> + 0, 0, init_once);
> +
> + if (!regfs_inode_cachep)
> + return -ENOMEM;
> +
> + return register_filesystem(&regfs_fs_type);
> +}
> +
> +static void __exit exit_regfs_fs(void)
> +{
> + unregister_filesystem(&regfs_fs_type);
> + rcu_barrier();
> + kmem_cache_destroy(regfs_inode_cachep);
> +}
> +
> +module_init(init_regfs_fs);
> +module_exit(exit_regfs_fs);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Zou Cao<zoucaox@linux.alibaba.com>");
> diff --git a/fs/regfs/internal.h b/fs/regfs/internal.h
> new file mode 100644
> index 0000000..61577bb
> --- /dev/null
> +++ b/fs/regfs/internal.h
> @@ -0,0 +1,32 @@
> +#ifndef __INTERNAL_H__
> +#define __INTERNAL_H__
> +
> +#define loc_debug(fmt, ...) \
> + do { \
> + if (regfs_debug) \
> + printk(fmt, ##__VA_ARGS__); \
> + } while (0)
> +
> +struct regfs_fs_info {
> + struct super_block *sb;
> + void *dtb_buf;
> + u64 dtb_len;
> + u64 iomem;
> + u64 size;
> + // supper ifs list
> + struct list_head regfs_head;
> + // io map list of inode
> + struct list_head list;
> +};
> +
> +#define RAMFS_DEFAULT_MODE 0755
> +
> +extern int regfs_debug;
> +extern const struct address_space_operations regfs_aops;
> +extern const struct inode_operations regfs_file_inode_operations;
> +extern const struct file_operations regfs_file_operations;
> +extern const struct super_operations regfs_ops;
> +extern struct kmem_cache *regfs_inode_cachep;
> +int regfs_supper_init(void);
> +
> +#endif
> diff --git a/fs/regfs/regfs_inode.h b/fs/regfs/regfs_inode.h
> new file mode 100644
> index 0000000..0883e05
> --- /dev/null
> +++ b/fs/regfs/regfs_inode.h
> @@ -0,0 +1,32 @@
> +#ifndef __REGFS_INODE_H__
> +#define __REGFS_INODE_H__
> +
> +enum res_type {
> + RES_TYPE_NONE = 0,
> + RES_TYPE_RANGE,
> + RES_TYPE_ITEM,
> +};
> +
> +struct regfs_inode_info {
> + unsigned long flag;
> + struct inode vfs_inode;
> + void __iomem *base;
> + u64 offset;
> + u64 val; //for panic save
> + struct list_head list; //inode list
> + enum res_type type;
> +};
> +
> +struct res_data {
> + enum res_type type;
> + u64 base;
> + u64 offset;
> +};
> +
> +static inline struct regfs_inode_info *REGFS_I(struct inode *inode)
> +{
> + return container_of(inode, struct regfs_inode_info, vfs_inode);
> +}
> +
> +#endif
> +
> diff --git a/fs/regfs/supper.c b/fs/regfs/supper.c
> new file mode 100644
> index 0000000..35733b6
> --- /dev/null
> +++ b/fs/regfs/supper.c
> @@ -0,0 +1,71 @@
> +#include <linux/fs.h>
> +#include <linux/pagemap.h>
> +#include <linux/highmem.h>
> +#include <linux/time.h>
> +#include <linux/init.h>
> +#include <linux/string.h>
> +#include <linux/backing-dev.h>
> +#include <linux/sched.h>
> +#include <linux/parser.h>
> +#include <linux/magic.h>
> +#include <linux/slab.h>
> +#include <linux/kernel.h>
> +#include <linux/uaccess.h>
> +#include <linux/module.h>
> +#include <linux/iversion.h>
> +#include "regfs_inode.h"
> +#include "internal.h"
> +
> +struct kmem_cache *regfs_inode_cachep;
> +
> +/*
> + * Display the mount options in /proc/mounts.
> + */
> +
> +static struct inode *regfs_alloc_inode(struct super_block *sb)
> +{
> + struct regfs_inode_info *ei;
> +
> + ei = kmem_cache_alloc(regfs_inode_cachep, GFP_NOFS);
> + if (!ei)
> + return NULL;
> +
> + inode_set_iversion(&ei->vfs_inode, 1);
> + ei->type = RES_TYPE_NONE;
> +
> + return &ei->vfs_inode;
> +}
> +
> +static void regfs_i_callback(struct rcu_head *head)
> +{
> + struct inode *inode = container_of(head, struct inode, i_rcu);
> +
> + kmem_cache_free(regfs_inode_cachep, REGFS_I(inode));
> +}
> +
> +static void regfs_destroy_inode(struct inode *inode)
> +{
> + call_rcu(&inode->i_rcu, regfs_i_callback);
> +}
> +
> +static int regfs_write_inode(struct inode *inode, struct writeback_control *wbc)
> +{
> + return 0;
> +}
> +
> +static int regfs_drop_inode(struct inode *inode)
> +{
> + return generic_drop_inode(inode);
> +}
> +
> +const struct super_operations regfs_ops = {
> + .alloc_inode = regfs_alloc_inode,
> + .destroy_inode = regfs_destroy_inode,
> + .write_inode = regfs_write_inode,
> + .drop_inode = regfs_drop_inode,
> +};
> +
> +int regfs_supper_init(void)
> +{
> + return 0;
> +}

\
 
 \ /
  Last update: 2020-10-23 04:58    [W:0.086 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site