7bc1e4d8d5
Add optional support to export the bootinfo used to boot the kernel in a "bootinfo" file in procfs. This is useful with kexec. This is based on the similar feature for ATAGS on ARM. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
80 lines
1.7 KiB
C
80 lines
1.7 KiB
C
/*
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* Based on arch/arm/kernel/atags_proc.c
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*/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/printk.h>
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#include <linux/proc_fs.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <asm/bootinfo.h>
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#include <asm/byteorder.h>
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static char bootinfo_tmp[1536] __initdata;
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static void *bootinfo_copy;
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static size_t bootinfo_size;
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static ssize_t bootinfo_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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return simple_read_from_buffer(buf, count, ppos, bootinfo_copy,
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bootinfo_size);
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}
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static const struct file_operations bootinfo_fops = {
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.read = bootinfo_read,
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.llseek = default_llseek,
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};
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void __init save_bootinfo(const struct bi_record *bi)
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{
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const void *start = bi;
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size_t size = sizeof(bi->tag);
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while (be16_to_cpu(bi->tag) != BI_LAST) {
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uint16_t n = be16_to_cpu(bi->size);
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size += n;
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bi = (struct bi_record *)((unsigned long)bi + n);
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}
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if (size > sizeof(bootinfo_tmp)) {
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pr_err("Cannot save %zu bytes of bootinfo\n", size);
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return;
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}
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pr_info("Saving %zu bytes of bootinfo\n", size);
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memcpy(bootinfo_tmp, start, size);
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bootinfo_size = size;
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}
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static int __init init_bootinfo_procfs(void)
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{
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/*
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* This cannot go into save_bootinfo() because kmalloc and proc don't
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* work yet when it is called.
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*/
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struct proc_dir_entry *pde;
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if (!bootinfo_size)
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return -EINVAL;
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bootinfo_copy = kmalloc(bootinfo_size, GFP_KERNEL);
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if (!bootinfo_copy)
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return -ENOMEM;
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memcpy(bootinfo_copy, bootinfo_tmp, bootinfo_size);
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pde = proc_create_data("bootinfo", 0400, NULL, &bootinfo_fops, NULL);
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if (!pde) {
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kfree(bootinfo_copy);
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return -ENOMEM;
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}
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return 0;
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}
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arch_initcall(init_bootinfo_procfs);
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