diff options
Diffstat (limited to 'arch/arm/kernel/atags_proc.c')
-rw-r--r-- | arch/arm/kernel/atags_proc.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/arch/arm/kernel/atags_proc.c b/arch/arm/kernel/atags_proc.c new file mode 100644 index 0000000000..3ec2afe784 --- /dev/null +++ b/arch/arm/kernel/atags_proc.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/slab.h> +#include <linux/proc_fs.h> +#include <asm/setup.h> +#include <asm/types.h> +#include <asm/page.h> + +struct buffer { + size_t size; + char data[]; +}; + +static ssize_t atags_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct buffer *b = pde_data(file_inode(file)); + return simple_read_from_buffer(buf, count, ppos, b->data, b->size); +} + +static const struct proc_ops atags_proc_ops = { + .proc_read = atags_read, + .proc_lseek = default_llseek, +}; + +#define BOOT_PARAMS_SIZE 1536 +static char __initdata atags_copy[BOOT_PARAMS_SIZE]; + +void __init save_atags(const struct tag *tags) +{ + memcpy(atags_copy, tags, sizeof(atags_copy)); +} + +static int __init init_atags_procfs(void) +{ + /* + * This cannot go into save_atags() because kmalloc and proc don't work + * yet when it is called. + */ + struct proc_dir_entry *tags_entry; + struct tag *tag = (struct tag *)atags_copy; + struct buffer *b; + size_t size; + + if (tag->hdr.tag != ATAG_CORE) { + pr_info("No ATAGs?\n"); + return -EINVAL; + } + + for (; tag->hdr.size; tag = tag_next(tag)) + ; + + /* include the terminating ATAG_NONE */ + size = (char *)tag - atags_copy + sizeof(struct tag_header); + + WARN_ON(tag->hdr.tag != ATAG_NONE); + + b = kmalloc(sizeof(*b) + size, GFP_KERNEL); + if (!b) + goto nomem; + + b->size = size; + memcpy(b->data, atags_copy, size); + + tags_entry = proc_create_data("atags", 0400, NULL, &atags_proc_ops, b); + if (!tags_entry) + goto nomem; + + return 0; + +nomem: + kfree(b); + pr_err("Exporting ATAGs: not enough memory\n"); + + return -ENOMEM; +} +arch_initcall(init_atags_procfs); |