Re: [PATCH v2 07/20] vmcore: copy non page-size aligned head and tail pages in 2nd kernel
From: Zhang Yanfei Subject: Re: [PATCH v2 07/20] vmcore: copy non page-size aligned head and tail pages in 2nd kernel Date: Sun, 10 Mar 2013 14:16:51 +0800 > 于 2013年03月02日 16:36, HATAYAMA Daisuke 写道: >> /* Update the program header offset. */ >> phdr_ptr->p_offset = vmcore_off; >> -vmcore_off = vmcore_off + phdr_ptr->p_memsz; >> +vmcore_off +=roundup(end,PAGE_SIZE)-rounddown(start,PAGE_SIZE); > > Here the code changes phdr_ptr->p_offset to a new page-size aligned offset. > But it seems the phdr_ptr->p_paddr is still the non page-size aligned > physical address? Does the mismatch of a PT_LOAD segment and the physical > memory occur? > > Or, later in makedumpfile, it will check the phdr_ptr->paddr to see if it > is page-size aligned and also phdr_ptr->p_memsz to get the real memory size, > not including padding? > No, it doesn't happen. p_offset is made page-size aligned for requirement to user-space linear-address vs file offset. The requirement for physical address is handled internally in vmcore_list, which is transparent to to user-space. Thanks. HATAYAMA, Daisuke -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 07/20] vmcore: copy non page-size aligned head and tail pages in 2nd kernel
From: Zhang Yanfei zhangyan...@cn.fujitsu.com Subject: Re: [PATCH v2 07/20] vmcore: copy non page-size aligned head and tail pages in 2nd kernel Date: Sun, 10 Mar 2013 14:16:51 +0800 于 2013年03月02日 16:36, HATAYAMA Daisuke 写道: cut /* Update the program header offset. */ phdr_ptr-p_offset = vmcore_off; -vmcore_off = vmcore_off + phdr_ptr-p_memsz; +vmcore_off +=roundup(end,PAGE_SIZE)-rounddown(start,PAGE_SIZE); Here the code changes phdr_ptr-p_offset to a new page-size aligned offset. But it seems the phdr_ptr-p_paddr is still the non page-size aligned physical address? Does the mismatch of a PT_LOAD segment and the physical memory occur? Or, later in makedumpfile, it will check the phdr_ptr-paddr to see if it is page-size aligned and also phdr_ptr-p_memsz to get the real memory size, not including padding? No, it doesn't happen. p_offset is made page-size aligned for requirement to user-space linear-address vs file offset. The requirement for physical address is handled internally in vmcore_list, which is transparent to to user-space. Thanks. HATAYAMA, Daisuke -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 07/20] vmcore: copy non page-size aligned head and tail pages in 2nd kernel
于 2013年03月02日 16:36, HATAYAMA Daisuke 写道:
> Due to mmap() requirement, we need to copy pages not starting or
> ending with page-size aligned address in 2nd kernel and to map them to
> user-space.
>
> For example, see the map below:
>
> -0001 : reserved
> 0001-0009f7ff : System RAM
> 0009f800-0009 : reserved
>
> where the System RAM ends with 0x9f800 that is not page-size
> aligned. This map is divided into two parts:
>
> 0001-0009dfff
0001-0009efff
> 0009f000-0009f7ff
>
> and the first one is kept in old memory and the 2nd one is copied into
> buffer on 2nd kernel.
>
> This kind of non-page-size-aligned area can always occur since any
> part of System RAM can be converted into reserved area at runtime.
>
> If not doing copying like this and if remapping non page-size aligned
> pages on old memory directly, mmap() had to export memory which is not
> dump target to user-space. In the above example this is reserved
> 0x9f800-0xa.
>
> Signed-off-by: HATAYAMA Daisuke
> ---
>
> fs/proc/vmcore.c | 192
> --
> 1 files changed, 172 insertions(+), 20 deletions(-)
>
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index c511cf4..6b071b4 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -474,11 +474,10 @@ static int __init
> process_ptload_program_headers_elf64(char *elfptr,
> size_t elfsz,
> struct list_head *vc_list)
> {
> - int i;
> + int i, rc;
> Elf64_Ehdr *ehdr_ptr;
> Elf64_Phdr *phdr_ptr;
> loff_t vmcore_off;
> - struct vmcore *new;
>
> ehdr_ptr = (Elf64_Ehdr *)elfptr;
> phdr_ptr = (Elf64_Phdr*)(elfptr + ehdr_ptr->e_phoff); /* PT_NOTE hdr */
> @@ -488,20 +487,97 @@ static int __init
> process_ptload_program_headers_elf64(char *elfptr,
> PAGE_SIZE);
>
> for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
> + u64 start, end, rest;
> +
> if (phdr_ptr->p_type != PT_LOAD)
> continue;
>
> - /* 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;
> - list_add_tail(>list, vc_list);
> + start = phdr_ptr->p_offset;
> + end = phdr_ptr->p_offset + phdr_ptr->p_memsz;
> + rest = phdr_ptr->p_memsz;
> +
> + if (start & ~PAGE_MASK) {
> + u64 paddr, len;
> + char *buf;
> + struct vmcore *new;
> +
> + paddr = start;
> + len = min(roundup(start,PAGE_SIZE), end) - start;
> +
> + buf = (char *)get_zeroed_page(GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> + rc = read_from_oldmem(buf + (start & ~PAGE_MASK), len,
> + , 0);
> + if (rc < 0) {
> + free_pages((unsigned long)buf, 0);
> + return rc;
> + }
> +
> + new = get_new_element();
> + if (!new) {
> + free_pages((unsigned long)buf, 0);
> + return -ENOMEM;
> + }
> + new->flag |= MEM_TYPE_CURRENT_KERNEL;
> + new->size = PAGE_SIZE;
> + new->buf = buf;
> + list_add_tail(>list, vc_list);
> +
> + rest -= len;
> + }
> +
> + if (rest > 0 &&
> + roundup(start, PAGE_SIZE) < rounddown(end, PAGE_SIZE)) {
> + u64 paddr, len;
> + struct vmcore *new;
> +
> + paddr = roundup(start, PAGE_SIZE);
> + len =rounddown(end,PAGE_SIZE)-roundup(start,PAGE_SIZE);
> +
> + new = get_new_element();
> + if (!new)
> + return -ENOMEM;
> + new->paddr = paddr;
> + new->size = len;
> + list_add_tail(>list, vc_list);
> +
> + rest -= len;
> + }
> +
> + if (rest > 0) {
> + u64 paddr, len;
> + char *buf;
> + struct vmcore *new;
> +
> + paddr = rounddown(end, PAGE_SIZE);
> + len = end - rounddown(end, PAGE_SIZE);
> +
> + buf = (char *)get_zeroed_page(GFP_KERNEL);
> + if (!buf)
> + return
Re: [PATCH v2 07/20] vmcore: copy non page-size aligned head and tail pages in 2nd kernel
于 2013年03月02日 16:36, HATAYAMA Daisuke 写道:
Due to mmap() requirement, we need to copy pages not starting or
ending with page-size aligned address in 2nd kernel and to map them to
user-space.
For example, see the map below:
-0001 : reserved
0001-0009f7ff : System RAM
0009f800-0009 : reserved
where the System RAM ends with 0x9f800 that is not page-size
aligned. This map is divided into two parts:
0001-0009dfff
0001-0009efff
0009f000-0009f7ff
and the first one is kept in old memory and the 2nd one is copied into
buffer on 2nd kernel.
This kind of non-page-size-aligned area can always occur since any
part of System RAM can be converted into reserved area at runtime.
If not doing copying like this and if remapping non page-size aligned
pages on old memory directly, mmap() had to export memory which is not
dump target to user-space. In the above example this is reserved
0x9f800-0xa.
Signed-off-by: HATAYAMA Daisuke d.hatay...@jp.fujitsu.com
---
fs/proc/vmcore.c | 192
--
1 files changed, 172 insertions(+), 20 deletions(-)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index c511cf4..6b071b4 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -474,11 +474,10 @@ static int __init
process_ptload_program_headers_elf64(char *elfptr,
size_t elfsz,
struct list_head *vc_list)
{
- int i;
+ int i, rc;
Elf64_Ehdr *ehdr_ptr;
Elf64_Phdr *phdr_ptr;
loff_t vmcore_off;
- struct vmcore *new;
ehdr_ptr = (Elf64_Ehdr *)elfptr;
phdr_ptr = (Elf64_Phdr*)(elfptr + ehdr_ptr-e_phoff); /* PT_NOTE hdr */
@@ -488,20 +487,97 @@ static int __init
process_ptload_program_headers_elf64(char *elfptr,
PAGE_SIZE);
for (i = 0; i ehdr_ptr-e_phnum; i++, phdr_ptr++) {
+ u64 start, end, rest;
+
if (phdr_ptr-p_type != PT_LOAD)
continue;
- /* 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;
- list_add_tail(new-list, vc_list);
+ start = phdr_ptr-p_offset;
+ end = phdr_ptr-p_offset + phdr_ptr-p_memsz;
+ rest = phdr_ptr-p_memsz;
+
+ if (start ~PAGE_MASK) {
+ u64 paddr, len;
+ char *buf;
+ struct vmcore *new;
+
+ paddr = start;
+ len = min(roundup(start,PAGE_SIZE), end) - start;
+
+ buf = (char *)get_zeroed_page(GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ rc = read_from_oldmem(buf + (start ~PAGE_MASK), len,
+ paddr, 0);
+ if (rc 0) {
+ free_pages((unsigned long)buf, 0);
+ return rc;
+ }
+
+ new = get_new_element();
+ if (!new) {
+ free_pages((unsigned long)buf, 0);
+ return -ENOMEM;
+ }
+ new-flag |= MEM_TYPE_CURRENT_KERNEL;
+ new-size = PAGE_SIZE;
+ new-buf = buf;
+ list_add_tail(new-list, vc_list);
+
+ rest -= len;
+ }
+
+ if (rest 0
+ roundup(start, PAGE_SIZE) rounddown(end, PAGE_SIZE)) {
+ u64 paddr, len;
+ struct vmcore *new;
+
+ paddr = roundup(start, PAGE_SIZE);
+ len =rounddown(end,PAGE_SIZE)-roundup(start,PAGE_SIZE);
+
+ new = get_new_element();
+ if (!new)
+ return -ENOMEM;
+ new-paddr = paddr;
+ new-size = len;
+ list_add_tail(new-list, vc_list);
+
+ rest -= len;
+ }
+
+ if (rest 0) {
+ u64 paddr, len;
+ char *buf;
+ struct vmcore *new;
+
+ paddr = rounddown(end, PAGE_SIZE);
+ len = end - rounddown(end, PAGE_SIZE);
+
+ buf = (char *)get_zeroed_page(GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ rc = read_from_oldmem(buf, len, paddr, 0);
+ if (rc 0) {
+
