The patch titled
kexec jump: check code size in control page
has been added to the -mm tree. Its filename is
kexec-jump-check-code-size-in-control-page.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: kexec jump: check code size in control page
From: Huang Ying <ying.huang@xxxxxxxxx>
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.
Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/machine_kexec_32.c | 2 +-
arch/x86/kernel/relocate_kernel_32.S | 10 +++++++---
arch/x86/kernel/vmlinux_32.lds.S | 6 ++++++
include/asm-x86/kexec.h | 4 ++++
4 files changed, 18 insertions(+), 4 deletions(-)
diff -puN arch/x86/kernel/machine_kexec_32.c~kexec-jump-check-code-size-in-control-page arch/x86/kernel/machine_kexec_32.c
--- a/arch/x86/kernel/machine_kexec_32.c~kexec-jump-check-code-size-in-control-page
+++ a/arch/x86/kernel/machine_kexec_32.c
@@ -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);
diff -puN arch/x86/kernel/relocate_kernel_32.S~kexec-jump-check-code-size-in-control-page arch/x86/kernel/relocate_kernel_32.S
--- a/arch/x86/kernel/relocate_kernel_32.S~kexec-jump-check-code-size-in-control-page
+++ a/arch/x86/kernel/relocate_kernel_32.S
@@ -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
diff -puN arch/x86/kernel/vmlinux_32.lds.S~kexec-jump-check-code-size-in-control-page arch/x86/kernel/vmlinux_32.lds.S
--- a/arch/x86/kernel/vmlinux_32.lds.S~kexec-jump-check-code-size-in-control-page
+++ a/arch/x86/kernel/vmlinux_32.lds.S
@@ -210,3 +210,9 @@ SECTIONS
DWARF_DEBUG
}
+
+/* Link time checks */
+#include <asm/kexec.h>
+
+ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
+ "kexec control code size is too big")
diff -puN include/asm-x86/kexec.h~kexec-jump-check-code-size-in-control-page include/asm-x86/kexec.h
--- a/include/asm-x86/kexec.h~kexec-jump-check-code-size-in-control-page
+++ a/include/asm-x86/kexec.h
@@ -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>
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
origin.patch
kexec-jump-clean-up-ifdef-and-comments.patch
kexec-jump-rename-kexec_control_code_size-to-kexec_control_page_size.patch
kexec-jump-check-code-size-in-control-page.patch
kexec-jump-remove-duplication-of-kexec_restart_prepare.patch
kexec-jump-in-sync-with-hibernation-implementation.patch
kexec-jump-__ftrace_enabled_save-restore.patch
kexec-jump-fix-for-ftrace.patch
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