于 2013年05月15日 17:05, HATAYAMA Daisuke 写道:
> 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>
> ---
Acked-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
>
> 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 48886e6..6cf7fbd 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -406,20 +406,27 @@ static int __init process_ptload_program_headers_elf64(char *elfptr,
> vmcore_off = elfsz + roundup(phdr_ptr->p_memsz, PAGE_SIZE);
>
> 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;
> }
> @@ -441,20 +448,27 @@ static int __init process_ptload_program_headers_elf32(char *elfptr,
> vmcore_off = elfsz + roundup(phdr_ptr->p_memsz, PAGE_SIZE);
>
> 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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