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Commit 7f614cd1 authored by HATAYAMA Daisuke's avatar HATAYAMA Daisuke Committed by Linus Torvalds
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vmcore: treat memory chunks referenced by PT_LOAD program header entries in... 


vmcore: treat memory chunks referenced by PT_LOAD program header entries in page-size boundary in vmcore_list

Treat memory chunks referenced by PT_LOAD program header entries in
page-size boundary in vmcore_list.  Formally, for each range [start,
end], we set up the corresponding vmcore object in vmcore_list to
[rounddown(start, PAGE_SIZE), roundup(end, PAGE_SIZE)].

This change affects layout of /proc/vmcore.  The gaps generated by the
rearrangement are newly made visible to applications as holes.
Concretely, they are two ranges [rounddown(start, PAGE_SIZE), start] and
[end, roundup(end, PAGE_SIZE)].

Suppose variable m points at a vmcore object in vmcore_list, and
variable phdr points at the program header of PT_LOAD type the variable
m corresponds to.  Then, pictorially:

  m->offset                    +---------------+
                               | hole          |
phdr->p_offset =               +---------------+
  m->offset + (paddr - start)  |               |\
                               | kernel memory | phdr->p_memsz
                               |               |/
                               +---------------+
                               | hole          |
  m->offset + m->size          +---------------+

where m->offset and m->offset + m->size are always page-size aligned.

Signed-off-by: default avatarHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Lisa Mitchell <lisa.mitchell@hp.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f2bdacdd

fs/proc/vmcore.c

+22 −8
Original line number Diff line number Diff line
@@ -407,20 +407,27 @@ static int __init process_ptload_program_headers_elf64(char *elfptr, 
			phdr_ptr->p_memsz; /* Note sections */



	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {

		u64 paddr, start, end, size;



		if (phdr_ptr->p_type != PT_LOAD)

			continue;



		paddr = phdr_ptr->p_offset;

		start = rounddown(paddr, PAGE_SIZE);

		end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);

		size = end - start;



		/* Add this contiguous chunk of memory to vmcore list.*/

		new = get_new_element();

		if (!new)

			return -ENOMEM;

		new->paddr = phdr_ptr->p_offset;

		new->size = phdr_ptr->p_memsz;

		new->paddr = start;

		new->size = size;

		list_add_tail(&new->list, vc_list);



		/* Update the program header offset. */

		phdr_ptr->p_offset = vmcore_off;

		vmcore_off = vmcore_off + phdr_ptr->p_memsz;

		phdr_ptr->p_offset = vmcore_off + (paddr - start);

		vmcore_off = vmcore_off + size;

	}

	return 0;

}
@@ -443,20 +450,27 @@ static int __init process_ptload_program_headers_elf32(char *elfptr, 
			phdr_ptr->p_memsz; /* Note sections */



	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {

		u64 paddr, start, end, size;



		if (phdr_ptr->p_type != PT_LOAD)

			continue;



		paddr = phdr_ptr->p_offset;

		start = rounddown(paddr, PAGE_SIZE);

		end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);

		size = end - start;



		/* Add this contiguous chunk of memory to vmcore list.*/

		new = get_new_element();

		if (!new)

			return -ENOMEM;

		new->paddr = phdr_ptr->p_offset;

		new->size = phdr_ptr->p_memsz;

		new->paddr = start;

		new->size = size;

		list_add_tail(&new->list, vc_list);



		/* Update the program header offset */

		phdr_ptr->p_offset = vmcore_off;

		vmcore_off = vmcore_off + phdr_ptr->p_memsz;

		phdr_ptr->p_offset = vmcore_off + (paddr - start);

		vmcore_off = vmcore_off + size;

	}

	return 0;

}