m68k: Add support to export bootinfo in procfs

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>
This commit is contained in:
Geert Uytterhoeven 2013-08-21 22:36:32 +02:00
parent 7d5f5fa276
commit 7bc1e4d8d5
5 changed files with 102 additions and 0 deletions

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@ -104,6 +104,13 @@ config KEXEC
interface is strongly in flux, so no good recommendation can be
made.
config BOOTINFO_PROC
bool "Export bootinfo in procfs"
depends on KEXEC && M68KCLASSIC
help
Say Y to export the bootinfo used to boot the kernel in a
"bootinfo" file in procfs. This is useful with kexec.
menu "Platform setup"
source arch/m68k/Kconfig.cpu

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@ -13,4 +13,16 @@
#include <uapi/asm/bootinfo.h>
#ifndef __ASSEMBLY__
#ifdef CONFIG_BOOTINFO_PROC
extern void save_bootinfo(const struct bi_record *bi);
#else
static inline void save_bootinfo(const struct bi_record *bi) {}
#endif
#endif /* __ASSEMBLY__ */
#endif /* _M68K_BOOTINFO_H */

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@ -23,4 +23,5 @@ obj-$(CONFIG_PCI) += pcibios.o
obj-$(CONFIG_HAS_DMA) += dma.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_BOOTINFO_PROC) += bootinfo_proc.o

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@ -0,0 +1,80 @@
/*
* Based on arch/arm/kernel/atags_proc.c
*/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/printk.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <asm/bootinfo.h>
#include <asm/byteorder.h>
static char bootinfo_tmp[1536] __initdata;
static void *bootinfo_copy;
static size_t bootinfo_size;
static ssize_t bootinfo_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
return simple_read_from_buffer(buf, count, ppos, bootinfo_copy,
bootinfo_size);
}
static const struct file_operations bootinfo_fops = {
.read = bootinfo_read,
.llseek = default_llseek,
};
void __init save_bootinfo(const struct bi_record *bi)
{
const void *start = bi;
size_t size = sizeof(bi->tag);
while (be16_to_cpu(bi->tag) != BI_LAST) {
uint16_t n = be16_to_cpu(bi->size);
size += n;
bi = (struct bi_record *)((unsigned long)bi + n);
}
if (size > sizeof(bootinfo_tmp)) {
pr_err("Cannot save %zu bytes of bootinfo\n", size);
return;
}
pr_info("Saving %zu bytes of bootinfo\n", size);
memcpy(bootinfo_tmp, start, size);
bootinfo_size = size;
}
static int __init init_bootinfo_procfs(void)
{
/*
* This cannot go into save_bootinfo() because kmalloc and proc don't
* work yet when it is called.
*/
struct proc_dir_entry *pde;
if (!bootinfo_size)
return -EINVAL;
bootinfo_copy = kmalloc(bootinfo_size, GFP_KERNEL);
if (!bootinfo_copy)
return -ENOMEM;
memcpy(bootinfo_copy, bootinfo_tmp, bootinfo_size);
pde = proc_create_data("bootinfo", 0400, NULL, &bootinfo_fops, NULL);
if (!pde) {
kfree(bootinfo_copy);
return -ENOMEM;
}
return 0;
}
arch_initcall(init_bootinfo_procfs);

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@ -146,6 +146,8 @@ static void __init m68k_parse_bootinfo(const struct bi_record *record)
{
uint16_t tag;
save_bootinfo(record);
while ((tag = be16_to_cpu(record->tag)) != BI_LAST) {
int unknown = 0;
const void *data = record->data;