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vmcore: allocate buffer for ELF headers on page-size alignment 

Allocate ELF headers on page-size boundary using __get_free_pages()
instead of kmalloc().

Later patch will merge PT_NOTE entries into a single unique one and
decrease the buffer size actually used.  Keep original buffer size in
variable elfcorebuf_sz_orig to kfree the buffer later and actually used
buffer size with rounded up to page-size boundary in variable
elfcorebuf_sz separately.

The size of part of the ELF buffer exported from /proc/vmcore is
elfcorebuf_sz.

The merged, removed PT_NOTE entries, i.e.  the range [elfcorebuf_sz,
elfcorebuf_sz_orig], is filled with 0.

Use size of the ELF headers as an initial offset value in
set_vmcore_list_offsets_elf{64,32} and
process_ptload_program_headers_elf{64,32} in order to indicate that the
offset includes the holes towards the page boundary.

As a result, both set_vmcore_list_offsets_elf{64,32} have the same
definition.  Merge them as set_vmcore_list_offsets.

[akpm@linux-foundation.org: add free_elfcorebuf(), cleanups]
Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: Vivek 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
HATAYAMA Daisuke 2013-07-03 15:02:14 -07:00 committed by Linus Torvalds
parent b27eb18660
commit f2bdacdd59
1 changed files with 51 additions and 68 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

119
fs/proc/vmcore.c
View File

@ -32,6 +32,7 @@ static LIST_HEAD(vmcore_list);
/* Stores the pointer to the buffer containing kernel elf core headers. */
static char *elfcorebuf;
static size_t elfcorebuf_sz;
static size_t elfcorebuf_sz_orig;
/* Total size of vmcore file. */
static u64 vmcore_size;
@ -186,7 +187,7 @@ static struct vmcore* __init get_new_element(void)
return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
}
static u64 __init get_vmcore_size_elf64(char *elfptr)
static u64 __init get_vmcore_size_elf64(char *elfptr, size_t elfsz)
{
int i;
u64 size;
@ -195,7 +196,7 @@ static u64 __init get_vmcore_size_elf64(char *elfptr)
ehdr_ptr = (Elf64_Ehdr *)elfptr;
phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr));
size = elfsz;
for (i = 0; i < ehdr_ptr->e_phnum; i++) {
size += phdr_ptr->p_memsz;
phdr_ptr++;
@ -203,7 +204,7 @@ static u64 __init get_vmcore_size_elf64(char *elfptr)
return size;
}
static u64 __init get_vmcore_size_elf32(char *elfptr)
static u64 __init get_vmcore_size_elf32(char *elfptr, size_t elfsz)
{
int i;
u64 size;
@ -212,7 +213,7 @@ static u64 __init get_vmcore_size_elf32(char *elfptr)
ehdr_ptr = (Elf32_Ehdr *)elfptr;
phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr));
size = elfsz;
for (i = 0; i < ehdr_ptr->e_phnum; i++) {
size += phdr_ptr->p_memsz;
phdr_ptr++;
@ -294,6 +295,8 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
*elfsz = *elfsz - i;
memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
memset(elfptr + *elfsz, 0, i);
*elfsz = roundup(*elfsz, PAGE_SIZE);
/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
@ -375,6 +378,8 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
*elfsz = *elfsz - i;
memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
memset(elfptr + *elfsz, 0, i);
*elfsz = roundup(*elfsz, PAGE_SIZE);
/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
@ -398,8 +403,7 @@ static int __init process_ptload_program_headers_elf64(char *elfptr,
phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
/* First program header is PT_NOTE header. */
vmcore_off = sizeof(Elf64_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
vmcore_off = elfsz +
phdr_ptr->p_memsz; /* Note sections */
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
@ -435,8 +439,7 @@ static int __init process_ptload_program_headers_elf32(char *elfptr,
phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
/* First program header is PT_NOTE header. */
vmcore_off = sizeof(Elf32_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
vmcore_off = elfsz +
phdr_ptr->p_memsz; /* Note sections */
for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
@ -459,18 +462,14 @@ static int __init process_ptload_program_headers_elf32(char *elfptr,
}
/* Sets offset fields of vmcore elements. */
static void __init set_vmcore_list_offsets_elf64(char *elfptr,
struct list_head *vc_list)
static void __init set_vmcore_list_offsets(size_t elfsz,
struct list_head *vc_list)
{
loff_t vmcore_off;
Elf64_Ehdr *ehdr_ptr;
struct vmcore *m;
ehdr_ptr = (Elf64_Ehdr *)elfptr;
/* Skip Elf header and program headers. */
vmcore_off = sizeof(Elf64_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);
vmcore_off = elfsz;
list_for_each_entry(m, vc_list, list) {
m->offset = vmcore_off;
@ -478,24 +477,10 @@ static void __init set_vmcore_list_offsets_elf64(char *elfptr,
}
}
/* Sets offset fields of vmcore elements. */
static void __init set_vmcore_list_offsets_elf32(char *elfptr,
struct list_head *vc_list)
static void free_elfcorebuf(void)
{
loff_t vmcore_off;
Elf32_Ehdr *ehdr_ptr;
struct vmcore *m;
ehdr_ptr = (Elf32_Ehdr *)elfptr;
/* Skip Elf header and program headers. */
vmcore_off = sizeof(Elf32_Ehdr) +
(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);
list_for_each_entry(m, vc_list, list) {
m->offset = vmcore_off;
vmcore_off += m->size;
}
free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
elfcorebuf = NULL;
}
static int __init parse_crash_elf64_headers(void)
@ -526,31 +511,31 @@ static int __init parse_crash_elf64_headers(void)
}
/* Read in all elf headers. */
elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
ehdr.e_phnum * sizeof(Elf64_Phdr);
elfcorebuf_sz = elfcorebuf_sz_orig;
elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
get_order(elfcorebuf_sz_orig));
if (!elfcorebuf)
return -ENOMEM;
addr = elfcorehdr_addr;
rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
if (rc < 0) {
kfree(elfcorebuf);
return rc;
}
rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
if (rc < 0)
goto fail;
/* Merge all PT_NOTE headers into one. */
rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
if (rc)
goto fail;
rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
&vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
if (rc)
goto fail;
set_vmcore_list_offsets(elfcorebuf_sz, &vmcore_list);
return 0;
fail:
free_elfcorebuf();
return rc;
}
static int __init parse_crash_elf32_headers(void)
@ -581,31 +566,30 @@ static int __init parse_crash_elf32_headers(void)
}
/* Read in all elf headers. */
elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
elfcorebuf_sz = elfcorebuf_sz_orig;
elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
get_order(elfcorebuf_sz_orig));
if (!elfcorebuf)
return -ENOMEM;
addr = elfcorehdr_addr;
rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
if (rc < 0) {
kfree(elfcorebuf);
return rc;
}
rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0);
if (rc < 0)
goto fail;
/* Merge all PT_NOTE headers into one. */
rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
if (rc)
goto fail;
rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
&vmcore_list);
if (rc) {
kfree(elfcorebuf);
return rc;
}
set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
if (rc)
goto fail;
set_vmcore_list_offsets(elfcorebuf_sz, &vmcore_list);
return 0;
fail:
free_elfcorebuf();
return rc;
}
static int __init parse_crash_elf_headers(void)
@ -629,14 +613,14 @@ static int __init parse_crash_elf_headers(void)
return rc;
/* Determine vmcore size. */
vmcore_size = get_vmcore_size_elf64(elfcorebuf);
vmcore_size = get_vmcore_size_elf64(elfcorebuf, elfcorebuf_sz);
} else if (e_ident[EI_CLASS] == ELFCLASS32) {
rc = parse_crash_elf32_headers();
if (rc)
return rc;
/* Determine vmcore size. */
vmcore_size = get_vmcore_size_elf32(elfcorebuf);
vmcore_size = get_vmcore_size_elf32(elfcorebuf, elfcorebuf_sz);
} else {
pr_warn("Warning: Core image elf header is not sane\n");
return -EINVAL;
@ -683,7 +667,6 @@ void vmcore_cleanup(void)
list_del(&m->list);
kfree(m);
}
kfree(elfcorebuf);
elfcorebuf = NULL;
free_elfcorebuf();
}
EXPORT_SYMBOL_GPL(vmcore_cleanup);