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Commit 7bc1e4d8 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven
Browse files

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: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 7d5f5fa2

arch/m68k/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -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

arch/m68k/include/asm/bootinfo.h

+12 −0
Original line number Diff line number Diff line
@@ -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 */

arch/m68k/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/m68k/kernel/bootinfo_proc.c

0 → 100644
+80 −0
Original line number Diff line number Diff line 
/*

 * 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);

arch/m68k/kernel/setup_mm.c

+2 −0
Original line number Diff line number Diff line
@@ -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;