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kexec jump: check code size in control page

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Kexec/Kexec-jump require code size in control page is less than
PAGE_SIZE/2.  This patch add link-time checking for this.

ASSERT() of ld link script is used as the link-time checking mechanism.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Huang Ying 2008-08-15 00:40:23 -07:00 committed by Linus Torvalds
parent 163f6876f5
commit fb45daa69d
4 changed files with 20 additions and 4 deletions
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2
arch/x86/kernel/machine_kexec_32.c
View file

@ -138,7 +138,7 @@ void machine_kexec(struct kimage *image)
}
control_page = page_address(image->control_code_page);
memcpy(control_page, relocate_kernel, PAGE_SIZE/2);
memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
relocate_kernel_ptr = control_page;
page_list[PA_CONTROL_PAGE] = __pa(control_page);

10
arch/x86/kernel/relocate_kernel_32.S
View file

@ -20,10 +20,11 @@
#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define PAE_PGD_ATTR (_PAGE_PRESENT)
/* control_page + PAGE_SIZE/2 ~ control_page + PAGE_SIZE * 3/4 are
* used to save some data for jumping back
/* control_page + KEXEC_CONTROL_CODE_MAX_SIZE
* ~ control_page + PAGE_SIZE are used as data storage and stack for
* jumping back
*/
#define DATA(offset) (PAGE_SIZE/2+(offset))
#define DATA(offset) (KEXEC_CONTROL_CODE_MAX_SIZE+(offset))
/* Minimal CPU state */
#define ESP DATA(0x0)
@ -376,3 +377,6 @@ swap_pages:
popl %ebx
popl %ebp
ret
.globl kexec_control_code_size
.set kexec_control_code_size, . - relocate_kernel

8
arch/x86/kernel/vmlinux_32.lds.S
View file

@ -209,3 +209,11 @@ SECTIONS
DWARF_DEBUG
}
#ifdef CONFIG_KEXEC
/* Link time checks */
#include <asm/kexec.h>
ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
"kexec control code size is too big")
#endif

4
include/asm-x86/kexec.h
View file

@ -41,6 +41,10 @@
# define PAGES_NR 17
#endif
#ifdef CONFIG_X86_32
# define KEXEC_CONTROL_CODE_MAX_SIZE 2048
#endif
#ifndef __ASSEMBLY__
#include <linux/string.h>