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: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
fs/proc/vmcore.c | 30 ++++++++++++++++++++++--------
1 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 80fea97..686068d 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -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;
}
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