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Commit f2bdacdd authored by HATAYAMA Daisuke's avatar HATAYAMA Daisuke Committed by Linus Torvalds
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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: 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 b27eb186

fs/proc/vmcore.c

+51 −68
Original line number Diff line number Diff line
@@ -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,

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);